Veterinary Arthroscopy for the Small Animal Practitioner [1 ed.] 1119548977, 9781119548973

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Veterinary Arthroscopy for the Small Animal Practitioner

Veterinary Arthroscopy for the Small Animal Practitioner Edited By

Timothy C. McCarthy, DVM, PhD

Diplomate, American College of Veterinary Surgeons ACVS Founding Fellow, Minimally Invasive Surgery (Small Animal Soft Tissue) ACVS Founding Fellow, Minimally Invasive Surgery (Small Animal Orthopedics) Veterinary Minimally Invasive Surgery Training (VetMIST) Beaverton, OR, USA

This edition first published 2021 © 2021 John Wiley & Sons, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions. The right of Timothy C. McCarthy to be identified as the author of this work has been asserted in accordance with law. Registered Office John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA Editorial Office 111 River Street, Hoboken, NJ 07030, USA For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com. Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of this book may not be available in other formats. Limit of Liability/Disclaimer of Warranty The contents of this work are intended to further general scientific research, understanding, and discussion only and are not intended and should not be relied upon as recommending or promoting scientific method, diagnosis, or treatment by veterinarians for any particular patient. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of medicines, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each medicine, equipment, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. Library of Congress Cataloging-in-Publication Data Names: McCarthy, Timothy C., author. Title: Veterinary arthroscopy for the small animal practitioner / Timothy C. McCarthy. Description: First edition. | Hoboken, NJ : Wiley-Blackwell, 2021. | Includes bibliographical references and index. Identifiers: LCCN 2020035416 (print) | LCCN 2020035417 (ebook) | ISBN 9781119548973 (hardback) | ISBN 9781119549017 (adobe pdf) | ISBN 9781119549024 (epub) Subjects: LCSH: Veterinary arthroscopy. | Veterinary orthopedics. | Joints–Examination. | Veterinary diagnostic imaging. | Pet medicine. Classification: LCC SF910.5 .M33 2021 (print) | LCC SF910.5 (ebook) | DDC 636.089/705–dc23 LC record available at https://lccn.loc.gov/2020035416 LC ebook record available at https://lccn.loc.gov/2020035417 Cover Design: Wiley Cover Image: © Courtesy of Timothy C. McCarthy Set in 9.5/12.5pt STIXTwoText by SPi Global, Pondicherry, India 10  9  8  7  6  5  4  3  2  1

I dedicate this book to all my patients. Without their participation, this would not have been possible

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Contents Preface  xi Acknowledgments  xiii About the Companion Website  xiv 1 Introduction and Instrumentation  1 1.1 Introduction  1 1.2 Instrumentation and Equipment  3 1.2.1 Arthroscopes  3 1.2.2 Sheaths and Cannulas  5 1.2.2.1 Telescope Sheaths  5 1.2.2.2 Operative Cannulas  6 1.2.2.3 Egress Cannulas  8 1.2.3 Operative Hand Instruments  8 1.2.4 Power Instruments  12 1.2.4.1 Power Shavers  12 1.2.4.2 Radiofrequency/Electrocautery Instrumentation  14 1.2.5 Irrigation Fluid and Management Systems  15 1.2.5.1 Irrigation Fluids  15 1.2.5.2 Gravity Flow  16 1.2.5.3 Pressure Assisted Flow  16 1.2.5.4 Mechanical Arthroscopy Fluid Pumps  16 1.2.6 Video System Tower  17 1.2.6.1 Video Camera  18 1.2.6.2 Video Monitor  19 1.2.6.3 Light Source  19 1.2.6.4 Documentation Equipment  20 References  20 2 General Technique  23 2.1 ­Anesthesia, Patient Support, and Pain Management  23 2.2 ­Postoperative Care  23 2.3 ­Patient Preparation, Positioning, and Operating Room Setup  24 2.3.1 Shoulder Joint  24 2.3.2 Elbow Joint  26 2.3.3 Radiocarpal Joint  28 2.3.4 Hip Joint  29 2.3.5 Stifle Joint  29 2.3.6 Tibiotarsal Joint  31 2.4 ­Portal Placement-General  31 References   34

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3 Shoulder Joint  36 3.1 ­Patient Preparation, Positioning, and Operating Room Setup  36 3.2 ­Portal Sites and Portal Placement  37 3.2.1 Telescope Portals  37 3.2.2 Operative Portals  39 3.2.3 Egress Portals  40 3.3 ­Nerves of Concern with Shoulder Joint Arthroscopy  40 3.4 ­Examination Protocol and Normal Arthroscopic Anatomy  41 3.5 ­Diseases of the Shoulder Diagnosed and Managed with Arthroscopy  47 3.5.1 Osteochondritis Dissecans (OCD)  47 3.5.1.1 OCD Lesion Removal and Management  59 3.5.2 Bicipital Tendon Injuries  73 3.5.3 Soft Tissue Injuries of the Shoulder with or Without Shoulder Instability  81 3.5.4 Ununited Caudal Glenoid Ossification Center (UCGOC)  95 3.5.5 Ununited Supraglenoid Tubercle (USGT)  100 3.5.6 Arthroscopic-Assisted Intra-Articular Fracture Repair  100 3.5.7 Arthroscopic Biopsy of Intra-Articular Neoplasia  101 3.5.8 Glenoid Cartilage Defects  102 3.5.9 Chondromalacia  104 3.5.10 Infraspinatus Muscle Contracture  104 References  106 4 Arthroscopy of the Elbow Joint  108 4.1 ­Patient Preparation, Positioning, and Operating Room Setup  108 4.2 ­Portal Sites and Portal Placement  109 4.2.1 Telescope Portals (Medial, Craniolateral, Caudomedial, and Caudal)  109 4.2.2 Operative Portals (Craniomedial, Lateral, Craniolateral, and Caudal)  111 4.2.3 Egress Portals  113 4.3 ­Nerves of Concern with Elbow Joint Arthroscopy  113 4.4 ­Examination Protocol and Normal Arthroscopic Anatomy  114 4.5 ­Diseases of the Elbow Diagnosed and Managed with Arthroscopy  122 4.5.1 Elbow Dysplasia  122 4.5.2 Osteochondritis Dissecans (OCD)  167 4.5.3 Ununited Anconeal Process (UAP)  176 4.5.4 Degenerative Joint Disease (DJD)  180 4.5.5 Assisted Intra-Articular Fracture Repair  180 4.5.6 Biopsy of Intra-Articular Neoplasia  181 4.5.7 Immune-Mediated Erosive Arthritis  182 4.5.8 Incomplete Ossification of the Humeral Condyle (IOHC)  182 4.5.9 Medial Enthesiopathy  183 References  184 5 Radiocarpal Joint  187 5.1 ­Patient Preparation, Positioning, and Operating Room Setup  187 5.2 ­Portal Sites and Portal Placement  187 5.3 ­Nerves of Concern with Radiocarpal Joint Arthroscopy  187 5.4 ­Examination Protocol and Normal Arthroscopic Anatomy  188 5.5 ­Diseases of the Radiocarpal Joint Diagnosed and Managed with Arthroscopy  189 5.5.1 Fractures  189 5.5.2 Soft Tissue Injuries  190 5.5.3 Immune-Mediated Erosive Arthritis  190 References  191

Contents

6 Hip Joint  192 6.1 ­Patient Preparation, Positioning, and Operating Room Setup  192 6.2 ­Portal Sites and Portal Placement  192 6.3 ­Nerves of Concern with Hip Joint Arthroscopy  193 6.4 ­Examination Protocol and Normal Arthroscopic Anatomy  193 6.5 ­Diseases of the Hip Diagnosed and Managed with Arthroscopy  196 6.5.1 Hip Dysplasia  196 6.5.2 Arthroliths  202 6.5.3 Soft Tissue Injuries of the Hip Joint  203 6.5.4 Assisted Intra-Articular Fracture Repair  205 6.5.5 Biopsy of Intra-Articular Neoplasia  206 6.5.6 Aseptic Necrosis of the Femoral Head  206 References  206 7 Stifle Joint  207 7.1 ­Patient Preparation, Positioning, and Operating Room Setup  210 7.2 ­Portal Sites and Portal Placement  210 7.2.1 Telescope Portal  210 7.2.2 Operative Portals  211 7.2.3 Egress Portal  211 7.3 ­Nerves of Concern with Stifle Joint Arthroscopy  213 7.4 ­Examination Protocol and Normal Arthroscopic Anatomy  213 7.5 ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscopy  221 7.5.1 Cranial Cruciate Ligament Injuries  221 7.5.2 Caudal Cruciate Ligament Injuries  258 7.5.3 Isolated Meniscal Injuries  258 7.5.4 Osteochondritis Dissecans(OCD)  259 7.5.5 Stifle Stabilization Failures  264 7.5.6 TPLO Second Look  264 7.5.7 Patellar Fracture Management  266 7.5.8 Long Digital Extensor Tendon Injuries  268 7.5.9 Popliteal Tendon Avulsion  268 7.5.10 Intra-articular Neoplasia  269 7.5.11 Patellar Luxation  270 7.5.12 Degenerative Joint Disease, Chondromalacia, and Synovitis  270 7.5.13 Discoid Meniscus  273 7.5.14 Osteochondromatosis  274 References  274 8 Tibiotarsal Joint  276 8.1 ­Patient Preparation, Positioning, and Operating Room Setup  276 8.2 ­Portal Sites and Portal Placement  276 8.2.1 Telescope Portals  276 8.2.2 Operative Portals  277 8.2.3 Egress Portal  278 8.3 ­Nerves of Concern with Tibiotarsal Joint Arthroscopy  278 8.4 ­Examination Protocol and Normal Arthroscopic Anatomy  278 8.5 ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscopy  279 8.5.1 Osteochondritis Dissecans (OCD)  279 8.5.2 Intra-Articular Fracture Management  286 8.5.3 Soft Tissue Injuries  287

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8.5.4 Immune-Mediated Erosive Arthritis  287 8.5.5 Osteoarthritis  289 References  291 9 Problems and Complications  292 9.1 ­Actual and Potential Complications of Arthroscopy  292 9.1.1 Failure to Enter the Joint  292 9.1.2 Articular Cartilage Damage  292 9.1.3 Soft Tissue Damage  296 9.1.4 Bone Fragment Displacement  298 9.1.5 Operative Debris  298 9.1.6 Red Out  299 9.1.7 Peri-articular Fluid Accumulation  300 9.1.8 Infection  300 9.1.9 Vascular Injury  301 9.1.10 Nerve Injury  301 9.2 ­Instrument Damage  301 9.2.1 Intra-articular Instrument Breakage  301 9.2.2 Telescope Breakage  302 9.3 ­Contraindications  303 9.3.1 Patient Size  303 9.3.2 Septic Arthritis  303 9.3.3 Anesthesia Risk  303 References  304 Index  305

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Preface While writing this book, my 50 year anniversary of graduation from Veterinary School occurred. Fifty years! This has been an incredible journey! Beyond my wildest dreams. I never thought that I would be where I am today and would have done the things that I have done. I never dreamed that the first edition of this book would be translated into Russian or that I would be invited to Russia to launch its sale and teach Russian Veterinarians. I never dreamed that I would travel to teach in 14 countries and 23 states. That I would publish books about my professional work. It is amazing that I was even able to become a Veterinarian. I am so dyslexic that I struggled to learn to read. When I started the fifth grade, I was reading at a second grade level. Spelling was impossible. In the third grade, I was able to get 49 out of 50 words WRONG on a review spelling test even after spending uncountable hours with my parents trying to learn spelling using flash cards. People with really bad handwriting are probably dyslexic and with really bad handwriting no one can tell how the word was spelled. I think that I got into Veterinary School with the lowest grades in the history of Veterinary Medicine, but Baxter Black and I debate who’s was worst. If it were not for Dr. Don Bailey, I would not have been accepted. He worked for Dr. Davis, who was head of the admission committee when I applied, all through Veterinary School and graduated at the top of this class. I managed to not flunk out and graduated at the bottom of the class, again Baxter Black and I argue about who was really “last in class.” And they call the person who graduates last in class “Dr.” It was obvious in my first job out of school that I wanted to do surgery. Residency programs for advanced training were a new entity 50 years ago and they were few and far between. Then how does someone with grades barely above 2.0 get into a residency program? NOT! I finally thought that I needed to try CSU, my “amalater.” They did not have a residency program, but there was the graduate program at the Surgery Lab. I

interviewed with the head of the program and, during the interview, it was obvious that if I applied for the masters degree program there was no chance that I would be accepted but if I applied for the PhD program I was guaranteed to be accepted. Interesting but it worked. Six years later I passed the ACVS examination and became a board-certified surgeon and, in a few years later, won my PhD. ACVS recently initiated fellowship training in minimally invasive surgery, and I was selected as a founding fellow in this program for both small animal soft tissue surgery and small animal orthopedics, the only veterinarian to qualify for both categories. At my 25 year class reunion, I was informed that at a previous time I had been unanimously selected as the classmate least likely to go back to school AND they were “Stunned” that I was board certified. My reply was that no one is more stunned than I. Getting into endoscopy happened totally by chance. I got a call from a local veterinarian asking if I wanted to buy a used gastroscope that he had. As a surgeon, I had never really thought about doing GI endoscopy but thought, “hey why not” since no one in the area was providing this service. I did not buy that endoscope but bought another one that was in better shape for $550 with a light source and all the instruments that I needed. A little later, I bought a laparoscope to do liver biopsies and then an arthroscope. I never thought that I would pay for this equipment, but I thought it would be fun, I might be able to practice better medicine, and I could afford the expense. I started putting endoscopes everywhere and added to the list of procedures that could be performed by trying new things on my patients. Many of the endoscopic first ever procedures were performed on patients with clinical problems. Using the axiom of “Above all do no harm” and combining endoscopy with transition to traditional approaches, there were an unbelievingly low number of problems or complications. Very few firsts

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Preface

were planned or thought about ahead of time and many were spur of the moment events added to an already ongoing procedure or immediately before surgery by asking the question, can I do this with a scope? In cases where the question was asked before surgery the discussion with the client was, I would like to try this with minimally invasive technique, I have never done this before or this has never been done before, if I cannot do this with minimally invasive technique I will do it the traditional old way, and the cost will by the same how matter how it gets done. I never had a client say no to this plan. Sure, I had to eat some of the cost on many early cases, but this is the easiest, most effective, cheapest continuing education I have ever gotten and has benefitted the patients, clients, my practice, my happiness, plus my pocketbook thousands of times over the cost. Sixty endoscopes and over 7000 procedures later I am writing the second edition of this book. I know that I am different and do not follow the book. I am so dyslexic that I cannot read about what I am not supposed to be able to do. I also never learned to come in out of the rain because my mother took me out in the rain. In the first grade, when we had art class all the class got coloring books, but the teacher did not give me one. Being a typical first grader, I was devastated and did not understand why I did not get a coloring book. The teacher then brought me a large blank piece of paper and told me that my mother did not want me to have a coloring book but wanted me to make my own drawings. So, I never learned to color between the lines. In fact, I never learned that there were lines. When someone says something about thinking outside the box my question is, what is a box? As I said at the beginning, my career has been an incredible journey. But it has not all been easy or fun. There have been times of miserable struggle. I belong to the face book group; “Not one more vet,” because I am a suicide survivor. Twice in my life I have been at the edge. Fortunately, I never acted on my thoughts of suicide and am here to tell about the experience. If I can get through this so can you. I looked for and got help from my friends and great help from some great Psychologists. I also have to admit that I am really stubborn and wasn’t going to let the b’s win. If you are in trouble, get help! Working with a psychologist has changed my life. It does not mean that if you see a Psychologist that there is something wrong with you. Get over this mental block. Unburden yourself to them, that is what they are there for. At my first visit

with my first Psychologist, I unloaded everything that was bothering me, things that I never thought I would ever tell anyone, at the end of the session she said that I saved about nine months of therapy because I was ready and she did not have to spend that time breaking down my resistance. We went from there. I am a much happier person, I have eliminated my anger issues, and I am much more resilient to the stresses in life. Early in this saga, I made the statement in my lectures: “Endoscopy is a quantum leap forward in our diagnostic and therapeutic armamentarium.” This was and still is true. Now I say “A patient comes into every veterinary practice every day who would benefit from a minimally invasive procedure” This is also true or when I get pushy: “Every patient who comes into every veterinary practice every day would benefit from a minimally invasive procedure” and this is almost true. Enjoy your endoscopes. They are the best burnout protection that you can buy.

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Acknowledgments This work would not have been accomplished without a great number of people and animals who collectively made this possible. I simply put it to paper. First to my parents for bringing me into this world and for their unending support, encouragement, and love. To Dr. Don and Betty Bailey for introducing me to Veterinary Medicine, for getting me into Veterinary School, and for their continued support throughout my career. To all my teachers and professors, from my first-grade teacher Mrs. Mathews, through high school and college for their efforts to educate and stimulate me but especially to Drs Jim Creed, Glenn Severin, Pat Chase, Harry Gorman, and Henry Swan. To my colleagues who referred the cases that provided me with the material for learning these techniques. And to the clients who entrusted me with their beloved pets. To Dr. Karl Storz, his daughter Ms. Sible Storz, and his grandson Mr. Karl-Christian Storz for their interest in Veterinary Medicine and support of our profession. To all the staff of the Veterinary Division of the Karl Storz Endoscope Company for their educational endeavors and instrumentation development for our profession. Especially to Dr. Christopher Chamness for his support, encouragement, and friendship. To all the younger veterinarians who have picked up the reins and are driving all aspects of endoscopy forward at an ever-increasing rate. I am thrilled that I now only see smoke and taillights. This is a thrill to watch. And most importantly, to my wife and son for their patience and for allowing me the time to complete this project.

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­About the Companion Website This book is accompanied by a companion website: www.wiley.com/go/mccarthy/arthroscopy The website includes: OO

Videos

Note: The videos are clearly signposted throughout the book. Look out for

.

1

1 Introduction and Instrumentation 1.1 ­Introduction Arthroscopy is the most significant advance in small animal orthopedics that has occurred during my 50 years of professional lifetime. Arthroscopy provides more information about intraarticular pathology than any other diagnostic technique. The most important advantages of arthroscopy are visual access to more joint area, magnification produced by the telescopes and video systems, excellent illumination, and a clear visual field when continuous irrigation is employed. Arthroscopy is also minimally invasive, reduces trauma, shortens operative times, and decreases recovery times. The small sizes of telescopes available today allow placement into the deepest parts of joints and combined with angulation of the field of view, 30° for most arthroscopes, provide visual access to more area of joints than can be achieved with open surgery. Arthroscopes magnify intra-articular structures allowing visualization of anatomical details and pathologic changes that are beyond the resolution of radiographs, CT, MRI, or what can be seen with open surgery (Video 1.1). Submacroscopic lesions that elude us with open surgical exploration can be easily seen with arthroscopy. High-intensity lighting is passed directly through the arthroscope providing perfect illumination of everything in the field of view of the telescope. Irrigation employed with arthroscopy maintains a clear field of view by continuously flushing blood and debris away from the end of the telescope. This is all done with minimally invasive technique and far less tissue trauma than with an arthrotomy. Speed is not the most important criteria or the most important advantage of arthroscopy over open arthrotomy, but for the experienced arthroscopic surgeon, anesthesia and procedure times are significantly shorter than with conventional open surgery. Postoperative recovery after arthroscopy is also much faster than following an open arthrotomy. This time comparison is an important

advantage of arthroscopy. Most dogs recover to their preoperative status of lameness and pain within a few hours after arthroscopy. Many dogs are better than their preoperative level of function by the time they are released from the hospital on the day after arthroscopy. Arthroscopy is commonly performed as an outpatient procedure with a release on the same day as surgery. Activity restriction is not needed for portal site healing. The time required for healing of intra-articular structures after arthroscopy for conditions such as OCD and medial coronoid process disease (MCPD) has not been studied or effectively compared with healing after open surgery. There are few disadvantages of arthroscopy. The most significant disadvantage is that arthroscopy is the most difficult of all endoscopies to learn. Arthroscopy’s technical difficulty with its long slow learning process for both diagnostic applications and for performing corrective surgical procedures makes it a challenge to gain proficiency. Arthroscopy requires considerable practice, patience, and persistence to master. Reasons for arthroscopy’s difficulty are related to the small space involved, confinement by rigid bony structures, and the anatomic complexity of some joints such as the stifle. Even with its difficulties, developing proficiency with arthroscopy is within the grasp of most who are willing to make the effort and put in the time to learn. Expense of instrumentation is a relative disadvantage as the cost of the equipment and instrumentation for arthroscopy is significant but is no more than other sophisticated instrumentation used in small animal practice today. The limitation of small patient size is shrinking as instrument size decreases and as our skill level and experience increase. Arthroscopy is indicated whenever there is a history, physical findings, imaging changes, or laboratory result suggestive of joint disease. A history of lameness, stiffness, difficulty or reluctance to get up, reluctance to go up or downstairs, reluctance to get up and

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

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1  Introduction and Instrumentation

down off the couch or the favorite chair, and inability to get in and out of the car or truck; combined with joint pain, swelling or thickening, crepitus, reduced range of joint motion, or joint instability on physical examination are definite reasons to perform arthroscopy. Radiographic, CT, MRI, or ultrasound abnormalities of increased joint fluid or joint capsule thickening, periarticular osteophytes, periarticular sclerosis, OCD lesions, ununited anconeal processes, ununited caudal glenoid ossification center, intra-articular fractures or chips, periarticular bone lysis, tendon and ligament abnormalities, or any other changes involving a joint are also indications for arthroscopy. Normal radiographic, CT, MRI, or ultrasound findings do not preclude arthroscopy as a diagnostic technique if history and physical findings point to joint involvement. Arthroscopy is indicated whenever we need more information about a joint than can be obtained with any less invasive technique. Arthroscopy is most commonly performed in the shoulder, elbow, and stifle in dogs. Arthroscopy is less commonly performed on the radiocarpal, hip, and tibiotarsal joints. Arthroscopy is easier to perform in large dogs but has been done effectively in dogs as small as seven pounds. Arthroscopy has also been performed in the shoulder, elbow, and stifle of cats but its use is largely unexplored in this species. The same positioning, procedures, techniques, and portals that are used in dogs are used for cats. Conditions that have been diagnosed with arthroscopy (Table  1.1) include osteochondritis dissecans (OCD) of the shoulder, stifle, elbow, and tibiotarsal joints (Van Bree and Van Ryssen  1998); partial and complete cranial and caudal cruciate ligament ruptures; meniscal injuries; medial coronoid processes disease (MCPD); ununited caudal glenoid ossification center (UCGOC), ununited anconeal process (UAP), ununited supraglenoid tubercle, degenerative joint disease (DJD); intra-articular fractures; immune-mediated arthritis; synovitis; partial or complete bicipital tendon rupture; injury to other intra-articular soft tissues of the shoulder, soft tissue injury of intra-articular structures of the elbow, radiocarpal, stifle, and hip joints; septic arthritis; and neoplasia. Arthroscopic assessment of femoral head and acetabular articular cartilage condition in young dysplastic dogs have been used for case selection and to predict results with pelvic osteotomy surgery. Cartilage injury or chondromalacia secondary to instability, deformity, or inflammatory processes is more easily identified and the extent of damage scored more accurately than with open surgery.

Table 1.1  Diagnoses with arthroscopy. All joints

Degenerative joint disease Chondromalacia Neoplasia Synovitis/villus synovial proliferation Intra-articular Fractures Immune-mediated polyarthropathies Septic arthritis

Shoulder joint

OCD of the humeral head Bicipital tendon ruptures – partial and complete Medial glenohumeral ligament and subscapularis tendon injuries Lateral glenoid labrum separations Ununited caudal glenoid ossification center Ununited supraglenoid tubercle Supraspinatus tendon injuries Glenoid cartilage defects

Elbow joint Medial coronoid process pathology/ fragmentation Lateral coronoid process pathology/ fragmentation OCD of the humeral condyle Ununited anconeal process Joint incongruity/growth deformity Incomplete humeral condyle ossification Radiocarpal Radial carpal bone fractures joint Chip fractures of the dorsal margin of the distal radius Ligament and joint capsule tears Hip joint

Hip dysplasia Dorsal joint capsule tears Aseptic necrosis of the femoral head

Stifle joint

Cranial cruciate ligament ruptures – partial and complete Caudal cruciate ligament ruptures – partial and complete Meniscal injuries OCD of the femoral condyle Medial patellar luxation/lateral patellar ligament rupture Long digital extensor tendon injuries Popliteal tendon avulsion Cruciate stabilization failure

Hock joint

OCD of the talus

Operative procedures currently being performed with arthroscopy (Table 1.2) include removal of OCD cartilage flaps and debridement of the cartilage defects in the shoulder, elbow, stifle, and tibiotarsal joints (Bertrand et al. 1997; Bilmont et al. 2018; Cook et al. 2001; Gielen et al. 2002; McCarthy 1999; Miller and Beale 2008; Olivieri

1.2  ­Instrumentation and Equipmen

Table 1.2  Operative procedures performed with arthroscopy. Shoulder joint

OCD cartilage flap removal and lesion debridement Bicipital tendon transection Ununited caudal glenoid ossification center fragment removal Ununited supraglenoid tubercle fragment removal Intra-articular soft tissue injury stabilization Intra-articular or assisted fracture repair

Elbow joint

Medial coronoid process fragment removal/process revision OCD cartilage flap removal and lesion debridement Anconeal process removal Osteophyte resection Intra-articular or assisted fracture repair

Radiocarpal joint

Carpal chip removal Intra-articular or assisted fracture repair

Stifle joint

Cruciate ligament debridement/removal Meniscectomy – partial/total OCD cartilage flap removal and lesion debridement Meniscal release Intra-articular or assisted fracture repair

Hock joint

OCD cartilage flap removal and lesion debridement Free joint body and tarsal chip fracture fragment removal Intra-articular or assisted fracture repair

et al. 2007; Person 1989; Rochat 2001; Van Bree and Van Ryssen  1998); coronoid process fragment removal (McCarthy 1999; Rochat 2001) and coronoid process revision or subtotal coronoidectomy (McCarthy  1999), free joint body (arthrolith) removal (Smith et al. 2012), bicipital tendon transection (Bergenhuyzen et  al.  2010; Cook et  al.  2005; Rochat  2001), carpal chip removal (McCarthy 2005), partial and total meniscectomy (Ertelt and Fehr 2009; Ridge 2006; Ritzo et al. 2014; Rochat 2001), cruciate ligament debridement (Rochat  2001), meniscal release (Austin et al. 2007; Kim et al. 2016; McCarthy 1999), ununited caudal glenoid ossification center removal (McCarthy  2005), ununited supraglenoid tubercle removal (McCarthy 2005; Serck and Wouters 2019), ununited anconeal process removal (McCarthy 2005), screw fixation of ununited anconeal process fragments, osteophyte removal in chronic degenerative joint disease of the elbow and tarsus (McCarthy 2005), intra-articular repair of ruptured cranial cruciate ligaments (Bolia and Böttcher 2015; Person 1987; Winkels et al. 2010), fixation

of avulsed ligament attachments, medial patellar luxation management (Bevan and Taylor 2004), assisted repair of intraarticular fractures (Beale and Cole 2012; Bright and May 2011; Cole and Beale 2020; Cusack and Johnson 2013; Deneuche and Viguier 2002; Perry et al. 2010), intra-articular management of shoulder instability (Franklin et  al.  2013; Mitchell and Innes  2000; Ridge et  al.  2014), neoplasia management (Arias et  al.  2009; Scherrer et al. 2005), septic arthritis management (Fearnside and Preston 2002; Luther et al. 2005), and more. The majority of procedures and publications relate to application of arthroscopy in dogs, but this technique has also been performed in cats (Bardet  1998; Beale and Cole  2012; Bright  2010; Cole and Beale  2020; Cusack and Johnson 2013; Mindner et al. 2016; Ridge 2009; Serck and Wouters 2019; Staiger and Beale 2005).

1.2 ­Instrumentation and Equipment 1.2.1  Arthroscopes Rigid telescopes used for arthroscopy range in size from 1.9 to 5.0 mm diameter. Telescopes in use today are designed using what is termed a Hopkins rod lens system (Figure  1.1) for image transmission that has dramatically improved image quality over previous lens systems. Telescopes commonly used for small animal arthroscopy (Table  1.3) include a long 2.7 mm arthroscope also called the 2.7 mm multipurpose rigid telescope (MPRT), a 4.0 mm arthroscope, a short 2.7 mm arthroscope, a 2.4 mm arthroscope, and a 1.9 mm arthroscope (Figure 1.2). These telescopes all have a 30° visual angle, but other angles are available (Figure 1.3). Each has advantages, disadvantages, and specific best applications. The 2.7 mm MPRT was for years promoted as the telescope of choice for arthroscopy in small animals because it had the best optics of all the small telescopes and its length allows it to be used for multiple endoscopic techniques. This recommendation has changed with improvement of the optics of the 2.4 mm arthroscope, which now equals or exceeds those of the 2.7 mm MPRT. The 2.4 scope is shorter, 11 cm vs 18 cm, smaller, with a better blunt obturator design making it much easier to insert and use in the small joints of our patients. This size and design allow procedures to be performed with less joint damage. One of the previous arguments for recommendation of the 2.7 mm MPRT was that it can be used for many endoscopic techniques commonly performed in small

3

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Figure 1.1  A diagram of the Hopkins rod lens system shown in the telescope at the bottom and a conventional lens system in the telescope at the top. Hopkins rod lenses are the standard design for arthroscopes in current use today. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Table 1.3  Telescopes used for small animal arthroscopy. Arthroscope diameter

Telescope length (cm)

Telescope angle (°)

4.0 mm

18

30

64230 BWA

12

30

a

67728 BWA

Endocameleon

8

15 T0 90 (Variable)

28731 AE

2.7 x Long (MPRT)

18

30

a

64029 BA

2.7 mm Short

11

30

a

2.4 mm

11

30

a

10

30

a

6.5

30

28305 BA

1.9 mm a

Telescope part number (Karl Storz)

67208 BA 64300 BA 64301 BA

 Shown in Figure A I 2.

0°

12°

30° Figure 1.2  Arthroscopes commonly used in small animal practice from bottom to top: the long 2.7 mm multipurpose rigid telescope (MPRT), 4.0 mm arthroscope, short 2.7 mm arthroscope, 2.4 mm arthroscope, and 1.9 mm arthroscope. These telescopes all have a viewing angle of 30°. The 2.7 mm multipurpose telescope has a working length of 18 cm; the 4.0 mm, short 2.7 mm, and 2.4 mm arthroscopes have a working length of 11 cm; and the 1.9 mm arthroscope with 6.5 cm working length. These telescopes are all autoclavable. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Figure 1.3  A diagram showing the angle of view of telescopes used for arthroscopy. Thirty degrees is the angle of view of all commonly used telescopes for arthroscopy. Zero degree and seventy degrees arthroscopes are available but are rarely used. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

1.2  ­Instrumentation and Equipmen

animal practice and is why this endoscope is termed the MPRT. The larger size of this telescope and the design of the blunt obturator increase the difficulty of establishing a telescope portal for arthroscopy. The other major disadvantage of this telescope is its length, which makes manipulations more difficult for arthroscopy with the finite movements needed for maneuvering the visual field within small joints combined with the long fulcrum produced by a video camera on the end of the telescope. The demands of arthroscopy for effective application in small animals today combined with the need for continued improvement in technique and results no longer allow us to substitute a multipurpose telescope, when a better single application instrument is available. The 2.4 mm arthroscope is currently the telescope of choice for small animal practice. A 2.7 mm arthroscope is available with a working length of 11 cm. Its shorter length is an advantage over the 2.7 mm MPRT for arthroscopy making handling the telescope in small joints much easier. The only other advantage of this telescope over the 2.4 mm arthroscope is that it is more robust with less chance of breakage, especially when used by a beginner. Disadvantages are that the optics are not as good as either the 2.4 mm arthroscope or the 2.7 mm MPRT and the blunt obturator design makes portal placement more difficult. The 1.9 mm arthroscopes are available in 10 mm and 6.5 mm lengths. The smaller size of these telescopes is an advantage for use in smaller joints such as the radiocarpal joint, tibiotarsal joint, and for use in small dogs or cats. Their disadvantages are that they are fragile breaking more easily, the field of view is significantly smaller increasing the difficulty of joint visualization, and the optics are not as good making them less effective for documentation purposes. Four-millimeter diameter telescopes are also available for use in small animals but are too large for most joints in most patients. A 4 mm arthroscope has been used in the stifle joint of larger dogs and in the shoulder joint in giant breeds. Four-millimeter telescopes are available in lengths of 18 cm and a shorter 12 mm version. A 4.0 Endocameleon arthroscope is a new addition to the armamentarium for large joint arthroscopy with a variable direction of view from 15° to 90°. The shorter length arthroscopes have another advantage in that they can be held in a pistol grip fashion with the surgeon’s index finger on the skin at the portal site to accurately and easily maintain a constant depth of telescope insertion. This greatly reduces the number of times the field of view is lost because the telescope is inserted too deep or the telescope is inadvertently pulled

out of the joint. This is particularly important for beginners. A significant advance in telescope technology is that most telescopes are now autoclavable. The autoclavable telescopes are labeled as autoclavable. This greatly facilitates instrument turnaround and practice efficiency.

1.2.2  Sheaths and Cannulas 1.2.2.1  Telescope Sheaths

Arthroscopes are used with a cannula or sheath to protect the telescope and provide a channel for fluid inflow (Figure 1.4 and Table 1.4). A specifically matched sheath is required for each specific telescope size. Telescope sheaths come with a sharp trocar and a blunt obturator. The blunt obturator is preferred because it causes less damage to joint cartilage when establishing the telescope portal. Sheaths for the smaller telescopes used in small animal practice typically have a single fixed stopcock with a Luer lock connector used for fluid inflow. Cannulas are also available with two stopcocks and stopcocks that rotate on the cannula. All sheaths have a locking mechanism that fixes the cannula to the telescope. This locking mechanism is very important as it protects the telescope from being damaged. When locked in place, the distal tip of the telescope is aligned with the distal tip of the sheath and this protects the distal lens of the telescope. More importantly, when the telescope is locked in place, the sheath protects against excessive bending stresses along the telescope shaft. This locking mechanism also creates a watertight seal at the proximal end of the sheath so that irrigating fluid flows into the joint. It is very important that the telescope is properly locked in place for fluid flow, to prevent interference of the tip of the cannula with the visual field, and most importantly, to prevent telescope damage. The locking mechanism of telescope cannulas has evolved over time from a rotating ring to a sliding box and, more recently, to a snap-in design with springloaded locks (Figure 1.5). The rotating ring is the traditional coupling mechanism being the oldest and simplest configuration for locking the telescope to the cannula. This design works well, has withstood the test of time for dependability, and is easy to use. The sliding box or automatic lock design is slightly easier to use, is more secure than the traditional coupling mechanism, but can become hard to slide over time eventually sticking and becoming inoperable. The snap-in coupling is the most recent locking mechanism, is the easiest to use, and provides secure attachment of the telescope to the cannula.

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Figure 1.4  Arthroscope sheaths with blunt obturators from left to right: blunt obturator for the 2.7 mm long arthroscope or MPRT, sheath for the 2.7 mm long arthroscope or MPRT telescope with a single rotatable stopcock and with a blunt obturator inserted, blunt obturator for the 2.4 mm telescope, sheath for the 2.4 mm arthroscope with a single fixed stopcock, blunt obturator for the short 2.7 mm arthroscope, sheath for the short 2.7 mm arthroscope with a single rotatable stopcock, an operating cannula with a blunt obturator in place, sheath for the1.9 mm arthroscope with a single fixed stopcock and with a blunt obturator inserted, and an egress cannula with a blunt obturator in place. The telescope cannulas in this image all have the snap-in coupling design. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Table 1.4  Telescope sheaths used for small animal arthroscopy.

a

Arthroscope

Sheaths part number (Karl Storz)

Obturators part number (Karl Storz)

4.0 mm/18 cm/30° (64 230 BWA)

64124AR

65127BS/BT

4.0 mm/12 cm/30° (64 728 BWA)

64126KR

64129BT

4.0 mm Endocameleon/18 cm (28 731 AE)

28 136 EC

28126 BC/BT

2.7 mm/18 cm/30° (64 029 BA)

a

63122 AS/AB

Snap in

28132S

28132BC/BT

2.7 mm/11 cm/30° (67 208 BA)

a

64147 BS/BT

Snap in

26133DS

28133BC

2.4 mm 10 cm/30° (64 300 BA)

a

64303 BU/BV

Snap in

28303BN

28302BU/BV

64128 AR 64147 BN 64303 BN

1.9 mm/11 cm/30° (64 301 BA)

64 302 BN

64302 BS/BT

1.9 mm/6.5 cm/30° (28 305 BA)

a

64306 BS/BT

Snap in

64306BN

64306BS/BT

28306 BN

 Shown in Figure A I 4.

1.2.2.2  Operative Cannulas

Operative portals are established with a cannula (Figure 1.6 and Table 1.5) or using a free passage technique where instruments are placed through the soft tissues overlying the joint without using a cannula. Conflicting opinions exist about which technique is

best, but both are effective with each having its indications, advantages, and disadvantages. When a cannula is used, access for instrumentation is established and ­maintained by placing the cannula into the joint at the  operative portal site. This technique has the advantage of facilitating reinsertion of instruments.

1.2  ­Instrumentation and Equipmen

Figure 1.5  Locking mechanism designs for attaching sheaths to telescopes. From left to right: A snap-in coupling mechanism with spring-loaded locks, a traditional rotating ring locking mechanism, and an automatic lock. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Figure 1.6  Operating cannulas for arthroscopy from left to right: a 5.5 mm operating cannula with its blunt obturator in place, a 4.5 mm operating cannula with a blunt obturator, a 2.5 mm operating cannula with a sharp trocar in place, and a 3.5 mm operating cannula with a blunt obturator. Rubber gaskets for these cannulas are used when indicated. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

The ­disadvantages of operative cannulas are that they limit the size of instruments that can be placed into the joint and the size of tissue fragments that can be removed. Operative cannulas can interfere with instrument manipulation because of small joint size with very short distances between the joint capsule and operative sites. Operative cannulas are also

­ ifficult to keep in place tending to come out with d instrument and tissue removal. For free passage of instruments without a portal cannula, joint access is created with a sharp incision into the joint using a no. 11 blade followed by blunt dissection through tissues overlying the joint using a curved mosquito hemostat. Instruments are passed into the joint directly through the tissues. This technique has the advantages of allowing passage of larger instruments, removal of larger pieces of tissue, eliminating interference of the cannula during operative instrument manipulation, and eliminating the problem of the cannula being displaced by removal of instruments and tissues. The primary disadvantage of this technique is increased difficulty of instrument reinsertion through the operative portal. A combination of the two techniques has been employed using the one that best fits the current procedure or stage of the procedure. Operative cannulas that have been used for small animal arthroscopy are 2.5 mm diameter for 2.0 mm instruments, 3.5 mm diameter for 2.8 mm instruments, 4.5 mm diameter for 3.5 mm instruments, and 5.5 mm diameter for 4.8 mm instruments. Cannulas come with sharp trocars or blunt obturators for insertion and are supplied with rubber gaskets to prevent fluid leakage when instruments are in place. If increased pressure in the joint is needed for a specific procedure, the gaskets are used. There are no valves or stopcocks in these cannulas,

Table 1.5  Operating cannulas used for small animal arthroscopy. Cannula diameter ( mm)

Instrument size ( mm)

Cannula part number (Karl Storz)

Obturator part number (Karl Storz)

5.5

4.8

a

64146 XS/XT

4.5

3.5

a

64169 XS/XT

3.5

2.8

a

64183 XS/XT

2.0

a

64302 XS/XT

2.5 a

 Shown in Figure A I 6.

64146 X 64169 X 64183 X 64302 X

7

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1  Introduction and Instrumentation

so they do not hold fluid in the joint when an instrument is not in place. Gaskets increase the resistance of instrument insertion or removal and increase the tendency for cannulas to be removed when instruments are withdrawn. Operative cannulas are positioned under observation with the arthroscope to prevent intra-articular damage. 1.2.2.3  Egress Cannulas

A site for outflow of fluid from joints is required. Fluid flow is necessary to maintain a clear visual field during arthroscopy, to provide joint distension, and for removal of debris created with operative procedures. Low outflow resistance achieved with an egress cannula will maintain adequate fluid flow without excessive pressure. Egress cannulas for small animal arthroscopy are 2.2, 3.2, and 4.5 mm in diameter (Figure 1.7 and Table 1.6). The larger two sizes have multiple side holes in the distal 1–2 cm of the cannula. This allows free access of fluid to the cannula and minimizes the possibility of occlusion. A Luer connector at the proximal or outside end of the cannula allows connection of an ­outflow line to direct fluid away from the operative field. The two larger sizes have a stopcock to control the rate of fluid egress. The two larger egress cannulas come with either a sharp trocar or a blunt obturator for inserting the cannula into the joint. Intra-articular tissue damage is minimized by observing cannula placement with the arthroscope.

Figure 1.7  Egress cannulas for small animal arthroscopy from bottom to top: a 2.2 mm egress cannula without a stopcock, a 3.2 mm egress cannula with a stopcock, and a 4.5 mm egress cannula with a stopcock. The 3.2 mm cannula is shown with a blunt obturator, and the 4.5 cannula is shown with a sharp trocar. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Table 1.6  Egress cannulas used for small animal arthroscopy. Cannula Cannula part Obturator part number diameter ( mm) number (Karl Storz) (Karl Storz)

a

4.5

a

28146 TO/TS

3.2

a

64146 QO/28146QB

2.2

a

64146RO

64146 TT 64146 T 64146 R

 Shown in Figure A I 7.

Placement of an egress cannula is difficult in some smaller joints because of inadequate space within the joint or inadequate room for portal placement sites. In these cases, and for simple diagnostic procedures in larger joints, a 20-gauge hypodermic needle is used for an egress site. Egress through operative portals is used in many joints for many operative procedures. This has the advantage of simplifying the procedure by eliminating the step of egress cannula placement. Another advantage of using operative portals for egress is that when egress is close to the operative site debris from the procedure flows directly out of the joint rather than through the joint to a distant egress portal. This decreases the potential for leaving operative debris in the joint.

1.2.3  Operative Hand Instruments The number and variety of hand instruments available for arthroscopy are extensive, but fortunately very few hand instruments are needed to perform operative arthroscopy for most of the common conditions seen in small animals. A basic set of arthroscopic hand instrumentation (Table 1.7 and Figure 1.8a) includes 2.0, 2.5, 3.5, 4.0, and 5.0 mm arthroscopic rongeurs (Figure 1.8b); 2.3 and 3.5 mm arthroscopic grasping forceps (Figure  1.8c); 0°, 30°, and 70° microfracture chisels (Figure  1.8d); 0, 2–0, 3–0 and 4–0 straight curettes (Figure 1.8e); 3–0, 4–0, and 5–0 curved/angled curettes; 1 and 2 mm hook probes (Figure  1.8f); and changing rods or switching sticks (Figure 1.8g). Standard surgical instrumentation and supplies used for arthroscopy (Table  1.8) include curved mosquito hemostats with and without teeth; 20 gauge 1″ and 1.5″ hypodermic needles; 20 gauge 2.5″ or 3.5″spinal needles; no. 11 scalpel blades; 3 and 12 cc syringes; a 3-way stopcock; liter containers of saline or Ringers solution; IV administration sets; IV extension sets; pressure cuffs for fluid bags, and a set of standard orthopedic operative instruments. This set of instruments is adequate for performing OCD surgery in all joints, for coronoid process revision,

1.2  ­Instrumentation and Equipmen

(a)

(b)

Figure 1.8  Operative hand instruments for small animal arthroscopy: (a) A set of small animal arthroscopy hand instruments that are sufficient for the majority of operative procedures being performed today. On the top row from left to right: 2.0 mm grasping forceps, 2.8 mm SilGrasp cartilage grasping forceps with straight spoon-shaped jaws, 2.8 mm SilGrasp straight Alligator grasping forceps, 3 mm SilGrasp straight Alligator grasping forceps, 3.5 mm Blakesley rongeurs, and 4.0 mm Blakesley rongeurs. On the bottom row from left to right: 30°, 0°, and 70° microfracture chisels; 0, 2–0, 3–0, and 4–0 curettes; 1.0 mm and 2.0 mm graduated probes; a 5–0 delicate curette, and two switching sticks or changing rods. Instrument details are presented in individual groups. (b) Rongeurs and grasping forceps from left to right, Blakesley 4.0 mm rongeurs, Blakesley 3.5 mm rongeurs, 2.8 mm SilGrasp cartilage grasping forceps with straight spoon-shaped jaws, and 2.0 mm grasping forceps with spoon-shaped jaws. (c) Grasping forceps from left to right: 2.8 mm SilGrasp alligator grasping forceps and 3.5 mm SilGrasp alligator grasping forceps. (d) Microfracture chisels from top to bottom: 0°, 30°, and 70°. (e) Straight curettes from left to right: 0, 2–0, 3–0, 4–0, and 2.3 mm straight curettes. (f) Graduated probes: a 2.0 mm graduated hook probe at the top and 1.0 mm graduated hook probe at the bottom. (g) Changing rods or switching sticks: a 2.8 mm diameter × 23 cm long changing rod on top and a 3.5 mm diameter × 23 cm long changing rod on the bottom. A 2.0 mm diameter × 15 cm changing rod is also available. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

9

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1  Introduction and Instrumentation

(c)

(d)

(e)

(f)

Figure 1.8  (continued)

(g)

1.2  ­Instrumentation and Equipmen

Table 1.7  Hand instruments used for small animal arthroscopy. Instruments

Part number (Karl Storz)

Hook probes 1.0 mm

28145SN

2.0 mm

64145S

Arthroscopic rongeurs 2.0 mm

64302 L

2.5 mm

634824

4.0 mm

456502

5.0 mm

64149 RL

SilGrasp alligator grasping forceps (Figure A I 8C) 2.8 mm

28572AG

3.5 mm

28571AG

Straight curettes 2-0

64620

3-0

64630

4-0

64640

5-0   Miltex

19-700

Curved curettes 3-0   Miltex

26-1737

4-0   Miltex

26-1738

5-0   Miltex

26-1739

Exchange rods or switching sticks 2.0 mm × 15 cm

64302 W

2.8 mm × 23 cm

64124 BZ

Micro fracture chisels 0°

64728 CF

30°

64728 CG

70°

64728 CH

Leipzig stifle retractor

Table 1.8  Additional supplies used for small animal arthroscopy No. 11 scalpel blades 20 gauge 1″ and 1.5″ hypodermic needles 20 gauge 2.5″ or 3.0″ spinal needles 3 cc syringes 12 cc syringes 3-way stopcock Liter containers of saline or Ringers solution IV administration sets (Hespera life shield 12672-28) IV extension sets (Hespera life shield 12656-28) Pressure cuffs for fluid containers Curved mosquito hemostats without teeth Curved mosquito hemostats with teeth A basic set of orthopedic surgery instruments

tion to open the joint space providing more room for instrument placement and tissue manipulation. The Leipzig stifle distractor (Figure  1.9 and Table  1.7) was designed specifically for this purpose. It is typically not needed for diagnostic examination of the stifle. Some minor surgical procedures in loose joints can be performed without the distractor, but its application is indicated for most operative procedures. It is attached to the distal femur and proximal tibia with fixation screws supplied with the distractor or bone pins can be used. This instrument provides for distal distraction of the tibia from the femur to open the joint space and cranial displacement of the tibial plateau to increase exposure of the menisci.

64820 LSD

bicipital tendon transection, anconeal process removal, meniscal release, and bone chip removal. Additional hand instruments that are helpful include larger rongeurs and grasping forceps, open curettes, a selection of arthroscopic knives, and curved meniscal resection forceps. When starting arthroscopy where minimally invasive completion of procedures may not always occur, a set of standard operative instruments is needed including all those needed for completion of the surgical procedure should conversion to open arthrotomy be indicated. Operative procedures in the stifle joint, especially meniscectomy, are greatly facilitated with stifle distrac-

Figure 1.9  The Leipzig stifle distractor. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

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1  Introduction and Instrumentation

1.2.4  Power Instruments 1.2.4.1  Power Shavers

Power-operated shavers are a great asset to operative arthroscopy and are used to remove cartilage, bone, and soft tissues (Figure 1.10 and Table 1.9). These units greatly speed operative procedures, produce a better result with a smoother surface after tissue removal, and decrease the amount of debris left in joints. Shavers are not absolutely necessary for some of the basic operative procedures in small animals which can be performed effectively with hand instruments. Using a powered shaver when first learning to perform arthroscopy is not recommended because the potential for severe joint and instrument damage is greatly increased by putting power tools in the hands of the inexperienced operator. Extensive damage can be caused by a single rotation of the shaver when the blade is inappropriately placed. Any surgeon getting into arthroscopy needs to consider purchasing a power shaver at the time of acquiring initial instrumentation or as a planned addition. Complex procedures performed by experienced surgeons are greatly facilitated with a shaver and an appropriate selection of blades.

Table 1.9  Power instruments used for small animal arthroscopy.

Instrumentation

Part number (Karl Storz)

Power shaver Unidrive SL III Arthro(Console)

287230 2

Drillcut-X Arthro(Handpiece)

28200 DX

Multifunction Handpiece

287210 36

Shaver blades(70 mm Length) Aggressive cutter 3.5 mm

28206 ABS

Aggressive cutter 2.5 mm

28206 AAS

Full radius resector 3.5 mm

28206 CBS

Full radius resector 2.5 mm

28206 CAS

Aggressive full radius resector 3.5 mm

28206 DBS

Aggressive full radius resector 2.5 mm

28206 DAS

Small round burr 3.5 mm

28206 FBS

Small Round Burr 2.5 mm

28206 FAS

Two pedal foot switch

200168 31

Three pedal foot switch

200128 32

Bipolar radiofrequency MITEK VAPR/VAPR VUE Fluid pumps Endomat select

Figure 1.10  The Unidrive S III SCB Console with the multifunction orthopedic handpiece for orthopedic surgery and the Drillcut-X Arthro handpiece for arthroscopy. Both of these handpieces are appropriate for use in small animal practice. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

UP210

Vet software (must be specified or device does not function)

UP609

Irrigation tubing set

031523-10

An example of damage caused by an inexperienced arthroscopic surgeon was in a training session with ­surgery residents at an academic institution. This was their first exposure to arthroscopy and the instrumentation was new. During this training session, the end of the telescope was ground off with the shaver destroying the instrument before it was ever placed in a patient. Caution is required in the use of power tools by all of us but particularly for beginners. A series of small shavers originally designed for maxillofacial surgery was initially applied for small animal arthroscopy. These shaver handles were much smaller than available human “small joint” shavers and their size was much more suitable for small animal arthroscopy. Small joint shaver handles have evolved into more suitable instruments for our use. These small handpieces have less torque than the standard larger handpieces which has been a complaint from some surgeons, but this lower torque is actually an advantage in the small spaces where we work. The newest small handpiece, the Drillcut-DX ARTHRO shaver handpiece

1.2  ­Instrumentation and Equipmen

(a)

Figure 1.11  The Drillcut-X ARTHRO shaver handpiece. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

(Figure 1.11) is smaller and lighter with improved ergonomics, with a maximum speed of 8000 rpm, more torque, and an easier to clean design. Larger handpieces have greater maximum speeds of up to 15 000 rpm and are more difficult to use in our small joints. They also have significantly more torque which is a disadvantage as the blade can catch sending the shaver across the joint potentially causing damage to the joint or telescope. A wide variety of blade types and sizes are available for the Drillcut-DX ARTHRO shaver handpiece for different applications. Shaver blades include burrs (2.5–6.5 mm diameter and 70–180 mm long) for removing bone and cartilage, aggressive cutters, and full radius aggressive cutters (2.5–5.5 mm diameter and 70–180 mm long) for removing soft tissue and cartilage, and full radius resectors with smooth cutting edges (2.5–5.5 mm diameter and 70–180 mm long) for removing soft tissue. These shaver blades come in reusable and disposable versions. Reusable versions are not recommended as they become dull too fast, break too easily, and are far more expensive than disposable blades. Disposable versions are recommended because they are less expensive, are still reusable several times, and can be autoclaved. Lengths of 70, 120, and 180 mm are available with some types in curved versions. A limited selection of 70 mm long shaver blades is available in 2.5 and 3.5 mm diameters (Figure  1.12). These short small diameter blades are ideal for the small size of the joints encountered in our patients. The longer blades can be used with the Drillcut-DX ARTHRO handpiece with much wider selection types but are more cumbersome to use. Shaver blades are cannulated so that debris from the cutting process is aspirated out through the blade as shaving is performed. Suction is used with shavers to facilitate debris removal and to pull soft tissues into the blade to enhance the soft tissue cutting process. Larger sized blades speed soft tissue removal in procedures such as cruciate ligament debridement but are more difficult to use in small joints. Smaller blades are easier to use, are needed to access small joint spaces such as for meniscus debridement, but remove tissue more slowly, and are more susceptible to occlusion with tissue debris.

(b)

(c)

(d)

Figure 1.12  Single-use shaver blade types commonly used in small animal arthroscopy: The blades shown here are those available in 70 mm length, 2.5 mm and 3.5 mm diameters, which are ideal for use in the small joints of our patients. (a) A full radius resector with smooth blades on both cutting surfaces. (b) An aggressive full radius resector with a serrated blade on the inner cutting surface and a smooth blade on the outer cutting surface. (c) An aggressive cutter with both blades serrated. (d) A round burr. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

A selection of blade sizes and types is recommended to maximize shaver function. The shaver control unit has the capability to drive all the arthroscopy shaver units, from 6000 to 15 000 rpm, and also to power a multifunction handpiece for open orthopedic surgery applications. The console has a large multicolor touchscreen providing easy determination of instrument settings, intuitive instrument management for changing speeds or rotation direction, and allows changing settings from hand switch to foot switch control. With the small size of the joints that we operate, foot switch control is recommended. Using a foot switch rather than hand controls on the handpiece allows the shaver to be started and stopped without changing grip position on the handpiece. Having to change hand or finger position is difficult to do without moving the handpiece or especially the tip of the shaver blade. Inadvertent movement of the shaver tip by only a few millimeters or a few degrees rotation can cause damage to the tissues or to the arthroscope. Foot switches are available in three-pedal (Figure  1.13a) and two-pedal

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(a)

(b)

gravity, pressure cuffs on fluid bags, or with a mechanical arthroscopy pump. Outflow is controlled with the level of suction applied to the system and with a lever on the shaver handpiece. The shaver blades are hollow and are designed to have suction applied so that fluid is aspirated through the blade and handpiece to remove bony debris from the joint. With soft tissues in the joint suction through the shaver, in addition to removing debris, also functions to pull tissue into the shaver blade facilitating cutting and removal. Too little flow allows shaver produced bone fragments to accumulate in the joint (Video 1.2) interfering with the visual field and increasing debris that can be left in the joint. Too much suction pulls air into the joint that can interfere with the visual field (Video 1.3). When inflow and suction are balanced neither occurs and shaver function is optimized (Video 1.4). Many cases proceed with little problem, but others require constant adjustment. 1.2.4.2  Radiofrequency/Electrocautery Instrumentation

Figure 1.13  Foot switches for use with the shaver system. (a) The three pedal shaver foot switch. The left pedal is for unidirectional rotation to the left (counterclockwise), the right pedal is for unidirectional rotation to the right (clockwise), and the center pedal is for oscillating rotation. (b) The two pedal shaver foot switch. The left pedal is for unidirectional rotation to the left (counterclockwise), and the right pedal is for unidirectional rotation to the right (clockwise). To achieve oscillating rotation, both pedals are depressed. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

versions (Figure 1.13b). The three-pedal system is larger but is easier to use because each pedal has one function with the left pedal running the shaver in one direction, the right pedal running the shaver in the other direction, and the center pedal activating the oscillating rotation function. With the two pedals system, each direction of rotation is controlled by depressing one of the foot pedals but to achieve oscillating rotation both pedals need to be depressed at the same time making control of this function more difficult. Another issue with power shavers is balancing liquid inflow and outflow. Inflow is controlled with

Monopolar or bipolar radio-frequency instrumentation is used to cut tissue, cauterize bleeding vessels, and for removal of tissue by vaporization. The most common use of radio-frequency is for ablation of the fat pad and villus synovial reaction to improve visualization in the cruciate compromised stifle joint, for cranial cruciate ligament debridement or removal, for medial meniscal release by transection of the caudal meniscotibial ligament, and for partial or complete meniscectomy. Radiofrequency was used in the shoulder joint for thermal modification of medial soft tissue structures, but this application has fallen into disfavor and is no longer recommended. Radiofrequency is also used for transection of the bicipital tendon when indicated. Ablation of villus synovial proliferation with radiofrequency is beneficial in any joint to improve the visual field by removal of excessive synovial tissue. Specific instrumentation designed for arthroscopy is available in bipolar configuration (Figure  1.14 and Table  1.9). Multiple handpiece tip configurations and sizes are available to facilitate access to structures within joints and for different tissue effects (Figure 1.15). The power settings of these units are automatically set for the handpiece employed but are also manually adjustable for different applications. The original arthroscopy specific bipolar radio-frequency unit is still in use but is no longer supported. Evolution of this system through several generations has occurred with significant improvements including better heat management and integrated suction (Figure 1.16).

1.2  ­Instrumentation and Equipmen

Standard monopolar radio-frequency surgery units can be modified for intra-articular use by purchasing specific arthroscopy tips. This approach is effective for cutting and for cauterizing but is not effective for ablation of large quantities of tissue.

1.2.5  Irrigation Fluid and Management Systems

Figure 1.14  A Mitek VAPR II bipolar arthroscopic radiofrequency control unit used in the author’s practice. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 1.15  A selection of handpieces for use with the Mitek VAPR II bipolar radiofrequency unit. Multiple handpiece configurations are available. Shown here from top to bottom are a 3.5 mm side effect electrode (center in insert), a 3.5 mm hook electrode (left in insert), and a 2.3 mm short side effect electrode (right in insert). Additional electrode configurations termed end effect in 3.5 mm and 2.3 mm sizes, a 2.3 mm wedge electrode, and a 3.5 mm thermocouple temperature-controlled electrode are also available. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 1.16  A Mitek VAPR VUE bipolar arthroscopic radiofrequency unit with handpiece and two pedal foot switch. Source: Photo courtesy of DePuy Mitek Sports Medicine division of Johnson & Johnson.

The optical field for arthroscopy is established and maintained by irrigating the joint with fluid. Three different techniques are used for maintaining fluid flow; gravity flow using liter containers of fluid placed above the patient with an IV set connected to the fluid portal on the telescope cannula; pressure assisted flow with a manual pressure cuff added to the gravity flow system; or an automatic mechanical arthroscopic infusion pump. Ingress fluid flow through the telescope cannula assists in keeping a clear view by washing blood and debris away from the lens of the telescope out of the visual field. Continuous drainage provided by an egress needle, egress cannula, or through the operative portal allows for continuous fluid flow. A high flow low pressure system is effective in maintaining a clear visual field while decreasing the potential for periarticular fluid accumulation. This is achieved by decreasing outflow resistance rather than by increasing inflow pressure. Overzealous infusion of fluids results in collection of fluid in the periarticular and subcutaneous tissues that can interfere with joint examination by compressing the joint capsule. Excessive fluid pressure can cause rupture of the joint capsule. 1.2.5.1  Irrigation Fluids

Lactated Ringer’s solution, Ringer’s solution, and physiologic saline solution are the most commonly used fluids for arthroscopy. There is no clear agreement on which is the preferred solution and research has given conflicting results. This debate had been well studied prior to publication of the Arthroscopy chapter of first  edition of Veterinary Endoscopy for the Small Animal Practitioner (McCarthy 2005; Andrews and Timmerman  1997). Some of the studies done at that time showed no difference in effect on cartilage metabolism of physiologic saline, lactated Ringer’s solution, and sterile water (Arciero et  al.  1986). Other studies showed that sterile water has more adverse effect than lactated Ringer’s solution and that lactated Ringer’s solution has more adverse effect than saline (Bert et al. 1990; Reagan and McInerny 1983). Whereas other studies have shown that Ringer’s solution is more detrimental than sterile water (Gradinger and Träger 1995; Jurvelin and Jurvelin 1994). An evaluation of ionic (lactated Ringer’s and sterile water) and nonionic solutions

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(Sorbitol, Mannitol, and Dextran 40) showed the least effect on mechanical properties and least proteoglycan  loss with nonionic solutions (Gradinger and Träger 1995). A review of this debate at that time concluded that: “The author is unaware of any deleterious effects of normal saline solution. At the author’s institution, normal saline is the most economical solution available.” (Andrews and Timmerman  1997). A recent systematic review of the literature from 1946 to 2018 looking at this question did not provide any additional conclusive answers and suggested that additional human studies are needed (Sardana et al. 2019). There is currently no clear scientific answer to the question as to which solution is best for arthroscopy. In a practical sense, there are no proven clinical disadvantages or adverse effects of using lactated Ringer’s solution, Ringer’s solution, or normal saline. Any crystalloid solution suitable for IV use can be used for arthroscopy although solutions containing glucose are not recommended because of the sticky residue. Since normal saline and lactated Ringer’s solutions are readily available, inexpensive, and there are no valid clinical arguments against their use, they are the solutions currently used for arthroscopy. One, three, and five-liter bags of sterile IV solutions are available and are suitable for arthroscopy. Larger bags have the advantage of requiring less frequent container changes during procedures than smaller bags. With experience, most procedures are completed with one liter or less of fluid making the need for larger bags uncommon. Larger bags are more cumbersome to handle than one-liter bags. One-liter containers are also less expensive per liter than their larger counterparts. 1.2.5.2  Gravity Flow

This is the simplest, easiest, and least cumbersome technique for maintaining irrigation and works well for most diagnostic arthroscopy and many of the basic operative procedures. The technique uses IV fluid bags connected to an intravenous fluid administration set that is then connected to the inflow port in the arthroscope cannula. Air is bled from the IV line prior to use to minimize air bubbles that will interfere with the visual field. Intravenous administration sets are available with a filter in the cap on the patient end of the line (Figure 1.17) that allows air to escape and prevents liquid leakage. The fluid bag is hung above the patient, and the intravenous administration set flow controls are opened fully. The stopcock on the telescope cannula is then used to start and stop fluid flow. Fluid pressure and joint distension are controlled by the level the bag is placed above the joint. The rate of fluid flow is con-

Figure 1.17  An intravenous fluid administration extension set with a filter cap that allows the escape of air but not liquid facilitating bleeding irrigation lines for arthroscopy. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

trolled by inflow pressure and by egress resistance. A high flow low pressure system is effective in maintaining a clear visual field while decreasing the potential for periarticular fluid accumulation. This is achieved by decreasing outflow resistance rather than by increasing inflow pressure. 1.2.5.3  Pressure Assisted Flow

Gravity flow is adequate in most cases for diagnostic and beginning operative arthroscopy. A pressure cuff on the fluid bag can be added to the system to increase pressure and flow when needed. A manually inflatable pressure cuff is placed on the fluid bag and inflated to create adequate pressure. This system is inexpensive and is easy to set up and use. Disadvantages are that pressure needs to be repeatedly added to the bag during the procedure, changing bags can be cumbersome, and the potential for periarticular fluid accumulation is increased if too much pressure is applied to the cuff. Using two fluid bags with two pressure cuffs facilitates changing bags because when one bag is empty, the fluid line is quickly and easily changed to the second bag. The pressure cuff from the empty bag is then transferred to a new full bag so that it is ready for the next exchange. Many operative procedures do not require more than one liter of fluid but preparation of the second bag with the pressure cuff in place minimizes the time for bag replacement when it is needed. 1.2.5.4  Mechanical Arthroscopy Fluid Pumps

Mechanical pumps that automatically manage intraarticular fluid pressure and flow are an asset to operative arthroscopy (Figure 1.18 and Table 1.9). They are

1.2  ­Instrumentation and Equipmen

and care of the tubing is critical for proper pump function. All air must be removed from the system as the presence of air interferes with pressure sensing causing the pump to cycle unnecessarily. The tubing is designed to allow attachment of two fluid bags simultaneously facilitating uninterrupted fluid availability.

1.2.6  Video System Tower

Figure 1.18  ENDOMAT SELECT UP 210, Automatic mechanical arthroscopic fluid pump. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

A video endoscopy system is absolutely essential for arthroscopy. The system is assembled in a video tower which is a movable cart or cabinet on wheels containing the components of the video system needed for performing arthroscopy or other video endoscopic procedures (Figure 1.20 and Table 1.10). The necessary

also an added expense and increase the complexity of operating room setup. Although not necessary for diagnostic arthroscopy or for basic operative arthroscopy, they become more important as complexity of procedures increases with their benefits increasing and advantages of having a fluid pump becomes more significant. These pumps have adjustable pressure and flow settings that are used to balance pressure and flow for each specific joint and case. Pressures of 50 cm of water or less are recommended for small animal arthroscopy. Once set the pressure is maintained automatically by the pump varying fluid flow. Special inflow tubing is required for use with these pumps (Figure 1.19). Setup

Figure 1.19  ENDOMAT irrigation tubing setup for use for arthroscopy with the ENDOMAT SELECT UP 210. The tubing is designed to allow attachment of two fluid bags simultaneously facilitating uninterrupted fluid availability. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Figure 1.20  A video tower that is appropriate for small animal arthroscopy and other endoscopy applications in small animal private practice. Shown from top to bottom: 17” flat screen high definition monitor, a keyboard, on the next shelf on the right a laparoflator, a 300-W Xenon light source, and a high definition camera control box with a built-in capture system. On the left side of this shelf is a 30-W diode surgical laser. The next shelf down has an arthroscopic shaver control box on the left side with the foot switch for the laser on the right side. On the bottom shelf, a LigaSure is stacked on top of a VAPR II arthroscopic radio-frequency unit. Carbon dioxide tanks are fastened to the left side of the cart with a pole for hanging fluid bags. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Table 1.10  Video system components used for small animal arthroscopy. Video component

Part number (Karl Storz)

Video cameras Image I S H3-link rigid TC 300 endoscopy full HD link module Image I connect console

TC 200

Image I S three chip full HD camera head

TH 100

Light sources Xenon Nova(175 W)

691315 01

Xenon Nova 300(300 W)

201340 01

LED Nova 150(150 W)

201612 01

Power LED 175(175 W)

201614 01-1

Power LED 300(300 W)

TL 300

Fiber optic light cables Many lengths and diameters

495/69495

Monitors Any high quality flat-screen monitor Documentation AIDA with Smartscreeen    WD 350 Compact one piece portable system Tele PAC VET X LED    RP 100 Tele cam one-chip camera head    20 212 030/20212130

components of a video system are a video camera, video monitor, light source, and a cart or cabinet on wheels. An arthroscopic power shaver, mechanical fluid pump, and radio-frequency unit are included in the tower so that setup for procedures is quick and easy. Additional optional components include video recording or capture devices and, for soft tissue applications, a diode or holmium laser, an insufflator for laparoscopy, plus a vessel sealing device are needed. Larger more elaborate carts are available that hold more instrumentation and that have positioning arms for the monitor, but the tower shown has functioned well (Figure 1.21). 1.2.6.1  Video Camera

Specifically designed cameras for arthroscopy and minimally invasive surgery are essential for arthroscopy (Figure 1.22). The camera head attaches directly to the arthroscope eyepiece to create a one-piece operating system (Figure  1.23). Endoscopic camera heads are very small and lightweight because the majority of electronic circuitry for the system is in a control unit box that is out of the operative field in the video system

Figure 1.21  An elaborate endoscopy tower with two flat-screen monitors on arms and more shelf space for additional instrumentation modules. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Figure 1.22  An IMAGE 1 FULL HD Three Chip Camera Head H3-Z. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

tower (Figure 1.24). An alternative camera system for limited space situations and for mobile applications is a Tele Pack. This self-contained system includes a light source, camera control box, monitor, and a capture system in a single small suitcase-sized unit (Figure 1.25).

1.2  ­Instrumentation and Equipmen

Figure 1.25  A Tele Pack Vet X LED self-contained endoscopy video system with a camera control box, LED light source, monitor, and capture system in a single small suitcase-sized box. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

provide an excellent image. Three chip cameras and high definition cameras have higher resolution and better color separation but are only necessary for obtaining publication-quality images. A significant recent advance in camera technology is that they are available as autoclavable versions greatly speeding instrument turnaround. Figure 1.23  The IMAGE 1 HD camera head coupled to an arthroscope while performing elbow arthroscopy. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 1.24  An IMAGE I FULL HD camera box and head with an Image 1 connect capture module. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

This system uses a standard definition single-chip camera with image quality that is more than adequate for small animal arthroscopy. These cameras are lightweight, compact, connect directly to the telescope, and

1.2.6.2  Video Monitor

The medical-grade video monitors previously recommended and considered to be necessary for effective video endoscopy are no longer needed and have been replaced by flat-screen monitors (Figures 1.20 and 1.21). The added expense of a medical-grade monitor is no longer required. The decreased cost for monitors with flat-screen technology also allows use of more than one monitor in the operating room. The currently recommended operating room setup uses two monitors, one on the tower, and one mounted on a wall at an appropriate location for the operating room. A wireless transmission system connects the remote monitor to the tower system eliminating the need for wired connections. This arrangement eliminates the problem of monitor placement for complex procedures where more than one monitor position is needed. 1.2.6.3  Light Source

A good quality light source and fiberoptic light guide cable are required for arthroscopy. Halogen was the initial light source used when fiberoptic light transmission was developed for endoscopic use. Xenon light sources (Figure 1.26) have replaced halogen and have been the preferred technology for arthroscopy for many years.

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Figure 1.27  A 300-W LED light source. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

Figure 1.26  A Xenon Nova 300-W light source. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

They are available in 175 and 300-W sizes. Xenon light sources are much brighter and provide a light wavelength closer to natural light giving tissues truer color. The major disadvantage of Xenon is the cost of bulb replacement and its short bulb life expectancy compared to other light sources. Newer diode light sources (Figure 1.27) are available that produce light comparable in wavelength to Xenon with less energy use and a bulb life expectancy in the 30 000 hours range. They are currently more expensive than Xenon light sources. Flexible fiberoptic light guide cables are used to connect the light source to the telescope (Figure  1.28). These light guide cables are available in diameters from 2.5 to 4.8 mm and lengths from 180 to 320 cm. Smaller light guide cables are recommended for smaller telescopes and larger light guide cables for larger telescope diameters. Multiple adaptors are available to allow connection to endoscopes and light sources from many manufacturers. 1.2.6.4  Documentation Equipment

Diagnostic and operative arthroscopy can be performed without a capture device. When a capture device is used, they are incorporated into the video system tower, so they are ready whenever the system is used. Camera control units are also available with capture systems built into the control unit box as an ICM module

Figure 1.28  Light guide cable for connecting the light source to the light post on rigid endoscopes. Source: Photo courtesy of KARL STORZ: © KARL STORZ SE & Co KG, Germany.

(Figure 1.20). Video printers and video cassette recorders used in the early days of video arthroscopy have been replaced with digital capture devices. Video and still images are captured directly off the camera during procedures. These captured images are transferred to a computer for editing, stored on disks or thumb drives, used for computer presentations, or printed for distribution to clients and referring veterinarians. The highest quality still images are obtained with digital capture systems. Capture of video during procedures is an optional method of documentation, but short video clips are recommended as opposed to recording whole procedures as this requires extensive editing to provide an acceptable product. Most capture devices can be set to a predetermined video recording time.

­References Andrews, JR. & Timmerman, LA. (eds) (1997) Diagnostic and Operative Arthroscopy. WB Saunders, Philadelphia.

Arciero, RA. & Little, JS. et al. (1986) Irrigating solutions used in arthroscopy and their effects on articular cartilage. Orthopedics 9, 1511–5.

  ­Reference

Arias, JI. & Torres, C. et al. (2009) Synovial hemangioma in a dog. Vet. Surg. 38, 463–6. Austin, B. & Montgomery, RD. et al. (2007) Evaluation of three approaches to meniscal release. Vet. Comp. Orthop. Traumatol. 20, 92–7. Bardet, JF. (1998) Diagnosis of shoulder instability in dogs and cats: a retrospective study. J. Am. Anim. Hosp. Assoc. 34, 42–54. Beale, BS. & Cole, G. (2012) Minimally invasive osteosynthesis technique for articular fractures. Vet. Clin. North Am. Small Anim. Pract. 42, 1051–68. Bergenhuyzen, AL. & Vermote, KA. et al. (2010) Longterm follow-up after arthroscopic tenotomy for partial rupture of the biceps brachii tendon. Vet. Comp. Orthop. Traumatol. 23, 51–5. Bert, JM. & Posalaky, Z. et al. (1990) Effect of various irrigating fluids on the ultrastructure of articular cartilage. Arthroscopy. 6, 104–11. Bertrand, SG. & Lewis, DD. et al. (1997) Arthroscopic examination and treatment of osteochondritis dissecans of the femoral condyle of six dogs. J. Am. Anim. Hosp. Assoc. 33, 451–5. Bevan, JM. & Taylor, RA. (2004) Arthroscopic release of the medial femoropatellar ligament for canine medial patellar luxation. J. Am. Anim. Hosp. Assoc. 40, 321–30. Bilmont, A. & Mathon, D. et al. (2018) Arthroscopic management of Osteochondrosis of the glenoid cavity in a dog. J. Am. Anim. Hosp. Assoc. 54, e54503. Bolia, A. & Böttcher, P. (2015) Arthroscopic assisted femoral tunnel drilling for the intra-articular anatomic cranial cruciate ligament reconstruction in dogs. Tierarztl. Prax. Ausg. K Kleintiere Heimtiere 43, 299–308. van Bree, HJ. & Van Ryssen, B. (1998) Diagnostic and surgical arthroscopy in osteochondrosis lesions. Vet. Clin. North Am. Small Anim. Pract. 28, 161–89. Bright, SR. (2010) Arthroscopic-assisted management of osteochondritis dissecans in the stifle of a cat. J. Small Anim. Pract. 51, 219–23. Bright, SR. & May, C. (2011) Arthroscopic partial patellectomy in a dog. J. Small Anim. Pract. 52, 168–71. Cole, G. & Beale, B. (2020) Minimally invasive Osteosynthesis techniques for articular fractures. Vet. Clin. North Am. Small Anim. Pract. 49, 213–30. Cook, JL. & Tomlinson, JL. et al. (2001) Arthroscopic removal and curettage of osteochondrosis lesions on the lateral and medial trochlear ridges of the talus in two dogs. J. Am. Anim. Hosp. Assoc. 2001 37, 75–80. Cook, JL. & Kenter, K. et al. (2005) Arthroscopic biceps tenodesis: technique and results in six dogs. J. Am. Anim. Hosp. Assoc. 41, 121–7.

Cusack, L. & Johnson, M. (2013) Arthroscopic assessment for patellar injuries and novel suture repair of patellar fracture in a cat. J. Am. Anim. Hosp. Assoc. 49, 267–72. Deneuche, AJ. & Viguier, E. (2002) Reduction and stabilisation of a supraglenoid tuberosity avulsion under arthroscopic guidance in a dog. J. Small Anim. Pract. 43, 308–11. Ertelt, J. & Fehr, M. (2009) Cranial cruciate ligament repair in dogs with and without meniscal lesions treated by different minimally invasive methods. Vet. Comp. Orthop. Traumatol. 22, 21–6. Fearnside, SM. & Preston, CA. (2002) Arthroscopic management of septic polyarthritis in a dog. Aust. Vet. J. 80, 681–3. Franklin, SP. & Devitt, CM. et al. (2013) Outcomes associated with treatments for medial, lateral, and multidirectional shoulder instability in dogs. Vet. Surg. 42, 361–4. Gielen, I. & van Bree, H. et al. (2002) Radiographic, computed tomographic and arthroscopic findings in 23 dogs with osteochondrosis of the tarsocrural joint. Vet. Rec. 150, 442–7. Gradinger, R. & Träger, J. (1995) Influence of various irrigation fluids on articular cartilage. Arthroscopy. 11, 263–9. Jurvelin, JS. & Jurvelin, JA. (1994) Effects of different irrigation liquids and times on articular cartilage: an experimental, biomechanical study. Arthroscopy. 10, 667–72. Kim, K. & Lee, H. et al. (2016) Feasibility of Stifle Medial Meniscal Release in Toy Breed Dogs with and without a Joint Distractor. Vet. Surg. 45, 636–41. Luther, JF. & Cook, JL. et al. (2005) Arthroscopic exploration and biopsy for diagnosis of septic arthritis and osteomyelitis of the coxofemoral joint in a dog. Vet. Comp. Orthop. Traumatol. 18, 47–51. McCarthy, TC. (1999) Arthroscopy. In: Veterinary Endosurgery. (ed Freeman, LJ.), pp. 237–250. Mosby, St Louis. McCarthy, TC. (2005) Arthroscopy. In: Veterinary Endoscopy for the Small Animal Practitioner (ed. TC McCarthy). pp. 447–556. Elsevier-Saunders, St Louis. Miller, J. & Beale, B. (2008) Tibiotarsal arthroscopy. Applications and long-term outcome in dogs. Vet. Comp. Orthop. Traumatol. 21, 159–65. Mindner, JK. & Bielecki, MJ. et al. (2016) Tibial plateau levelling osteotomy in eleven cats with cranial cruciate ligament rupture Vet. Comp. Orthop. Traumatol. 29, 528–35. Mitchell, RA. & Innes, JF. (2000) Lateral glenohumeral ligament rupture in three dogs. J. Small Anim. Pract. 41, 511–4.

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Olivieri, M. & Ciliberto, E. et al. (2007) Arthroscopic treatment of osteochondritis dissecans of the shoulder in 126 dogs. Vet. Comp. Orthop. Traumatol. 20, 65–9. Perry, K. & Fitzpatrick, N. et al. (2010) Headless selfcompressing cannulated screw fixation for treatment of radial carpal bone fracture or fissure in dogs. Vet. Comp. Orthop. Traumatol. 23, 94–101. Person, MW. (1987) Prosthetic replacement of the cranial cruciate ligament under arthroscopic guidance. A pilot project. Vet. Surg. 16, 37–43. Person, MW. (1989) Arthroscopic treatment of osteochondritis dissecans in the canine shoulder. Vet. Surg. 18, 175–89. Reagan, BF. & McInerny, VK. (1983) Irrigating solutions for arthroscopy. A metabolic study. J. Bone Joint Surg. 65, 629–31. Ridge, PA. (2006) Isolated medial meniscal tear in a Border Collie. Vet. Comp. Orthop. Traumatol. 19, 110–2. Ridge, P. (2009) Feline shoulder arthroscopy using a caudolateral portal, a cadaveric study. Vet. Comp. Orthop. Traumatol. 22, 289–93. Ridge, PA. & Cook, JL. et al. (2014) Arthroscopically assisted treatment of injury to the lateral glenohumeral ligament in dogs. Vet. Surg. 43(5):558–62. Ritzo, ME. & Ritzo, BA. et al. (2014) Incidence and type of meniscal injury and associated long-term clinical

outcomes in dogs treated surgically for cranial cruciate ligament disease. Vet. Surg. 43, 952–8. Rochat, MC. (2001) Arthroscopy. Vet. Clin. North Am. Small Anim. Pract. 31, 761–87. Sardana, V. & Burzynski, J. et al. (2019) The influence of the irrigating solution on articular cartilage in arthroscopic surgery: a systematic review. J. Orthop. 16, 158–65. Scherrer, W. & Holsworth, I. et al. (2005) Coxofemoral arthroscopy and total hip arthroplasty for management of intermediate grade fibrosarcoma in a dog. Vet. Surg. 34, 43–6. Serck, BM. & Wouters, EE. (2019) Ununited accessory caudal glenoid ossification centre and associated joint mouse as a cause of lameness in a cat. JFMS Open Rep. 5, 2055116919879255. Smith, TJ. & Baltzer, WI. et al. (2012) Primary synovial osteochondromatosis of the stifle in an English Mastiff. Vet. Comp. Orthop. Traumatol. 25, 160–6. Staiger, BA. & Beale, BS. (2005) Use of arthroscopy for debridement of the elbow joint in cats. J. Am. Vet. Med. Assoc. 226, 401–3. Winkels, P. & Werner, H. et al. (2010) Development and in situ application of an adjustable aiming device to guide extra- to intraarticular tibial tunnel drilling for the insertion of the cranial cruciate ligament in dogs. Vet. Surg. 39, 324–33.

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2 General Technique 2.1 ­Anesthesia, Patient Support, and Pain Management A surgical plane of general anesthesia is required for arthroscopy with the same considerations that would be employed for any orthopedic surgery. Beyond this basic criterion selection of preanesthetic medications, induction agents, maintenance anesthesia, and pain management are more patient driven than they are procedure driven. Anesthetic and support needs of the young dog undergoing shoulder arthroscopy for OCD are completely different than the needs of the geriatric dog undergoing multiportal elbow arthroscopy for debriding degenerative joint disease. Pain management needs also vary greatly depending on patient needs and on the specific arthroscopic procedure that is performed; however, pain medication needs are usually significantly less than those for an open arthrotomy or other open orthopedic procedure. An example of a typical patient management protocol includes preanesthetic evaluation with CBC, blood chemistry profile, thoracic radiographs, EKG, and urinalysis. Preanesthetic, induction, and maintenance protocols that are appropriate for the patient are used based on those established for individual practices. Perioperative NSAIDs are given based on standards employed by the practice. Additional opiate pain medications are indicated for sensitive patients and for more extensive arthroscopic procedures such as multiportal elbow debridement or arthroscopic stifle debridement in conjunction with surgical management of cruciate ligament injuries. Intra-articular local anesthetics are typically not used as they damage joint cartilage (Çevik and Gergin 2018; Jayaram et al. 2019; Lo and Sciore 2009) although single intra-articular injections of some diluted local anesthetics have not been proven to be detrimental (Breu and Rosenmeier 2013; Dragoo et al. 2012; Kreuz et al. 2018). Personal experience has found that

patients, although more comfortable the day of arthroscopy, have been more painful the day after surgery when local anesthetics were used. Another concern with intra-articular placement of local anesthetics is systemic toxicity (Di Salvo and Bufalari 2015). Intra-articular systemic pain medications may be beneficial in managing postarthroscopy pain (El Baz and Farahat 2019; Moeen and Ramadan  2017; Salman and Olgunkeleş  2019). Intra-articular corticosteroids have been used occasionally in severely inflamed joints, but their use is controversial (Céleste et  al.  2005; Doyle et  al.  2005; Gogia et al. 1993; Murphy et al. 2000; Todhunter et al. 1996). Supportive treatment typically includes intravenous crystalloid fluid therapy based on patient needs. Perioperative antibiotic administration is left to the discretion of the surgeon. Padded leg wraps are applied at the end of the procedure for distal joints including the elbow, carpus, stifle, and hock. The wraps are removed prior to release on the day following arthroscopy. Postoperative icing of joints undergoing extensive arthroscopy has been used when indicated.

2.2 ­Postoperative Care Most patients are kept in the hospital until the day after arthroscopy was performed although many can be released on the day of surgery. Medications starting after the procedure include oral NSAIDs with Tramadol or other appropriate opiates. Patients are released with these medications for 7–14 days. Activity is restricted for a minimum of 2 weeks. In-house activity is limited to walking with no running, jumping, roughhousing, going up or downstairs, jumping up or down off the furniture, or jumping in or out of the car. Outside activity is limited to leash walking sufficient for urination and defecation. A recheck examination is performed at two weeks after arthroscopy, and the activity level is adjusted based on the procedure that was performed and on

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

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patient progress. Additional pain medication is prescribed as indicated.

2.3 ­Patient Preparation, Positioning, and Operating Room Setup Patients are most commonly prepared and draped in a manner similar to what would be employed for an open arthrotomy of the joint being examined. The limb or limbs are clipped, scrubbed, and draped for aseptic surgery as would be done for any open orthopedic procedure. Effective arthroscopy requires that the joint be freely movable and draping must allow a full range of flexion, extension, and rotation of the joint of interest. Endoscopes and accessory instrumentation are sterilized with cold sterilization, ethylene oxide, or by autoclaving. Many instruments that previously required cold or gas sterilization are now autoclavable greatly increasing efficiency of case management. It is very important that the specific instrument manufacturer’s recommendations for sterilization are followed. The leg is positioned and stabilized by an assistant or it can be immobilized in a holding device. The authors experience has been using an assistant. Various immobilizing and distraction devices have been designed and tested (Böttcher et  al.  2009; Devesa et  al.  2014,  2015; Gemmill and Farrell  2009; Götzens et  al.  2019; Kim et  al.  2016,  2017,  2019; Park et  al.  2018; Rovesti et al. 2015, 2018; Schulz et al. 2004; Winkels et al. 2016). Their use is at the surgeon’s preference. Basic principles of endoscopic operating room setup are followed (Freeman 1999). The patient and video monitor or monitors are arranged so that the telescope is pointed as close to directly toward the monitor as possible. This concept is essential to effective arthroscopy. Arthroscopy techniques are difficult enough to learn and master without the added disorientation of improper monitor placement. Portals are placed to achieve triangulation optimizing function for arthroscopic surgery with the telescope visual field and operative instruments positioned to converge on the intra-articular operative site in the same visual plane as seen by the surgeon (Figure  2.1). The angle between the telescope and the operative instrument is kept between 30 and 60°. Too narrow an angle increases interference of the telescope with instrumentation or what is termed sword fighting. Working at an angle of more than 90° distorts translation of hand movements to movement on the video monitor.

Figure 2.1  Triangulation in the stifle joint with the telescope (on the right) and the operative instrument (on the left) converging in the area of interest in the intercondylar notch for an operative procedure. Source: Freeman (1999). © 1999, Elsevier.

Patient positioning and operating room setup are specific for each joint, for specific procedures within each joint, and for unilateral vs bilateral procedures. Having two monitors in the operating room greatly facilitates setup and performing arthroscopy especially when multiple joints are examined, or multiple procedures are done in a single joint.

2.3.1  Shoulder Joint Bilateral shoulder arthroscopy is more commonly performed than unilateral procedures as most of the common shoulder abnormalities requiring arthroscopy occur bilaterally. When bilateral arthroscopy is being performed under the same anesthesia, the patient is positioned in dorsal recumbency with both legs suspended (Figure 2.2a) and clipping is done to allow sterile preparation to the midscapula (Figure 2.2b). Draping is done so that the patient can be rolled to each side providing access to both joints. Bilateral shoulder OCD and bilateral UCGOC procedures are performed with the patient placed in dorsal recumbency with a monitor placed at the caudal end of the patient (Figure  2.3). When the legs have been draped, the patient is rolled

2.3  ­Patient Preparation, Positioning, and Operating Room Setu

(a)

(b)

Figure 2.2  A patient positioned in dorsal recumbency with the front legs hung in preparation for bilateral shoulder and/or elbow arthroscopy. (a) An AP view and (b) a lateral view. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 2.3  Operating room setup for bilateral shoulder arthroscopy for OCD or UCGOC with the patient in dorsal recumbency. The surgeon and assistant stand on what will be the ventral side of the patient after it is rotated on the side away from the shoulder to be operated. The monitor is placed at the caudal end of the patient. This arrangement is also used for bilateral elbow arthroscopy for UAP. Source: Drawing by Cindy Cox.

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toward the side to be operated first and the surgeon stands ventral to the patient with an assistant standing on the same side caudal to the surgeon, between the surgeon and the monitor. After the first side has been completed, both surgeon and assistant move to the other side of the patient and the patient is rolled to expose the second shoulder. For bilateral bicipital tendon surgery and procedures involving medial joint structures, patient positioning and transfer from side to side is the same as for OCD and UCGOC surgery but the monitor is placed at the head of the patient and the assistant stands cranial to the surgeon, again between the surgeon and the monitor (Figure 2.4). Bilateral procedures involving manipulations in both the cranial and caudal joint compartments require two monitors: one placed at the head of the patient and one placed and the foot of the patient (Figure 2.5). Unilateral procedures in either the cranial or caudal areas of the joint are performed with the patient positioned in lateral recumbency with the joint to be examined on the upside and with the surgeon and assistant standing on the ventral side of the patient (Figure  2.6). Unilateral procedures performed with the patient in lateral recumbency can

be performed with monitor position as for bilateral procedures or with the monitor on the dorsal side of the patient directly across from the surgeon. For the craniomedial telescope portal, the patient is prepared and draped in dorsal recumbency, but the legs are left attached to the suspension system. This is an uncommonly employed technique. An easier procedure is to use an Endocameleon Arthro or a 70° arthroscope to evaluate the lateral joint structures from the lateral portals.

2.3.2  Elbow Joint Elbow arthroscopy is typically performed bilaterally at the same anesthesia, and dorsal recumbency is employed to allow access to both elbows using the same preparation as for the shoulder joint (Figure  2.2). The patient is prepared with both legs suspended, and draping is done so that the legs are freely movable and can be abducted for access to the medial aspect of both joints. Bilateral procedures for medial coronoid process pathology, for medial condylar ridge OCD lesions, and for general exploration of the elbow joints using the medial

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Figure 2.4  Operating room setup for bilateral shoulder arthroscopy for bicipital tendon transection and for other cranial or medial joint procedures with the patient in dorsal recumbency. The surgeon and assistant stand on what will be the ventral side of the patient after it is rotated on the side away from the shoulder to be operated. The monitor is placed at the cranial end of the patient. This arrangement is also used for bilateral elbow arthroscopy for medial coronoid process disease and OCD of the elbow joint. Source: Drawing by Cindy Cox.

2.3  ­Patient Preparation, Positioning, and Operating Room Setu

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Figure 2.5  Operating room setup for bilateral elbow arthroscopy with monitors at both the head and foot of the table. This operating room configuration can also be used for bilateral shoulder arthroscopy. Source: Drawing by Cindy Cox.

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Figure 2.6  Operating room setup for unilateral shoulder arthroscopy with the surgeon and assistant standing on the ventral side of the patient and the monitor placed on the dorsal side of the patient. Source: Drawing by Cindy Cox.

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(a)

(b)

Figure 2.7  (a) The front leg of a dog viewed in a caudal to cranial direction that has been draped and positioned for elbow joint arthroscopy. The leg is abducted over a one-pound cotton roll that is being used as a bolster, and the antebrachium is rotated internally. (b) A medial to lateral view of the front leg of a dog that has been draped and positioned for elbow joint arthroscopy. The leg is abducted over a one-pound cotton roll that is being used as a bolster, and the antebrachium is rotated internally. These two movements open the medial aspect of the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

telescope portal and craniomedial operative portal are performed with the patient in dorsal recumbency with the monitor placed at the head of the patient (Figure 2.4). The patient is held in dorsal recumbency with positioning supports, sandbags, or a “V” trough, the leg to be operated is abducted, and the surgeon stands on the same side as the joint being operated. The assistant stands beside the surgeon on the patient’s cranial side between the surgeon and the monitor. A bolster is placed under the elbow joint to create a fulcrum for valgus stress with internal rotation to open the medial side of the joint. A one-pound roll of cotton covered with a waterproof sterile drape is commonly used for the bolster (Figure 2.7a and b. When the first joint arthroscopy has been completed, both surgeon and assistant move to the other side of the patient and the other leg is abducted for the second procedure. Arthroscopy for bilateral ununited anconeal process removal is also performed with the patient in dorsal recumbency but with the monitor at the caudal end of the table, and the legs are abducted to provide access to the medial aspect of the joint for placement of a standard medial telescope portal, caudomedial operative portal, and a craniomedial operative portal (Figure  2.4). Ununited anconeal processes are commonly associated with medial coronoid process pathology, and this positioning with this portal selection allows evaluation of the medial coronoid process at the same time as anconeal process fragment removal. This positioning requires two monitors, one at each end of the patient (Figure 2.5). With only one monitor, there is

the problem of working away from the monitor for coronoid process revision or fragment removal if required. If a second monitor is not available, alternatives are to perform a unilateral procedure with the patient in dorsal or lateral recumbency with the monitor placed across from the surgeon on the opposite side of the patient. Then to perform the second side, the monitor is moved when the surgeon and assistant change sides. An additional alternative is to use caudal portals for access to the anconeal process with the patient in dorsal recumbency and the monitor at the head of the table. Multiportal elbow arthroscopy for debridement of degenerative joint disease is typically performed as a unilateral procedure with the patient in dorsal recumbency so that the patient can be rolled from side to side for access to both medial and lateral aspects of the joint and with the monitor at the head of the patient.

2.3.3  Radiocarpal Joint Portals for radiocarpal joint arthroscopy are all on the dorsal aspect of the joint, and procedures are typically unilateral. Dorsal recumbency with the leg pulled caudally or lateral recumbency with the limb rotated outward is employed for unilateral arthroscopy. For the occasional bilateral procedure, the patient is placed in dorsal recumbency with the monitor placed at the head of the table (Figure 2.4) and the assistant stands cranial to the surgeon. For lateral recumbency, the monitor is placed across the table from the surgeon (Figure 2.6).

2.3  ­Patient Preparation, Positioning, and Operating Room Setu

2.3.4  Hip Joint Lateral recumbency is used for arthroscopy of the hip joint, and procedures are performed unilaterally (Figure 2.8). The most common indication for hip joint arthroscopy is in young dogs with hip dysplasia prior to performing pelvic osteotomy surgery so the patient is positioned, prepared, and draped for that surgery. The monitor is placed at the head of the table or obliquely on either side of the patient and far enough cranially to be out of the way for the surgical procedure. The surgeon stands at the caudal end of the patient. The assistant stands ventral to the patient in a position to apply traction to the leg and countertraction to the ventral midline.

2.3.5  Stifle Joint The most common diagnosis with stifle arthroscopy is an injury to the cranial cruciate ligament. Unless there is another definitive diagnosis prior to arthroscopy, the patient is placed in position with draping for the corrective surgical procedure that will be performed after the

cruciate ligament injury diagnosis is confirmed. Both dorsal recumbency with the leg extended caudally (Figure 2.9) and lateral recumbency with the leg to be examined uppermost and rotated outward (Figure 2.10) can be used for diagnostic stifle arthroscopy. Dorsal recumbency with the leg extended caudally provides easier manipulation of the joint and more complete access for operative procedures. When the patient is placed in dorsal recumbency, the monitor is placed at the head of the table or obliquely on the side of the leg being examined far enough cranially to allow appropriate telescope orientation and to be out of the way of the sterile operative field for the surgical procedure. The surgeon stands at the foot of the table, and the assistant stands lateral to the patient on the same side as the joint that is being operated. For stifle arthroscopy in the lateral position, the monitor is placed dorsal to the patient, the surgeon stands ventral to the patient, and the assistant stands at the foot of the table. Dorsal recumbency is employed for bilateral arthroscopy of the stifles with the monitor at the head of the table, the surgeon at the foot of the table, and the assistant moving to be on the lateral side of the joint being operated.

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Figure 2.8  Operating room setup for hip arthroscopy with the patient in lateral recumbency and prepared for pelvic osteotomy surgery following arthroscopy. The monitor is placed at the head of the patient or obliquely on the dorsal side of the patient cranially out of the way of the aseptic field. The surgeon stands at the foot of the table or on the dorsal side at the level of the pelvis. The assistant stands on the ventral side of the patient at the level of the hind legs. Source: Drawing by Cindy Cox.

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Figure 2.9  Operating room setup for unilateral or bilateral stifle arthroscopy with the patient in dorsal recumbency, the leg extended caudally, and prepared for probable corrective cranial cruciate ligament surgery after arthroscopy has been completed. The monitor is placed at the head of the patient or on either side of the patient cranially out of the way of the aseptic field. The surgeon stands at the foot of the table, and the assistant stands on the side of the joint being operated at the level of the stifle. This operating room setup is also used for tibiotarsal joint arthroscopy. Source: Drawing by Cindy Cox.

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Figure 2.10  Operating room setup for unilateral stifle arthroscopy with the patient in lateral recumbency, the leg to be operated on the up side and externally rotated, and the monitor on the dorsal side of the patient. The surgeon stands on the ventral side of the patient and the assistant stands at the caudal end of the patient. Source: Drawing by Cindy Cox.

2.4  ­Portal Placement-Genera

2.3.6  Tibiotarsal Joint Portals for tibiotarsal joint arthroscopy can be all four quadrants of the joint: dorsomedial, dorsolateral, plantaromedial, and plantarolateral. Medial and lateral operative portals have also been used for removal of OCD fragments from the medial and lateral ridges of the talus. Dorsal recumbency with the hind legs extended caudally, and abducted is used for bilateral or unilateral procedures and provides the most flexibility for joint manipulation and access to the greatest number of portals (Figure 2.9). OCD lesions on the plantar portion of the medial ridge of the talus, the most common condition found with arthroscopy of the tibiotarsal joint, are approached using a plantaromedial telescope portal and a medial operative portal with the patient in dorsal recumbency and the hind legs abducted and extended. Ventral recumbency allows simultaneous placement of plantaromedial and plantarolateral portals but access to the dorsal portals is limited. Lateral recumbency with the limb to be operated on the upper side can be used for unilateral tibiotarsal arthroscopy with internal or external rotation of the limb for reasonable access to all four portals but this position does not have any advantages over dorsal recumbency. The monitor is placed at the head of the table for either dorsal or ventral recumbent positions or can be placed obliquely on either side of the patient far enough cranially to be out of the way of the sterile field. The surgeon stands at the foot of the table with the assistant standing on the side of the joint being operated. Dorsal recumbency is the most commonly used position because in addition to giving the most flexibility for access to all quadrants of the joint, it facilitates conversion to an open procedure should that become necessary. A bolster is placed under the tibiotarsal joint to create a fulcrum for valgus stress with internal rotation to open the medial side of the joint. The one-pound roll of cotton used for the elbow joint is too large for the tibiotarsal joint. Any sterilizable firm cylinder is usable or the one-pound cotton roll can be partially unrolled and removed prior to covering with a waterproof sterile drape.

used by various surgeons in the field are far greater than their differences. Some of these differences are in the description for locating the portal site as opposed to the actual location of the portal. Telescope portals are more definitively established and more consistent than egress and operative portals. Use of an egress portal, the sequence of portal insertion, and egress portal sites are more variable than for the telescope portal and operative portals. Most variations are not significant, are based on surgeon personal preference, and all work. Portal sites and their landmarks are discussed with each joint. For initial portal placement, the joint is palpated and landmarks for portal location are identified. A 20-gauge 1″ to 1.5″ hypodermic needle connected to a new, clean, dry 3 cc syringe is inserted into the joint at the site selected for telescope portal placement. Synovial fluid is withdrawn to ensure intra-articular placement of the needle (Figure 2.11). Joint fluid is saved for analysis and culture but is only submitted if indicated after arthroscopic examination of the joint has been completed. The joint is distended with sterile crystalloid solution using a 12 cc syringe (Figure 2.12). Fluid infusion is continued until there is sufficient pressure in the joint to push the plunger of a new plastic syringe back when finger pressure is released. Joint distension rarely requires more than 12 cc. A small stab incision is made in the skin, subcutaneous tissues, fascia, and joint capsule with a

2.4 ­Portal Placement-General Portals sites are well established for diagnostic arthroscopy and for operative procedures in the six joints currently being examined and treated with arthroscopy in small animal practice. There is not complete agreement over the exact location of some portals or in the sequence of portal placement, although similarities of the portals

Figure 2.11  The first step in portal placement is arthrocentesis. A 20-gauge 1” or 1.5” needle is inserted into the joint, and synovial fluid is withdrawn to confirm intra-articular needle placement. A sample of fluid is saved for analysis and culture if they are indicated after arthroscopy has been completed. Source: Freeman (1999). © 1999, Elsevier.

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Figure 2.12  Saline, Ringer’s solution, or lactated Ringer’s solution is injected to distend the joint. Source: Freeman (1999). © 1999, Elsevier.

no. 11 blade at the site of needle insertion. A no. 11 blade is used to allow incision into the joint and to create a skin incision large enough to allow easy escape of any fluid that leaks from the joint during the procedure. Providing easy egress through subcutaneous tissue and skin minimizes periarticular and subcutaneous fluid accumulation. The telescope cannula is inserted into the joint through the incision using the blunt obturator (Figure  2.13). The blunt obturator is preferred over a sharp trocar to decrease the risk of damage to intraarticular structures. Using a blunt obturator also allows palpation of the joint space with the obturator to assist in locating the joint. To do this, the blunt obturator is walked back and forth across the joint space “feeling” the bone on both sides of the joint and the indentation of the joint. This is especially helpful when entering the shoulder and elbow joints. When the cannula is properly positioned in the joint, the blunt obturator is removed (Figure 2.13), the arthroscope is inserted, and the telescope is locked into position in the cannula (Figure  2.14). If manipulation for positioning of the arthroscope is required after placement of the cannula within the joint prior to examination, the blunt obturator is used for positioning and to prevent articular cartilage or telescope damage. A continuous flow of irrigation solution is initiated to provide a clear visual field and to maintain joint distension during examination. The hypodermic needle at the site used for initial joint distension or a hypodermic needle placed at another location is used for temporary

Figure 2.13  After an incision is made with a no. 11 scalpel blade, the telescope cannula is inserted into the joint using a blunt obturator. When the cannula is properly positioned, the blunt obturator is removed. Source: Modified from Freeman (1999). © 1999, Elsevier.

egress (Figure  2.14) until an operative portal is established to allow egress or when indicated an egress cannula has been placed. The primary purposes of fluid flow through the joint are to maintain a clear visual field and to provide a visual space by distension of the joint. While distension of the joint capsule is necessary to visualize the joint surfaces, dogs are especially susceptible to fluid extravasation into periarticular and subcutaneous tissues. Fluid accumulation into periarticular tissues compresses the joint capsule interfering with joint examination and operative procedures. Pressures greater than 50 cm water are thought to increase extravasation of fluid in dogs. A high flow, low pressure system with just enough pressure to distend the joint facilitates visualization without increasing the risk of periarticular fluid accumulation. A high flow, low pressure system can be achieved most easily with a large multiport egress cannula or a relatively large operative portal that will allow fluid outflow. Increased input pressure will distend the joint and improve fluid flow, but without easy egress, a clear field will not be maintained and there will be an increased risk of periarticular fluid accumulation. Higher intra-articular pressure does have the advantage of compressing synovial blood vessels to decrease

2.4  ­Portal Placement-Genera

Figure 2.14  The telescope is inserted into the cannula and is locked in place. A 20-gauge 1" or 1.5" needle is placed for temporary egress at the intended operative portal site. Source: Modified from Freeman (1999). © 1999, Elsevier.

intra-articular bleeding. Higher intra-articular pressure also changes the appearance of blood vessels within the joint by compressing the blood vessels and decreasing blood flow (Video 2.1). Inflow pressure and egress flow are balanced to maintain adequate joint distension with a clear field. Inflow pressure can be adjusted by changing the elevation of the fluid bag above the patient for the gravity system, increasing or decreasing cuff pressure for the pressure-assisted system, or by adjusting the controls on an automatic mechanical arthroscopy pump. Periarticular or subcutaneous fluid entrapment can also be decreased or minimized by creating tapered portals with the skin and subcutaneous tissue incision larger than the joint capsule opening. This allows any fluid that leaks out of the joint to escape from the skin portal without being trapped in the periarticular or subcutaneous tissues. Wise port placement and configuration, adequate egress, minimal joint movement, and avoiding excessive fluid distension pressures will all help minimize fluid extravasation. With increased operator proficiency, fluid extravasation becomes less and less of an issue. When adequate fluid flow has been established to provide a clear visual field and adequate joint distension, an initial examination of the joint is performed.

Examination of the joint is first used for orientation with identification of prominent structures until the operator has an accurate understanding of telescope position within the joint. Exploration then provides an overview of joint pathology for planning surgical procedures and placement of additional portals for insertion of operative instruments. The principle of triangulation is employed for additional port placement so that the telescope does not interfere with the operative procedure being performed (Figure  2.1). Triangulation is a term used to describe positioning instruments inside a joint to optimize function. The concept is visualized with the telescope as one side of a triangle, the operative instrument as the second side, the intra-articular lesion at the apex of the triangle, and the skin as the base of the triangle. Selection of the angle of convergence of the two sides of the triangle is critical to facilitating operative arthroscopy. Too narrow or too wide, a triangle increases the difficulty of instrument manipulation and orientation and increases interference of the telescope with the operative instruments. The other critical factor in forming the optimal triangle is that the tip of the operative instrument and the optical field of the telescope must meet at the desired point within the joint. In addition to the point of intersection of the telescope and operative instrument, their angle of convergence and the anatomy of the joint must be considered, when selecting portal placement to avoid interference from the surrounding bony structures. The joint is palpated, and landmarks for operative portal placement are identified. To confirm the correct location for operative port placement, a 20-gauge 1″ to 1.5″ hypodermic needle is placed into the joint at the intended portal site (Videos 2.2 and  2.3). The intraarticular operative site and the instrument insertion point inside the joint are visualized. The needle is repositioned until the optimal point of insertion with the correct angle of placement is achieved. A small stab incision is made at the portal site with a no. 11 blade, and the operative portal is created with blunt dissection using a curved mosquito hemostat. Or if preferred an operative cannula is placed into the joint. For many operative procedures, it is easier to insert instruments directly into the joint through the tissue tract without using a cannula. When the procedure has been completed, the joint is flushed to remove debris. The telescope is moved around the joint to look for debris, and fluid flow from the telescope cannula is used to wash debris out of the joint. Egress is facilitated at this time by placing a cannula at the operative portal site and moving the cannula into the area of debris to enhance debris egress. A palpation

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probe is also be used to dislodge debris fragments or they can be grasped with forceps and removed. With completion of this important step, the instruments, tel-

escope, and cannulas are removed. Skin sutures are placed at each portal site.

­References Böttcher, P. & Winkels, P. et al. (2009) A novel pin distraction device for arthroscopic assessment of the medial meniscus in dogs. Vet. Surg. 38, 595–600. Breu, A. & Rosenmeier, K. (2013) The cytotoxicity of bupivacaine, ropivacaine, and mepivacaine on human chondrocytes and cartilage. Anesth. Analg. 117, 514–22. Céleste, C. & Ionescu, M. et al. (2005) Repeated intraarticular injections of triamcinolone acetonide alter cartilage matrix metabolism measured by biomarkers in synovial fluid. J. Orthop. Res. 23, 602–10. Çevik, O. & Gergin, ÖÖ (2018) [The chondrotoxic and apoptotic effects of levobupivacaine and bupivacaine on the rabbit knee joint]. Rev. Bras. Anestesiol. 68, 605–12. Devesa, V. & Rovesti, GL. et al. (2014) Evaluation of a joint distractor to facilitate arthroscopy of the hip joint in dogs. J. Small Anim. Pract. 55, 603–8. Devesa, V. & Rovesti, GL. et al. (2015) Evaluation of traction stirrup distraction technique to increase the joint space of the shoulder joint in the dog: a cadaveric study. Res. Vet. Sci. 100: 283–90. Di Salvo, A. & Bufalari, A. (2015) Intra-articular administration of lidocaine in anaesthetized dogs: pharmacokinetic profile and safety on cardiovascular and nervous systems. J. Vet. Pharmacol. Ther. 38, 350–6. Doyle, AJ. & Stewart, AA. et al., (2005) Effects of sodium hyaluronate and methylprednisolone acetate on proteoglycan synthesis in equine articular cartilage explants. Am. J. Vet. Res. 66,48–53. Dragoo JL and Braun HJ, et al. The in vitro chondrotoxicity of single-dose local anesthetics. Am. J. Sports Med. 2012; 40(4):794–799. El Baz, MM. & Farahat, TEM. (2019) Efficacy of adding Dexmedetomidine to intra-articular Levobupivacaine on postoperative pain after knee arthroscopy. Anesth Essays Res. 13, 254–8. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Gemmill, TJ. & Farrell, M. (2009) Evaluation of a joint distractor to facilitate arthroscopy of the canine stifle. Vet. Surg. 38, 588–94. Gogia, PP & Brown M. et al. (1993) Hydrocortisone and exercise effects on articular cartilage in rats. Arch. Phys. Med. Rehabil. 74, 463–7.

Götzens, B. & Medl, SC. et al. (2019) Ex vivo cadaveric study of a laterally placed Leipzig stifle distractor for arthroscopic evaluation of the lateral meniscus in dogs. Vet. Surg. 48(S1), O25–33. Jayaram P & Kennedy DJ et al.(2019) Chondrotoxic effects of local anesthetics on human knee articular cartilage: a systematic review. PM R 11, 379–400. Kim, K. & Lee, H. et al. (2016) Feasibility of Stifle Medial Meniscal Release in Toy Breed Dogs with and without a Joint Distractor. Vet. Surg. 45, 636–41. Kim, JH. & Heo, SY. et al. (2017) Arthroscopic detection of medial meniscal injury with the use of a joint distractor in small-breed dogs. J. Vet. Sci. 18, 515–20. Kim, J. & Jeong, J. et al. (2019) Evaluation of a selfretaining distractor for hip joint arthroscopy in toy breed dogs. BMC Vet. Res. 15, 35. Kreuz, PC. & Steinwachs, M., et al. (2018) Single-dose local anesthetics exhibit a type-, dose-, and timedependent chondrotoxic effect on chondrocytes and cartilage: a systematic review of the current literature. Knee Surg. Sports Traumatol. Arthrosc. 26, 819–30 Lo, IK. & Sciore, P. (2009) Local anesthetics induce chondrocyte death in bovine articular cartilage disks in a dose- and duration-dependent manner. Arthroscopy 25, 707–15. Moeen SM & Ramadan IK (2017) Dexamethasone and Dexmedetomidine as an adjuvant to intraarticular bupivacaine for postoperative pain relief in knee arthroscopic surgery: a randomized trial. Pain Physician 20, 671–80. Murphy, DJ & Todhunter, RJ. et al., (2000) The effects of methylprednisolone on normal and monocyteconditioned medium-treated articular cartilage from dogs and horses. Vet. Surg. 29, 546–57. Park, JY. & Jeong, BS. et al. (2018) Evaluation of an arthroscopic stifle lever for stifle joint distraction in toy breed dogs. J. Vet. Sci. 19, 693–8. Rovesti, GL. & Devesa-Garcia, V. et al. (2015) Evaluation of a distractor to increase joint space of the stifle joint in dogs: a cadaveric study. Vet. Comp. Orthop. Traumatol. 28, 179–85. Rovesti, GL. & Devesa, V. et al. (2018) Facilitation of arthroscopic visualization and treatment of meniscal tears using a stifle joint distractor in the dog. BMC Vet. Res. 14, 212.

  ­Reference

Salman, N. & Olgunkeleş, B. (2019) [Effects of intraarticular tramadol, magnesium and ketamine on postoperative pain in arthroscopic meniscectomy]. Rev. Bras. Anestesiol. 69, 35–41. Schulz, KS. & Holsworth, IG. et al. (2004) Self-retaining braces for canine arthroscopy. Vet. Surg. 33, 77–82.

Todhunter, RJ & Fubini, SL. et al. (1996) Effect of methylprednisolone acetate on proteoglycan and collagen metabolism of articular cartilage explants. J. Rheumatol. 23, 1207–13. Winkels, P. & Pozzi, A. et al. (2016) Prospective evaluation of the Leipzig stifle distractor. Vet. Surg. 45, 631–5.

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3 Shoulder Joint Arthroscopy of the shoulder joint is indicated when there is front leg lameness with shoulder pain, crepitus, instability; or radiographic changes suggestive of OCD, ununited caudal glenoid ossification center, ununited supraglenoid tubercle, mineralization of the bicipital or supraspinatus tendons, intra‐articular fractures, or degenerative joint disease. Many of these conditions occur bilaterally, and arthroscopy of the contralateral joint is generally recommended. The time required to look in a normal shoulder joint with arthroscopy is minimal, typically less than five minutes, carries minimal risk of complications or increased morbidity plus it eliminates the possibility of having to perform a second procedure with the additional anesthetic episode and expense. In small animal practice, shoulder arthroscopy is commonly employed in the dog, first being reported in 1986 (Person  1986) but has also been performed in the cat (Bardet 1998). The pattern of shoulder pain may localize the disease process and reorder an index of suspicion for a specific shoulder disease but typically shoulder pain cannot be localized sufficiently to make a definitive diagnosis. Hyperextension pain is the classic finding with shoulder OCD but can also occur with ununited caudal glenoid ossification center, bicipital tendon injuries, and soft tissue injuries of the caudal, medial, and lateral structures of the shoulder. Pain on full flexion of the shoulder joint has been found to be as effective in diagnosing OCD as hyperextension and produce a pain response with many of the other conditions. Pain on palpation of the craniomedial aspect of the joint over the bicipital grove, on hyperflexion of the shoulder, while the elbow is extended, or on forced internal rotation of the shoulder are suggestive of bicipital tendon injury. Instability of the shoulder is also an indication for shoulder arthroscopy and is inconsistently detected as cranial–caudal drawer instability, medial–lateral drawer instability, or abduction instability. There is considerable variation in the degree of instability that

can be defined with soft tissue injuries of the shoulder joint, the normal shoulder is not totally stable in these manipulations, and there can be bilateral involvement making comparative evaluation very difficult. Absence of detectable instability does not rule out soft tissue injury to the support structures of the shoulder joint. Radiographic changes defining shoulder pathology such as OCD, ununited caudal glenoid ossification center, ununited supraglenoid tubercle, supraspinatus or bicipital tendon mineralization, and intra‐articular fractures provide a diagnosis and confirm indication for arthroscopy. Most soft tissue injuries of the shoulder do not show radiographic changes. Increased joint fluid seen with CT, MRI, or ultrasound is sufficient information to warrant arthroscopy even if there are no other findings with these imaging techniques. A significant increase in joint fluid volume obtained by arthrocentesis is helpful in confirming joint involvement and providing additional incentive for performing arthroscopy. Many conditions involving the shoulder joint are subtle and difficult to define even with all the above techniques, and exploratory arthroscopy may be required to establish a diagnosis or to rule the shoulder out as a source of the lameness.

3.1 ­Patient Preparation, Positioning, and Operating Room Setup For unilateral shoulder arthroscopy, the patient is placed in lateral recumbency with the shoulder to be examined on the upside, the monitor is placed dorsal to the patient, and the leg is suspended for preparation and draping (Figure  2.6). The surgeon and assistant stand ventral to the patient with the assistant either to the right or left of the surgeon depending on the area of most interest in the joint.

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

3.2  ­Portal Sites and Portal Placemen

To perform bilateral shoulder arthroscopy (Figures 2.3–2.5), the patient is placed in dorsal recumbency with both legs suspended for preparation and draping. Preparation and draping are done to allow the patient to be rolled from one side to the other during the procedure (Figures  2.2a,b,  3.1, and  3.2). Monitors are placed at the head and foot of the patient when procedures are planned in both cranial and caudal joint compartments and if two monitors are available (Figure 2.5). If only one monitor is available, the monitor is placed at the foot of the table for procedures performed in the caudal portion of the joint such as OCD or UCGOC (Figure 2.3) or at the head of the table for bicipital tendon evaluation and transection, and for procedures involving the medial aspect of the joint (Figure 2.4). The

assistant and surgeon stand together on the side of the table away from the joint to be examined. The patient is rolled toward the surgeon to expose the first shoulder for arthroscopy (Figure  3.2). When the first shoulder procedure has been completed, the surgeon and assistant move to the other side of the table and the patient is rolled to expose the second shoulder. Bilateral procedures can be easily performed at the same time in this manner, asepsis is easily maintained, and bilateral shoulder arthroscopy is well tolerated by patients. Since OCD and UCGOC are commonly bilateral conditions, this technique is frequently employed.

3.2 ­Portal Sites and Portal Placement 3.2.1  Telescope Portals A lateral portal is the most commonly employed telescope portal for shoulder arthroscopy and provides access for procedures in the caudal, cranial, and medial areas of the joint (Figures  3.3 and  3.4). This portal is

Figure 3.1  Preparation for bilateral shoulder arthroscopy with the legs draped to allow access to the lateral aspect of both shoulder joints when the patient is rolled from side to side. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.2  Patient was positioned for shoulder arthroscopy by being rolled toward the surgeon and assistant. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.3  Arthroscopy portals on the lateral aspect of the shoulder joint. The three portals shown are the lateral (asterisk), the caudolateral (square), and the craniolateral (triangle) portals. The lateral portal site is the most common telescope portal site and is located distal to the tip of the acromion process through to the acromion body of the deltoid muscle. The caudolateral portal site is used as an operative portal for OCD and UCGOC surgery. The craniolateral portal is used as the operative portal for bicipital tendon transection, medial soft tissue injury modification, and as a telescope portal for access to the synovial sheath of the bicipital tendon. Both operative portal sites are also used as egress portals when indicated. Source: Modified from Freeman (1999). © John Wiley & Sons.

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Figure 3.4  Alignment of the lateral telescope portal seen on an anterior–posterior view of the shoulder joint. Source: Modified from Freeman (1999). © John Wiley & Sons.

placed distal to the tip of the acromion process and through the acromion portion of the deltoideus muscle. The exact distance of this portal from the tip of the acromion process varies depending on patient size and conformation. Evaluation of preoperative shoulder radiographs is very helpful in establishing the correct portal site. This portal can also be placed at the cranial margin of the acromion portion of the deltoideus muscle at an indentation that is palpable where the joint capsule is covered with only subcutaneous tissue and skin. In thin dogs, the lateral margin of the articulation of the scapula with the humerus can be palpated at this site as the joint is moved. Craniolateral or craniomedial telescope portals are used occasionally for assessment of the lateral labrum of the glenoid, for access to the medial joint space, and for access to the bicipital groove (Figure 3.5). These portals are rarely placed as the initial telescope portal and are most commonly established after examination of the joint from the lateral portal if it is determined that one of these portals is needed. This portal is placed medial (craniomedial portal) or lateral (craniolateral portal) to the origin of the bicipital tendon into the cranial compartment of the joint. This telescope portal when placed lateral to the bicipital tendon also allows access to the bicipital extension of the joint capsule. Locating the site for this portal is established using the same procedure employed for locating operative portal site placement by inserting a 20‐gauge hypodermic needle into the joint under arthroscopic guidance (Figure 3.6). Two techniques have been used to establish these portals as a telescope portal site. When the desired location has been determined, an operative cannula is

Figure 3.5  Cranial shoulder portals shown on an anterior– posterior view of the joint. Craniolateral and craniomedial telescope portals (asterisks) lateral and medial to the bicipital tendon and an operative portal over the distal extension of the synovial sheath of the bicipital tendon (square). Source: Modified from Freeman (1999). © John Wiley & Sons.

Figure 3.6  A 20-gauge hypodermic needle placed in the craniolateral portal site as seen with a telescope looking cranially from the lateral portal. Dorsal is up and cranial is to the left. The supraglenoid tubercle is seen in the upper right with the bicipital grove at the bottom and the bicipital tendon is visible crossing the picture from top to bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

inserted using visual guidance with the arthroscope, an exchange rod or switching stick is placed into the operative cannula, the operative cannula is removed, the telescope and cannula are removed from the original lateral portal, the telescope cannula is inserted at the new site over the switching stick, the switching stick is removed, and the telescope is reinserted into its cannula. Another method of establishing this portal is to

3.2  ­Portal Sites and Portal Placemen

visually position the tip of the telescope into the craniolateral or craniomedial portal site from inside the joint, the telescope is removed from the cannula leaving the cannula in the joint with the tip of the cannula held at the new portal site, the sharp trocar is inserted into the cannula and locked in place, the cannula is pushed through the joint capsule and overlying tissues until it exits from the skin, the trocar is removed, a switching stick is inserted into the tip of the cannula, the cannula is removed from the original portal site, the cannula is slid over the switching stick into the new portal site, the switching stick is removed, and the telescope is replaced.

3.2.2  Operative Portals A caudolateral portal is the most common operative portal in the shoulder joint. This portal is used for removing OCD cartilage flaps, for debriding OCD cartilage defects, for removing caudal cul‐de‐sac joint mice, and for removal of UCGOC lesions (Figures  3.3 and 3.7). This portal is placed caudal and distal to the lateral telescope portal with distance depending on patient size. This is in the same location as the caudolateral surgical approach to the humoral head for open removal of OCD lesions. It is very helpful to determine the distance from the telescope portal site to the opera-

Figure 3.7  Arthroscopy portals are used for access to lesions in the caudal portion of the shoulder joint. The telescope is in the lateral portal and is directed caudally to allow visualization of humoral head OCD lesions, UCGOC lesions and for examination of the caudal cul-de-sac and caudal joint capsule. An instrument is present in the caudolateral operative portal providing triangulation with the telescope visual field. An egress needle is present at the cranial portal site. Source: Modified from Freeman (1999). © 1999, Elsevier.

tive portal site on radiographs before surgery. Stating distances in centimeters, as is done in many publications, is of little help because of the variation in patient size. To locate this portal site, the OCD lesion is visualized with the telescope and a 1.5″ 20‐gauge hypodermic needle or a 2.5″ 20‐gauge spinal needle is directed into the joint to intersect the axis of the telescope view at the caudal margin of the shoulder joint. Correct needle placement is confirmed by intra‐articular visualization of the needle with the telescope (Figure 3.8). The needle is repositioned until it enters the joint at the correct location and is at an angle allowing access to the OCD lesion (Videos 2.1 and 3.1). If the needle angle is oblique to the joint space, access to the OCD lesion may not be possible. A short incision is made at the needle site with a no. 11 blade through skin, subcutaneous tissues, and superficial muscle fascia. A curved mosquito hemostat with the curved tip pointed cranially is used to bluntly dissect through the muscle and into the joint (Figure  3.9). The hemostat jaws are spread to create a large enough tissue tract for removal of OCD cartilage fragments. Operative cannula placement at this site is done with a stab incision made at the needle site with a no. 11 blade, and the needle is replaced with the operative cannula. This is one of the more difficult portals to place due to muscle thickness over the joint, the angle at which the joint is approached, and lac of close bony landmarks.

Figure 3.8  A 20-gauge hypodermic needle at the caudolateral portal site as seen with the telescope looking caudomedially from the lateral portal. The location of the needle and its angle are correct for portal placement. Dorsal is up and cranial is to the right. The humeral head fills the bottom of the image, the caudal margin of the glenoid articular surface is seen at the top of the image, and the lateral margin of the OCD lesion is seen in the center with the needle touching its caudolateral margin. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.9  A curved mosquito hemostat in the shoulder joint at the caudolateral operative portal site as seen with the telescope looking caudomedially from the lateral portal. Dorsal is up and cranial is to the right. The tip of the hemostat is seen penetrating the caudolateral joint capsule, the caudal margin of the glenoid is at the top, the humeral head is at the bottom, and the medial joint capsule is seen in the background extending across the middle of the image. There is significant villus synovial reaction in the joint capsule typical with OCD of the shoulder joint. The caudal portion of the OCD cartilage defect is visible in the lower right of the image without the free cartilage flap. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

A craniolateral operative portal site is employed for transecting the bicipital tendon, for medial ligament and joint capsule procedures, and for removal of arthroliths in the cranial area of the joint (Figures  3.3, 3.5, and  3.10). This portal is placed medial to the greater tubercle of the humerus and lateral to the bicipital tendon. The site for this portal is determined by palpation of the greater tubercle and the bicipital groove. A 1.5″ 20‐gauge hypodermic needle is inserted at the selected site, and correct needle placement is viewed from inside the joint with the arthroscope (Figure 3.6). A skin incision is made with a no. 11 blade, and an operative cannula is placed or a tissue tract is dissected with a mosquito hemostat. Joint entry is visualized with the arthroscope from inside the joint to ensure accurate placement and prevent joint damage.

3.2.3  Egress Portals Placement of an egress portal for shoulder joint procedures is optional, and egress is typically allowed through the operative portals. When an egress portal is needed for operative procedures in the caudal portion of the joint, it is placed at the same site as the craniolateral operative portal and is inserted using the same technique. Operative procedures in the cranial portion of

Figure 3.10  Arthroscopy to access lesions in the cranial portion of the shoulder joint uses the lateral telescope portal with the telescope directed cranially to allow visualization of the bicipital tendon, bicipital groove, medial ligaments, and cranial area of the joint. Source: Modified from Freeman (1999). © John Wiley & Sons.

the joint use the caudolateral operative portal site as an egress portal if one is needed.

3.3 ­Nerves of Concern with Shoulder Joint Arthroscopy Nerve injury is a concern in placement of the portals for shoulder arthroscopy. Damage to nerves is the most serious complication of arthroscopy in human medicine. Nerves that are at risk when performing shoulder joint arthroscopy include the suprascapular nerve when placing the lateral telescope portal and the axillary nerve when placing the caudolateral operative portal. The suprascapular nerve courses around the cranial aspect of the scapula, across the lateral aspect of the scapular neck distal to the end of the scapular spine and lies dorsal to the margin of the glenoid (Figure 3.3). A common mistake made by beginners in small animal shoulder arthroscopy is to miss the joint when inserting the telescope cannula and slide dorsally along the lateral aspect of the scapular neck. When this happens, the suprascapular nerve is at risk. The axillary nerve is at risk when placing the caudolateral operative portal of the shoulder joint. The axillary nerve runs with the axillary artery across the caudal aspect of the shoulder joint from dorsomedial to distal and lateral around the joint capsule (Figure  3.3). This

3.4  ­Examination Protocol and Normal Arthroscopic Anatom

places the nerve in close proximity to the caudolateral operative portal site used for removal of OCD lesions of the humoral head and removal of ununited caudal glenoid ossification center fragments. This nerve can be damaged when there is difficulty establishing this operative portal. To place this portal safely, a skin incision is made with sharp extension through the subcutaneous tissue and superficial muscle fascia then a curved mosquito hemostat is used for blunt dissection beyond this level into the joint. The use of blunt dissection in the area of the nerve minimizes the chances of nerve damage. There are no nerves at risk with placement of the craniolateral operative portal of the shoulder joint.

3.4 ­Examination Protocol and Normal Arthroscopic Anatomy When first entering the shoulder joint through the lateral telescope portal, anatomic structures are identified that allow orientation within the joint. The concave glenoid articular surface and the convex humeral head articular surface (Figure 3.11), the cranial arm of the origin of the medial glenohumeral ligament (Figure 3.12), the less distinct caudal arm of the origin of the medial glenohumeral ligament (Figure 3.13), the subscapularis tendon (Figure 3.14), the medial joint space with the joint capsule (Figure 3.15), and the origin of the bicipital tendon (Figure 3.16) are all important and easily identifiable

Figure 3.11  Anatomic structures in the shoulder joint used for orientation from the lateral telescope portal include the concave glenoid articular surface at the top and the convex humeral head articular surface filling the bottom of the image. Dorsal is up and cranial is to the right. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.12  The cranial arm of the medial glenohumeral ligament is another anatomic structure in the shoulder joint used for orientation with the telescope looking medially from the lateral portal. Dorsal is up and cranial is to the right. The cranial arm of the medial glenohumeral ligament is seen as an oblique band of bright white tissue extending across the center of the picture with subtle linear strands. The humeral head fills the bottom of the image, the medial margin of the glenoid articular surface is seen at the very top above the glenohumeral ligament, and the supraspinatus tendon is in the center background below the glenohumeral ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.13  The less distinct caudal arm of the medial glenohumeral ligament is also an identifiable anatomic structure that can be used for orientation with the telescope looking medially from the lateral portal. Dorsal is up and cranial is to the right. The medial margin of the glenoid articular surface is at the top of the image with the medial humeral head at the bottom and the caudal arm of the glenohumeral ligament seen as a raised band of tissue crossing he medial joint from caudodorsal to cranioventral. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.14  The subscapularis tendon seen as an oblique band of linear strands cranial and deep to the cranial arm of the glenohumeral ligament on the medial aspect of the shoulder joint is an additional structure that can be used for orientation. The medial margin of the glenoid articular surface is at the very top, the cranial arm of the glenohumeral ligament is running in a craniodorsal to caudoventral direction at right angles to the subscapularis tendon below the glenoid, and the humeral head articular surface is visible across the bottom of the image. Dorsal is up and cranial is to the left. The telescope is looking medially from a lateral portal and the joint is abducted to open the medial joint space to allow observation of these structures. There is mild villus synovial reaction seen in this joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

structures to use for orientation. A common mistake in starting shoulder arthroscopy is to be too deep with the tip of the telescope against the medial joint structures. Backing the telescope laterally until an image is visible will correct this problem. Once orientation is achieved, the joint is examined in a systematic manner to ensure that all important structures of the joint are seen. By directing the tip of the telescope cranially and angling the 30° view of the telescope medially, the bicipital tendon is visualized originating on the supraglenoid tubercle of the scapula (Figure 3.16). The bicipital tendon is evaluated as it traverses into the bicipital groove (Figure 3.17) and as far distally as possible (Figure 3.18). A mesotendon is present on the cranial margin of the bicipital tendon attaching the bicipital tendon to the joint capsule of the bicipital groove (Figure  3.19). The medial end of the transverse humeral ligament is identified medial to the origin of the bicipital tendon (Figure  3.20) and as it traverses across the bicipital groove cranial to the bicipital tendon (Figure 3.21). The telescope is swept medially and caudally to visualize the craniomedial joint space between the bicipital tendon

Figure 3.15  Caudal to the subscapularis tendon and medial glenohumeral ligament orientation is established using the glenoid articular surface seen at the top of the image, the humeral head articular surface at the bottom, and the medial joint capsule seen as the slightly vascular tissue in the background running horizontally across the center. Dorsal is up and cranial is to the left. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.16  Orientation is also done using the bicipital tendon. The tendon is the thick structure running obliquely across the center of this image with its origin on the supraglenoid tubercle seen in the upper right to where it disappears cranial to the bicipital groove of the humerus in the lower left. The enlargement seen at the lateral aspect of the tendon, the right side in the image, immediately adjacent to the bone is the normal typical appearance of its origin. Visible vascularity at the tendon origin is also normal. The image is obliqued putting dorsal to the upper right, lateral to the lower right, and the telescope is looking cranially from the lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 3.17  By advancing the telescope further into the joint from its position in the previous figure the bicipital tendon is seen entering and curving into the bicipital groove. The 30 degree telescope angle is looking distally with cranial up on the image with dorsal or proximal to the left and lateral is to the right. The tendon is the tubular structure running from the bottom left across to the right and away from the telescope. A small portion of bicipital groove cartilage is seen at the bottom and cranial joint capsule extends across the top of the image. The vascular pattern seen in the joint capsule and on the cranial surface of the tendon is normal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

and the cranial margin of the subscapularis tendon (Figure 3.22). As the telescope view is moved caudally, the articular surfaces of the scapula and humeral head are examined making sure to visualize both articular cartilage surfaces (Figures  3.11 and  3.15). Particular attention is given to articular cartilage on the caudal portion of the humeral head under the glenoid (Figure 3.23) and caudal to the glenoid (Figure  3.24), where OCD lesions are typically found. The telescope must be between the joint surfaces to see the area of interest on the humeral head (Figure  3.23). Inadequate telescope depth with the tip of the telescope lateral to the glenoid (Figure 3.25) may miss OCD lesions. The central area of the glenoid (Figure 3.11) is examined with the telescope rotated so the 30° angle is directed cranially, caudally, and dorsally. The caudal margin of the glenoid is visualized from the lateral aspect (Figure  3.25), from the caudal aspect (Figure  3.26), and from the ventral direction (Figure 3.27). Caudal movement of the telescope is continued to evaluate the caudal cul‐de‐sac of the joint (Figure 3.28). Medial structures of the joint used for orientation are examined carefully including the medial margin of the glenoid with the medial joint capsule (Figure  3.15), medial soft tissue structures of the

Figure 3.18  Further examination of the bicipital tendon is possible in some patients from the lateral telescope portal but switching to the craniolateral portal may be required to achieve this view. The telescope is looking distally down the bicipital tendon with cranial up on the image, lateral is to the right, and medial is to the left. The tendon is seen as the tubular structure traversing distally in the bicipital groove with joint capsule arching across the top and the bicipital groove curved across the bottom of the image. The irregular white ridge of tissue on the left is the lateral labrum of glenoid and is normal. The tuft of tissue protruding from the cranial aspect of the tendon immediately distal to the labrum is fat that is normally present at the origin of the tendon. The vascular pattern seen in the joint capsule is typical for a normal joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.19  The mesotendon of the bicipital tendon is seen in this image as a pink band of tissue on the cranial surface, left side, of the tendon. Cranial is to the left, dorsal or proximal is to the upper right, distal is to the lower left, and the telescope is looking craniomedially from a craniolateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.20  The medial origin of the transverse humeral ligament is seen as a band of tissue in the center of the image running horizontally from the medial ridge of the proximal bicipital grove in the lower left for a short distance to disappear behind the medial margin of the bicipital tendon. The telescope is looking craniomedially from a lateral portal with craniolateral to the right, dorsal is up, and craniomedial is to the left. The origin of the bicipital tendon is on the right with the bicipital groove at the bottom, medial joint capsule to the left, and a small portion of the supraglenoid tubercle is seen at the top of the image. The irregular mildly vascular tissue at the proximal end of the bicipital tendon is normal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.21  The transverse humeral ligament is seen in some patients as it traverses the bicipital groove cranial to the bicipital tendon. Cranial is up and to the right on this image with lateral to the lower right and the telescope is looking distally from a craniolateral portal. The bicipital tendon is visible traversing the picture from lower left to the right with the transverse humeral ligament seen as an indistinct white band of tissue circling the cranial aspect of the bicipital extension of the joint capsule. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.22  The craniomedial joint capsule is seen as a space medial to the bicipital tendon, cranial to the tendon of the subscapularis muscle, ventral to the cranial arm of the glenohumeral ligament, and craniodorsal to the articular surface of the humeral head. Cranial is to the right, dorsal is up, and the telescope is looking craniomedially from a lateral portal. The bicipital tendon is seen on the right with a small portion of the supraglenoid tubercle at the upper right, the ventral margin of the cranial arm of the medial glenohumeral ligament is coursing across the top of the image, the subscapularis tendon is seen running obliquely on the left side of the image, and the medial humeral head is visible in the lower left of the picture. There is minor villus synovial reaction along the upper portion of the cranial margin of the subscapularis tendon and the remainder of the structures are normal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

joint  with particular attention being directed at the glenohumeral ligament (Figures  3.12–3.14), the subscapularis tendon (Figure  3.14), and the craniomedial joint space (Figure 3.22) by redirecting the tip of the telescope from caudally to cranially. Examination of medial structures of the joint is facilitated by abducting the leg to open the medial aspect of the joint (Figures 3.14 and 3.29). The lateral labrum of the glenoid is visualized by retracting the telescope as far as possible without exiting the joint, angling the scope cranially, and rotating the angle of view of the telescope dorsally and laterally (Figure 3.30). Rotation of the telescope to position the viewing angle laterally allows visualization of the lateral collateral ligament of the shoulder joint (Figure  3.31). Considerable variation exists in the appearance of the origin of the bicipital tendon with some showing a well‐defined vascular pattern (Figure 3.16), or no visible vasculature (Figure 3.32), and some with an accumulation of adipose tissue attached to the origin of the tendon (Figure 3.33). Routine examination of the joint can be completed in most patients with the joint in a neutral position but,

3.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 3.23  The caudal smooth articular surface of the humeral head under the caudomedial portion of the glenoid articular surface where OCD lesions are commonly seen. Cranial is to the right and dorsal is up on the image with the telescope positioned in the joint space between the bones and looking caudomedially from a lateral portal. The humeral head fills the lower right, the glenoid articular surface is at the top, and the caudomedial joint capsule is in the background across the center of the image. The medial margin of the glenoid is seen in the upper right extending across the picture to become the caudal margin at the far left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.24  The humeral head surface caudal to the glenoid in the area where OCD lesions are also commonly seen. The caudomedial joint capsule is filling the upper half of the picture with the humeral head filling the bottom half. The vascular supply in the joint capsule is normal. Dorsal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.25  The caudal portion of the glenoid in the upper left, the humeral head in the lower left, and the caudal joint capsule in the upper right seen with the tip of the telescope lateral to the glenoid. Dorsal is up and cranial is to the left. The telescope is looking caudomedial from a lateral portal. Viewing in this position may miss OCD lesions and the telescope is inserted further into the joint so that its tip is between the joint surfaces to ensure that an adequate area of the humeral head is examined. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.26  Normal caudal humeral head articular surface and caudal margin of the glenoid seen from the caudal aspect. Cranial is to the left and dorsal is up with the telescope looking caudomedially from a lateral portal and with the 30 degree angle directed cranially. The caudal margin of the glenoid is in the upper left with the humeral head filling the lower left of the image and the caudal joint capsule to the upper right. The subtle band of soft tissue irregularity following the curve of the glenoid margin is normal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.27  The caudal margin of the glenoid seen from the ventral aspect with the 30- degree of the telescope directed dorsally. Dorsal is up and cranial is to the left with the telescope pointed caudomedially from the lateral portal. The glenoid is in the upper left, a small portion of the caudal humeral head is seen to the lower left the caudal joint capsule is filling remainder of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.28  Normal caudal cul-de-sac of the shoulder joint with the caudal margin of the humeral head articular surface at the far right, attachment of the joint capsule to the humerus in the lower right, and the distended caudal joint capsule filling the left side of the image. Cranial is to the right and dorsal is up with the telescope looking caudodistally from the lateral portal and with the 30 degree angle directed medially. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

in some cases, flexion, extension, abduction, and rotation of the joint may be required to access and assess all areas of the joint. For a complete assessment of the lateral joint capsule, lateral collateral ligament, and lateral labrum of

Figure 3.29  Normal medial glenohumeral ligament demonstrating the classic “Y” anatomy with the joint abducted to improve visualization. The normal medial margin of the glenoid articular surface is seen across the top and the normal humeral head articular surface is seen at the bottom of the picture. Cranial is to the left and dorsal is up with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.30  The cranial portion of the lateral cartilaginous labrum of the glenoid visualized by retracting the telescope, directing the tip cranially and rotating the viewing angle dorsally. The telescope is looking cranially, lateral is to the right, and dorsal is up. The lateral labrum is the rounded wide band of white tissue in the upper right of the image with the supraglenoid tubercle in the upper left, the humeral head articular surface at the bottom and the origin of the bicipital tendon in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the glenoid a cranial or craniomedial telescope portal may be required. In large breed dogs, the 4.0 mm Endocameleon facilitates examination of the lateral joint

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.31  The lateral collateral ligament of the shoulder joint is visualized by retraction of the telescope, directing the tip cranially, and rotating the viewing angle laterally. The lateral collateral ligament is the prominent raised band of tissue filling the right side of the image, the bicipital tendon is seen on the right in the background cranial to the lateral collateral ligament, and humeral head articular surface is to the lower left. Lateral is to the right, and dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.33  An accumulation of adipose tissue at the origin of the bicipital tendon is a common normal finding. Cranial is to the left and dorsal is up with the telescope looking craniomedially from a lateral portal. The tip of the supraglenoid tubercle is filling the upper right with humeral head articular cartilage across the bottom and the origin of the bicipital tendon filling the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5 ­Diseases of the Shoulder Diagnosed and Managed with Arthroscopy 3.5.1  Osteochondritis Dissecans (OCD)

Figure 3.32  A normal origin of the bicipital tendon demonstrating a typical cuff of synovial tissue around its origin with no visible vascular pattern. Cranial is to the left and dorsal is up with the telescope looking craniomedially from a lateral portal. A small portion of the supraglenoid tubercle is at the top, humoral articular surface extends across the bottom, craniomedial joint capsule is to the right, and the proximal bicipital tendon is filling the left center of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

structures and the medial joint compartment with the lens angle adjusted to greater than 60°. Arthroscopes are also available with fixed angles greater than 30° that can be used for examining these areas of the joint.

This is the most common indication, diagnosis, and operative procedure performed with arthroscopy in the shoulder joint (Bilmont et  al.  2018; Olivieri et al. 2007; Person 1989). The classic presentation of a front leg lameness in a young large breed dog with pain on hyperextension or hyperflexion of the shoulder joint is sufficient indication for arthroscopy. Although primarily seen in large breed dogs, OCD has been reported and arthroscopy performed in small breed dogs (Bruggeman et  al.  2010). Radiographs are taken to confirm a diagnosis prior to arthroscopy, but normal radiographs do not rule out OCD or eliminate the indication for arthroscopic exploration of the joint. Although radiographs have been the standard for diagnosing OCD contrast arthrography, CT, MRI, and ultrasound have also been used (Wall et al. 2014; Van Bree et  al.  1993; Vandevelde et  al.  2006). Bilateral shoulder arthroscopy is routinely recommended even with unilateral presentation of OCD because OCD is most commonly a bilateral disease that may only show unilateral signs. It is far easier for the patient and more

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economical for the client to perform a bilateral procedure rather than two unilateral procedures. Arthroscopy for OCD is performed with a lateral telescope portal and a caudolateral operative portal. Egress through the operative portal site is employed, but a craniolateral egress portal is placed if needed. This is seldom necessary. OCD lesions are typically easily visible on the caudal surface of the humoral head as a loose flap of cartilage with easily defined free margins (Figure 3.34). There are many variations of OCD lesion appearance from thick fragments containing bone (Figure  3.35) to thin cartilage flaps (Figure  3.36) and from small (Figure  3.37) to large (Figure  3.38). Thin lesions can be large (Figure 3.36) or small (Figure 3.37) and thick lesions can also be large (Figures  3.35 and  3.38) or small (Figure  3.39). The free cartilage of OCD lesions is most commonly a single smooth flap of loose cartilage (Figures  3.34–3.36, and  3.38) but also appear as irregular soft cartilage (Figure 3.40), irregular partially fragmented cartilage flaps (Figure 3.41), frayed or crushed cartilage (Figure 3.42), small frayed lesions (Figure 3.43), and fraying on the margins of OCD cartilage flaps (Figure 3.37). The wide variety of OCD lesion appearance extends to normal cartilage surface that is

only found by palpation indicating a soft or movable area of cartilage (Figure 3.44), blister‐like areas of cartilage with intact cartilage margins that are large (Figure 3.45) or small (Figure 3.46), indentation of otherwise normal‐appearing cartilage (Figure  3.47), smooth (Figure  3.48) or irregular cartilage that is not raised or displaced (Figure  3.49), raised lesions with clearly visible nondisplaced margins that have a smooth (Figure  3.50) or irregular (Figure  3.51) surface, and raised margins with an intact cartilage surface at the margin (Figure  3.52). Chondromalacia (Table  3.1) appearing as small loose (Figure  3.53), small attached

Figure 3.35  A thick OCD lesion containing bone is seen on the caudal portion of the humeral head. Dorsal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.34  A classic OCD lesion on the caudal portion of the humeral head with an easily seen loose cartilage flap having a free margin. Cranial is to the left and dorsal is up in this picture. Synovial villi from the caudal joint capsule are visible on the right side of the image. Localized villus synovial reaction is common directly over the OCD lesion. The telescope is looking caudomedially from a lateral portal. Unless stated otherwise all the following images of OCD lesions showing the loose cartilage in the defect on the caudal humeral head are taken with this telescope orientation from the lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.36  A thin humeral head OCD lesion on the caudal portion of the humeral head. Caudal is to the right and dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.37  An atypically small humeral head OCD lesion. The frayed margin of the cartilage in this lesion is not common. Dorsal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.38  An atypically large humeral head OCD lesion seen filling the upper half of the figure. Dorsal is up and caudal to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure 3.54), or large (Figure 3.55) areas of fibrillated cartilage are a visible indication of an OCD lesion. All grades of chondromalacia are also seen in humeral head cartilage surrounding OCD lesions and on the glenoid articular surface. The majority of OCD lesions with typical free cartilage flaps have the complete disk of loose cartilage still in the cartilage defect with no missing cartilage (Figures 3.34–3.38). Lesions are also seen with a small portion (Figure  3.56), most (Figure  3.57), or all (Figure 3.58) of the loose cartilage missing from the site

Figure 3.39  A small thick humeral head OCD lesion. Grade I chondromalacia is present in the humeral head cartilage surrounding the lesion. Caudal is to the right with dorsal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.40  A small soft OCD lesion is seen with an irregular surface and a ragged margin. Grade I chondromalacia is present in the glenoid articular cartilage medial to the humeral head OCD lesion seen as an indentation. The glenoid is visible across the top of the image with medial joint capsule visible in the background and humeral head with the OCD lesion filling the bottom of the picture. Dorsal is up and caudal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

of the OCD lesion. When a partially or completely empty cartilage defect is found, it means that part or all of the cartilage flap has broken‐free and has been displaced into another area of the joint. It is necessary to find these loose cartilage fragments and remove them from the joint. They are found in the caudal cul‐de‐sac as small recent fragments (Figure  3.59) or as large

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Figure 3.41  A humeral head OCD lesion that appears to be starting to fragment with fracture lines extending cranially from its caudal margin seen as a cleft on the near or lateral side and as a fold on the far or medial side. Fraying is also seen on at the caudomedial corner of the cartilage flap. A small portion of the glenoid is seen in the upper left of the lesion and synovial villi are seen in the upper right. Caudal is to the right and dorsal is up.

Figure 3.42  A frayed or crushed OCD cartilage flap indicating chronic trauma to the lesion. The tip of a 20 gauge needle is seen in the upper right of the lesion placed to establish the location for an operative portal. The caudomedial glenoid is seen across the top of the image with a caudal margin osteophyte along its caudal margin. Caudal is to the right and dorsal is up in this picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

remodeled fragments (Figure 3.60), in the medial joint space ventrally (Figure  3.61) or medial to the glenohumeral ligament (Figure  3.62), in the craniomedial joint space (Figure 3.63), and in the bicipital extension of the joint capsule. Remodeled cartilage fragments, originating from OCD lesions, are also found free

Figure 3.43  A very small OCD lesion that is mostly frayed with little free intact cartilage. Dorsal is up and caudal is to the left. There are ghost villi seen as white avascular projections in the upper right of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.44  An unusual OCD lesion in the humeral head with no visible cartilage abnormality and no visible margins on initial examination. A 2.0 mm palpation probe inserted through a caudolateral portal is being used to identify an area of soft cartilage or Grade I chondromalacia. Dorsal is up and cranial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

floating in the joint space as small (Figure  3.64) and large arthroliths (Figure 3.65) and small or large arthroliths lodged between the glenoid and humeral articular surfaces (Figures  3.66 and  3.67). Free cartilage pieces can be any size from submacroscopic chips that are free floating (Figure 3.68) or are imbedded in the synovium (Figure  3.69) to large osteocartilaginous arthroliths (Figures 3.60 and 3.67).

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.45  A large blister like OCD lesion on the humeral head with loose cartilage but unbroken lesion margins. In any other location this could be called Grade I chondromalacia but because it is on the caudal humeral head where OCD lesions are found penetration to subchondral bone is suspected. Manipulation with a probe confirmed that this was a full thickness loose flap of cartilage. Dorsal is up and caudal is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.46  A small blister like OCD lesion on the humeral head with loose cartilage and without fracture of the cartilage margins giving the appearance of Grade I chondromalacia. The loose cartilage in this patient was much larger than what is indicated by the size of the blister. Dorsal is to the upper right and caudal is to the left. The tip of a curved mosquito hemostat that has been passed through a caudolateral portal is visible in the upper left of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

The bed or cartilage defect of OCD lesions is variable in appearance due to duration of the lesion prior to examination and due to other unknown factors. The underlying bone of acute lesions can have either a viable pink smooth (Figure 3.70) or roughened (Figure 3.71) surface and can also have a smooth speckled brown and

Figure 3.47  An OCD lesion seen as an indentation in otherwise normal appearing cartilage. In any other location this could be called Grade I chondromalacia, but manipulation revealed a full thickness loose cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.48  An area of smooth cartilage representing an OCD lesion that is not raised or displaced and has an indistinct margin seen as an irregular ridge of tissue running horizontally across the humeral head. The central portion of this lesion has the appearance of normal to Grade I chondromalacia with the periphery exhibiting the characteristics of Grade II chondromalacia. The telescope is looking medially from a lateral portal with dorsal up and cranial to the right. The medial portion of the glenoid is seen in the upper left with the humeral head filling the bottom, and the medial joint capsule with villus reaction is seen across the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

white avascular or necrotic appearance (Figures  3.58 and  3.72). With chronicity, the bone can become covered with a layer of material that appears to be fibrin

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Figure 3.49  An OCD lesion appearing as an irregular area of cartilage swelling that is not displaced or raised and has a poorly defined margin that could be called Grade I chondromalacia. The humeral head fills most of the image with medial joint capsule in the upper background. The telescope is looking medially from a lateral portal with dorsal up and cranial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.50  A smooth slightly raised OCD lesion with a non-displaced clearly visible margin. The humeral head fills the bottom of the image with normal cartilage to the left and the loose OCD cartilage to the right. Dorsal is up and cranial is to the left with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure  3.73) or fibrous tissue (Figure  3.74). Cartilage islands surrounded by pink viable bone (Figure 3.75) or surrounded by brown avascular bone (Figure 3.76) and cartilage covering a large area of the lesion originating from the center (Figure 3.77) or periphery (Figure 3.78). The margins of OCD lesions have a sharply defined vertical cartilage edge with vertical striations when recently formed or at the time the free cartilage flap is removed (Figure  3.70). With increasing duration, the cartilage

Figure 3.51  An irregular raised OCD lesion with a nondisplaced clearly visible margin. The humeral head fills the bottom of the image with normal cartilage to the left and the loose OCD cartilage to the right. Dorsal is up and cranial is to the left with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.52  A non-displaced OCD lesion with a raised margin where the cartilage at the margin has not ruptured. Dorsal is up and the telescope is looking medially from a lateral portal with cranial to the right. Medial joint capsule with villus reaction fills the top of the image, the humeral head is at the bottom, and the OCD lesion margin is seen as a distinct ridge of cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

edge becomes frayed (Figure 3.71), rounded with loss of the vertical striations (Figures  3.74, 3.75, 3.77), and chronic lesions can lose cartilage thickness at the margin developing a thin tapered edge (Figures  3.72 and 3.79). Degenerative joint changes typically occur with chronicity of OCD, and all grades of chondromalacia

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Table 3.1  Modified outerbridge chondromalacia grading system. Grade 0

Normal cartilage

Grade I

Blisters, softening, and swelling

Grade II

Fibrillation or fissures with partial (50%) loss of thickness (or?) involving an area greater than 1.5 cm diameter Grade IV Full‐thickness loss of cartilage with exposed bone Grade V

Full‐thickness loss of cartilage with exposed eburnated bone Figure 3.54  A small area of cartilage fibrillation, Grade II chondromalacia, without any loose cartilage representing an atypical humeral head OCD lesion is seen in the canter of the picture. Dorsal is up and cranial is to the right with the telescope looking medially from a lateral portal. The humeral head fills the bottom of the image with medial joint capsule filling the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.53  A small area of raised cartilage with fibrillation is seen in the center of the picture, Grade II chondromalacia, representing an atypical humeral head OCD lesion. The glenoid articular cartilage fills the upper portion of the picture with medial glenohumeral ligament visible extending across its medial margin, a wedge of medial joint capsule is present across the middle, and the humeral head is at the bottom. The telescope is looking medially from a lateral portal with dorsal up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

are seen (Table 3.1). Typical OCD lesions are by definition Grade IV or Grade V chondromalacia, depending on the condition of the underlying bone. Atypical OCD  lesions appear as all grades of chondromalacia and if seen at other sites would be diagnosed as chondromalacia and not OCD. This raises the question: Are all cartilage abnormalities on the caudal area of the humeral head OCD, are these lesions a form of subclinical OCD that does not form loose cartilage but allows chondromalacia to develop, or are some truly chondromalacia with a different pathophysiology? This question has not been answered.

Figure 3.55  A large loose humeral head OCD lesion cartilage fragment with fibrillation of the loose cartilage. The cartilage surface appears to be Grade III chondromalacia but is actually Grade IV chondromalacia because the lesion extends to the level of bone. Grade I chondromalacia is present in the glenoid articular cartilage opposite the humeral head lesion. Dorsal is up with cranial to the right and the telescope is looking medially from a lateral portal. The humeral head is at the bottom with the glenoid at the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Grade I chondromalacia at an OCD lesion site can appear as normal cartilage that is only found by palpation indicating a soft area of cartilage (Figure 3.44),

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Figure 3.56  A free OCD cartilage flap with a small portion of the loose cartilage missing from the cartilage defect. Dorsal is up and cranial is to the right with the telescope looking medially from a lateral portal. Medial joint capsule is visible in the upper background with the humeral head filling the bottom of the image and the free OCD cartilage extending across the middle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.57  An OCD lesion with most of the free cartilage flap missing from the cartilage defect. Dorsal is up and cranial is to the left. The telescope is looking medially from a lateral portal. The irregular tan exposed bone of the humeral head representing the OCD cartilage defect fills the lower center of the image with the cartilage rim of the defect visible in the lower left and in the background along the medial margin the defect. The cartilage in the center of the picture extending laterally from the far cartilage margin is part of the loose cartilage that is still in its original position. This cartilage was elevated and removed. Synovial villi are seen to the upper right and partially obscure the OCD lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

as  blister‐like areas of cartilage with intact cartilage margins that are large (Figure  3.45) or small (Figure 3.46), indentation of otherwise normal‐appearing cartilage (Figure 3.47), and smooth (Figure 3.48) or

Figure 3.58  An OCD lesion with all of the free cartilage flap missing from the cartilage defect. A palpation probe is visible extending from a caudolateral operative portal into the medial joint. Exposed bone of the OCD defect with a smooth surface and tan coloration fills the lower portion of the image. A rim of irregular mildly frayed cartilage margin is visible along the medial margin of the defect and a small portion of the lateral cartilage margin is seen at the bottom of the picture. Villus synovial reaction is seen across the top. The telescope is looking medially from a lateral portal with dorsal up and cranial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.59  Small loose cartilage fragments in the caudal cul-de-sac of the shoulder joint in a dog with a humeral head OCD lesion that was partially missing from the primary lesion site. The fragments are seen in the bottom of the image with the caudal margin of the humeral head articular surface on the left and caudal joint capsule to the right. Dorsal is up and cranial is to the left. The telescope is looking caudally and medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.60  A large loose remodeled cartilage fragment seen in the caudal cul-de-sac of the shoulder joint representing as a curled structure. This arthrolith represents the entire free cartilage of the OCD lesion. The telescope is looking caudomedially from a lateral portal with dorsal up and caudal to the right. A small portion of the caudomedial margin of the glenoid is visible at the very top of the picture with humeral head across the bottom. The OCD cartilage defect covered with fibrin and early cartilage regeneration is seen to the lower left with a rim of normal cartilage to the lower right of the visible humeral head. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.61  A free cartilage fragment originating from an OCD lesion displaced ventrally into the medial joint space of the shoulder joint. Grade II chondromalacia is visible on the humeral head cartilage. The telescope is looking medially from a lateral portal with dorsal up in the picture. Medial joint capsule fills the upper image with humeral head across the bottom and the free fragment behind, medial to, the humeral head. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.62  A free cartilage fragment originating from an OCD lesion is seen in the medial joint spaced displaced craniomedially and lodged between the glenohumeral ligament seen across the top of the image and the subscapularis tendon to the lower left. The humeral head is to the lower right. The loose fragment is seen as the white smooth material in the center of the image. Fragments in this location can be completely hidden behind the glenohumeral ligament. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.63  A small loose cartilage fragment originating from an OCD lesion displaced into the craniomedial joint space. The telescope is looking medially from a lateral portal with cranial to the right and dorsal up. The free cartilage fragment is seen in the center of the picture with humeral head to the lower left, medial glenohumeral ligament to the upper left, and subscapularis tendon covered with synovial reaction behind the cartilage fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.64  A large OCD cartilage flap floating free in the joint space between the glenoid and humeral head articular surfaces. This free cartilage represents the entire OCD lesion. The glenoid articular surface is at the top with humeral head at the bottom and dorsal is up. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.65  A small OCD origin arthrolith free floating in the joint space between the glenoid and humeral head articular surfaces. The OCD lesion is seen as the irregular minimally displaced cartilage in the center of the picture. The exact site of origin of this small fragment was not determined as no areas of missing cartilage were visible. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. The medial margin of the glenoid is visible to the upper left, the humeral head fills the bottom of the image, and medial joint capsule with villus reaction is seen in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

irregular cartilage that is not raised, lose, or displaced (Figure  3.49). Grade II chondromalacia can appear as attached areas of fibrillated cartilage (Figure 3.54) and as irregular attached cartilage (Figure  3.80) at OCD lesion sites. Grade III chondromalacia is also seen at OCD lesion sites with deeper cartilage damage covering a larger area (Figure  3.81). Chondromalacia Grades II and III are based on two criteria, the depth of cartilage damage and the size of the lesion (Table 3.1). When the

Figure 3.66  OCD origin arthroliths trapped in the OCD cartilage defect between the humeral head and the glenoid articular surface. The glenoid articular cartilage fills the upper image with a small area of humeral head seen at the bottom. A 20-gauge hypodermic needle is seen to the right entering the joint from the site for a caudolateral operative portal. The tip of the needle is on the caudal arthrolith and a second arthrolith is to the left of the first. Grade III chondromalacia is present in the glenoid articular cartilage above the trapped fragments and the humeral head cartilage defect covered with cartilage regrowth seen as an irregular white surface is below and in front of the arthroliths. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.67  A large arthrolith in the shoulder joint trapped between the glenoid and humeral head articular surfaces. This free fragment was partially mineralized and is in an inverted position so that the articular surface is down. The glenoid articular surface is at the top and the humeral head is at the bottom of the picture. The telescope is looking medially from a lateral portal and dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

two criteria are in conflict, it can be difficult to state the Grade with accuracy. An example of this (Figure 3.80) has mild cartilage damage that is clearly Grade II but covers an area that would make it a Grade III. In this case, if one parameter exceeds the Grade II criteria does this make the lesion Grade III? It can be argued that if either of the criteria is the higher grade then the lesion

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.68  Small free-floating cartilage chips originating from an OCD lesion seen in the caudal cul-de-sac of the shoulder joint. The telescope is looking caudomedially from a lateral portal with cranial to the left and dorsal up. A portion of the humeral head is visible to the lower left with caudal joint capsule filing the remainder of the image. The free cartilage chips are seen as white areas against the hyperemic joint capsule. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.69  An unusual finding of cartilage chips originating from an OCD lesion that are fixed to or imbedded in the synovium. The chips are seen as indistinct white areas on the joint capsule surface. The telescope is looking caudomedially into the caudal cul-de-sac of the joint with a small potion of the caudal margin of the glenoid visible to the upper left. Dorsal is up and caudal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

is that higher grade. I do not know if the answer to this question has been defined. Full‐thickness lesions, Grade IV chondromalacia, without evidence of loose cartilage at the lesion site or elsewhere in the joint are also seen at humeral head OCD lesion sites (Figure 3.82). Grade V lesions have not been seen as a primary finding but Grade V‐like lesions with large areas of exposed smooth bone are seen with displaced cartilage flaps (Figures 3.72, 3.76, and 3.79). The presence of loose cartilage confirms a diagnosis of OCD and, in these cases, chondromalacia is

Figure 3.70  A irregular pink bone surface in the cartilage defect following removal of an OCD cartilage flap. The defect fills the bottom of the image with a typical sharp well attached cartilage margin seen as a white band across the far side of the defect. Medial joint capsule with villus reaction is seen across the top of the picture. Dorsal is up and cranial is to the left with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.71  Rough pink viable bone in the cartilage defect following removal of an OCD cartilage flap seen filling the center of the image. Small red spots of blood are seen scattered over the surface of the defect. Dorsal is up and the telescope is looking medially from a lateral portal with medial joint capsule in the upper background. A rim of cartilage is seen across the bottom and extending around to the medial margin of the defect across the middle of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

secondary to the pathophysiology of OCD. The presence or absence of loose cartilage may not be able to be determined visually and manipulation with a palpation probe or other instrument may be needed to confirm a diagnosis. Chondromalacia of all grades also occurs in the shoulder joint cartilage secondary to the original OCD pathology. Mild cartilage changes representing Grade I chondromalacia are seen in humeral head cartilage around OCD lesions (Figure  3.39) and in the glenoid

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Figure 3.72  Smooth brown and white speckled avascular or necrotic bone in the OCD defect after removal of a free cartilage flap. The bone surface of the defect fills most of the picture with a curved hemostat and joint capsule seen in the upper background. Dorsal is up and caudal is to the right with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.74  A chronic OCD cartilage defect covered with fibrous appearing tissue and islands of cartilage in a lesion with a displaced OCD cartilage flap. The arthrolith representing the OCD lesion is not visible in the picture. The humeral head is to the lower left with caudal joint capsule filling the upper right of the image. Dorsal is up with caudal to the right and the telescope is looking caudomedially from a lateral portal. Cartilage at the cranial margin of the lesion is seen as an elevated ridge to the left with islands of new cartilage seen as raised white areas in the lesion at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.73  An OCD cartilage defect following removal of a free cartilage flap with a layer of fibrin appearing material covering the bone of the defect. The humeral head defect fills the lower left of the image with caudal joint capsule to the upper right. Dorsal is up with caudal to the right. The telescope is looking caudomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

articular cartilage directly opposite the OCD lesion (Figure 3.55) or peripheral to the OCD lesion (Figure 3.40). Grade II chondromalacia occurs as moderate cartilage roughening on the humeral head around OCD lesions (Figure 3.83) but can be seen in all areas of the joint as can more severe Grade III damage (Figure  3.83), full‐ thickness Grade IV cartilage degeneration (Figure 3.84), and Grade V lesions (Figure  3.85). These changes are potentially due to continued release of inflammatory chemicals into the joint or due to wear from trapped cartilage or osteocartilaginous fragments between the joint surfaces. Osteophytes are commonly seen in joints with chronic lesions on either the glenoid (Figure  3.86) or humeral head margins.

Figure 3.75  An attached island of new cartilage is seen as a raised white area in the center of the image that has formed in an OCD lesion in a shoulder joint. The displaced detached cartilage flap was found as an arthrolith and is not visible in the picture. The exposed bone of the cartilage defect appears pink and extends from the lower left to the back center of the figure. Full thickness cartilage with an irregular rounded edge surrounds the exposed bone. Small areas of blood are seen along the bone-cartilage junction. The telescope is looking medially from a lateral portal with dorsal up. The glenoid articular surface is in the upper right of the image and the humeral head with the OCD lesion is in the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.76  An attached island of new cartilage is seen forming in the center of an OCD lesion after removal of the free cartilage flap. A loose cartilage fragment is seen to the upper left of the fixed island of new cartilage. Dorsal is up and caudal is to the right with the telescope looking medially from a lateral portal and the hemostat has been inserted through a caudolateral portal. A small portion of glenoid is seen in the upper left with medial joint capsule covered with villus synovial reaction between the glenoid and humeral head at the bottom. The exposed bone of the OCD defect, seen to the lower right, surrounding the cartilage island has a speckled brown avascular necrotic appearance. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Villus synovial reactions develop secondary to OCD and become progressively more significant with chronicity and severity. A small local area of synovitis is typically present early in the disease process on the caudal joint capsule, where it overlies the primary OCD lesion (Figures 3.52, 3.58, 3.70, 3.71, and 3.82). Inflammation of the synovium and villus formation develops throughout the joint with time, and examples are seen in many of the OCD figures. One area of specific interest is the synovial tissue cuff surrounding the proximal bicipital tendon and is a common area for development of this OCD‐related villus synovial reaction (Figures  3.87 and 3.88). This finding has commonly been erroneously termed bicipital tenosynovitis. Tendon injury or tendinopathy can occur at this location, but the synovial reaction can also be a nonspecific inflammatory reaction to any joint pathology even with a normal bicipital tendon. Villus synovitis secondary to OCD can be severe involving any and all areas of synovial surface in the shoulder joint (Figures  3.89–3.91). Atypical synovial reaction on intra‐articular tendons and ligaments occurs with a pannus‐like appearance (Figure 3.92a) rather than the typical villus synovial reaction. Joint capsule fibrosis is also seen with chronic OCD lesions (Figure 3.92b).

Figure 3.77  A chronic OCD cartilage defect where a large area of the bone is covered with newly formed attached cartilage originating in the bed of the lesion. The 2.0 mm hook probe inserted through a caudolateral portal was used to confirm attachment of cartilage at the margin of the lesion and that the cartilage islands were fixed to bone. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. Joint capsule fills the upper half of the image with the humeral head at the bottom. The medial margin of the OCD defect is seen as a sharp cartilage layer behind the probe. There is a small amount of viable exposed bone to the right of the probe tip. The remainder of the OCD lesion between the probe tip and the bottom of the image is covered with newly formed cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Atypical cartilage lesions are seen on the humeral head in the area typical for OCD lesions without any visible loose cartilage or arthroliths (Figure 3.93). These findings could be due to atypical development of cartilage defects without a loose or free flap of cartilage or when the loose OCD cartilage has broken‐free and been completely resorbed. Chondromalacia in this area of the humeral head is also seen with no other indication that an asymptomatic typical OCD lesion occurred (Figure  3.94). This finding may be secondary to normal stresses to this part of the joint or due to a subclinical OCD lesion where the cartilage became thicker during growth but did not break loose to develop into clinical OCD. 3.5.1.1  OCD Lesion Removal and Management

When the lesion has been identified, a needle is inserted into the joint at the operative portal site to confirm the best location for portal placement (Figure  3.8) (Videos 2.1 and 3.1). Angle of the needle is important as it needs to be aligned with the joint space to provide instrument access to the OCD lesion. Incorrect needle angle (Figure 3.95), and thus portal placement, does not allow access to the needed area of the joint making management of the OCD lesion more difficult. Once the needle

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Figure 3.78  A large thick area of attached cartilage partially filling the cranial portion of a chronic OCD lesion in a joint where no free cartilage or arthrolith was found. It is not possible to tell from this image if this is newly formed cartilage or if this is a portion of the OCD lesion cartilage that was not loose or that reattached itself. The remainder of the defect is covered with thinner newly formed cartilage. The telescope is looking medially from a lateral portal and dorsal is up with caudal to the left. A small indistinct portion of glenoid is seen to the upper left with villus covered joint capsule filling the upper half of the image and humeral head to the lower right. Cartilage with Grade I chondromalacia forming the cranial margin of the lesion is to the lower right with the thick cartilage extending caudally from this cranial margin cartilage and the remainder of the OCD lesion extends to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

is correctly placed, a skin incision is made where the needle penetrates the skin. This incision is about one centimeter long and penetrates through the skin, subcutaneous tissue, and superficial muscle fascia but no deeper. The operative portal is established using a curved mosquito hemostat to bluntly dissect through the remaining muscle, fascia, through the joint capsule (Figure  3.9), fully into the joint (Figure  3.96), and the jaws are spread (Figure  3.97) to dilate the soft tissues establishing the operative portal. OCD lesion removal is typically performed without an operative portal cannula. The tip of the curved mosquito hemostat is used to elevate and free the cartilage flap (Figure  3.98) until it is almost completely detached (Videos 3.2 and  3.3). The attached portion of the margin of the lesion is partially broken away from the normal cartilage using the closed tip of the hemostat (Figure  3.99) or by opening the hemostat and grasping the cranial margin of the loose cartilage (Figure  3.100). A small area of attachment is left intact to stabilize the free cartilage fragment. The hemostat is repositioned across the free cartilage (Figure 3.101) to include as much of the flap as possible (Figures 3.102 and 3.103) and the hemostat is elevated,

Figure 3.79  A chronic OCD lesion with a typical thin tapered cartilage margin due to cartilage remodeling and wear. Soft tissue is seen covering the bed of the OCD cartilage defect in the lower right of the visible humeral head that could be fibrous tissue or fibrocartilage with a smooth pink appearance. A small indistinct glenoid margin is visible in the upper left with villus covered joint capsule filling the upper image and humeral head at the bottom. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.80  Grade III chondromalacia covering the majority of visible humeral head in the area where OCD lesions occur but without any free cartilage in the lesion area or elsewhere in the joint. The depth of cartilage involvement appears to be Grade II but the size makes this Grade III. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. The humeral head fills the lower left of the image with glenoid across the top and caudomedial joint capsule between the two joint surfaces in the background. Chondromalacia is also seen in the glenoid cartilage and an osteophyte ridge is present along the caudal and medial margin of the glenoid articular surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.81  Grade III chondromalacia of humeral head cartilage adjacent to a chronic OCD lesion with no identifiable free cartilage in the lesion area or elsewhere in the joint. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. The tip of a 20-gauge hypodermic needle is seen at the top of the image. The humeral head is seen at the bottom with the glenoid in the upper right and medial joint capsule with marked villus ghosts in the background. The cranial margin of the OCD cartilage defect is just visible to the very far right with chondromalacia in the center of the image covering most of the visible humeral head. Normal cartilage is present across the bottom if the picture in the foreground. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.82  Full thickness Grade IV chondromalacia of the humeral head cartilage in the area there OCD occurs without any loose or free cartilage fragments in the lesion or elsewhere in the joint. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. The humeral head to the lower right is covered with roughened cartilage and a full thickness lesion is present with exposed bone at the center of the picture. Joint capsule fills the upper right with normal joint capsule to the left and local villus synovial reaction to the right.Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.83  Chondromalacia demonstrated as mild roughening of the humeral head cartilage and moderate roughening of the glenoid cartilage in a shoulder with a chronic OCD lesion. The humeral head lesion is Grade II in cartilage damage depth and is Grade III in size. The glenoid lesion is Grade III and both depth and in size. The telescope is looking medially from a lateral portal with dorsal up and cranial is to the left. The humeral head is to the lower right and the glenoid is to the upper left with the medial glenohumeral ligament seen in the background between the two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.84  Chondromalacia of the glenoid articular cartilage with full thickness, Grade IV, degeneration in an area opposite a chronic OCD lesion in the humeral head. The telescope is looking medially from a lateral portal and the glenoid articular surface fills the image with its medial margin across the bottom of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

retracted, or rotated to break the final attachment completely freeing the cartilage (Videos 3.2–3.5). A small point of attachment is left on the cranial or craniomedial margin of the cartilage flap to hold it in place until it is removed (Figure  3.104). If the flap is completely detached, it can escape into the medial or cranial areas of

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Figure 3.85  A large Grade V chondromalacia lesion in the center of the glenoid articular surface over a chronic humeral head OCD lesion. The humeral head is at the bottom of the image with the OCD lesion seen as a crater with rough pink bone in the center of the visible humeral head. The glenoid is filling the upper picture with fibrillated cartilage seen along the lateral margin of the chondromalacia defect with a pale tan coloration to the exposed eburnated bone filling the center of the figure. The telescope is looking medially from a lateral portal with dorsal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.86  A large osteophyte is seen on the medial margin of the glenoid with Grade III chondromalacia of the glenoid articular surface in the shoulder of a dog with chronic osteoarthritis secondary to OCD. The glenoid fills the top of the image with the humeral head to the bottom right. There is a subtle line running obliquely across the center of the image representing the medial margin of the glenoid and the osteophyte is seen as the white structure deep to the glenoid. Palpation determined that this osteophyte ridge was solidly attached to the scapula. The telescope is looking medially from a lateral portal with dorsal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.87  A hyperemic cuff of villus synovial reaction around the origin of the bicipital tendon in the shoulder of a dog with OCD and a normal bicipital tendon. This is not bicipital tenosynovitis but is synovial reaction secondary to the OCD. The telescope is looking cranially from a lateral portal with dorsal to the upper right and lateral to he left. The humeral articular surface fills the lower right with the bicipital tendon in the center and villus synovial reaction around the origin of the bicipital tendon to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.88  A more extensive villus synovial reaction secondary to OCD around the origin of a normal bicipital tendon. This is not bicipital tenosynovitis but is synovial reaction secondary to the OCD. The telescope is looking craniomedially from a lateral portal with dorsal up and lateral to the right. A small portion of humeral articular cartilage is visible to the lower left with bicipital tendon indistinctly visible in the bicipital groove seen to the lower right. The proximal villus reaction appears as pale ghosts with hyperemic villi in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.89  Villus synovial reaction in the craniomedial joint space secondary to chronic OCD. The telescope is looking craniomedially from a lateral portal with cranial to the right and dorsal up. The villus reaction is seen at the center of the picture with humeral head articular cartilage across the bottom, a small portion of glenoid articular surface is at the upper right, and medial glenohumeral ligament across the top. The villus reaction in the canter of the image obscures visibility of the subscapularis tendon and there are white avascular villi at the top left partially covering the medial glenohumeral ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.90  Marked synovitis covering the medial joint capsule fills the upper figure where it is adjacent to a chronic humeral head OCD lesion. The humeral head is at the bottom with the OCD lesion covered with fresh blood involving all the exposed articular surface except for a narrow rim of cartilage cranially and medially. The telescope is looking medially from a lateral portal with dorsal up with cranial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.91  Severe synovitis on the bicipital tendon and joint capsule extending into the bicipital extension of the shoulder joint space. The telescope is looking distally from a craniolateral portal with cranial up and lateral to the right. There is a small portion of bicipital groove articular cartilage to the lower left, the bicipital tendon is seen as a linear white band of tissue running vertically in the joint to the right of the cartilage surface. Villus synovial reaction covers the joint capsule curving around image on the right side from the bottom to the top. Synovial villi obscures the origin of the bicipital tendon in the upper left and extends along the cranial margin of the tendon. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the joint and be much more difficult to grasp for removal (Figures  3.61–3.64). Fluid flow from the telescope also pushes any totally free cartilage fragments away from the field of view of the telescope further increasing the difficulty of grasping loose fragments. Turning fluid flow off momentarily may stop this movement facilitating free‐floating cartilage removal. When the cartilage flap has been completely freed and is securely grasped with the hemostat, the hemostat is retracted until the leading margin of the flap is against the joint capsule at the operative portal site. The hemostat is rotated completely, or an oscillating rotation motion is used as the hemostat is withdrawn to cause the flap to roll up around the hemostat as it slides through the tissues of the operative portal (Videos 3.2 and  3.3). Using this technique, most OCD lesions can be removed in one large piece. If the flap breaks during removal, the hemostat is reinserted to remove any remaining fragments (Figure  3.105). Portions of the free flap that are left attached to the rim of the lesion (Figures 3.57 and 3.106) are removed with hemostats or with small rongeurs. After the loose cartilage is removed, the cartilage defect is evaluated. A hook probe is inserted, and the margins of the cartilage are palpated for any loose cartilage edges (Figures 3.77 and 3.107). The curved mosquito hemostat can also be reinserted for this

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(a)

(b)

Figure 3.92  (a) An atypical pannus like synovial reaction on the glenohumeral ligament in a shoulder joint with OCD. A small area of glenoid is seen at the top with the humeral head filing the bottom and the medial glenohumeral ligament running from the upper right to the left across the center of the image. The red coloration across the surface of the tendon is a synovial reaction but has not formed villi. The telescope is looking medially from a lateral portal and dorsal is up. (b) Fibrosis of the caudal joint capsule secondary to chronic OCD. The telescope is looking caudomedially directly at the caudal joint capsule from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.93  An atypical cartilage defect in a shoulder joint with no arthroliths or loose cartilage flaps. The telescope is looking medially from a lateral portal with dorsal up. The humeral head is at the bottom with medial joint capsule filling the top of the image. The humeral head cartilage and bone defect is in a sagittal plane and is a deep narrow groove extending through cartilage and a significant distance into the bone. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

procedure (Figure 3.108) with the advantage that any loose cartilage margins can be removed without exchanging instruments. Residual loose cartilage is freed from the margin of the cartilage defect with hand instruments using straight curettes (Figure 3.109), curved curettes (Figure 3.110), or the hook probe (Figure  3.111), until there is only well‐ attached cartilage (Figure  3.70). When using the

Figure 3.94  Grade III chondromalacia in humeral head cartilage in a shoulder without any indication of OCD. Narrow hairline lines are seen in the humeral head in the area where OCD lesions are seen, and the fissure lines extend through the full thickness of cartilage to bone making these Grade III lesions. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. The humeral head fills with bottom of the image with the glenoid at the top and medial joint space between the cartilage surfaces. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

straight curette to cut loose margin cartilage, the curette is directed down against the bone cutting with downward pressure (Figure  3.112) or at an oblique angle toward the cartilage defect to cut with a sideways movement (Figure  3.113). Curved curettes are directed with the curve toward the bone to cut, with

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.95  A 20-gauge needle improperly placed at too great an angle, relative to the joint space, to allow placement of an effective operative portal for OCD lesion management. The glenoid articular surface is seen filing the upper left of the image with a small portion of humeral head at the bottom and caudal joint capsule with villus reaction to the right. The needle angle is too vertical, and an operative portal placed at this angle will not allow instrument access to the joint space at the OCD lesion site. Repositioning to align the needle with the joint space will facilitate successful completion of the surgical procedure. The telescope is looking caudomedially from a lateral portal and dorsal is up with caudal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.96  A curved mosquito hemostat fully inserted into the shoulder joint through a caudolateral portal and positioned over the top of an OCD lesion. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. The humeral head fills the bottom of the image with the caudal margin of the OCD cartilage flap seen as an elevated step extending obliquely across the humeral head. Joint capsule covered with villus reaction is seen at the top of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

traction toward the cartilage defect (Figure 3.114), or with the curve to the side also cutting with traction toward the cartilage defect (Figure 3.115) Loose cartilage fragments are removed from the floor of the defect with hand instruments (Figure 3.76). After removal of all loose cartilage from the lesion, the bed of the cartilage defect is addressed. Fixed

Figure 3.97  The hemostat jaws are opened to spread the soft tissues and establish the operative portal. The telescope is looking medially from a lateral telescope portal with dorsal up and caudal to the left. A narrow band of glenoid is seen at the top, a small portion of humeral head is seen to the lower right, medial joint capsule is in the background, and the open jaws of the hemostat fill the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.98  A curved mosquito hemostat placed through a caudolateral portal is passed under an OCD cartilage flap to free and elevated it from the underlying bone. The cartilage flap of most OCD lesions is loose, and this part of the process is easily completed. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. The OCD cartilage flap fills the center of the image with glenoid articular cartilage surface seen above and behind the OCD lesion. A small portion of humeral head is visible at the very bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

islands of attached cartilage that are a chondrocyte source for cartilage regeneration are left in place (Figures  3.75–3.78). The exposed bone of the defect is assessed further to determine whether there is viable bone (Figures 3.70 and 3.71) or whether the bone surface is avascular or necrotic bone (Figures  3.57, 3.58, and 3.72). Treatment of the bed of the defect varies with

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Figure 3.99  The attached cranial margin of the OCD cartilage flap is broken away from the normal cartilage using the closed tip of the hemostat. The caudal margin of the OCD cartilage fills the upper left of the image, the bed of the lesion is seen as tan tissue under the hemostat, and a small area of normal attached humeral head cartilage is at the bottom. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.100  The attached cranial margin of the OCD lesion can also be grasped with the hemostat to break it away from the normal cartilage. The hemostat has been inserted through a caudolateral operative portal. It is placed with the jaw opened enough to place one side above the free flap and the other below the cartilage. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. A small portion of the glenoid is seen in the upper left of the image with the humeral head to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the tissue that is present. Avascular bone is removed with hand instruments (Figure 3.116) or with the power shaver until a viable bone is identified (Figure  3.117). When the shaver is used, it is applied judiciously to remove a thin layer of bone without significantly

Figure 3.101  The jaws of the hemostat are opened and repositioned across an OCD cartilage flap. After freeing the cartilage flap except for the small point of attachment the hemostat is retracted and reinserted to grasp the free cartilage flap as far across the free cartilage as possible. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. A small portion of glenoid is visible to the upper left, the humeral head to the lower right, and the caudomedial joint capsule in the background. The free cartilage is seen in the center of the image between the jaws of the hemostat. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.102  The jaws of the hemostat are placed as far across the cartilage flap as possible and closed to grasp the loose cartilage. Dorsal is up, caudal is to the left with the free cartilage flap grasped between the jaws of the hemostat. A small portion of glenoid articular cartilage is visible to the upper right with the humeral head across the bottom of the image and the cartilage flap is in the center between the jaws of the hemostat. The telescope is looking medially from a lateral portal with dorsal up and caudal is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

deepening the defect or causing excessive bleeding (Figure 3.118). In most cases, hand instruments or shaving will produce the desired effect of exposing vascular bone with visible bleeding (Figure  3.117). When the

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.103  A free cartilage flap grasped properly with the mosquito hemostats extending the full width of the loose cartilage. Dorsal is up and caudal is to the right with the telescope looking medially from a lateral portal. The humeral head fills the bottom of the image, a small portion glenoid is visible to the upper left behind the OCD cartilage in the center of the picture. The hemostat is inserted through a caudolateral portal and is closed over the cartilage flap. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.104  The cartilage flap is pulled loose from its remaining attachment. A hemostat is inserted from a caudolateral portal across the free cartilage flap and retraction is applied to pull the last attachment away from the humeral head. The telescope is looking medially from a lateral portal. The telescope is rotated to place dorsal to the left and caudal down on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

desired vascular exposure is not achieved with hand instruments or superficial shaving, microfractures are created in the bone using a microfracture chisel (Figure  3.119). In cases with smooth viable appearing bone without visible bleeding not requiring bone removal, microfractures are also created with the microfracture chisel to improve vascular access (Figure 3.120). Microfracture chisels are available with tip angles of 0,

Figure 3.105  A loose fragment remaining after removal of an OCD lesion that broke off when the cartilage flap was pulled through the operative portal. The hemostat has been reinserted and has grasped the free-floating piece. The fragment is visible across the midlevel of the image with the caudal glenoid at the top and the humeral head at the bottom. The hemostat jaws are indistinctly seen at the right along with hyperemic joint capsule. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.106  A portion of a free cartilage flap still attached to the lesion margin that needs to be removed. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. Medial joint capsule fills the upper portion of the picture with exposed humeral head bone at the bottom and the remaining free cartilage extends from right to left across the middle level of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

30, and 70° (Figure 1.8d). The 30° or 70° tip angle microfracture chisels are used in shoulder joint OCD lesions, and the 0° model is not effective for this application. The optimum number of microfracture sites, the depth of the fractures, the microfracture pattern, and spacing has not been established and is probably case

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Figure 3.107  Probing the margin of an OCD lesion for loose cartilage using the hook probe after removal of a loose cartilage flap. The hook probe is inserted through a caudolateral operative portal with the telescope looking medially from a lateral portal. Dorsal is up and caudal is to the left. The humeral head is at the bottom of the image with the OCD defect at the lower left and normal cartilage to the lower right. In this patient the exposed cartilage margin is firmly attached to bone and no further cartilage removal is needed. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.108  Probing the margin of an OCD lesion for loose cartilage using the curved mosquito hemostat after removal of a loose cartilage flap. The hemostat is inserted through a caudolateral portal with the telescope looking medially from a lateral portal. Dorsal is up and caudal is to the right. Reactive joint capsule fills the top of the image, the humeral head is at the bottom, normal cartilage is to the lower left, and the bed of the OCD lesion is to the lower right. This patient shows firmly attached cartilage at the junction of the defect and cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.109  A loose cartilage margin is seen at the medial side of an OCD lesion seen after removal of the free flap. A dark line is seen at the junction of bone and cartilage in this image indicating that the cartilage is not attached to the bone. A 3-0 to 5-0 straight curette inserted through a caudolateral portal is being used to remove the residual loose cartilage. The telescope is looking medially from a lateral portal, dorsal is up and caudal is to the right. The exposed bone of the OCD lesion is seen at the lower right with joint capsule to the upper left and the cartilage margin of the extending obliquely across the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.110  Loose cartilage at the margin of OCD lesions can also be removed with size 3-0 to 5-0 curved curettes. In this image the curette is placed through a caudolateral portal, the telescope is looking medially from a lateral portal, dorsal is up, caudal is to the right. the glenoid is seen at the top, the humeral head OCD lesion at the bottom and joint capsule is visible in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.111  The 2.0 mm hook probe is also used to free small areas of loose cartilage along the OCD lesion margin. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. The humeral head is seen at the bottom of the image with exposed bone of the OCD lesion to the right and a tapered cartilage margin to the left. Villus covered joint capsule fills the top of the image. The probe is inserted through a caudolateral portal and a small area of loose cartilage margin seen below the tip of the probe is freed for removal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.112  Cutting loose marginal cartilage using a straight curette with the curette directed down toward the bone and cutting with downward pressure against the bone. The humeral head is at the bottom of the image with exposed bone of the OCD lesion to the lower right and loose cartilage margin to the left. The curette is inserted through a caudolateral portal, dorsal is up, caudal is to the right, and the telescope is looking medially from a lateral portal. Loose cartilage is seen under the curette and another are of loose margin is seen to the left that was removed after extraction of the piece under the curette. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.113  Cutting loose marginal cartilage using a straight curette with the curette at an angle to cut with a sideways motion. The telescope is looking medially from a lateral portal with dorsal up and caudal to the right. Exposed bone of the OCD lesion is seen in the lower left with the margin cartilage across the far edge and villus covered joint capsule filling the top of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.114  Using a curved curette to cut loose margin cartilage with the curette curve directed down and cutting done with traction toward the cartilage defect. A freed piece of cartilage is seen above and to the right of the curette tip. Dorsal is up caudal is to the right, the telescope is looking medially from a lateral portal, and the curette is inserted through a caudolateral portal. Glenoid articular surface fills the top of the image with exposed bone of the humeral head OCD lesion across the bottom seen as the smooth pink area. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

dependent. An attempt is made to penetrate and disrupt most of the area of the lesion without destroying the structural integrity of the bone. Small loose bone fragments are generated with the microfracture process (Figures  3.121 and  3.122) and are removed after the microfracture process has been completed. Defects with viable vascular bone and visible bleeding are not

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Figure 3.115  Cutting loose marginal cartilage with a curved curette with the curve at an angle to the side and cutting with traction toward the cartilage defect. Glenoid is seen at the top with humeral head at the bottom. Exposed bone of the OCD lesion is to the lower left with the cartilage margin to the right. The curette is inserted through a caudolateral portal, the telescope is looking medially from a lateral portal, dorsal is up, and caudal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.116  Removing avascular bone from the bed of an OCD lesion using a straight curette. Dorsal is up and caudal is to the left with the telescope looking medially from a lateral portal and the curette is entering the joint through a caudolateral portal. Necrotic avascular bone is seen as the smooth speckled brown area to the lower right in front of the curette that is positioned to cut into the bone with an angular rotating motion toward the telescope. Humeral head cartilage margin is on the lower left and the top of the image is filled with villus covered joint capsule. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

debrided other than to remove any loose cartilage or bone fragments (Figure 3.71). Small and atypical OCD lesions (Figures  3.44–3.55) are managed with a similar technique as for the typical lesions as has been described. The major difference is in

Figure 3.117  Removing avascular bone from the bed of the OCD lesion shown in Figure 3.72 using a power shaver with an 3.5 mm aggressive full radius cutting blade. Dorsal is up, caudal is to the right, the shaver blade placed through a caudolateral portal, and the telescope is looking medially from a lateral portal. Bone of the OCD lesion fills the image below the shaver blade and viable bone has been exposed to produce bleeding seen as red strands. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.118  Aggressive bone removal from an OCD lesion that has produced excessive bleeding beyond what is needed to expose viable bone. The humeral head is seen at the bottom with the blood-filled OCD defect surrounded by cartilage and joint capsule is present across the top of the image. Dorsal is up with caudal to the left and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

initiating the removal process. When the margins of the lesion are not well defined, the margins have not broken through the cartilage, or the lesion cannot be visibly defined the first step is to break the loose cartilage free and define the lesion. This can be done with the 2.0 mm hook probe or more commonly with the curved

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.119  Creating microfractures to improve blood supply using a 70 degree microfracture chisel following superficial removal of bone with a power shaver. The chisel is inserted through a caudolateral portal, the telescope is looking medially from a lateral portal, dorsal is up, and caudal it to the right. The OCD lesion bed is at the bottom of the image with the chisel tip directed down into the bone. The cartilage margin is seen at the far edge of the exposed bone with joint capsule above the instrument. A small area of bleeding from bone is seen to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.120  Creating microfractures using a microfracture chisel in an OCD lesion that did not require bone removal. Smooth bone of the OCD lesion bed is seen across the bottom of the picture with joint capsule in the upper background and a white band of well attached cartilage margin to the left of the instrument. The tip of the chisel is pointed down at the bone in preparation for pressure to penetrate into the bone and produce fractures. The instrument is inserted through a caudolateral portal, the telescope is looking medially from a lateral portal, dorsal is up, and caudal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.121  A fracture fragment, seen as a small fragment of bone to the right of the chisel, produced during the microfracture process. Dorsal is up, caudal is to the left, the instrument is inserted through a caudolateral portal, and the telescope is looking medially from a lateral portal. Joint capsule fills the top of the image and the humeral head OCD lesion is at the bottom with irregular cartilage margin in the background to the right of the chisel tip. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.122  The bed of an OCD lesion after multiple microfractures were created that has produced multiple loose bone fragments and appropriate bleeding. The exposed bone of the humeral head OCD lesion fills the bottom of the image with an irregular roughened surface with multiple areas of minor bleeding. Dorsal is up and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

mosquito forceps used to establish the operative portal (Figures 3.123 and 3.124). Elevation of the loose cartilage in these cases may reveal a small area of abnormal cartilage but most commonly yields a typical larger free cartilage flap. Management of the lesion is dependent on the type of abnormality. Small areas of abnormal cartilage are removed with the hemostat, curettes, rongeurs, or with a power shaver. Lesions that have a

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Figure 3.123  Initial manipulation of an OCD lesion seen in Figure 3.47 as a cartilage indentation without any visible free fragment or lesion margin. A curved mosquito hemostat is used to break through the intact cartilage surface. Dorsal is up, caudal is to the left, and the instrument is inserted through a caudolateral portal with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.124  Further manipulation of the lesion in Figure 3.47 and Figure 3.123 to begin elevation of the loose cartilage flap. Orientation and visible structures are the same as Figure 3.123. The hemostat is being pushed further into the joint to penetrate into the space under the cartilage flap with progression of steps to free and remove the loose cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

typical larger free cartilage flap are managed with the previously described techniques. Arthroliths are uncommonly found in shoulder joints that do not have defined OCD lesions and with no indication of a previous OCD lesion or other pathology that could provide the source of the loose cartilage or osteocartilaginous fragment (Figure  3.125). The arthrolith is accessed with arthroscopic graspers or with the curved mosquito forceps (Figure  3.126) and removed (Figure 3.127).

Figure 3.125  An arthrolith in the caudal joint space of a shoulder joint with no detectable OCD lesion or other possible source. The telescope is looking caudomedially from a lateral portal with dorsal up and lateral to the right. The arthrolith is in the center of the image with a small area of the caudal articular surface of the humeral head to the lower left and a small area of glenoid to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.126  The arthrolith seen in the previous figure is accessed with curved mosquito forceps for removal. Orientation and visible structures are the same as seen in Figure 3.125 and the tip of the instrument inserted through a caudolateral portal is seen to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

An unusual case occurred in a nine‐month‐old spayed female Border Collie that presented with a right front leg lameness with pain on hyperextension and full flexion of the right shoulder joint. There was no left shoulder pain demonstrated with the same manipulation. Radiographs showed bilateral defects in the humeral head indicating bilateral OCD lesions. Bilateral shoulder arthroscopy

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.127  The arthrolith from the previous two figures is being grasped for removal with the curved mosquito forceps. Orientation and visible structures are the came as in the Figures 3.125 and 3.126. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

was performed. A typical OCD‐free cartilage flap was found in the right shoulder that was removed and the bed of the lesion managed arthroscopically. No lesion was found in the left shoulder even with aggressive palpation of the humeral head articular surface (Video 3.6). Thirty days later, this patient was presented with a left front leg lameness and shoulder pain on hyperextension and full flexion. Arthroscopy of the left shoulder revealed a classic OCD lesion with a free cartilage flap and matching defect on the humeral head. The free cartilage was removed, and the bed managed appropriately. Shoulder OCD is commonly a bilateral disease, and arthroscopy typically finds bilateral disease or when unilateral disease is found the normal side does not develop an OCD lesion at a later time. This case is the exception and is the only patient where this was documented in 37 years and hundreds of shoulder arthroscopies. When removal, debridement, and microfractures have been completed, the joint is examined for any loose fragments of cartilage or bone which are removed with hand instruments. To complete the procedure, the joint is irrigated to remove any residual debris using an operative cannula or an egress cannula that is placed into the joint through the operative portal (Figure 3.128) and the cannula is moved around the joint to “vacuum” any debris out of the joint. Suction is not employed on the cannula and the ingress flow pressure combined with the low resistance outflow of the cannula being sufficient to remove debris. Closure is with single skin sutures at the portal sites.

Figure 3.128  An egress cannula in a shoulder joint being used during irrigation to remove debris after OCD lesion extraction. The humeral head OCD lesion is seen at the bottom of the image with an irregular cartilage margin and mild bleeding. Joint capsule fills the top of the picture. The egress cannula is inserted through a caudolateral portal with dorsal up and caudal to the right. The telescope is inserted through a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5.2  Bicipital Tendon Injuries Partial or complete rupture of the bicipital tendon is a relatively common injury to the shoulder joint and is a defined component of the complex group of soft tissue injuries involving this joint. Bicipital tendon injuries can occur as an isolated independent problem or with other injuries to the supportive soft tissues of the joint. The term or diagnosis of “bicipital tendinitis or tenosynovitis” is a misnomer and is not a real entity but clinically significant bicipital tendon pathology is degeneration, tearing, or partial rupture of the tendon. Villus synovial reaction commonly seen around the origin of the bicipital tendon (Figures  3.87, 3.88, 3.91, and 3.129) can occur with any pathology of the shoulder joint and is not specific for or indicative of bicipital tendon pathology. Without arthroscopy diagnosing and managing cases of front leg lameness with shoulder joint pain and normal radiographic findings can be a challenging and frustrating endeavor. Ultrasound, CT, and MRI are advances in diagnostics that are helpful in confirming that there is shoulder joint pathology supporting the need for arthroscopy. Arthroscopy greatly facilitates diagnosis and, in most cases, provides the least traumatic and most effective approach to treatment. Bicipital tendon injuries present as a front leg lameness with shoulder pain and is most commonly seen in large breed dogs. Onset can be acute and severe to chronic and insidious. Sometimes the pain pattern on

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Figure 3.129  Villus synovial reaction around the origin of a normal bicipital tendon in a dog with OCD of the humeral head. The telescope is looking cranially from a lateral portal with dorsal up and lateral to the right. The supraglenoid tubercle articular surface is seen at the top of the picture with humeral head articular cartilage to the lower left. The bicipital tendon extends from its attachment on the supraglenoid tubercle distally to disappear into the bicipital groove at the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

orthopedic examination can order the index of suspicion to specify a bicipital tendon injury but this is not consistent and is not relied on to make a definitive diagnosis. Preoperative radiographs are routinely taken but are not diagnostically helpful in most cases with bicipital tendon injuries except to rule out other entities that show bony changes. Occasionally the tendon will avulse from the scapula with bone attached and create radiographically visible bone fragments. Osteophytes in the area of the bicipital groove and mineralized densities in or around the bicipital groove may or may not be related or specific to bicipital tendon injury (Figure  3.130). MRI, CT, or ultrasound of the shoulder may define bicipital tendon pathology, but normal findings do not rule out a partial tear of the bicipital tendon. Any front leg lameness with shoulder pain is sufficient indication for arthroscopy of the shoulder joint and with the minimally invasive nature of arthroscopy this is the procedure of choice to establish a diagnosis. Arthroscopy for evaluation of the bicipital tendon is performed with a lateral telescope portal (Figure 3.3). Since this is usually an exploratory procedure, an operative portal is not placed until the joint has been examined and an initial diagnosis established indicating the need for an operative portal. Egress for the exploratory portion of the procedure can be achieved with a 20‐ gauge needle placed anywhere that the joint can be

Figure 3.130  An osteophyte in the bicipital groove of a dog with chronic DJD secondary to OCD. The telescope is looking distally from a craniolateral portal with cranial up and lateral to the right. The osteophyte is the white elevated ridge on the right side of the image with bicipital groove cartilage extending from the lower right up past the osteophyte to the upper right area. The cranial surface of the bicipital tendon is seen at the bottom of the image and extends to the lower left. A subtle area of vascular pannus is present on the exposed area of the tendon. Bands of joint capsule are present extending from the upper left distally and are thought to be related to chronic inflammation. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

accessed. If egress through the needle is inadequate or if access is required for placement of a palpation probe, a cranial operative portal is established. A complete examination of the joint is conducted to define all of the pathology present. Bicipital tendon injuries can be obvious (Figure  3.131) with complete rupture and extensive tendon damage or subtle injury with only a few strands of a visible ruptured tendon (Figure 3.132). Injuries occur with (Figure  3.133) or without (Figure 3.132) villus synovial reaction. Villus synovial reaction around the origin of the tendon (Figures 3.87, 3.129, and 3.133) or in the bicipital groove (Figure 3.129) may obscure the tendon and make examination difficult. Use of the palpation probe (Figure  3.134) may facilitate examination and occasionally debridement of the villus synovitis will be required for an accurate determination. It is very important to remember that the bicipital tendon may be normal under the reactive synovium, any shoulder pathology can cause villus synovial reaction around the bicipital tendon, and clinically significant pathology causing the synovial reaction, shoulder pain, and lameness may lie elsewhere in the joint. It is also important to remember that bicipital tendon injury can occur by itself or in combination with other injuries to the soft tissue supportive structures of the shoulder joint.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.131  A completely ruptured bicipital tendon that demonstrates obvious severe injury. The telescope is looking cranially from a lateral portal and dorsal is up with lateral to the left. The tendon is split into two bundles seen as long round structures in the center of the image and is completely separated from the supraglenoid tubercle that is at the top of the picture. Humeral head articular cartilage is visible curving across the bottom of the figure with fine frayed cartilage representing Grade I chondromalacia. There is moderate villus reaction on the surface of the tendon and on the joint capsule behind and to the right of the tendon remnants. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.133  A partially ruptured bicipital tendon with extensive villus synovial reaction that partially obscures the tendon damage. The telescope is looking craniomedially from a lateral portal and dorsal is to the upper right with lateral to the upper left. The tip of the supraglenoid tubercle is in the upper right with the tendon extending toward the lower left into the bicipital groove. Humeral head articular surface curves around the lower edge of the image. Villus synovial reaction fills the center of the picture with ruptured tendon seen to the upper right of the reactive tissue as multiple white strands. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.132  A minimally ruptured bicipital tendon seen as a small number of fine damaged strands at the bone tendon junction and as an irregular contour of the tendon distal to its origin. A small portion of supraglenoid tubercle is at the upper right with tendon extending from the upper left distally to the lower right of the image. The telescope is looking craniomedially from a lateral portal and dorsal is up with lateral to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.134  A 2.0 mm palpation probe placed through a craniolateral operative portal is being used to evaluate integrity of the bicipital tendon in the shoulder of a dog with lateral labrum avulsion and a subscapularis injury. There is a small amount of villus synovial reaction at the origin of the tendon with no tendon damage. Up is dorsal and lateral is to the right with the telescope looking craniomedially from a lateral portal. The tip of the supraglenoid tubercle is at the top of the image, the bicipital tendon seen as the vertical tubular white structure on the right side, craniomedial joint capsule is to the left of the tendon, humeral head articular cartilage is at the lower left with the medial end of the transverse humeral ligament circling around behind the bicipital tendon. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Avulsion of the bicipital tendon from the supraglenoid tubercle is another form of bicipital tendon injury with a presentation similar to rupture of actual tendon. The diagnostic and arthroscopic approaches are also the same as for bicipital tendon ruptures. Ultrasound, CT, or MRI may differentiate the two injuries before arthroscopy. Findings with arthroscopy reveal separation of the tendon from its boney attachment that can be minor and easily visible (Figure 3.135), major and easily visible (Figure 3.136), or hidden within the origin of the tendon (Figure 3.137) that requires probe manipulation to define the injury (Figure 3.138). Avulsion of the bicipital tendon also occurs with separation of bone with the tendon from an injury or as part of the ununited supraglenoid tubercle syndrome (USGT). Differentiation of the two etiologies is not possible in many cases. See more under USGT. In addition to tendon damage at its origin, with rupture or avulsion changes are also seen in the body of the tendon distal to its origin. Splitting of the tendon into longitudinal strands is one of the more common findings with intact (Figure  3.139), partially ruptured strands (Figure  3.140), or completely ruptured strands (Figure  3.131). Tendon remodeling is also seen with chronicity and apparent attempts of the tendon to heal (Figure 3.141). Loss of tension on the tendon can also be

Figure 3.136  Avulsion of a significant portion of the bicipital tendon from the supraglenoid tubercle in a shoulder joint with multiple other soft tissue injuries. The supraglenoid tubercle is to the upper left, there is a step of tendon tissue away from the bone and the tendon extends to the lower right from the tip of the tubercle, humeral head articular cartilage is at the bottom, and lateral labrum separation is seen in the upper right portion of the image. Villus ghosts are seen to the far left and far right. Lateral is to the right with dorsal up and the telescope is looking craniomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.135  Partial minor avulsion of the bicipital tendon from the supraglenoid tubercle seen as irregularity of tendon tissue at the bone tendon junction. This was the only abnormality seen in this joint and there is no villus synovial reaction. The telescope is looking craniomedially from a lateral telescope portal and dorsal is up with craniolateral to the left. Humeral head articular cartilage is at the bottom with supraglenoid tubercle at the top and the tendon filling the left side of the image between the two cartilage surfaces. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.137  Avulsion of the origin of the bicipital tendon that cannot be seen from this external view. There is minimal color change in the synovial tissue around the origin of the bicipital tendon and minimal change in the contour of the tendon. Villus ghosts are seen on the right side of the proximal tendon. The very tip of the supraglenoid tubercle is visible to the upper left with the tendon extending obliquely from the tubercle to the lower right. Proximal is up, lateral is to the left and the telescope is looking craniomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.138  Identification of internal tendon avulsion in the previous image using the palpation probe to apply pressure to the tendon. Separation of the tendon is seen as a ragged line of frayed tendon fibers with a line of darker exposed bone running obliquely across the center of the image. The probe is visible in the upper left-hand portion of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.139  A split bicipital tendon with the main portion of the tendon on the left side of the image and a split strand running vertically across in the right center of the picture. There are no visible ruptured tendon fibers. Craniolateral is to the right and dorsal is up with the telescope looking cranially from a lateral portal. A small portion of the tip of the supraglenoid tubercle is seen to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

seen with proximal rupture or avulsion (Figure 3.142). Damage to the joint capsule extension around the bicipital tendon has also been reported (Innes and Brown 2004).

Figure 3.140  A split strand of bicipital tendon that is also partially ruptured. The telescope is looking cranially from a lateral portal and dorsal is up with lateral to the right. The main portion of the bicipital tendon is filing the left side of the image with the split portion running vertically to the right and ruptured strands projecting to the left from the tendon strand. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.141  Remodeling of a chronically ruptured bicipital tendon suggesting attempted healing. The supraglenoid tubercle is at the top of the picture with the tendon running vertically down the center, and humeral head articular cartilage to the lower right. Proximal is up, lateral is to the left, and the telescope is looking cranially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Isolated partial rupture of the bicipital tendon without damage to other soft tissue supporting structures is treated by transection of the tendon at its origin within the shoulder joint under arthroscopic guidance (Bergenhuyzen and Vermote 2010; Wall and Taylor 2002) (Video 3.7). A craniolateral operative portal is used for this procedure (Figure  3.3). And if this portal has not

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Figure 3.142  A loose bicipital tendon due to proximal avulsion that is not straight and has visible cross striations on its surface. The avulsion is not evident in this picture. The telescope is looking distally from a craniolateral portal with proximal up and lateral to the right. The tendon fills the left portion of the image and runs distally down the bicipital groove with humeral head articular surface to the lower right and discolored joint capsule to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

already been established during exploration, it is placed at this time using a 20‐gauge hypodermic needle placed into the joint space lateral to the origin of the tendon (Figure  3.6). When the site for this portal has been established, a stab incision is made into the joint with a no. 11 scalpel blade with the blade passed parallel to the needle (Figure  3.143). A curved mosquito hemostat is passed through the incision to form the portal and instrumentation for tendon transection is inserted. Both the skin entry location and the angle of insertion are important to facilitate tendon transection. Instruments that can be used for tendon transection include an 18 gauge 1.5″ hypodermic needle, a no. 11 scalpel blade (Figures  3.144 and  3.145), monopolar radiofrequency electrocautery (Figure 3.146), or bipolar radiofrequency electrocautery (Figures 3.147 and 3.148). Bipolar radiofrequency electrocautery specifically designed for arthroscopy (VAPR) is the most effective technique when there is any synovial reaction or visible vascularity at the transection site because this system controls hemorrhage during the tenotomy (Video 3.7). In cases with no synovial reaction or visible vessels (Figures 3.132, 3.135–3.137) around the tendon at the transection site, a no. 11 scalpel blade works very well (Figures  3.144 and  3.145). If a scalpel blade is used in the presence of synovial reaction or visible vascular supply (Figures 3.131, 3.133, 3.141, and 3.146), there is typically

Figure 3.143  A no. 11 blade is inserted into the joint parallel to the needle to insure accurate portal placement. In this image the telescope is looking cranially from a lateral portal and dorsal is up with lateral to the right. The needle and blade are seen entering the joint from the upper right through a craniolateral operative portal. Supraglenoid tubercle is seen at the top, humeral head articular surface at the bottom, and ruptured tendon fibers are to the left of the scalpel blade. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.144  Transection of a bicipital tendon with internal avulsion using a no. 11 scalpel blade placed through a craniolateral portal. The blade is correctly positioned to allow transection with both insertion angle and axial rotation perpendicular to the tendon. Cutting with a cold blade is possible because there is no increase in vascularity due to synovial reaction. Dorsal is up and lateral is to the right with the telescope looking cranially from a lateral portal. The articular surface of the supraglenoid tubercle is to the upper left with the humeral head to the lower right and the tendon is crossing the image at an oblique angle from upper left to lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

sufficient bleeding to obscure the visual field and make completion of the transection difficult to impossible. Use of electrocautery eliminates the issue of bleeding. Tenotomy using the VAPR bipolar radiofrequency

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.145  After completion of bicipital tendon transection from the previous image. There is a smooth clean transverse cut perpendicular to the tendon with the no. 11 scalpel blade that is still visible in the joint as a dark straight line running partially across the figure from upper right to lower left. Visible structures, orientation and telescope position are the same as Figure 3.144. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.146  Cutting a partially ruptured bicipital tendon with monopolar radiofrequency electrocautery using an arthroscopic adaptor placed into the joint through the craniolateral operative portal. Radiofrequency is used in this patient due to the vascularity of the villus synovial reaction. The telescope is looking cranially from a lateral portal with dorsal up and lateral is to the left. A small portion of supraglenoid tubercle is seen at the far right and the remainder of structures are obscured by the pathology present. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

system seals the blood vessels and vaporizes the tissue to transect the tendon (Figures 3.149 and 3.150) without bleeding and leaving minimal compromised tissue (Figure 3.151).

Figure 3.147  A VAPR bipolar radiofrequency system using a 2.3 mm diameter wedge effect electrode is positioned in the joint through the craniolateral operative portal in preparation for cutting a partially ruptured bicipital tendon. The telescope is looking cranially from a lateral portal with lateral to the left and dorsal up. Humeral head cartilage is present across the bottom of the image with a small portion of supraglenoid tubercle indistinctly seen in the upper right. Clear visualization of the tendon is obscured by synovial reaction and tendon pathology. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.148  A VAPR bipolar radiofrequency system 2.3 mm diameter side effect electrode is placed into the shoulder joint through the craniolateral operative portal in preparation for transecting a partially ruptured bicipital tendon. Dorsal is up, lateral is to the right, and the telescope is looking cranially from a lateral portal. Supraglenoid tubercle is at the top of the image, humeral head is visible at the bottom, ruptured tendon fibers are seen behind and to the left of the VAPR electrode. The electrode is rotated 180 degrees so that the tendon cutting is away from the telescope or the electrode is positioned cranial to the tendon with the rotation unchanged so that the tendon is cut toward the telescope. Both techniques work and which one is used is determined by conditions of the individual patient. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.149  Cutting a bicipital tendon using a 2.3 mm diameter wedge effect VAPR electrode. The telescope is looking cranially from a lateral portal, dorsal is up, lateral is to the left, and the electrode is inserted through a craniolateral portal. The proximal end of the cut tendon is at the top and the cut surface of the distal end is at the bottom of the image with a small amount of residual tendon fibers and mesotendon still intact between the tendon ends. A small amount of tissue charring is present along the cranial margin of the distal cut and on the adjacent joint capsule. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.150  Completion bicipital tendon transection in the patient from the previous figure after cutting the residual tendon fibers and the mesotendon to completely free the distal tendon. Orientation and telescope position are the same as the previous image Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

When transecting the bicipital tendon, it is important to cut all attachments of the tendon not only to the bone of the supraglenoid tubercle but also to the soft tissues so that the cut end of the tendon is completely free to retract into the bicipital groove (Figure  3.151). The bicipital tendon is covered with synovium that comes off the tendon on its cranial surface to form the

Figure 3.151  The completely transected bicipital tendon free of all attachments and retracted an appropriate distance into the bicipital groove. There is no bleeding from the cutting process due to the action of the VAPR and there is minimal compromised tissue from the radiofrequency application. Orientation and telescope position are the same as the previous two figures. The cut end of the distal tendon is visible in the lower center of the image with a small amount of humeral head at the lower right and cranial joint capsule filling the top of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.152  Mesotendon of the bicipital tendon visible as a vertical band of translucent tissue cranial and proximal to the transected tendon end that is seen in the lower right of the image. Dorsal is up, lateral is to the left, the telescope is looking cranially from a lateral portal, and a no. 11 scalpel blade inserted through a craniolateral portal is present to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

mesotendon and attaches to the cranial joint capsule (Figure  3.19). If this band of tissue is left intact (Figures 3.152 and 3.153), it is stretched or torn causing pain until the tendon completes its retraction. This tissue must be cut (Figure  3.154) to allow adequate

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.153  A 2.0 mm hook probe placed through the craniolateral portal is being used to improve definition of the uncut tissue in the same patient as the previous figure. Orientation and telescope position are the same as in the previous figure. The cut end of the tendon seen at the bottom of the image is tethered in place by the mesotendon preventing full retraction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.155  An appropriately retracted cut bicipital tendon after completion of mesotendon transection from the same patient is in Figures 3.152 to 3.154. The telescope has been moved from the lateral portal to the craniolateral portal and is looking distally with cranial up and lateral to the left. The cut tendon end fills the center of the image with joint capsule across the top and bicipital groove cartilage across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Kenter  2005). Since then it has been determined that screw fixation is not needed. In personal experience, patients recovered faster without screw fixation than they had with screw fixation.

3.5.3  Soft Tissue Injuries of the Shoulder with or Without Shoulder Instability

Figure 3.154  The residual mesotendon is being cut using a 2.3 mm diameter side effect VAPR electrode in the same shoulder as Figures 3.152 and 3.153. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

retraction of the cut tendon (Figure 3.155) and to speed pain reduction after bicipital tendon transection. Following completion of tendon transection, the joint is irrigated with saline to remove debris. If there is a significant synovial reaction, intra‐articular stem cells or steroids are considered. Primary treatment of bicipital tendon injuries with intra‐articular stem cells or with injection directly into the tendon, lesion is an additional option for managing this pathology. Closure is with single skin sutures at the portal sites. Screw placement to fix the transected bicipital tendon was standard operative procedure when transection was performed as an open procedure and when transection was first performed with arthroscopy (Cook and

The shoulder joint is comprised of two slightly curved bone surfaces held together by a cuff of multiple soft tissue structures including the medial glenohumeral ligament, subscapularis tendon, bicipital tendon, supraspinatus tendon, infraspinatus tendon, lateral labrum, lateral glenohumeral ligament, and joint capsule. Any or all of these structures can be damaged resulting in lameness, joint pain, instability, and degenerative joint disease (Bardet  1998). Bicipital tendon injury has been discussed separately from this group of injuries because its treatment is significantly different from the treatment of injuries to the other soft tissue structures. This group of soft tissue injuries is also a relatively new diagnosis that has evolved with the increased use of arthroscopy as a diagnostic procedure. The pathology of these injuries is still being defined, diagnostic techniques developed, and approaches to treatment are being investigated. Soft tissue injuries of the shoulder joint present as a front leg lameness with shoulder pain that can vary from marked and obvious to subtle and inconsistent. Onset ranges from acute and severe to chronic and

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insidious. Instability of the shoulder joint may be ­present with cranial to caudal drawer instability, medial to lateral drawer instability, and increased range of shoulder joint abduction. Manipulation of the shoulder joint for instability is conducted in both the awake and anesthetized patient. Preoperative radiographs are routinely taken but are not diagnostically helpful in most cases except to rule out other entities that typically show radiographic changes. Generalized degenerative changes may be seen on shoulder radiographs in cases with chronic soft tissue injury with or without shoulder joint instability but these are not diagnostically specific findings. MRI, CT, or ultrasound of the shoulder may be helpful in defining shoulder joint pathology, but normal findings do not rule out soft tissue injuries. In the case with subtle evidence of shoulder involvement, a joint tap can be informative. If an increased quantity of fluid is obtained, this confirms the presence of shoulder pathology and confirms the indication for arthroscopy. A front leg lameness with shoulder pain is a sufficient indication for arthroscopy of the shoulder joint and, with the minimally invasive nature of arthroscopy, this is the procedure of choice to establish a diagnosis. Diagnosing and managing cases of front leg lameness with shoulder joint pain with normal or nonspecific radiographic findings can be a challenging and frustrating endeavor. Differentiating specific injuries with physical examination is difficult (Devitt and Neely 2007; Jones and Howard  2019; Kunkel and Rochat 2008b; Mitchell and Innes  2000). Arthroscopy greatly facilitates diagnosis and, in some cases, provides the least traumatic and most effective treatment. Arthroscopic exploration of the shoulder joint for suspected soft tissue injury is performed through a lateral telescope portal (Figure  3.3) with initial egress through a 20‐gauge hypodermic needle placed cranially (Figure  3.6) or caudally (Figure  3.8). When the initial examination has been completed and if a significant pathology is found, an appropriate operative portal is placed to access the lesions. A craniolateral operative (Figure 3.3) portal is the most commonly used site for soft tissue injuries. Currently defined lesions include injuries to all of the supporting soft tissue structures of the joint. The medial glenohumeral ligament (Figures  3.12, 3.14, and  3.29) is commonly involved with a wide variety of injuries ranging from mild focal easily seen lesions (Figure  3.156), mild subtle lesions requiring joint abduction and probe manipulation to identify (Figure  3.157), mild diffuse lesions (Figure  3.158), moderate focal injuries (Figure  3.159), severe focal injuries (Figure  3.160), and severe diffuse injuries (Figure 3.161). Any of the variety of injuries can

Figure 3.156  A mild focal easily seen injury of the cranial arm of the medial glenohumeral ligament demonstrated as ruptured free ligament fibers. The image is rotated with dorsal to the left and cranial down with the telescope looking medially from a lateral portal. Glenoid articular surface is to the left and humeral head is to the right with the ligament angled between the two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.157  A mild focal medial glenohumeral ligament injury at its origin that required joint abduction and probe manipulation to identify. The telescope is looking medially from a lateral portal, dorsal is up, cranial is to the right, and the probe is inserted through a craniolateral portal. The glenoid articular surface fills the top of the image. The ligament extends from the medial margin of the scapula at far right obliquely under the probe with visible intact fibers in the lower portion and ruptured fibers seen to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

be acute (Figures 3.156–3.160), chronic (Figure 3.162), or a combination of acute and chronic (Figure 3.161). Subscapularis tendon injuries are seen with the same range of damage that is seen with medial glenohumeral ligament injuries. Mild acute focal lesions (Figure 3.163), moderate acute injuries (Figure 3.164), and severe acute

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.158  Mild diffuse injury to the cranial arm of the medial glenohumeral ligament seen as fine free fibers over the lateral surface of the ligament. The humeral head is at the bottom with the glenoid across the top and the ligament is angling obliquely between the two bones. Dorsal is up and cranial is to the right with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.159  Moderate focal injury of the cranial arm of the medial glenohumeral ligament seen as loose fiber bundles coming from its dorsal margin with one extending caudally parallel to the ligament and one hanging down across the intact portion of the ligament. Dorsal is up with cranial to the left and the telescope is looking medially from a lateral portal. The medial portion of the glenoid is seen across the top of the image with humeral head at the bottom. The cranial arm of the medial glenoid ligament sits obliquely across the center of the figure with the caudal arm curving up to the glenoid at the far right and the subscapularis tendon is seen medial to the cranial arm of the medial glenohumeral ligament to the lower left. This view requires significant abduction of the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.160  Severe focal injury to the medial glenohumeral ligament with extensive fiber rupture. The telescope is looking medially from a lateral portal with dorsal up. Glenoid articular surface fills the top of the image with a small portion of humeral head at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.161  Severe diffuse injury of the medial glenohumeral ligament with acute and chronic components. Dorsal is up with cranial to the right and the telescope is looking medially from a lateral portal. Humeral head is seen at the bottom of the image with the damaged ligament extending from the lower left to the upper right, reactive joint capsule is to the upper left, and the glenoid is indistinctly visible to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

damage (Figure  3.165) with visible ruptured fibers. Subscapularis tendon injuries are also seen as splitting of the tendon with a range of severity including mild (Figure  3.166), moderate (Figure  3.167), to severe (Figure  3.168) without visible ruptured tendon fibers. Injuries to the subscapularis tendon are also seen with a

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Figure 3.162  A chronic severe diffuse medial glenohumeral ligament injury with remodeled blunted fibers and vascular invasion of the ligament. Dorsal is up and the telescope is looking medially from a lateral portal. Humeral head is seen at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.163  An acute mild focal subscapularis tendon injury with fraying at the tendon’s insertion. Dorsal is up and cranial is to the left with the telescope looking medially from a lateral portal. Humeral head is to the lower right and subscapularis tendon fills the upper portion of the image, behind the line of free fibers, seen as indistinct fibers due to joint capsule reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

combination of visible ruptured fibers and splitting of the tendon fibers (Figure  3.169). Chronic injuries are also seen with increased vascularity of the tendon (Figure  3.170), remodeling of the injured tendon (Figure  3.171), and changes of ruptured tendon fibers with loss of sharp fibers ends and cross striations seen in acutely ruptured fibers (Figure  3.172). Synovial reactions are also seen associated with subscapularis tendon injuries either related to the tendon injury itself or to generalized inflammation within the joint and unrelated

Figure 3.164  Acute moderate injury of the subscapularis tendon with visible ruptured fibers. The telescope is looking medially from a lateral portal with cranial to the right and dorsal up. A small area of humeral head is in the lower left, the medial margin of the glenoid is to the upper right. Craniomedial joint capsule fills the right center and frayed subscapular tendon is seen angling across the image from upper left to lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.165  Severe acute injury to the subscapularis tendon with visible ruptured fibers to the right and bundles of splint tendon to the left. Dorsal is up with cranial to the right and the telescope is looking medially from a lateral portal. The damaged tendon fills the image except for a small portion of humeral head seen at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

to the tendon injury. This synovial reaction is most significant when it covers the tendon interfering with examination for injuries and is seen as hyperemic villi (Figure 3.173) or as pale villi ghosts (Figure 3.174). Supraspinatus tendon pathology (Degeneration/ Mineralization/Partial Rupture) can be a source of lameness and shoulder pain (Lafuente and Fransson  2009).

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.166  Mild subscapularis tendon injury demonstrated as splitting of the tendon fibers rather than visible ruptured fibers. Dorsal is up with cranial to the right and the telescope looking medially from a lateral portal. The cranial arm of the medial glenohumeral ligament is seen running obliquely across the upper left of the image, a small portion of humeral head is at the bottom and the subscapularis tendon extends from behind the medial glenohumeral ligament obliquely to the lower right. The cranial fibers are normal with splitting of the fibers in the caudal half of the exposed tendon. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.167  Moderate splitting of subscapularis tendon fibers without visible fiber rupture. The tendon fills the image except for a small portion of humeral head at the bottom and medial glenohumeral ligament to the upper right. Dorsal is up and cranial is to the left with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Radiographs may be normal or may show mineralized densities in the area of the bicipital groove and greater tubercle. CT, MRI, and ultrasound may also be helpful in identifying abnormalities in the supraspinatus tendon. Supraspinatus tendon injuries can also be identified

Figure 3.168  Severe splitting of the subscapularis tendon with loss of tendon structure between the remaining tendon bands and without visible ruptured fibers. The remaining tendon bands are running vertically at the far left and center right with a gap between the two where tendon is missing. Injury of the cranial arm of the medial glenohumeral ligament is also seen at the top of this image as an irregular mass for ruptured fibers. Dorsal is up and cranial is to the right with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.169  Severe splitting of the subscapularis tendon with loss of tendon structure and visible ruptured tendon fibers. Glenohumeral ligament is seen in the upper right with damaged tendon filling the remainder of the image. A band of intact ligament with split fibers is visible running vertically across the center with ruptured fibers distally and an indistinct portion of damaged but intact tendon to the far left. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

using arthroscopy by looking in the craniolateral portion of the joint cranial to the lateral collateral ligament (Figure 3.31) and lateral to the origin of the bicipital tendon. The normal tendon cannot be seen as it is outside the joint capsule with the joint capsule fused to the

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Figure 3.170  Increased superficial vascular pattern seen to the right on a chronically injured subscapularis tendon with an irregular loose and indistinct fiber pattern to the left where the tendon is not covered with the vascular reaction. This image also shows injury to the medial attachment of the joint capsule to the medial glenoid rim as mild fraying at the upper left and a mild vascular pattern is seen on the ventral margin of the medial glenohumeral ligament as it angles obliquely across the image from the top to the lower left. Dorsal is up with cranial to the right and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.171  Remodeling of the subscapularis tendon indicating chronicity with an area of fine free fibers indicating repeated injuries over time. The tendon fills the image except for a small rim of medial glenohumeral ligament extending from lower left to the upper left of the image and humeral head across the bottom. Dorsal is up and cranial is to the right with the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

tendon. This area of the joint is not easy to see from the lateral telescope portal with the standard 30° arthroscope. Use of an arthroscope with an angle greater than 30° is usually required, 45 or 70°, or the 4.0 mm Endocameleon

Figure 3.172  Ruptured subscapularis tendon fiber bundles showing chronic changes of blunting, thickening, shortening, and loss of cross striations. A portion of intact tendon is visible as a vertical white band to the left of the ruptured bundles with tendon to the right of the bundles obscured by villus ghosts. An instrument is seen at the bottom of the image and the medial glenohumeral ligament covered with synovial vascular pattern fills the upper portion of the picture. Dorsal is up and cranial is to the right. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.173  Hyperemic villus synovial reaction hiding a subscapularis tendon injury. The telescope is looking cranially from a lateral portal with dorsal to the upper right and cranial to the upper left. The glenohumeral ligament is seen running across the right side of the image, humeral head is to the lower left, craniomedial joint capsule is to the upper left, and the subscapularis tendon covered with villus reaction filling the center with normal fibers visible at its insertion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

with an adjustable angle from 15 to 90° can be used. With injury of the tendon, the joint capsule is damaged with the tendon allowing the damaged tendon to be seen in the joint with the 30° telescope (Figures 3.175 and 3.176) or with the 4.0 mm Endocameleon (Figure 3.177). Open

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.174  Pale villi or ghosts obscuring visualization of an injured subscapularis tendon are seen filling the center of the image. Ghost villi are seen when the acute phase of inflammation has passed, and chronic changes have occurred. The medial glenohumeral ligament with changes suggesting chronic injury without ruptured fibers is seen running across the top of the figure with a small potion of humeral head at the bottom. Cranial is to the left with dorsal up and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.175  A ruptured supraspinatus tendon visible in the craniolateral quadrant of the joint seen with the arthroscope placed through a lateral telescope portal and looking cranial with the 30 degree angle directed laterally. The ruptured tendon is remodeled with blunted features and the whiter area in the center of the image is mineralized tissue. Dorsal is up, lateral is to the right, and humeral head fills the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

surgical debridement of the lesions has been performed with variable results. Stem cell therapy with direct injection into the tendon, activity restriction, use of the shoulder support system, and physical rehabilitation is the currently recommended approach to treatment. Avulsion of the lateral labrum is also visible with arthroscopy using the lateral telescope portal and

Figure 3.176  A second view of the injured supraspinatus tendon seen in the previous figure with the telescope further cranially showing a more acute portion of the injury. Dorsal is up and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.177  An injured supraspinatus tendon seen using the Endocameleon arthroscope. The telescope was inserted through a lateral portal and directed cranially with the lens angled laterally to 90 degrees. The ruptured tendon is seen as loose fibers to the upper right. Villus synovial reaction around the origin of a normal bicipital tendon is seen in the center of the image with supraglenoid tubercle at the upper left and humeral head cartilage across the bottom. Dorsal is up and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the  30° arthroscope, 45° or 90° arthroscopes, or the Endocameleon. As an alternative a craniomedial telescope portal is placed but is much more difficult without positioning the patient in dorsal recumbency with the legs hanging for preparation, draping and for the procedure. Lateral labrum injuries are seen as frayed tissue at the attachment of the cartilaginous labrum to bone (Figures  3.178 and  3.179), separation of the labrum from bone (Figure 3.180), and avulsion of bone

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Figure 3.178  Frayed tissue at a site of lateral labrum injury looking cranially from the lateral telescope portal with a 30-degree arthroscope angle directed dorsally. Dorsal is up and lateral is to the left. The lateral margin of the glenoid articular surface fills the lower right of the image with joint capsule to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.179  Frayed tissue indicating lateral labrum avulsion looking medially from the lateral telescope portal using a 30-degree arthroscope angled up. Dorsal is up. The glenoid articular surface fills most of the image with humeral head at the bottom and labrum across the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

with the labrum (Figure  3.181). Removal of avulsed bone fragments can be achieved with arthroscopy (Figures 3.182 and 3.183). Complete assessment of the lateral labia and lateral glenohumeral ligament may require placement of a craniomedial telescope portal through the space between the origin of the bicipital tendon and the subscapularis tendon. An adequate evaluation may also be achieved with an Endocameleon arthroscope or a 70° arthroscope from the lateral telescope portal. The joint capsule is commonly involved with other soft tissue injuries either as a visible injury or secondary

Figure 3.180  Separation of the lateral labrum from the bone of the lateral margin of the glenoid seen as frayed tissue at the junction of cartilage and bone. The labrum is at the far right of the image with supraglenoid tubercle to the upper left, humeral head articular surface to the lower left, bicipital tendon is in the background to the lower right and a 20 gauge hypodermic needle placed to establish a craniolateral portal. Dorsal is up, lateral is to the right and the telescope is looking cranially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.181  Avulsion of the lateral labrum with fracture of a bone fragment from the lateral margin of the glenoid. A 20-gauge needle was placed to define an operative portal site and extends through the fracture line. Dorsal is up with lateral to he left and the telescope is looking cranially from a lateral portal. The bone fragment is in the irregular tissue to the left of the needle, a small portion of glenoid with the fracture defect is to the right of the needle, humeral head articular surface is at the bottom, lateral glenohumeral ligament is to the lower left, and the bicipital tendon is seen in the background to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

to inflammation. Joint capsule tearing or avulsion from the caudal margin of the glenoid is seen as an isolated injury or in combination with other injuries. The injuries can be minimal and focal (Figure 3.184), moderate

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.182  The tip of a no. 11 scalpel blade is positioned through the fracture line in the joint to cut the soft tissue attachments of the avulsed bone fragment to free it from the scapula. Orientation is the same as the previous figure with slight angulation change of the telescope to expose more of the glenoid articular surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.184  A minor small focal joint capsule injury at its attachment to the caudal margin of the glenoid seen as a few loose stands of tissue. Dorsal is up and caudal is to the left with the telescope looking caudally and medially from a lateral portal. The glenoid articular surface fills the upper right with joint capsule to the upper left and humeral head is visible across the bottom of the image. The tip of a 20-gauge needle is seen in the background at the junction of bone and joint capsule that was placed in preparation for establishing a caudolateral operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.183  The bone defect in the lateral margin of the glenoid after removal of the avulsed bone fragment. Orientation and telescope position are unchanged from the previous figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

and focal (Figure  3.185) or diffuse (Figure  3.186), or severe and extensive (Figure  3.187). The other area of the joint capsule where injuries are seen is on the medial margin of the glenoid (Figure 3.188). Injuries in this area can be confused with medial glenohumeral ligament injuries and abduction of the joint may be needed to differentiate the two injuries (Figure  3.189). Secondary inflammatory changes in the joint capsule occur with soft tissue injuries and are expressed as an increased vascular pattern on the surface of soft tissue structures (Figure  3.190), villus synovial reactions (Figures  3.133, 3.173, 3.191, and  3.192), and mass‐like villus reactions (Figures 3.193 and 3.194). With chronicity, the reactive villi lose their hyperemia and vascular appearance to

Figure 3.185  A moderate severity focal injury of the joint capsule at its attachment to the caudal rim of the glenoid seen as a cluster of free tissue fibers. The glenoid articular surface is visible behind the damaged tissue toward the upper right with the humeral head to the lower right. The telescope is looking caudomedially from a lateral portal with dorsal up and caudal to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

become villus ghosts (Figures 3.174 and 3.195). Fibrosis can develop in the joint capsule tissue following injury or inflammation as diffuse mild thickening (Figure3.196), defined ridges of fibrosis with surrounding diffuse

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Figure 3.186  Moderate severity diffuse injury along a significant length of the joint capsule attachment to the caudal glenoid seen as frayed tissue strands. Dorsal is up with caudal to the left and the telescope is looking caudomedially from a lateral portal. The glenoid is seen extending to the right from the damaged tissue with a small portion of glenoid at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.187  Severe injury of the caudal joint capsule at its attachment to the caudal glenoid with cartilage damage and exposed bone on the caudal margin of the glenoid. Dorsal is up with caudal to the left. The telescope is looking caudomedially from a lateral portal. A small portion of glenoid articular cartilage is to the right with a margin of frayed tissue and a stripe of exposed glenoid bone seen as the pale tan area to the left of the cartilage edge. Frayed joint capsule is arching from the far left down and to the right to disappear behind the humeral head that is at the bottom of the image. A small area of villus synovial reaction is visible to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

involvement (Figure  3.197) sometimes including villus synovitis (Figure  3.198), or as joint capsule distortion from irregular fibrosis (Figure 3.199). Treatment approaches for soft tissue injuries have included open surgical reconstructions (Pettitt et al. 2007),

Figure 3.188  Injury of the attachment of medial joint capsule to the medial margin of the glenoid is seen between the medial glenohumeral ligament and the glenoid articular surface. The telescope is looking medially from a lateral portal with dorsal up and caudal to the left. A small portion of humeral head is at the bottom of this image with medial glenohumeral ligament running obliquely across the center, and glenoid filling the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.189  Abduction of the joint seen in the previous image shows separating the normal glenohumeral ligament from the joint capsule injury. Orientation and telescope position are unchanged from the previous image. The normal medial glenohumeral ligament is seen running obliquely across the bottom right of the image with the lateral surface at the very bottom, the dorsal surface above this and extending into the background below the margin of the glenoid with the frayed joint capsule attachment, and the glenoid articular surface fills the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

arthroscopy guided surgical reconstruction (Penelas et al. 2018a, b; Pettitt and Innes 2008; Ridge et al. 2014), arthroscopy‐guided thermal modification (heat shrinking), conservative medical management with activity

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.190  An increased irregular vascular pattern seen on the lateral surface of the medial glenohumeral ligament in a shoulder with soft tissue injuries. The ligament extends across the middle of the image from lower right to upper left and is normal. The acetabular articular surface fills the top of the image, the subscapularis tendon is to the lower left below the medial glenohumeral ligament, dorsal is up, cranial is to the left, and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.191  Villus synovial reaction covering a large area of caudomedial joint capsule of a shoulder with soft tissue injuries. The telescope is looking caudomedially from a lateral portal with dorsal up and caudal to the right. A small portion of humeral head is at the bottom with joint capsule filling the remainder of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

restriction and anti‐inflammatory drugs (steroids or NSAIDs), shoulder hobbles or shoulder support systems, physical therapy, and stem cell therapy. Optimum treatment and case selection for the various treatment approaches have not yet been well defined. Considerable additional work is needed to establish appropriate criteria for most effective application of each treatment

Figure 3.192  Marked villus synovial reaction in the craniomedial joint space of a shoulder joint with soft tissue injuries. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. Medial glenohumeral ligament is to the upper right with humeral head across the bottom and reactive synovial tissue filling the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.193  A mass like villus reaction at the origin of the bicipital tendon in a shoulder joint with other soft tissue injuries. The mass is in the center of the image with supraglenoid tubercle to the upper left, humeral head angled across the bottom, and bicipital tendon indistinctly visible to the right. The telescope is looking craniomedially from a lateral portal with dorsal up and cranial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

method. Current approaches are to employ arthroscopic or open surgical reconstruction only when there is complete or substantial rupture of one or more structures resulting in significant joint instability. Arthroscopic treatment with heat modification of tissues has fallen out of favor but was employed when there was partial rupture of the medial glenohumeral ligament or subscapularis tendon with sufficient residual tissue to

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Figure 3.194  A smaller mass like villus reaction in a shoulder joint with soft tissue injuries. Dorsal is up with cranial to the left and the telescope is looking craniomedially from a lateral portal. A small portion of medial glenohumeral ligament is seen at the top with the subscapularis tendon filling the remainder of the image and the hyperemic villus reaction to the right of center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.195  Multiple large villus ghosts surrounding the origin of the bicipital tendon in a shoulder joint with multiple chronic soft tissue injuries. Dorsal is up with cranial to the left and the telescope is looking craniomedially from a lateral portal. Supraglenoid tubercle is seen at the top, humeral head cartilage is to the lower right, and bicipital tendon is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

provide joint support following thermal modification (Figures 3.163, 3.173, and 3.200). Thermal modification of tissue is performed with a bipolar radiofrequency device specifically designed for arthroscopy (Figures 1.14– 1.16) using either a handpiece with a thermocouple tip (Figure 3.201) that controls tissue temperature or a standard handpiece (Figure 3.202) without temperature control. The preferred instrument is the thermocouple tip as it reduces the chances of overheating tissues. Caution must still be used because overuse causes excessive tissue damage with excessive loss of tissue strength, delayed

Figure 3.196  Scattered areas of diffuse joint capsule fibrosis and in the caudal joint capsule of a shoulder with multiple chronic soft tissue injuries. Caudal is to the right with dorsal up, the telescope is looking caudomedially from a lateral portal, and the joint capsule fills the entire image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.197  A well-defined ridge of joint capsule fibrosis in the caudal joint compartment surrounded by diffuse fibrosis in a shoulder with multiple soft tissue injuries. Dorsal is up and caudal is to the right with the telescope looking caudomedially from a lateral portal. The caudal surface of the humeral head is to the left with joint capsule to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

healing, and worsened results. Use of standard tips requires great care to prevent excessive tissue damage. Application of the standard tips is done with a foot switch taping technique which provides very short energy bursts to control the progression and extent of thermal modification. The intent of these techniques is to debride the damaged tissue and tighten loose tissue without over treatment. Medial glenohumeral ligament lesions (Figures 3.203 and 3.204) and subscapularis tendon injuries (Figure  3.205) have been treated successfully with this technique. During the time that this approach was used for treatment of tendon and ligament injuries of the

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.198  A defined oblique ridge of joint capsule fibrosis surrounded with villus synovial ghosts. A small portion of humeral head is to he lower left with joint capsule filling the remainder of the image. The telescope is looking caudomedially from a lateral portal with dorsal up and caudal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.199  Caudal joint capsule distortion with irregular bands of fibrosis. Dorsal is up with caudal to the right, the telescope is looking caudomedially from a lateral portal, and joint capsule fills the entire image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

shoulder joint, good results were achieved with proper case selection and most importantly proper postoperative care. Thermally modified tissues are weaker immediately after treatment than before treatment with recovery to pretreatment strength levels and more importantly to preinjury strength levels requiring approximately 90 days. Overactivity during this healing phase can cause further tissue damage with greater joint instability and poor results. A padded spica bandage derived from the “Robert Jones splint” concept was used for postoperative support for a period of two to four months depending on the patient and the extend of injury. When postoperative

Figure 3.200  A medial glenohumeral ligament injury amenable to thermal modification. The ligament is seen running obliquely across the image from upper left to lower right with the upper portion intact and the lower portion damaged. The injured portion of the ligament is delineated by frayed tissue, bowing of the ventral margin, and linear fiber separation seen as a dark area in the center of the injury. The glenoid articular surface is to the upper right with humeral head at the bottom. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. There is an area of increased blood vessels along the ligament margin adjacent to the glenoid. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.201  A 3.5 mm thermocouple handpiece tip attached to the VAPR radiofrequency unit being used for thermal modification of the medial glenohumeral ligament from the previous figure. The instrument is inserted through a caudolateral portal and is placed against the injured medial joint tissue. Dorsal is up with the glenoid filling the top of the image and medial soft tissues across the bottom with injured tissue obscured by the instrument. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

patient and splint care were followed conscientiously, results were consistently good and when care was not appropriate results were consistently poor. When thermal modification was performed at the time of diagnostic arthroscopy, the time and materials required for completion of this technique are minimal.

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Figure 3.202  A standard 2.3 mm wedge effect handpiece tip for the VAPR radiofrequency unit being applied to an injured subscapularis tendon for thermal modification. Dorsal is up, cranial is to the right, the telescope is looking medially from a lateral portal, and the instrument is inserted through a craniolateral portal. Medial glenohumeral ligament fills the upper left of the image with a small portion of humeral head to the lower right below the instrument, and injured subscapularis tendon is the wedge of tissue behind the instrument tip that is obscured by frayed tissue and villus reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.203  The thermocouple VAPR handpiece inserted through a craniomedial portal with the tip being applied to the medial glenohumeral ligament injury seen in Figure 3.200. Telescope position, orientation, and visible structures are unchanged. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Current recommendations for these injuries are now focused on stem cell therapy with intra‐articular, intra‐ lesion, and intravenous stem cell injections (Canapp et al. 2016). Post‐treatment care is still a critical factor using a shoulder support harness, activity restriction, anti‐inflammatory drugs, and physical therapy. This treatment approach has achieved good results with return to pain‐free full activity in a high percentage of cases. Second look arthroscopy has confirmed complete healing of tendon and ligament injuries with reduction

Figure 3.204  Completion of thermal modification of the medial glenohumeral ligament injury seen in Figures 3.200 and 3.203. Note that the damaged portion of the ligament has been modified but the intact portion has been left untreated. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.205  Completion of thermal modification of the subscapularis tendon injury seen in Figure 3.171. The surface injuries of the tendon have been debrided leaving the structurally intact portion of the tendon untreated. Dorsal is up with cranial to the right, the telescope is looking medially from a lateral portal, and the instrument is inserted through a craniolateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

or elimination of other intra‐articular changes. Many unanswered questions still remain on specifying optimum treatment for these injuries. Conservative management is typically employed for economic reasons or when arthroscopy has not been performed and a definitive diagnosis has not been established. In these cases, a shoulder support harness, activity restriction, and anti‐inflammatory drugs are currently recommended for conservative management. Results in a large number of cases have not been determined, but success has been seen in some situations. Long‐term use of a shoulder support harness may be indicated if complete resolution is not achieved. Postoperative care is critical to achieve optimal results with any of the above treatments. Joint movement and

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.206  A lateral shoulder radiograph of a 5 month old Irish Wolfhound dog with a normal separate caudal glenoid ossification center. Later radiographs determined that the ossification center fused normally with the scapula. Source: Courtesy Dr. Gary Brown.

Figure 3.207  A lateral shoulder radiograph of a young large breed dog with front leg lameness and shoulder pain. The mineralized density caudal to the caudal margin of the glenoid is a UCGOC fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

stress must be limited and controlled during the recovery period. Maintaining adequate activity restriction and limitation of joint movement for this period is difficult for the patient and the client limiting its effective application in practice. The shoulder harness support system has greatly improved implementation and successful results.

3.5.4  Ununited Caudal Glenoid Ossification Center (UCGOC) Failure of the separate caudal glenoid rim ossification center to fuse with the glenoid can cause lameness and shoulder pain. This diagnosis is usually made in young large breed dogs with front leg lameness of var-

Figure 3.208  A lateral shoulder radiograph in a young large breed dog with front leg lameness and shoulder pain with no visible free UCGOC fragment but with an indistinct margin of the caudal glenoid. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

iable duration and severity, and with or without nonspecific shoulder pain (Beale et al. 2003; Kunkel and Rochat 2008a; Olivieri et al. 2004). UCGOC has been reported in a cat (Serck and Wouters  2019). Lateral radiographs of the shoulder joint in young large breed dogs reveal a normal separate mineralized center on the caudal margin of the glenoid (Figure 3.206). When this ossification center does not fuse with the glenoid during normal growth, it can become a loose or ununited caudal glenoid ossification center fragment (Figure  3.207). Occasionally, the lesion is not well defined and appears only as a loss of clear detail at the caudal margin of the glenoid (Figure  3.208). Caudal glenoid radiographic bone densities are also seen in older dogs in otherwise normal joints (Figure 3.209a) or sometimes associated with generalized degenerative changes of the shoulder joint (Figure  3.209b). It has not been fully established if these densities are a chronic ununited ossification center, a ridge of osteophytes secondary to a degenerative process that has fractured off the bone, or damaged joint capsule tissue that has mineralized. The radiographic finding of a separate caudal glenoid mineralized density in a patient with lameness and shoulder pain is an indication for arthroscopy regardless of possible unclear etiology. Arthroscopy of the shoulder joint for UCGOC uses a lateral telescope portal and a caudal operative portal with the same placement and technique as for OCD of the shoulder (Figure 3.3). Complete exploration of the

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(a)

(b)

Figure 3.209  (a) A lateral shoulder radiograph in an old dog with a free mineral density caudal to the caudal margin of the glenoid. (b) A lateral shoulder radiograph in an old dog with generalized degenerative changes, a large osteophyte off the caudal humeral head, and a free mineral density caudal to the caudal margin of the glenoid. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.210  A small well-defined movable ununited glenoid ossification center fragment in a young dog with front leg lameness and shoulder pain. The fragment is seen as a raised with whiter cartilage area in the caudal margin of the glenoid. Dorsal is up, caudal is to the left, and the telescope is looking caudomedially from a lateral portal. The humeral head is to the lower right, the glenoid is to the upper right and villus ghosts coming off the caudal joint capsule are seen to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

joint is conducted to look for other pathology or an etiology for osteophyte formation, especially in older dogs. Any additional pathology is also defined and addressed. UCGOC in young dogs appear as variable‐ sized nondisplaced movable fragment (Figure 3.210),

Figure 3.211  A medium size, long thin, indistinct movable ridge of bone with whiter cartilage representing an ununited glenoid ossification center fragment in a young dog with front leg lameness and shoulder pain. The telescope is looking caudomedially from a lateral portal with dorsal up and caudal to the left. The glenoid fills the upper image with the humeral head across the bottom and a 20-gauge needle is positioned to establish a caudolateral operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

ridges of bone on the caudal margin of the glenoid (Figure  3.211) or as displaced caudal glenoid bone fragments (Figure  3.212). Occasionally, an area of moth‐eaten cartilage is seen on the caudal margin of the glenoid that could represent minimal presentation of an UCGOC (Figure  3.213) or is an unrelated

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.212  A large, displaced movable ununited caudal glenoid ossification center fragment in a young dog with front leg lameness and shoulder pain. The glenoid is seen as the white smooth cartilage surface extending into the top of the image with a very small portion of humeral head to the lower right. The movable bone fragments are seen between areas of frayed tissue at the center and lower left. The telescope is looking caudomedially from a lateral portal and dorsal is up with caudal to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.213  A moth-eaten rim of cartilage on the caudal margin of the glenoid that could represent minimal presentation of UCGOC. The glenoid fills the right side of the image projecting to the left with irregular cartilage along its caudal margin. Dorsal is up and caudal is to the left with the telescope looking caudomedially from a lateral portal. A 20-gauge needle is seen to the lower left and was placed to establish a caudolateral operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

pathology. In older dogs, variable‐sized movable fragments (Figures  3.214 and  3.215) and ridges (Figure 3.216) of bone occur on the caudal margin of the glenoid. Clinically significant caudal glenoid mineralized densities are unstable and palpation with a hemostat or probe (Figure  3.217) may be needed to

Figure 3.214  A small free UCGOC fragment in the shoulder of an older dog with soft tissue injury adjacent to the fragment. Glenoid articular surface fills the upper portion of the image with the fragment is in the center of the image and it is seen projecting below the caudomedial margin of the glenoid. The injured soft tissue is the frayed material to the right of the bone fragment. The humeral head fills the lower left of the picture. Dorsal is up with caudal to the right and the telescope is looking caudomedially from a lateral portal. Chondromalacia is present on the visible humeral head cartilage and on the glenoid articular surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.215  A very large free UCGOC fragment in the shoulder of an older dog with full thickness cartilage loss from the opposing humeral articular surface and from an adjacent area of glenoid articular surface. The loose bone fragment is to the upper right with the caudal glenoid to the upper left and humeral head is seen across the bottom of the image. Caudal is to the right and dorsal is up with the telescope looking caudomedially from a lateral portal. The Grade V chondromalacia on the humeral head is seen as the irregular pale pink area extending across the top of the exposed humeral head and there is only a small area of exposed glenoid bone to the extreme upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 3.216  A large ridge of bone on the caudal margin of the glenoid in an older dog with front leg lameness and shoulder pain. Caudal is to the right with dorsal up and the telescope is looking caudomedially from a lateral portal. A small portion of the caudal margin of the glenoid is seen to the upper left with a smooth surface, a subtle demarcation line is visible at the transition from smooth cartilage to the roughened surface of the abnormal bone, and the humeral head is to the lower left with Grade II chondromalacia on the center of its exposed surface. The bone ridge appears fixed, but palpation determined that is movable. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.217  A hook probe was placed caudal to a suspected UCGOC fragment to confirm that the fragment is unstable. The probe was inserted through a caudolateral portal with the telescope looking caudomedially from a lateral portal. Dorsal is up and caudal is to the left. The glenoid articular surface is at the top, the displaced fragment in the center, a small portion of humeral head to the lower right, and joint capsule is seen in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

determine whether the fragment is movable (Videos 3.8 and  3.9), although some are obvious free fragments (Figures 3.210, 3.212, and 3.215). The free fragment or ridge of bone is removed with hand instruments (Figures 3.218 and 3.219), with the power

Figure 3.218  Removing a small UCGOC fragment, similar to the one seen in Figure 3.210, from the shoulder of a young dog with front leg lameness and shoulder pain. A 3.5 mm Blakesley arthroscopic rongeur was placed through a caudolateral portal with the jaws grasping the lateral end of the fragment. The glenoid fills the top of the image, a small portion of humeral head is to the lower right, and abnormal tissue is seen along the medial margin of the glenoid to the upper right of the loose bone fragment. Dorsal is up, caudal is to the left, and the telescope is looking caudomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.219  Removing a medium sized UCGOC fragment with a 3.5 mm Blakesley arthroscopic rongeur that allowed the entire fragment to be grasped and extracted with one bite of the rongeur. Dorsal is up, caudal is to the left, the instrument is inserted through a caudolateral portal, and the telescope is looking caudomedially from a lateral portal. Humeral head is to the lower right, glenoid is at the top with a rim of abnormal cartilage along its margin, and the fragment is in the center in the jaws of the instrument. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

shaver using an aggressive cutting blade (Figure 3.220) or a burr (Figure  3.221), or with a combination of hand and power instruments. All loose bone is removed (Figure 3.222). If there is any question about

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.220  Removing a moderate size UCGOC fragment with a power shaver using a 3.5 mm full radius aggressive cutting blade. Many of the UCGOC fragments are soft enough to allow use of this type of blade that is designed for cartilage removal. The shaver has been inserted through a caudolateral portal, the telescope is looking caudomedially from a lateral portal, dorsal is up and caudal is to the left. Most of the fragment has been removed with residual debris along the caudal margin of the glenoid defect and normal fixed glenoid is seen across the top of the image. A small portion of humeral head is seen across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.221  Removing a very large UCGOC fragment with a power shaver using a 3.5 mm round burr blade. Fragments of this size can either be removed completely with the shaver or reduced in size with the shaver and the remaining small fragment(s) removed with hand instruments. The fragment fills the majority of the image and no other definable structures are visible. The shaver is inserted through a caudolateral portal, dorsal is up, caudal is to the left, and the telescope is looking caudomedially from a lateral portal. The exposed bone to the right of the shaver burr is the fragment, the frayed tissue across the lower right is cartilage shredded by the shaver, and the frayed tissue across the top is injured tissue at the junction of the glenoid and fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.222  Completed removal of a medium sized UCGOC fragment with no residual free bone fragments. The humeral head is filling the bottom of the image with glenoid across the top and joint capsule across the middle with mild fraying secondary to fragment removal. A small feather of cartilage is projecting from the humeral head that is iatrogenic. Dorsal is up, caudal is to the left, and the telescope is looking caudomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.223  Exploration of an UCGOC fragment resection site using the hook probe to confirm that there are no residual bone fragments. The probe is inserted through a caudolateral portal, the telescope is looking caudomedially from a lateral portal, dorsal is up, and caudal is to the right. The frayed tissue above the probe is due to manipulation for fragment removal. Glenoid is above this frayed tissue and humeral head is at the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

complete removal of all bone fragments, the resection site is explored with the hook probe (Figure 3.223). At completion of the procedure, the joint is irrigated with saline and closure is with individual skin sutures at the portal sites.

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3.5.5  Ununited Supraglenoid Tubercle (USGT) The ossification center of the supraglenoid tubercle can fail to fuse with the body of the scapula resulting in loose intra‐articular bone fragments within the origin of the bicipital tendon (Figure 3.224). Arthroscopic assessment of the bicipital tendon and fragments is used to determine the extent of involvement, if the fragments need to be removed or stabilized, and if bicipital tendon transection is indicated. Single (Figure 3.225) or multiple (Figure  3.226) bone fragments are seen with this abnormality, and the fragments are freely movable with limited soft tissue attachments (Figure 3.227). Removal of the free fragments is most easily performed with hand instruments (Figure 3.228). A significant bicipital tendon defect is usually present following removal of USGT fragments (Figure 3.229), and transection of the bicipital tendon is required to eliminate joint pain. A lateral telescope portal and craniolateral operative portal are used to address this condition (Figure 3.3). Portal closure is with single interrupted 3‐0 Nylon skin sutures.

Figure 3.225  A single loose USGT fragment in the origin of the bicipital tendon. Supraglenoid tubercle is to the upper left, bicipital tendon is in the background of the lower right, and the loose fragment is in the center of the image. Dorsal is up, medial is to the left, and the telescope is looking cranially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5.6  Arthroscopic-Assisted Intra-Articular Fracture Repair Anatomic reconstruction of fractures involving the articular surfaces can be facilitated with arthroscopy either through typical portals in the closed joint or with

Figure 3.226  Manipulation of the USGT fragment seen in Figure 3.224 revealed that there were multiple loose fragments in the origin of the bicipital tendon. Telescope position, orientation, and visible structures are the same as in Figure 3.224 except that the visible bone fragment has been displaced laterally revealing a second fragment to the left under the origin of the medial glenohumeral ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.224  An ununited supraglenoid tubercle bone fragment seen as a smooth white oval projection caudally from the origin of the bicipital tendon at the right side of the image. The telescope is looking cranially from a lateral portal with dorsal up and lateral is to the right. Supraglenoid tubercle is at the top of the image, humeral head is across the bottom, the cranial tip of the medial glenohumeral ligament is to the left, and bicipital tendon is to the right below the bone fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

an open joint in dogs and cats (Beale and Cole  2012; Cole and Beale 2019). The telescope is placed into the joint space, irrigation is employed to establish a clear field, the fracture line is visualized (Figure 3.230), and articular cartilage damage is assessed (Figure  3.231). Small intra‐articular chip fracture fragments are identified and removed with arthroscopy as part of an open fracture reconstruction or when they occur as individual lesions. Gunshot fracture management is aided with

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.227  Further displacement of the fragment seen in Figures 3.224 and 3.226 was produced by manipulation of the joint. An instrument was not needed to determine that the fragments were movable. There was limited attachment of this fragment to the periphery of the bicipital tendon. The second fragment to the left is more clearly demonstrated in this figure than in the previous two images. The telescope is inserted further in this image, but its position is otherwise unchanged with orientation the same. The supraglenoid tubercle is at the top of the image with the large fragment to the lower right and the second fragment to the far left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.228  Removal of the USGT fragment seen in Figure 3.225 with 3.5 mm Blakesley rongeurs. The instrument is inserted through a craniolateral portal with telescope position, orientation, and visible structures unchanged from Figure 3.225. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

arthroscopy for debridement of the injury and removal of bullet fragments (Figure  3.232). Following fracture reduction, the adequacy of alignment is evaluated with the arthroscope (Figure 3.233). Implant position is also evaluated with arthroscopy (Figure  3.234) allowing adjustment, while the fracture site is still exposed.

Figure 3.229  The bicipital tendon defect following removal of the bone fragment seen in Figure 3.225 and 3.228. Telescope position, orientation, and visible structures are the same as the previous images. A VAPR probe is inserted through the craniolateral portal and has been positioned to transect the remaining portion of the bicipital tendon. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.230  A glenoid fracture visualized with arthroscopy prior to reduction. Irrigation was used to clear the joint of free blood and blood clots to create a clear visual field. The telescope is looking medially from a lateral portal with dorsal up on the image. Undamaged glenoid articular cartilage is seen in the bottom of the image with the fracture surface to the upper right, a small sliver of the opposing fracture fragment is seen to the far upper left, and the fracture gap is at an oblique angle across the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5.7  Arthroscopic Biopsy of Intra-Articular Neoplasia Intra‐articular neoplastic masses can be found with arthroscopy during shoulder exploration in cases of lameness and shoulder pain that do not have radiographic changes (Figure 3.235). Arthroscopy can also be employed to obtain biopsies of epiphyseal bone lesions

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Figure 3.231  Full thickness cartilage damage, Grade V chondromalacia, on the humeral head caused by a displaced bone fragment in a shoulder fracture. Dorsal is up and cranial is to the left with the telescope looking caudomedially from a lateral portal. The humeral head is to the left with normal cartilage to the far left and exposed eburnated bone seen as a tan colored stripe running from the top to the bottom of the image. A large free bone fragment is to the upper right and hyperemic joint capsule is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.232  Removal of a bullet fragment from an intra-articular gunshot fracture of the shoulder. The bullet fragment is not clearly visible because it is surrounded by blood clot and fibrin. A 3.5 mm rongeur, seen on the left side of the image, was used to remove the fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

seen on radiographs and, in many cases, will be the least traumatic approach for obtaining biopsies.

3.5.8  Glenoid Cartilage Defects Defects in glenoid articular cartilage are seen unrelated to other identifiable causative pathology. Chondromalacia of glenoid cartilage secondary to

Figure 3.233  Glenoid fracture reduction accuracy determined with arthroscopy. The apparent size of the gap between the bones is greatly magnified with the telescope and in reality, is less than one millimeter. The level of the two joint surfaces, a more critical factor in articular fracture reduction, is anatomic in its alignment. Dorsal is up and the telescope is looking medially from a lateral portal. Humeral head fills the bottom of the figure with glenoid across the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.234  An exposed screw tip protruding from the caudal margin of the glenoid following fixation of the fracture seen in Figures 3.230 and 3.233. The screw was removed and replaced with a shorter screw. The humeral head is seen to the lower left with a small portion of glenoid at the top and joint capsule to the lower right. Dorsal is up and caudal is to the right with the telescope looking caudomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

OCD (Figures 3.83–3.85) was discussed, but the cartilage changes presented with this abnormality do not have a visible primary etiology. The appearance of these lesions separates into two different categories,

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.235  An intra-articular neoplastic lesion identified with arthroscopy in a patient with a front leg lameness, shoulder pain, and no radiographic changes. The lesion was biopsied using arthroscopy. Ongoing bleeding into the joint prevented a clear image for capture but the visual field was more than adequate for identification and biopsy. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.236  A very small full thickness glenoid cartilage defect, Grade IV chondromalacia, with the appearance of a wear lesion due to the thin cartilage margins of the lesion. There were no findings with arthroscopy to indicate an etiology. Dorsal is up and the telescope is looking medially from a lateral portal. The glenoid fills the top of the image, a small portion of humeral head is at the bottom, and the cartilage defect is the central darker area. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

wear‐like lesions and those that seem to be cartilage formation defects. Wear‐like lesions are typically full thickness and range from very small (Figure 3.236) to moderate (Figure  3.237) in size. Partial‐thickness

Figure 3.237  A moderate size full thickness glenoid cartilage defect in the center of the glenoid articular surface, Grade IV chondromalacia, with the appearance of a wear lesion due to its thin tapered margin. The glenoid fills the top of the picture and humeral head is seen at the bottom. Dorsal is up with caudal to the lift and the telescope looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.238  A moderate size partial thickness glenoid cartilage defect, Grade III chondromalacia, with the appearance of a wear lesion seen in the center of the glenoid. Dorsal is up and the telescope is looking medially from a lateral portal. The glenoid fills the top of the image with humeral head at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

wear‐like lesions are also seen (Figure 3.238). Cartilage formation defects also have a wide range in size, depth, and appearance. Small well‐defined fissures (Figure  3.239), diffuse superficial lesions (Figure 3.241), diffuse deeper lesions (Figure 3.241), full‐thickness lesions with exposed bone (Figure3.242), and extensive irregular bilateral lesions (Figures  3.243 and 3.244) are seen.

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Figure 3.239  A cartilage lesion seen in the center of the glenoid articular surface as a well-defined cleft or fissure line that could be Grade II or Grade III chondromalacia depending on the depth of the lesion. This appears more like a formation defect rather than a wear lesion and nothing was seen arthroscopically to indicate etiology. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.240  A irregular diffuse superficial area of cartilage depression, Grade II chondromalacia, that appears like a cartilage formation defect rather than cartilage wear. The glenoid almost fills the entire lesion with a small area of humeral head at the lower left. Dorsal is up and the telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.241  An irregular deeper cartilage formation defect, Grade III chondromalacia, seen in the center of the glenoid articular surface. Dorsal is up and the glenoid fills the entire image. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.242  A full thickness cartilage formation defect with exposed bone in the center of the glenoid with no apparent etiology. Dorsal is up with the glenoid filling the upper figure, humeral head is at the bottom, and the telescope is looking medially from a lateral portal. This is Grade IV chondromalacia because there is visible bone in areas of the lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

3.5.9  Chondromalacia Most cases of chondromalacia in the shoulder of dogs are secondary to identifiable causative pathology. One form where an etiology has not been defined is the previously described glenoid cartilage defects. Mild chondromalacia of undetermined cause is also seen (Figure 3.245).

3.5.10  Infraspinatus Muscle Contracture The infraspinatus muscle and tendon are not considered to be intra‐articular structures, and arthroscopy is not generally considered as an indicated approach for this disease. Examination of the shoulder joint using arthroscopy is potentially indicated to define

3.5  ­Diseases of the Shoulder Diagnosed and Managed with Arthroscop

Figure 3.243  An extensive cartilage formation defect in the right shoulder of a dog with bilateral lesions, this is Grade III chondromalacia. The telescope is looking medially from a lateral portal with dorsal up and the glenoid fills almost all the image with a small portion of humeral head at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.245  Grade I chondromalacia seen as blisters in the cartilage on the cranial portion of the humeral head. The etiology of these blisters is not known but there was possible exposure to Enrofloxacin during growth. Dorsal is up with humeral head articular cartilage filling the bottom of the image with villus synovial reaction indistinctly visible in the upper background. The telescope is looking craniomedially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.244  An extensive cartilage formation defect in the left shoulder of the dog seen in the previous image. There were bilateral lesions, but they were distinctly different as seen by comparing the two figures. The glenoid fills the entire picture with dorsal up. The telescope is looking medially from a lateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 3.246  Villus synovial reaction covering the subscapularis tendon in the shoulder joint of a dog with infraspinatus muscle contracture. The telescope is looking medially from a lateral portal with dorsal up. The cranial arm of the medial glenohumeral ligament is to the upper right with humeral head to the lower left. Subscapularis tendon can be indistinctly seen behind the reactive synovium. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

additional pathology (Figure  3.246) associated with infraspinatus muscle fibrosis. The myotendinous junction of infraspinatus muscle is at, or close to, the level of the joint and, when there is muscle fibrosis, this structure is visible arthroscopically as a linear

indentation in the caudolateral area of the joint (Figure 3.247). With the visibility of the fibrotic band in the joint using arthroscopy, it seems reasonable that the transection of this structure would be possible under arthroscopic guidance.

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Figure 3.247  The fibrotic band of the infraspinatus muscle visible in the caudolateral area of the shoulder joint in a dog with infraspinatus muscle contracture. The telescope is looking caudally from a lateral portal with the angle of the visual field directed laterally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­References Bardet, JF. (1998) Diagnosis of shoulder instability in dogs and cats: a retrospective study. J. Am. Anim. Hosp. Assoc. 34, 42–54. Beale, BS. & Cole, G. (2012) Minimally invasive osteosynthesis technique for articular fractures. Vet. Clin. North Am. Small Anim. Pract. 42, 1051–68. Beale, B. & Hulse, D. et al. (2003) Incomplete fusion of the caudal glenoid ossification center. In: Small Animal Arthroscopy (ed. B. Beale, D. Hulse et al.). pp. 46–7. Saunders Elsevier, Philadelphia, PA. Bergenhuyzen, AL. & Vermote, KA. (2010). Long‐term follow‐up after arthroscopic tenotomy for partial rupture of the biceps brachii tendon. Vet. Comp. Orthop. Traumatol. 23, 51–5. Bilmont, A. & Mathon, D. et al. (2018) Arthroscopic management of Osteochondrosis of the glenoid cavity in a dog. J. Am. Anim. Hosp. Assoc. 54, e545‐03. van Bree, H. & Degryse, H. et al. (1993) Pathologic correlations with magnetic resonance images of osteochondrosis lesions in canine shoulders. J. Am. Vet. Med. Assoc. 202, 1099–105. Bruggeman, M. & Van Vynckt, D. et al. (2010) Osteochondritis dissecans of the humeral head in two small‐breed dogs. Vet. Rec. 166, 139–41. Canapp, SO Jr. & Canapp, DA. et al. (2016) The use of adipose‐derived progenitor cells and platelet‐rich plasma combination for the treatment of supraspinatus tendinopathy in 55 dogs: a retrospective study. Front. Vet. Sci. 3, 61.

Cole, G. & Beale, B. (2019) Minimally invasive Osteosynthesis techniques for articular fractures. Vet. Clin. North Am. Small Anim. Pract.: pii S0195‐5616(19), 30126–3. Cook, JL. & Kenter, K. (2005) Arthroscopic biceps tenodesis: technique and results in six dogs. J. Am. Anim. Hosp. Assoc. 41, 121–7. Devitt, CM. & Neely, MR. (2007) Relationship of physical examination test of shoulder instability to arthroscopic findings in dogs. Vet. Surg. 36, 661–8. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Innes, JF. & Brown, G. (2004) Rupture of the biceps brachii tendon sheath in two dogs. J. Small Anim. Pract. 45, 25–8. Jones, SC. & Howard. J (2019) Measurement of shoulder abduction angles in dogs: an ex vivo study of accuracy and repeatability. Vet. Comp. Orthop. Traumatol. 32, 427–32. Kunkel, KA. & Rochat, MC. (2008a) A review of lameness attributable to the shoulder in the dog: part one. J. Am. Anim. Hosp. Assoc. 44, 156–62 Kunkel, KA. & Rochat, MC. (2008b) A review of lameness attributable to the shoulder in the dog: part two. J. Am. Anim. Hosp. Assoc.44, 163–70. Lafuente, MP. & Fransson, BA. (2009) Surgical treatment of mineralized and nonmineralized supraspinatus tendinopathy in twenty‐four dogs. Vet. Surg. 38, 380–7. Mitchell, RA. & Innes, JF. (2000) Lateral glenohumeral ligament rupture in three dogs. J. Small Anim. Pract. 41, 511–4.

  ­Reference

Olivieri, M. & Piras, A. et al. (2004) Accessory caudal glenoid ossification centre as possible cause of lameness in nine dogs. Vet. Comp. Orthop. Traumatol. 17, 131–5. Olivieri, M. & Ciliberto, E. et al. (2007) Arthroscopic treatment of osteochondritis dissecans of the shoulder in 126 dogs. Vet. Comp. Orthop. Traumatol. 20, 65–9 Penelas, A. & Gutbrod, A. et al. (2018a) Feasibility and safety of arthroscopic medial glenohumeral ligament and subscapularis tendon repair with knotless anchors: a cadaveric study in dogs. Vet. Surg. 47, 817–26. Penelas, A. & Pozzi, A. et al. (2018b) [Arthroscopic‐assisted stabilization of medial shoulder instability in a miniature poodle]. Schweiz. Arch. Tierheilkd. 160, 533–8. Person, MW. (1986) Arthroscopy of the canine shoulder joint. Comp. Cont. Ed. 8, 537–48. Person, MW. (1989) Arthroscopic treatment of osteochondritis dissecans in the canine shoulder. Vet. Surg. 18, 175–89. Pettitt, RA. & Innes, JF. (2008) Arthroscopic management of a lateral glenohumeral ligament rupture in two dogs. Vet. Comp. Orthop. Traumatol. 21, 302–6. Pettitt, RA. & Clements, DN. et al. (2007) Stabilization of medial shoulder instability by imbrication of the

subscapularis muscle tendon of insertion. J. Small Anim. Pract. 48, 626–31. Ridge, PA. & Cook, JL. et al. (2014) Arthroscopically assisted treatment of injury to the lateral glenohumeral ligament in dogs. Vet. Surg. 43, 558–62. Serck, BM. & Wouters. EE. (2019) Ununited accessory caudal glenoid ossification centre and associated joint mouse as a cause of lameness in a cat. JFMS Open Rep. 5, 2055116919879255. Vandevelde, B. & Van Ryssen, B. et al. (2006) Comparison of the ultrasonographic appearance of osteochondrosis lesions in the canine shoulder with radiography, arthrography, and arthroscopy. Vet. Radiol. Ultrasound 47, 174–84. Wall, CR. & Taylor, R. (2002) Arthroscopic biceps brachii tenotomy as a treatment for canine bicipital tenosynovitis. J. Am. Anim. Hosp. Assoc. 38, 169–75. Wall, CR. & Cook, CR. et al. (2014) Diagnostic sensitivity of radiography, ultrasonography, and magnetic resonance imaging for detecting shoulder osteochondrosis/osteochondritis dissecans in dogs. Vet. Radiol. Ultrasound. 56, 3–11.

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4 Arthroscopy of the Elbow Joint Elbow arthroscopy has been most commonly performed in medium to large breed dogs but has also been reported in small dogs (Hans et al. 2016) and in cats (Staiger and Beale 2005). Elbow joint arthroscopy is indicated when there is front leg lameness with elbow pain, crepitus, joint capsule distension, joint thickening or swelling, reduced range of joint motion, or when there are radiographic changes compatible with medial coronoid process disease (MCPD or FCP), osteochondritis dissecans (OCD), ununited anconeal process (UAP), intra-articular fractures, or any visible degenerative changes. Significant MCPD can be present in the radiographically normal joint so even very subtle radiographic changes compatible with MCPD are a definite indication for arthroscopy. Pain on palpation of the craniomedial aspect of the elbow joint over the medial coronoid process, pain with full flexion of the elbow joint, or pain with internal or external rotation of the antebrachium is strongly suggestive of MCPD. Absence of pain does not rule out the disease. Localized swelling in the craniomedial aspect of the joint over the medial coronoid process can also be helpful in establishing an indication for arthroscopy. Crepitus is not commonly detected with MCPD and is more likely to be found when there is UAP. Joint capsule distension or joint capsule thickening is nonspecific and can be seen with any of the disease conditions that occur in the elbow joint but is a clear indication for arthroscopy. Generalized swelling or thickening of the joint is also nonspecific, is an indication for arthroscopy, and typically is suggestive of severe joint disease, especially if combined with reduced range of joint motion. Joints with reduced range of motion and swelling may require a more aggressive multiport approach to the joint for treatment of the originating pathology and for removal of multiple secondary osteophytes. It is not important to differentiate between MCPD and OCD of the elbow joint before arthroscopy as patient positioning and portal placement are the same

for both conditions. Unless radiographs are normal, CT or MRI is not needed to establish an indication for arthroscopy. CT is recommended before arthroscopy to improve definition of the pathology that is present and is especially important if there is severe joint pathology with multiple large osteophytes. The CT findings are used to help define the location of osteophytes or arthroliths that need to be removed. Information gained from a CT is very beneficial in planning the arthroscopic procedure. When fragmented medial coronoid process first entered our index of suspicion when evaluating front leg lameness with radiographic changes in the elbow open surgical exploration was used as a diagnostic technique. Arthroscopy was first used by the author as a diagnostic technique to avoid open surgery just to make a diagnosis. Arthroscopy has contributed significantly to our knowledge of the multitude of changes seen with elbow dysplasia. With time and experience, arthroscopy became part of our treatment protocol. Arthroscopy has replaced open surgery as the procedure of choice for diagnosis and management of all forms of elbow dysplasia and provides superior results to other options (Barthélémy et  al.  2014; Evans et  al.  2008; GalindoZamora et  al.  2014). Although there is disagreement with this conclusion there is too much variation in results, case selection, experience, small numbers, and evaluation methods to indicate that arthroscopy is not indicated (Burton et al. 2011; Dempsey et al. 2019).

4.1 ­Patient Preparation, Positioning, and Operating Room Setup The patient is typically placed in dorsal recumbency for elbow arthroscopy whether for bilateral or unilateral procedures. For bilateral procedures, the legs are clipped, suspended (Figure 2.2a and b), prepared, and draped to

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

4.2  ­Portal Sites and Portal Placemen

allow free manipulation of the leg and access to all sides of the elbow joint or joints. For unilateral procedures, the contralateral limb is retracted caudally out of the way and is tied to the surgery table. For unilateral MCPD, OCD, UAP, and multiport joint debridement procedures, two monitors are recommended, one at each end of the table (Figure 2.5), or the monitor can be placed across the table from the surgeon with the assistant standing on the cranial side of the surgeon (Figure 2.6). The monitor is placed at the head of the table for bilateral MCPD and OCD procedures with the assistant and surgeon on the same side of the table with the assistant standing on the cranial side of the surgeon between the monitor and the surgeon (Figure 2.4). Arthroscopy for bilateral UAP can be done with one monitor at the foot of the table (Figure 2.3) but is best done with two monitors, one at the head of the table and one at the foot of the table (Figure 2.5). MCPD is commonly associated with UAP and evaluation of the medial coronoid process with appropriate treatment is an important portion of arthroscopic management for UAP. The reported combination of these two pathologies is 16% (Meyer-Lindenberg and Fehr 2006) but the authors’ experience suggests that the incidence of this combination is closer to 100%. An operative procedure in the craniomedial portion of the joint and in the caudal joint compartment are required for UAP management so without two monitors one of the procedures is performed working with the telescope pointing away from the monitor. This dramatically increases the difficulty of the procedure. Alternatives are to move the monitor between the different parts of the procedure or to perform unilateral procedures with the monitor placed across the table from the surgeon. Complete joint debridement with removal of multiple osteophytes through multiple telescope and operative portals are performed as unilateral procedures with the monitor placed across the table, at the head of the table, or preferably with two monitors. Use of two monitors allows the patient to be rolled from side to side and allows access to the medial aspect of the joint, the lateral aspect of the joint and for placement of caudal compartment portals.

4.2 ­Portal Sites and Portal Placement 4.2.1  Telescope Portals (Medial, Craniolateral, Caudomedial, and Caudal) The most common telescope portal for the elbow joint is the medial portal (Figure 4.1) (Jardel et al. 2010; Tatarunas

and Matera 2006; Van Ryssen et al. 1993). This portal is located directly distal or distal and caudal to the tip of the medial epicondyle of the humerus. The difference in this description does not change the portal position but the difference is based on the landmarks used to define portal location. If the shaft of the humerus is used for alignment, the portal is directly distal to the tip of the epicondyle but if the outside contour of the limb is used for alignment the portal is distal and caudal to the tip of the epicondyle. Descriptions of the location of this portal using the outside of the limb commonly use measured distances, like 1–1.5 cm, caudal to the epicondyle but variability in dog size makes this unhelpful. Comparison of palpation with distance based on radiographs of the patient can be used if palpation by itself is not enough to locate the correct site for portal placement. This portal site is located by palpating the tip of the epicondyle then sliding distally, in

Figure 4.1  Portal sites on the medial aspect of the elbow joint. The three portals shown are the medial telescope portal (asterisk), the craniomedial operative portal(square), and the caudomedial egress portal(X). The ulnar nerve is seen as the white band running along the caudal aspect of the humerus and then curving to run distally along the caudal margin of the ulna. The median nerve is the white band running obliquely across the medial surface of the humerus to run parallel to the medial collateral ligament of the elbow. The medial telescope portal is distal to the medial epicondyle of the humerus in a direct line with the axis of the bone represented by the straight line. The craniomedial operative portal is directly over the medial coronoid process, cranial and slightly proximal to the medial telescope portal, and is caudal to the medial collateral ligament. The caudomedial portal is commonly used for an egress portal but is also used for an operative portal for UAP removal. Source: Modified from Freeman (1999). © John Wiley & Sons.

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a­ lignment with the humoral shaft, until the distal (caudal) margin of the superficial digital flexor muscle is palpated. Telescope insertion is facilitated by internal rotation (pronation) and abduction of the antebrachium to open the medial aspect of the joint. In thin dogs, the medial margin of the articular surface of the semilunar notch can be ­palpated as the antebrachium is internally and externally rotated opening and closing the medial aspect of the joint. The ulnar nerve can be palpated on the medial aspect of the elbow joint immediately caudal to the telescope portal site (Figure 4.1). The nerve is palpated before starting portal placement. A 20-gauge 1.5″ hypodermic needle is placed into the joint at the telescope portal site to confirm accurate placement, joint fluid is aspirated, and the joint is distended with sterile saline. The ulnar nerve is palpated again at this point to confirm that the portal is being placed at a safe location. The needle can be removed or left in place, a stab incision is made into the joint with a no. 11 scalpel blade aligned parallel to the muscle fibers, and the telescope cannula is placed into the joint using the blunt obturator. A variation of the medial telescope portal, the caudomedial telescope portal places it caudal to the ulnar nerve (Figure  4.2). The same technique is used except that the location is at the caudal margin of the medial supracondylar ridge. The primary indication for this portal is for removing medial humeral condylar ridge OCD lesions. These lesions are typically directly under

Figure 4.2  The modified medial or caudomedial telescope portal (asterisk) placed caudal rather than cranial to the ulnar nerve. Anatomic structures are the same as seen in Figure 4.1. Source: Modified from Freeman (1999). © John Wiley & Sons.

the normal medial telescope portal making maintaining a visual field difficult. This proximity to the lesion also increases the difficulty for manipulation of instrumentation to remove the fragments and to debride the bed of the lesion. This more caudally placed portal decreases the difficulty of this procedure. The craniolateral telescope portal (Figure 4.3) was the original telescope portal used by the author for the elbow joint but has been replaced by the medial portal and is no longer commonly used. Primary indications for this portal are for access to the elbow joint when the patient is in lateral recumbency with the joint to be examined on the uppermost side, for complete debridement of the elbow joint using multiple portals, for removal of coronoid process fragments that escape into the cranial compartment, and for arthroscopy-assisted lateral humeral condyle fracture repair. This portal is at the intersection of the cranial margin of the radial head and the cranial aspect of the capitulum. The notch produced by this intersection can be palpated before joint capsule distension. When the joint is distended the joint capsule protrudes at this point to make a small bump

Figure 4.3  The craniolateral telescope portal site (asterisk) on the lateral aspect of the elbow joint. This portal is placed at the junction of the cranial margin of the radial head and the cranial surface of the lateral ridge of the humoral condyle. The portal is cranial to the lateral collateral ligament of the elbow joint seen as the band of tissue running from the lateral epicondyle of the humerus across the joint and splitting to insert on both the radius and ulna. The white stripe running cranial to the humerus and elbow joint is the deep branch of the radial nerve. This craniolateral telescope portal is also used as an operative portal for access to the cranial compartment of the joint. Source: Modified from Freeman (1999). © John Wiley & Sons.

4.2  ­Portal Sites and Portal Placemen

and the telescope is inserted through this joint capsule prominence. If there is adequate joint distension due to the disease process, a 20-gauge 1″ hypodermic needle is inserted at the portal site, joint fluid is aspirated, and the joint is distended with saline. A stab incision is made with a no. 11 scalpel blade and the telescope cannula is inserted using the blunt obturator. If there is inadequate joint distension secondary to elbow disease, a 20-gauge 1.5″–2″ hypodermic needle is placed into the caudal joint compartment and the joint is distended with saline to allow portal placement. This portal can be difficult to place because there is a tendency for the blunt obturator of the telescope cannula to slip off the joint capsule and slide across the cranial aspect of the humeral condyle without entering the joint. This can be corrected by extending the stab incision through the joint capsule or using the sharp trocar for joint entry. Structures of the cranial compartment of the joint, including the medial coronoid process, can be evaluated with this portal by passing the telescope medially across the cranial aspect of the humoral condyle (Figure 4.4). A lateral operative portal can be placed directly over the lateral coronoid process of the ulna. The caudolateral portal is commonly used as an egress portal but the same site is used for caudolateral operative or telescope portals. This caudolateral portal is placed caudal to the cau-

dal margin of the supracondylar ridge of the humerus and proximal to the olecranon into the olecranon fossa. Caudal telescope portals are placed into the caudal joint compartment by insertion into the olecranon fossa either medial or lateral to the triceps tendon. These portals allow visualization of the anconeal process and the olecranon fossa. The caudal portal on the lateral side can also provide access to the lateral coronoid process. Primary application of these portals is for removal of anconeal process osteophytes that interfere with joint extension as part of complete multiport joint debridement. The caudal portal on the lateral side can also be used when combined with a lateral operative portal for removal of lateral coronoid process pathology that cannot be accessed using the medial telescope portal. UAP fragment removal is generally performed using the medial telescope portal with a caudal operative portal on the medial side. Medial and lateral caudal portals can also be used for UAP removal and to evaluate the caudal compartment for any residual loose debris after the UAP fragment has been removed. The craniomedial operative portal site can be used as a telescope portal site for visualization of radial head osteophytes, humeral condyle fractures, and MCPD fragments that have escaped into the cranial compartment of the joint. This site is used as a telescope portal site after it has been used as an operative portal site and the transfer can be done with a switching stick or the telescope cannula can be passed through the portal with the blunt obturator. Access to the cranial compartment of the joint through the standard medial telescope portal is facilitated by subtotal coronoidectomy.

4.2.2  Operative Portals (Craniomedial, Lateral, Craniolateral, and Caudal)

Figure 4.4  From the craniolateral telescope portal structures of the cranial compartment can be examined by passing the telescope medially across the cranial aspect of the humoral condyle. Source: Modified from Freeman (1999). © 1999, Elsevier.

The craniomedial operative portal (Figures 4.1 and 4.2) is the most common operative portal for the elbow joint and is used for medial coronoid process disease management and for removal of OCD lesions of the medial humeral condylar ridge. This site is caudal to the medial collateral ligament and is located cranial and slightly proximal to the telescope portal. This site is directly over the medial coronoid process of the ulna providing excellent access and triangulation for fragment removal and coronoid process revision (Figure 4.5). The portal site is located with a 20-gauge 1.0″ or 1.5″ needle, accurate placement is confirmed by visualizing the needle inside the joint with the telescope (Figure 4.6) (Video 2.2), a stab incision is made with a no. 11 scalpel blade parallel to the needle and aligned to pass between, not across, the ­muscle fibers (Figure 4.7), and a curved mosquito hemostat is used to

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Figure 4.5  Instruments passed through the medial telescope portal and the craniomedial operative portal provide excellent access and triangulation for medial coronoid process revision. Source: Modified from Freeman (1999). © 1999, Elsevier.

Figure 4.6  A 20-gauge hypodermic needle seen in the craniomedial joint compartment in preparation for craniomedial operative portal placement. The telescope is looking craniolaterally from the medial portal with dorsal up and medial to the left. The medial ridge of the humeral condyle is seen to the upper left, medial coronoid process fills the bottom of the image, the medial collateral ligament is the vertical band of tissue in the center, a small portion of radial head is to the left, and intraarticular fat covered with mild synovial reaction is to the right. The visible cartilage surfaces are normal and no coronoid process abnormality is present. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

dissect a portal tract into the joint (Figure 4.8) (Video 2.2). Operative cannulas are difficult to maintain at this portal site because of the small joint space and short distance of the bone from the joint capsule.

Figure 4.7  The tip of a no.11 scalpel blade seen in the craniomedial joint compartment, next to a previously placed needle, making a craniomedial operative portal incision. Proximal is up and medial is to the left with the telescope looking craniolaterally from a medial portal. Medial humeral condyle ridge is seen to the upper right, and medial coronoid process with grade III chondromalacia fills the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.8  A curved mosquito hemostat placed through the craniomedial operative portal incision is being used to enlarge the portal and establish a tissue tract. This is the same elbow as the previous figure with the same telescope position and orientation. In addition to the structures described in the previous image a small portion of radial head is seen to the far right and medial collateral ligament is the vertical band in the upper center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Access to the lateral coronoid process of the ulna and lateral ridge of the humeral condyle can be attained by entering the lateral aspect of the joint distal to the epicondyle using landmarks similar the medal telescope portal but on the lateral side. This operative portal can be combined with a craniolateral or caudolateral telescope portal or can also be used with a medial telescope portal for procedures requiring limited manipu-

4.3  ­Nerves of Concern with Elbow Joint Arthroscop

lations. Uses of this portal are for removal of lateral coronoid process pathology and for removal of medial coronoid process fragments or OCD fragments that escape into the lateral joint space. This portal can also be used as a telescope portal. An operative portal can also be established at the craniolateral telescope portal site (Figure 4.3). This operative portal is used for removal of coronoid process fragments that escape into the cranial compartment of the joint and for removal of dorsal radial head osteophytes as part of a multiport elbow debridement procedure. This portal is usually placed from inside the joint using a craniomedial operative portal cannula and a switching stick. Caudal compartment operative portals are placed either medial or lateral to the triceps tendon at the same locations as described for the caudal telescope portals. They are used for debridement of anconeal process osteophytes as part of multiport complete joint debridement combined with a caudal telescope portal. For this application, the operative portal is placed at the caudal portal site not used by the telescope. A caudal operative portal on the medial side is used for removal of UAP fragments combined with a medial telescope portal. The operative portal for UAP removal is more accurately a mini-arthrotomy than a portal because it needs to be large enough for removal of the UAP fragment in one piece.

4.2.3  Egress Portals The most common egress portal sites for the elbow joint are caudal portals on the medial or lateral sides with the egress cannula positioned into the olecranon fossa (Figures 4.1 and 4.2). The craniomedial operative portal site (Figures 4.1 and 4.2) can be used as an egress portal site during caudal joint compartment debridement or during UAP removal. For these procedures, the craniomedial site is used as an operative portal for managing medial coronoid process pathology and is then converted into an egress portal simply by placing an egress cannula into the already established operative portal site. Any of the elbow joint operative portal sites can also be used for outflow either with an egress cannula, with outflow around operative instruments, or through an operative cannula.

4.3 ­Nerves of Concern with Elbow Joint Arthroscopy The ulnar nerve is within millimeters of the medial telescope portal of the elbow joint (Jardel et al. 2010). The ulnar nerve courses along the cranial border of the

medial head of the triceps continuing on the medial aspect of the humerus immediately caudal to the point of the medial epicondyle to cross the medial aspect of the elbow joint. After crossing the elbow joint, the ulnar nerve courses distally on the caudomedial antebrachium between the humeral head of the superficial digital flexor muscle and the ulnar head of the flexor carpi ulnaris muscle (Figure 4.1). The nerve can be palpated as it crosses the medial epicondyle, allowing location of the nerve at the time of portal site selection and placement. Errors made in attempting to enter the elbow joint are to place the portal too far caudally directly over the nerve for the standard telescope portal or to be too far distally and to slide away from the joint on the medial surface of the ulna. The ulnar nerve is at risk when these errors occur. The ulnar nerve is also within millimeters of the modified medial telescope portal of the elbow joint. This portal is placed caudal to the ulnar nerve distal to the epicondyle and caudal to the axis of the humeral shaft using palpation of the ulnar nerve as a landmark (Figure 4.2). The possible errors in placing this portal are reversed from the standard medial telescope portal with placement of this portal too far cranially or too far dorsally increasing the risk of ulnar nerve damage. The median nerve is at risk with placement of the craniomedial operative portal of the elbow joint (Jardel et  al.  2010). The median nerve crosses the medial extent of the flexor surface of the elbow joint, deep to the craniomedial flexor muscles, near the medial collateral ligament (Figure 4.1). This is close to the operative portal, within millimeters, but because the location of this portal is accurately established by intra-articular observation of needle placement little risk is involved. Keeping this portal caudal to the medial collateral ligament, the standard position of the portal, minimizes the chance for damage to this nerve. The craniolateral telescope portal is close to the radial nerve. The deep branch of the radial nerve crosses the flexor surface of the elbow joint, cranial and medial to this portal, and deep to the extensor muscles (Figure 4.3). Correct placement of this portal is into the protrusion of the distended craniolateral joint capsule at the junction of the articular surfaces of the capitulum and the radial head. There is little risk for radial nerve damage when the portal is properly placed at this location in adequate distension of the joint before portal placement or cranial displacement of the insertion site can cause the cannula to slide medially on the cranial surface of the joint capsule. The radial nerve is at risk when this occurs.

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4.4 ­Examination Protocol and Normal Arthroscopic Anatomy When first entering the elbow through the standard medial telescope portal, anatomic structures are identified that allow orientation within the joint. Maintaining the antebrachium in an internally rotated position with the medial aspect of the joint opened is essential for examination of the elbow joint. The medial coronoid process of the ulna, the radial head, the medial ridge of the humoral condyle, and the medial collateral ligament (Figure  4.9) are used for orientation. Other structures that can be used are the articulation between the ulna and the caudal margin of the radial head (Figure 4.10), the concave ridge of the semilunar notch with the convex surface of the humeral condyle, and the anconeal process (Figure  4.11). Once orientation is established, the joint is examined in a systematic manner to insure evaluation of all the important structures of the joint. Starting in the craniomedial portion of the joint with the telescope oriented cranially the medial coronoid process, medial aspect of the radial head, medial collateral ligament, and the medial ridge of the humeral condyle are evaluated (Figure  4.9). The telescope is swept caudolaterally to see the radial head (Figure 4.12) and continuing in this direction the lateral portion of the radial

Figure 4.9  Normal structures in the elbow joint used for orientation from the medial telescope portal with the telescope angled craniolaterally are the medial coronoid process seen filling the bottom of the image, the radial head visible to the right, the convex medial ridge of the humeral condyle across the top, the medial collateral ligament of the elbow seen at the left of the image with identifiable ligamentous bands, and irregular fat covered with mildly increased vascularity in the center of the picture. Proximal, or dorsal, is up in the image and cranial is to the left. Cartilage surfaces in this image are all normal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.10  Normal structures of the elbow joint seen from the craniomedial telescope portal with the telescope directed laterally. The convex surface of the lateral ridge of the humeral condyle fills the upper right half of the image, the concave ridge of the semilunar notch is seen in the lower right of the picture tapering to the cranial margin of the joint surface, the caudal margin of the radial head is visible in the upper left, articulation between the radial head and the radial notch of the ulna is present in the left center, and the base of the lateral coronoid process is visible extending beyond the semilunar notch. Proximal, or dorsal, is up in the picture and cranial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.11  The tip of the anconeal process is seen filling the image and articulating with the caudal trochlear sulcus of the humoral condyle articular surface seen extending from the lower right, up to the upper right, across the top, and to the upper left. The telescope is looking caudally from a medial telescope portal. Dorsal is to the upper right and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

head articulating with the lateral ridge of the humeral condyle (Figure  4.13) and the radial notch of the ulna (Figure 4.14a). With application of additional rotational and abduction force, rotation of the telescope to face the 30° angle of view distally, and deeper insertion of the

Figure 4.12  From the initial position seen in Figure 4.9 the telescope in this picture is angled more laterally to visualize the radial head. The antebrachium has been returned to an unstressed attitude with neutral rotation allowing the radial head to be in a normal position relative to the ulna. The humeral condyle articular surface is seen extending across the top of the picture, the ulnar articular surface at the base of the medial coronoid process fills the bottom foreground of the image, and the articular surface of the radial head is seen in the center background. A small area of villus synovial reaction is seen in the far left of the image in this otherwise normal appearing joint. Dorsal, or proximal is up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.13  With continued movement of the visual field caudally the lateral surface of the radial head is visible across the bottom of this image with the lateral ridge of the humeral condyle at the top of the image, and with a narrow view of the craniolateral joint space in the background. Proximal is up on this image and cranial is to the left with the telescope looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.14  (a) In this image cranial is to the right, dorsal is up, and the telescope is looking laterally from the medial portal. Continuing to move the telescope angle laterally and caudally the lateral portion of the radial head is visible articulating with the lateral ridge of the humeral condyle and the radial notch of the ulna. The medial ridge of the humeral condyle is to the upper left, the radial head is to the upper right, with the ulnar articular surface filling the lower foreground. The articulation between the caudal margin of the radial head and the radial notch of the ulna is seen as a cleft between the two bones curving across the center of the picture. The lateral coronoid process of the ulna is partially visible extending into the lower left of the image. Note that the level of the radial and ulnar articular surfaces are aligned in this normal joint. (b) The lateral coronoid process is exposed in this elbow with application of additional rotational and abduction force, rotation of the 30-degree angle of the telescope view to face distally, and with deeper insertion of the telescope. The lateral coronoid process is seen in the center of the image. Also visible are the caudal margin of the radial head to the right, the lateral ridge of the humeral condyle across the top of the image, and the articulation of the radial head with the ulna to the right of the lateral coronoid process. The lateral joint space and joint capsule are visible beyond the tip of the lateral coronoid process. Cranial is to the right and proximal is up with the telescope looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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telescope, the lateral coronoid process can be seen in most elbows (Figure  4.14b). In this image, the caudal portion of the radial head, articulation of the radial head with lateral coronoid process, and the lateral ridge of the humeral condyle are also seen. There is extensive variation in the normal appearance of the lateral coronoid process from a thin projection with a narrow but welldefined articulation with the humeral condyle (Figure 4.15) to wide and blunt with a large articular surface with the humeral condyle (Figure 4.16) or small and irregular with no articulation with the humeral condyle (Figure 4.17). Continued caudal angulation of the telescope exposes the semilunar notch and lateral ridge of the humeral condyle (Figure 4.18). The central portion of the semilunar notch with the base of the anconeal process and central portion of the articular surface of the trochlea of the humerus are seen when the telescope is pointed more caudally (Figure 4.19). When the telescope is pointed caudally, the anconeal process is seen with the caudal trochlea of the humeral condyle (Figure  4.20). With flexion of the joint, the tip of the anconeal process is visible (Figure 4.21) and in some joints, the telescope can be passed into the caudal compartment of the joint from the medial telescope portal (Figure 4.22). Orientation when using the craniolateral telescope portal uses the cranial or dorsal aspect of the radial

Figure 4.15  A thin lateral coronoid process with a narrow well-defined cartilage surface articulating with the humeral condyle. A small portion of radial head is seen to the far right, the lateral coronoid process is in the center with articulation of the radial head with the radial notch of the ulna seen as the dark curved cleft between the two bones, lateral ridge of the humeral condyle fills the upper image, with the ridge of the semilunar notch across the bottom. There is normal alignment of the two articular surfaces. Proximal is up, cranial is to the right, and the telescope is looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.16  A large lateral coronoid process with a wide articular surface is seen in the center of the image in contact with the lateral ridge of the humeral condyle that fills the upper right of the picture. A small portion of the caudal margin of the radial head is visible in the upper left, with articulation of the two bones seen as a dark line, and the ridge of the semilunar notch is in the foreground running from the left to the lower right of the image. Dorsal is to the upper right and cranial is to the upper left. Again note the alignment of the radial head and ulnar articular surfaces in this normal joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.17  A small irregular lateral coronoid process with no appreciable surface articulating with the humeral condyle. Proximal, or dorsal, is up on this image with cranial to the right and the telescope os looking laterally from a medial portal. The lateral ridge of the humeral condyle fills the upper image with radial head to the right and ulna across the bottom of the image. Without an articular surface on the lateral coronoid process alignment of the radial head and ulna is not appreciated. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

head (Figure  4.23), cranial articular surface of the humeral condyle (Figures  4.23 and  4.24), the cranial tip of the medial coronoid process (Figures  4.24 and 4.25), and attachment of joint capsule to the distal

4.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 4.18  The top of the ridge of the semilunar notch is seen in the foreground at the bottom of this image with the lateral ridge of the humeral condyle filling the top of the picture. A small portion of the caudal margin of the radial head is to the far left with the lateral coronoid process seen in the center background. Dorsal is up and cranial is to the left with the telescope looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.19  The central portion of the semilunar notch is seen at the bottom of this figure with the base of the anconeal process sweeping up to the left and the lateral ridge of the humeral condyle filling the upper right. Proximal is to the upper right, caudal is to the lower left, distal is down, and the telescope is looking caudolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

humerus (Figure  4.26). The cranial compartment of the joint can also be accessed for examination through the medial telescope portal after removal of the medial coronoid process or through a craniomedial operative portal. Access through the medial telescope portal is easier after a subtotal medial coronoidectomy has

Figure 4.20  The caudal end of the semilunar notch is visible with the anconeal process on the left and the caudal extent of the humeral condyle to the right. Proximal is to the right, distal is down, medial is to the upper left, and the telescope is looking caudolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.21  The tip of the anconeal process is seen in the center of the picture with the joint fully flexed. Proximal or dorsal is up with distal down to the left and medial is to the right. The needle tip on the right is in the medial side of the caudal joint compartment. The telescope is looking caudally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

been performed. From the medial telescope portal, the arthroscope is passed through the space lateral to the medial collateral ligament (Figure  4.27). The dorsal aspect of the radial head and the cranial surface of the humeral condyle (Figure  4.28) are used for landmarks.

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Figure 4.22  In some patients the telescope can be extended into the caudal joint compartment of the elbow from the medial telescope portal. The medial margin of the anconeal process is visible on the left side of the image with the lateral articular surface of the medial wall of the olecranon fossa on the upper right transitioning into medial joint capsule in the lower right. Proximal is up and medial is to the right. The tip of a 20-gauge needle is seen penetrating through the medial joint capsule into the caudal joint compartment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.23  Normal structures of the cranial compartment of the elbow seen from the craniolateral telescope portal with the telescope looking medially. Cranial is to the right and dorsal or proximal is up. The dorsal or cranial margin of the radial head is seen at the bottom of the picture with the cranial surface of the humeral condyle filling the top of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

The caudal portals use the tip of the anconeal process and the caudal articular surfaces of the humeral trochlea for orientation (Figures 4.29 and 4.30). From the caudal portals, the soft tissue membrane of the supratrochlear foramen is seen (Figure  4.31). The telescope can be passed through the supratrochlear foramen (Figure 4.32) to visualize the cranial joint space (Figure 4.33).

Figure 4.24  Moving the telescope further medially from the previous figure exposes the articular surface of the radial head across the bottom of the figure with the tip of the medial coronoid process slightly to the left in the background, craniomedial joint capsule in the background on the right, and the cranial surface of the medial ridge of the humeral condyle across the top. Proximal is up and cranial is to the right with the telescope looking medially. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.25  The tip of the medial coronoid process is seen in the left center of the image with the telescope advanced from the position in the previous figure. A small portion of the craniomedial margin of the radial head is visible at the bottom of the picture with the cranial surface of the medial ridge of the humeral condyle filling the top and the craniomedial joint capsule is to the right. Proximal is up with cranial to the right and the telescope is looking medially from a craniolateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Examination of the caudomedial joint space medial to the epiphysis of the humerus is needed to evaluate for injury of the origin of the extensor muscles of the carpus. This area is examined from the medial telescope portal by directing the telescope tip caudally and medially to enter the joint space medial to the bone and deep to the muscles. The reflection of the joint capsule at the

4.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 4.26  The craniomedial joint space seen from the craniolateral telescope portal with the telescope view shifted proximally bringing the dorsal margin of the humeral condylar articular surface into view on the left. The cranial joint capsule is seen coming off the humerus in the upper left, arching over the top of the image, and extending down the right side of the image. There is a mild villus synovial reaction present in this joint seen as strands of tissue floating in the irrigation liquid. Dorsal or proximal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.27  Visual access to the cranial compartment of the joint from the medial telescope portal is through the space lateral to the medial collateral ligament and medial to both the radial head and medial humeral condyle. In some patients the telescope can be inserted through this space into the cranial joint space, but this typically requires removal of the medial coronoid process. The medial margin of the humeral condyle is seen in the upper left of the picture with the radial head in the lower left, the medial coronoid process in the lower right, and the medial collateral ligament on the right. The cranial joint capsule is seen in the central background. Proximal is to the upper left and cranial is to the right with the telescope looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.28  Insertion of the telescope into the cranial joint compartment from the medial telescope portal provides an oblique view of the cranial joint. The dorsal margin of the radial head is visible at the bottom of the picture, the cranial joint surface of the humeral condyle is in the upper left, and the joint capsule is seen from the right side of the image across the center to the left extent. There is mild villus reaction in the lower part of the joint capsule. Dorsal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.29  The caudal surface of the tip of the anconeal process at the bottom and the caudal articular surface of the humeral trochlea across the top are visualized looking cranially from a caudal telescope portal. The slight vascular pattern along the margin of the anconeal process is secondary to mild joint disease. Dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­ roximal extent of the joint space with the tendon origin p of the flexor muscles (Figure 4.34) and continuation of the tendon across the caudal margin of the supratrochlear ridge (Figure 4.35) are seen in this joint space. The pars nudosa is a normal area without articular cartilage on the ulnar articular surface. This cartilage

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Figure 4.30  The tip of the anconeal process is projecting across the middle of the picture with its tip on the right seen from an oblique angle through a caudal telescope portal. The soft tissue membrane of the supratrochlear foramen is seen on the right above the tip of the anconeal process. This membrane can be complete or incomplete as is seen in this view with an opening into the cranial joint. Proximal or dorsal is up and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.31  Normal fat in the caudal joint compartment on the caudal surface of a complete soft tissue membrane across the supratrochlear foramen. The telescope is looking cranially from a caudal portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

defect has a wide range of appearance and size including small shallow areas containing fat (Figure 4.36), deeper areas lined with periosteum (Figure  4.37), and large irregular areas (Figure 4.38). The ligament of the radial head extends from its attachment on the base of the medial surface of the

Figure 4.32  The supratrochlear foramen visualized with the telescope looking cranially from a caudal portal. The soft tissue membrane of the supratrochlear foramen was complete but has been penetrated with the telescope to create an opening and providing access to the cranial compartment of the joint. Proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.33  The dorsal or proximal margin of the cranial surface of the humeral condyle as seen with the telescope passed through the perforation in the supratrochlear foramen membrane seen in the previous figure. The humeral condyle articular cartilage margin is visible in the bottom center of the picture with a white ridge of joint capsule coursing from the lower right up over the top of the image. Distended joint capsule is also seen in the background to the left of the articular cartilage and ridge of joint capsule. Cranial is to the left with proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

medial coronoid process around the radial head to attach to the lateral surface of the proximal ulna. The medial portion of this ligament can be seen medial and cranial to the medial collateral ligament with the telescope

4.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 4.34  The caudomedial joint space seen with the telescope directed caudally and medially from the medial telescope portal. The joint capsule refection is at the top of the image coming off the bone on the right and the joint capsule covering the origin of the flexor muscles is on the left. Proximal is up and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.36  A small pars nudosa at approximately the middle of the semilunar notch containing a small quantity of fat. The lateral ridge of the humeral condyle fills the top of the image and the ulna extends across the bottom. Proximal or dorsal is up and cranial is to the right. The telescope is looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.37  A small deep pars nudosa of the ulnar articular surface. The lateral ridge of the humeral condyle fills the top of the image and the ulna extends across the bottom. Proximal or dorsal is up and cranial is to the left. The telescope is looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.35  The caudomedial joint space seen with distal angulation from the image in the previous figure. The medial surface of the epiphysis of the humerus is on the right and the tendons of origin of the flexor muscles is on the left. Proximal is up and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

directed cranially and medially from the medial telescope portal (Figure 4.39). Intra-articular fat is a common finding and is seen in many areas of the elbow joint (Figures  4.6, 4.9, 4.22, 4.27, 4.31–4.33, and 4.36).

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4.5 ­Diseases of the Elbow Diagnosed and Managed with Arthroscopy 4.5.1  Elbow Dysplasia

Figure 4.38  A large pars nudosa occupying a significant portion of the ulnar articular surface centered at the cranial end of the ridge of the semilunar notch. A small portion of the lateral ridge of the humeral condyle is to the upper right, a small portion of the caudal margin of the radial head is to the upper left, and the ulna fills the remainder of the image. Proximal is up and cranial is to the left with the telescope looking laterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.39  The medial end of the ligament of the radial head seen cranial and medial to the medial collateral ligament with the telescope directed cranially from a medial portal. The medial collateral ligament is seen on the right with craniomedial margin of the tip of the medial coronoid process seen in the lower right, and the ligament of the radial head is seen traversing obliquely across the upper left of the picture. Dorsal is up and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

This entity has gone through a series of names over the past 30 years in an attempt to more accurately refer to a combination of abnormalities of the elbow joint. First called elbow dysplasia, then fragmented coronoid process (FCP), elbow incongruity, medial coronoid process disease (MCPD), medial coronoid process pathology (MCPP), and medial compartment syndrome (MCS). None of these names are any better suited than the others and none accurately describe the variation of underlying pathology. The first name, elbow dysplasia, is as good as any of the more recent monikers and more accurately describes our lack of understanding of this elbow joint pathology. The term elbow dysplasia when first used included ununited anconeal process and any degenerative changes seen on radiographs without other specific diagnoses, as they had not been defined at that time. With the addition of diagnoses including OCD, abnormal formation of the medial coronoid process, and abnormal interaction of the ulna with the radial head and humeral condyle, the term elbow dysplasia encompasses this spectrum of diseases but with more variation allowed. Many theories have been discussed and published concerning the underlying etiology of elbow dysplasia. The more that is said, the more that is published, and the more elbow cases that are done the less is understood about the elbow. None of the current theories seem to cover all the changes that are seen. There are many interacting factors that come from multiple abnormalities that do not yet have answers. The need to keep looking and continue to question all the presented theories is definitely still present and will continue until we have a complete understanding of this disease. In addition to pathology associated with interaction of the humeral condyle with the radial head and ulnar articular surface, there may also be pathology involving articulation of the articular circumference of the radial head with the radial notch of the ulna. If these two surfaces are not congruent then abnormal forces occur with subsequent fragmentation of the axial or lateral aspect of the medial coronoid process. Many medial coronoid process fragments fit this concept as an etiology. But this is not the only etiology. I do not have the answers. Most of the theories presented look only at the adult elbow joint. The

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

r­ elationships of the involved bones during growth have not been studied and consideration needs to be given to possible changes during growth. In thinking about the changes seen in some elbow joints, it is evident that the relationship of radial and ulnar length, specifically the relationship of the weight-bearing surfaces of the radial head to the semilunar notch, may not be the same during all phases of growth as it is in the adult dog. This could account for changes in both the coronoid process and the anconeal process. This could also account for an abnormal medial coronoid process with cartilage loss that sits below the level of the radial head. Or is the pathology in the humeral condyle from abnormal circumference or varus–valgus angulation. The remaining questions far overshadow the current answers. A complete discussion of the history, theories, and pathophysiology of elbow dysplasia is beyond the scope of this work. The focus of this book is aimed at the applications, procedures, and techniques of arthroscopy. Those interested in gaining further knowledge on the abnormalities of the elbow need to pursue this in other publications. The comments in the previous paragraphs are the opinions of the author developed with 37 years of experience performing elbow arthroscopy, reading many of the publications on elbow disease, independent discussions with other surgeons, and group discussions with other surgeons at meetings. Elbow dysplasia is the most common indication for, and diagnosis achieved with arthroscopy of the elbow joint. Arthroscopy of the elbow joint is indicated with front leg lameness in medium to large breed dogs when there is elbow joint pain, swelling, thickening, reduced range of motion, or there are any radiographic changes present in the elbow joint. Medial coronoid process changes are diagnosed primarily in young dogs but have been seen as an acute onset lameness in dogs as old as nine years. Definitive differentiation of the etiology of radiographic change is not necessary before arthroscopy as arthroscopy will allow determination of the diagnosis. The most common conditions seen in the elbow joint, medial coronoid process disease, ununited anconeal process, and OCD, are approached through the same medial telescope portal. Elbow CT is a very important addition to understanding the changes in individual elbows (Botazzoli et  al.  2008; Coppieters et  al.  2016a,  b; Eljack and Böttcher  2015; Griffon et  al.  2018; Groth et  al.  2009; Kramer et  al.  2006; Krotscheck et  al.  2014; Lau et  al.  2015; Moores et  al.  2008; Skinner et  al.  2015; Villamonte-Chevalier et  al.  2015; Wagner et  al.  2007) but is not needed for arthroscopy to be indicated and performed. Elbow

­ ysplasia is commonly a bilateral disease process and d bilateral elbow arthroscopy is routinely recommended even in the presence of unilateral presentation. Unilateral presentation does not necessarily indicate unilateral involvement but may only indicate that the presenting elbow is more painful than the nonclinical elbow. In many cases, it seems that more benefit is achieved with arthroscopy for the asymptomatic joint than for the joint of presentation because it is treated at an earlier stage with less joint damage. It is also far easier for the patient and more economical for the client to perform a bilateral procedure than two independent unilateral procedures. There are many open surgical procedures applied to the elbow joint for management of elbow dysplasia. Various forms of elbow osteotomy with or without fixation are the most common of these procedures. The primary humeral procedure is sliding humeral osteotomy. Open intraarticular procedures are also included in this list. It is the authors’ opinion that there is no science that supports any of these open surgical procedures providing any better long-term results than arthroscopy by itself. These open surgeries are unnecessarily invasive, traumatic, and painful. They also require prolonged recovery and induce the risk for failure of the osteotomy to heal. For these reasons, it is the authors’ opinion that these open surgeries are not indicated. In line with Noel Fitzpatrick’s statement in an elbow dysplasia session at a recent ACVS Symposium, “There is nothing we can do to prevent progression of degenerative joint disease of the elbow joint.” If we believe in this statement and it probably is true, then all we are doing is pain management. The list of open surgeries, especially those involving osteotomies, cause pain for a significant period of time and there is no science to support that long-term pain is reduced more than with arthroscopy alone. Arthroscopy for elbow dysplasia is performed through a medial telescope portal and a craniomedial operative portal (Figure 4.1). An additional caudomedial operative portal is required when there is an ununited anconeal process and is at the site shown for the egress portal (Figure  4.1). Egress is typically through the operative portal. An egress portal can be placed in the caudal compartment of the joint if needed but is seldom required. Medial coronoid process disease is typically easily visible, but some lesions are subtle and are not easily seen on initial examination of the joint. There is an extensive variety of pathology that can be present with a wide presentation of lesion severity. The wide variation of lesions that are seen also indicates that this is not a single disease

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process but is a variety of different abnormalities producing a wide range of distinctly different lesions. There is a wide range in size of free medial coronoid process fragments from small (Figure 4.40), to medium (Figure  4.41a and b), large (Figure  4.42), massive (Figure  4.43), and there can be multiple fragments of various sizes (Figures 4.44 and 4.45). Small coronoid process fragments with no other pathology are seen in only a small percentage of cases (Video 4.1). In these cases, normal cartilage is present on the free fragment, the fixed portion of the medial coronoid process, and on the medial ridge of the humeral condyle (Figure 4.46). Small free fragments are also seen with all grades of cartilage damage (Video 4.2). Classic larger free coronoid process fragments (Figure  4.42) and multiple fragments (Figure 4.47) are also occasionally seen with normal cartilage surfaces (Videos 4.3 and 4.4). Medial coronoid process fragments are most commonly free or loose movable

Figure 4.40  A small free medial coronoid process fragment on the lateral margin of the medial coronoid process is seen as a bright white area slightly to the left of center on the image. Cartilage is present on the free fragment with full thickness cartilage loss on both the fixed portion of the coronoid process and on the medial ridge of the humeral condyle. The full thickness cartilage loss with exposed eburnated bone represents Grade V chondromalacia. The humeral condyle is visible across the top of the figure with normal cartilage at the far left and exposed bone with a pink color from the cartilage margin to the right side of picture. The medial coronoid process fills the lower right as exposed bone with no cartilage other than on the free fragment. The radial head is seen to the left of the medial coronoid process with an indistinct margin between the two bones. There is cartilage on most of the radial head but a small area to the right of the free fragment is exposed radial head bone. Dorsal, or proximal, is up on the picture with medial to the right, cranial to the upper right, and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.41  (a) A medium size free medial coronoid process fragment with normal cartilage on the fragment, normal cartilage on the fixed portion of the medial coronoid process, and normal cartilage on the medial ridge of the humeral condyle. In this image proximal, or dorsal, is up with medial to the left and the telescope is looking craniolaterally from a medial portal. The free fragment fills the center of the figure with a clear fracture line, fixed medial coronoid process is to the left and bottom, radial head is to the right, and humeral condyle is to the upper right. (b) A medium size loose medial coronoid process fragment is seen in the center of the image with normal cartilage on the fragment. The fixed portion of the medial coronoid process is to the right and across the bottom of the figure with a small area of full thickness cartilage loss (Grade IV chondromalacia) below the fragment plus irregular cartilage (Grade II chondromalacia) to the right. The humeral condyle extends across the top of the picture with an area of partial thickness cartilage erosion is seen in the upper center on the medial ridge of the humoral condyle (Grade III chondromalacia). Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking cranially from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

bone as shown in the previous figures, but “fixed” fragments are not uncommon (Video 4.5). Many fragments are obviously loose, but the status of other fragments is

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.42  A large free medial coronoid process fragment on the lateral margin of the medial coronoid process extending across the midlevel of the image with Grade I chondromalacia, cartilage swelling, on the free fragment. Normal cartilage is present on the fixed portion of the medial coronoid process seen across the bottom of the image and on the medial ridge of the humeral condyle at the top. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.43  A massive free medial coronoid process fragment extending across the midlevel of the image (The largest seen by the author) comprising the entire lateral margin of the medial coronoid process with Grade II chondromalacia on the free fragment. Full thickness cartilage loss (Grade V chondromalacia) is seen both on the fixed portion of the medial coronoid process at the bottom of the figure and on the medial ridge of the humeral condyle where it contacts the fixed portion of the medial coronoid process at the top. The humeral condyle cartilage loss is where it contacts the fixed portion of the medial coronoid process but not where it contacts the free fragment. The needle seen entering the right side of the image was placed in preparation for creation of a craniomedial operative portal. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.44  Three, two distinct and one indistinct, small free medial coronoid process fragments at the base of the lateral margin of the medial coronoid process in an elbow with full thickness cartilage loss on the medial ridge of the humeral condyle and on an area of the base of the fixed portion of the medial coronoid process. The free fragments are covered with cartilage but are too small to accurately assess the degree of chondromalacia. The medial ridge of the humeral condyle across the top of the image and fixed portion of the medial coronoid process across the bottom both show Grade V chondromalacia. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.45  Two large free medial coronoid process fragments comprising the complete lateral margin of the medial coronoid process are seen filling the midlevel of the image with normal cartilage on the arthrolith to the left and irregular cartilage (Grade II chondromalacia) on the one to the right. Full thickness cartilage loss exposing bone (Grade IV chondromalacia) is seen on the on the medial ridge of the humeral condyle at the top and a small area of full thickness cartilage wear (Grade IV chondromalacia) is seen on the fixed portion of the base of the medial coronoid process at the lower right. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.46  A small free medial coronoid process fragment with normal cartilage on the free fragment in the center of the image, on the humeral condyle at the top, and on the fixed portion of the medial coronoid process to the left and bottom of the image. There is a clear line of demarcation between the fragment and fixed bone. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.47  Two free medial coronoid process fragments on the lateral margin of the medial coronoid process with normal cartilage on the medial ridge of the humeral condyle at the top, on the fixed portion of the medial coronoid process across the bottom, and on the free fragments in the center. The left or caudal fragment has a clear line of demarcation with the right fragment being less clearly defined. Palpation confirmed that both fragments were easily movable and were loose or free fragments. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

only determined by palpation for movement (Video 4.6). Fixed fragments have the same range of size from small (Figure 4.48), medium (Figure 4.49), to large (Figure 4.50),

Figure 4.48  A very small fixed medial coronoid process fragment on the lateral margin of the medial coronoid process to the left of center seen as a subtle semicircle line in the cartilage. The fragment did not move with joint manipulation or palpation using a probe. There is normal cartilage on all visible joint surfaces including the humeral condyle to the upper right, the medial margin of the radial head to the right of radial-ulnar articulation below the humeral condyle, and on the medial coronoid process seen obliquely across the lower left. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.49  A medium sized fixed coronoid process fragment on the lateral margin of the medial coronoid process to the right of center with normal cartilage on its articular surface and a clear line of demarcation in the cartilage. Two small areas of Grade II chondromalacia are seen on the lateral margin of the fragment with one at its midpoint and one at the caudal end. Normal cartilage is present on the medial ridge of the humeral condyle across the top, on the radial head to the left, and on the fixed portion of the medial coronoid process to the bottom and far right. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.50  A large, fixed fragment on the lateral margin of the medial coronoid process with normal cartilage on all visible joint surfaces. A subtle line is visible in the cartilage defining the margin of the fragment. Humeral condyle is at the top, radial head to the left, with the medial coronoid process filling the lower right, and the fixed fragment situated obliquely across the center of the image. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

and multiple (Figure 4.51) as do free fragments. Free and fixed fragments can be present in the same joint (Figure  4.52) (Video 4.7) or fixed fragments present in one joint (Figure 4.47) with a free fragment in the contralateral joint (Figure 4.53). The margins of fixed fragments can be clearly seen in some patients as a linear cartilage defect with no cartilage damage other than this linear defect (Figures  4.48–4.51), as indistinct linear chondromalacia (Figure 4.54), or as distinct linear cartilage mineralization (Figure  4.55). In other cases, there may be no visible margin with overlying normal cartilage (Figure 4.56), there may be no visible margin because the margin is obscured by chondromalacia (Figures  4.57 and 4.58), or the margin can be seen when there is Grade V chondromalacia and a fissure line is visible in the exposed bone (Figures  4.59 and  4.60). Fixed fragments that are hidden by normal cartilage or chondromalacia are best diagnosed with preoperative CT studies that define fissure lines. The hidden fissure lines can also be found by removal of the overlying cartilage (Figure 4.61). Cartilage pathology is not related to free fragment size as small lesions are seen with extensive cartilage loss (Figure  4.40) and large fragments occur with minimal or no cartilage damage (Figure 4.50). Medial coronoid process fragments most commonly arise from the lateral

Figure 4.51  A multipart fixed fragment on the lateral margin of the medial coronoid process with normal cartilage on all joint surfaces. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. The medial ridge of the humeral condyle is seen across the top of the image with a small portion of lateral humeral condyle ridge to the far right, medial coronoid process is to the lower left and the radial head is seen to the right of the coronoid process. The caudal fixed fragment has a clear cartilage line defining its margin and separation from the cranial fixed fragment but the cartilage line defining the lateral margin of the cranial fragment is less clear. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.52  Fixed and free medial coronoid process fragments in the same elbow joint with the free fragment concentrically positioned in the fixed fragment. The free fragment is seen in the center of the image to the left of the tip of the needle with the fixed fragment below and to the right of the free fragment with a clear line of demarcation. Normal cartilage is present on the humeral condyle across the top and on the radial head in the background to the left. Grade II chondromalacia is present on the fixed portion of the medial coronoid process at the bottom and lower right. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.53  A free medial coronoid process fragment in the contralateral elbow joint in the dog with a fixed fragment in the joint shown in Figure 4.48. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Humeral condyle is seen across the top, the fixed portion of the medial coronoid process is to the lower left and bottom, the radial head is in the background to the right, and the free fragment is to the left of center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.54  A fixed medial coronoid process fragment with an indistinct linear margin of Grade II chondromalacia running obliquely from the lower left to the right of the image. Humeral condyle is to the upper left, radial head to the left, medial coronoid process to the lower right, and reactive cranial compartment synovium in the background of the upper center of the picture. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

side of the medial coronoid process occurring at any position along that margin, cranially (Figures 4.41, 4.46, 4.53), in the middle (Figures 4.40, 4.48–4.50), at the base

Figure 4.55  Distinct linear mineralization of cartilage defining the margin of a fixed medial coronoid process fragment seen running horizontally across the lower portion of the image as a raised irregular band with slightly yellow coloration compared to the surrounding normal cartilage. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Radial head fills the top of the image, the medial coronoid process fills the bottom, and the fixed fragment is on the lateral margin of the coronoid process above the line of demarcation. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.56  A medial coronoid process with a fixed fragment that is completely hidden with normal cartilage. The only visible indication of pathology is a small area of Grade I chondromalacia on the lateral margin of the medial coronoid process seen as a slightly irregular and lighter colored tissue. In this patient a fissure line was visible on CT and was exposed when the overlying cartilage was removed. Humeral condyle is to the upper right, medial coronoid process fills the lower left, radial head is between these two bones in the background, and medial collateral ligament is to the upper left. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure 4.44), or can be the entire lateral margin of the process (Figures  4.42, 4.43, 4.45, 4.47, 4.51, 4.52). Fragments can also arise from other parts of the medial coronoid process including the apex (Figure  4.62) and uncommonly the medial margin (Figure 4.63).

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.57  Grade III chondromalacia on the medial coronoid process obscuring the margin of a fixed medial coronoid process fragment. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Humeral condyle is to the upper left with normal cartilage, medial coronoid process fills the lower right of the image with an irregular cartilage surface becoming more severe towards the upper left along its lateral margin, and a small portion of radial head is visible to the far left. A fissure line was defined with CT and the margin of the fixed fragment is seen after cartilage removal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.58  Another example of Grade III chondromalacia on the medial coronoid process obscuring the margin of a fixed medial coronoid process fragment. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Humeral condyle is at the top with medial coronoid process filling the bottom of the image. Normal cartilage is present on the humeral condyle and on the medial portion of the medial coronoid process articular surface with progressively worsening chondromalacia from the medial normal cartilage to the lateral margin of the process. Cartilage removal revealed a demarcation line in the bone that corresponded with the transition from normal cartilage to chondromalacia. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.59  The margin or fissure line defining a fixed medial coronoid process fragment on the lateral margin of the medial coronoid process is seen as a white line in the exposed bone because of the Grade V chondromalacia. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. Humeral condyle with exposed bone is to the upper left, exposed bone of the medial coronoid process fills the lower right, the fixed fragment is to the upper left of the exposed medial coronoid process, Grade IV chondromalacia on the radial head is in the background to the left, and the separation of radius and ulna is seen as a band if frayed irregular white cartilage running from the top to the lower left of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.60  A fissure line with residual cartilage defining the margin of a fixed medial coronoid process fragment exposed by complete loss of cartilage on both sides of the fissure line. The humeral condyle fills the top of the image with exposed bone to the left and a feathered cartilage margin running obliquely across the articular surface with thinned worn cartilage containing glaciation groves to the right. The medial coronoid process fills the bottom of the figure with the demarcation or fissure line seen as the white band running obliquely from right to lower left. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.61  A fissure line defining the margin of a fixed medial coronoid process exposed by removal of overlying cartilage using an arthroscopic shaver with a burr. The fragment was fixed prior to removal of cartilage and bone. The fragment became loose during the shaving procedure as can be seen by the open fissure line. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking craniolaterally from a medial portal. The shaver burr was inserted through a craniomedial operative portal. The fissure line is seen as a narrow dark line extending from the shaver burr down with a slight curve to the left. Bone to the right is the medial fixed portion of the medial coronoid process and whiter bone to the left of the fissure represents the fragment. Debris created by the shaver obscures the lateral margin of the fragment and structures to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.62  A free fragment at the cranial tip of the medial coronoid process. Dorsal, or proximal, is up on the picture with medial to the left and the telescope is looking cranially from a medial portal. The free fragment is the irregular tissue in the center of the image. Humeral condyle is to the upper right, the fixed portion of the medial coronoid process is at the bottom, radial head is to the far right, and the medial collateral ligament is indistinct in the background to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Chondromalacia involving the medial coronoid process can be minimal with low-grade minor changes involving small areas of the joint surface to full thickness cartilage loss with eburnation of exposed bone over

Figure 4.63  An unusual free fragment originating from the medial margin of the medial coronoid process. Dorsal, or proximal, is up on the picture with medial to the right and the telescope is looking cranially from a medial portal. The fragment fills the center of the image with humeral condyle across the top, the fixed portion of the medial coronoid process to the left, and the bone defect where the fragment originated is seen at the bottom of the picture filled with hyperemic villus synovial reactive tissue. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

an extensive area of the ulnar articular surface. Table 3.1 defines the modified Outerbridge chondromalacia grading system (Griffon  2012; Outerbridge  1961) used in these descriptions. Medial coronoid process disease is uncommonly seen with normal cartilage on all structures within the joint (Figures  4.41, 4.46–4.48, 4.50, and 4.51). More commonly there is damage to cartilage on the fixed portion of the medial coronoid process with the grade of chondromalacia seen on free medial coronoid process fragments typically being much less than that seen on the fixed portion of the medial coronoid process (Figures 4.40–4.45). Small Grade I lesions on the fixed portion of the medial coronoid process are seen showing blistering (Figure 4.64), softening (Figure 4.65), or swelling (Figure  4.56). Grade II lesions are seen as small areas with fibrillation (Figure  4.66), fissures (Figure 4.67), or loss of cartilage thickness (Figure 4.68). Larger lesions with deeper cartilage involvement represent Grade III chondromalacia with fibrillation (Figure  4.58), fissures, uniform loss of cartilage thickness (Figure 4.69), or loss of cartilage thickness with a moth-eaten appearance (Figure  4.57). Grade IV chondromalacia signifies full thickness cartilage damage with exposed bone (Figure 4.70) seen as uniform loss of cartilage thickness (Figure  4.45) or irregular motheaten cartilage loss (Figure 4.71). Grade V chondromalacia is seen on the fixed portion of the medial coronoid process as complete loss of cartilage and smooth exposed and eburnated bone with feathered cartilage margins (Figures 4.40, 4.44, and 4.60).

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.64  A cartilage blister, Grade I chondromalacia, on the lateral margin of the medial coronoid process representing subtle medial coronoid process pathology. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. The bright white areas are mineralized cartilage. The medial coronoid process is to the lower left with the radial head to the upper right and cranial joint capsule with villus synovial reaction is to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.65  A band of soft cartilage seen as a narrow band of slightly darker tissue on the lateral margin of the medial coronoid process, Grade I chondromalacia, is another example of subtle medial coronoid process pathology. The telescope is looking cranially from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Humeral condyle extends across the top of the image with medial coronoid process across the bottom, radial head is to the left between the two bones, and reactive synovium is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Chondromalacia also commonly occurs on the humoral condyle with all Grades being seen. Minor or Grade I chondromalacia appears as swelling (Figure  4.72), blisters (Figure  4.73), or softening (Figure 4.74). Small partial thickness, Grade II chondromalacia, including erosions (Figure 4.75), partial thick-

Figure 4.66  A small area of cartilage fibrillation, Grade II chondromalacia, on the base of the lateral margin of the medial coronoid process in an elbow with a small fixed medial coronoid process fragment. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Humeral condyle is to the upper left, ulnar articular surface fills the lower right of the image with radial head in the background. The radial-ulnar articulation runs from the upper right to the lower left and the area of chondromalacia is the slightly fuzzy margin of the ulna where it articulates with the radial head. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.67  Grade II chondromalacia on the lateral margin of the medial coronoid process represented by fissure lines and fibrillation. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. The medial coronoid process fills the lower right of the image with radial head in the background and humeral condyle across the top. The area of chondromalacia is seen as irregular tissue on the near side of the radial-ulnar articulation running from the upper right to the lower left. An area of humeral condyle chondromalacia is also present at the upper right of the image but the severity cannot be determined in this picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.68  An area of loss of cartilage thickness at the tip of the medial coronoid process representing Grade II chondromalacia. The medial coronoid process fills the bottom of the image with its cranial margin running horizontally across the upper center to the right edge of the picture, the lateral margin runs from the upper center down to the lower left, humeral condyle is to the upper left, joint capsule is to the upper right, and the radial head is to the left seen between the humeral condyle and the lateral margin of the medial coronoid process. The area of chondromalacia is the slightly darker triangle of cartilage formed by the two visible sides of the medial coronoid process and with its base running as a straight line from the right to the lower left. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.69  Uniform loss of cartilage thickness over a large area of the fixed portion of the medial coronoid process, Grade III chondromalacia, fills the lower left of the image. The small area of full thickness cartilage loss near the center of the image is iatrogenic. The large free medial coronoid process fragment is seen beyond the lateral margin of the medial coronoid process is covered with swollen cartilage demonstrating Grade I chondromalacia. A small portion of humeral condyle is visible to the upper right above the coronoid process fragment. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.70  Grade IV chondromalacia on the tip of the fixed portion of the medial coronoid process showing pink exposed bone extending across the bottom of the image. A coronoid process fragment covered with more normal cartilage, Grade II chondromalacia, is seen to the right of the exposed bone without a visible fragment margin. Palpation with a probe determined that this was a free fragment. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. A small portion of humeral condyle is to the upper right, medial collateral ligament is the vertical band of smooth white tissue just to the right of center between the humeral condyle and the coronoid process, and craniolateral joint capsule is the fuzzy tissue with visible blood vessels to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.71  Grade IV chondromalacia on the fixed portion of the medial coronoid process appearing as moth-eaten cartilage with small areas of exposed bone. The medial coronoid process fills the lower left of the image, an area of humeral condyle is to the upper right, a short segment of medial collateral ligament is seen in the upper center, and a small bit of radial head is to the far right. The needle visible in the image is positioned to locate the appropriate site for operative portal placement. A small coronoid process fragment is present behind the middle of the needle with the needle obscuring the fragment from the medial coronoid process. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.72  Irregular swelling, Grade I chondromalacia, of cartilage on the trochlea of the humeral condyle. Grade II chondromalacia is seen as roughened cartilage on the medial margin of the radial head and on the lateral margin of the base of the medial coronoid process. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Humeral condyle extends across the top of the figure with its medial ridge to the right, the lateral ridge to the lower left, and the valley of the trochlea in the center. Medial coronoid process is to the lower right with radial head seen between the two other bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.73  Grade I chondromalacia of cartilage on the humeral trochlea demonstrated as a single blister. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. The humeral condyle is to the upper right, radial head is below the humerus behind the needle, and a small portion of ulna is visible to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.74  Soft cartilage on the trochlea of the humeral condyle with subtle variation in cartilage coloration seen as another presentation of Grade I chondromalacia. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Humeral condyle fills most of the image with reactive synovium to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.75  Grade II chondromalacia of the humeral condyle cartilage demonstrated as a small shallow cartilage erosion seen toward the right side of the picture. Grade II chondromalacia is also present on the free coronoid process fragment prominently seen in the center of the image and on the fixed portion of the base of the medial coronoid process to the lower right. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

ness wear lesions (Figure 4.76), fibrillation (Figure 4.77), or moth-eaten cartilage (Figure  4.78). Grade III chondromalacia lesions have the same range of appearance as Grade II lesions but are larger and deeper but do not

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Figure 4.76  A wear lesion, Grade II chondromalacia, in the cartilage of the humeral trochlea caused by contact with the large coronoid process fragment seen in the left center of the image with its caudal margin exposed above the fixed medial coronoid process visible at the bottom. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.77  A small area of shallow cartilage fibrillation, Grade II chondromalacia, on the right half of the exposed medial ridge of the humeral condyle that fills the upper image. The telescope is looking cranially from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

penetrate to bone. Erosions (Figure 4.79), wear lesions as single grooves (Figure  4.80) or widespread cartilage damage (Figure 4.81), cartilage fibrillation (Figures 4.80 and 4.82), moth-eaten cartilage (Figure 4.83), and cartilage fissures (Figure 4.84) are all representative of Grade III chondromalacia. Progression to exposed bone is termed Grade IV chondromalacia and is also expressed as erosions (Figures  4.45 and  4.85), wear lesions (Figure  4.86), cartilage fibrillation (Figure  4.87), and moth-eaten cartilage (Figure 4.88). Extensive full thickness lesions with eburnation of exposed bone are given the category of Grade V chondromalacia. This grade was

Figure 4.78  Moth-eaten appearance of the humeral condylar cartilage with Grade II severity seen as subtle irregular variation in coloration in the center and to the right of the visible condyle. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. The humeral condyle fills the image with a small portion of ulna seen across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.79  Humeral condyle fills the upper image with cartilage erosions that are deeper and more extensive than the previously seen lesions and represent Grade III chondromalacia. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. Radial head is visible to the lower right, a coronoid process fragment is seen indistinctly to the left with irregular cartilage obscuring the margins of the fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

added to the original four Outerbridge grades as part of the “Modified” grading system (Griffon 2012) and is specifically suited to categorizing elbow pathology. Full thickness wear lesions are commonly seen on the medial ridge of the humeral condyle (Figures  4.40, 4.43, 4.44, and  4.60) and chondromalacia occasionally extends laterally onto the trochlea of the humeral condyle as Grade II (Figure 4.89), Grade III (Figure 4.90), Grade IV (Figure 4.91), and Grade V (Figure 4.92) lesions.

Figure 4.80  A single deep cartilage wear groove in the humeral condyle cartilage and cartilage fibrillation both representing Grade III chondromalacia. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. A small area of ulna is seen at the bottom with the humeral condyle filling the upper image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.81  Grade III chondromalacia of the humeral condyle to the left and ulnar cartilage to the right demonstrated as multiple wear grooves over a wide area. This wear pattern has been termed glaciation. The telescope is looking caudolaterally from a medial portal with proximal, or dorsal, to the left on the image and medial is to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.82  Grade III chondromalacia of the humeral condylar cartilage at the top presenting as fibrillation with Grade II chondromalacia on the opposing area of the ulnar articular cartilage seen across the bottom of the image. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.83  An extensive area of moth-eaten cartilage is seen on the right half of the humeral condyle representing Grade III chondromalacia. The telescope is looking craniolaterally from a medial portal with humeral condyle filling the top, dorsal or proximal, portion of the image with the radial head laterally to the left, ulna at the bottom, and reactive joint capsule in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.84  Fissures in the humeral condyle joint cartilage, representing Grade III chondromalacia, seen as a pattern of fine dark lines in the center of the picture. The telescope is looking laterally from a medial portal with cranial to the left and dorsal or proximal up on the image. The humeral condyle fills the top of the image with the semilunar notch of the ulna at the bottom in the foreground and radial head in the background to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.85  The humeral condyle fills the top of the image with moth-eaten cartilage extending to full thickness exposing bone and representing Grade IV chondromalacia. The telescope is looking cranially from a medial portal with proximal, or dorsal, up on the image and medial is to the right. The humeral condyle fills most of the image and medial coronoid process is to the lower right with a indistinctly visible fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.86  A full thickness groove worn in the humeral condyle cartilage, Grade IV chondromalacia with normal cartilage to the right and Grade III chondromalacia to the left. The humeral condyle fills the top of the image with dorsal up, ulnar articular surface is at the bottom, and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.88  Moth eaten cartilage with exposed bone, Grade IV chondromalacia, on the medial ridge of the humeral condyle. In this image it is not possible to tell if the cartilage present is the remnants of original cartilage representing Grade IV chondromalacia or if this is cartilage regeneration over an area of Grade V chondromalacia. Grade V chondromalacia is present on the visible portion of the fixed portion of the medial coronoid process seen at the lower left. Radial head is seen in the background. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up to the right on the image and medial is up to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.87  The humeral condyle is seen across the top of the image with cartilage fibrillation to the right and with exposed bone to the left side placing this into Grade IV chondromalacia. Grade V chondromalacia is visible on the fixed portion of the medial coronoid process in the lower left of the image with Grade III chondromalacia on the free fragment seen to the lower right. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Radial head cartilage lesions are less commonly seen with medial coronoid process disease but all Grades and appearances of chondromalacia are represented. Mild chondromalacia lesions including Grade I focal swelling (Figure  4.93) and generalized swelling (Figure  4.94), Grade II erosions (Figures 4.67 and 4.72), Grade II wear lesions (Figure  4.95), Grade II moth-eaten cartilage

Figure 4.89  Partial thickness cartilage wear, Grade II chondromalacia, is seen extending laterally onto the trochlea of the humeral condyle at the transition from an area of full thickness, Grade V chondromalacia, on the medial ridge of the humeral condyle. Grade V chondromalacia is present on the ulnar articular surface at the base of the semilunar notch. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image with medial to the right. Humeral condyle fills the top of the picture with ulna across the bottom and small portion of radial head to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.90  A groove of Grade III chondromalacia is seen in the trochlea of the humeral condyle as transition from Grade V chondromalacia on the medial ridge on the right into Grade II chondromalacia on the left. The telescope is looking caudolaterally from a medial portal with proximal, or dorsal, up on the image and medial to the right. Humeral condyle fills the top of the image with a small area of anconeal process in the background to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.92  Extension of Grade V chondromalacia from the medial ridge of the humeral condyle at the top of the image into the trochlea on the right. Grade V chondromalacia is also present on the radial head in the center of the image and the ulnar articular surface to the lower left. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, to the upper right on the image and medial is to the upper left. The intermittent white band of tissue running from the lower right to the upper left is the articulation of radius and ulna. The wider white area to the upper left is a free coronoid process fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.91  Grade IV chondromalacia seen as grooves in the trochlea of the humeral condyle at the transition from Grade V chondromalacia on the medial humeral condylar ridge at the top of the image into normal cartilage on the right. A Grade V lesion is also seen on the medial portion of the radial head to the left and below the medial humeral condyle with a Grade IV lesion on the ulnar articular surface across the bottom. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial to the left. The irregular band of white tissue running horizontally across the picture is the articulation of the radial head with the ulna. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.93  Focal Grade I chondromalacia, irregular swelling, is seen on the caudal margin of the radial head to the right adjacent to the lateral coronoid process of the ulna visible to the left. There is also a small area of Grade II chondromalacia on the trochlea of the humeral condyle seen as fibrillated cartilage at the top of the picture. The prominent hyperemic tissue in the center of the picture is reactive synovial tissue in the pars nudosa of the ulna. The telescope is looking laterally from a medial portal with proximal, or dorsal, up on the image and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.94  Generalized Grade I chondromalacia, irregular swelling, of radial head cartilage. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial is to the left. Normal cartilage on the humeral condyle fills the upper right of the image with ulna to the lower left and the radial head is seen between the other two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.95  The articular surface of the radial head fills the bottom of the image with Grade II chondromalacia wear lesions extending across the radial head becoming more prominent to the right. Humeral condyle fills the top of the picture with dorsal or proximal up and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure 4.96), Grade III cartilage erosions (Figure 4.97), and Grade III fissures (Figure 4.98) are all seen on the radial head. More severe chondromalacia is most ­commonly represented as wear lesions including Grade IV (Figure  4.40) and Grade V (Figures  4.91 and  4.92). When this degree of cartilage damage is seen all three bones are typically involved with Grade V chondromalacia.

Figure 4.96  Grade II moth-eaten cartilage seen in the center of the figure on the medial margin of the radial head. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial to the right. Humeral condyle is to the upper left and ulna is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.97  Grade III cartilage erosions on the radial head. The telescope is looking craniolaterally from a medial portal with proximal, or dorsal, up on the image and medial to the right. The hook probe visible in the picture is inserted through a craniomedial operative portal. The radial head is seen in the lower left of the image with a small portion of the base of the medial coronoid process in the lower right and humeral condyle at the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Chondromalacia occurs on all areas of the ulnar articular cartilage in addition to the typical lesions seen on the medial coronoid process. Grade I chondromalacia is seen as cartilage swelling on the medial slope and ridge of the trochlear notch (Figure 4.72), on the lateral slope of the

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.98  Grade III chondromalacia seen as a fissure line on the caudal margin of the radial head adjacent to the lateral coronoid process. The telescope is looking laterally from a medial portal with proximal, or dorsal, up on the image and cranial to the right. Humeral condyle fills the upper left, lateral coronoid process is to the lower left, the medial ulnar articular surface is to the lower right, and the radial head is to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

trochlear notch (Figures 4.99 and 4.100), and on the lateral coronoid process (Figures 4.98 and 4.101). Grade II chondromalacia lesions are also seen on multiple areas of the ulnar articular surface including the medial slope of the trochlear notch (Figure  4.102), on the ridge of the semilunar notch (Figures 4.103 and 4.104), on the lateral coronoid process (Figure 4.105), and on the anconeal process (Figure 4.106). More severe and extensive, Grade III chondromalacia, lesions are also seen on the cartilage of the medial slope of the trochlear notch (Figure 4.107), on the ridge of the anconeal notch (Figure 4.108), on the lateral coronoid process (Figure 4.109), and on the anconeal process (Figures 4.81 and 4.110). Grade IV chondromalacia has not been seen extending beyond the medial slope of the trochlear notch but is more commonly seen on this part of the joint cartilage as wear lesions (Figures 4.111 and 4.112) or as cartilage with a moth-eaten appearance (Figure 4.57). Grade V chondromalacia, complete loss if cartilage with eburnation of the exposed bone, is far more common than Grade IV chondromalacia with medial coronoid process disease. Grade V lesions on the ulna are primarily confined to the medial slope and ridge of the trochlear notch (Figures 4.44, 4.89, 4.91, 4.92, and 4.113). The margins of Grade V lesions are typically tapered from normal cartilage to a fine feathered edge (Figures  4.40, 4.44, 4.60, 4.88–4.92) but can occasionally be seen with a roughened margin (Figures 4.91, 4.92, 4.113, and 4.114).

Figure 4.99  Grade I chondromalacia is seen on the lateral slope of the trochlear notch articular cartilage shown as irregular cartilage swelling. The telescope is looking laterally from a medial portal with dorsal, or proximal, up on the image and cranial is to the right. Humeral condyle fills the upper left of the image with ulna filling the lower right and lateral joint capsule is in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.100  Grade I chondromalacia is seen on the lateral slope of the trochlear notch articular cartilage with a different appearance of the cartilage swelling. The telescope is looking laterally from a medial portal and is rotated to an oblique position putting dorsal, or proximal, on the right side of the image with cranial at the top of the picture. Reactive synovium is visible in the background to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

As has been described, the various grades of chondromalacia occur on all three bones of the elbow joint with one, two, or three bones involved. Severe cases can have Grade V lesions on the ulna, humerus, and radial head (Figures 4.91 and 4.92). A wear pattern occurs in elbow joints with medial coronoid process disease that is specific to this disease in this joint. This appears as grooves in

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Figure 4.101  Soft swollen cartilage, Grade I chondromalacia, seen as an irregular surface on the lateral coronoid process. Dorsal, or proximal, is up on the image with cranial to the left and the telescope is looking laterally from a medial portal. Humeral condyle it at the top of the image, radial head is to the left, the ridge of the trochlear notch is at the bottom, and the lateral coronoid process extends into the background to the right of the image center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.103  Grade II chondromalacia with fine fibrillation of articular cartilage on the ridge of the semilunar notch of the ulna. The small cartilage lesion on the humeral condyle to the far-right is iatrogenic. The image is rotated with humeral condyle to the right, which is dorsal or proximal on the image, with cranial is up on the image. The ulna is to the left with radial head indistinctly visible in the upper background between the humerus and ulna. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.102  Cartilage fibrillation on the medial slope of the ulnar articular cartilage representing Grade II chondromalacia. The telescope is looking laterally from a medial portal and the image is rotated in this picture placing dorsal to the right and cranial up. The caudal margin of the radial head is seen as a step protruding above the ulnar articular surface, to the right in the picture, indicating an incongruent joint. Humeral condyle is to the right with ulnar articular surface filling the lower left of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.104  An area of partial thickness cartilage erosion, Grade II chondromalacia, on the ridge of the trochlear notch of the ulna. The telescope is looking caudolaterally from a medial portal and is rotated to place dorsal, or proximal, on the right and caudal toward the top. Humerus fills the right side of the image, ulna is to the left, and the anconeal process is seen extending toward the top of the picture to disappear around the caudal portion of the humeral trochlea. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.105  A band of Grade II chondromalacia extending across the base of the lateral coronoid process. The telescope is looking laterally from a medial portal with cranial to the right and dorsal or proximal toward the top of the image. Humeral condyle fills the top of the image, radial head to the far right, and ulna is across the bottom with lateral coronoid process extending into the center background. Does this cartilage damage indicate a lateral coronoid process fissure line in the underlying bone or is it chondromalacia with underlying normal bone? Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.106  Grade II chondromalacia seen as linear wear grooves in the articular cartilage at the base of the anconeal process. The telescope is looking caudally from the medial portal with proximal, or dorsal to the upper right and medial to the upper left. The caudal trochlear notch of the ulna and base of the anconeal process fill almost all of the image with a rim of humeral condyle to the upper right around the anconeal process. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the cartilage and bone similar to the wear pattern in rocks exposed to glacier activity. Because of this appearance the name “Glaciation” has been attached to this wear pattern by the author. Glaciation is seen on all three of the bones of the elbow joint with all grades of severity. Most commonly, this is seen at the margins of Grade V cartilage

Figure 4.107  Coarse fibrillation of the articular cartilage, Grade III chondromalacia, on the medial slope of the trochlear notch of the ulna. Dorsal is up with the telescope looking laterally from a medial portal. Humeral condyle is seen at the top of the image with ulnar articular surface filling the remainder of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.108  Fine articular cartilage fibrillation on the ridge of the semilunar notch of the ulna, Grade III chondromalacia. The telescope is looking laterally from a medial portal and dorsal or proximal is up. Humeral condyle fills the top half of the picture with ulna filling the bottom half. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

wear lesions on the ulna and humeral condyle extending from normal cartilage to exposed bone (Figures 4.40, 4.60 and 4.113). Glaciation also occurs at the margins of less severe lesions (Figure 4.112), as the lesion itself with all grades of severity (Figures 4.111 and 4.115), and as wear lesions in the exposed bone (Figure 4.89). An unexplainable phenomenon occurs in some joints with the appearance of cartilage regrowth over the eburnated bone of Grade V lesions. This is seen as small islands of cartilage scattered over the eburnated bone

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Figure 4.109  Grade III chondromalacia on the lateral coronoid process of the ulna seen as coarse fibrillation. The telescope is looking laterally from a medial portal with dorsal or proximal to the upper right and cranial to the upper left. Humeral condyle is to the upper right, ulnar articular cartilage to the lower left, and the caudal margin of the radial head is seen at the top of image. The radial head is positioned above the ulna indicating incongruity. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.110  Cartilage fibrillation, Grade III chondromalacia, on the medial articular surface of the anconeal process of the ulna seen as a line of frayed cartilage extending from the center of the picture to the bottom. Normal cartilage on the anconeal process is to the right and reactive joint capsule is to the left. The telescope is looking caudally from a medial portal with the anconeal process to the lower right and the humeral condyle across the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

most commonly on the humeral condyle (Figures 4.88 and 4.116), but is also seen on the ulnar articular surface (Figure 4.117), or on both surfaces (Figure 4.118). This phenomenon can also have a more uniformly distributed appearance of cartilage over the exposed eburnated bone of Grade V lesions (Figure 4.119). In attempting to understand the conditions that would allow this to happen, it is possible that the joint pathology in MCPC is

Figure 4.111  Grade IV chondromalacia appearing as wear grooves, Glaciation, on the medial slope of the trochlear notch of the ulna. Proximal or dorsal is to the upper right with a small area of humerus visible and the remainder of the image is ulnar articular surface. The grooves are aligned with the direction of motion of the opposed bone. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.112  A focal wear lesion, Grade IV chondromalacia, on the medial slope of the trochlear notch of the ulna with exposed bone seen as a slightly darker area across the center of the image. The telescope is looking craniolaterally from the medial portal with medial to the left and dorsal or proximal up on the image. A free medial coronoid process fragment is seen to the left of the wear lesion, the radial head is seen in the background, and a small portion of humeral condyle is to the upper right. Glaciation is seen extending caudally from the margin of the wear lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

caused by asynchronous growth of the radius and ulna creating increase in pressure on the cartilages of the medial joint compartment that are later resolved when the bones re-establish a normal anatomic relationship later in their growth. It is also possible that the distal

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.113  Grade V chondromalacia seen as pink exposed eburnated bone on the medial slope of the trochlear notch of the ulna at the bottom and on the medial ridge of the humeral condyle to the upper right. The telescope is looking craniolaterally from a medial portal with dorsal or proximal up and medial to the right. A free medial coronoid process fragment is visible in the background between the humeral condyle and the base of the medial coronoid process on the far right of the image. The humeral condyle cartilage shows mild glaciation to the left of the feathered bone-cartilage margin with irregular frayed cartilage margins around the ulnar lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.115  Glaciation on the radial head cartilage, in the center portion of the image, with Grade III severity in the presence of Grade V chondromalacia on the humeral condyle at the top of the picture and on the medial coronoid process joint surface in the lower right. Glaciation is also seen at the margin of the humeral condyle lesion. Proximal or dorsal is up, medial is to the right, and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.116  The appearance of what seems to be cartilage regrowth over Grade V chondromalacia seen as small islands of cartilage scattered over the eburnated bone of the humeral condyle wear lesion. Dorsal or proximal is to the upper left with medial to the right and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.114  An uncommon, roughened cartilage margin at the edge of a Grade V humeral condyle wear lesion. Humeral condyle fills the top of the picture with exposed bone in the foreground. Exposed bone is also seen on the ulna to the lower left and on the radial head to the lower right with frayed cartilage present between the two bones. The telescope is looking craniolaterally from a medial portal with dorsal or proximal up and medial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

physis of the humerus does not grow symmetrically with the medial and lateral portions growing at different rates at different times so that there are medial or lateral deviations of the bone during growth that remain or are corrected by the time of physeal closure. All joints where this has been seen have not had any previous surgery or intra-articular treatment and this appearance has not been seen in second look arthroscopies.

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Figure 4.117  A Grade V chondromalacia lesion on the ulnar articular surface seen with islands of cartilage scattered over the exposed eburnated bone. This appearance suggests cartilage regrowth. The ulnar articular surface fills the bottom left of the image with a band of irregular cartilage at radial-ulnar articulation and exposed bone on the radial head to the far right. The telescope is looking craniolaterally from a medial portal with the image rotated so that proximal or dorsal is to the right and medial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.118  The appearance of cartilage regrowth in Grade V lesions on both humeral and ulnar articular surfaces. The telescope is looking craniolaterally from a medial portal with the humeral condyle at the top of the picture, the ulnar articular surface at the bottom, and the radial head with glaciation wear lesions in the background to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Cartilage wear lesions with all levels of severity can also be seen without identifiable fixed or free coronoid process fragments (Figure  4.120). Fixed medial coronoid process fragments can be hidden from arthroscopic view by normal cartilage or by abnormal articular cartilage (Figure 4.121). Preoperative CT may reveal fissure lines or other abnormalities in the bone of the medial coronoid process providing an indication for partial or

Figure 4.119  A more uniform distribution of what appears to be cartilage regrowth over the exposed bone of a Grade V humeral condyle lesion. The medial ridge of the humeral condyle fills the top of the picture with medial coronoid process fragments visible at the bottom and in the lower right of the figure. The telescope is looking craniolaterally from a medial portal with proximal or dorsal up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.120  Medial coronoid process disease with Grade V chondromalacia on the medial coronoid process and on the medial ridge of the humeral condyle with no identifiable fixed or free coronoid process fragments. The telescope is looking cranially from a medial portal with dorsal or proximal up and medial to the right. Radial head is visible in the background to the left with ulna at the bottom and humeral condyle across the top. There is abnormal cartilage protruding from the ulnar side of the radial-ulnar articulation to the far left at the base of the coronoid process and to the right of center at the tip of the medial coronoid process. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

subtotal coronoidectomy in these cases and supporting cartilage removal to determine the presence or absence of fissure lines or fixed fragments. Without CT guidance indicating underlying bone pathology normal cartilage may be left in place. Abnormal cartilage on the medial coronoid process raises the question concerning the

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

need for cartilage removal to assess the underlying bone for lesions. CT is not sufficiently accurate to determine in all cases the presence or absence of medial coronoid process bone pathology that requires partial or subtotal coronoidectomy. Removal of abnormal cartilage is recommended to assess the underlying bone and may reveal fixed fragments or fissure lines that would otherwise be missed. Removal of the cartilage from a case such as that depicted in Figure 4.121 may reveal a fissure line defining a fixed medial coronoid process fragment (Figure 4.122). Medial coronoid process fragments are most commonly found in their site of origin as fixed fragments or free fragments that are movable but are not displaced. Many free fragments have some soft tissue attachments that tether them to their site of origin others are seen that do not have any attachment allowing them to move more freely (Figure 4.123) or be displaced from their site of origin. Many displaced fragments are found in the cranial compartment of the joint and can be small (Figure  4.124) or medium (Figure  4.125) to very large (Figure 4.126). In cases with a displaced fragment, the defect in the medial coronoid process where the fragment originated may be seen as an empty space (Figure  4.127) or more typically will be filled with fibrous tissue (Figure  4.125) or fibrocartilage (Figure 4.128). Rare loose displaced fragments are seen

Figure 4.121  Abnormal cartilage, Grade III chondromalacia exhibited as fibrillated cartilage on the lateral margin of the medial coronoid process in the lower right of the figure. A small free fragment is visible at the tip of the lateral margin of the medial coronoid process in the upper center background. No other indication of medial coronoid process abnormality was seen. Humeral condyle is at the top of the image with ulnar articular surface filling the lower left and a small portion of the radial head to the far right. Proximal or dorsal is up with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.122  A fissure line is seen as an indistinct slightly darker line in the medial coronoid process delineating a fixed coronoid process fragment with sclerotic bone in the fragment above the fissure line and normal bone in the portion of the coronoid process below the fissure line. The medial coronoid process and this fixed fragment were covered with normal cartilage but there was a visible demarcation line in the cartilage over the fissure line. Overlying cartilage has been removed with a shaver to expose the fissure line. Dorsal or proximal is up and medial is to the right with the telescope looking craniolateral from a medial portal. The medial coronoid process fills the image with a small area of radial head in the background and a sliver of humeral condyle at the very top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.123  A free medial coronoid process fragment that has no soft tissue tether and is totally free in the joint but is constrained by the surrounding bone that is keeping it from becoming displaced. Humeral condyle is at the top of the image, ulna at the bottom, the free fragment in the center, and the bone defect where the fragment originated is to the left. Proximal is up and medial to the left with the telescope looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

wedged (Figure 4.129) or free between the humeral condyle and ulna or radius (Figure 4.130). Arthroscopic surgical procedures performed for medial coronoid process disease depend on the lesions

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Figure 4.124  A small displaced medial coronoid process fragment seen in the cranial joint compartment by placing the telescope into the craniomedial operative portal and looking laterally. Proximal or dorsal is up. A small portion of the cranial margin of the radial head is seen at the bottom of the image with the fragment filling the center and reactive joint capsule is visible around the fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.125  A medium sized displaced medial coronoid process fragment is seen in the cranial joint compartment through the space between the medial coronoid process and humeral condyle with the telescope looking craniolaterally from a medial portal. The displaced fragment is seen in the background with a medial coronoid process osteophyte in front of the arthrolith. The humeral condyle articular surface is visible to the upper right, the radial head is seen in the background at the center right, the fixed portion of the medial coronoid process is across the bottom of the image with Grade III chondromalacia on its surface, and a large osteophyte is visible in the center deep to the fixed medial coronoid process but in front of the free fragment in the cranial joint compartment. A white area between the osteophyte and the fixed medial coronoid process is fibrous tissue with mild villus synovial reaction filling the defect created by displacement of the free fragment. Medial is to the left and dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.126  A very large displaced medial coronoid process fragment is seen in the cranial joint compartment through the space between the humeral condyle to the upper right and the radial head to the lower left. The free fragment completely fills the center of the picture obscuring visualization of the cranial compartment. The telescope looking craniolaterally from a medial telescope portal with dorsal or proximal to the upper right and medial to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.127  An empty defect in the lateral margin of the medial coronoid process left following displacement of a small free fragment. The fragment is visible in the background lateral to the tip of the fixed portion of the medial coronoid process. The telescope is looking cranially from a medial portal with dorsal up and medial is to the right. A small portion of the humeral condyle is visible in the upper left with Grade III chondromalacia, the fixed portion of the medial coronoid process with Grade V chondromalacia is filling the right side of the image, the radial head is to the left with Grade V chondromalacia to the far left, and a band of residual cartilage is present on the medial margin of the radial head that extends into the radial-ulnar articulation. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.128  A defect on the lateral margin of the medial coronoid process left by displacement of a free fragment that has been filled with fibrocartilage that appears like normal cartilage but is soft on palpation. The humeral condyle with Grade V chondromalacia fills the upper portion of the image with the fixed portion of the medial coronoid process across the bottom of the image. Medial is to the left with proximal or dorsal up and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.129  A free displaced medial coronoid process fragment, visible in the center of the picture, is wedged between the humeral condyle and the radial head. The humeral condyle is present in the upper left with glaciation type cartilage wear caused by the free fragment, a small portion of the radial head is visible to the left of the free fragment, the medial coronoid process to the lower right is obscured by fibrous tissue and synovitis. An instrument is seen in the lower far-right. The telescope is looking craniolaterally with medial to the right and proximal or dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.130  A free displaced medial coronoid process fragment that is loose in the joint space between the humeral condyle and the ulna. Humeral condyle fills the right side of the image with medial coronoid process to the left. The telescope is looking craniolaterally from a medial portal with the image rotated so that dorsal or proximal is to the right and medial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

present and vary from simple removal of a free fragment to extensive resection of the medial coronoid process and removal of osteophytes. Miner coronoid process pathology can be managed with hand instruments, but major resection procedures are facilitated with a power shaver. The VAPR bipolar radiofrequency unit is rarely used in the elbow but is indicated when there is villus synovial reaction that interferes with visualization (Videos 4.8 and 4.9). When the lesion or lesions have been identified a needle is placed into the joint at the operative portal site to confirm the best location for portal placement (Figure 4.6), a stab incision is made at this site with a no. 11 blade (Figure 4.7), and the operative portal is established using a curved mosquito hemostat to bluntly dissect into the joint (Figure  4.8). Coronoid process procedures are typically performed without an operative portal cannula, but one can be used if desired. Removal of small- to medium-sized free fragments is performed with hand instruments by grasping the loose fragment and removing it with arthroscopic rongeurs (Figure  4.131) (Video 4.10), arthroscopic grasping forceps (Video 4.11), or with the mosquito hemostat (Figure 4.132) used to establish the operative portal. If the free fragment is seated in the boney defect it may need to be elevated out of its bed with a curette (Figure 4.133), with a hook probe (Figure 4.134), with a mosquito hemostat (Figure  4.135) (Videos 4.2 and  4.4), or occasionally with arthroscopic rongeurs

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Figure 4.131  Removing a small free medial coronoid process fragment using 2.0mm arthroscopic rongeurs passed through a craniomedial operative portal. This instrument is delicate and is not used for biting into bone, but it is excellent for grasping small free fragments. The telescope is looking craniolaterally from a medial portal with proximal or dorsal up and medial to the right. Humeral condyle fills the top of the image with Grade V chondromalacia to the right and normal to Grade I chondromalacia to the left. Ulna is to the lower right with Grade V chondromalacia and radial head is visible between the two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.133  A free medial coronoid process fragment is being elevated out of the bone defect with a curette to make it accessible for removal. The curette is inserted through a craniomedial portal with the telescope looking craniolaterally from a medial portal. Proximal or dorsal is up with medial to the right. Humeral condyle is seen across the top of the image with the indistinct free fragment to the lower left and the curette positioned to catch and elevate the cranial margin of the fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.132  Removing a small free medial coronoid process fragment with the curved mosquito hemostat that was used to establish the operative portal. The instrument is inserted through a craniomedial operative portal and is grasping the free fragment. The telescope is looking craniolaterally from a medial portal with dorsal up and medial to the right. Humeral condyle is at the top of the image with normal cartilage, the medial coronoid process to the lower right with exposed bone, and an area of radial head with exposed bone is seen to the far left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.134  Elevating a free medial coronoid process fragment with a hook probe to make it accessible for removal. The hook probe is positioned against the cranial surface through a craniomedial portal. Proximal or dorsal is up with medial to the right and the telescope is looking craniolaterally from a medial portal. Humeral condyle is at the top of the image with the free fragment covered with cartilage and without any visible margins fills the lower half of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure  4.136) before removal. The elevated free fragment is then grasped with the hemostat, with arthroscopic grasping forceps (Video 4.11), or most commonly with arthroscopic rongeurs (Figures  4.137 and  4.138) (Video 4.10) for removal.

Small- and medium-sized fixed fragments are managed very much like free fragments but typically require more manipulation to achieve complete removal and sometimes require use of a shaver. Elevation of fixed fragments out of their site of origin requires more force

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.135  Elevating a small free medial coronoid process fragment out of its bed with a curved mosquito hemostat. Dorsal or proximal is up with medial to the left, the hemostat is inserted through a craniomedial portal, and the telescope is looking craniolaterally through a medial portal. A small portion of humeral condyle is seen at the top, medial coronoid process is to the left and bottom, and the fragment is partially elevated out of the site of origin on the lateral margin of the medial coronoid process. Humeral condyle and medial coronoid process cartilage appears normal with Grade I chondromalacia on the articular surface of the fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.136  Arthroscopic rongeurs are occasionally used to elevate a free fragment from its bed. The large free fragment fills the upper portion of the figure, a narrow sliver of humeral condyle is at the very top of the image, the medial coronoid process is at the bottom, and the rongeurs are inserted through a craniomedial portal into the line of fragment separation. Medial is to the right, proximal or dorsal is up, and the telescope is looking craniolaterally from a medial portal. Normal cartilage is present on all articular surfaces. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.137  Removing an elevated free medial coronoid process fragment using 3.5mm Blakesley rongeurs. Proximal or dorsal is up with medial to the right, the telescope is looking craniolaterally from a medial portal, and the rongeurs are inserted through a craniomedial portal. Humeral condyle is to the upper left, redial head is to the left and bottom, and the ulna is beyond the lower right margin of the image. The fragment is fully enclosed in the rongeurs to allow removal in one piece. Care is taken with the rongeurs in this position to avoid biting into the humeral condyle with the cranial jaw that cannot be seen. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.138  Removing the elevated free medial coronoid process fragment seen in Figure 4.136 using 3.5mm Blakesley rongeurs. Rongeurs work well for removing larger fragments as seen here because their sharp edge achieves good purchase and if too much pressure is applied a bite is taken out of the free fragment. Grasping forceps used in this situation have a tendency to crush the fragment creating multiple small bone fragments that require removal of each individual piece. The instrument is inserted through a craniomedial portal with the telescope looking craniolaterally from a medial portal. Dorsal or proximal is up and medial is to the right. A small portion of humeral condyle is seen at the top of the figure with medial coronoid process at the bottom and the fragment filling the space between the two bones to the left of the instrument jaw. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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than when elevating free fragments and is achieved most easily with a curette (Figures  4.139 and  4.140) (Video 4.12) but other instruments are used when needed. Fixed fragments will occasionally elevate as one piece but much more frequently are broken away from the parent bone in fragments (Video 4.12). As free pieces of bone are created, they are removed before creating more free pieces (Figure 4.141) (Videos 4.12 and 4.13) using the same instruments as for removal of free fragments. Elevation of the remaining portion of a fixed fragment is done most commonly with a curette using the same starting position and direction of force as the initial elevation (Figure 4.142). Bone can also be freed by directing the curette from the articular surface on the cranial aspect of the remaining fixed bone and applying caudally directed force (Figure  4.143) (Video 4.14) or placing the curette on the lateral margin of the bone and applying medially directed force (Figure  4.144). Instrumentation other than a curette is used for elevation and removal of additional fixed fragment bone when indicated. The 70° microfracture chisel works

Figure 4.139  Elevation of a fixed medial coronoid process fragment with a curette by placing the curette cranial to the fragment and applying caudal force. The medial margin of the fixed fragment can be seen as a very subtle line in the cartilage that is whiter than the surrounding cartilage and is slightly raised. The telescope is looking craniolaterally from a medial portal, the instrument is inserted through a craniomedial operative portal, dorsal or proximal is to the upper left and medial is to the lower left. Medial coronoid process is to the lower right, the fixed fragment extends from the curette to the upper right, radial head is in the background to the upper right, humeral condyle is to the upper left, and the blurred medial collateral ligament is to the far left behind the curette. There is normal cartilage on all surfaces except there the fissure line change is seen. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.140  The effect of elevation of the fixed fragment seen in Figure 4.139 as pressure was applied in a caudal direction with the curette. Visible structures and orientation are the same as in the previous figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.141  Free pieces of bone created by elevating a fixed medial coronoid process fragment. The loose pieces are removed as created prior to elevating more bone. The instrument is inserted through a craniomedial portal, the telescope is looking craniolaterally from a medial portal, dorsal is up and medial is to the right. Humeral condyle extends across the top of the image with medial coronoid process at the bottom. Radial head is to the left in the background and craniomedial joint capsule is to the right behind the forceps. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

well for elevation of small superficial residual bone (Figure 4.145), arthroscopic rongeurs are used for elevation and removal of soft residual bone (Figure  4.146), and the shaver is also used when indicated (Figures 4.61 and Figure 4.122) (Video 4.15).

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.142  Elevation of residual fixed medial coronoid process bone using a curette placed cranial to the bone to be elevated and with pressure applied in a caudal direction. Applying pressure in a caudal direction minimizes the chance of bone fragments being lost in the cranial compartment. Proximal or dorsal is up, medial is to the right, the curette is inserted through a craniomedial portal, and the telescope is looking craniolaterally from a medial portal. Medial coronoid process is at the bottom and lower left with humeral condyle at the top and radial head is in the background to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.144  Elevation of residual medial coronoid process bone from the deep lateral margin of the fixed fragment using a curved curette placed lateral to the bone with application of medially directed pressure. Lateral margin fragments often extend deeply into the articulation of the radius and ulna. Dorsal or proximal is up on the image, medial is to the right, the instrument is inserted through a craniomedial portal, and the telescope is looking craniolaterally from a medial portal. Medial coronoid process fills the bottom of the image with radial head indistinctly seen to the upper left in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.143  Elevation of residual fixed medial coronoid process bone using a curved curette placed on the far side of the fixed fragment with pressure applied caudally and distally. In this image dorsal or proximal is up, medial is to the left, the curette is inserted through a craniomedial operative portal into the joint space, and the telescope is looking craniolaterally from a medial portal. Humeral condyle is at the top behind the curette and medial coronoid process is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.145  Elevation of a small portion of residual bone from the caudal end of a fixed medial coronoid process fragment using the 70-degree microfracture chisel. The telescope is looking craniolaterally from a medial portal with craniomedial to the left and proximal or dorsal up on the image. The medial coronoid process is at the bottom, humeral condyle is across the top of the image, and the remaining portion of the fixed fragment is to the right of the tip of the instrument with slightly whiter cartilage than the medial coronoid process. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.146  Two-millimeter arthroscopic rongeurs are being used to remove a small piece of deep residual soft bone remaining after partial removal of a fixed medial coronoid process fragment. The telescope is looking craniolaterally from a medial portal, the instrument is inserted through a craniomedial portal, dorsal or proximal is up, and medial it to the right. Medial coronoid process cartilage is seen at the bottom with exposed bone of the fixed fragment filling the remainder of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Lateral margin fixed fragments frequently extend a significant distance distally in the articulation between the radial head and the ulna. Residual abnormal bone is commonly found in the deep portion of the bony defect created by removal of fixed medial coronary process fragments. This bone is typically soft and friable with variably visible fissure lines and variable difference from the normal, sclerotic, or soft bone comprising the remaining fixed portion of the medial coronoid process (Figures 4.147 and 4.148). The residual fixed fragment bone can also be sclerotic (Figure  4.149). The narrow space between the radial head and the stable portion of the medial coronoid process prevents access with most instruments making the 70° microfracture chisel ideal for debriding residual bone from the deep remnants of fixed fragments (Figures 4.150 and 4.151). Irrigation is used to remove the debris created by this process (Figure 4.152). Elevation of deep residual sclerotic bone will occasionally produce a defined fragment (Figure 4.153) that is removed with rongeurs or grasping forceps. When elevating medial coronoid process fragments, it is advisable to always place the elevating instrument cranial to the fragment and apply caudally directed force to move the freed bone caudally (Figures 4.133–4.136, 4.139, 4.140, and 4.142) (Videos 4.12–4.14). This moves the fragment caudally away from the cranial compartment

Figure 4.147  Residual fixed coronoid process fragment bone in the depth of the articulation between the radial head and medial coronoid process that has been exposed by removal of the superficial portion of the fixed fragment. There is an indistinct fissure line between the sclerotic, smooth avascular, bone of the medial coronoid process on the right side of the image and friable, irregular, bleeding, bone of the fixed fragment in the center of the image. The smooth white surface on the left side of the image is the medial margin of the radial head. Proximal is up, medial is to the right, the telescope is looking craniolaterally from a medial portal, and the shaver is inserted through a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.148  Deep residual friable bone on the lateral margin of the medial coronoid process after removal of the superficial portion of a fixed fragment. There is a clear demarcation line between the friable fixed fragment bone on the left side of the medial coronoid process and normal bone on the right side of the image. The smooth white surface on the left side of the image is the medial margin of the radial head. A curved microfracture chisel is seen to the upper right of the image. This instrument works well for freeing fixed fragment bone in the narrow space deep in these lesions. The chisel is inserted through a craniomedial portal, dorsal or proximal is up, medial is to the right, and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.149  Deep residual sclerotic bone after removal of the superficial portion of a fixed fragment using a shaver. A clear demarcation line or fissure is visible as a whiter line with dense avascular sclerotic bone on both medial and lateral sides of the fissure line. The shaver inserted through a craniomedial operative portal is seen at the top of the image with medial coronoid process to the lower right, humeral condyle to the upper left, radial head to the left, and the radial-ulnar articulation seen as a line of ragged white tissue extending from the tip of the shaver to the lower left. The telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.150  A 70-degree microfracture chisel is being used to remove residual friable bone from the lateral margin of the medial coronoid process in the deep bone defect seen in Figure 4.147 after removal of the superficial portion of a fixed medial coronoid process fragment with the shaver. The narrow sharp tip of the microfracture chisel and the 70-degree angle make this instrument ideal for accessing this space. Proximal is up, lateral is to the left, the chisel is inserted through a craniomedial portal, and the telescope is looking craniomedially from a medial portal. Exposed bone of the medial coronoid process is seen across the bottom of the image with the medial margin articular cartilage of the radial head to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.151  Completion of removal of deep friable bone from the elbow seen in Figure 4.148. For comparison, the ridge of the bone on the right side of the image is the level of the bone visible in Figure 4.148. The medial margin of the radial head is seen filling the left side of this figure with medial coronoid process to the right and the telescope is looking craniolaterally from a medial portal. Proximal or dorsal is up and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.152  Irrigation with an egress cannula or operating portal cannula is used to remove debris following elevation of friable bone with the microfracture chisel. This is the same elbow as seen in Figures 4.147, 4.148, 4.149, 4.150, and 4.151. Orientation and visible structures are the same as the previous listed figures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figures 4.137, 4.138, and 4.141) decreasing the chance of losing freed bone into the cranial compartment (Figure 4.154). Removal of bone fragments that are lost into the cranial compartment is difficult causing significantly longer operating times but can, in most cases, be achieved through the standard medial operative portals.

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remove the fragment in multiple pieces. Rongeurs are used for this technique (Figures 4.155 and 4.156) because they achieve a better grip than most grasping instruments and if the fragment does not come out as one piece, then rongeurs remove a piece of the fragment

Figure 4.153  Elevation of deep fixed fragment sclerotic bone from the radial head articulation with the ulna will occasionally produce a defined fragment that is removed with rongeurs or grasping forceps. The radial head is visible on the left with the fixed portion of the medial coronoid process on the right. The tip of an instrument is seen in the lower right that is inserted through a craniomedial operative portal. The telescope is looking craniolaterally from a medial portal with dorsal or proximal up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.155  Blakesley 3.5 mm arthroscopic rongeurs being used to grasp a large free medial coronoid process fragment for removal. Note the position of the rongeurs with the jaws parallel to the joint space. To avoid damage to the humeral condyle cartilage the rongeurs are rotated before or during closure. Medial is to the left with the instrument inserted through a craniomedial operative portal, dorsal or proximal is up, and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.154  A medial coronoid process fragment that was displaced into the cranial compartment during manipulation for removal. The fragment is visible in the upper right of the image with the cranial margin of the radial head on the left and the tip of the medial coronoid process is at the bottom of the image. The telescope has been inserted into the craniomedial operative portal and is looking laterally with cranial to the right and proximal or dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

If removal through these portals is not possible, then the telescope is moved to the craniomedial operative portal and a craniolateral operative portal is established. Large medial coronoid process fragments are most commonly free fragments and are seen with all degrees of chondromalacia (Figures  4.42–4.44, and  4.75). To extract large free fragments, it may be necessary to

Figure 4.156  The 3.5 mm Blakesley rongeurs with a tight grip on the free fragment after rotation described in Figure 4.155. The upper jaw of the rongeurs is visible and the lower jaw is hidden behind the free fragment. The telescope is looking craniolaterally from a medial portal, the instrument is inserted through a craniomedial portal, dorsal is up and medial is to the left. Humeral condyle is at the top, medial coronoid process at the bottom, and radial head is seen to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

rather than shattering the fragment (Figure  4.157). When using rongeurs to remove free bone fragments from the medial compartment of the elbow, it is important to position the jaws of the instrument so that cartilage on the humeral condyle is not damaged. The limited space between the medial ridge of the humeral condyle and the medial coronoid process restricts manipulation of the rongeurs. The jaws are most easily opened parallel to the joint space (Figure 4.155) which is acceptable for instrument positioning, but risks damage the humeral condyle cartilage when the jaws are closed. To prevent removing humeral condyle cartilage, the rongeurs are rotated away from the parallel position before the jaws are closed (Figure  4.156). Large fragments can also be reduced in size with a shaver before removal (Figures  4.158–4.160) but this is sometimes difficult if the fragment is mobile preventing effective shaver purchase. Removal of large fragments (Figure 4.161) is also facilitated by removal of the fixed abaxial portion of the medial coronoid process between the operative portal and the free fragment (Figure  4.162) creating a larger operating space (Figure  4.163) for removal of the free fragment (Figure 4.164). Most cases with large free fragments will have sufficient pathology of the fixed portion of the medial coronoid process to require a subtotal

Figure 4.158  Using the arthroscopic shaver with a 3.5 mm burr to remove part of the fixed medial coronoid process to allow access to a large free fragment before using the shaver to reduce the size of a free fragment. Medial is to the right, proximal or dorsal is up, the shaver is inserted through a craniomedial operative portal, and the telescope is looking craniolaterally from a medial portal. The free fragment fills the upper left of the image with fixed medial coronoid process to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.159  Removing part of the large free fragment seen in the previous figure with the arthroscopic shaver using a 3.5 mm burr after the fixed portion of the medial coronoid process has been removed sufficiently to allow access to the free fragment. Orientation is the same as the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.157  The free fragment seen in Figures 4.155 and 4.156 after the first attempt at removal with rongeurs. A portion of the left or medial side of the fragment was removed with the rongeurs taking a clean bite, seen as exposed bone, and leaving the remainder of the free fragment intact. Dorsal, or proximal, is up on the image and medial is to the left. Humeral condyle cartilage is visible across the top of the image with the fixed portion of the medial coronoid process at the bottom. The telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

c­ oronoidectomy which is done before removal of the free fragment rather than after. Partial or subtotal medial coronoidectomy is performed when needed for removal of large medial coronoid process fragments (Video 4.15), when there is Grade V chondromalacia involving the medial coronoid process (Video 4.16), and when there is abnormal bone in the medial coronoid process (Video 4.17). Cartilage wear lesions are caused by excessive pressure on the cartilage secondary to “incongruity” of the medial coronoid process that is

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Figure 4.160  In this image the free fragment from the last two figures has been reduced in size with the shaver to a small amount of overlying cartilage and small fragments of bone adjacent to the medial margin of the radial head. Hand instruments and irrigation are used to complete the procedure. Orientation is the same as in the previous two figures. The remainder of the free fragment fills the left and lower left of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.161  A large free medial coronoid process fragment that is too large to be removed in one piece through the joint space between the humeral condyle and the fixed portion of the medial coronoid process. The free fragment is seen extending from the right side of the image across the middle to just past the center. Proximal is up on the image and medial is to the right with the telescope looking craniolaterally from a medial portal. The humeral condyle is at the top and the fixed portion of the medial coronoid process is at the bottom of the image. The needle visible on the right side is placed in preparation for placement of an operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

either positioned higher or more proximal than the radial head, due to the semilunar notch being smaller than the medial ridge of the humeral condyle, or to other as yet undetermined factors (Barthélémy et al. 2014; Coggeshall et  al.  2014; Coppieters et  al.  2015; Mariee et  al.  2014;

Figure 4.162  The arthroscopic shaver with a 3.5 mm burr is being used to remove the fixed portion of the medial coronoid process to create space to allow removal of the free fragment in one piece. This is the same joint as seen in Figure 4.161 with the same orientation and telescope position. The shaver is inserted through a craniomedial operative portal between the humeral condyle at the top and the fixed portion of the medial coronoid process at the bottom. The free fragment is hidden behind the shaver. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.163  Following removal of the fixed portion of the medial coronoid process seen in Figures 4.161 and 4.162 there is adequate space between the humeral condyle and the remaining portion of the medial coronoid process to remove the free medial coronoid process fragment in one piece. The ragged medial surface of the free fragment is visible extending across the middle of the image with the humeral condyle at the top, the defect created by partial coronoidectomy in the lower right, and the medial collateral ligament obliquely crossing the right center. The telescope is looking craniolaterally from a medial portal with up proximal or dorsal and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.164  The completed procedure seen in Figures 4.161, 4.162, and 4.163 after removal of the free fragment and after irrigation to remove debris. Orientation and visible structures is the same as seen in the previous three figures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Meyer-Lindenberg et al. 2002a; Samoy et al. 2006; Samoy et al. 2012; Samoy and de Bakker 2013; Van Ryssen and van Bree 1997). The pattern of the wear lesion defines the pattern of excessive pressure and where bone is removed for coronoid process revision. Sufficient bone is removed from the involved portion of the coronoid process to eliminate contact with the humeral articular surface over the area of excessive pressure. When well defined, the area of exposed eburnated bone, Grade V chondromalacia (Figures 4.40, 4.112, 4.120, and 4.165), is removed including the feathered margin of worn cartilage to the level of normal cartilage (Figure 4.166). Minor coronoid process revision also can be performed with hand instruments using a curette to loosen pieces of bone and then removing the loose pieces with rongeurs or grasping forceps as was shown for removal of fixed medial coronoid process fragments (Video 4.18). Hand instruments work well for removing soft osteoporotic bone but removal of sclerotic bone is greatly facilitated with a power shaver. The revision is done to the coronoid process on the ulnar side of the joint and bone is not removed from the humeral condyle. The power shaver is used with great care as it has the potential of causing extensive damage to the joint or to the telescope if improperly used. Shaver controls allow it to be rotated in either direction or with oscillating rotation. For removing bone, a burr blade is used with unidirectional rotation. Burrs are designed with blades that cut better in one direction than the other (Figure 4.167) with counterclockwise rotation, producing more aggressive cutting action and clockwise rotation produces less-aggressive cutting (Figure  4.166) but produces adequate bone

Figure 4.165  A well-defined area of Grade V chondromalacia on the medial coronoid process in an elbow with a large free medial coronoid process fragment. Medial is to the left with proximal or dorsal up and the telescope is looking craniolaterally from a medial portal. The area of “incongruity” where the coronoid process is too high is defined by the area of cartilage loss where the load on the cartilage is too great seen across the lower center of the image. The cartilage margin is feathered to normal thickness cartilage where there is normal weightbearing at the bottom of the figure. Cartilage is also removed by the excess load from the area of the humeral condyle, at the top of the picture, that moves across the elevated area of the medial coronoid process. Note that the free fragment in the center has normal cartilage on its articular surface indicating that the load on its surface is within normal limits. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.166  Using the power shaver to perform a subtotal coronoidectomy. Bone is removed from the area of cartilage loss to drop the level of the coronoid process to the point where there is normal cartilage. In this right elbow the shaver blade is run in a clockwise direction to pull the blade away from the telescope. Medial is to the left, dorsal or proximal is up, the shaver is inserted through a craniomedial portal, and the telescope is looking craniolaterally from a medial portal. The medial coronoid process fills the lower right of the image and the medial surface of the radial head is seen to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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removal. It is recommended that the direction of blade rotation be used that pulls the blade away from the telescope to reduce the chance of telescope damage with the shaver. Figure 4.167 shows the burr in a left elbow joint and to run the blade so that it is pulled away from the telescope, it is run in the counterclockwise direction. Figure 4.166 shows the burr in the right elbow joint and to run the blade so that it is pulled away from the telescope, it is run in the clockwise direction. Coronoid process revision or removal is performed for Grade V chondromalacia as well as for free or fixed coronoid process fragments with abnormal bone in the fixed portion of the medial coronoid process, seen on CT images or at the time or arthroscopy, even in the presence of lesser grades of chondromalacia. Free fragments are present with normal, osteoporotic or sclerotic bone in the fixed portion of the medial coronoid process. Subtotal coronoidectomy in cases with abnormal bone includes removal of all the abnormal bone in addition to removal of the free fragment. Fixed fragments are seen as medial coronoid process fissure lines with sclerosis or osteoporosis of the fixed fragment and with normal bone, sclerosis, or osteoporosis of the coronoid process medial to the fissure line. These lesions when first examined can appear as normal cartilage on the coronoid process (Figure 4.56), normal cartilage with cartilage lines defining the fragments (Figures 4.48–4.52, 4.54, and 4.55), as roughened cartilage (Figures 4.57 and 4.58), or as fissure

Figure 4.167  A power shaver with a 3.5 mm burr is being used to perform a subtotal coronoidectomy. In this left elbow joint the shaver blade is run in a counterclockwise direction to pull the blade away from the telescope. Medial is to the right, dorsal or proximal is up, the telescope is looking craniolaterally from a medial portal, and the shaver is inserted through a craniomedial portal. The medial coronoid process with exposed bone fills the bottom of the figure with the medial surface of the radial head to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

lines in exposed bone (Figures 4.59 and 4.60). Normal or abnormal cartilage is removed for evaluation of the underlying bone (Figures 4.61 and 4.122). Bone lateral to the fissure line, the fixed fragment, is removed with any abnormal bone abaxial or medial to the fissure lines. This is performed most easily with a power shaver but can be accomplished with hand instruments. Cartilage appearance does not provide accurate information about the condition of underlying bone. Free fragments that have migrated into the cranial compartment of the joint (Figures  4.124–4.126) are removed. In most cases, exploration of the cranial ­compartment and fragment removal can be accomplished through the standard medial portals. Removal of medial coronoid process fragments or partial coronoidectomy facilitates access to the cranial compartment through the medial portals. Free cranial compartment fragments are moved into the medial joint space using a curved curette or a hook probe and are then removed from the joint with rongeurs, grasping forceps, or a curved mosquito hemostat. Direct removal of free fragments from the cranial compartment can also be done using rongeurs (Figure 4.168), a curved mosquito hemostat (Figure 4.169), or grasping forceps but this is more difficult and many times the fragment is pushed laterally out of reach. Removal of part of the fixed portion of the

Figure 4.168  Rongeurs are being used to remove a free medial coronoid process fragment from the cranial compartment of the joint. The rongeurs are visible on the right side of the image with the free fragment in the center, the tip of the medial coronoid process is to the lower left, and reactive joint capsule is on the left side. Cranial is to the right, dorsal or proximal is up on the image, and the rongeurs are inserted through a craniomedial portal. The telescope is inserted through a medial portal to look laterally after being passed between the humeral condyle and the remnant of the medial coronoid process after a subtotal coronoidectomy. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.169  Curved mosquito hemostats are being used to explore the cranial joint space for removal of a displaced free medial coronoid process fragment. Cranial is to the right and proximal or dorsal is up on the image. The telescope is in the craniomedial operative portal and the hemostat is in the medial telescope portal. There is marked villus synovitis in this joint obscuring clear visualization. Humeral condyle is seen to the left with the free fragment to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

medial coronoid process may be required to allow access into the cranial compartment from the standard medial portals. This approach is also used for retrieving medial compartment fragments that are lost into the cranial compartment during removal procedures. Care is used during removal of coronoid process fragments and revision of the coronoid process with hand instruments to prevent loss of fragments into the cranial compartment. This error greatly increases the difficulty of the procedure and operative time involved. If lost fragments cannot be accessed through the standard medial portals additional portals are established as needed until removal is achieved. The craniomedial operative portal can be used for a telescope portal to provide visualization of the cranial compartment to find residual fragments and ensure that all fragments have been removed (Figure 4.170). Addition of a cranial or craniolateral operative portal for fragment removal can be added if needed. After coronoid process fragments have been removed, the bone defect created by removal is debrided. This may be a simple procedure in some cases accomplished with irrigation (Figures  4.152 and  4.164) but can also require use of a curved curette (Figure 4.144) or a 70° microfracture chisel (Figure  4.150). The microfracture chisel is ideally suited for this procedure as its sharp tip fits easily into the narrow cleft between the radius and ulna to remove bone fragments. Osteophytes commonly form with medial coronoid process disease and in severe cases become large enough to interfere with joint motion. Joint flexion is impaired

Figure 4.170  The cranial joint compartment visualized with the telescope in the craniomedial operative portal after removal of a cranial compartment fragment. There are marked synovial villus reaction obscuring identification of anatomic structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

when there are large osteophytes on the dorsal margin of the radial head and joint extension is prevented by large anconeal process osteophytes (Figure  4.171). These large osteophytes are removed to improve the range of joint motion. Small osteophytes (Figure 4.172) that do not interfere with joint motion are left in place. Osteophyte removal greatly increases the complexity of elbow joint arthroscopy and prolongs procedure time. Interference with joint flexion by radial head osteophytes is much more common than anconeal process osteophytes interfering with extension but interference with extension is more debilitating than interference with flexion. Removal of radial head osteophytes (Video 4.19) is performed through the two standard medial joint portals whenever possible. Access to the cranial joint space through these portals typically requires removal of the medial coronoid process but this is not always necessary. Removal of large free medial coronoid process fragments sometimes provides sufficient space for access to dorsal radial head osteophytes. After removal of the free fragment and the medial coronoid process, if indicated, there is room for the telescope to pass through the resulting defect (Figure 4.173) into the cranial joint compartment (Figure 4.174). This approach is attempted first before placement of additional portals to decrease the number of portals required eliminating the need for establishing the more difficult cranial portals. In cases where this portal does not provide adequate access to the cranial compartment, the telescope is moved to the craniomedial operative portal (Figure 4.175). Once the telescope is positioned with a view of the cranial

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Figure 4.171  A lateral elbow Xray image showing large radial head and anconeal process osteophytes that require removal to improve elbow joint range of motion. The black lines indicate where bone should end in a normal joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.173  Removal of large medial coronoid process fragments and the medial coronoid process, if indicated, can provide access to the cranial joint compartment from a medial portal. A free medial coronoid process fragment has been removed from this elbow and a partial medial coronoidectomy has been performed to provide access to the cranial joint compartment. Cranial is to the right and proximal or dorsal is up on this image with the telescope looking laterally from a medial portal. A small portion of humeral condyle is visible at the top of the picture with the radial head to the left, joint capsule to the right, and the medial coronoid process excision site at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.172  A lateral Xray image of the contralateral, near normal, elbow of the patient in Figure 4.171 showing a very small radial head osteophyte and no visible anconeal process osteophyte. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

compartment derotation of the antebrachium facilitates examination of this joint space and removal of osteophytes on the dorsal margin of the radial head. Osteophyte configuration varies greatly from a smooth even ridge (Figure  4.176), to sharp-pointed projections (Figure 4.177), and large irregular rounded masses (Figure 4.178). A power shaver with a burr blade (Figure  4.179) or hand instruments (Figure  4.180) are used to removed dorsal radial head osteophytes. Curved shaver blades are available that facilitate this procedure. Both the power shaver and hand instruments are needed in some cases for complete osteophyte removal (Figure 4.181). Removal of the lateral portion of radial head osteophytes becomes more difficult due to interference of instrumentation with visualization

Figure 4.174  The cranial joint compartment viewed by passing the telescope through the space provided by removal of a large medial coronoid process fragment and partial removal of the medial coronoid process. Cranial is to the right with dorsal or proximal up. The humeral condyle is seen on the left with the lateral extent of the cranial joint space in front of the telescope and on the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure  4.182) and retraction of instrumentation is needed to monitor the progress of osteophyte removal (Figure 4.183). Hand instruments are also used to complete removal of the lateral portion of radial head

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.175  The cranial joint compartment viewed by passing the telescope through the craniomedial operative portal. Cranial is to the right and proximal or dorsal is up on the image. The craniodorsal extent of the humeral condyle is clearly visible on the left with the medial ridge in the foreground, lateral ridge in the background, and the sulcus is visible between the two ridges. The cranial joint capsule is distended across the dorsal and right sides of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.176  A smooth even ridge osteophyte on the dorsal margin of the radial head. Cranial is to the left. A small portion of the humeral condyle is visible at the top of the figure with the radial head osteophyte filling the lower right and villus synovial reaction seen in the background to the upper left. The telescope is looking laterally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­ steophytes and to improve examination of the cranioo lateral joint space for residual debris (Figure 4.184). An irrigation cannula is used to remove residual debris and can also assist exploration of the lateral extent of the cranial joint space (Figure  4.185). Visualization of the

Figure 4.177  A sharp pointed osteophyte on the dorsal margin of the radial head. Cranial is to the right with proximal up and the telescope is looking laterally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.178  A large blunt irregular osteophyte on dorsal margin of the radial head. Cranial is to the left with dorsal up. The humeral condyle is visible filling the upper right portion of the picture with the radial head osteophyte in the background deep to the sulcus of the humeral condyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

lateral portion of the cranial joint compartment can be improved by moving the telescope to the craniomedial operative portal (Figure 4.186). If access from the medial portals is not adequate, a craniolateral operative portal (Figures 4.3 and 4.4) can be used for removal of lateral osteophytes or free fragments in the cranial joint space while using the craniomedial operative portal for the telescope or a proximal cranial telescope portal can be established.

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Figure 4.179  Removing a radial head osteophyte using a power shaver with a 3.5mm burr blade inserted through a craniomedial operative portal. Cranial is to the right with proximal or dorsal up and the telescope is looking craniolaterally from a medial portal. A small portion of the humeral condyle is visible in the upper left with the radial head in the lower left and the ridge of osteophyte is extending across the right perimeter of the radial head. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.180  Using a curette to remove a radial head osteophyte. Bone fragments created with this technique are either pulled into the medial joint space for removal or are grasped and removed from the cranial joint compartment. Cranial is to the right with dorsal or proximal up. The curette is passed through a craniomedial operative portal and the telescope is looking craniolaterally from a medial portal. The humeral condyle is at the upper left, a small sliver of the medial coronoid process is visible at the bottom with the radial-ulnar joint space above that and the radial head filling the left center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Examination of osteophytes on the anconeal process is possible in some cases from the medial telescope portal (Figures 4.187 and 4.188). Access to osteophytes on the caudal aspect of the anconeal process for removal is through caudal portals on the medial and lateral sides of

Figure 4.181  The dorsal radial head osteophyte in this image has been partially removed with the power shaver. The remainder of the osteophyte adjacent to the humeral condyle cartilage was removed with hand instruments to decrease the chance of humeral condyle cartilage damage. A small portion of humeral condyle is present on the upper left side of the image with the osteophyte in the center and frayed joint capsule on the right. Cranial is to the right with proximal up. The telescope is looking laterally from a craniomedial operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.182  Removal of the lateral extent of radial head osteophytes becomes difficult due to interference of instrumentation with visualization. The shaver blade is on the right in this image and is partially obscuring observation of osteophyte removal. Cranial is to the right with proximal or dorsal up. The cranial surface of the humeral condyle is visible on the left with the radial head at the bottom and residual osteophyte is seen in the background between the shaver and the humeral condyle. Moving the shaver to the left to contact the residual osteophyte blocks clear visualization of the operative site. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.183  The shaver blade has been retracted to improve visualization and allow monitoring of the progress of osteophyte removal. The remaining osteophyte seen here is at the far lateral extent of the radial head. Cranial is to the right with dorsal or proximal up. A small portion of humeral condyle is visible on the left with the cut edge of radial head articular cartilage at the bottom in the foreground, exposed bone of the osteophyte resection site in the lower right, and frayed joint capsule is to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.184  A curved curette is being used to assist removal of the lateral portion of a radial head osteophyte and to explore for residual debris. Cranial is to the left with proximal or dorsal up. Humeral condyle is on the right with the dorsal margin of the radial head at the bottom center, and joint capsule is to the left. The telescope is looking laterally from a medial telescope portal and the curette is inserted through a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the triceps tendon (Figures 4.2, 4.3, and 4.5) shown as the egress portal sites in these figures. Synovial villus reaction in the caudal compartment commonly interferes with visualization and, if indicated, is removed using radiofrequency ablation before osteophyte

Figure 4.185  An irrigation cannula, seen in the upper right corner of the image, is positioned in the cranial joint space to remove residual debris and to assist examination of the lateral extent of the joint. Cranial is to the right, dorsal or proximal is up, humeral condyle is on the left, the dorsal margin of the radial head osteophyte resection is at the bottom, reactive joint capsule is to the right, and a small debris fragment is at the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.186  Completed removal of a dorsal radial head osteophyte is examined with the telescope in the craniomedial operative portal for a final check of completeness of osteophyte excision and debris evacuation. Cranial is to the left with proximal or dorsal up, a narrow sliver of humeral condyle is visible on the right, the dorsal margin of the radial head with the osteophyte resection site is at the bottom, and joint capsule is to the left and to the top of the visual field. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

removal (Figure 4.189). Osteophytes form on the caudal surface of the anconeal process (Video 4.20) and can extend proximally beyond the dorsal tip of the process (Figures  4.190 and  4.191). Hand instruments can be

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Figure 4.187  An osteophyte is visible on the tip of the anconeal process seen with the telescope looking caudolaterally from the standard medial portal. The image is obliqued so that dorsal or proximal is to the upper right and medial is to the upper left. Anconeal process fills the lower left of the image with the osteophyte seen as roughened cartilage surface at the upper extent of visible anconeal process. Humeral condyle wraps around the anconeal process from the top of the picture to the right and to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.188  An osteophyte on the caudal surface of the anconeal process is visible from cranially with the telescope in the standard medial portal. Dorsal or proximal is up and medial is to the left. The anconeal process is in the lower right of the image with humeral condyle articular surface across the top and the osteophyte is seen as the projection off the tip of the anconeal process with a stippled hyperemic surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

used for osteophyte removal but a power shaver with a burr blade is preferable (Figures 4.192 and 4.193). When all areas of the joint have been treated, the joint is irrigated thoroughly through all portals to ensure removal of debris and that there are no significant remaining osteophytes or free fragments. Abnormal cartilage is occasionally seen on the lateral coronoid process most commonly secondary to medial coronoid process pathology (Figures  4.101 and  4.105).

Figure 4.189  Villus synovial reaction that interferes with visibility commonly occurs in the caudal joint compartment of patients with anconeal process osteophytes and removal of this proliferative tissue is required prior to anconeal process osteophyte excision. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.190  A CT image showing osteophytes extending beyond the dorsal tip of the anconeal process. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Primary lateral coronoid process pathology is rare with loose fragments (Figure  4.194) or malformation with soft bone (Figure 4.195) being the most common findings. Assessment of suspected loose fragments, when instability of the fragment is not obvious (Figure 4.196), uses a hook probe passed from the standard craniomedial operative portal to apply pressure to the lateral coronoid process (Figure 4.197). These lesions are managed by removal of the loose fragments or abnormal bone. Visual access to the lateral coronoid process can be achieved through the standard medial telescope portal

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.191  Osteophytes on the caudal surface of the anconeal process seen from a caudal portal in an elbow with medial coronoid process disease. Proximal or dorsal is up with caudal to the right. The anconeal process filling the lower left center of the image and anconeal fossa cartilage is seen across the top in the background. The anconeal process osteophyte is present deep and to the right of the anconeal process. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.194  A loose lateral coronoid process fragment seen as primary pathology of the lateral coronoid process. The telescope is looking laterally through the joint from a medial portal with dorsal or proximal up and cranial to the right. The lateral ridge of the humeral condyle is at the top, the ulnar articular surface is at the bottom, a small portion of the radial head is to the right and the abnormal lateral coronoid process is in the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.192  Removal of the caudal anconeal process osteophytes seen in Figure 4.191 using the power shaver with a 3.5 mm burr blade. Visible structures and orientation are the same as in the previous figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.195  A small malformed lateral coronoid process comprised of soft friable bone is seen in the center background of the image. Cranial is to the left with proximal up. The telescope is looking laterally from a medial telescope portal with humeral condyle at the top, radial head to the left, ulnar articular surface in the bottom foreground, and lateral joint capsule is in the background to the right of center. A small iatrogenic cartilage fragment is seen to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.193  Successful removal of the caudal anconeal process osteophytes seen in Figures 4.191 and 4.192. Visible structures and orientation are the same as in the previous figures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

in most cases but typically a lateral operative portal is required, and visualization may require a lateral or caudolateral telescope portal. Hand instruments are typically used for removal of lateral coronoid process lesions. A curette is used to mobilize diseased bone

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Figure 4.196  An abnormal lateral coronoid process with a suspected fissure line through the area devoid of cartilage. Palpation confirmed that the lateral coronoid process was unstable. Dorsal or proximal is up with cranial to the left. Humeral condyle is visible in the upper right, the radial head in the upper left, ulnar articular surface in the lower left foreground, and the abnormal lateral coronoid process is in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.197  A hook probe placed through the craniomedial telescope portal is being used to apply pressure to a lateral coronoid process to determine if there is instability. The telescope is looking laterally from a medial portal with proximal or dorsal to the right and cranial is up in the picture. Humeral condyle is filling the right side of the image with ulnar articular surface on the left and the unstable lateral coronoid process in the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure 4.198), and rongeurs (Figure 4.199) are used for direct removal of loose fragments and soft bone or after mobilization with the curette. When all free fragments have been removed from the elbow joint, the bed of the defect has been adequately debrided, and coronoid process revision has been completed the joint is irrigated to remove debris. An instrument cannula or egress cannula is placed through the operative portal and the cannula is moved around the joint to vacuum out any debris (Figure  4.200). In the elbow joint, debris can be trapped between the cartilage surfaces and removal of these pieces is facilitated by

Figure 4.198  A curette is being used to mobilize abnormal bone from the lateral coronoid process of the ulna. The telescope is looking laterally from a medial portal with the curette placed through a lateral operative portal. Proximal or dorsal is up with cranial to the left. A sliver of humeral condyle is seen at the top of the image with a portion of the radial head on the left, ulnar articular surface in the bottom foreground, and the lateral coronoid process is in the center background directly below the curette. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.199  Removing a loose lateral coronoid process fragment from the elbow using 3.5mm Blakesley rongeurs passed through a lateral operative portal. The telescope is looking laterally from a medial portal with dorsal or proximal up and cranial to the left. Humeral condyle is visible filling the top of the image, a small portion of radial head is at the far-left, ulnar articular surface is across the bottom, and the rongeurs are positioned on the lateral coronoid process fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

moving the joint and using a small hook probe that will fit through the cannula. This hook is used to tease these small fragments loose so that they exit through the ­cannula. When the procedure has been completed instrumentation is removed and closure is with single interrupted skin sutures at each portal site.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.200  An egress cannula placed through the craniomedial operative portal being used for irrigation to remove debris from the elbow following arthroscopic surgery to manage medial coronoid process disease. Proximal or dorsal is up, medial is to the right, and the telescope is looking craniolaterally from a medial portal. Humeral condyle extends across the top of the image with medial coronoid process to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Stem cell therapy has become a standard addition to the process of arthroscopic debridement of the elbow joint. They have also been used in elbows without arthroscopic intervention (Kriston-Pál et al. 2017). This has shown a consistent improvement of results. Retreatment with stem cells has been done as many of the dogs seen with elbow dysplasia are young at the time of initial diagnosis and treatment with many years of life ahead of them. The retreatment interval averages about two years with a range of six months to eight years.

Figure 4.201  An OCD lesion seen to the left of center on the medial ridge of the humeral condyle that is a smooth free cartilage flap with a well-defined margin similar to a shoulder lesion. The telescope is in the standard medial telescope portal, proximal or dorsal is up on the image, and medial is to the left. Normal humeral condyle is to the upper right with reactive joint capsule protruding into the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5.2  Osteochondritis Dissecans (OCD) The distal humerus is a well-defined common site for OCD with most lesions being seen on the medial ridge of the humeral condyle (Bennett et al. 1981; Janutta and Distl 2008; Mason et al. 1980). The classic lesion seen in the shoulder joint with a well-defined free cartilage fragment with a clearly visible margin is seen in the elbow joint (Figure 4.201) but is a less common appearance than in the shoulder joint. Elbow OCD lesions also have a wide variety of presentations including an irregular small subtle blister-like cartilage surface appearance (Figure  4.202), an unbroken irregular surface (Figure  4.203), as coarsely fibrillated cartilage (Figure 4.204), finely fibrillated cartilage (Figure 4.205), fractured or fragmented cartilage (Figure  4.206), large obvious raised cartilage, blister-like, lesions with intact cartilage margins (Figure  4.207), and double raised

Figure 4.202  Subtle blister like appearance of the cartilage on the medial ridge of the humeral condyle representing an OCD lesion with no defined margins or visible loose cartilage. The telescope is looking cranially from the alternative medial telescope portal with dorsal or proximal up on the image and medial to the right. The medial humoral condyle is in the upper left with the ulnar articular surface to the lower right. The irregular cartilage in the center of the figure is the OCD lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.203  An OCD lesion on the medial ridge of the humeral condyle with an unbroken irregular surface and an indistinct but visible margin. The telescope is looking cranially from the alternative portal with proximal or dorsal up and medial to the right. Humeral condyle is present in the upper left with a small area of ulnar articular surface at the bottom and medial joint capsule on the right. The irregular cartilage in the center of the image is the lesion and an indistinct margin is visible as a line of fibrillated cartilage at the left side of the lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.204  Coarsely fibrillated cartilage as the presentation of an OCD lesion with a limited amount of intact free cartilage fragment on the medial ridge of the humeral condyle. The humeral condyle fills the upper left and the ulnar joint surface at the bottom is obscured with the fibrillated cartilage of the OCD lesion. Dorsal or proximal is up on the picture and medial is to the right with the telescope looking cranially from the alternative medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.205  An OCD lesion on the medial ridge of the humeral condyle seen as finely fibrillated cartilage. The telescope is looking cranially from a standard medial portal with medial to the right and proximal or dorsal up. The humeral condyle is seen across the top and the ulnar articular surface with significant medial coronoid process pathology is across the bottom of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.206  An area of fractured or fragmented cartilage representing an OCD lesion on the medial ridge of the humeral condyle. The telescope is looking cranially from a standard medial portal with medial to the left and proximal or dorsal up. The humeral condyle fills the upper right of the image with ulna and radial head indistinctly visible in the lower left background. Manipulation of this lesion with a palpation probe peeled cartilage away from bone in all directions from the visible lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.207  A large raised smooth, blister like, OCD lesion on the medial ridge of the humeral condyle that has not broken through the cartilage margins. Dorsal or proximal is up with medial to the right and the telescope is looking cranially from the alternative medial portal site. The humeral condyle is filling the upper left of the image with the blister protruding from the right side of the cartilage surface. Radial head and ulna are seen in the lower left background. Hyperemic synovial reaction is visible on the far right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

cartilage lesions (Figure  4.208). There is also great lesion margin appearance variation with indistinct poorly defined margins (Figure  4.209), indistinct but visible margins (Figure  4.210), fibrillated margins (Figure 4.211), and well-defined margins (Figure 4.212). Medial condyle OCD lesions occur most commonly centered not only on the highest portion of the ridge but also are seen on the medial margin of the condylar articular surface (Figure 4.213). OCD lesions are very rarely seen on the lateral ridge of the humeral condyle (Figure 4.214). Elbow OCD lesions are difficult to visualize and to document with captured images because of the close proximity of the telescope portal to the lesions. Humeral condyle OCD lesions are seen more frequently with medial coronoid process disease than they are as stand-alone lesions (Video 4.21). OCD lesions are easily distinguished from the humeral condyle lesions seen with medial coronoid process pathology because OCD lesions do not have the tapered feathering wear pattern at the cartilage margins (Figures 4.60, 4.89, 4.90, 4.113, 4.115, 4.120, and  4.131) and have full thickness cartilage at the lesion margins (Figure  4.215). The appearance of humeral condyle OCD lesions seen in combination with medial coronoid process disease is affected by the extent of humeral condyle cartilage

Figure 4.208  Large double raised blister lesions on the medial ridge of the humeral condyle indicating an OCD lesion. Medial is to the right and the humeral condyle is filling the upper left portion of the image. Normal humeral condyle cartilage extends from the left side to about the center where there is deviation of cartilage surface distally to form two blisters, one behind the other, with the near one extending to the margin of the visual field. Normal ulnar cartilage is seen in the bottom of the image with medial collateral ligament in the right center. A 20-gauge needle has been placed at the craniomedial portal site. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.209  A medial humeral condyle OCD lesion with poorly defined margins seen as an irregular raised area on the medial ridge of the humeral condyle. The telescope is looking cranially from the alternative medial portal with proximal or dorsal up and medial to the left. The tip of a normal medial coronoid process is seen to the lower right of the image with humeral condyle across the top, a small portion of radial head to the middle right, and medial collateral ligament to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.210  A fibrillated indistinct but visible margin of a medial ridge humeral condyle OCD lesion. Dorsal or proximal is up with medial to the right and the telescope is looking cranially from a standard medial telescope portal. The medial ridge of the humeral condyle almost completely fills the image with normal cartilage to the left, a line of fibrillated cartilage representing the lateral margin of the OCD lesion and raised cartilage of the OCD lesion is seen to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.211  Fibrillated cartilage along part of the lateral margin of an OCD lesion on the medial ridge of the humeral condyle with the remaining caudal margin seen as an indistinct but visible line of slightly whiter cartilage extending from the area of fibrillation to the far-right border of the image. The telescope is looking cranially from the alternative medial, or caudomedial, telescope portal with dorsal or proximal up and medial to the right. Humeral condyle fills the top of the image with normal cartilage to the left and the OCD lesion to the right, medial coronoid process to the lower left, reactive joint capsule to the bottom center, and a sliver of medial collateral ligament to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.212  The well-defined lateral margin of an OCD lesion on the medial humeral condylar ridge seen with the telescope in the alternative medial portal. Up is proximal or dorsal and medial is to the right. A 20-gauge needle is in place marking the location of the craniomedial operative portal. Normal cartilage is to the left with the lesion on the right side of the visible margin. Humeral condyle fills the top of the picture with radial head to the lower left, a coronoid process fragment covered with normal cartilage in the bottom center, and medial coronoid process is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.213  An OCD lesion on the medial margin of the medial ridge of the humeral condyle articular surface. Dorsal or proximal is up, medial is to the left, and the telescope is looking cranially from the alternative medial portal. Normal cartilage extends around the periphery of the image from the top down the right side with the lesion visible as raised irregular cartilage to the left on the medial side of the medial ridge of the humeral condyle. A normal medial coronoid process is seen at the bottom of the image with a small area of radial head in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.214  An unusual OCD lesion on the lateral ridge of the humeral condyle seen with the telescope looking laterally from a standard medial telescope portal. Dorsal or proximal is up and cranial is to the left. The lateral humeral condyle fills the top of the image with the OCD lesion seen as a raised blister like area in the background coming off the bottom of the visible humeral condyle. The ulnar articular surface is seen across the bottom of the figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.215  The bed of a medial humeral condyle lesion after removal of the free cartilage flap with a sharp full thickness cartilage margin that is typical for OCD lesions. Dorsal or proximal is up and medial is to the right with the telescope looking cranially from a standard medial portal. Exposed bone of the OCD lesion fills the top of the image with medial coronoid process to the lower right and radial head to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

chondromalacia caused by the medial coronoid process disease. With low-grade chondromalacia, the OCD lesions appear unaltered as shown in the descriptions of the previous paragraph. With advanced grades of chondromalacia, especially with Grade V lesions, they appear as a wear lesion on the medial ridge of the humeral con-

dyle with a depression in the bone filled with cartilage in the middle of the wear lesion (Figure  4.216). Combination lesions can also have unusual appearances due to the interaction of the two disease processes (Figure 4.217). Does OCD occur on the ulnar articular surface? OCD-like lesions have been seen on the ulnar articular surface as fractured cartilage with thick margins (Figure  4.218) and as osteocartilaginous lesions (Figure 4.219) in an area not typical for medial coronoid process disease. Arthroscopy for removal and debridement of humeral condyle OCD lesions uses the standard medial telescope portal (Figure 4.1), or a modified telescope portal caudal to the ulnar nerve (Figure 4.2), and a craniomedial operative portal (Figures 4.1 and 4.2). The typical location of OCD lesions on the medial ridge of the humeral condyle directly deep to the standard medial telescope portal makes visualization and manipulation difficult. The more caudal position of the modified telescope portal moves the telescope insertion point further away from the location of typical medial ridge lesions facilitating operative procedures yet still allows visualization of the medial coronoid process. Reversal of the standard telescope portal and the craniomedial operative portal is also used when needed to make the procedure easier. With the wide variation of humeral condyle OCD lesions exploration of the medial ridge of the humeral

Figure 4.216  A medial humeral condyle OCD lesion seen in the middle of Grade V chondromalacia lesion secondary to concurrent medial coronoid process disease. The medial ridge of the humeral condyle fills the right side of the image with lateral condylar ridge to the left. The irregular cartilage in the center of the exposed bone is the OCD lesion and this appearance is possible because the bed of the OCD lesion is below the level of the surrounding bone. Medial is to right with dorsal or proximal up and the telescope is looking cranially from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 4.217  An unusual medial humeral condyle OCD lesion appearance due to interaction of OCD with medial coronoid process disease. A free medial coronoid process bone fragment was wedged between the humeral condyle and the fixed portion of the medial coronoid process creating this wear groove with residual cartilage in the deep extent of the groove indicating an OCD lesion. Dorsal is up with medial to the left and the telescope is looking cranially from the alternative medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.218  An area of fractured or fragmented cartilage on the base of the medial coronoid process that appears more like an OCD lesion than chondromalacia or wear associated with medial coronoid process disease. Dorsal or proximal is up with medial to the right. The medial ridge of the humeral condyle is at the top of the image, the medial coronoid process is at the bottom, and the thick-walled cartilage defect at the center is the OCD like lesion. This is not the typical wear pattern of joint incongruity and is a very unusual location for and OCD lesion. This is not iatrogenic cartilage damage. Radial head is in the background to the left and synovial villi are seen to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.219  An osteocartilaginous lesion on the ridge of the semilunar notch of the ulna seen in the center of the picture as a curved demarcation line and a semilunar bone fragment. Is this an unusual ulnar OCD lesion or is this a variant of medial coronoid process disease? The telescope is looking laterally from a medial portal with proximal or dorsal to the upper left and cranial to the right. Humeral condyle is to the upper left with ulna to the lower right and radial head is in the upper right background. This slightly hyperemic lesion was present in an otherwise normal appearing joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

condyle is performed as part of all elbow arthroscopy procedures (Video 4.22). Normal appearing cartilage or very subtle chondromalacia (Figure 4.220) when probed (Figure 4.221) can reveal an OCD lesion (Figure 4.222). Removal of free flap lesions and areas of loose cartilage is performed in the same manner as for shoulder OCD lesions although manipulation is restricted by the narrow joint space. Free cartilage is elevated and freed with a hook probe (Figures 4.221 and 4.223) or a curved mosquito hemostat (Figure  4.224). Removal of the intact freed flap or fragments of the freed cartilage is performed using curved mosquito hemostats (Figure 4.225), arthroscopic grasping forceps, or arthroscopic rongeurs (Figure 4.226). Rongeurs are preferred over grasping forceps because if too much pressure is applied to the jaws a piece of cartilage is cut out of the free fragment rather than shattering the fragment that can happen with grasping forceps. Following complete removal of the free OCD cartilage the margins of the defect are evaluated for loose cartilage (Figure  4.227) and the cartilage margins are taken back to firmly attached cartilage using a curette (Figure  4.228). The mobilized cartilage pieces are removed with graspers, rongeurs, hemostats, or with an irrigation cannula (Figure 4.229). The bed of the OCD lesion is evaluated to determine if additional intervention is indicated. Exposed bleeding bone (Figure 4.229) does not require

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.220  A very subtle area of chondromalacia on the medial ridge of the humeral condyle seen during arthroscopy for medial coronoid process disease. The telescope is looking cranially from the alternative medial operative portal with the medial ridge of the humeral condyle filling the upper two thirds of the image. Medial is to the left and dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.221  Probing of the area of cartilage seen in Figure 4.220 using the 1.0mm hook probe easily elevated a flap of loose cartilage. The hook probe is inserted through a craniomedial operative portal, the telescope is looking cranially from the modified medial portal, dorsal or proximal is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

further debriding. Avascular bone exposed with cartilage removal (Figure  4.222) is managed either with a microfracture chisel (Figure  4.230) or gently with a straight curette (Figure  4.231) or if needed a curved curette (Figure  4.232). Elbow OCD lesion beds are debrided with hand instruments rather than a power shaver to minimize the amount of bone that is removed. Any fragments of loose bone or cartilage remaining in the bed of the lesion after cartilage extraction (Figure 4.233) are removed with a curette and irrigation.

Figure 4.222  The OCD lesion seen in Figures 4.220 and 4.221 after removal of the free cartilage flap and debridement of the osteocartilaginous defect. The telescope is looking cranially from the modified medial portal. Medial is to the left and dorsal or proximal is up. The medial ridge of the humeral condyle with the lesion fills the upper half of the image with the tip of the medial coronoid process visible at the bottom. Villus synovial reaction is present to the left and in the right center and the white area between the two hyperemic areas is the medial collateral ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.223  Elevation and freeing a medial ridge humeral condyle OCD lesion using the 2.0mm hook probe. Medial is to the left with dorsal up on the image, the telescope is looking cranially from a modified medial portal, and the probe is inserted through a craniomedial operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

When microfractures are created in the bed of lesions, loosened bone fragments (Figure  4.234) are removed with irrigation. Intra-articular irrigation fluid pressure used during arthroscopy, when high enough, interferes with bleeding from bone in the bed of OCD lesions (Figure  4.234) and reducing irrigation fluid pressure will allow observation to determine the efficacy of lesion curettage or microfracture techniques (Figure  4.233).

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Figure 4.224  Elevating the cartilage from a humeral condyle OCD lesion is being done using the tip of a curved mosquito hemostat inserted through a craniomedial operative portal. The free cartilage is fragmenting in this image rather than separating as a single flap of cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.225  Removal of a humeral condyle OCD free fragment using a curved mosquito hemostat. Dorsal or proximal is up, medial is to the right, the hemostat is inserted through a craniomedial portal, and the telescope is looking cranially from a modified medial portal. The fragment has been partially elevated leaving an area of attachment as is done with shoulder OCD lesions. The hemostat is closed on the freed cartilage with only the caudal or near side of the jaw visible. Humeral condyle with the OCD lesion fills the top of the image with medial coronoid process at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Hand instrumentation is used almost exclusively for management of OCD lesions in the elbow joint because power shavers are too aggressive, and it is too easy to remove an excessive amount of bone and cartilage.

Figure 4.226  Removal of a humeral condyle OCD fragment is being done using arthroscopic rongeurs in this patient. Proximal is up with medial to the right, the instrument is inserted through a craniomedial operative port, and the telescope is looking cranially from a modified medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.227  Following removal of the free cartilage fragment from an OCD lesion examination of the margin of the lesion is performed looking for any areas of loose osteocartilaginous tissue. A loose residual fragment is visible in this image as the prominent osteocartilaginous area on the right margin of the lesion adjacent to the reactive hyperemic villus synovial tissue. A subtle fracture line is visible across the top of the fragment. Dorsal or proximal is up on the image with medial to the right and the telescope is looking cranially from a modified medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

If a shaver is used a soft tissue or cartilage blade is used rather than a round burr. The oval soft tissue blades are less aggressive for removal of bone and their elongated cutting configuration makes it easier to create a smooth surface contour (Video 4.23).

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.228  Mobilizing the loose osteocartilaginous tissue from the OCD lesion seen in Figure 4.227 using an arthroscopic curette. Orientation and visible structures are the same as the previous figure with the curette inserted through a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.229  Using an irrigation cannula, seen in the lower right, to remove debris after extraction of OCD lesion cartilage with margin and bed debridement. Dorsal is up with medial to the right, the telescope is looking cranially from a modified medial portal, and the cannula is inserted through a craniomedial portal. Viable bleeding bone is visible in the bed of the lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Arthroscopic entry into the elbow joint occasionally fails to achieve an image of definable anatomic structures. This can occur with displaced (Figure 4.235) and very large (Figure 4.236) OCD lesions that fill the joint space or when the telescope is placed under the OCD lesion between the free cartilage flap and the bone (Figure 4.237). The telescope is repositioned until anatomic structures are defined.

Figure 4.230  A 70-degree microfracture chisel is being used to improve vascular access to the surface of an OCD lesion bed that appears avascular and sclerotic. Medial is to the left with dorsal up, the chisel is inserted through a craniomedial portal, and the telescope is looking cranially from the modified medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.231  A straight curette, visible at the lower right, is being used to gently debride the avascular bed of a humeral condyle OCD lesion. Medial is to the right with up dorsal or proximal. The telescope is looking cranially from a modified medial portal and the curette is inserted through a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Removal of elbow joint OCD lesions, although better than leaving fragments in place, does not achieve ideal long-term results. An alternative for consideration is injection of stem cells under loose OCD fragments with immobilization of the joint to attempt reattachment in an attempt for improved results. No known studies have been done in dogs to determine if reattachment can be achieved and if reattachment will produce improved long-term results.

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Figure 4.232  When access is difficult with a straight curette a curved curette is used to debride the bed of OCD lesions. Dorsal is up, medial is to the left, the curette is inserted through a craniomedial portal, and the telescope is looking cranially from a modified medial portal. Humeral condyle is to the upper right, medial coronoid process with exposed bone from medial coronoid process disease is to the lower left, radial head is behind the curette, and a medial coronoid process fragment bone defect is below the curette. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.234  Micro-fracturing of bone in the bed of OCD lesions also creates loose bone debris that is removed with irrigation leaving an irregular bone surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.235  In this patient a large, displaced OCD osteocartilaginous flap is interfering with visibility in an elbow joint because of its size. The free fragment fills the image except for a small area of lesion bed bone at the top. Repositioning of the telescope allowed a clear image. The telescope is looking cranially from a medial portal with dorsal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.233  Bone and cartilage debris is commonly seen in the bed of OCD lesions after removal of the loose cartilage flap. This debris is removed with curettage, rongeurs, and with irrigation. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5.3  Ununited Anconeal Process (UAP) Failure of the anconeal process ossification center to unite with the ulna is most commonly diagnosed in young large breed dogs especially the German Shepherd

Dog. UAP typically presents as a front leg lameness in young dogs with unilateral or bilateral elbow pain, with or without crepitus, and with or without joint capsule distension or joint thickening. Although typically a young dog disease UAP has been presented as an acute onset lameness in older dogs as late as eight years of age. Diagnosis is confirmed with lateral radiographs taken with the elbow in flexion. Ununited anconeal processes commonly occur bilaterally and arthroscopy is routinely performed bilaterally at the same procedure in these cases. In the authors’ experience, a very

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.236  A large displaced osteocartilaginous OCD lesion is seen filling the medial elbow joint space and blocking the visual field. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.237  An image with the telescope placed deep, between the large free OCD osteocartilaginous flap and the underlying bone, with no identifiable anatomic structures to allow orientation within the joint. When this occurs the telescope and joint are manipulated until an adequate visual field is achieved. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

high percentage, 75–80%, of dogs with an ununited anconeal process also has medial coronoid process pathology. The reported incidence is lower (MeyerLindenberg and Fehr 2006; Remy et al. 2004). The coronoid process must be evaluated and managed in these cases to achieve adequate results. In cases with unilateral involvement of the anconeal process bilateral arthroscopy is still recommended for assessment and management of medial coronoid process disease. Reported case series on the management of UAP have not addressed coronoid process pathology and lack of

good postoperative results have been attributed to failure of the anconeal process treatment technique rather than the possible effects of other joint pathology (Grøndalen and Rørvik 1980; Pettitt et al. 2009). Good long-term follow-up studies have not documented better results with screw fixation and the failure rate with screw fixation is excessive (Fox et  al.  1996; Pettitt et al. 2009). Ulnar osteotomies have been performed for UAP with inconsistent results and excessive morbidity expressed as prolonged pain until the osteotomy is completely healed. Results of ununited anconeal process removal studies need to be discarded and results evaluated in case series that have included coronoid process pathology management. Arthroscopic approach for ununited anconeal process fragment removal uses the standard medial telescope portal (Figure 4.1) and the standard craniomedial operative portal (Figure  4.1) for evaluation and revision of medial coronoid process disease. A caudomedial surgical approach or operative portal (Figure 4.1) is added for removal of the anconeal process fragment after completion of management of medial coronoid process pathology (Meyer-Lindenberg et  al.  2002b). The patient is positioned and prepared with the same protocol as for medial coronoid process arthroscopy. This facilitates performing the procedure bilaterally. Two monitors are needed with one at the head of the table and one at the foot of the table to facilitate working in both the cranial and caudal portions of the joint (Figure  2.5). The telescope is placed in the medial portal and the joint is examined. A craniomedial operative portal is established, and medial coronoid process disease is managed as indicated. After assessment and management of the medial coronoid process, the arthroscope is directed caudally for visualization of the anconeal process (Video 4.24). The cleavage line at the separation of the free anconeal process fragment from the ulna is usually easily visible (Figure 4.238). Appearance of the cleavage plane varies due to the degree if instability of the free fragment and displacement at the time of examination from a tight line of apposed cartilage (Figure  4.239), mild displacement with cartilage separation (Figure 4.238), moderate displacement allowing the telescope to be passed into the cleavage plane (Figure 4.240), and marked displacement where the fragment is floating free in the caudal joint compartment (Figure  4.241). Forces applied to position the joint for arthroscopic examination have an effect on fragment displacement and cleavage plane appearance. A caudomedial operative portal is established and is enlarged to allow removal of the free fragment in one piece if possible. This portal is more accurately a mini-

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Figure 4.238  An ununited anconeal process cleavage plane with mild displacement of the free fragment. The telescope is looking caudally from the standard medial telescope portal with proximal or dorsal up and medial is to the right. The free ununited anconeal process fragment is seen behind or deep to the cleavage plane in the foreground across the lower left of the image. Humeral condyle is curving across the top of the image and villus synovial reaction is seen to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.239  An ununited anconeal process cleavage plane with minimal displacement of the free fragment visible with the telescope looking caudolaterally from the standard medial telescope portal. The cleavage plane is seen as a roughened ridge of cartilage running across the right half of the center of the image with the ununited anconeal process fragment to the upper right, the ulnar articular surface to the lower right, and the lateral ridge of the humeral condyle to the left. An area of Grade II chondromalacia is present on the humeral condyle to the left of the cleavage plane. In this image proximal or dorsal is up with caudal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

arthrotomy rather than a true arthroscopy portal. Removal of the free fragment in multiple small pieces or with a power shaver is excessively time consuming and is avoided if possible. Portal location is determined by

Figure 4.240  An ununited anconeal process with moderate displacement of the free fragment with the telescope placed caudally into the cleavage plane from the standard medial telescope portal. Dorsal or proximal is up with medial to the left. A small portion of the articular cartilage of the olecranon fossa is seen on the right side of the image, the free ununited anconeal process fragment fills most of the upper left of the image, the cleavage plane is visible as the space in front of the telescope, and the dorsal surface of the olecranon is seen in the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.241  Marked displacement of an ununited anconeal process with the fragment floating free in the caudal joint compartment. The telescope is looking caudally from a medial portal and medial is to the right. The irregular bone mass in the upper center of the picture is the anconeal process fragment and to the lower left half of the image is the surface of the ulna where the anconeal process normally is attached. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

placing a 20-gauge needle into the caudal joint compartment from the medial side (Figure 4.242), making a stab incision with a no. 11 scalpel blade (Figure  4.243) to establish the initial portal which is enlarged with standard surgical technique to allow access to the fragment and removal. An arthroscopic or small surgical

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.242  A 20-gauge needle placed into the caudal joint compartment from the medial side to establish the location for a caudomedial operative portal. Dorsal or proximal is up on the image, medial is to the right, and the telescope is looking caudally into the caudal joint space from a standard medial portal. The needle is at an oblique angle directed distally, laterally, and cranially into the joint space. The bone with attached fibrous tissue seen to the right of center in the image is the free anconeal process fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.243  A caudomedial operative portal is established with a no. 11 scalpel blade inserted into the same track as the previously placed 20-gauge needle seen in the previous figure. Orientation is the same as the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­ eriosteal elevator is placed through the caudomedial p portal into the anconeal process cleavage plane (Figure  4.244) and the fragment is elevated off of the ulna. Large arthroscopic grasping forceps, large arthroscopic rongeurs (5–7.5 mm), or appropriate size open orthopedic surgery rongeurs are used for fragment removal (Figure  4.245). Rongeurs are preferred over

Figure 4.244  The anconeal process fragment is freed from its attachments to the ulna with a small periosteal elevator passed through the caudomedial operative portal. This is the same patient as seen in Figure 4.238 with the same orientation and visible anatomic structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.245  Large arthroscopic rongeurs (5.0mm to 7.5mm) or small open surgical rongeurs are used to grasp the free ununited anconeal process fragment for removal. The caudomedial operative portal is enlarged to accommodate these large instruments and the anconeal process fragment. Proximal or dorsal is up on the image, medial is to the right, and the rongeurs are inserted at an oblique angle. The free fragment is visible between the rongeur jaws and the white surface across the bottom of the image is where the anconeal process should be attached. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

grasping forceps because they get a better grip on the fragment and if griping is too aggressive, they remove a defined portion of the fragment rather than crushing or shattering the fragment. Following removal of the anconeal process fragment, the caudal joint compartment is evaluated for residual bone fragments (Figure  4.246)

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4.5.4  Degenerative Joint Disease (DJD)

Figure 4.246  After removal of the free anconeal process bone fragment the caudal joint compartment is examined for residual debris. The telescope is looking into the caudal joint space from a standard medial portal, medial is to the right, and dorsal or proximal is up. The white surface across the bottom left of the image is the dorsal surface of the olecranon including the area where the anconeal process should have attached. The hyperemic tissue in the upper right background is villus synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.247  An egress cannula is placed into the caudal joint compartment and any residual debris is removed with irrigation. The white surface in the lower left is the attachment area of the anconeal process and joint capsule is seen in the upper right. The telescope is looking caudally from a medial portal with dorsal up and medial to the right. Source: Timothy C. McCarthy.© John Wiley & Sons Inc.

and is irrigated thoroughly to remove debris (Figure 4.247). Closure is with single skin sutures in the medial and craniomedial portals and with layered surgical closure of the larger caudomedial portal.

Chronic severe degenerative elbow joint disease in older dogs is most commonly secondary to the various ramifications of elbow dysplasia with subsequent joint degeneration. These dogs present with lameness, limited range of elbow joint motion, and multiple intraarticular osteophytes that can be managed by arthroscopic debridement to improve range of motion, joint function, joint pain, and lameness. This joint debridement is commonly performed in conjunction with stem cell therapy and physical therapy. The most significant osteophytes that typically interfere with joint motion are those on the caudal aspect of the anconeal process and those on the dorsal aspect of the radial head. A multiport approach is used to access the medial joint space through the standard medial telescope and craniomedial operative portals, the caudal joint compartment through caudomedial and caudolateral joint portals, and the cranial joint space through medial, cranial, craniomedial, or craniolateral portals. A medial telescope portal and craniomedial operative portal are established first to assess the articular surfaces of the joint and the medial coronoid process, to remove coronoid process fragments, and to remove the coronoid process if indicated. The approach and management of these osteophytes was previously discussed under the individual pathologies. Results with this technique are variable from dramatic improvement to little or no improvement. Improved range of motion may be detected at the time of completion of the procedure, may not be seen for several weeks, or in some cases, optimum function may not be achieved without a program of postoperative physical therapy. Multiport elbow joint debridement is usually done as a unilateral procedure because the procedure is difficult and time consuming. This surgery is not to be taken on by the beginner.

4.5.5  Assisted Intra-Articular Fracture Repair Surgical repair of intracondylar fractures of the distal humerus and intra-articular ulnar fractures are facilitated using arthroscopy or an arthroscopic-assisted technique. Closed fracture reduction and screw or plate placement with arthroscopic guidance is the ideal concept. More practically, a limited open approach with arthroscopic-assisted fracture reduction and screw placement is performed. Assessment of the fracture site is enhanced using an arthroscope due to magnification produced by the telescope plus irrigation that clears the visual field (Figures 4.248 and 4.249). Evaluation of joint

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.248  An intra-condylar humeral fracture seen using arthroscopy through a limited open surgical approach. The telescope is looking caudally from a limited open approach to the cranial surface of the humeral condyle. Dorsal or proximal is up and lateral is to the right. The humeral condyle fills the upper right of the image, the fracture is visible to the right of center, and clotted blood is partially obscuring the fracture line. The joint space is at the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.249  An intra-articular ulnar fracture seen looking caudally from a standard medial telescope portal prior to a limited open approach for fracture reduction and implant placement. The humeral condyle is visible across the top of the picture with the distal ulnar fragment in the bottom foreground and the proximal olecranon fragment in the background on the right side. Proximal or dorsal is up and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

cartilage damage is improved with arthroscopy (Figure 4.250) revealing injuries that would otherwise be missed (Figure 4.251). Debriding fractures is facilitated by the magnification and improved view produced by arthroscopy (Figure  4.252), making removal of small debris possible that would otherwise be missed. Accuracy

Figure 4.250  Severe full thickness traumatic cartilage damage associated with the intra-articular ulnar fracture seen in Figure 4.249. The humeral condyle is seen across the top of the figure with the distal ulnar fracture segment at the bottom. Dorsal is up and caudal is to the right with the telescope looking caudolaterally from a medial telescope portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.251  Humeral condylar cartilage injury secondary to an intra-articular ulnar gunshot fracture. The depth of this lesion makes it Grade III chondromalacia. The humeral condyle articular surface fills the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

of fracture reduction is also improved due to magnification and an improved view of the fracture line and articular surfaces.

4.5.6  Biopsy of Intra-Articular Neoplasia Intra-articular neoplastic masses can be found with arthroscopy during elbow exploration in cases of lameness and elbow pain that do not have radiographic changes. Arthroscopy can also be used to obtain biopsies of physeal bone lesions seen on radiographs that are

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Figure 4.252  A small metallic fragment in an ulnar intra-articular gunshot fracture seen from a standard medial telescope portal. Dorsal or proximal is to the upper left and cranial is to the upper right. The metal fragment was removed with graspers prior to fracture reduction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

near or in the joint and in many cases, this will be the least traumatic approach for obtaining tissue samples (Figure 4.253).

Figure 4.253  A metastatic soft tissue sarcoma initially seen on radiographs as a lytic lesion in the proximal radius that was visible with arthroscopy and was successfully biopsied using minimally invasive technique. The radial head is in the lower right and the humeral condyle is in the upper left. Tumor tissue was flowing out of the bone defect during examination of the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

4.5.7  Immune-Mediated Erosive Arthritis Immune-mediated erosive arthritis is commonly discussed as occurring most frequently in the carpus and tarsus. Since this process involves multiple joints, any joint can be used to obtain diagnostic tissue samples. Immune-mediated arthritis with the elbow as the most obviously involved joint has been seen and diagnosis confirmed with biopsies taken from the elbow (Figure 4.254).

4.5.8  Incomplete Ossification of the Humeral Condyle (IOHC) This condition occurs when there is a failure of the two halves of the humeral condyle to fuse during development (Carrera et  al.  2008; Gabriel et  al.  2009; Gnudi et al. 2005; Martin et al. 2010; Moores and Moores 2017; Piola et al. 2012). Other names attached to this abnormality are humeral intracondylar fissure (Moores and Moores  2017) and incomplete humeral condylar fracture (Gnudi et al. 2005). IOHC is seen most commonly in Spaniels but also reported in other breeds. Presentation is commonly bilateral and is diagnosed with radiographs or CT. Intracondylar fractures in adult Spaniels are suspect for this diagnosis. Cartilage changes

Figure 4.254  Erosive immune mediated arthritis in the elbow of a dog. The appearance of the cartilage and bone in this joint was very different from the lesions seen with elbow dysplasia and biopsies confirmed the diagnosis of immune mediated disease. The medial margin of the medial coronoid process of the ulna is seen in the right foreground and the hemostat is inserted through a craniomedial portal. Dorsal or proximal is up with medial to the left and the telescope is looking craniolaterally from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

are visible with arthroscopy appearing as a linear cartilage abnormality in the sagittal plane at the intracondylar sulcus of the humeral trochlea. Changes are either an irregular raised cartilage ridge (Figure  4.255), a

4.5  ­Diseases of the Elbow Diagnosed and Managed with Arthroscop

Figure 4.255  An example of incomplete ossification of the humeral condyle seen as a ridge of cartilage in the trochlea of the humeral condyle. The telescope is looking craniolaterally from a standard medial portal with proximal or dorsal up and medial to the right. The humeral condyle is seen across the top of the picture with the sulcus in the center and the area of failure ossification is seen as the irregular sagittal ridge of cartilage in the sulcus. The radial head is visible in the bottom of the image with villus synovial reaction seen between the two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.256  A subtle sagittal cartilage cleft in the sulcus of the humeral condyle representing incomplete ossification of the humeral condyle. The telescope is angled dorsally so that it is looking directly at the humeral condyle from the medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

depressed cartilage cleft (Figure  4.256), or a band of chondromalacia (Figure  4.257). Patients with IOHC examined arthroscopically have had medial coronoid process disease with or without OCD.

4.5.9  Medial Enthesiopathy Abnormalities in the attachment of the carpal and digital flexor muscles on the medial epicondyle of the

Figure 4.257  A sagittal band of chondromalacia in the sulcus of the humeral condyle seen as another presentation of incomplete ossification of the humeral condyle. Proximal or dorsal is to the upper right and medial is to the left. The humeral condyle is filling the upper right with the radial head to the left and the semilunar notch of the ulna across the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 4.258  Avulsion of the origins of the carpal and digital flexor muscles from the medial epicondyle of the humerus. The epicondyle is on the left of the image and the avulsed tissue is on the right. Dorsal or proximal is up with lateral to the left and the telescope is looking cranially and dorsally medial to the epicondyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

humerus are a potential source of front leg lameness and elbow pain (de Bakker et al. 2012, 2013; Van Ryssen et al. 2012; Zontine et al. 1989). Although the etiology is unknown, injury (Zontine et  al.  1989), degenerative (Van Ryssen et  al.  2012; Meyer-Lindenberg and Heinen 2004), and ununited medial humeral ­epicondyle

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(Paster et  al.  2009) have been discussed. These abnormalities are commonly seen with elbow dysplasia and degenerative joint disease but can be seen independently of other pathology. When seen with elbow osteoarthritis, osteophytes and enthesiophytes occur in the same location and interfere with diagnosis. Ultrasound and CT examination of the origin of the flexor muscles

can be very helpful in establishing a diagnosis. Examination of the elbow joint medial to the medial epicondyle is achieved from the standard medial telescope portal by directing the telescope caudally and medially. Avulsion of the muscle from the epicondyle is identified arthroscopically (Figure 4.258).

­References de Bakker, E. & Saunders, J. et al (2012) Radiographic findings of the medial humeral epicondyle in 200 canine elbow joints. Vet. Comp. Orthop. Traumatol. 25, 359–65. de Bakker, E. & Samoy, Y. et al (2013) Arthroscopic features of primary and concomitant flexor enthesopathy in the canine elbow. Vet. Comp. Orthop. Traumatol. 26, 340–7. Barthélémy, NP. & Griffon, DJ. et al. (2014) Short-and long-term outcomes after arthroscopic treatment of young large breed dogs with medial compartment disease of the elbow. Vet. Surg. 43, 935–43. Bennett, D. & Duff, SR. et al. (1981) Osteochondritis dissecans and fragmentation of the coronoid process in the elbow joint of the dog. Vet. Rec. 109, 329–36. Botazzoli, AF. & Ferraresi, F. et al. (2008) Elbow dysplasia and lesions of the medial coronoid process: correlation between tomographic and arthroscopic findings in thirty cases. Vet. Res. Commun. 32 Suppl 1:S247–9. Burton, NJ. & Owen, MR. et al. (2011) Conservative versus arthroscopic management for medial coronoid process disease in dogs: a prospective gait evaluation. Vet. Surg. 40, 972–80. Carrera, I. & Hammond, GJ. et al. (2008) Computed tomographic features of incomplete ossification of the canine humeral condyle. Vet. Surg. 37,226–31. Coggeshall, JD. & Reese, DJ. et al. (2014) Arthroscopicguided ulnar distraction for the correction of elbow incongruency in four dogs. J. Small Anim. Pract. 55, 46–51. Coppieters, E. & Gielen, I. et al. (2015) Erosion of the medial compartment of the canine elbow: occurrence, diagnosis and currently available treatment options. Vet. Comp. Orthop. Traumatol. 28, 9–18. Coppieters, E. & Van Ryssen, B. et al. (2016a) Computed tomography findings in canine elbows arthroscopically diagnosed with erosion of the medial compartment: an analytical method comparison study. Vet. Radiol. Ultrasound 57, 572–81. Coppieters, E. & Seghers, H. et al. (2016b) Arthroscopic, computed tomography, and radiographic findings in 25

dogs with lameness after arthroscopic treatment of medial coronoid disease. Vet. Surg. 45, 246–53. Dempsey, LM. & Maddox, TW. et al. (2019) A comparison of owner-assessed long-term outcome of arthroscopic intervention versus conservative Management of Dogs with medial coronoid process disease. Vet. Comp. Orthop. Traumatol. 32, 1–9. Eljack, H. & Böttcher, P. (2015) Relationship between axial radioulnar incongruence with cartilage damage in dogs with medial coronoid disease. Vet. Surg. 44, 174–9. Evans, RB. & Gordon-Evans, WJ. et al. (2008) Comparison of three methods for the management of fragmented medial coronoid process in the dog. A systematic review and meta-analysis. Vet. Comp. Orthop. Traumatol. 21, 106–9. Fox, SM. & Burbidge, HM. et al. (1996) Ununited anconeal process: lag-screw fixation. J. Am. Anim. Hosp. Assoc. 32, 52–6. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Gabriel, P. & Pfeil, A. et al. (2009) Magnetic resonance imaging diagnosis: incomplete ossification of the humeral condyle in a German shepherd dog. J. Small Anim. Pract. 50, 92–4. Galindo-Zamora, V. & Dziallas, P. et al. (2014) Evaluation of thoracic limb loads, elbow movement, and morphology in dogs before and after arthroscopic management of unilateral medial coronoid process disease. Vet. Surg. 43, 819–28. Gnudi, G. & Martini, FM. et al. (2005) Incomplete humeral condylar fracture in two English pointer dogs. Vet. Comp. Orthop. Traumatol. 18, 243–5. Griffon, DJ. (2012) Chapter 53 surgical diseases of the elbow. In: Veterinary Surgery Small Animal. (eds. KM Tobias & SA Johnson) pp. 724–1. Elsevier Saunders, St Louis. Griffon, DJ. & Mostafa, AA. et al. (2018) Radiographic, computed tomographic, and arthroscopic diagnosis of radioulnar incongruence in dogs with medial coronoid disease. Vet. Surg. 47, 333–42.

  ­Reference

Grøndalen, J. & Rørvik, AM. (1980) Arthrosis in the elbow joint of young rapidly growing dogs. IV. Ununited anconeal process. A follow up investigation of operated dogs. Nord. Vet. Med. 32, 212–8. Groth, AM. & Benigni, L. et al. (2009) Spectrum of computed tomographic findings in 58 canine elbows with fragmentation of the medial coronoid process. J. Small Anim. Pract. 50, 15–22. Hans, EC. & Saunders, WB. et al. (2016) Fragmentation of the medial coronoid process in toy and small breed dogs: 13 elbows (2000–2012). J. Am. Anim. Hosp. Assoc. 52, 234–41. Janutta, V. & Distl, O. (2008) Review on canine elbow dysplasia: pathogenesis, diagnosis, prevalence and genetic aspects Dtsch. Tierarztl. Wochenschr., 115, 172–81. Jardel, N. & Crevier-Denoix, N. et al. (2010) Anatomical and safety considerations in establishing portals used for canine elbow arthroscopy. Vet. Comp. Orthop. Traumatol. 23, 75–80. Kramer, A. & Holsworth, IG. et al. (2006) Computed tomographic evaluation of canine radioulnar incongruence in vivo. Vet. Surg. 35, 24–9. Kriston-Pál, É. & Czibula, Á. et al. (2017) Characterization and therapeutic application of canine adipose mesenchymal stem cells to treat elbow osteoarthritis. Can. J. Vet. Res. 81, 73–8. Krotscheck, U. & Böttcher, PB. et al. (2014) Cubital subchondral joint space width and CT osteoabsorptiometry in dogs with and without fragmented medial coronoid process. Vet. Surg. 43, 330–8. Lau, SF. & Theyse, LF. et al. (2015) Radiographic, computed tomographic, and arthroscopic findings in Labrador retrievers with medial coronoid disease. Vet. Surg. 44, 511–20. Mariee, IC. & Gröne, A. et al. (2014) The role of osteonecrosis in canine coronoid dysplasia: arthroscopic and histopathological findings. Vet. J. 200, 382–6. Martin, RB. & Crews, L. et al. (2010) Prevalence of incomplete ossification of the humeral condyle in the limb opposite humeral condylar fracture: 14 dogs. Vet. Comp. Orthop. Traumatol. 23, 168–72. Mason, TA. & Lavelle, RB. et al. (1980) Osteochondrosis of the elbow joint in young dogs. J. Small Anim. Pract. 21, 641–56. Meyer-Lindenberg, A. & Fehr, M. (2006) Co-existence of ununited anconeal process and fragmented medial coronoid process of the ulna in the dog. J. Small Anim. Pract. 47, 61–5. Meyer-Lindenberg, A., & Heinen, V. et al. (2004) Incidence and treatment of metaplasia in the flexor

tendons attached to the medial humeral epicondyle in the dog. Tierarztl. Prax. Kleintiere 32:276. Meyer-Lindenberg, A. & Langhann, A. et al. (2002a) Prevalence of fragmented medial coronoid process of the ulna in lame adult dogs. Vet. Rec. 151, 230–4. Meyer-Lindenberg, A., Staszyk, C. et al. (2002b) Caudomedial approach for removal of an ununited anconeal process and assessment of the medial coronoid process of the ulna. J. Vet. Med. A Physiol. Pathol. Clin. Med. 49, 277–80. Moores, AP. & Moores, AL. (2017) The natural history of humeral intra-condylar fissure: an observational study of 30 dogs. J. Small Anim. Pract. 58, 337–41. Moores, AP. & Benigni, L. et al. (2008) Computed tomography versus arthroscopy for detection of canine elbow dysplasia lesions. Vet. Surg. 37, 390–8. Outerbridge RE: The etiology of chondromalacia patellae. J. Bone Joint Surg. 43:752, 1961. Paster, ER. & Biery, DN. et al. (2009) Un-united medial epicondyle of the humerus: radiographic prevalence and association with elbow osteoarthritis in a cohort of Labrador retrievers. Vet. Surg. 38, 169–72. Pettitt, RA. & Tattersall, J. et al. (2009) Effect of surgical technique on radiographic fusion of the anconeus in the treatment of ununited anconeal process. J. Small Anim. Pract. 50, 545–8. Piola, V. & Posch, B. et al. (2012) Magnetic resonance imaging features of canine incomplete humeral condyle ossification. Vet. Radiol. Ultrasound 53, 560–5. Remy, D. & Neuhart, L. et al. (2004) Canine elbow dysplasia and primary lesions in German shepherd dogs in France. J. Small Anim. Pract. 45, 244–8. Samoy, Y. & Van Ryssen, B. et al. (2006) Review of the literature: elbow incongruity in the dog. Vet. Comp. Orthop. Traumatol. 19, 1–8. Samoy, Y. & Van Vynckt, D. et al. (2012) Arthroscopic findings in 32 joints affected by severe elbow incongruity with concomitant fragmented medial coronoid process. Vet. Surg. 41, 355–61. Samoy, YC. & de Bakker, E. et al. (2013) Arthroscopic treatment of fragmented coronoid process with severe elbow incongruity. Long-term follow-up in eight Bernese Mountain Dogs. Vet. Comp. Orthop. Traumatol. 26, 27–33. Skinner, OT. & Warren-Smith, CM. et al. (2015) Computed tomographic evaluation of elbow congruity during arthroscopy in a canine cadaveric model. Vet. Comp. Orthop. Traumatol. 28, 19–24. Staiger, BA. & Beale, BS. (2005) Use of arthroscopy for debridement of the elbow joint in cats. J. Am. Vet. Med. Assoc. 226, 401–3.

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Tatarunas, AC. & Matera, JM. (2006) Arthroscopic study of the elbow joint in dog cadavers Acta Cir. Bras. 21, 362–5 Van Ryssen, B. & van Bree, H. (1997) Arthroscopic findings in 100 dogs with elbow lameness. Vet. Rec. 140, 360–2. Van Ryssen, B. & van Bree, H. et al. (1993) Elbow arthroscopy in clinically normal dogs Am. J. Vet. Res. 54, 191–8. Van Ryssen, B. & de Bakker, E. et al. (2012) Primary flexor enthesopathy of the canine elbow: imaging and arthroscopic findings in eight dogs with discrete radiographic changes. Vet. Comp. Orthop. Traumatol. 25, 239–45.

Villamonte-Chevalier, A. & van Bree, H. et al. (2015) Assessment of medial coronoid disease in 180 canine lame elbow joints: a sensitivity and specificity comparison of radiographic, computed tomographic and arthroscopic findings. BMC Vet. Res. 25, 243. Wagner, K. & Griffon, DJ. et al. (2007) Radiographic, computed tomographic, and arthroscopic evaluation of experimental radio-ulnar incongruence in the dog. Vet. Surg. 36, 691–8. Zontine, WJ. & Weitkamp, RA. et al. (1989) Redefined type of elbow dysplasia involving calcified flexor tendons attached to the medial humeral epicondyle in three dogs. J. Am. Vet. Med. Assoc. 194, 1082–5.

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5 Radiocarpal Joint Arthroscopy of the radiocarpal joint is indicated when there is front leg lameness with carpal pain, crepitus, swelling, thickening, or instability; radiographic changes showing intra-articular fractures or degenerative joint disease. The carpal joint is a commonly recommended site for synovial biopsies to diagnose immune-mediated polyarthritis. Carpal joint disease is commonly accompanied by significant joint swelling or thickening making localization of the involved joint easier than with more proximal joints.

5.1 ­Patient Preparation, Positioning, and Operating Room Setup Radiocarpal joint arthroscopy is typically performed as a unilateral procedure. The patient is placed in dorsal or lateral recumbency with the leg to be evaluated on the upper side and with the involved leg suspended for preparation and draping. For examination in dorsal recumbency, the leg is extended caudally beside the body, and for the lateral recumbent position, the leg is placed at a normal standing angle and is rotated externally. A monitor is placed across the table from the surgeon when the lateral position is used (Figure 2.6) and at the head of the table for the dorsally recumbent position (Figure 2.4). An assistant stands caudal to the surgeon when the lateral position is used and cranial to the surgeon between the surgeon and monitor if the dorsal position is used. Dorsal recumbency is used for the occasional bilateral procedure with the legs extended caudally, the monitor at the head of the table, and the assistant standing cranial to the surgeon (Figure 2.4). If carpal fusion or other open surgical procedure is a consideration following arthroscopy, this is taken into account in positioning the patient to allow a smooth transition without repositioning or redraping.

5.2 ­Portal Sites and Portal Placement All portals for the radiocarpal joint are on the cranial or dorsal aspect of the joint (Figure 5.1). Portals are placed medial and lateral to the common digital extensor tendon with the telescope portal placed on the side of the tendon away from the area of interest. This allows placement of an operative portal directly over the lesion. The radiocarpal joint is very small and frequently there is not enough room for three portals, so an egress portal is not placed, and egress is allowed through the operative portal. If an egress portal is needed, it can be established medial or lateral to either of the other two portals. The portal sites are established by flexing the carpus and palpating the indentation of the radiocarpal joint space medial and lateral to the common digital extensor, a 20-gauge 1″ needle is placed into the joint, joint fluid is aspirated, the joint is distended with saline, a stab incision is made with a no. 11 scalpel blade, and the telescope cannula is placed into the joint using the blunt obturator. Initial egress is allowed through the 20-gauge needle until an operative portal is established. The portal site on the dorsal aspect of the joint not used for the telescope portal is used for an operative portal. A 20-gauge 1″ needle is placed in the joint to accurately confirm portal site placement and a stab incision is made into the joint with a no. 11 scalpel blade. Instrumentation is passed directly into the joint without an instrument cannula.

5.3 ­Nerves of Concern with Radiocarpal Joint Arthroscopy The lateral branch of the superficial radial nerve courses across the dorsal surface of the radiocarpal joint with the tendon of the extensor carpi radialis. This nerve

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

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Figure 5.2  The radiocarpal joint space with the distal articular surfaces of the radius in the foreground and the ulna in the background with the radioulnar ligament between the two bones in the upper right of the image. The dorsal articular surface of the radiocarpal bone is seen in the lower left of the image. Proximal in this picture is to the upper right and cranial is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 5.1  Portal sites on the dorsal aspect of the radiocarpal joint. The portals shown are two interchangeable sites for telescope and operative portals (asterisks) medial and lateral to the common digital extensor tendon. Source: Modified from Freeman (1999). © 1999, Elsevier.

with the cranial superficial antebrachial artery and the accessory cephalic vein lies between the two interchangeable portals (asterisk) on the dorsal aspect of the joint (Figure  5.1). At the level of the carpal joint, this nerve contains only sensory fibers. The combined neurovascular bundle is palpated and avoided when establishing these portals.

5.4 ­Examination Protocol and Normal Arthroscopic Anatomy Upon entering the radiocarpal joint orientation is established using the distal articular surface of the radius and ulna, proximal articular surface of the radial carpal bone, and the joint space looking either laterally (Figure 5.2) or medially (Figure 5.3). Space within the radiocarpal joint is limited, and examination requires careful manipulation of the joint through flexion and extension using

Figure 5.3  The cranial radiocarpal joint space with the telescope directed medially. The dorsal articular surface of the radiocarpal bone is filling the bottom of the image with the cranial tip of the distal radius on the right and the joint capsule across the top of the image. Proximal is to the upper right and cranial is to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

small movements of the telescope in depth, angle, and rotation. The distal articular surfaces of the radius and ulna with the radioulnar ligament (Figure 5.2), the proximal surface of the radial carpal bone (Figures 5.2 and 5.3), the dorsal surface of the accessory carpal bone (Figure 5.4), the dorsal joint space (Figure 5.3), and the palmar ulnocarpal ligament of the joint (Figure 5.5) are examined (Warnock and Beale  2004). Transposing the telescope between the two dorsal portal locations facilitates a complete examination of the joint.

5.5  ­Diseases of the Radiocarpal Joint Diagnosed and Managed with Arthroscop

Figure 5.4  The cranial articular surface of the accessory carpal bone is visible in the palmar portion of the radiocarpal joint in the background behind the palmar ulnocarpal ligament seen on the left and the distal articular surface of the radius in the upper right. Proximal is up on the image and the telescope is looking caudally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 5.6  A sagittal radial carpal bone fracture that was diagnosed on an AP projection radiograph of the joint. The radiocarpal bone fills the lower left of the image with the fracture line seen as a step in the bone running horizontally across the picture. A small portion of distal radius is seen in the upper right. The telescope is looking caudally with proximal up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 5.5  The palmar ulnocarpal ligament seen in the palmar portion of the joint as the vertical band of tissue filling the center of the image. A small portion of radius is seen across the top of the image. Proximal is up in the picture and the telescope is looking caudally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

5.5 ­Diseases of the Radiocarpal Joint Diagnosed and Managed with Arthroscopy 5.5.1 Fractures Evaluation and management of radial carpal bone fractures can be assisted with arthroscopy primarily from a diagnostic standpoint to facilitate decision making for treatment selection (Perry et  al.  2010). Assessment of fracture pattern (Figures 5.6 and 5.7) and evaluation of

Figure 5.7  A transverse fracture of the radial carpal bone in Figure 5.6 that was not visible on radiographs of the joint. If the fracture seen in Figure 5.6 and on radiographs was the only fracture is was repairable with a transverse screw. The transverse fracture prevented this repair as it was in the location needed for placement of the screw. The radiocarpal bone fills the lower right of the image and the fracture line is seen as the defect in the radiocarpal bone at the bottom of the picture. Villus synovial reaction is seen to the upper left and a small portion of the distal radius is seen to the upper right. Proximal is to the upper right and cranial is to the left with the telescope looking medially. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 5.8  A sagittal radial carpal bone fracture line in a three year old neutered male German Shorthair Pointer that had been treated with a splint for over six months. The joint was examined with arthroscopy prior to surgery to evaluate the condition of the cartilage as part of the process of deciding to repair the fracture or fuse the joint. The cartilage surfaces were normal other that at the immediate fracture line. The radiocarpal bone fills the lower left of the image with the distal radial articular surface to the upper right. Proximal is up on the image, medial is to the left, and the telescope is looking caudally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

articular cartilage damage (Figure 5.8) is more accurate and less invasive than open exploration. Dorsal slab fractures of the radial carpal bone that are not structural and chip fractures from the dorsal margin of the distal articular surface of the radius can be diagnosed (Figure  5.9) and removed (Figure  5.10a–d) with arthroscopy.

5.5.2  Soft Tissue Injuries Any and all the soft tissue structures in and around the radiocarpal joint can be injured, and arthroscopy provides a minimally invasive approach for diagnosis, to

Figure 5.9  A dorsal chip fracture fragment from the cranial aspect of the distal radius visible on the right with the radius to the left and the fracture line seen as a vertical gap between the bones. The dorsal surface of the radiocarpal bone is in the lower left of the image. Proximal is up on the picture and cranial is to the right. The chip fragment was removed with a mini-arthrotomy and arthroscopic guidance. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

select and plan open operative procedures, and for treatment. Extensive ligament injuries require open surgical stabilization with either ligament reconstruction or carpal fusion and are not managed with arthroscopy. Dorsal joint capsule injuries have been treated with thermal modification and external splint support.

5.5.3  Immune-Mediated Erosive Arthritis Arthroscopy is an effective method for joint examination and biopsy collection in cases of suspected immunemediated arthritis.

 ­Reference

(a)

(b)

(c)

(d)

Figure 5.10  A chronic chip fracture fragment originating from the cranial margin of the distal radius visible in the dorsal joint space of the radiocarpal joint seen with the telescope looking medially from a craniolateral portal. Proximal is to the upper left on this series of images with cranial to the upper right. (a) The chip is seen in the upper right of the image with the radiocarpal bone to the lower right and the distal radial articular surface to the upper left. (b) 20 gauge needle placed into the joint from the cranial surface to establish the best location for a craniomedial operative portal. The needle is between the fragment on the right and the radius on the left. (c) Rongeurs placed from a craniomedial portal for removal of the fracture chip. (d) The bed of the chip fragment after removal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­References Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Perry, K. & Fitzpatrick, N et al. (2010) Headless selfcompressing cannulated screw fixation for treatment of

radial carpal bone fracture or fissure in dogs. Vet. Comp. Orthop. Traumatol. 23, 94–101. Warnock JJ. & Beale BS. (2004) Arthroscopy of the antebrachiocarpal joint in dogs. J. Am. Vet. Med. Assoc. 224, 867–74.

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6 Hip Joint The most common indication for arthroscopy of the hip joint is young dogs with hip dysplasia to assess articular cartilage condition prior to performing corrective pelvic osteotomy surgery (Holsworth et al. 2005), either triple pelvic osteotomy (TPO) or double pelvic osteotomy (DPO). Arthroscopy provides more information for case selection and for improving results with TPO/DPO surgery than can be obtained with other less invasive techniques. The patient is prepared for the TPO/DPO surgery, and arthroscopy is performed as the first step of the procedure. If the patient is found to be a good candidate for TPO/DPO with arthroscopy, the surgery is performed. If the patient is not a good candidate for TPO/ DPO based on the arthroscopic findings, the procedure is terminated and the patient is recovered. Other indications for hip joint arthroscopy are hip joint pain or crepitus not associated with hip dysplasia, radiographic evidence of intra-articular fractures, degenerative changes not typical of hip dysplasia (Luther et al. 2005), hip luxation (Segal et  al.  2018), or periarticular lytic lesions.

6.1 ­Patient Preparation, Positioning, and Operating Room Setup Since the most common indication for hip joint arthroscopy is in dysplastic dogs immediately prior to TPO/ DPO surgery, the patient is clipped, positioned on the table with the leg suspended, prepared, and draped for the TPO/DPO surgery. The monitor is placed cranial to the patient, and the surgeon stands dorsal to or at the caudal end of the table with the assistant on the ventral side of the patient (Figure 2.8). Alternatives are to place the monitor dorsal to the patient far enough cranially to be out of the way of the sterile field for surgery and for

the surgeon to stand at the caudal end of the patient with the assistant ventral to the patient. Positioning is the same for other indications unless a planned operative procedure dictates otherwise.

6.2 ­Portal Sites and Portal Placement All portals for the hip joint are on the dorsal aspect of the joint (Figure  6.1). The telescope portal is placed directly dorsal to the greater trochanter, and an egress needle or portal is placed either cranial or caudal to the telescope portal. Access to the hip joint is very easy in young dysplastic dogs because of the hip laxity. To establish the telescope portal, ventral traction is applied to the limb and the proximal femur is pushed down or medially. A 2″ to 3″ 20-gauge spinal needle is inserted into the joint in a medial direction immediately dorsal to the greater trochanter, joint fluid is aspirated, and the joint is distended with saline. A stab incision is made in the skin, fascia, and muscle at the portal site with a no. 11 scalpel blade, the portal tract is deepened with blunt dissection using a curved mosquito hemostat, and the telescope cannula is placed into the joint using the blunt obturator (Figure  6.2). With the joint positioned as described, there is adequate space for positioning the telescope (Figure  6.3). For joint exploration prior to TPO/DPO surgery, egress through the initial arthrocentesis needle or a second needle is adequate and establishing an egress portal is not required. Operative procedures are not commonly performed in the hip joint, and an operative portal is not typically placed but if needed can be placed either cranial or caudal to the telescope portal. A hip distraction device was evaluated for use when adequate distraction is not possible (Devesa et al. 2014).

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

6.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 6.1  Portal sites on the dorsal aspect of the hip joint. The three portal sites shown are the dorsal telescope portal (asterisk) with craniodorsal and caudodorsal operative or egress portal sites (Triangles). Source: Modified from Freeman (1999) Modified Drawing. © John Wiley & Sons.

Figure 6.3  An anterior–posterior drawing of the hip joint demonstrating positioning of the telescope. Source: Modified from Freeman (1999) Modified Drawing. © John Wiley & Sons.

continues caudally to bend around the caudal aspect of the joint. The sciatic nerve lies a sufficient distance from the hip joint so there is little risk of damage during placement of the dorsal telescope portal (Figure  6.1). The caudal operative or egress portal is closer to the nerve placing it at risk but with the portal location technique using a needle observed with the telescope risk is minimal.

6.4 ­Examination Protocol and Normal Arthroscopic Anatomy

Figure 6.2  Positioning of the telescope vertically into the joint space for examination of the joint. Source: Modified from Freeman (1999) Modified Drawing. © John Wiley & Sons.

6.3 ­Nerves of Concern with Hip Joint Arthroscopy The sciatic nerve courses across the dorsolateral aspect of the pelvis medial and dorsal to the hip joint and then

Orientation in the hip joint utilizes the round ligament, the concave articular surface of the acetabulum, and the convex articular surface of the femoral head (Figure 6.4). A common tendency is to insert the arthroscope too deeply so that the tip is in the tissues of the acetabular fossa obscuring identification of structures needed for orientation. Retraction of the telescope will bring the anatomy into view. The joint is examined in a systematic manner (Video 6.1) to assess the entire articular surface of the acetabulum including the cranial extent (Figure 6.5), central portion (Figure 6.6), caudal end of the transverse acetabular ligament (Figure 6.7), caudal tip of the acetabulum (Figure  6.8), and dorsal acetabular rim with the labrum and attached joint capsule (Figure  6.9). The articular surface of the femoral head is examined with particular attention given to the

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Figure 6.4  The medial aspect of the femoral head articular surface seen to the lower left, the medial concave portion of the dorsal aspect of the central or dorsal acetabular articular surface seen to the upper right, and the round ligament seen in the center background are used for orientation in the joint. The telescope is looking medially from a lateral portal with dorsal to the upper right and cranial to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.7  The cranial tip of the acetabular articular surface is seen in the lower left of the image, a small portion of the cranial aspect of the femoral head articular surface is in the upper left and the cranial end of the ventral acetabular ligament is running horizontally across the center of the picture. A small portion of fat in the acetabular fossa is visible in the lower left. The telescope is looking medially from a lateral telescope portal with lateral up on the image and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.5  The cranial aspect of the acetabular articular surface is filling the top of the image and the cranial aspect of the femoral head articular surface is seen to the lower left. The cartilage surfaces are normal. There is very mild disruption of the labrum of the acetabulum in the upper right aspect of the image. The telescope is looking craniomedially from a lateral portal with dorsal up on the image and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.8  The caudal tip of the acetabulum in the center background seen articulating with the caudal aspect of the femoral head to the lower left and showing attachment of the dorsal joint capsule in the upper right of the picture. The telescope is looking caudally from a lateral portal with dorsal up on the image and lateral to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.6  The central or dorsal portion of the acetabular articular surface is seen in the background with the dorsal aspect of the femoral head articular surface filling the bottom of the image. A small portion of the lateral acetabular rim is seen out of focus in the upper right. The telescope is looking craniomedially from the lateral portal with dorsal up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.9  The dorsal rim of the acetabular articular surface seen with the dorsal acetabular articular surface in the lower left, the dorsal acetabular rim curving across the center of the image, the dorsal cartilaginous labrum seen as a band of rounded tissue slightly darker than the acetabular cartilage, and dorsal joint capsule on the right. The telescope is looking cranially from a lateral telescope portal with dorsal to the upper right and lateral to the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.4  ­Examination Protocol and Normal Arthroscopic Anatom

dorsal surface (Figures  6.6, and  6.10), medial surface immediately dorsal to the fovea capitis (Figure 6.4), and the dorsal margin of the articular surface on the femoral neck (Figure 6.11). Soft tissue structures that are evaluated include the dorsal labrum of the acetabulum and

dorsal joint capsule (Figure  6.9), round ligament (Figure 6.12), ventral acetabular ligament (Figure 6.7); the cranial (Figure 6.13), caudal (Figure 6.8), and ventral (Figure  6.14) joint compartments; and the dorsal femoral head and neck (Figure 6.15).

Figure 6.10  The dorsal aspect of the femoral head is filling the lower left half of the image with the acetabular articular surface in the upper right. This area of the femoral head is the area of most importance in assessing acceptance for pelvic osteotomy surgery because this will be the new weight bearing surface after surgery. The telescope is looking cranially from a lateral portal with lateral to the upper left and dorsal to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.12  The round ligament is running vertically across the center of the image, originating in the acetabular fossa at the top, and inserting on the fovea capitis of the femoral head at the bottom. The telescope is looking medially from a lateral telescope portal with dorsal up and cranial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.11  The dorsal margin of the femoral head articular cartilage seen as a white band running at an angle across the upper center of the image, the dorsal aspect of the intra-articular femoral neck is visible as slightly pink tissue with small blood vessels filling the lower left of the picture, and dorsal joint capsule is in the background on the upper right. The telescope is looking cranially from a lateral telescope portal with dorsal up and lateral to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.13  The cranial joint space in a dog with the cranial aspect of the femoral head seen on the far left, the acetabular articular surface in the lower right, and the joint capsule with slightly increased blood supply filling the upper center of the image. Minor degenerative changes are seen in this picture as a slight roughening of the margin of the articular cartilage in the right center of the image. This change is secondary to an old untreated fracture but the lameness in this dog was due to a partially ruptured cranial cruciate ligament. The telescope is looking craniomedially from a lateral telescope portal with lateral up and cranial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 6.14  The ventral joint space of the hip is seen in the background beyond the femoral head at the top of the picture, the caudal acetabular cartilage is in the lower left, the transverse acetabular ligament is seen indistinctly as a white band running to the right from the tip of the acetabular cartilage, and acetabular fossa fat is seen to the right between the acetabular cartilage and the transverse acetabular liga­ment. The telescope is looking medially from a lateral telescope portal with lateral up on the image and cranial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.16  Fine cartilage fibrillation on the medial aspect of the femoral head in a young dog with hip dysplasia. This represents Grade II or III chondromalacia. The telescope is looking medially from a lateral telescope portal with medial up on the image and cranial is to the left. The femoral head fills the lower left with the acetabular articular surface curving across the upper right of the image and the acetabular fossa is seen in the background at the center of the image. The area of chondromalacia is an indistinct fuzzy area immediately across from the acetabular fossa and partially obscuring the round ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.15  The dorsal femoral neck is seen filling the bottom left of the image with attachment of the dorsal joint capsule curving away from the bone at the far left and extending across the top of the image. The cranial joint capsule is visible in the background. A small portion of femoral head cartilage curves down in the lower right of the picture. The telescope is looking cranially from a lateral portal with dorsal up on the image and medial to the right. There is a small amount of reaction in the joint capsule on the femoral neck secondary to hip dysplasia. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.17  Coarse fibrillation of cartilage, Grade III chondromalacia, on the same area of the medial surface of the femoral head as in the previous figure seen in a dysplastic hip joint of a young dog. In this picture the femoral head is on the right and the acetabulum is on the left. The telescope is looking medially from a lateral portal with lateral to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5 ­Diseases of the Hip Diagnosed and Managed with Arthroscopy 6.5.1  Hip Dysplasia Areas of primary interest with arthroscopy of the hip in young dysplastic dogs prior to performing pelvic osteotomy surgery are the joint surfaces that will come into

use with repositioning of the acetabular cup. These areas include the dorsal surface of the femoral head, the dorsal margin of the femoral articular surface with the femoral neck, and the central portion of the acetabular articular surface. The cartilage wear pattern on the femoral head from subluxation is evaluated for extent, severity, and position. The typical wear pattern is on the medial aspect of the femoral head immediately dorsal to the fovea capitis and can appear as fine (Figure 6.16) or coarse fibrillation (Figure  6.17), partial-thickness

6.5  ­Diseases of the Hip Diagnosed and Managed with Arthroscop

c­ artilage erosions (Figures 6.18 and 6.19), variable sized full-thickness cartilage loss (Figure  6.20), and lesions with eburnation of exposed bone that can be either circular (Figure 6.21) or linear (Figure 6.22). Small lesions in this area, on the medial aspect of the femoral head (Figures 6.16–6.20), do not interfere with joint function

Figure 6.18  A partial thickness cartilage erosion of the medial aspect of the femoral head in a young dog due to hip dysplasia. This lesion is also Grade III chondromalacia. This lesion is seen as a slightly roughened area and has different appearance than the previous two images in that there is no fibrillation but there is loss of cartilage thickness. The telescope is looking medially from a lateral portal with dorsal down in the picture. The femoral head is in the upper left with the acetabular articular surface curving across the bottom right and the round ligament is filling the center of the image. The round ligament in this patient is indistinct due to partial tearing secondary to hip laxity and overlying synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.19  A more clearly defined partial thickness cartilage erosion, Grade II chondromalacia, seen as a slightly darker smooth area on the medial surface of the femoral head in a dysplastic hip joint in a young dog. The femoral head is on the left with the acetabulum on the right. The telescope is looking medially from a lateral portal with dorsal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.20  : A full thickness cartilage wear lesion on the medial surface of the femoral head in a young dog with hip dysplasia. This lesion represents Grade IV chondromalacia. There is an area of exposed bone in the center of the lesion with relatively thick margins and an area of fibrillation along the deep edge of cartilage damage. The femoral head is on the left and the acetabulum is on the right with a severely damaged round ligament seen as ruptured ligament fibers in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.21  A large full thickness cartilage wear lesion with exposed eburnated bone, Grade V chondromalacia, on the medial aspect of the femoral head secondary to hip subluxation in a young dog with hip dysplasia. The femoral head fills the top of the image with the acetabulum across the bottom. There is normal cartilage on the dorsal aspect of the femoral head across the very top of the picture with a darker tan area of exposed eburnated bone below the area of normal cartilage. There is cartilage across the medial acetabular surface in the background, a large area of exposed bone is seen lateral to the cartilage, and irregular damaged labrum and joint capsule in the foreground at the very bottom of the picture. A small projection of fibrillated tissue is seen deep to the center of the cartilage loss on the femoral head and this is a remnant of the round ligament. The telescope is looking medially from a lateral portal and dorsal is down on the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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following acetabular repositioning, but large lesions in this area (Figure 6.21) and any lesions on the dorsal or dorsomedial area of the femoral head (Figure  6.23) decrease the prognosis for good function following surgery. Significant osteophytes on the dorsal rim of the femoral head and femoral neck (Figure 6.24) can inter-

fere with a range of joint abduction following acetabular repositioning. Acetabular osteophytes form primarily in the acetabular fossa as either flat bone filling the fossa (Figure 6.25) or as raised more typical osteophytes on the ventral margin of the fossa (Figure 6.26). Changes in the acetabular articular surface secondary to hip

Figure 6.22  A linear full thickness cartilage wear lesion is seen on the medial surface of this femoral head in a dysplastic hip. This lesion also represents Grade V chondromalacia. The telescope is looking medially from a lateral portal and dorsal is to the right. The femoral head is on the left with normal cartilage on its dorsal surface at the far left and a band of exposed darker tan eburnated bone running vertically in the center of the image with acetabulum on the right. A ruptured round ligament is seen as irregular tissue in the background between the femoral head and acetabulum. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.24  A large ridge of osteophytes is seen on the dorsal aspect of the femoral neck lateral to the margin of the femoral head articular cartilage in a dog with severe hip dysplasia. The femoral head is on the left side with the femoral head articular cartilage at the bottom and the joint space at the far right. The acetabulum is beyond the margin of the image. The irregular white ridge across the top of the image is the ridge of osteophytes. There is an unexplained indentation on the far-left side of the ridge with exposed bone. The telescope is looking medially from a lateral portal and lateral is up on the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.23  An area of cartilage damage is seen on the dorsal surface of the femoral head, on the right side of the picture, in the area that will become weight bearing after surgical repositioning of the acetabulum. The opposing acetabular articular surface, on the left, also shows cartilage abnormality as irregular swelling and an irregular surface representing Grade I chondromalacia. The telescope is looking medially from a lateral portal and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.25  A flat osteophyte is seen partially filling the dorsal margin of the acetabular fossa in a dog with chronic hip dysplasia. The femoral head is seen in the lower left with the acetabular articular surface curving across the top of the image. The area of osteophyte is the depressed area of slightly darker tissue in the center of the arc of acetabular cartilage in the top center of the picture. The acetabular fossa is below this area of osteophyte with frayed round ligament in the lower right. The telescope is looking medially from a lateral portal with dorsal up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5  ­Diseases of the Hip Diagnosed and Managed with Arthroscop

s­ ubluxation are seen as a roughened cartilage surface (Figure  6.23), loss of dorsal acetabular rim cartilage, and bone secondary to wear from subluxation of the femoral head (Figure  6.27). Minor loss does not pre-

clude surgery but extensive loss decreases the area for femoral head support after acetabular repositioning. Dorsal soft tissue damage is typical of chronic hip subluxation with joint capsule changes, and avulsion of

Figure 6.26  A raised more typical osteophyte filling the center of the image at the ventral margin of the acetabular fossa in a dog with chronic hip dysplasia. A small portion of the femoral head is seen at the top of the picture. The telescope is looking medially from a lateral portal and dorsal is down on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.28  Minor avulsion of the dorsal cartilage labrum on the dorsal margin of the acetabulum in a young dog with hip subluxation. The acetabular labrum and joint capsule are seen across the top of the picture and have been displaced into a dorsoventral orientation rather than extending laterally from the bone. There is a short, frayed area at the left end of the acetabular rim where the labrum is tearing away from the acetabulum. A small portion of the femoral head is seen in the bottom of the image and smooth normal appearing acetabular articular cartilage is visible across the center of the picture. The telescope is looking medially from a lateral picture and dorsal is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.27  Cartilage and structural bone loss from the dorsal portion of the acetabular rim in a dog with severe hip dysplasia and secondary to subluxation of the femoral head. The horizontal band of white across the center of the image is the remaining acetabular cartilage with the band of tan tissue below that is exposed bone where cartilage and bone have been worn away by the displaced femoral head. Damaged joint capsule and labrum are visible at the very bottom of the image. The acetabular fossa is seen in the center background and a small portion of femoral head is at the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.29  Avulsion of a major portion of the dorsal labrum off the acetabulum with loss of cartilage and bone from the dorsal acetabulum in a young dog with hip dysplasia. The damaged labrum is seen as the irregular white frayed tissue across the bottom right of the image with exposed bone of the acetabular rim to its left and residual acetabular cartilage beyond the exposed bone in the background. The medial aspect of the femoral head is seen at the top of the image. The telescope is looking medially from a lateral portal and dorsal is down in the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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the dorsal labrum from the acetabular rim that can be minor (Figure  6.28) or major (Figure  6.29) with the frayed appearance of the previous two figures or fractured cartilage (Figure  6.30). There can also be labrum damage without significant avulsion that can

also be minor (Figure  6.31) or major (Figure  6.32). The round ligament is typically damaged with minor partial rupture (Figure  6.33), major partial rupture (Figure  6.34), to complete rupture (Figure  6.20) by the subluxation process. Injuries to this ligament

Figure 6.30  Avulsion of the dorsal labrum of the acetabulum with fracture of the cartilage rather than avulsion with the frayed appearance of the previous two figures. The acetabular cartilage is at the bottom of the image with labrum and joint capsule at the top. The telescope is looking medially from a lateral portal and dorsal is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.32  Major damage to the dorsal labrum of the acetabulum without avulsion. The frayed labrum is seen on the far right with the acetabular articular surface to its left and the acetabular fossa to the far left. The Telescope is looking craniomedially from a lateral portal with dorsal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.31  Minor damage of the dorsal labrum of the acetabulum without any indication of avulsion. In this image it can be seen that the labrum extends lateral to the rim of the acetabular bone to extend the depth of the acetabulum. This differs from the labrum displacement seen in Figure 6.28. The telescope is looking cranially from a lateral portal with dorsal to the right and lateral up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.33  Minor partial rupture of the round ligament in a young dog with hip dysplasia. The round ligament is frayed but essentially intact. The femoral head is on the upper left with the acetabulum to the lower right and the round ligament in the center of the image. There is mild synovitis present. The telescope is looking medially from a lateral portal and dorsal is the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5  ­Diseases of the Hip Diagnosed and Managed with Arthroscop

remodel with chronicity as apparent attempts to heal (Figure  6.35), blunting and resorption of ruptured ligament strands (Figure 6.18), and complete resorption of the damaged ligament (Figure  6.36). Villus synovial proliferation is common involving the round ligament (Figure  6.37), the dorsal joint capsule

Figure 6.34  Significant partial rupture of the round ligament in a dog with chronic hip dysplasia. The ruptured ligament has the appearance of a frayed rope similar to what is seen with cruciate ligament ruptures. The telescope is looking medially from a lateral portal with dorsal to the upper right. The femoral head fills the lower left of the image with the acetabulum to the upper right and the damaged round ligament in the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.35  Remodeling of a partially ruptured round ligament with increased vascularity as an apparent attempt to heal. The femoral head is seen at the top with the acetabular fossa at the bottom and the round ligament filling the center of the image. The telescope is looking medially from a lateral portal and dorsal is down. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure  6.38), the ventral joint space (Figure  6.39), and at the margins of the joint surfaces (Figure 6.40). Vascular pannus is also seen on articular cartilage surfaces (Figure 6.41) indicating lack of normal contact and on the cartilage surfaces of osteophytes (Figure 6.42).

Figure 6.36  The acetabular fossa following complete resorption of the round ligament. The acetabular fossa fills the center of the image extending from right to left with no residual round ligament tissue and an osteophytes visible filling the acetabular fossa. A small portion of femoral head is seen at the top with a small area of acetabular cartilage at the bottom. The telescope is looking medially from a lateral portal and dorsal is at the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.37  Fronds of villus synovial reaction involving round ligament remnants in the hip of a dog with dysplasia. The telescope is looking medially from a lateral portal with dorsal at the bottom. The femoral head is at the top with the acetabulum in the background at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 6.38  Extensive villus synovitis involving the craniodorsal joint capsule in a dysplastic hip joint. The telescope is looking craniomedially from a lateral portal with dorsal to the right. The femoral head is to the left and the acetabular rim is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.41  Pannus seen as fine blood vessels on the caudal margin of the acetabular articular surface and on the dorsal margin of the femoral head articular surface in a young dog with hip dysplasia. The acetabulum is to the lower left with the femoral head on the right. The telescope is looking caudomedially from a lateral portal and dorsal is to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.39  Villus synovitis in the ventral joint space in a young dog with hip dysplasia. The femoral head fills the top of the picture with an indistinct synovial reaction covered transvers acetabular ligament in the lower right. The telescope is looking medially from a lateral portal and dorsal is down in the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.42  Vascular pannus on the cartilage surface of osteophytes on the ventral margin of the acetabulum in a dysplastic hip joint. The telescope is looking medially from a lateral portal and dorsal is to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5.2  Arthroliths Figure 6.40  Villus synovitis on the periphery of the cranial acetabular articular surface on the right with villus synovial proliferation also present on the left in the area of the ruptured round ligament. The telescope is looking craniomedial from a lateral portal and dorsal is down. A small portion of femoral head is in the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Free joint bodies are uncommon in the hip joint but can be seen in older dogs with chronic degenerative changes, typically from hip dysplasia, but the site of origin is not identifiable in most cases (Figure 6.43). These free bodies are removed with arthroscopy.

6.5  ­Diseases of the Hip Diagnosed and Managed with Arthroscop

6.5.3  Soft Tissue Injuries of the Hip Joint Acute soft tissue injuries can occur to the hip joint secondary to traumatic subluxation or luxation in the otherwise anatomically normal hip joint. Cases of traumatic subluxation typically present as an acute onset of hind leg lameness with variable hip pain and no other ­orthopedic findings. These cases present a diagnostic

Figure 6.43  A free osseous joint body in the acetabular fossa of an older dog with chronic hip dysplasia. The telescope is looking medially from a lateral portal with dorsal at the bottom of the image. The femoral head is seen at the top with the acetabulum in the lower left. The site of origin could not be identified in this joint. This arthrolith was removed with arthroscopy. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.44  An acute tear of the dorsal joint capsule in a dog with acute onset lameness, hip pain, and normal hip radiographs. This is a subluxation injury without complete dislocation of the joint. The margin of the joint capsule is seen across the top of the image, the tear with exposed periarticular tissue extends across the center from left to right, and a small remnant of joint capsule is also seen at the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

challenge, and arthroscopy is required to define the injury. Findings in these cases are typically an acute tear (Figure 6.44) in the dorsal joint capsule or granulation tissue filling the dorsal joint capsule injury in chronic cases (Figure 6.45). Round ligament damage is also seen commonly with these injuries with acute minor changes (Figure  6.46), acute severe changes (Figure  6.47), and

Figure 6.45  Granulation tissue filling a dorsal hip joint capsule injury in a dog that presented with a hind leg lameness, hip joint pain, and normal hips on radiographs. The femoral head is seen in the lower right with a band of granulation tissue to the upper right and the joint capsule to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.46  Round ligament changes in a case of traumatic hip subluxation. The telescope is looking medially from a lateral telescope portal with dorsal up on the image. The acetabulum is seen arcing across the top of the image with the femoral head at the bottom and the injured round ligament covered with synovial reaction in the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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chronic changes more typical of those seen with hip dysplasia (Figure 6.48). With the common incidence of partial cruciate ligament injuries that cause hind leg lameness, hip arthroscopy in these subluxation cases is usually combined with stifle arthroscopy to rule out stifle involvement as the cause of lameness. Full hip luxation produces similar but more severe joint capsule (Figure 6.49) and round ligament changes (Figures 6.50 and 6.51) when compared to subluxation cases.

Figure 6.49  Joint capsule damage in a case of complete hip luxation. The hole in the joint capsule in the center of the image is the laceration through which the femoral head passed at the time of luxation. A small portion of the femoral head is seen I the lower left of the image and the joint capsule fills the remainder of the picture. The telescope is looking medially from a lateral portal and dorsal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.47  Severe round ligament damage seen in the same hip as Figure 6.44. The femoral head is on the left with the acetabulum on the right and the injured round ligament in the center of the image. The telescope is looking medially from a lateral portal and dorsal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.50  The ruptured end of the round ligament in the acetabular fossa from the case in the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.48  Round ligament changes in a hip with a subluxation injury that are more typical of the changes seen with hip dysplasia. This dog had an acute onset of hind leg lameness, hip pain, and normal hip radiographs. The telescope is looking medially from a lateral portal and dorsal is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.51  Remnants of the round ligament attached to the fovea capitis of the femoral head from the case in the previous two images. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5  ­Diseases of the Hip Diagnosed and Managed with Arthroscop

6.5.4  Assisted Intra-Articular Fracture Repair Visualization of the acetabular articular surface to assist fracture reductions facilitates acetabular fracture repair. The technique is typically done through the open approach to the joint that is performed with exposure for fracture reduction and implant placement (Figure 6.52). The joint capsule is commonly sufficiently damaged to preclude closed arthroscopy, but additional

Figure 6.52  An acetabular fracture see during arthroscopic assisted fracture repair. The telescope is looking medially through a lateral incision for approach to the hip joint. The acetabulum is on the right with the fracture line in the upper right of the image and the femoral head is on the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.53  Dorsal joint capsule injury with acute and chronic changes in a hip joint with an old acetabular fracture that had not been treated at the time of injury. The injured joint capsule fills the picture and there are no other identifiable structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

joint capsule incision can be avoided with better visualization than can be achieved by open technique. A case with a chronic acetabular fracture that had not been reduced or stabilized at the time of injury was assessed using arthroscopy to determine whether surgery at the time of presentation was indicated. The fracture was adequately healed but residual soft tissue damage involving the dorsal joint capsule (Figure 6.53), round ligament (Figures  6.54 and  6.55), and degenerative changes (Figure 6.56) was seen.

Figure 6.54  The acetabular fossa with complete resorption of the round ligament and a free band of cartilage across the dorsal aspect of the acetabular fossa in the case from the previous figure. The acetabulum is seen as a rim of white tissue around the periphery of the left side of the picture. The rest of the image is the acetabular fossa. The telescope is looking medially from a lateral portal with dorsal to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.55  Resecting the free cartilage band from the acetabular fossa seen in the previous figure using 2.0mm rongeurs. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 6.56  Osteophytes on the cranial margin of the acetabular articular surface in a case with a chronic untreated hip fracture. The femoral head is seen on the left with the acetabulum on the right and the cranial joint capsule at the top of the image. The telescope is looking medially from a lateral telescope portal with dorsal to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 6.57  Neoplastic tissue in the acetabular fossa of a dog with lameness, hip joint pain, and normal radiographs. The telescope is looking medially from a lateral portal with dorsal down in the image. A femoral head is seen at the top of the picture with tumor tissue filling the remainder of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

6.5.5  Biopsy of Intra-Articular Neoplasia Intra-articular neoplastic masses have been found with arthroscopy during hip exploration in cases of hind leg lameness and hip pain that do not have radiographic changes (Figure  6.57). Arthroscopy can also be employed to obtain biopsies of femoral head or periarticular pelvic lesions seen on radiographs, and in many cases, this will be the least traumatic approach for obtaining tissue samples.

6.5.6  Aseptic Necrosis of the Femoral Head The extent of femoral head pathology can be assessed with arthroscopy, even in small dogs, prior to performing femoral head and neck excision (Figure 6.58).

Figure 6.58  The collapsed femoral head in a dog with aseptic necrosis. The irregular femoral head fills the top of the picture with joint space in the lower background. The telescope is looking medially from a lateral portal with dorsal down on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­References Devesa, V. & Rovesti, GL. et al. (2014) Evaluation of a joint distractor to facilitate arthroscopy of the hip joint in dogs. J. Small Anim. Pract. 55: 603–8. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Holsworth, IG. & Schulz, KS. et al. (2005) Comparison of arthroscopic and radiographic abnormalities in the hip joints of juvenile dogs with hip dysplasia. J. Am. Vet. Med. Assoc. 227, 1087–94.

Luther, JF. & Cook, JL. et al. 2005 Arthroscopic exploration and biopsy for diagnosis of septic arthritis and osteomyelitis of the coxofemoral joint in a dog. Vet. Comp. Orthop. Traumatol. 18(1), 47–51. Segal, U. & Shani, J. et al. (2018) Minimally invasive technique for coxofemoral luxation stabilisation using transarticular toggle system: a cadaveric study. J. Small Anim. Pract. 59.154–60.

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7 Stifle Joint Arthroscopy of the stifle joint is indicated when there is hind leg lameness in the presence of stifle pain, crepitus, swelling, or thickening, with or without drawer instability; or when there are abnormal radiographic findings. The most common condition of the stifle joint is injury to the cranial cruciate ligament, and arthroscopy is ideally suited for diagnosing and managing cruciate ligament injuries. Arthroscopy has greatly increased our knowledge of cranial cruciate ligament disease and has enhanced our ability to diagnose this condition, especially in our ability to make early diagnoses. Increased intra-articular fluid density in the cranial joint space of the stifle on a lateral radiograph (Figure 7.1), even in the absence of any physical findings, is sufficient indication for stifle joint arthroscopy and a very high percentage of these cases have partial tears of the cranial cruciate ligament. Another radiographic abnormality strongly correlated to cruciate ligament disease are clusters of focal radio-lucent areas in the inter-condyloid fossa on anterior–posterior views of the stifle (Figure 7.2). These focal areas of radio-lucency are also occasionally seen in the area of insertion of the cranial cruciate ligament in the proximal tibia on lateral radiographs (Figure 7.3). The correlation of these radiographic abnormalities with early cranial cruciate ligament injuries was made by performing arthroscopy on dogs with hind leg lameness physical findings that did not support a diagnosis of cranial cruciate ligament injury. If drawer instability is present, it is diagnostically significant, but the absence of drawer instability is not sufficient to rule out cranial cruciate ligament injury as many dogs with hind leg lameness without drawer instability have early partial tears of the cranial cruciate ligament. Cruciate ligament disease is a chronic insidious process, and true acute cranial cruciate ligament injuries are unusual. The vast majority of “acute” presentations have changes on physical examination, in radiographs, and that are seen with arthroscopy to indi-

cate chronicity of months or years duration. Cranial cruciate ligament injuries are also being recognized more and more commonly as a bilateral condition and assessment of the contralateral stifle is indicated when dogs are undergoing evaluation, arthroscopy, and surgery for the symptomatic stifle (Fuller et  al.  2014). A minimum of a lateral radiograph of the contralateral stifle is indicated. Meniscal injuries are commonly seen with cranial cruciate ligament ruptures (Ertelt and Fehr 2009; Fehr et  al.  1996; Gleason et  al.  2020; Kaufman et  al.  2017; Mccready and Ness 2016a, b; Neal et al. 2015; Plesman et al. 2013; Pozzi et al. 2008; Ralphs and Whitney 2002; Ritzo et al. 2014; Wustefeld-Janssens et al. 2016) but are very rare in the presence of normal cruciate ligaments (Adams et al. 2018; Ridge 2006). The authors personal experience with one case of what was diagnosed at the time as an isolated meniscal injury is now, with additional experience, thought to be in error and an early partial cranial cruciate ligament was missed. Damage to the caudal pole of the medial meniscus is the classic concept of meniscal damage with bucket handle tears, parrot beak tears, cranial folding with entrapment, and crushing commonly described. Arthroscopy has revealed multiple types of injuries encompassing all classifications of meniscal damage and involving both the medial and lateral meniscuses. Lateral meniscal injury has been found to be more common than medial meniscal damage. Fraying of the axial margin of the cranial third of the lateral meniscus is the most frequent finding but bucket handle tears, parrot beak tears, and crushing are also seen. Injuries to other soft tissue structures in the stifle joint are uncommon, especially when compared to cranial cruciate ligament injuries. Injuries to the caudal cruciate ligament are uncommon and are difficult to differentiate from cranial cruciate ligament injuries without arthroscopy. The frequency of caudal cruciate ligament injury diagnosis is also decreasing with improved

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

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Figure 7.1  A lateral radiographic projection of the stifle joint with increased intra-articular fluid density in the cranial joint space indicative of a cranial cruciate ligament injury. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.2  An anterior–posterior radiographic projection of a stifle showing focal radio-lucencies in the inter-condyloid fossa indicative of cranial cruciate ligament injury. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.3  A lateral radiographic projection of a stifle joint showing a focal radio-lucency in the proximal tibial tuberosity indicative of cranial cruciate ligament injury. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

arthroscopic technique allowing earlier diagnosis of minimally damaged cranial cruciate ligaments and the recognition of variations in normal surface appearance of the caudal cruciate ligament. Long digital tendon ruptures or avulsions are seen as a source of lameness originating from the stifle joint but are uncommon. Popliteal tendon avulsions have also been diagnosed as a source of hind leg lameness but are rare. Specific radiographic changes allowing diagnosis of OCD, patellar luxation, patellar fractures, intra-articular fractures of the distal femur or proximal tibia, and periarticular or intra-articular neoplasia can provide a diagnosis before arthroscopy. Radiographic changes indicating degenerative joint disease are nonspecific but are more commonly associated with cranial cruciate ligament injuries than with any other diagnosis. A definitive diagnosis based on radiographs is not possible or necessary, but these changes are an indication for arthroscopy. Preoperative CT or MRI may be beneficial in some cases but do not provide as much information as can be achieved with arthroscopy. Cranial cruciate ligament injuries are the most misdiagnosed and underdiagnosed disease seen in referred patients in the authors’ experience. Diagnosis of earlier more subtle cruciate ligament injuries has become possible using arthroscopy (Ashour et  al.  2019; Bleedorn et  al.  2011; Fuller et  al.  2014). It is not just that

7  Stifle Joint

arthroscopy allows diagnosis of cruciate ligament injuries before they can be diagnosed with any other technique, but clients are more willing to allow arthroscopy to confirm a diagnosis than they are to allow open surgery. Earlier joint examination achieved before chronic changes can be seen with less sophisticated techniques provides an opportunity to achieve better results. Application of the information gained through arthroscopy to reevaluation of history, physical findings, and radiographs has improved interpretation of findings allowing suspicion of cruciate ligament injuries with more subtle changes. The most important conclusion from this process is that increased intra-articular fluid density or displacement of the fat pad on a lateral radiograph of the stifle is the earliest consistent indication of cruciate ligament injury with greater than 90% correlation (Figure 7.1). This is consistently seen before bony changes on radiographs, before palpable joint thickening, before medial buttress formation, before detectable drawer instability, and even when there is no pain response to joint manipulation. Stifle arthroscopy was initially used as a diagnostic tool (Kivumbi and Bennett 1981; Siemering 1978; Van Gestel 1985) but currently is the mainstay of stifle surgery with the intra-articular portion of cruciate ligament surgeries being performed with arthroscopy. The remnants of completely ruptured cranial cruciate ligaments are removed, and the damaged portion of partial tears is debrided with arthroscopy. Any meniscal injuries are addressed with partial meniscectomy under arthroscopic guidance. After completion of arthroscopic management of intra-articular structures, a TPLO is performed as an open procedure without arthrotomy and with open exposure limited to the proximal tibia. This approach improves intra-articular assessment of the joint, improves joint debridement, decreases postoperative pain, and shortens recovery times (Hoelzler et al. 2004; Plesman et al. 2013; Pozzi et al. 2008; Ritzo et al. 2014). Arthroscopic stifle debridement has also been performed as the sole treatment for complete cruciate ligament ruptures. The remnants of the cranial cruciate ligament are removed, the caudal attachment of the medial meniscus is released, and the joint is left unstable. This approach has only been applied with complete ruptures of the cranial cruciate ligament in geriatric patients where recovery from a TPLO is a major portion of their remaining life expectancy. Pain is typically reduced dramatically, and recovery times are days to weeks rather than months. This approach was attempted in younger dogs when owners could not or would not enforce the postoperative activity restriction required

for a TPLO or other cruciate repair procedures. Shortterm results of this approach in young dogs were good, but long-term results were poor with extensive degenerative changes and poor limb function requiring surgical stabilization of the joint at a later time. Arthroscopy is also used to release the medial meniscus by transection of the caudal tibial ligament of the medial meniscus. There is extensive disagreement on the benefits vs detriments of medial meniscal release. There is not adequate science to answer the question to release or to not release. It is agreed that releasing the medial meniscus changes the mechanics of the stifle joint. That is not the question. The question is, does releasing the medial meniscus produce better or worse long-term results than when the meniscus is not released. Any and all of the surgical procedures that are done for cruciate ligament ruptures change the mechanics of the stifle joint. The effects of changes in the mechanics of the stifle joint from the various surgical procedures have not been appropriately studied to be able to differentiate postoperative degenerative changes caused by meniscal release versus those present prior to surgery and those caused by the surgical correction. Extensive degenerative changes are commonly present at the time of diagnoses of most cruciate ligament injuries, and it is unreasonable to expect that the damage will disappear or significantly improve following surgery. Degenerative changes will still be present and may progress. Attributing degenerative changes to meniscal release is not scientifically based. The argument for meniscal release does not apply to all joints and to all meniscal release techniques. The original release technique performed with TPLO surgery using a radial midbody meniscotomy violates the principles of meniscal surgery and is not recommended (Video 7.1), whereas transecting the caudal tibial ligament of the medial meniscus leaves the meniscal body intact and reduces the impact of losing the mechanical support of a normal meniscus. If we accept that meniscal release may reduce joint pain or the risk of future meniscal injury then the question is, when is meniscal release indicated and when is it not indicated. If there is a complete rupture of the cranial cruciate ligament with significant instability of the joint, then there is arguably an indication for meniscal release. If there is an early partial tear of the cranial cruciate ligament with a significant portion of the ligament remaining intact and minimal or no instability releasing the meniscus is not indicated. Second-look arthroscopy in cases of partial cruciate ligament injuries that had a TPLO have shown that with removal of the repetitive tibial thrust stress during weight-bearing the ligament can heal. When this

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happens, the end result is a normal or nearly normal joint. This is the ideal result for cranial cruciate ligament injuries. Case selection is a critical factor in the argument about meniscal release. There is no scientific information available to use for case selection. A criterium that the author has used for this decision has been simple. If there is sufficient instability of the joint that access to the caudal meniscotibial ligament of the medial meniscus is easy and can be achieved without the aid of a stifle distractor then the meniscus is released. The meniscus is released by transection of the caudal meniscotibial ligament of the medial meniscus. If there is sufficient damage to the caudal pole of the meniscus requiring a partial meniscectomy, the ligament is cut as part of the meniscectomy. If there is not sufficient instability to allow easy access to the caudal meniscotibial ligament of the medial meniscus then the meniscus is not released. The other factor needed to achieve the best possible long-term results with cruciate ligament injuries is early intervention. It is ideal to perform corrective surgery before there are any degenerative changes in the joint. Since most cruciate ligament injuries have historically been diagnosed based on the classic physical examination findings of joint pain, joint swelling or thickening, medial buttress formation, and joint instability they are chronic at the time of diagnosis. If we change the approach and pursue all hind leg lameness in dogs as a cruciate ligament injury until proven otherwise and use the information gained from arthroscopy, we can achieve early diagnoses with the potential of improved long-term results. Stifle arthroscopy has almost exclusively been performed in dogs, but it has also been used in cats for diagnosis and management of cranial cruciate ligament injuries (Mindner et  al.  2016; Ruthrauff et  al.  2011), OCD (Bright 2010), and patellar fractures (Cusack and Johnson 2013).

7.1 ­Patient Preparation, Positioning, and Operating Room Setup Since cranial cruciate ligament injuries are the most common finding in the stifle joint, the patient is typically positioned with the leg suspended, prepared, and draped for the surgeon’s preferred cruciate ligament procedure. If there is a specific preoperative diagnosis other than cruciate ligament disease, then this protocol

does not need to be followed but is still based on the intended surgery. For unilateral stifle arthroscopy, the patient is placed in either lateral or dorsal recumbency although dorsal recumbency is preferred with the leg extended caudally as this provides more flexibility for manipulations needed to perform a complete arthroscopic examination of the stifle. If the patient is placed in dorsal recumbency, the monitor is placed at the head of the table, the surgeon stands at the foot of the table at the distal end of the limb, and the assistant stands lateral to the joint being evaluated (Figure  2.9). Alternatively, the monitor can be placed on either side of the table facing caudally and far enough cranially to be out of the way of the aseptic field. If the patient is placed in lateral recumbency, the monitor is placed dorsal to the patient, the surgeon stands ventral to the patient at the distal end of the leg being evaluated, and the assistant stands at the foot of the table (Figure 2.10). Stifle arthroscopy is most commonly performed as a unilateral procedure, but bilateral stifle arthroscopy is also performed and is indicated for bilateral OCD and for bilateral complete cranial cruciate ligament ruptures when bilateral corrective procedures are planned at the same surgery. Bilateral stifle arthroscopy is performed with the patient in dorsal recumbency with the monitor, surgeon, and assistant positioned as for unilateral stifle arthroscopy with the patient in dorsal recumbency (Figure 2.9). Bilateral stifle arthroscopy procedures are well tolerated by the patient.

7.2 ­Portal Sites and Portal Placement 7.2.1  Telescope Portal The standard telescope portal for the stifle joint is on the cranial aspect of the joint either medial or lateral to the patellar tendon and can be placed anywhere between the distal end of the patella and the tibial plateau. The most common portal position for diagnostic joint examination and for operative procedures involving the cranial cruciate ligament, menisci, and femoral OCD lesions is with the telescope portal medial to the patellar tendon and halfway between the distal end of the patella and the tibial crest (Figure 7.4). This puts the portal at the top of the fat pad and greatly facilitates entry into and examination of the joint. Another commonly used telescope portal is placed lateral to the insertion of the patellar tendon just above the tibial plateau between the patellar tendon and “Gerdy’s tubercle. This location

7.2  ­Portal Sites and Portal Placemen

7.2.2  Operative Portals The operative portal is placed on the side of the patellar tendon not used for the telescope portal and typically is placed at the same level as the telescope portal (Figure  7.4). The technique for placing an operative portal using a needle seen inside the joint is not used for the stifle joint, because the fat pad and the extensive villus synovial proliferation occurring with cruciate ligament injuries obscures visualization. Operative portal location in the stifle joint is determined with sufficient accuracy by external landmarks so this technique is not needed. To place the operative portal, a stab incision is made into the joint at the portal site with a no. 11 scalpel blade. A curved mosquito hemostat or the initial operative instrument is worked into the joint with blunt dissection until it is visualized with the telescope.

7.2.3  Egress Portal Figure 7.4  Portal sites on the cranial aspect of the stifle joint. The three portals shown are the craniomedial telescope portal (asterisk), the craniolateral operative portal (square), and the suprapatellar egress portal (X). The telescope portal is placed halfway between the distal end of the patella and the proximal end of the tibial crest just medial to the patellar tendon. The operative portal is placed at the same level as the telescope portal and just lateral to the patellar tendon. The egress portal is placed in the suprapatellar pouch of the joint. Source: Modified from Freeman (1999) © John Wiley & Sons.

is reported to provide superior visualization of the meniscuses and facilitate operative procedures. The disadvantage of this portal site is that the telescope is placed into the fat pad. A telescope portal can also be placed immediately distal to the patella. This site keeps the telescope away from the fat pad and facilitates examination of the cranial compartment of the joint including the insertions of the cruciate ligaments but access to the menisci is limited. To place the telescope portal, a 20 gauge 1.5” hypodermic needle is placed into the joint at the operative portal site and joint fluid is aspirated (Figure  2.11), the joint is distended with saline (Figure 2.12), a stab incision is made into the joint with a no. 11 scalpel blade at the telescope portal site, and the telescope cannula with the blunt obturator is inserted into the joint (Figure  2.13) directed caudally initially and then is directed proximally into the lateral aspect of the suprapatellar pouch (Figure 7.5). The telescope portal can also be placed lateral to the patellar tendon with the operative portal medial to the tendon.

An egress cannula is routinely used for both diagnostic and operative stifle arthroscopy. Minor diagnostic procedures can be performed without an egress cannula but with the extent of villus synovial reaction seen with cruciate ligament injuries, and the need for its removal to allow adequate joint examination, effective egress is required. The suprapatellar pouch is the most practical site for an egress portal in stifle joint arthroscopy (Figure  7.4). This location is out of the way of diagnostic examination or operative procedures and is easier to maintain a cannula at this site. The egress cannula is placed using the telescope cannula at the time of its initial insertion typically before placement of the telescope. Once in the joint the tip of the telescope cannula is positioned into the lateral aspect of the suprapatellar pouch, and the blunt obturator is removed (Figure 7.5). The blunt obturator is replaced with the sharp trocar, and the sharp trocar with the cannula is pushed out through the joint capsule and skin (Figure 7.6). The sharp trocar is removed, and the egress cannula is inserted into the tip of the telescope cannula (Figure 7.7). The telescope cannula is retracted back into the joint with the egress cannula (Figure 7.8). Once the tip of the egress cannula is inside the joint, it is backed out of the telescope cannula until the two cannulas are separated. The egress cannula is positioned in the lateral joint space, its position is confirmed visually in both normal (Figure  7.9) and abnormal joints (Figure 7.10), and it is inserted as far as possible. This is a fast, easy, and trouble-free method of egress cannula placement.

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Figure 7.5  Once the telescope cannula is in the joint, with the blunt obturator in place, it is positioned with its tip in the lateral aspect of the suprapatellar pouch. The blunt obturator is removed and replaced with the sharp trocar to allow placement of an egress cannula. Source: Modified from Freeman (1999) © John Wiley & Sons.

Figure 7.6  The sharp trocar is inserted into the telescope cannula and locked in place. The sharp trocar and cannula are pushed in a proximal direction out through the joint capsule, subcutaneous tissue, and skin. Source: Modified from Freeman (1999) © John Wiley & Sons.

Figure 7.7  The sharp trocar is removed, and the egress cannula is inserted into the tip of the telescope cannula. Source: Modified from Freeman (1999) © John Wiley & Sons.

Figure 7.8  The tip of the telescope cannula is retracted back into the joint with the egress cannula. Inside the joint, the egress cannula is backed out of the telescope cannula until they are separated. The egress cannula is then positioned in the lateral joint space. Source: Modified from Freeman (1999) © John Wiley & Sons.

7.4  ­Examination Protocol and Normal Arthroscopic Anatom

the switching stick, and the telescope cannula is retracted back into the joint with the switching stick and egress cannula, and the switching stick is removed freeing the egress cannula in the joint. The egress cannula is positioned in the lateral joint space and is inserted as far as possible. This is also a fast, easy, and trouble-free method of egress cannula placement.

7.3 ­Nerves of Concern with Stifle Joint Arthroscopy

Figure 7.9  An egress cannula positioned in the lateral joint space in a normal left stifle joint without villus synovitis. The telescope is looking proximally and laterally from a craniomedial portal into the lateral joint space to visualize the egress cannula in position. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.10  A more typical appearance of an egress cannula in the lateral joint space obscured by villus synovitis secondary to a ruptured right cranial cruciate ligament. The egress cannula is partially visible in the lateral joint compartment with the telescope looking proximally and laterally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

A similar technique for egress cannula placement is used if the egress cannula is too large to fit within the telescope cannula. This technique uses a changing rod or a switching stick. The tip of the telescope cannula is positioned in the lateral aspect of the suprapatellar pouch and is pushed out through the skin with the sharp trocar as previously described. The sharp trocar is removed, a switching stick is placed into the distal end of the telescope cannula so that it protrudes through the cannulas proximal end, an egress cannula is placed over

There are no significant nerves at risk with placement of the current craniomedial, craniolateral, and suprapatellar stifle joint portals (Figure  7.4) as all nerves are caudal to the joint.

7.4 ­Examination Protocol and Normal Arthroscopic Anatomy The stifle joint is the most difficult of all the joints to examine effectively. This difficulty is due to the stifle’s complex anatomy, the presence of the fat pad in the cranial compartment of the joint, and because of the extensive villus synovial reaction that occurs with cranial cruciate ligament injuries. Stifle joint examination is facilitated by using a consistent systematic approach to visualizing the joint, having adequate fluid pressure and flow, and by using a combination of radio-frequency and a power shaver to remove part of the fat pad and villus synovial tissue to establish an adequate visual field. Examination of the stifle is begun with the tip of the telescope in the suprapatellar pouch. Fluid egress is momentarily arrested to distend the joint for orientation and to improve the visual field. The telescope is retracted distally until the suprapatellar joint space can be seen with identification of the joint capsule (Figure 7.11). If the image is obscured by cloudy joint fluid, the egress port is opened allowing the fluid to drain and then closed to distend the joint. This procedure is repeated until a clear image is achieved. A plica, or horizontal band of tissue, is commonly present in the suprapatellar pouch as a single-centered band seen with the joint fully distended and the caudal surface of the quadriceps tendon visible at the top of the image (Figure  7.12), as a single band adjacent to the quadriceps tendon seen with the stifle joint partially distended (Figure  7.13), or as multiple bands (Figure  7.14). As the telescope is retracted further the caudal articular surface of the proximal end of the patella and the proximal articular

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surface of the trochlear groove come into view (Figure  7.15). The structures seen in the previous figures are used for orientation. During the orientation process, the suprapatellar pouch is examined. Variable accumulations of fat are commonly seen in the suprapatellar pouch (Figure  7.16), and the entry point of the

Figure 7.11  The view with the telescope in the distended suprapatellar pouch looking proximally from a craniomedial portal. The image is almost completely filled with the smooth, almost translucent distended joint capsule. Blood vessels are visible in the joint capsule tissue. The small area of white in the bottom-right edge of the image is the proximal end of the trochlear groove joint cartilage. Cranial is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.12  Orientation in the stifle joint with the tip of the telescope in the suprapatellar pouch looking proximally from a craniomedial portal and cranial is up on the picture. Visible are the joint capsule, a single horizontal band or plica crossing the center of the image, and the caudal surface of the quadriceps tendon at the top of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

egress cannula is identified (Figure 7.17). Once orientation is achieved, continued retraction of the telescope allows visualization of the caudal articular surface of the patella, the cartilage of the trochlear groove, the medial trochlear ridge, and the medial parapatellar fibrocartilage (Figure  7.18). The telescope is directed into the proximal medial compartment of the joint (Figure 7.19), retracted distally in the medial compartment (Figure  7.20), and then transferred to the lateral

Figure 7.13  A partially distended stifle joint with a single horizontal plica in contact with the caudal surface of the quadriceps tendon above the plica. The proximal end of the patella is visible at the top of the image and the trochlear groove at the bottom of the image. Cranial is up on the image with the telescope looking proximally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.14  A normal variation is seen in this patient with multiple plicae in the suprapatellar pouch of a fully distended stifle joint. Telescope position and orientation are the same as the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.4  ­Examination Protocol and Normal Arthroscopic Anatom

compartment (Figure 7.21) for evaluation of the abaxial surfaces of the trochlear ridges and the joint capsule. These areas are examined with the joint in extension. As the tip of the telescope moves distally around the cranial aspect of the femoral condyles, either medial or

Figure 7.15  Retraction of the telescope from the suprapatellar pouch brings the proximal trochlear groove into view at the bottom of the image and caudal surface of the proximal patella at the top of the image. The suprapatellar pouch and the caudal surface of the quadriceps tendon are still visible in the field at the top of the image. Orientation and telescope position are the same as in the previous images. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.16  A normal accumulation of fat visible in the suprapatellar pouch proximal to the trochlear groove articular cartilage. The telescope is looking proximally from a craniomedial portal with cranial up on the image. The proximal extent of the trochlear groove is visible at the bottom with the quadriceps tendon at the top, joint capsule in the background with an indistinct plica, and fat at the bottom center of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

lateral, the joint is flexed. The tip of the telescope can also be moved distally in the trochlear groove after the medial and lateral compartments have been examined. The fat pad is encountered during this portion of the examination and in normal joints can be swept out of the visual field with the tip of the telescope allowing examination of the cranial surface of the femoral condyle. The visual field is commonly lost during this maneuver due to the fat pad. If this occurs, the telescope is repositioned in the medial or lateral joint space and

Figure 7.17  The entry point of the egress cannula seen in the lateral extent of the suprapatellar pouch in a normal joint. Lateral is to the right with cranial up on the image, and the telescope is looking craniolaterally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.18  The trochlear groove is seen at the bottom of the image with the lateral trochlear ridge on the right, the caudal articular surface of the patella at the top, the medial trochlear ridge in the left foreground, and the medial parapatellar fibrocartilage in the background at the top left of the image to the left of the patella. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.19  The proximal end of the medial joint space with joint capsule curving across the top of the image and down the left side with the proximal end of the medial aspect of the medial trochlear ridge to the right. A small accumulation of fat is visible attached to the medial joint capsule. The tip of the telescope has been moved from the trochlear groove into the medial joint space and is looking proximally from a craniomedial portal. Cranial is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.20  Further distally in the medial joint space from the image in the previous figure, the medial surface of the medial trochlear ridge is visible on the right and medial joint capsule is seen on the left side of the image. From the craniomedial portal, the telescope is aligned with the medial joint space allowing easy examination. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the maneuver is repeated until the image is maintained. Examination around the fat pad is much more difficult in the presence of the typical villus synovial reaction seen with cranial cruciate ligament injuries, but cursory examination can still be achieved in some patients (Video 7.2). Partial synovectomy and fat pad resection

Figure 7.21  Lateral joint space with the lateral surface of the lateral trochlear ridge viewed on the left with the telescope angled across the trochlear ridges from the craniomedial telescope portal. Lateral joint capsule is seen filling the right side of the image. Medial is to the left, and cranial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

are needed for effective examination of joints with pathology. The telescope is positioned in the inter-condyloid fossa for evaluation of the cranial and caudal cruciate ligaments (Figure  7.22a). Occasionally, the middle genicular artery is seen in the space between the fat pad and the cruciate ligaments (Figure 7.22b). Visualization of the medial meniscus is achieved by external rotation of the tibia with valgus stress to the stifle to open the medial joint space. The entire meniscus can be examined from the cranial pole (Figure 7.23), moving medially and caudally to visualize the axial margin (Figure 7.24), caudal pole (Figure 7.25), and the caudal meniscotibial ligament of the medial meniscus (Figure 7.26). The lateral meniscus is exposed by varus stress to the stifle, with or without internal rotation, for examination of the cranial pole and cranial portion of the axial margin (Figure 7.27), moving caudally to visualize the caudal portion of the axial margin (Figure 7.28), the caudal pole (Figure 7.29), and the caudal tibial ligament of the lateral meniscus (Figure 7.30). The meniscofemoral ligament of the lateral meniscus can occasionally be seen. If there is significant drawer instability because of a cranial cruciate ligament injury, visualization of the meniscuses is improved by cranial displacement of the proximal tibia. The long digital extensor tendon is identified in the craniolateral joint and is visualized from its origin at the extensor fossa on the abaxial surface of the lateral condyle of the femur to where it exits the joint distally. Its appearance changes

7.4  ­Examination Protocol and Normal Arthroscopic Anatom

(a)

(b)

Figure 7.22  (a) Normal cranial and caudal cruciate ligaments. The cranial cruciate is seen on the left side of the image with the fibers directed toward the telescope. The caudal cruciate ligament is on the right side of the image with the fibers running more vertically. The telescope is looking caudally from a craniomedial telescope portal with proximal or dorsal up on the image and medial is to the right. (b) A view of the cranial joint space with the fat pad displaced ventrally and the middle genicular vessels supplying the fat pad are seen coursing across the center of the image between the caudal surface of the fat pad at the bottom, the craniolateral surface of the medial femoral condyle on the left, and the caudal cruciate ligament deep on the right. The cranial cruciate ligament is not visible as it is buried in the fat pad. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.23  The cranial pole of the medial meniscus is in the lower left of the image with the tibial plateau at the bottom on the right and the medial femoral condyle filling the top half of the image. The telescope is looking caudomedially from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.24  The axial margin of a normal medial meniscus seen on the left side of the joint space crossing the tibial plateau at the bottom. The medial femoral condyle is visible at the top of the image. Undulations present in the free margin are normal and are positional artifacts created by cranial displacement of the tibial plateau relative to the femur. The tip of a 2.0 mm manipulation probe is seen at the far right of the image. The telescope is looking caudomedially from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.25  The caudal pole of the medial meniscus is on the left-center of the image transitioning into the caudal tibial ligament of the medial meniscus on the right-center of the image. The medial femoral condyle is in the upper left of the image, and the tibial plateau is at the bottom of the image. The tip of a 2.0 mm manipulation probe is visible at the far right of the image. The telescope is looking caudomedially from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.26  The caudal tibial ligament of the medial meniscus is seen obliquely crossing the center of the image with the caudal cruciate ligament on the right, the caudolateral corner of the medial femoral condyle on the upper left, and the tibial plateau on the bottom. The transition into the caudal pole of the medial meniscus is seen at the left end of the ligament. The telescope is looking caudally from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.27  The cranial pole and cranial portion of the axial margin of the lateral meniscus is seen on the left of the image between the lateral femoral condyle at the top of the image and the tibial plateau at the bottom. The lateral meniscus is less likely to distort with undulations see in the medial meniscus. The telescope is looking caudolaterally from a craniomedial portal with lateral to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.28  The central and caudal axial margin of the lateral meniscus on the right and deep in the image seen between the lateral femoral condyle in the upper left and the tibial plateau at the bottom. Mild irregularity or fraying of the axial margin seen in this lateral meniscus is not uncommon and is not considered to be clinically significant. The telescope is looking caudolaterally from a craniomedial portal with lateral to the right and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.4  ­Examination Protocol and Normal Arthroscopic Anatom

Figure 7.29  The ventral surface of the caudal pole of the lateral meniscus is crossing the center of the image. The meniscus is being elevated with a 2.0 mm hook probe to assess its ventral surface. The lateral femoral condyle is filling the upper half of the image, and the tibial plateau is on the bottom. The telescope is looking caudally from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

based on position of the joint and the telescope portal being used, from what is seen with the telescope in the craniomedial portal and the joint at a standing position (Figure  7.31), with the joint fully flexed (Figure  7.32), and with the joint fully extended (Figure  7.33). When the telescope is in the craniolateral portal, it is directly over the long digital extensor tendon (Figure 7.34). The proximal tendon of origin of the popliteal muscle is also identified in the lateral compartment of the joint, when the telescope is in the craniolateral portal, and the telescope is passed through the triangular space between the femoral condyle and the long digital extensor tendon (Figure 7.31). The tendon is seen from its origin on the lateral aspect of the lateral femoral condyle as it angles caudally and distally (Figure 7.35) and can be followed as it extends into the caudal joint space (Figure 7.36). The caudal compartment of the stifle joint can also be accessed by passing the telescope through the intercondyloid fossa through the space created by a ruptured cranial cruciate ligament. Placement of the telescope into the caudal joint space using this approach is not attempted when the cruciate ligaments are intact as ligament damage can occur. In the presence of significant stifle pathology with typical villus synovial reaction, visualization of the stifle is greatly facilitated by partial cranial compartment syn-

Figure 7.30  The caudal pole of the lateral meniscus is seen deep to the lateral femoral condyle with the caudal tibial ligament of the lateral meniscus deep on the left side of the image. Most of the axial margin of the lateral meniscus is visible with the tip of the cranial pole indistinctly seen at the right margin of the image. The lateral femoral condyle is at the top of the image, and the caudomedial margin of the tibial plateau is visible in the bottom center of this view. The telescope is looking caudally from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.31  The tendon of origin of the long digital extensor muscle is seen extending distally from its origin on the abaxial surface of the lateral femoral condyle. In this image, the joint is at a normal standing angle and the telescope is looking laterally from the craniomedial portal. The craniolateral aspect of the lateral femoral condyle is on the left side of the image, the long digital extensor tendon is visible crossing the center of the image vertically, and the joint capsule is on the right. Lateral is to the right and dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.32  The tendon of origin of the long digital extensor muscle is seen with the joint fully flexed and with the telescope looking laterally from the craniomedial portal. The tendon is positioned vertically in the center of the image, the femoral condyle is on the left and the lateral joint space is on the right. The surface of the tendon is mildly roughened without the smooth clean surface and easily seen tight fibers seen in the previous image indicating possible early injury. Lateral is to the right, and dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.34  The tendon of origin of the long digital extensor muscle seen with the telescope in the craniolateral portal. Medial is to the right, and proximal or dorsal is up. The lateral femoral condyle is seen on the right side of the image with the tendon filling the left side of the image. A small portion of the abaxial margin of the lateral meniscus and its articulation with the lateral femoral condyle are visible in the lower right of the image cranial to the tendon. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.33  The tendon of origin of the long digital extensor muscle is seen with the joint extended with the telescope looking laterally from the craniomedial portal. The tendon is seen as a vertical structure in the center of the image with the lateral margin of the lateral femoral condyle filling the upper left, the caudal surface of the fat pad at the bottom of the image, and the lateral joint capsule on the right. This tendon does not have a totally normal appearance. Lateral is to the right, and dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.35  The popliteal tendon is seen in the lateral joint space originating from the abaxial surface of the lateral femoral condyle and running caudally and distally within the joint. The tendon is obliquely positioned in the center of the image with the lateral femoral condyle in the upper left, the abaxial surface of the lateral meniscus on the lower left, and the lateral joint capsule on the right. The telescope is looking caudally from a craniolateral portal with dorsal or proximal up and lateral is to the right. To obtain this view, the telescope is passed between the long digital extensor tendon and the femoral condyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.36  The popliteal tendon can be followed caudally as it extends around the caudolateral corner of the joint into the caudal joint compartment. The tendon is seen as it obliquely crosses the upper image with the caudal portion of the lateral femoral condyle on the upper right, the caudal abaxial margin of the lateral meniscus on the lower right, and joint capsule on the left. The joint capsule in this image shows an abnormal appearance with villus ghosts indicating resolved inflammation. The telescope is looking caudally from a craniolateral portal with dorsal or proximal up, and lateral is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

ovectomy and fat pad removal using a combination of radiofrequency and a power shaver before examination of the cruciate ligaments or meniscuses. Extensive villus synovial proliferation is seen with cruciate ligament injuries and since this is the most common diagnosis with arthroscopy of the stifle joint, this is a very important step in the procedure. In normal joints, examination can be completed in most cases without fat pad resection. Radiofrequency in this application has the advantage of sealing blood vessels during tissue removal but has the disadvantage of leaving more debris in the joint (Figure  7.37). The shaver has the advantage of leaving little or no debris in the joint but does not control bleeding. Without hemostasis bleeding obscures, the visual field preventing examination or operative procedures. Thus, the shaver is used primarily to remove avascular tissue such as the fat pad, cruciate ligament, and meniscal tissue. The combination of both instruments minimizes the disadvantages of each and applies the advantages of both.

7.5 ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscopy 7.5.1  Cranial Cruciate Ligament Injuries

Figure 7.37  Debris remaining after using radiofrequency to debride the origin of a ruptured cranial cruciate ligament. The caudal cruciate ligament is visible on the left side of the image, and the lateral surface of the medial femoral condyle is on the right. The irregular dirty tissue in the center of the image is the remaining debrided end surface of the cranial cruciate ligament. The telescope is looking caudolaterally from a craniomedial portal with medial to the left and dorsal or proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Partial or complete rupture of the cranial cruciate ligament is the most common pathology found with arthroscopy in the stifle joint of dogs. The initial finding on entering a stifle joint with cruciate ligament pathology is an extensive villus synovial reaction throughout the joint. Typically this villus reaction is dramatic and is seen in the suprapatellar pouch (Figure  7.38), the medial joint space (Figure 7.39), the lateral joint space (Figure  7.10), the caudal joint compartment (Figure  7.40), and in the cranial joint compartment (Figure 7.41). This villus synovial reaction is present on all synovial surfaces of the joint and is involved in all joint spaces with equal severity. Variation in severity of synovitis is not based on location in the joint but is based on other factors such as chronicity. Mild early synovial reaction is seen in all the above joint spaces (Figures 7.42–7.44). Synovial reaction in the stifle joint of dogs with cranial cruciate ligament injuries also has other less common appearances including smooth nodules (Figure  7.45), nodular roughening with vascular (Figure 7.46) or avascular appearance (Figure 7.47), single nodules (Figure  7.48), large thick smooth synovial projections with vascularity (Figure  7.49) or without apparent blood vessels (Figure 7.50), multiple mass-like

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Figure 7.38  Villus synovial reaction in the suprapatellar pouch of a dog with a cranial cruciate ligament injury. The telescope is looking proximally from a craniomedial portal with medial to the left. There are no anatomically identifiable structures in this picture which is typical in areas of joints with cranial cruciate ligament injuries. Villus reaction in this picture has two different appearances. The villi with obvious blood vessels on the left are originating from the joint capsule and those on the right without visible blood vessels are coming off the periosteum proximal to the trochlear articular cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.40  Villus synovial reaction in the caudal joint compartment of a dog with a cranial cruciate ligament rupture. The telescope is looking caudally through the intercondyloid fossa of the femur from a craniomedial portal. Access to the caudal joint space in this patient was easily achieved because the cranial cruciate ligament was completely ruptured. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

lumps (Figure  7.51), single (Figure  7.52) or multiple (Figure 7.53) large irregular fronds with or without visible vascular supply, low flat areas of synovial thickening (Figure 7.54), and combinations of these formations

Figure 7.39  Typical villus synovial reaction in the medial joint space of a dog with a cranial cruciate ligament rupture. Medial is to the right, and the telescope is looking proximally or dorsally from a craniomedial portal. A ridge of osteophytes is visible in the upper left side of the image with prominent villi containing obvious blood vessels coming off femoral periosteum on the lower left and scattered small villi coming off the joint capsule in the upper right half of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.41  Villus synovial reaction in the cranial joint compartment of a dog with a cranial cruciate ligament rupture. Strands of the ruptured cruciate ligament are seen in the background. The telescope is looking caudally from a craniomedial portal and dorsal or proximal is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure 7.55). The villus synovial reaction seen with cruciate ligament disease, and other joint pathology, is typically very vascular but when the active reaction resolves villus “ghosts” are left behind and are seen in all the areas where villus reaction occurs (Figures  7.56 and 7.57).

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.42  Mild synovial reaction in the suprapatellar pouch in a dog with early partial cranial cruciate ligament rupture. Cranial is up on the image, and the telescope is looking dorsally or proximally from a craniomedial portal. Anatomic structures are still visible and are not obscured with synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.43  Very mild synovial reaction on the joint capsule surface of the medial joint space in a dog with very early partial cranial cruciate ligament rupture. The telescope is looking proximally from a craniomedial portal with cranial up on the image and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.44  Early very mild synovial reaction in the cranial joint space among strands of ruptured cranial cruciate ligament. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up and medial is to the right. The lateral surface of the medial condyle fills the right side of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.45  Scattered nodules of smooth synovial thickening without villi formation in the stifle of a dog with a very early partial cranial cruciate ligament injury. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Synovial membrane petechiae are seen in canine stifle joints with cranial cruciate ligament injuries. These lesions have been observed in the suprapatellar area at the proximal end of the trochlear groove (Figure 7.58), on the distal end of the patella (Figure 7.59), and in the intercondylar fossa (Figure  7.60). Larger more ecchymotic lesions have also been seen (Figure  7.61). The cause and significance of these lesions are unknown.

Vascular pannus is also seen in stifle joints with cranial cruciate ligament disease (Video 2.1). As with petechia, their cause and significance are not known but they are likely a manifestation of synovial proliferation extending over cartilage, ligaments, menisci, and other surfaces. Pannus cannot form on articular cartilage surfaces if there is normal weight-bearing contact as the normal contact forces destroy the blood vessels and

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Figure 7.46  Nodular roughening of the synovium with visible vascularity in the stifle of a dog with a cranial cruciate ligament injury. The telescope is looking proximally in the medial joint space with medial joint capsule on the left and femur on the right obscured by the synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.48  A single small synovial mass in the medial joint space of the stifle joint in a dog with a cranial cruciate ligament injury. The mass is originating from the femoral surface on the left side of the image with variable severity typical villus reaction on the remainder of visible synovial surfaces. The telescope is looking proximally from a craniomedial portal with cranial up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

tissue. This could potentially be a source of joint pain and hemarthrosis. Lesions are seen on articular cartilage surfaces in the proximal trochlear groove (Figure 7.62), on the femoral condyle (Figure 7.63) and on the patella (Figure 7.64). Pannus lesions are also seen on areas other than articular cartilage including the axial surface of the intercondylar fossa (Figure 7.65), on menisci (Figure 7.66), on osteophytes (Figure 7.67), on the long digital extensor tendon (Figures 7.68 and 7.69),

Figure 7.47  Avascular nodular roughening of the synovium in a dog stifle with cranial cruciate ligament disease. The telescope is looking proximally in the medial joint space with the avascular nodular roughening on the femur on the right and more vascular joint capsule in the background to the left. Cranial is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.49  A large smooth vascular synovial projection in the suprapatellar pouch in a dog’s stifle joint with a ruptured cranial cruciate ligament. Multiple synovial masses are also present in the background. Cranial is up on the image, and the telescope is looking proximally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

and on both the cranial (Figures 7.70 and 7.71) and caudal cruciate ligaments (Figure 7.72). The appearance of pannus lesions is affected by intra-articular pressure with increased pressure compressing the blood vessels making them less distinct (Figure 7.73) (Video 2.1). Osteophytes are seen at the margins of articular surfaces as part of degenerative changes secondary to CCL

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.50  A large avascular smooth synovial projection in the suprapatellar pouch of the stifle joint in a dog with a cranial cruciate ligament injury. Villus ghosts are also visible in this image and the avascular appearance of the large lesion may be related to the ghost stage in this stifle. The telescope is looking proximally from a craniomedial portal with cranial up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.52  A single large irregular synovial frond in the suprapatellar pouch of a dog stifle joint with a chronic cranial cruciate ligament injury. The low vascularity of this tissue may indicate resolution of the active phase or may be due to other factors. Villi in the lower left background have more coloration indicating a more active process. The telescope is looking proximally from a craniomedial portal and cranial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.51  Multiple synovial masses in the suprapatellar pouch of the stifle joint in a dog with a chronic cranial cruciate ligament rupture. Some of the masses are white, avascular in appearance and others have a more vascular coloration but no blood vessels are visible. Cranial is up in this picture, and the telescope is looking proximally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.53  Multiple large irregular synovial fronds in the suprapatellar pouch of a stifle joint of a dog with a chronic cranial cruciate ligament rupture. Cranial is up in this picture, and the telescope is looking proximally from a craniomedial portal. Vascularity appears to increase from left to right but the significance of this is unclear. Villi in the background have a red, vascular coloration. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

injuries. A common site for stifle osteophytes is in the suprapatellar pouch extending proximal to the articular surface of the trochlear groove as relatively flat extension of the cartilage surface with varying grades of chondromalacia (Figure  7.74), as multiple irregular rounded bony proliferations with shallow separations

giving a “cobble stone” appearance (Figure 7.75), multiple rounded bony proliferations in the same area with deep grooves separating lesions (Figure 7.76), as a rim of osteophytes around a recessed area without bony proliferation (Figure  7.77), as a transverse ridge of bone proximal to the trochlear groove cartilage (Figure 7.78),

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Figure 7.54  A wide-based flat area of synovial thickening in the suprapatellar pouch at the proximal end of the visible quadriceps tendon of a dog stifle joint with a chronic cranial cruciate ligament injury. There are multiple villus ghosts scattered over the joint capsule surface indicating an inactive process. A plica is partially visible extending across the background of the image. Cranial is up with the telescope looking proximally. The proximal end of trochlear groove cartilage is visible across the bottom of the picture with an area of mildly reactive discolored synovium in the bottom center. Multiple proximal trochlear osteophytes are present across the lower center of the image proximal and abaxial to the bottom center area of synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.56  Villus “ghosts” in the suprapatellar pouch of the stifle of a dog with a cranial cruciate ligament rupture. The telescope is looking proximally from a craniomedial portal and cranial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.57  Villus “ghosts” in the cranial joint compartment of the stifle of a dog with a cranial cruciate ligament injury. Dorsal or proximal is up on the image, and the telescope is looking caudally from a craniomedial portal. Femoral condyle articular cartilage is seen in the background across the top of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc. Figure 7.55  A combination of the previously described synovial changes in the stifle joint in the suprapatellar pouch of a dog with a cranial cruciate ligament rupture. Villi with visible blood vessels, villi without visible vessels, a mass, fronds, and villus ghosts are all present. Cranial is up, and the telescope is looking proximally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

as flat(Figure 7.79) or elevated (Figure 7.80) extensions medially or laterally (Figure 7.81), and as isolated bony elevations (Figure 7.82). Osteophytes also occur on the medial and lateral surfaces of the trochlea at the abaxial

cartilage margins as small low flat ridges of bone (Figure 7.83), as large smooth round ridges (Figure 7.84), and as large irregular round ridges (Figure 7.85) viewed with the telescope positioned in the medial joint space from the craniomedial telescope portal. Medial osteophytes are also seen with the telescope positioned in the trochlear groove or cranial to the medial joint space as large mildly irregular round ridges (Figure 7.86), or as flattened ridges (Figure  7.87). Similar abaxial osteophytes are also seen on the lateral aspect of the femoral trochlea having the same variation in appearance with

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.58  Petechia in the synovial membrane at the proximal end of the trochlea is seen across the bottom of the image in a dog with a cranial cruciate ligament injury. Cranial is up, and the telescope is looking proximally. Villus synovial reaction is present in the suprapatellar pouch in the upper background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.60  Petechia in the synovial membrane on the axial surface of the intercondylar fossa in the stifle of a dog with cranial cruciate ligament disease. The telescope is looking caudally from a craniomedial portal. Proximal or dorsal is up on the picture, and the caudal cruciate ligament is visible on the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.59  Petechia in the synovium at the distal end of the patella in a dog with a cranial cruciate ligament injury. Cranial is up, and the telescope is looking proximally from a craniomedial portal. The distal end of the patella is visible in the center of the image with the caudal articular patellar surface extending into the background in the lower right and the synovial covered caudal surface of the patellar tendon seen across the top of the picture. A small area of parapatellar cartilage is visible on the far left with petechia on its distal surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.61  A larger area of synovial hemorrhage more on the size of an ecchymosis is seen in the synovial tissue at the proximal end of the trochlear groove in the lower left. Cranial is up, and the telescope is looking proximally. The suprapatellar pouch is seen in the upper background with an area of villus reaction. Proximal trochlear groove osteophytes are seen in the center proximal to the area of the ecchymosis and on the trochlear ridge on the right side of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

small (Figure  7.88), large smooth ridges (Figure  7.89), large irregular ridges (Figure 7.90), large irregular clusters (Figure 7.91), and flattened lesions (Figure 7.92). As seen in the previous images, osteophytes on the distal femoral condyle typically occur at the margins of articular cartilage surfaces but they can also occur within the articular cartilage (Figures 7.93 and 7.94). Patellar oste-

ophytes are seen at the proximal end (Figure 7.95), the distal end (Figure 7.96), on the medial (Figure 7.97) or lateral (Figure  7.98) margins, or in multiple locations (Figure  7.99). Osteophytes are less commonly seen on the tibial plateau in the area of the intercondyloid eminence (Figure 7.100) and in the intercondyloid fossa of the femur (Figure  7.101). All the above images show

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Figure 7.62  Vascular pannus extending onto the proximal articular cartilage of the trochlear groove in the stifle of a dog with cranial cruciate ligament disease. Cranial is up, and the telescope is looking proximally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.63  Vascular pannus in a cartilage indentation on the ventral or distal surface of the medial condyle of the femur. The bed of this indentation was covered with normalappearing cartilage. The cause of this lesion is unknown but is in the location typical for OCD. The femoral condyle fills the upper right of the image with tibial plateau across the bottom. The telescope is angled caudomedially from a craniomedial portal with proximal or dorsal up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.64  Vascular pannus on the margin of the articular cartilage of the patella in a dog with a cranial cruciate ligament injury. Cranial is up and proximal is to the right with the telescope looking at the medial surface of the patella from a craniomedial portal. The patella fills the upper portion of the picture, and the trochlear groove articular cartilage is visible in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.65  Vascular pannus on multiple structures including the axial surface of the intercondylar fossa of the femur on the left and the caudal cruciate ligament on the right. This is seen in the stifle joint of a dog with a cranial cruciate ligament rupture. Proximal is up, and the telescope is looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

hard osteophytes comprised of bone in various sizes, locations, and configurations and it has always been assumed that osteophytes form as bone at their origin and throughout their growth. One case was seen with soft tissue formations in the area on the abaxial surface of the femoral condyle where osteophytes typically form (Figure  7.102) suggesting the possibility that osteo-

phytes originate as soft tissue that becomes bone with maturation. Cartilage lesions seen with cranial cruciate ligament disease include all grades of chondromalacia (Table 3.1) and are seen on all articular cartilage surfaces throughout the joint. Mild or Grade I chondromalacia has been seen as single blisters on the femoral condyles (Figure 7.103) and in the trochlear groove (Figure 7.104),

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.66  Vascular pannus on the dorsal surface of the medial meniscus in a dog with a cranial cruciate ligament rupture. This is the stifle of the dog with pannus in a cartilage indentation on the femoral condyle shown in Figure 7.63, and the pannus lesion is seen in the upper right of the picture. Damaged meniscus is seen extending across the center of the image immediately below the articular surface with the pannus lesion on the meniscus in the lower right. Proximal or dorsal is up on the image, and the telescope is looking caudomedially from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.68  Mild vascular pannus on the long digital extensor tendon in the stifle of a dog with a cranial cruciate ligament injury. The telescope is looking laterally from a craniomedial portal with proximal or dorsal up and lateral to the right. The craniolateral portion of the lateral femoral condyle fills the left side of the picture with the long digital extensor tendon seen as a vertical band in the center, and reactive joint capsule along the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

as multiple blisters or swelling on the caudal surface of the patella (Figure  7.105) and in the trochlear groove (Figure 7.106), and as swelling of the tibial plateau cartilage (Figure 7.107). Grade II chondromalacia of articular cartilage occurs on the femoral condyles as focal (Figure  7.108) or diffuse (Figure  7.109) fibrillation, fibrillation on the tibial plateau (Figure  7.110), in the

Figure 7.67  Vascular pannus on the articular cartilage surface of an osteophyte on the abaxial surface of the medial femoral trochlear ridge. The telescope is looking proximally from a craniomedial portal with cranial up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.69  Marked vascular pannus on the long digital extensor tendon in the stifle of a dog with a cranial cruciate ligament injury. The long digital extensor tendon fills the center of the image with a small portion of femoral condyle on the left and joint capsule on the right. Orientation is the same as the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

trochlear groove as fibrillation (Figure 7.111) or superficial mild fissures with fibrillation (Figure 7.112), and on the caudal surface of the patella as fine fibrillation (Figure  7.113) or erosions (Figure  7.114). More severe chondromalacia, Grade III, is also seen in all areas of the stifle joint with lesions occurring in the trochlear groove as fibrillation (Figure  7.115), fissures (Figure 7.116), and erosions (Figure 7.117); fibrillation (Figure 7.118) and erosions (Figure 7.119) on the caudal surface of the patella; femoral condyle lesions with erosions (Figure  7.120), coarse fibrillation (Figure  7.121), or fine fibrillation (Figures 7.122 and 7.123); and on the tibial plateau (Figure 7.124). Grade IV chondromalacia

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Figure 7.70  Vascular pannus on the surface of an apparently intact cranial cruciate ligament. There was a very early partial rupture that was not visible in this image but was visible on the caudomedial corner of the ligament. Proximal or dorsal is up on the image and lateral is to the left. The caudal cruciate ligament is visible in the upper right side of the picture and fat pad is in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.72  Vascular pannus on the caudal cruciate ligament in a dog with a cranial cruciate ligament rupture, vertical splitting of the caudal cruciate ligament, and visible transverse striations indicating that the ligament is loose. Dorsal or proximal is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.74  Osteophytes in the suprapatellar pouch proximal to the cartilage of the trochlear groove appearing as a relatively flat smooth extension of cartilage with Grade III chondromalacia. The telescope is looking proximally, and cranial is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.71  Vascular pannus on a loose completely ruptured cranial cruciate ligament. The cruciate ligament almost completely fills the image with a small portion of femoral condyle visible in the upper left. Proximal or dorsal is up, and medial is to the right with the telescope looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.73  The vascular pannus lesion seen in Figure 7.62 when increased intra-articular pressure has compressed the blood vessels making the lesion less distinct. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.75  Multiple rounded osteophytes are seen in this patient with shallow separations in the suprapatellar area giving a “cobble stone” appearance extending proximal to the trochlear groove cartilage. The image is obliqued with cranial to the upper left, and the telescope is looking proximally into the suprapatellar pouch. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.76  Multiple rounded osteophytes with deep separations are seen in the suprapatellar area extending proximal to the trochlear groove cartilage. This image is obliqued with cranial to the upper left and the telescope looking proximally. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.78  A prominent raised transverse osteophyte ridge is in the suprapatellar joint space proximal to the trochlear groove cartilage. Cranial is up, and the telescope is looking proximally. A small area of the caudal surface of the patella is seen at the upper left, and the proximal end of the trochlear articular cartilage is seen across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.80  A sharp elevated ridge of osteophyte is extending medially and proximally from the proximal trochlear groove cartilage. Cranial is up on the image with medial to the left, and the telescope is looking proximally. The suprapatellar pouch with villus synovial reaction fills the upper portion of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.77  A rim of osteophytes in the suprapatellar joint space is visible proximal to the trochlear groove cartilage surrounding a central recessed area without osteophyte formation. The central recess in this image contains reactive synovium with petechia. Cranial is slightly to the right of up on the image, and the telescope is looking proximally. Source:  Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.79  A flat osteophyte proliferation is present extending medially from the proximal end of the trochlear groove cartilage in the suprapatellar pouch. The telescope is looking proximally, cranial is up, and medial is to the left. Villus covered joint capsule of the suprapatellar pouch is seen in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.81  An elevated osteophyte is appearing as a proximal extension of the lateral trochlear ridge projecting into the suprapatellar joint space. The image is slightly obliqued with cranial to the left of up and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.82  An isolated osteophyte is present in the suprapatellar pouch proximal and medial to the medial trochlear ridge cartilage. The telescope is looking proximally from a craniomedial portal with cranial up and medial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.84  A large prominent osteophyte ridge at the articular cartilage margin on the medial abaxial aspect of the femoral condyle seen with the telescope in the medial joint space from the craniomedial portal. Cranial is up and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.86  A large irregular osteophyte ridge at the articular cartilage margin on the medial abaxial surface of the femoral condyle seen with the telescope in the cranial joint space from the craniomedial portal. Cranial is up, and medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.83  A small smooth ridge of osteophytes at the articular cartilage margin on the medial abaxial aspect of the femoral trochlea is seen with the telescope in the medial joint space from the craniomedial portal. Cranial is up and medial is to the right. The medial joint capsule is covered with villus ghosts. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.85  A large smooth osteophyte ridge at the articular cartilage margin on the medial abaxial aspect of the femoral condyle seen with the telescope in the medial joint space from the craniomedial telescope portal. Cranial is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.87  A flattened osteophyte ridge at the articular cartilage margin on the medial abaxial surface of the femoral condyle seen with the telescope in the cranial joint space from the craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.88  A small osteophyte ridge at the articular cartilage margin on the lateral abaxial surface of the femoral condyle seen with the telescope in the craniomedial portal and positioned across the trochlea. Cranial is up, and lateral is to the right. The joint capsule is covered with moderate villus synovial reaction. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.90  A large irregular osteophyte ridge at the articular cartilage margin on the lateral abaxial surface of the femoral condyle seen from the cranial joint space with the telescope in the craniomedial portal. Cranial is up, and lateral is to the right. An egress cannula is visible in the lateral joint space. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.92  A flattened osteophyte ridge at the articular cartilage margin on the lateral abaxial surface of the femoral condyle seen from the cranial joint space with the telescope in the craniomedial portal. The image is obliqued, and cranial is to the upper left with lateral to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.89  A large smooth osteophyte ridge at the articular cartilage margin on the lateral abaxial surface of the femoral condyle seen from the cranial joint space with the telescope in the craniomedial portal. The telescope is positioned across the front of the trochlea from a craniomedial portal. The lateral ridge of the trochlea is visible on the left side of the image, the osteophyte is running vertically in the center, and lateral joint capsule is on the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.91  A large irregular cluster of osteophytes at the articular margin on the lateral abaxial surface of the femoral condyle seen from the cranial joint space with the telescope in the craniomedial portal. Cranial is up, and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.93  An osteophyte within the articular cartilage on the medial abaxial surface is seen at the top of the medial trochlear ridge. The osteophyte is the small raised area on the left side of the medial trochlear ridge on the far left of the image. Cranial is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.94  Osteophytes within the articular cartilage are seen on the top and abaxial surface of the proximal end of the lateral trochlear ridge. Cranial is up and lateral is to the right. The telescope is looking proximally from a cranio­ medial portal across the cranial surface of the trochlea. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.96  An osteophyte seen at the distal end of the patella. Proximal is to the upper left, and cranial is to the upper right. The trochlear groove fills the lower half of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.98  An osteophyte seen on the lateral margin of the patella. The telescope is positioned across the trochlea from a craniomedial portal. The articular surface of the patella with Grade III chondromalacia is in the upper left of the image with the osteophyte coursing obliquely across the center. Cranial is up, and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.95  An osteophyte at the proximal end of the patella. The telescope is positioned in the trochlear groove looking proximally from a craniomedial portal and cranial is up. The caudal articular surface of the patella fills the upper portion of the image with the osteophyte at the proximal end and villus ghosts of the suprapatellar pouch joint capsule are seen in the bottom background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.97  An osteophyte is on the medial margin of the patella. The telescope is looking proximally in the medial joint space from a craniomedial portal. The abaxial surface of the medial trochlear ridge is visible in the lower right with the medial margin of the patella in the upper right. The osteophyte is seen as a projection on the medial surface of the patella in the center of the image. Cranial is up, and medial is to the left. An egress cannula is seen on the far right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.99  Large osteophytes are seen on the medial margin and at the proximal end of the patella. The telescope is in the trochlear groove and is elevating the patella away from the trochlear cartilage. Cranial is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.100  An osteophyte in the area of the intercondyloid eminence of the tibia filling the center of the image. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.102  Soft tissue lesions arranged in a row on the abaxial surface of the femoral condyle in the area where osteophytes are commonly seen. These lesions were very pliable with their surface moving with fluid flow. Are these lesions the origin of osteophytes or are they an unrelated synovial reaction? Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.104  A single Grade I chondromalacia cartilage blister is seen in the trochlear groove of a dog with a cranial cruciate ligament injury. The trochlear groove cartilage fills the lower right of the image with the caudal surface of the patella in the upper left. The telescope is positioned in the trochlear groove from a craniomedial portal looking proximally with cranial up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.101  An osteophyte in the intercondyloid fossa of the femur seen lateral and caudal to the caudal cruciate ligament. Lateral is to the left, and proximal is up with the telescope looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.103  A single cartilage blister is seen on the medial femoral condyle representing Grade I chondromalacia in the stifle of a dog with a cranial cruciate ligament injury. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up and medial to the right. The condyle fills the top of the image with the cranial portion of the medial meniscus in the lower right and the cranially folded caudal pole of the medial meniscus visible extending horizontally across the center of the image to the left edge. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.105  Multiple Grade I chondromalacia cartilage blisters or swellings are seen in the proximal end of the trochlear groove in the stifle of a dog with a cranial cruciate ligament injury. The telescope is positioned in the trochlear groove from a craniomedial portal with cranial up. The patella fills the top of the image with the trochlear groove across the bottom and the suprapatellar pouch in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.106  Multiple Grade I chondromalacia cartilage blisters or swellings are seen on the proximal end of the caudal articular surface of the patella in the same joint as in the previous image. Orientation is the same as in the previous image with the telescope positioned slightly more proximal and the angle of view rotated to look cranially. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.108  Mild focal fibrillation of the femoral condyle articular cartilage demonstrating Grade II chondromalacia in the stifle of a dog with a cranial cruciate ligament injury. The telescope is looking caudolaterally from a craniomedial portal with proximal or dorsal up and cranial to the right. The lateral femoral condyle is filling the top of the image with the tibial plateau in the lower left, the axial margin of the lateral meniscus to the right-center, and the backside of a shaver blade in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.107  Grade I chondromalacia swelling of the tibial plateau cartilage in a dog with a cranial cruciate ligament injury and Grade III chondromalacia of the femoral condyle seen as frayed cartilage in the upper right. The telescope is looking caudally from a craniomedial portal and proximal or dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.109  Diffuse Grade II fibrillation of the articular cartilage on the femoral condyle of a dog with cranial cruciate ligament injury. The femoral condyle fills the top of the image with the tibial plateau across the bottom. Proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc. Figure 7.110  Diffuse fine fibrillation of the tibial plateau articular cartilage, Grade II chondromalacia, in the stifle of a dog with cranial cruciate ligament rupture. Proximal or dorsal is up with the femoral condyle filling the upper half of the figure and the tibial plateau across the bottom. A portion of the frayed axial margin of the medial meniscus is visible in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.111  Fine fibrillation of the trochlear groove representing Grade II chondromalacia in the stifle of a dog with cranial cruciate ligament disease. The telescope is positioned looking proximally in the trochlear groove with cranial up. The patella fills the top of the image with the trochlear groove articular surface filling the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.113  Fine fibrillation of the articular cartilage on the caudal aspect of the patella representing Grade II chondromalacia. The image is slightly obliqued with cranial to the upper left. The telescope is positioned in the trochlear groove and is looking proximally. The patella is in the upper left, and the trochlear articular surface is in the lower right. Mild irregular swelling of the trochlear groove cartilage represents Grade I chondromalacia. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.112  Grade II chondromalacia of the trochlear groove articular cartilage seen in the stifle of a dog with a ruptured cranial cruciate ligament. The cartilage in this image shows both fissures in the foreground and fibrillation in the background. The telescope is positioned in the trochlear groove looking proximally from a craniomedial portal and cranial is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

has most commonly been seen on the femoral condyle as a focal area of depressed roughened cartilage with full-thickness fissures (Figure  7.125) or as focal fullthickness cartilage loss with either fibrillated or fractured cartilage debris within the defect (Figure 7.126). These lesions are located and have the appearance suspiciously similar to chronic untreated OCD. Fullthickness cartilage loss with exposed eburnated bone,

Figure 7.114  A small area of superficial erosion on the caudal surface of the patella, Grade II chondromalacia, in the stifle of a dog with cranial cruciate ligament disease. The image is obliqued slightly to the left so that cranial is to the upper left. The caudal surface of the patella fills the upper left of the image with the chondromalacia lesion in the lower left of the visible cartilage surface. The trochlear groove is to the lower right, and the suprapatellar pouch is to the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.115  Grade III chondromalacia seen at the proximal end of the trochlear groove demonstrated as coarse cartilage fibrillation in a dog with chronic cranial cruciate ligament rupture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.117  A deep cartilage erosion. Grade III chondromalacia, in the articular cartilage of the trochlear groove in a dog with cranial cruciate ligament disease. The surrounding trochlear groove cartilage is slightly roughened representing Grade I chondromalacia. The telescope is positioned looking proximally in the trochlear groove and is slightly obliqued with cranial to the upper left. The caudal surface of the patella is filling the upper left of the image, and the trochlear groove is to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.116  Chondromalacia, Grade III, of the trochlear groove seen in the stifle of a dog with a ruptured cranial cruciate ligament with generalized cartilage roughening and a fissure in the lower right extending to but not exposing bone. The telescope is positioned in the trochlear groove looking proximally from a craniomedial portal and cranial is up. Marked villus synovial reaction of the suprapatellar pouch is seen in the upper portion of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Grade V chondromalacia, is not commonly seen in the stifle joint but can occur on the femoral condyle and tibial plateau with chronic untreated cranial cruciate ligament rupture (Figure 7.127). Examination of structures in the cranial joint space and intercondylar area is greatly facilitated by partial fat pad resection and partial synovectomy of the villus synovial reaction. Evaluation of the cruciate ligament and

Figure 7.118  Grade III chondromalacia seen as fibrillation of articular cartilage on the caudal surface of the patella in a dog with a partially ruptured cranial cruciate ligament. The telescope is positioned in the trochlear groove looking proximally with cranial to the upper right. The caudal surface of the patella fills the upper right of the image, and trochlea is to the lower left. Irregular swelling or blisters of the trochlear cartilage represents Grade I chondromalacia. A small amount of blood has settled on the trochlear articular surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.119  Erosion of the articular cartilage on the caudal surface of the patella and in the trochlear groove, Grade III chondromalacia, seen in a dog with cranial cruciate ligament disease. The telescope is positioned in the trochlear groove and is looking proximally from a craniomedial portal. Cranial is up. The caudal surface of the patella is in the upper portion of the image with the trochlear groove at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.121  Coarse fibrillation of articular cartilage on the femoral condyle representing a Grade III chondromalacia lesion. The telescope is looking caudally from a craniomedial portal with the image obliqued so that proximal is to the upper right. The tibial plateau with Grade I chondromalacia is present to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.120  Grade III articular cartilage erosion on the femoral condyle in a dog with cranial cruciate ligament disease. The telescope is looking caudally from a craniomedial portal with proximal up on the image. The femoral condyle fills top of the picture with the tibial plateau in the lower left and ruptured strands of the cranial cruciate in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.122  Grade III chondromalacia seen as focal area of fine fibrillation of the articular cartilage on the femoral condyle of a dog with a cranial cruciate ligament rupture. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up. The femoral condyle is filling the top of the image with the tibial plateau across the bottom. Chondromalacia is also present in the tibial plateau cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

menisci can be attempted prior to or without tissue resection and this is possible in normal joints, joints with true acute cruciate ligament ruptures, or with other pathology that causes only mild villus synovial reaction. Typical villus synovial reaction seen in cruciate compromised stifles (Figure  7.41) makes effective

visualization of the cruciate ligaments and menisci very difficult or impossible without partial synovectomy. Fat pad resection also facilitates joint examination. Complete cruciate ligament ruptures or major partial tears may be visible without cranial compartment debridement, but the chance of missing a minor partial

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Figure 7.123  Using a 2.0 mm graduated manipulation probe to determine the depth of the chondromalacia lesion seen in the previous image. Orientation is the same as in the previous image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.124  Grade III chondromalacia of the articular cartilage on the tibial plateau of the case seen in Figures 7.122 AND 7.123. The 2.0 mm graduated manipulation probe is used to determine the depth of cartilage damage to confirm Grade III chondromalacia. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

tear of the cranial cruciate ligament is greatly increased when debridement is not performed. If the only purpose of arthroscopy is to confirm a diagnosis of cruciate ligament injury that is going to be followed by an open arthrotomy, and if free strands of ruptured ligament are seen, then the arthroscopic portion of the procedure can be completed without removing the fat pad or cranial compartment villus synovial reaction. For any operative arthroscopic procedures, partial fat pad removal and partial cranial compartment synovectomy are absolutely essential.

Figure 7.125  A Grade IV chondromalacia lesion on the medial condyle of the femur at the area where OCD is commonly found in a dog with a ruptured cranial cruciate ligament. Is this an old untreated OCD lesion or is this chondromalacia secondary to the cruciate ligament injury? The telescope is looking caudally from a craniomedial portal with proximal or dorsal up. The femoral condyle fills the upper portion of the image with the tibial plateau across the bottom and the medial meniscus is seen in the background with fraying of its axial margin. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.126  Fractured cartilage in a Grade IV chondromalacia lesion on the medial condyle where OCD is commonly located in a dog with a complete cranial cruciate ligament rupture. Again, the question is this an old untreated OCD lesion or is this secondary to the cruciate ligament injury? The telescope is looking caudally from a craniomedial portal with proximal or dorsal up. The femoral condyle fills the upper right with the tibial plateau across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

When the cranial cruciate ligament ruptures, the torn strands of ligament most commonly separate into fine fibers like the end of a frayed parted rope (Figures 7.41, 7.128, and  7.129). Recently ruptured ligament fibers

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

typically have sharp pointed tips and well-defined striations within the individual loose strands (Figures 7.41 and 7.129). Additional common appearances of cranial cruciate ligament ruptures include larger coarse bands

Figure 7.127  Grade V chondromalacia on the femoral condyle and tibial plateau seen in the stifle of a dog with a chronic complete cranial cruciate ligament rupture and that previously had the stifle debrided without a stabilization procedure. The eburnated bone of the femoral condyle is visible across the top of the picture with the exposed bone of the tibial plateau in the center and articular cartilage across the bottom. The medial meniscus is visible in the right center on top of fibrillated tibial plateau articular cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.128  A completely ruptured cranial cruciate ligament with a typical fine multistrand appearance like the ends of a frayed parted rope. The telescope is looking caudally at the intercondyloid fossa from a craniomedial portal with proximal or dorsal up on the image. The frayed ligament end almost fills the entire frame with a small portion of the medial femoral condyle indistinctly visible on the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

of ligament fibers (Figure  7.130), and large intact segments of ligament (Figure  7.131). Less common findings are loose intact portions of avulsed cranial cruciate ligament with (Figure 7.132) or without (Figure 7.133) visible cross striations, avulsion or rupture of the origin of the ligament (Figure  7.134), avulsion or rupture of

Figure 7.129  An acute completely ruptured cranial cruciate ligament with fine ligament fibers. The strands have sharp pointed tips and well-defined cross striations indicating a recent injury. The telescope is directed caudally into the intercondyloid fossa from a craniomedial portal. Proximal or dorsal is up on the image. The ruptured cranial cruciate ligament fibers completely fill the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.130  Coarse bundles of ligament fibers, combined with fine fibers, from a completely ruptured cranial cruciate ligament. The variety of fiber bundle size is frequently seen. The figure is completely filled with cruciate ligament, and no other structures are in the image, seen with the telescope looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.131  A large segment of intact ligament tissue seen as part of a completely ruptured cranial cruciate ligament. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal with proximal or dorsal up and medial to the left. The ruptured cranial cruciate ligament is on the right, and the intact caudal cruciate ligament is filling over half of the left side of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.132  An intact portion of an avulsed cranial cruciate ligament is seen crossing the bottom of this figure. Visible cross striations indicate that the ligament is loose and has lost its normal tension. Any time that cross striations are seen, as in this picture, it indicates that the ligament is loose. Even if no broken fibers are seen this finding is enough to confirm a cruciate ligament injury. The pannus on the ligament also indicates injury. The telescope is looking caudally from a craniomedial portal into the intercondyloid fossa with proximal up on the image and medial to the right. The distal end of the ligament was avulsed from the tibial plateau and was displaced laterally. The craniolateral surface of the medial femoral condyle is visible in the top half of the picture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.133  An intact portion of an avulsed cranial cruciate ligament is seen without visible cross striations. The ligament is bent indicating that it is no longer tightly stretched and there is also a small area of ruptured fibers on the ligaments lower surface. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal with proximal up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.134  Acute avulsion or complete rupture at the origin of a cranial cruciate ligament seen as fine fibers. Up is proximal or dorsal with medial to the right. The frayed ligament is in the center with caudal cruciate ligament to the right and axial surface of the lateral femoral condyle on the left. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the insertion of the ligament (Figure 7.135), split ligaments without visible rupture or avulsion (Figure 7.136), and hematomas within ruptured ligaments (Figure 7.137). As cranial cruciate ligament ruptures become chronic the ends of small strands lose their sharp margins and

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

striations to become blunted (Figure 7.138). The ends of large ligament segments become rounded and smooth with consolidation of individual strands into a single blunt mass (Figure 7.139). With progressive chronicity, the ligament ends undergo remodeling to become nodules of fibrous tissue (Figure 7.140) and are eventually completely reabsorbed. The most common appearance of the ruptured strands of injured cranial cruciate ligaments is a combination of acute and chronic changes of ruptured fibers (Figure  7.141) lending support to the thought that there is a slow progression of injury with repeated episodes of partial tearing over a period of time to eventual complete rupture. Incomplete ruptures or tears have a variable quantity of intact fibers and show the same pattern of ruptured fiber appearance with acute, blunting, loss of striations, and resorption with progressive chronicity as seen with complete ruptures. The combination of changes from acute to chronic progression also occurs with partial tears as shown for complete ruptures (Figure 7.141). Early partial tears with a minimal number of ruptured ligament fibers are most typically first seen as ruptured ligament strands coming from the caudal aspect of the distal cranial cruciate ligament medially (Figure  7.142), laterally (Figure  7.143), both medially and laterally, or occasionally in the central portion of the ligament (Figure 7.144). Early origin (Figure 7.145) and insertion (Figure 7.146) injuries also occur. A probe is used to palpate and manipulate the caudal area of the insertion of the cranial cruciate ligament if it appears normal on initial examination (Figure 7.147). Minimal ligament injuries can also be detected, even in the absence of visible ruptured fibers, by the presence of cross striations in the intact ligament indicating that normal tension has been taken off the ligament (Figure 7.148). The classically described injuries to the medial meniscus are easily seen with arthroscopy including small bucket handle tears (Figure 7.149), typical larger bucket handle tears (Figure 7.150), and broken bucket handle or parrot beak tears (Figure 7.151). Bucket handle tears are not always readily apparent with the meniscus, including the bucket handle portion, can be seen in situ as normal-appearing tissue (Figure 7.152). Manipulation of the joint or exploration with a probe will expose the tear and displace the bucket handle into the cranial compartment of the joint (Figure  7.153) (Video 7.3). Cranial displacement of bucket handle fragments commonly occurs with easily seen attachments (Figure  7.154) or the folded segment can be large enough to obscure its attachments (Figure 7.153). The bucket handle can be relatively normal-appearing

Figure 7.135  Avulsion or complete rupture at the insertion of a cranial cruciate ligament with the residual fibers protruding from under the cranial pole of the medial meniscus. Dorsal or proximal is up on the image with medial to the left. The medial femoral condyle fills the upper half of the picture with a small portion of the medial meniscus in the far lower left with frayed ligament fibers protruding from under the meniscus. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.136  A split cranial cruciate ligament with two bands of loose visibly intact ligament tissue in the stifle of the dog in the previous image. The two bands of ligament completely fill the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figures 7.153 and 7.154) or can be in severely damaged condition (Figure 7.155). In some cases, the entire caudal pole of the meniscus is trapped cranial to the femoral condyle (Figure 7.156) and the caudal meniscotibial ligament can be displaced cranially with the caudal pole of the medial meniscus (Figure 7.157). There can also be crushing or maceration of the entire caudal pole of the meniscus (Figure 7.158).

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Figure 7.137  A hematoma seen in the intact portion of an acute partial avulsion or rupture of the cranial cruciate ligament. Ruptured fibers are visible in the lower left with the injured but intact portion of the ligament obliquely crossing the lower right and the medial non-articular surface of the lateral femoral condyle in the upper left. Proximal is up, and the telescope is looking caudally from a craniomedial portal. Medial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.139  The end of a large ligament segment that has remodeled into a smooth blunt structure. Villus synovial reaction is visible in the lower right of the image with caudal cruciate ligament in the upper left and the axial surface of the lateral femoral condyle in the upper right. The telescope is looking caudally from a craniomedial portal with proximal at the top and medial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Additional pathology that cannot be easily visualized with open surgery has also been defined with arthroscopy. The most significant of these findings is damage to the lateral meniscus occurs more frequently than medial meniscal injuries (Ralphs and Whitney 2002). The most

Figure 7.138  A close-up view of ruptured strands of a cranial cruciate with blunted ends and loss of cross striations typical of a chronic injury. Chronicity in this stifle is also indicated by pannus on the surrounding structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.140  Chronic cranial cruciate ligament remnants that have undergone extensive remodeling and resorption into nodules of fibrous tissue. Proximal is at the top of the image with medial to the left. The remodeled ligament end is in the center of the picture with caudal cruciate ligament to the left and the axial surface of the lateral femoral condyle on the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

common lateral meniscal injury is mild fraying of the cranial portion of the axial margin (Figure 7.159). Axial margin fraying is also seen in the central area (Figure 7.160) and caudal portion (Figure 7.161) of the lateral meniscus. More severe axial margin injuries of the lateral meniscus are much less common but do occur (Figure 7.162). Bucket handle tears in the lateral meniscus are also uncommon and can be small (Figure 7.163) to large (Figure 7.164).

Figure 7.141  A close-up view of a cranial cruciate ligament with recently ruptured strands having sharp points and cross striations along with other ruptured strands showing chronic changes of blunting in some and blunting with loss of cross striations in one in the bottom center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.143  An early partial cranial cruciate ligament rupture demonstrated as a small cluster of fine ligament fibers protruding from the caudolateral aspect of the distal ligament. Normal-appearing ligament fills the image with the ruptured fibers at the top center. The telescope is looking medially from a craniomedial portal with proximal or dorsal up and medial to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.145  An early partial cranial cruciate ligament injury at the proximal end seen as an avulsion or rupture of fibers at its origin. The caudal cruciate ligament is on the far left with the axial surface of the lateral femoral condyle on the far right of the picture. Proximal or dorsal is up with medial to the left, and the telescope is looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.142  An early partial cranial cruciate ligament tear with a small ruptured ligament strand protruding from the caudomedial aspect of the distal ligament. The frayed tip and visible striations indicate that this is an acute injury. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.144  An early partial cranial cruciate ligament injury with a small group of ruptured ligament fibers seen at the center of the ligament on the medial margin. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal with proximal up and medial to the right. The cranial cruciate ligament is in the lower left side of the image with the caudal cruciate ligament filling the right side. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.146  An early partial cranial ligament injury on the craniolateral aspect of its insertion as an avulsion or rupture of fibers at the insertion. The intact fibers of the cranial cruciate ligament are seen in the lower left with the fibers going under the axial margin of the lateral meniscus at the very bottom and with the ruptured fibers filling the center of the image. The lateral femoral condyle is visible in the upper background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.147  Additional ruptured cranial cruciate ligament fibers found in the joint seen in Figure 7.143 after manipulation of the joint and probing of the lateral margin of the ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.149  A small bucket handle tear seen in the caudal pole of the medial meniscus of a dog with a cranial cruciate ligament rupture. The tip of a 1 mm diameter hook probe is seen in the far right of the image. The telescope is positioned in the intercondyloid fossa looking caudomedially from a craniomedial portal with dorsal or proximal up and medial to the left. The medial femoral condyle is filling the upper right of the image with the axial margin of the medial meniscus folded in the bottom center, and a small area of tibial plateau at the very bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Management of cranial cruciate ligament injuries using arthroscopy has been a natural evolution of diagnostic procedures. Arthroscopic debridement of minor partial cranial cruciate ligament injuries, remnant resection for major partial or incomplete tears, resection of the ligament ends with complete ruptures (Video 7.4), and debriding meniscal injuries has become a standard surgical approach obviating need for open arthrotomy in

Figure 7.148  Visible cross striations in a loose cranial cruciate ligament with no visible ruptured fibers. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.150  A large bucket handle tear of the caudal pole of the medial meniscus that is more typical in size. The instrument on the left side of the image is depressing and retracting the free bucket handle segment to expose the tear. The free bucket handle segment fills the lower portion of the image and extends beyond the lower edge so that the axial margin is not visible. The bucket handle portion of the meniscus has been damaged by crushing. The peripheral intact portion of the medial meniscus is seen in the background extending horizontally behind the meniscal tear. A small portion of medial femoral condyle is in the far upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

management of cruciate compromised stifles. Partial removal of the cranial compartment fat pad and partial cranial compartment synovectomy is necessary to create an adequate visual field. Radiofrequency with the VAPR is used initially to remove fat pad and villus synovial reaction tissue in the cranial joint compartment until visibility is achieved (Figure 7.165). The power shaver is also used as needed to remove avascular cranial

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.151  A broken bucket handle or parrot beak tear of the caudal pole of the medial meniscus. This occurs when one end of the bucket handle breaks away from the meniscus creating a free end. The telescope is looking caudally into the intercondyloid fossa from a craniomedial portal with proximal or dorsal up and medial to the right. The medial femoral condyle fills the upper half of the image with the free end of the bucket handle just beyond the left edge and the attached craniomedial end just beyond the right edge. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.153  The bucket handle in the patient from the previous figure that was in a normal position caudal to the femoral condyle in that image and has now folded cranially to be trapped by the femoral condyle. The folded segment is large enough to obscure the attachments of the bucket handle. The medial condyle of the femur fills the upper portion of the picture with the folded caudal pole bucket handle filling the center, and the dorsal surface of the cranial pole of the medial meniscus is seen extending across the bottom and up the left side. Dorsal or proximal is up, and medial is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.152  The medial meniscus seen in this image has a large bucket handle tear that cannot be seen with the visible medial meniscus appearing normal. The only indication of pathology is the vascular synovial villus to the lower right. The telescope is looking caudomedially from a craniomedial portal with the medial femoral condyle in the upper left and the tibial plateau in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.154  The medial lateral attachment of a bucket handle tear of the caudal pole of the medial meniscus that is displaced cranially and trapped cranial to the femoral condyle. (Anderson, Toss[L] 25 June 2003 PNP00117 MDISK34 117). Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

compartment fat (Figure 7.166) alternating with radiofrequency (Figure 7.167) when indicated to remove vascular tissue until an adequate visual field is established. After creation of an adequate visual space, the joint is examined to assess the extent of cranial cruciate ligament injury, to define meniscal injuries, and to determine the extent and grade of chondromalacia. With

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Figure 7.155  The axial margin of the medial meniscus in this image is severely damaged due to crushing from instability that allows the femoral condyle to slide back and forth over the meniscus. A hook probe is being used to manipulate the axial margin for assessing the extent of damage and to define the bucket handle. The telescope is looking caudomedially from a craniomedial portal with the medial femoral condyle in the upper right, the bucket handle is seen extending horizontally across the center, and the tibial plateau is visible at the bottom of the image below the hook probe. Dorsal or proximal is up, and medial is to the right. The probe is inserted through a craniolateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.157  When the entire caudal pole of the medial meniscus is displaced cranially, as seen in the previous figure, the caudal meniscotibial ligament is also displaced cranially. The displaced meniscotibial ligament is visible as a horizontal band crossing the center of the image with the femoral condyle in the upper left and the tibial plateau visible at the bottom. Medial is to the left, and proximal or dorsal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.156  The entire caudal pole of the medial meniscus has been displaced cranially in this patient and trapped in front of the femoral condyle. Peripheral tissue visible medial to the meniscus and femoral condyle, at the far right, has been modified with the VAPR to remove villus synovial tissue obscuring the visual field. Dorsal or proximal is up, and medial is to the right. The craniomedial aspect of the medial condyle is seen in the upper left, and the cranially folded caudal pole of the medial meniscus is seen in the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.158  Crushing or maceration of the entire caudal pole of the medial meniscus occurs in some patients. The frayed strands of tissue in the center of the image represent the entire shredded caudal pole of the medial meniscus. The medial femoral condyle fills the top of the image, and the dorsal surface of the cranial pole of the medial meniscus is seen across the bottom. Dorsal or proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.159  The most common injury to the lateral meniscus is mild axial margin fraying involving the cranial pole. The frayed area of the axial margin is in the center of the image with the intact peripheral cranial pole to the right and below the frayed tissue. The small tissue projection in the upper right portion of the image with cross striations is a strand of ruptured cranial cruciate ligament. An area of lateral femoral condyle is seen in the upper right, and tibial plateau articular surface is visible to the left of the frayed tissue. Dorsal or proximal is up, and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.160  Mild axial margin fraying of the central portion of the lateral meniscus. The image is slightly obliqued with proximal to the upper left and lateral to the lower left. The lateral femoral condyle fills the upper three quarters of the picture with the lateral meniscus at the bottom and the tibial plateau to the far right. The axial margin of the lateral meniscus is seen coursing from the lower right foreground to the lower center background with the frayed segment visible in the center background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.161  Axial margin fraying of the caudal portion of the lateral meniscus. The image is obliqued with the telescope looking caudolaterally from a craniomedial portal with proximal to the upper right and lateral to the upper left. The lateral femoral condyle fills the upper right with the tibial plateau to the lower left, the lateral meniscus is seen coursing obliquely from the upper left to the lower right and the frayed area is the right lower half of the visible meniscus. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.162  A major radial tearing injury to the cranial pole axial margin of the lateral meniscus in a dog with a ruptured cranial cruciate ligament. The lateral femoral condyle fills the top of the picture with tibial plateau visible across the bottom, and the lateral meniscus is on the far right with the damaged tissue extending to the left across the center. Proximal is up, and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.163  A small bucket handle tear is seen in the lateral meniscus as a band of damaged tissue extending from the center to the far right with intact meniscus extending obliquely to the upper left. The lateral femoral condyle fills the upper right and the tibial plateau the lower left. An area of indistinct pannus is visible in a depression on the surface of the lateral femoral condyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.164  A large bucket handle tear of the lateral meniscus with the bucket handle folded and trapped craniolateral to the femoral condyle. The telescope is looking laterally from a craniomedial portal, and proximal is up with craniolateral to the right. The lateral femoral condyle fills the left half of the image with the folded bucket handle to the lower right and reactive joint capsule in the background of the upper right. The tip of a hook probe is visible in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

complete cranial cruciate ligament ruptures, the frayed ends of the ligament are removed using the shaver (Figure 7.168). Complete ligament removal is achieved in most cases (Figure  7.169). Incomplete removal with the shaver (Figure 7.170) is followed with radiofrequency to smooth the remnants of the ligament ends

Figure 7.165  To establish a visual field, radiofrequency is used initially to remove fat and villus synovial tissue. This image shows a small side effect VAPR electrode. The center silver oval is the active electrode, and the white material surrounding the electrode is insulating ceramic. The ground for this bipolar system is around the shaft just beyond the right margin of the picture. The telescope is looking caudally into the intercondyloid fossa, and hyperemic reactive synovium is visible in the foreground filling the bottom half of the image with frayed cruciate ligament to the upper left of the VAPR device. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

(Figure  7.171). Debridement of chronic rupture ligament end remnants is done with radiofrequency using either the small-sized VAPR handpieces (Figure  7.172) in most patients, with the larger-sized handpieces needed in the largest patients (Figure 7.173). Minor partial tears are typically managed with radiofrequency, and complete resections are performed using a combination of radiofrequency and a power shaver. Hand instruments have been used for ligament removal but are typically inadequate making the procedure too time-consuming. Partial and total meniscectomies are performed with arthroscopy using hand instruments, the power shaver, radiofrequency, or commonly a combination of these instruments. Bucket handle tears are removed with duckbill meniscus cutters (Figure  7.174) that allow placement between the articular surfaces onto the damaged meniscus at the ends of the bucket handle (Figures  7.174 and  7.175) to cut the end of the separated meniscal tissue (Figure 7.176). Once cut the freed end of the bucket handle is grasped with the duckbill cutter (Figure 7.177) or with grasping forceps and traction is applied to displace the bucket handle segment into the cranial joint space. The other end of the bucket handle that is still attached is cut with the duckbill meniscus cutters or in some cases simply

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.166  A power shaver is also used when indicated for removal of avascular tissue to establish a visual field. A 3.5 mm diameter shaver blade is visible in the intercondyloid fossa entering from a craniolateral portal. Partially resected fat pad tissue fills the bottom of the image. Proximal or dorsal is up, and lateral is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.168  Removing a ruptured cranial cruciate ligament with the power shaver using a 4.0 mm aggressive cutting blade. The outer cannula of the shaver blade fills the top of the figure with frayed strands of ruptured cranial cruciate filling the lower half. Suction is applied through the shaver to pull tissue into the blade opening so that the rotating inner blade cuts the tissue and sucks it out through the shaver. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.167  The radiofrequency device is used in combination with the shaver for removal of vascular tissue and to control bleeding caused by invasion of the shaver into vascular tissue. This image shows a small wedge effect VAPR electrode inserted through a craniolateral portal. The black flat structure at the left end of the instrument at a 45° angle is the active electrode, the white ceramic is insulation, and the silver to the right is the ground electrode. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.169  Remnants of the origin of the cranial cruciate ligament seen on the medial aspect of the lateral femoral condyle after complete removal with the power shaver. The telescope is looking caudally from a craniomedial portal with proximal up and lateral to the right. The caudal cruciate ligament is on the left, the remnant of the origin of the cranial cruciate ligament is in the center, axial surface of the lateral femoral condyle is on the right, and a small portion of tibial plateau is visible at the bottom center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

pulled free of its attachment and removed. Rongeurs are also used for removal of freed bucket handle tissue, but the shape of the instrument interferes with access between cartilage surfaces (Figure 7.178) making the procedure more difficult. The power shaver is also used to remove bucket handle tears that have had

one end freed (Figure 7.179) or for removal of broken bucket handle tears (Figure 7.180). The cuts made to remove bucket handle tears can be smooth without fraying (Figure 7.181) but more commonly are frayed or irregular and require debriding after the bucket handle has been removed (Figure 7.182). This is done

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Figure 7.170  Incompletely removed remnants of the origin of the cranial cruciate ligament on the medial aspect of the lateral femoral condyle. Telescope and patient orientation are the same as in the previous image. The caudal cruciate ligament is on the far left, the axial surface of the lateral femoral condyle is on the far right, remnants of the origin of the cranial cruciate ligament are in the center, and tibial plateau fills the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.172  Removing chronic ruptured cranial cruciate ligament remnants at the ligament insertion using a small side effect VAPR handpiece. Proximal is up in this image, and the telescope was inserted through a craniomedial portal with the electrode inserted through a craniolateral portal. Cruciate ligament remnants fill the lower left with the electrode coming from the right, and femoral condyle is visible in the upper background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

using hand instruments, the power shaver, or more commonly with radiofrequency (Figure 7.183) to produce a smooth surface (Figure 7.184). Damaged areas of the meniscus, other than bucket handle tears (Figure  7.66), are removed with hand instruments (Figure  7.185) or the power shaver for larger lesions (Figure 7.186) followed by radiofrequency to smooth and shape the resection margin (Figure 7.187). Small

Figure 7.171  Radiofrequency is used, when needed, to remove and smooth the ligament remnants after most of the ligament has been removed with the power shaver. This is the same patient as shown in Figure 7.169 with the same telescope and patient orientation showing the same anatomic structures. A 2.3 mm diameter wedge effect VAPR electrode is visible in the lower right that was used to remove and smooth the cruciate ligament tissue. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.173  Removal of chronic cranial cruciate ligament rupture remnants in a large dog at the ligament insertion using a large, 3.5 mm diameter, side effect VAPR handpiece. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

areas of meniscal damage (Figure 7.188) are managed with radiofrequency without prior shaving or use of hand instruments (Figure 7.189). Medial meniscal release is controversial but when indicated can be performed using arthroscopy in combination with TPLO or with other stifle stabilization procedures. Transection of the caudal tibial ligament of the medial meniscus is the preferred technique for meniscal release and has most commonly been done using radiofrequency. The caudal tibial ligament of the medial meniscus is visible cranial to the caudal cruciate ligament (Figures 7.25 and Figure 7.26) and can be

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.174  Placing a duckbill meniscus cutter at the axial end of a medial meniscus bucket handle tear. The telescope is looking caudally in the intercondyloid fossa from a craniolateral portal with the instrument inserted through a craniomedial portal. Portals were switched to provide better instrument access to the medial meniscus. Proximal is up, and medial is to the left. The medial femoral condyle fills the upper right, the tibial plateau is visible at the bottom and the crushed bucket handle extends from the far right into the open jaws of the meniscus cutter. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.176  The cut at the end of the bucket handle tear made with the duckbill meniscus cutter seen in the previous figure. Proximal is up on the image, and the telescope is looking caudomedially from a craniomedial portal with the femoral condyle at the top, the tibial plateau at the bottom, and the damaged axial margin of the medial meniscus running horizontally across the field of view. The cut is at the center with the meniscus on the right and the end of the bucket handle on the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.175  The duckbill meniscus is placed cutter on the medial meniscus at the abaxial end of a bucket handle tear in proper position to cut the bucket handle attachment. Dorsal or proximal is up on the image with medial to the right. The telescope is in a craniomedial portal with the instrument in a craniolateral portal. A thin sliver of medial femoral condyle is visible in the upper right, the tibial plateau is at the bottom left, and the damaged axial margin of the medial meniscus is extending from the lower right to the closed jaws of the instrument at the start of the bucket handle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.177  Grasping the freed end of a bucket handle tear using a duckbill meniscus cutter. Proximal is up, and medial is to the right with the medial femoral condyle in the upper left, the instrument to the right inserted through a craniomedial portal, damaged bucket handle tissue in the lower left, and reactive synovial tissue in the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.178  Removing a freed bucket handle tear with rongeurs. Note that the thick end of the rongeurs interferes with access for a good grip on the damaged tissue and that the instrument is rotated slightly to facilitate opening. Proximal or dorsal is up, and the medial femoral condyle fills the upper half of the image. The instrument is inserted through a craniomedial portal, and the telescope was moved to the craniolateral portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.180  Removing a broken bucket handle tear with a power shaver using a 2.5 mm aggressive cutting blade. The shaver blade is to the left with meniscal tissue extending horizontally across the middle of the image, femoral condyle is at the top, and tibial plateau is at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

accessed with a shaped small side effect VAPR handpiece (Figure 7.190) that is bent about 30° toward the electrode and the ligament transected making sure that the cut is complete with no residual stands (Figure 7.191). The caudal meniscotibial ligament can

Figure 7.179  Removing a bucket handle tear that has had one end freed with the meniscus cutter using the power shaver with a 2.5 mm aggressive cutting blade. The opening of the outer cannula of the shaver blade is in the lower right with bucket handle meniscal tissue to the left. The meniscal tissue is blurred due to movement of the shaver. Proximal is up, and a small portion of femoral condyle is visible in the background at the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.181  A clean residual cut end following removal of a bucket handle tear that does not require revision. Proximal is up, and medial is to the right. The cut is at the craniomedial end of the bucket handle. The telescope is looking caudomedially from a craniomedial portal. The medial femoral condyle fills the top left, the meniscal cut is at center right with the residual meniscus extending to the right from the cut, tibial plateau is in the lower left, and hyperemic synovial tissue is in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

also be cut with a number 11 scalpel blade (Figure  7.192), an arthroscopic hook knife (Figure 7.193), or with an 18 gauge hypodermic needle (Figure  7.194). In joints with minimal cruciate ligament injuries having no drawer instability access to

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.182  A frayed residual cut end following removal of a bucket handle tear that requires debriding. The telescope is looking caudomedially from a craniomedial portal with medial to the right and proximal or dorsal up. The medial femoral condyle fills the upper left of the image with reactive synovial tissue to the far right, tibial plateau in the lower right, and the frayed cut end of a bucket handle tear protruding up from the meniscal cut that is outside the field of view. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.184  The cut end shown in the previous two images after smoothing with the VAPR. Orientation, telescope position, and visible anatomic structures are the same as in the previous image. The smooth surface of the meniscal cut is seen at the far right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

the meniscotibial ligament is difficult and meniscal release is not performed. Midbody meniscal release was the technique first used with TPLO surgery. This technique is no longer recommended as it violates the principles of meniscal surgery. Originally, this technique was performed blindly but is better performed with arthroscopic guidance. A 20 gauge

Figure 7.183  Smoothing the cut end seen in the previous image using the VAPR with a small side effect electrode. The electrode is seen entering the bottom of the frame from a craniomedial portal with the telescope looking caudomedially from a craniolateral portal. The medial femoral condyle fills the upper half of the image with the meniscus to the far-right center and the electrode is in contact with the cut surface of the meniscus. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.185  Removing the damaged portion of the meniscus seen in Figure 7.66 using a duckbill meniscus cutter. The telescope is looking caudomedially from a craniolateral portal, and the instrument is inserted through a craniomedial portal. Proximal or dorsal is up, and medial is to the left. The dorsal surface of the cranial pole of the medial meniscus is seen crossing the lower image with the axial margin accentuated by the pannus on the meniscus but not on the underlying tibial plateau. Pannus is present on the tibial plateau to the far right. A small portion of femoral condyle is visible at the top of the image with the frayed damaged meniscus coursing across the image between the condyle and tibia. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.186  Removing a large area of damaged meniscus using the power shaver with a 3.5 aggressive cutting blade. The shaver blade is in the background, and damaged meniscal tissue is in the foreground. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.188  Preparing to remove the area of damaged axial margin of the lateral meniscus seen in Figure 7.162 using radiofrequency. Care is taken to prevent damage to the adjacent cartilage surfaces by rolling the small wedge effect VAPR electrode so that the active portion of the electrode is up against the meniscus and the ceramic shield is down against the articular cartilage. The telescope is looking caudally from a craniolateral portal with the electrode inserted through a craniomedial portal. Proximal or dorsal is up, and lateral is to the right. The lateral femoral condyle fills the upper half of the field of view with the lateral meniscus at the bottom extending to the right into the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.187  Completed resection of the area of damaged medial meniscus seen in Figures 7.66 and Figure 7.185 after revision with radiofrequency. The telescope is looking caudally through the intercondyloid fossa from a craniolateral portal between the tibial plateau at the bottom and the medial femoral condyle at the top. The smoothed resection surface of the caudal pole of the medial meniscus is visible extending horizontally across the middle of the image. The peripheral margin of the caudal pole of the meniscus was left in place as it was well attached caudally. Proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.189  Completed removal of the meniscal lesion seen in Figure 7.162 and in the previous image. Orientation, telescope position, and anatomic structures are the same as in the previous image. The damaged portion of the axial margin of the lateral meniscus has been resected leaving a clean smooth margin. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

1″ or 1.5″ hypodermic needle is inserted caudal to the medial collateral ligament into the joint to establish the optimum incision site (Figure  7.195). A no. 11 scalpel blade is inserted at the same site of the needle and at the same angle so that it is positioned across the medial

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.190  The caudal meniscotibial ligament of the medial meniscus is most easily cut with radiofrequency using a small, 2.3 mm diameter, side effect VAPR electrode. The electrodes shafts are malleable, and the tip is bent about 30° toward the electrode side to provide a better angle for application of the electrode to the ligament. The electrode is positioned caudal to the ligament, energy is applied, and the electrode is moved cranially to transect the ligament. The telescope is looking caudally from a craniomedial portal with the electrode inserted through a craniolateral portal. Proximal or dorsal is up, and medial is to the left. The ligament is in the center of the image with its insertion on the right and transition to the meniscus to the left. A small portion of caudal cruciate ligament is visible at the top of the image with tibial plateau at the bottom, and a small portion of medial femoral condyle in the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.191  Completed transection of the caudal tibial ligament of the medial meniscus using radiofrequency as shown in the previous image. Telescope position, orientation, and anatomic structures are the same as in the previous image. The cut surface of the ligament is visible on the origin end on the right with separation of the cut ends and a clear view indicating that there is no uncut ligament tissue. The cranial surface of the caudal cruciate ligament is visible deep to the transected ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.193  Cutting the caudal meniscotibial ligament with an arthroscopic hook knife. This technique has the disadvantage that reusable knives dull easily making transection of the ligament difficult. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.192  Cutting the caudal tibial ligament of the medial meniscus using a no. 11 scalpel blade. A hook probe is positioned distal to the blade to aid in placement. This technique has the disadvantage that no. 11 blades are straight, and positioning can be difficult. Number 11 scalpel blades are also easily broken in this application. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

meniscus (Figure 7.196). Observation with arthroscopy is used to make the incision and to confirm that the meniscus is completely transected. The stifle is routinely reexamined following corrective cruciate ligament surgery to confirm adequate removal of cruciate ligament remnants, adequate meniscal debridement, and adequate meniscal release if performed. The change in tibial plateau position

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produced by a TPLO also changes the visual angle of the joint allowing a different perspective and different access to intra-articular structures. Examination of the joint also looks for the occasional inadvertently placed intra-articular screw (Figure 7.197).

7.5.2  Caudal Cruciate Ligament Injuries In the authors’ experience significant injuries to the caudal cruciate ligament are rare. Caudal cruciate ligament injuries are commonly associated with trauma causing multiple ligament injuries as opposed to the idiopathic onset of cranial cruciate ligament injuries (Hulse and Shires 1986). Mild fraying of the caudal cruciate ligament can be seen with cranial cruciate ligament injuries and is not felt to be clinically significant. Splitting of caudal cruciate ligament fibers is seen (Figure 7.198) but is commonly associated with cranial cruciate ligament injuries. Cross striations seen in caudal cruciate ligament fibers are not an indication of caudal cruciate injury but do indicate that tension has been taken off the ligament most commonly due to cranial cruciate ligament injury (Figure  7.199). Pannus occasionally seen on the surface of the caudal cruciate ligament is also most commonly due to cranial cruciate ligament injury (Figure 7.72). Little attention has been paid to caudal cruciate ligament injuries with causes, effects, corrections, and the relationship to cranial cruciate ligament injury is poorly understood (Harari et al. 1987, 1993; Johnson and Olmstead 1987; Pournaras and Symeonides 1983; Reinke 1982; Zachos et al. 2002).

Figure 7.194  Cutting the caudal tibial ligament of the medial meniscus using an 18-gauge hypodermic needle. The advantages of this technique are that hypodermic needles are very sharp, are inexpensive, are disposable, the needle can be bent to facilitate access to the ligament and is also rigid enough to resist bending while cutting the ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

One publication finding a high incidence of injury associated with cranial cruciate ligament injury suggests that these injuries are “underappreciated” (Sumner et al. 2010). Avulsion of the origin of the caudal cruciate ligament from the lateral aspect of the medial femoral condyle is occasionally seen in young dogs (Soderstrom et al. 1998). If the fragment is large and the ligament is otherwise intact the fragment can be reduced and stabilized with arthroscopic or open technique. If the fragment is small, is in multiple pieces, or if the caudal cruciate ligament is damaged, removal is performed. When a diagnosis of caudal cruciate ligament injury is made complete examination of the stifle joint is conducted to rule out meniscal injuries, collateral ligament injuries, and cranial cruciate ligament injuries.

7.5.3  Isolated Meniscal Injuries Meniscal injuries are commonly seen with cruciate ligament injuries whether partial or complete, but meniscal injuries are very rare in dogs in the absence of cruciate ligament injuries (Adams et al. 2018; Ridge 2006). The cases of isolated meniscal injuries seen by the author were early in application of arthroscopy and more likely were missed cruciate ligament injuries.

Figure 7.195  Midbody medial meniscal release is performed with a radial midbody incision guided by arthroscopic placement of a hypodermic needle caudal to the medial collateral ligament. The needle is directed craniolaterally and aligned with arthroscopic assistance across the body of the medial meniscus. The image is rotated slightly so that proximal is to the upper left and medial is to the upper right. The telescope is looking caudomedially from a craniomedial portal, and the needle is placed across the width of the meniscus in a craniolateral direction. The medial femoral condyle fills the upper left of the image with the dorsal surface of the medial meniscus filling the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.196  A number 11 scalpel blade is inserted at the same site and in the same orientation as the needle to transect the body of the medial meniscus. Orientation, telescope placement, and anatomic structures are the same as in the previous image. The no. 11 blade is visible with the sharp edge facing down cutting the body of the meniscus. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.198  Splitting of the caudal cruciate ligament fibers is seen indicating pathology in the stifle of a dog with a cranial cruciate ligament rupture. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.197  A screw that was inadvertently placed into the cranial compartment of the stifle joint during TPLO surgery and was found when the arthroscope was reinserted after the procedure had been completed but prior to closure. The telescope is inserted through a craniomedial portal, proximal is up, and medial is to the right. The screw is protruding into the fat pad with medial femoral condyle visible in the upper background and tibial plateau in the lower background. The screw was removed, and a shorter screw placed. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5.4  Osteochondritis Dissecans(OCD)

Figure 7.199  Visible cross striations in the caudal cruciate ligament due to loss of normal ligament tension secondary to a cranial cruciate ligament injury. There is also splitting of the ligament fibers. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

The stifle joint is an uncommon but defined location for OCD and lesions typically occur on the lateral condyle of the femur in young large breed dogs (Bertrand et al. 1997; Montgomery et al. 1989). OCD lesions may also be seen on the medial femoral condyle, and bilateral lesions are common. Diagnosis may not be made until dogs are older than the typical presentation interval for OCD in other joints. Signalment, history, and physical findings are insufficient to establish a diagnosis

but localization to the stifle joint can typically be achieved. Radiographs showing a condylar defect are diagnostic but absence of a visible lesion in the presence of joint effusion does not rule out OCD and is a sufficient indication for arthroscopy. Bilateral radiographs are recommended, even with no other evidence of bilateral involvement, and bilateral arthroscopy is pursued if there is any evidence of pathology in the contralateral

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asymptomatic stifle. CT of the stifles is also helpful in making a preoperative diagnosis. Arthroscopy for stifle OCD is performed with the patient in dorsal recumbency (Figure 2.9) with a craniomedial telescope portal, craniolateral operative portal, and a suprapatellar egress portal (Figure  7.4). OCD lesions are typically easily visible on the medial aspect of the central portion of the lateral femoral condyle as a loose flap of cartilage with easily defined margins (Figure 7.200). They also appear as soft or movable cartilage with poorly defined margins (Figure  7.201), as a frayed cartilage defect without an identifiable loose cartilage fragment (Figure 7.202), or as irregular cartilage without loose cartilage (Figure 7.203). Free OCD cartilage or osteocartilaginous fragments are seen with single (Figure  7.204) or multiple (Figure  7.205) fragments in situ, with displaced free fragments in some other location in the joint including the suprapatellar pouch (Figure  7.206), the medial or lateral joint spaces (Figure  7.207), and in the cranial joint compartment (Figure 7.208). These free fragments must be found and removed. OCD lesions are seen with small areas of fullthickness cartilage loss (Figure 7.209) and lesions with loss of large areas of cartilage (Figure 7.210) but where no free fragments could be found in the joint. Villus synovial proliferation occurs with OCD in the stifle but is typically less than is seen with cruciate ligament injuries and is more localized to the area over the OCD lesions.

Figure 7.200  An OCD lesion on the lateral condyle of the femur with a loose cartilage fragment having a well-defined margin. The telescope is looking caudally from a craniomedial portal with medial to the left and proximal or dorsal up. The loose cartilage of the lesion is in the upper foreground with the caudal margin visible as the defect running caudally across the middle of the image. Tibial plateau is at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Partial fat pad resection and cranial compartment partial synovectomy are performed as needed to improve visualization of the femoral condyles and OCD lesions. Flexion of the joint is also required to bring the lesion into view and to provide access for flap removal and bed debridement. Manipulation of partially attached OCD cartilage is performed with the hook probe as needed to free the involved cartilage (Figure  7.211). Removal of the free flap is performed with a curved mosquito hemostat (Figure 7.212), with arthroscopic grasping forceps, or with arthroscopic rongeurs (Figure 7.213) using technique similar to that for shoulder joint OCD. The cartilage defect is evaluated for residual loose cartilage fragments, and the margin of the lesion is palpated with a hook probe for any remaining detached cartilage which is removed with hand instruments leaving a clean attached cartilage perimeter (Figure  7.214). The bed of the lesion is gently debrided to expose bleeding bone using hand instruments (Figure 7.215). Use of the shaver is not recommended as it is too easy to remove an excessive amount of bone. Microfractures can be created in the debrided bed to enhance healing when indicated. The joint is irrigated thoroughly, and all compartments of the joint are examined for any residual loose fragments. At completion of the procedure, instrumentation is removed and closure is with individual skin sutures at each portal site.

Figure 7.201  A large OCD lesion in the lateral condyle of the femur with loose cartilage and poorly defined margins. The dark area at the top of the image is the indistinct cranial margin of the lesion with no visible margin around the remainder of the lose cartilage. Elevation of the center portion of the free cartilage was evident at the time of the procedure but is not appreciated in this image. Proximal, or dorsal is up, and the telescope is looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.202  An OCD lesion in the medial condyle of the femur with frayed cartilage but no loose fragment. This is Grade IV chondromalacia but because of its location it was diagnosed as OCD. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up on the image. The medial femoral condyle fills the upper half of the figure with the lesion in the center and tibial plateau is visible across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.204  A single free femoral condyle osteocartilaginous OCD fragment in situ. The femoral condyle fills the field of view with a small area of tibial plateau visible at the lower left. Proximal is up, and the telescope is looking caudally from a craniomedial portal. The free fragment is part of the OCD defect, and additional loose cartilage was present surrounding the exposed bone seen behind the free fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.203  An OCD lesion in the medial condyle of the femur with irregular attached cartilage and no free fragment. Up is proximal or dorsal and the telescope is looking caudally from a craniomedial portal. The medial femoral condyle fills the image with a small portion of tibial plateau at the bottom, and the OCD lesion covers the majority of visible condyle surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.205  Multiple free femoral condyle osteocartilaginous OCD fragments. This lesion is on the axial margin of the lateral femoral condyle with proximal up and medial to the right. The small free fragments visible in the lower right are completely detached, and a larger loose cartilage flap that is attached at its lateral margin fills the left half of the field. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.206  A displaced free remodeled OCD fragment in the suprapatellar pouch. The telescope is looking proximally from a craniomedial portal and up on the image is cranial. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.208  A small displaced free remodeled OCD fragment in the cranial joint space. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up. The free fragment fills the upper center of the picture with reactive fat pad on the left and irregular tibial plateau cartilage on the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Lesions suspicious of OCD have been seen infrequently as an incidental finding during arthroscopy for management of cranial cruciate ligament injuries. The significance of these lesions is not known, and it has not been determined if these are truly old untreated OCD lesions or if the cartilage damage is secondary to the cranial cruciate ligament injury. A wide range of appearance occurs with these lesions. Femoral condyle defects are seen that are covered with smooth normal-appearing cartilage commonly with pannus within the depth of the lesion (Figures 7.63 and 7.66), with fibrillated car-

Figure 7.207  A large displaced free remodeled OCD fragment in the lateral joint compartment. Cranial is up on the image with lateral to the left, and the telescope is looking proximally from a craniomedial portal. The free fragment fills the center of the image, an egress cannula is to the left, and the lateral surface of the femoral trochlea is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.209  An OCD lesion in the lateral femoral condyle with areas of full-thickness cartilage loss. No free fragments were found in the joint. Proximal or dorsal is up, the telescope is looking caudally from a craniomedial portal with femoral condyle filling most of the upper portion of the image, a small area of tibial plateau across the bottom, the lesion in the center, and an avascular synovial frond extending across in front of the cartilage defect. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

tilage (Figure 7.121), fragmented cartilage (Figure 7.126), and well-attached irregular cartilage with Grade IV defects (Figure 7.125). Results with arthroscopic management of stifle OCD have been determined to be better than with open

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.210  A femoral condyle wear lesion with a large area of cartilage loss and exposed eburnated bone, Grade V chondromalacia, from an undetermined etiology. A central depressed area with residual fibrillated cartilage represents the actual OCD lesion. No free fragments could be found in the joint. The telescope is looking caudally from a craniomedial portal and up is proximal on the image. The femoral condyle almost completely fills the field of view with a small area of meniscus across the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.212  Removing a free OCD cartilage flap with a curved mosquito hemostat. The telescope is looking caudally from a craniomedial portal, and the instrument was placed through a craniolateral portal directly over the lesion. With joint flexion needed to expose the OCD lesions, there is restricted space that limits visualization. Proximal is up on the image. The hemostat is seen grasping the free cartilage fragment with exposed bone of the lesion bed indistinctly visible in the background above the free cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

surgical procedures but is still not as good as is desired. Stem cell therapy at the time of arthroscopic surgery is indicated. Using stem cells injected under free cartilage fragments have been considered to promote reattach-

Figure 7.211  Using a hook probe to free a loose OCD cartilage flap before removal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.213  Removing a free OCD cartilage flap with arthroscopic rongeurs. Proximal is up, and the telescope is looking caudally from a craniomedial portal with the instrument passed through a craniolateral portal directly over the lesion. The femoral condyle fills the upper right with the lesion bed to the left of center above the instrument and the free cartilage flap extends from the lower right into the rongeur jaws. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

ment of the loose cartilage but has not been documented to be effective. Osteocartilaginous grafts using the OATS technique has been employed for management of stifle OCD but is currently performed as an open procedure (Cook et al. 2008; Fitzpatrick et al. 2012). Second-look arthroscopy after OATS procedures has revealed significant chondromalacia in the implanted cartilage.

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Figure 7.214  A femoral condyle OCD lesion following debriding with hand instruments with a clean attached cartilage margin. Proximal is up with exposed bone of the lesion bed at the top, the cartilage margin of the lesion below the exposed bone, a narrow band of cartilage next, with the dorsal surface and axial margin of the lateral meniscus, and the tibial plateau at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.215  An OCD lesion on the medial aspect of the lateral femoral condyle after cartilage flap removal and debridement of the bed and margins of the lesion. Dorsal or proximal is up, and medial is to the left, and the telescope is looking caudally from a craniomedial portal. The femoral condyle fills the upper portion of the image with the lesion to the left of center, and a small area of tibial plateau is visible at the bottom. The margin of the lesion is irregular with a narrow band of normal cartilage surface at the far lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5.5  Stifle Stabilization Failures Second-look arthroscopy has most commonly been performed for failure of stifle stabilization techniques. Fascial strip implants when matured appear very similar to normal cruciate ligaments (Figure 7.216). Loss of integrity is visualized with the same appearance of both acute (Figure  7.217) and chronic (Figure  7.218) cruciate ligament injuries. Removal of the compromised fascial strip tissue is performed with the same technique as is used for cruciate ligament debridement. Histopathology of removed fascial strip tissue has revealed findings identical to ruptured cruciate ligament tissue. Examination of failed intra-articular implants is effective using arthroscopic technique (Figure 7.219) with removal achieved in most cases (Figure 7.220). Arthroscopy was used for joint management with failed Gore-Tex cruciate ligament prostheses (Figure 7.221). These prostheses are no longer used due to the high failure rate. Arthroscopic assessment of stifle joints with failed extracapsular techniques is also employed to define, debride, and manage intra-articular pathology. Meniscal assessment is important in evaluation of these cases because a significant portion of symptoms associated with technique failure is related to meniscal damage that has occurred since the initial repair (Figure  7.222). This is especially important with inadequate results following TPLO surgery that is commonly associated with meniscal injuries. An interesting finding with second-look arthroscopy due to failure of previous repair techniques is that there is little or no villus synovial

reaction (Figure 7.223) even in the presence of significant pain and instability. The only exception to this finding is with a failed Tight Rope procedure when the implant is placed in the joint or has eroded into the joint and marked synovial reaction is seen (Figure 7.224).

7.5.6  TPLO Second Look Arthroscopy following TPLO surgery is most commonly performed for recurrent lameness, and this is most commonly due to meniscal injury that can take all forms of the damage that occur with cranial cruciate ligament ruptures prior to surgery. Occasionally second-look arthroscopy is performed as a learning experience without any other medical indication at the time of a second side stifle surgery or at the time of implant removal. In cases with early partial cranial cruciate ligament injuries and no instability, healing of the cranial cruciate ligament can occur (Figure  7.225). The villus synovial reaction has been seen to completely resolve (Figure  7.226) or leave villus ghosts (Figure  7.227). Osteophytes, if present, do not resolve (Figures  7.226 and  7.227). Injuries to both the medial (Figure  7.228) and lateral (Figure 7.229) menisci are seen but in joints with early partial tears with no instability do not appear to progress.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.216  A mature fascia lata strip in the stifle of a dog with mild compromise and drawer instability due to failure of the stabilization technique. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up and medial to the right. The fascial strip is coursing from caudolateral to craniomedial in the same position as a cranial cruciate ligament with an appearance similar to the ligament. On the far right a small portion of caudal cruciate ligament is visible with the axial surface of the lateral femoral condyle on the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.218  Ruptured strands of a fascial strip having the same appearance as a chronic ruptured cranial cruciate ligament with both acute and chronic injured strands. The telescope is looking caudally into the intercondyloid fossa, proximal is up, and lateral is to the right. Intact caudal cruciate is visible in the upper left with acutely, chronically ruptured strands in the center, intact fascial strip indistinctly to the right, and a narrow band of the axial surface of the lateral femoral condyle on the far right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.217  Ruptured strands of a fascial strip having the same appearance as acute ruptured cranial cruciate ligament strands. Proximal or dorsal is up, and the telescope is looking caudally from a craniomedial portal. Villus synovial reaction is seen at the bottom of the image in the foreground with ruptured fascial strands protruding into the joint space and femoral condyle is in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.219  A broken intra-articular strand of no. 5 Mersilene suture and ruptured fascial strip identified using arthroscopy at the time of reoperation for a failed intracapsular stabilization. Mersilene was used to support fascial strips during the healing phase in combination with a fibular head transplant. Use of intra-articular braded suture is not recommended by many surgeons due to formation of draining fistulas but this did not occur in the authors experience. Only one draining fistula occurred in over 1000 surgeries, and in this case, the patient removed skin staples and three layers of sutures to open the joint in the immediate postoperative period. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.220  Removal of broken intra-articular Fiber Wire in a failed tight-rope procedure where the suture eroded into the joint. The suture was grasped with 3.5 mm arthroscopic rongeurs and removed. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.222  Fraying of the axial margin of the lateral meniscus seen during second-look arthroscopy for a failed Tight Rope stabilization. Proximal is up on the image with the lateral femoral condyle filling the top of the image, the tibial plateau in the lower right, and the shredded meniscus horizontally across the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5.7  Patellar Fracture Management Patellar fracture management is facilitated with arthroscopy for assisting fracture reduction or removing small nonstructural fragments. For fracture reduction, arthroscopic-assisted technique is employed using arthroscopy to visualize the articular surface of the fracture (Figure 7.230) and open exposure of the cranial surface of the patella is employed for implant placement. The patient is placed in dorsal recumbency, and standard

Figure 7.221  A ruptured Gore-Tex prosthesis that was removed at the time of reoperation. The broken end of the prosthesis is visible as the yellow material in the center of the image with the caudal cruciate ligament on the right and the axial surface of the lateral femoral condyle to the left. An area of tissue surface treated with the VAPR is visible in the lower right. Proximal or dorsal is up with medial to the right, and the telescope is looking caudally from a craniomedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.223  Second-look arthroscopy following failure of an extracapsular repair with no synovial reaction even in the presence of significant pain and instability. Residual villus ghosts are present in the center of the image as vertical irregular white bands. A small area of fat pad is seen at the far right with a small area of blood. Proximal is up, and femoral condyle is indistinctly visible in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

arthroscopy portals are employed. If the joint is opened for fracture reduction or by the injury the telescope is used in the open joint. Arthroscopic resection of patellar fragments has also been reported (Bright and May 2011).

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.224  Marked villus synovial reaction seen at second-look arthroscopy in a joint with a failed intra-articular Fiber Wire. Villus synovial reaction in joints with failed cranial cruciate ligament surgeries is uncommon, especially with this severity, and the appearance in the previous image is more typical. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.225  A healed cranial cruciate ligament seen at second-look arthroscopy following TPLO surgery for an early partial ligament injury with no joint instability. This was a totally normal-appearing joint with normal cruciate ligaments, normal menisci, normal cartilage surfaces, and no villus synovial reaction. The image is slightly obliqued with proximal to the upper left with medial to the upper right and the telescope is looking caudally from a craniomedial portal. The cranial cruciate ligament is seen running obliquely directly away from the telescope with smooth tight fibers. The caudal cruciate ligament is running vertically on the right with smooth tight fibers. The lateral femoral condyle is on the left. There is no villus reaction or hyperemia in the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.226  The medial joint space of a case seen at second-look arthroscopy following TPLO surgery for an early partial cranial cruciate ligament injury with complete resolution of villus synovial reaction. The joint capsule on the left is smooth with no inflammation or villus synovial reaction. Osteophytes present on the medial surface of the femoral trochlea on the right are unchanged from the time of original surgery with no progression or resolution. The telescope is looking proximally from a craniomedial portal with cranial up and medial to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.227  Residual villus ghosts in the suprapatellar pouch seen at second-look arthroscopy following TPLO surgery for an early partial ligament injury with minimal joint instability. The telescope is looking proximally from a craniomedial portal with cranial up. Osteophytes at the proximal end of the tracheal groove in the bottom of the image are unchanged from their preoperative size. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.228  Residual mild fraying, without progression, of the axial margin of the medial meniscus seen at second-look arthroscopy following TPLO surgery for an early partial cranial cruciate ligament injury with minimal joint instability. Proximal is up, and medial is to the right with the medial femoral condyle filling the top half of the image with tibial plateau visible in the lower left and the arc of the medial meniscus between the two bones. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.229  Residual mild fraying, without progression, of the axial margin of the lateral meniscus seen at second-look arthroscopy following TPLO surgery for an early partial cranial cruciate ligament injury with minimal joint instability. Proximal is up, and lateral is to the right. The lateral femoral condyle is to the upper right, the cranial pole of the lateral meniscus is in the lower right extending to the bottom across to the lower left, tibial plateau is visible in the center, and the caudal cruciate ligament is in the upper left. The axial margin of the meniscus courses in an arc between the bones and near margin shows an area of fraying. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5.8  Long Digital Extensor Tendon Injuries

Figure 7.230  The articular surface of a transverse patellar fracture viewed from a craniomedial telescope portal. The telescope is looking proximally from a craniomedial portal with the image obliqued to the left so that cranial is to the upper left. The proximal patellar fragment is seen in the upper left background, and the trochlear groove is to the lower right. The fracture surface is obscured with a hematoma and the distal segment with attached hematoma is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Avulsion of the origin of the long digital extensor tendon from its femoral attachment, partial tears, or complete ruptures are an uncommon but defined source of stifle joint pathology (Bardet and Piermattei  1983; Kennedy et  al.  2014; Lammerding et  al.  1976; Pond  1973). Partial or complete injuries without bone avulsion appear similar to bicipital tendon injures or cruciate ligament injuries with visible ruptured fibers and can be acute or chronic in appearance (Figure 7.231). Avulsed bone fragments can be seen radiographically, are typically small when acute, and can enlarge or disappear with time. The patient is placed in dorsal or lateral recumbency, and standard stifle portals are used. Treatment is tendon transection that is achieved with arthroscopy using radiofrequency (Figure 7.232). When transection is completed, the freed tendon end slides distally out of the joint (Figure 7.233).

7.5.9  Popliteal Tendon Avulsion Avulsion of the origin of the popliteal tendon from the lateral aspect of the femur is a rare injury, causing hind leg lameness (Bardet and Piermattei  1983; Bleedorn et  al.  2006; Eaton-Wells and Plummer  1978; Tanno

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.231  A partially avulsed long digital extensor (LDE) tendon with visible ruptured fibers at its origin. The tendon is shown pulled off the bone without any bone included in the avulsion. The telescope is looking laterally from a craniomedial portal with proximal or dorsal up and craniolateral to the right. The tendon is visible in the lower right with ruptured fibers visible along the left margin of the tendon. The origin of the LDE on the lateral aspect of the femoral condyle fills the left third of the image with fine ligament fibers covering its surface. Tendon fibers still attached to the femur are deep and are not visible. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.233  Completed transection of the origin of the partially avulsed LDE tendon in the case from the previous two figures. Residual tendon is attached to the bone with the cut proximal end visible on the left side of the picture. The freed distal end of the tendon is not visible as it has retracted distally out of the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

et al. 1996). This diagnosis can easily be missed because it is rare and, therefore, has a low index of suspicion. History and physical findings are similar to an early partial cranial cruciate ligament injury with lameness, stifle pain, and increased intra-articular fluid density but

Figure 7.232  Transection of the remaining attached fibers in the origin of partially avulsed LDE tendon seen in the previous figure using the VAPR with a small wedge effect electrode. Orientation of the telescope and anatomic structures are the same as the previous image. The active electrode, the black oval at the left end of the device, is applied to the tendon fibers and activation melts the tissue to transect the fibers and release the tendon from its attachment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

without drawer instability. A small free mineralized density is sometimes seen lateral to the lateral femoral condyle at the site of origin of the popliteal tendon. Absence of this radiographic finding does not rule out this diagnosis because the very small bone fragments can be missed and popliteal tendon injury without bone avulsion does occur (Figure 7.234). The free bone fragment can be easily seen with arthroscopy (Figure 7.235) and the bone fragment can be seen to move with flexion (Figure  7.235) and extension (Figure  7.236). Visualization is improved by placing the telescope into the joint through a craniolateral portal lateral to the patellar tendon. An operative portal is placed directly over the bone fragment, the tendon is cut off the bone with sharp dissection (Figure 7.237), and the loose bone chip is removed from the joint with small arthroscopic rongeurs (Figure 7.238) or graspers leaving the cut end of the tendon (Figure 7.239). The intra-articular portion of the tendon can be left in place or removed with radiofrequency (Figure 7.240). Exposed bone at the avulsion site is left alone, or microfractures are created to facilitate cartilage growth (Figure 7.241).

7.5.10  Intra-articular Neoplasia Intra-articular neoplasia is occasionally found during arthroscopic stifle exploration in cases of hind leg lameness, stifle pain, with or without stifle thickening or

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swelling, and with or without drawer instability. Radiographic changes may only be increased intra-articular soft tissue density or may demonstrate bony proliferation or lysis. In the absence of radiographic bony changes, these cases can appear identical to cranial cruciate ligament injuries with a definitive diagnosis only obtained with arthroscopy and lesion biopsy. Intraarticular neoplasia has a wide range of appearance depending on tumor type and the extent of tumor involvement. Early lesions appear as irregular synovial thickening (Figure 7.242) without villus formation typical of inflammatory lesions. Free strands of neoplastic tissue can also be seen (Figure 7.243). Neoplastic lesions also appear as white smooth avascular masses (Figure 7.244), irregular avascular masses (Figure 7.245), smooth vascular masses with small (Figure  7.246) to large (Figure 7.247) surface vessels, and irregular vascular masses with varied blood vessel quantity (Figure 7.248). Occasional tumors show fimbria formation with central blood vessels (Figure 7.249). Arthroscopy is also employed to obtain biopsies of distal femoral or tibial plateau bone lesions seen on radiographs and, in many cases, this will be a less traumatic approach for obtaining biopsies than open surgical technique.

7.5.11  Patellar Luxation

Figure 7.234  A partially ruptured or avulsed popliteal tendon on the lateral aspect of the femoral condyle seen with the telescope looking caudally from a craniolateral portal. Proximal or dorsal is up on the image, and medial is to the right. The disorganized tissue in the upper left is synovial reaction and ruptured tendon fibers with a portion of intact attached tendon visible at the very bottom, and the right side is filled with the lateral surface of the femoral condyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.235  An avulsed bone fragment at the origin of the popliteal tendon seen with the telescope looking caudally from a craniolateral portal. Proximal or dorsal is up, and medial is to the right. The joint is flexed in this image positioning the avulsed bone fragment over its sight of origin. The bone fragment fills the center of the image with the lateral aspect of the lateral femoral condyle on the right, tendon covered with reactive synovium on the left, and tibial plateau visible at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

In most cases, patellar luxation is not amenable to correction arthroscopically, but arthroscopy has been used by the author for evaluation of cartilage damage. Arthroscopic transection of the medial femoropatellar ligament (Bevan and Taylor 2004), medial patellar fibrocartilage, and medial retinaculum to release medial constraints on the patella that allow patellar realignment has been suggested for treatment of medial patellar luxation. There is inadequate information or case material available on this technique to determine longterm results, technique, or proper case selection criteria. Joint assessment before traditional open surgery is an indication for adding arthroscopy to the medial patellar luxation correction protocol (Figure 7.250). Arthroscopy has also been utilized for evaluation of traumatic lateral femoropatellar ligament rupture and for removal of a sequestered trochlear recession wedge.

7.5.12  Degenerative Joint Disease, Chondromalacia, and Synovitis Degenerative joint disease with associated cartilage and synovial changes is an unlikely primary diagnosis in the stifle joint of dogs and is most likely secondary to other

Figure 7.236  The avulsed bone fragment seen in the previous image with the joint extended. Telescope position and orientation are the same as in the previous image. Extension places traction on the popliteal tendon pulling the bone fragment caudally to expose bone at the avulsion site. The lateral aspect of the lateral femoral condyle is on the right with the area of exposed bone, the bone fragment fills the upper left, and tibial plateau is present in the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.238  The free bone chip is removed using 2.0 mm arthroscopic rongeurs. Telescope position and orientation are the same as in the previous images. The instrument is inserted through the lateral operative portal and is grasping the bone fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.240  The intra-articular portion of the tendon was ablated using the VAPR with a small wedge effect electrode. The telescope is positioned deep to the avulsion site extending along the lateral aspect of the femoral condyle into the caudal joint compartment. Proximal or dorsal is up, and caudolateral is to the left. The ablated end of the tendon is in the center of the image with caudal joint capsule on the left, femoral condyle in the upper right, and the abaxial surface of the lateral meniscus is in the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.237  An operative portal was established directly over the avulsed bone fragment, and the bone is cut away from the tendon using a no. 11 scalpel blade. The scalpel blade is seen behind the free bone fragment on the left side with bone fragment filling most of the image, a small sliver of femoral condyle is visible on the right, and tibial plateau is seen at the bottom. Telescope position and orientation are the same as in the previous figure. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.239  After the bone fragment had been removed. The sharp transection surface of the cut end of the tendon is on the left, exposed bone of the avulsion site is on the right, and tibial plateau is visible at the bottom. Orientation and telescope position are the same as in the previous images. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.241  Exposed bone at the avulsion site can be left as is or managed with microfracturing to facilitate cartilage growth. Since this is a non-weightbearing area microfractures to stimulate cartilage growth is probably not needed. The telescope position and orientation are the same as the previous figures showing identification and removal of the bone fragment. The microfracture chisel has been inserted through the lateral operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 7.242  Synovial cell sarcoma in a dog with a history, physical findings, including drawer instability, and radiographic changes identical to a ruptured cranial cruciate ligament. The telescope is looking proximally from a craniomedial portal into the medial joint compartment. There are no identifiable anatomic structures, and the entire synovial surface is covered with atypical tissue. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.244  Large smooth avascular intra-articular masses in the stifle joint of a dog with lameness, stifle joint pain, extensive joint swelling, and joint instability typical of a complete cranial cruciate ligament injury. Histopathology revealed this lesion to be a histiocytic sarcoma. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.246  Large smooth intra-articular neoplastic masses with a fine plexus of blood vessels. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.243  Multiple strands of tissue bridging the lateral joint space in the same patient as the previous figure. This abnormality has only been seen with synovial cell sarcoma. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.245  Irregular avascular intra-articular tissue masses completely obliterating any visible synovial tissue and representing a histiocytic sarcoma. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.247  Large smooth intra-articular neoplastic masses with a large blood vessel in the central mass in addition to many small blood vessels. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5  ­Diseases of the Stifle Joint Diagnosed and Managed with Arthroscop

Figure 7.248  Irregular intra-articular neoplastic tissue with variable amounts of visible blood vessels in different masses. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.250  Grade V chondromalacia on the caudal surface of the patella in a patient with chronic medial patellar luxation. The telescope is inserted through a craniomedial portal and is positioned looking proximally in the trochlear groove. Cranial is up. The patella fills the upper half of the image with exposed bone in the foreground and normal cartilage in the background. The trochlear groove covered with normal cartilage fills the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

defined joint pathology. If a primary cause is not obvious additional more thorough examination is warranted to definitively rule out early partial cranial cruciate ligament injuries, caudal cruciate ligament pathology, meniscal damage, long digital extensor tears, popliteal tendon ruptures, or other primary etiology.

Figure 7.249  Intra-articular neoplastic tissue that has formed fimbria with central blood vessels. This could potentially be confused with an inflammatory reaction. Whenever there is a question about the type of tissue in a joint take biopsies. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 7.251  A rarely seen discoid medial meniscus in the stifle of a dog with unrelated pathology. The telescope is looking caudally from a craniomedial portal with proximal or dorsal up and medial to the right. The femoral condyle fills the top of the picture, and the medial meniscus fills the bottom of the picture. There is no axial margin seen because the meniscus covers the entire interarticular space. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

7.5.13  Discoid Meniscus The discoid meniscus (Figure 7.251) is a rare finding in the dog and that is not associated with any known pathology. The occurrence of discoid meniscus in the human pediatric population is common (Dai et al. 2017; Kim et al. 2016; Kocher et al. 2017).

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7.5.14  Osteochondromatosis Intra-articular osteochondromatosis is a rare condition in dogs and presents as multiple free bony arthroliths that are amenable to removal with arthroscopy (Smith et  al.  2012). This condition has been diagnosed in the stifle (Díaz-Bertrana et  al.  2010; Smith et  al.  2012),

shoulder (Edinger and Manley 1998; Kunkle and Rochat 2008), and elbow (Aeffner et al. 2012). The small number of reported cases and lack of appropriate follow-up studies prevents accurate prognosis but reported cases of conversion to malignancy is concerning (Aeffner et al. 2012; Díaz-Bertrana et al. 2010).

­References Adams, RW. & Holmes, SP. et al. (2018) Magnetic resonance imaging diagnosis and arthroscopic treatment of medial meniscal injury in a dog with a palpably stable stifle. Can. Vet. J. 59, 654–8. Aeffner, F. & Weeren, R. et al. (2012) Synovial osteochondromatosis with malignant transformation to chondrosarcoma in a dog. Vet. Pathol. 49, 1036–9. Ashour, AE. & Hoffman, CL. et al. (2019) Correlation between orthopaedic and radiographic examination findings and arthroscopic ligament fibre damage in dogs with cruciate ligament rupture. Aust. Vet. J. 97, 490–8. Bardet, JF. & Piermattei, DL. (1983) Long digital extensor and popliteal tendon avulsion associated with lateral patellar luxation in a dog. J. Am. Vet. Med. Assoc. 183, 465–6. Bertrand, SG. & Lewis, DD. et al. (1997) Arthroscopic examination and treatment of osteochondritis dissecans of the femoral condyle of six dogs. J. Am. Anim. Hosp. Assoc. 33, 451–5. Bevan, JM. & Taylor, RA. (2004) Arthroscopic release of the medial femoropatellar ligament for canine medial patellar luxation. J. Am. Anim. Hosp. Assoc. 40, 321–30. Bleedorn, JA. & Towle, HA. et al. (2006) What is your diagnosis? Avulsion of the popliteal tendon. J. Am. Vet. Med. Assoc. 229, 1885–6. Bleedorn, JA. & Greuel, EN. et al. (2011) Synovitis in dogs with stable stifle joints and incipient cranial cruciate ligament rupture: a cross-sectional study. Vet. Surg. 40, 531–43. Bright, SR. (2010) Arthroscopic-assisted management of osteochondritis dissecans in the stifle of a cat. J. Small Anim. Pract. 51, 219–23. Bright, SR. & May, C. (2011) Arthroscopic partial patellectomy in a dog. J. Small Anim. Pract. 52, 168–71. Cook, JL. & Hudson, CC. et al. (2008) Autogenous osteochondral grafting for treatment of stifle osteochondrosis in dogs. Vet. Surg. 37, 311–21. Cusack, L. & Johnson, M. (2013) Arthroscopic assessment for patellar injuries and novel suture

repair of patellar fracture in a cat. J. Am. Anim. Hosp. Assoc. 49, 267–72. Dai, WL. & Zhang, H. et al. (2017) Discoid lateral meniscus. J. Knee Surg. 30, 854–62. Díaz-Bertrana, C. & Durall, I. et al. (2010) Extra- and intra-articular synovial chondromatosis and malignant transformation to chondrosarcoma. Vet. Comp. Orthop. Traumatol. 23, 277–83. Eaton-Wells, RD. & Plummer, GV. (1978) Avulsion of the popliteal muscle in an Afghan Hound. J. Small Anim. Pract. 19, 743–7. Edinger, DT. & Manley, PA. (1998) Arthrodesis of the shoulder for synovial osteochondromatosis. J. Small Anim. Pract. 39, 397–400. Ertelt, J. & Fehr, M. (2009) Cranial cruciate ligament repair in dogs with and without meniscal lesions treated by different minimally invasive methods. Vet. Comp. Orthop. Traumatol. 22, 21–6. Fehr, M. & Behrends, I. et al. (1996) Arthroscopic studies of the stifle of dogs. Tierarztl. Prax.. 24, 137–3. Fitzpatrick, N. & Yeadon, R. et al. (2012) Osteochondral autograft transfer for the treatment of osteochondritis dissecans of the medial femoral condyle in dogs. Vet. Comp. Orthop. Traumatol. 25, 135–3. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis. Fuller, MC. & Hayashi, K. et al. (2014) Evaluation of the radiographic infrapatellar fat pad sign of the contralateral stifle joint as a risk factor for subsequent contralateral cranial cruciate ligament rupture in dogs with unilateral rupture: 96 cases (2006-2007). J. Am. Vet. Med. Assoc. 244, 328–8. van Gestel, MA. (1985) Arthroscopy of the canine stifle. Vet. Q. 7, 237–9. Gleason, HE. & Hudson, CC. et al. (2020) Meniscal click in cranial cruciate deficient stifles as a predictor of specific meniscal pathology. Vet. Surg. 49, 155–9. Harari, J. (1993) Caudal cruciate ligament injury. Vet. Clin. North Am. Small Anim. Pract. 23, 821–9.

  ­Reference

Harari, J. & Johnson, AL. et al. (1987) Evaluation of experimental transection and partial excision of the caudal cruciate ligament in dogs. Vet. Surg. 16, 151–4. Hoelzler, MG. & Millis, DL. et al. (2004) Results of arthroscopic versus open arthrotomy for surgical management of cranial cruciate ligament deficiency in dogs. Vet. Surg. 33, 146–3. Hulse, DA. & Shires, P. (1986) Multiple ligament injury of the stifle joint in the dog. J. Am. Anim. Hosp. Assoc. 22, 105–10. Johnson, AL. & Olmstead, ML. (1987) Caudal cruciate ligament rupture: a retrospective analysis of 14 dogs. Vet. Surg. 16, 202–6. Kaufman, K. & Beale, BS. et al. (2017) Articular cartilage scores in cranial cruciate ligament-deficient dogs with or without bucket handle tears of the medial meniscus. Vet. Surg. 46, 120–9. Kennedy, KC. & Perry, JA. et al. (2014) Long digital extensor tendon mineralization and cranial cruciate ligament rupture in a dog. Vet. Surg. 43, 593–7. Kim, JG. & Han, SW. et al. (2016) Diagnosis and treatment of discoid meniscus. Knee Surg. Relat. Res. 28, 255–2. Kivumbi, CW. & Bennett, D. (1981) Arthroscopy of the canine stifle joint. Vet. Rec. 109, 241–9. Kocher, MS. & Logan, CA. et al. (2017) Discoid lateral meniscus in children: diagnosis, management, and outcomes. J. Am. Acad. Orthop. Surg. 25, 736–3. Kunkel KA and Rochat MC (2008) A review of lameness attributable to the shoulder in the dog: part two. J. Am. Anim. Hosp. Assoc. 44:163–70. Lammerding, JJ. & Noser, GA. et al. (1976) Avulsion fracture of the extensor digitorum longus muscle in 3 dogs. J. Am. Anim. Hosp. Assoc. 12, 764. McCready, DJ. & Ness, MG. (2016a) Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: part 1. J. Small Anim. Pract. 57, 59–66. McCready, DJ. & Ness, MG. (2016b) Systematic review of the prevalence, risk factors, diagnosis and management of meniscal injury in dogs: part 2. J. Small Anim. Pract. 57, 194–204. Mindner, JK. & Bielecki, MJ. et al. (2016) Tibial plateau levelling osteotomy in eleven cats with cranial cruciate ligament rupture. Vet. Comp. Orthop. Traumatol. 29, 528–5. Montgomery, RD. & Henderson, RA. et al. (1989) Osteochondritis dissecans of the canine stifle. Compend. Contin. Educ. Pract. Vet. 11, 1199. Neal, BA. & Ting, D. et al. (2015) Evaluation of meniscal click for detecting meniscal tears in stifles with cranial cruciate ligament disease. Vet. Surg. 44, 191–4. Plesman, R. & Gilbert, P. et al. (2013) Campbell J. detection of meniscal tears by arthroscopy and

arthrotomy in dogs with cranial cruciate ligament rupture: a retrospective, cohort study. Vet. Comp. Orthop. Traumatol. 26, 42–6. Pond, MJ. (1973) Avulsion of the extensor digitorum longus muscle in the dog: a report of 4 cases. J. Small Anim. Pract. 14, 785. Pournaras, J. & Symeonides, PP. (1983) The significance of the posterior cruciate ligament in the stability of the knee: an experimental study in dogs. J. Bone Joint Surg. 65, 204–9. Pozzi, A. & Hildreth, BE. 3rd. et al. (2008) Comparison of arthroscopy and arthrotomy for diagnosis of medial meniscal pathology: an ex vivo study. Vet. Surg. 37, 749–55. Ralphs, SC. & Whitney, WO. (2002) Arthroscopic evaluation of menisci in dogs with cranial cruciate ligament injuries: 100 cases (1999-2000). J. Am. Vet. Med. Assoc. 221, 1601–4. Reinke, JD. (1982) Cruciate ligament avulsion injury in the dog. J. Am. Anim. Hosp. Assoc. 18, 257–64. Ridge, PA. (2006) Isolated medial meniscal tear in a Border Collie. Vet. Comp. Orthop. Traumatol. 19, 110–2. Ritzo, ME. & Ritzo, BA. et al. (2014) Incidence and type of meniscal injury and associated long-term clinical outcomes in dogs treated surgically for cranial cruciate ligament disease. Vet. Surg. 43, 952–8. Ruthrauff, CM. & Glerum, LE. et al. (2011) Incidence of meniscal injury in cats with cranial cruciate ligament ruptures. Can. Vet. J. 52, 1106–10. Siemering, GH. (1978) Arthroscopy of dogs. J. Am. Vet. Med. Assoc. 172, 575–7. Smith, TJ. & Baltzer, WI. et al. (2012) Primary synovial osteochondromatosis of the stifle in an English Mastiff. Vet. Comp. Orthop. Traumatol. 25, 160–6. Soderstrom, MJ. & Rochat, MC. et al. (1998) Radiographic diagnosis: avulsion fracture of the caudal cruciate ligament. Vet. Radiol. Ultrasound 39, 536–8. Sumner, JP. & Markel, MD. et al. (2010) Caudal cruciate ligament damage in dogs with cranial cruciate ligament rupture. Vet. Surg. 39, 936–41. Tanno, F. & Weber, U. et al. (1996) Avulsion of the popliteus muscle in a malinois dog. J. Small Anim. Pract. 37, 448–51. Wustefeld-Janssens, BG. & Pettitt, RA. et al. (2016) Peak vertical force and vertical impulse in dogs with cranial cruciate ligament rupture and meniscal injury. Vet. Surg. 45, 60–5. Zachos, TA. & Arnoczky, SP. et al. (2002) The effect of cranial cruciate ligament insufficiency on caudal cruciate ligament morphology: an experimental study in dogs. Vet. Surg. 31, 596–603.

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8 Tibiotarsal Joint Arthroscopy of the tibiotarsal joint is indicated when there is hind leg lameness with pain, crepitus, swelling, or thickening of the tibiotarsal joint supported by radiographic changes suggestive of OCD, intra-articular fractures, degenerative joint disease, immune-mediated arthritis, or neoplasia (Cook et  al.  2001; Miller and Beale  2008). Tibiotarsal joint disease is commonly accompanied by significant joint swelling or thickening making localization of the involved joint easier than with more proximal joints. The tarsal joint is a recommended site for synovial biopsies for diagnosing immune-mediated polyarthritis.

8.1 ­Patient Preparation, Positioning, and Operating Room Setup Tibiotarsal joint arthroscopy is performed as a unilateral or bilateral procedure based on the pathology that is present. Dorsal recumbency is the most common position used for both unilateral and bilateral procedures. The legs are extended caudally and abducted or adducted for access to the medial or lateral aspects of the joint respectfully. The most common operating room arrangement is with a monitor at the head of the table (Figure  2.9). Alternative operating room setup places the monitor obliquely on either side of the table or when two monitors are used with one on each side of the table. Monitors on the sides are placed far enough cranially to be out of the way of the sterile operative field. The surgeon stands at the foot of the table and the assistant stands on the side of the table of the joint that is being examined. Tibiotarsal joint arthroscopy has been greatly improved by use of distraction (Rodriguez-Quiros et  al.  2014). The author uses a bolster under the joint to provide a fulcrum for distracting the facilitating access with the endoscope and instrumentation. For placement of plantar portals,

the patient can also be placed in ventral recumbency with the leg or legs extended off the caudal end of the table.

8.2 ­Portal Sites and Portal Placement 8.2.1  Telescope Portals All four quadrants of the tibiotarsal joint can be entered for arthroscopy. The portal selected for entry depends on the location of joint lesions. Telescope and operative portals are interchangeable at all sites. Dorsomedial and dorsolateral portals are placed either medial or lateral to the long digital extensor tendon and the tendon of the cranial tibial muscle on the dorsal aspect of the joint immediately distal to the distal margin of the tibia (Figure  8.1). To establish a dorsal tibiotarsal telescope portal at either of these sites, a 20-gauge 1″ needle is placed into the joint at the site of maximum joint capsule distension, joint fluid is aspirated, the joint is distended with saline, a stab incision is made with a no. 11 scalpel blade at the needle site, or on the other side of the extensor tendons if indicated, and the telescope cannula is placed into the joint using the blunt obturator. Plantaromedial or plantarolateral portals are placed at the junction of the plantar margin of the distal tibial articular surface and the plantar portion of the trochlear ridge of the talus on their respective sides of the joint (Figure 8.2). Plantar portals provide good access to plantar OCD lesions on the medial or lateral ridges of the talus and for removal of loose joint bodies from the caudal compartment of the joint. To establish a plantar tibiotarsal telescope portal, a 20-gauge 1″ needle is placed into the joint at the site of maximum joint capsule distension, joint fluid is aspirated, the joint is distended with saline, a stab incision is made with a no. 11

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

8.2  ­Portal Sites and Portal Placemen

Figure 8.1  Portal sites on the dorsal aspect of the tibiotarsal joint. The two portals shown (asterisks) are interchangeable telescope and operative portals. They are located distal to the dorsal margin of the distal tibial articular surface and are medial or lateral to the long digital extensor tendon, the tendon of the cranial tibial muscle, and the dorsal neurovascular bundle. Source: Modified from Freeman (1999) © John Wiley & Sons.

scalpel blade at the needle site, and the telescope cannula is placed into the joint using the blunt obturator. Joint capsule thickening secondary to joint pathology may make initial plantar joint entry difficult. In some cases with marked joint capsule thickening, the joint is entered with a mini-arthrotomy rather than a true telescope portal. A mini-arthrotomy is performed by making a stab incision through the skin, subcutaneous tissues, and joint capsule with a no. 11 blade to access the joint and the incision extended as needed. The telescope cannula is placed into the joint with the telescope already in the cannula, irrigation is initiated, and the joint is examined.

8.2.2  Operative Portals Access to OCD lesions on the plantar portion of the medial ridge of the talus, the most common indication for tibiotarsal arthroscopy, is most easily achieved through a medial operative portal placed distal to the malleolus and immediately caudal to the collateral ligament (Figure  8.2). Access to the joint is greatly facilitated by placing a bolster under the joint and opening the medial or lateral joint space by placing pressure on

Figure 8.2  Portal sites on the lateral aspect of the tibiotarsal joint. The plantarolateral, telescope portal (asterisk) is placed at the junction of the plantar margin of the distal tibial articular surface and the plantar portion of the lateral ridge of the talus. Lateral operative portals (square) are placed distal to the lateral malleolus and caudal to the collateral ligament. An egress portal or needle if needed is placed at the dorsolateral, telescope or operative portal site, shown in the previous figure. Medial portals are placed at the same respective locations on the medial aspect of the joint. Source: Modified from Freeman (1999) © John Wiley & Sons.

the tibia and metatarsal bones (Figures  8.3 and  8.4). Joint capsule thickening and limited space in the hock joint may preclude placing separate telescope portals and operative portals. In these cases, the telescope portal site is enlarged to serve as a combination portal with the telescope and instruments inserted through the same incision. On the dorsal aspect of the joint, the operative portal is established on the side of the extensor tendons not used for the telescope portal with initial needle placement for locating the portal site followed by a simple stab incision with a no. 11 blade through skin, subcutaneous tissue, and joint capsule. To place two portals in the plantar aspect of the joint, the patient is placed in ventral recumbency with an operative portal placed in the opposing corner of the joint from the telescope portal to achieve adequate access, visualization, and triangulation.

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8.3 ­Nerves of Concern with Tibiotarsal Joint Arthroscopy

Figure 8.3  The tibiotarsal joint visualized with the telescope in the plantaromedial portal without distraction over a bolster. The tibial articular surface is to the upper left and the talar articular surface fills the lower right of the image. Dorsal is to the upper left. Source: Timothy C. McCarthy. © John Wiley &Sons Inc.

The superficial and deep fibular nerves with the cranial tibial artery, the cranial branch of the saphenous artery, and the cranial branch of the saphenous vein all cross the dorsal aspect of the tibiotarsal joint (Figure 8.1). At the level of the tibiotarsal joint, the nerves are primarily sensory but do contain fibers that supply muscles in the paw. The combined neurovascular bundle with the tendons of the cranial tibial and long digital extensor muscles are palpated on the dorsal aspect of the joint and avoided when making these portals minimizing the possibility of nerve damage. The termination of the tibial nerve with the caudal branch of the saphenous artery cross the joint caudal to the tibia and medial to the calcaneus (Figure  8.2). These structures are caudal and lateral but close to the plantaromedial telescope portal and are at risk of injury. The operative portal for OCD lesions on the caudomedial ridge of the talus is on the medial aspect of the joint away from the dorsal and plantar neurovascular structures. The tibial nerve at this level is also primarily sensory but does supply motor fibers to muscles in the paw.

8.4 ­Examination Protocol and Normal Arthroscopic Anatomy

Figure 8.4  The tibiotarsal joint visualized from the same telescope position with distraction over a bolster. Note the increased joint space. Dorsal or proximal is to the left as is the tibial articular surface. The talar articular surface is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.2.3  Egress Portal A separate egress cannula is rarely used but if needed can be placed at any unused portal site. The very small space available in the tibiotarsal joint does not provide enough room for three cannulas, and egress is most commonly through the operative portal, through a mini-arthrotomy incision, or a through 20-gauge needle placed at an unused portal site.

Visible anatomy, structures used for orientation, and examination protocol vary with the portals that are used. The tibiotarsal joint is small, normally allowing minimal joint distraction for examination and manipulation. Varus or valgus angulation of the joint over a bolster greatly facilitates examination by opening the joint space and is strongly recommended. The joint capsule is too close to the bony structures of the joint to allow retraction of the arthroscope for a wide visual field. Multiple portals may be required for complete examination and operation of tarsal joint pathology. Orientation is established upon entering the tibiotarsal joint using the concave distal articular surface of the tibia and the ridges of the convex articular surface of the talus (Figures 8.3 and 8.4). Space within the tibiotarsal joint is limited and examination requires careful manipulation of the joint through flexion and extension with varus and valgus stress over the bolster using small movements of the telescope in depth, angle, and rotation. The distal articular surface of the tibia and the

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.5  The dorsal or cranial margin of the distal articular surface of the tibia is seen curving across the top of the figure and the proximal articular surface of the talus is seen filling the bottom of the image. The telescope is looking obliquely across the dorsal joint compartment from a dorsal portal. Proximal is up on the image and cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.6  The plantar aspect of the intra-articular portion of the lateral malleolus seen looking cranially from a plantarolateral telescope portal. Proximal is up on the image and lateral is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

proximal surface of the talus (Figures 8.3 and 8.4), the dorsal margin of the distal tibial articular surface (Figure 8.5), the lateral malleolus (Figure 8.6), and the accessible lateral (Figure  8.7), dorsal (Figure  8.8), and plantar (Figure 8.9) joint compartments are examined. The lateral head of the deep digital flexor tendon can be seen within the joint (Figure 8.10). Transferring the telescope among portal locations facilitates complete examination of the joint.

Figure 8.7  The lateral joint space seen between the distal articular surface of the tibia and proximal articular surface of the talus seen with the telescope looking laterally from a plantaromedial portal. Proximal is up and caudal is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.8  The dorsal tibiotarsal joint compartment with the joint capsule filling the majority of the image and the dorsal articular surface of the talus on the left seen looking across the joint from a dorsal telescope portal. Proximal is up and dorsal or cranial is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.5 ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscopy 8.5.1  Osteochondritis Dissecans (OCD) OCD is the most common arthroscopic diagnosis in the tibiotarsal joint and is the most common indication for operative arthroscopy of this joint (Cook et  al.  2001). Tibiotarsal OCD can be either unilateral or bilateral.

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Figure 8.9  The plantar tibiotarsal joint compartment seen looking laterally from a plantaromedial telescope portal. The distended joint capsule fills the image. Proximal is up and plantar is to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Preoperative radiographs are taken to establish a tentative diagnosis and to evaluate for bilateral disease. CT studies of the joint are highly recommended to establish a definitive diagnosis and to fully define the lesions. Bilateral arthroscopy is performed at the same time if bilateral lesions are found. Lesions on the plantar aspect of the medial ridge of the talus are approached with a plantaromedial telescope portal and a medial operative portal (Video 8.1) or through a plantaromedial mini-arthrotomy. Tibiotarsal OCD lesions occur most commonly on the plantar aspect of the medial ridge of the talus (Figure 8.11) but can also occur on the plantar aspect of the lateral ridge and uncommonly dorsally on either the medial or lateral ridges (Figure  8.12). Plantaromedial lesions are typically very large relative to the size of the joint and contain bone (Figure  8.13) leaving large defects in the medial ridge of the talus with removal (Figure 8.14). Significant villus synovial reaction is also typically present, especially with plantar lesions, adding to the difficulty of arthroscopic procedures (Figure 8.15). Stress applied over a bolster to open the medial aspect of the joint greatly facilitates examination of this small tight joint making operative procedures much easier and more effective. The lesion is visualized as shown in Figure 8.11 but many times lesions are not easy to define because of their size (Figure  8.15), irregular margins (Figure  8.16), fragmentation of the free osteocartilaginous lesion (Figure 8.17), or villus synovial reaction (Figure  8.18). Once identified the loose fragment is

Figure 8.10  The lateral head of the deep digital flexor tendon (tendon of the flexor hallucis longus) with the telescope directed proximally up the tendon sheath from a plantaromedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.11  A typical large plantar tibiotarsal OCD lesion on the medial ridge of the talus seen from a plantaromedial telescope portal. Proximal is to the upper right and plantar is to the bottom of the image. The free OCD fragment fills the right center of the image between the narrow portion of distal tibial articular surface seen on the far right and the exposed eburnated bone of the plantar medial ridge of the talus to the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

elevated if needed (Figure 8.19), grasped with rongeurs (Figures 8.20 and 8.21) or grasping forceps (Figure 8.22) and removed in one piece or multiple pieces as required. Minimal debridement of the defect is employed with

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.12  A small nondisplaced OCD lesion on the dorsal aspect of the medial ridge of the talus seen through a dorsolateral telescope portal. Proximal is up and dorsal or cranial is to the left. The medial ridge of the talus fills the lower right of the figure with the OCD lesion in the center, the dorsal or cranial margin of the distal tibial articular surface is to the upper right, and dorsal joint capsule with villus reaction is to the upper left. A large tibial osteophyte is seen as an irregular rounded white ridge at the top of the picture. The osteophyte was much larger than the OCD lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.13  The deep lateral margin of the large osteocartilaginous plantar tibiotarsal OCD lesion seen in Figure 8.11 showing the contained bone. Proximal is to the upper right and plantar is toward the bottom of the picture. A small area of distal tibial articular surface is to the right with the irregular talar ridge bone defect to the lower left. The free fragment is in the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.14  A typical large bone defect in the medial ridge of the talus following removal of a large plantar OCD osteocartilaginous fragment. The telescope is looking cranially from a plantaromedial portal with proximal up and medial to the right. The cranial margin of the defect fills the center of the picture with a narrow band of mildly frayed talar articular cartilage seen as a white layer surrounding the exposed bone. The tibial articular surface is visible curving around the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.15  A large plantar OCD osteocartilaginous fragment on the medial ridge of the talus that is difficult to define because of its size even with the tibiotarsal joint distracted over a bolus. The fragment fills the image with a small portion of exposed plantar talar ridge bone exposed at the lower right. Proximal is up and the telescope is looking cranially from a plantaromedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 8.16  A plantar OCD fragment that is difficult to visualize clearly because of irregular frayed and crumbling margins. The fragment originates from the medial ridge of the talus and fills the lower picture with loose cartilage seen across the top. Landmarks are not defined in the image. Proximal is up and the telescope is looking cranially from a plantaromedial portal. An instrument is visible in the background on the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.17  A free floating bone fragment filling the picture originating from a large plantar OCD lesion. This fragment interferes with accurate visualization of the primary lesion and landmarks are not defined. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

removal of loose fragments from the margin (Figure 8.23) and within the bed of the lesion (Figure 8.24) to produce a clean margin with a clean bed of exposed bone (Figure  8.14). Rongeurs, curettes, and graspers are used to remove larger loose cartilage and bone fragments with irrigation to remove fine debris. Since these plantaromedial OCD lesions are typically very large relative to the size of the joint and because removal

Figure 8.18  Villus synovial reaction in the plantar joint compartment secondary to a plantar OCD lesion that is obscuring visualization and is interfering with joint examination. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.19  Elevation of a plantar OCD osteocartilaginous fragment from the medial talar ridge using a 2.0mm hook probe to free it for removal. Proximal is up, medial is to the right, and the telescope is looking cranially from a plantaromedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

leaves a significant deep defect in the ridge of the talus, extensive debridement with curettage or with a power shaver is not done. Cartilage surrounding OCD lesions can be normal (Figure  8.25), and cartilage on the opposing joint surfaces can also be normal (Figure  8.26) or can have various degrees of cartilage damage from mild fraying (Figure 8.27), partial-thickness wear lesions (Figure 8.28), to full-thickness wear lesions with exposed bone and a smooth (Figure  8.29) or grooved (Figure  8.30) wear

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.20  Grasping a large plantar medial ridge OCD fragment using 2.5mm Stremple rongeurs. Proximal is to the upper right and medial is to the upper left. A small portion of tibial articular surface is visible to the far right, the OCD fragment fills the center of the image, and a portion of exposed talar bone is to the lower left. The telescope is looking cranially from a plantaromedial portal and the rongeurs are inserted through a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.21  Two-millimeter rongeurs positioned for grasping a small plantar medial talar ridge OCD fragment. Proximal is up and medial is to the right. The telescope is looking cranially from a plantaromedial portal with the instrument inserted through a medial portal. The talar ridge OCD defect is visible to the lower right, the plantar margin of the OCD fragment is in the center behind the tip of the forceps, and the tibial articular surface is visible to the upper left. A cartilage defect with exposed bone, Grade IV chondromalacia, covers most of the visible distal tibial articular surface. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.22  Removing a large loose plantar OCD osteochondral fragment from the medial ridge of the talus with 2.0mm arthroscopic grasping forceps inserted through a medial portal. Proximal is up and medial is to the right. The telescope is looking cranially from a plantaromedial portal. A small portion of tibial articular surface is seen in the upper left with villus synovial reaction to the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.23  A loose cartilage fragment from the dorsal or cranial margin of a plantar OCD lesion after removal of the primary fragment. The telescope is looking cranially from a plantaromedial portal with proximal up in the image. An area of grade IV chondromalacia of the distal tibial articular surface is visible to the upper left with the medial talar ridge OCD lesion bone defect to the lower right and the free fragment seen as the bright white material in the center of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 8.24  Multiple small loose bone and cartilage fragments in and surrounding the bed of a plantar medial talar ridge OCD lesion after removal of the primary fragment. This type of debris is removed with irrigation. Proximal is up and the telescope is looking cranially from a plantaromedial portal. The exposed bone of the OCD lesion fills the bottom of the image with a small portion of tibial articular surface visible across the top. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.25  Normal articular cartilage on the medial talar ridge cranial or dorsal to a plantar OCD lesion seen in the lower left of the image. The telescope is looking cranially from a plantaromedial portal. The material obscuring the bottom right of the image is OCD lesion debris that has not yet been removed. Proximal is up with normal tibial articular cartilage extending across the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.26  Normal cartilage on the opposing distal tibial articular surface overlying a plantar tibiotarsal OCD lesion. The free cartilage fragment had been removed prior to taking this picture. Proximal is up with the telescope looking cranially from a plantaromedial portal. The tibial articular cartilage fills the top of the figure with the OCD lesion at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.27  Minimally frayed cartilage, Grade I chondromalacia, on the opposing distal tibial articular surface overlying a plantar tibiotarsal OCD lesion. Proximal is up and the telescope is looking cranially from a plantaromedial portal with medial to the left. The tibial articular surface is seen extending obliquely across the top right of the image with the area of frayed cartilage at the center of the visible cartilage. The talar cartilage cranial or dorsal to the OCD lesion is seen filling the bottom of the picture with villus synovial reaction of the medial joint capsule to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.28  Partial thickness cartilage wear of the distal tibial articular surface, Grade II chondromalacia, opposing a plantar talar OCD lesion. Blisters are also seen in the tibial cartilage adjacent to the wear lesion. Proximal is to the upper left and plantar is to the lower left. Exposed bone of the OCD lesion is seen to the lower right with a rim of cartilage at its far margin. The tibial articular surface fills the left side of the image with blisters in the center of the exposed surface and the area of wear above the blisters. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.29  A large area of full thickness cartilage loss with smooth eburnated exposed bone, Grade V chondromalacia, on the distal tibial articular surface overlying a plantar talar OCD lesion. Proximal is up and the telescope is looking cranially from a plantaromedial portal. The tibia is seen across the top of the picture and irregular cartilage of the OCD lesion fragment fills the bottom with a strand of clotted blood on top of the cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.30  Full thickness cartilage loss from the talar and opposing distal tibial articular surfaces with a grooved wear pattern, glaciation, seen in the exposed bone. Proximal is to the upper left and plantar is to the lower left. The telescope is looking cranially from a plantaromedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.31  Smooth feathering of the margin of a full thickness wear lesion on the distal tibial articular surface. Proximal is to the upper right and the telescope is looking cranially from a plantaromedial portal. The tibial articular surface is to the right with exposed bone in the lower right, the feathered are of cartilage at the center right, and normal cartilage to the upper right. The talar ridge is to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

pattern. The margins of these wear lesions can be smooth and feathered (Figure 8.31), full thickness (Figure 8.32), or frayed (Figure 8.33). Dorsal OCD lesions of the talus are typically smaller (Figure  8.12) than plantar lesions and are approached

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Figure 8.32  Full thickness cartilage at the margin of exposed bone on the distal tibial articular surface over a plantar talar OCD lesion without the tapered appearance seen in the previous figure. The tibial articular surface is at the top and a plantar medial talar ridge OCD lesion fills the bottom of the image. Proximal is up and the telescope is looking cranially from a plantaromedial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.34  The osteophyte on the dorsal or cranial margin of the distal tibial articular surface, seen at the far left of the image, overlying a dorsal talar OCD lesion. The medial ridge of the talus fills the right side of the picture and the OCD lesion can be partially seen at the bottom of the image as a slight roughening of the cartilage. The telescope is looking medially from a dorsolateral portal with proximal up and dorsal or cranial to the left. The dorsal or cranial margin of the distal tibial articular surface is visible at the upper right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

through dorsal portals with loose fragment removal and defect debridement. The osteophytes formed over dorsal OCD lesions can be larger than the OCD lesion (Figure 8.34), and there is mild (Figure 8.35) to marked localized villus synovitis (Figure 8.36). The defect from removal of the OCD lesion is also seen in the previous image (Figure 8.36). In addition to the villus synovial reaction seen with plantar (Figure 8.18) and dorsal (Figures 8.35 and 8.36) talar OCD lesions, pannus is also seen in association with talar OCD lesions (Figure 8.37). Reattachment of large plantar talar OCD lesions using immobilization and stem cells injected into the joint presents an interesting possible alternative to traditional lesion removal especially in the elbow, stifle, and tibiotarsal joints where long-term results are not as good as we would like.

8.5.2  Intra-Articular Fracture Management Figure 8.33  Marked fraying of the distal tibial articular cartilage at the margin of a full thickness wear lesion in a tibiotarsal joint with a plantar talar OCD lesion. Proximal is up and the telescope is looking cranially from a plantaromedial portal. The tibial articular surface fills the upper right of the image with talar articular surface to the lower left. Chondromalacia is seen in the talar articular cartilage and villus synovial reaction is seen in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Evaluation and management of intra-articular fractures of the talus (Figure 8.38) and distal tibia (Figure 8.39) can be assisted with arthroscopy for diagnosis, to assess articular cartilage damage (Figure  8.40), to facilitate decision making for reconstruction options, for removal of small intra-articular fragments (Figure 8.41), and for improved visualization of the intra-articular fracture line during fracture reduction (Figure 8.42).

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.35  Mild localized villus synovial reaction in association with an osteophyte on the dorsal margin of the distal tibial articular surface overlying a small dorsal ridge OCD lesion. The telescope is looking laterally from a dorsomedial portal with proximal up and dorsal or cranial to the right. The dorsal or cranial tibial articular margin is seen across the top of the image, the dorsal portion of the lateral talar ridge is to the lower left, the osteophyte is the irregular bone to the right of center, and the villus synovial reaction is seen overlying the osteophyte. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.37  Pannus extending over the distal tibial articular surface in a joint with a plantar talar OCD lesion. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.38  A plantaromedial talar fracture with avulsion of ligaments from their talar attachments. Proximal is up and the ligaments fill the image obscuring visualization of other structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.5.3  Soft Tissue Injuries

Figure 8.36  Extensive villus synovial reaction seen filling the dorsal joint compartment of a tibiotarsal joint with a dorsal talar OCD lesion. The defect from removal of the OCD lesion is seen under, to the right of the area of villus synovial reaction. Proximal is up and cranial or dorsal is to the left with the telescope looking medially from a dorsolateral portal. The talus is seen to the right and a small portion of distal tibia is seen at the top of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Any and all of the soft tissue structures in and around the tibiotarsal joint and intratarsal joints can be injured. Arthroscopy provides a minimally invasive approach for diagnosis, assisting in selecting and planning open operative procedures, and during reconstruction.

8.5.4  Immune-Mediated Erosive Arthritis Arthroscopy is an effective method for joint examination and biopsy collection in cases of suspected immunemediated arthritis.

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Figure 8.39  Visualization of a fracture on the dorsal margin of the distal tibial articular surface seen through the tibiotarsal joint from a plantar telescope portal. Proximal is up on the image. The talar articular surface with minimally damage cartilage is seen across the bottom of the image. The distal tibial articular surface is seen in the upper right with the fracture line on the distal tibia is seen in the center of the image. The fracture fragment is not visible. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.40  Distal tibial articular cartilage damage secondary to the fracture seen in Figure 8.39. The tibial articular surface is seen extending from the right across the top to the upper left of the image with the talus in the lower left. Full thickness cartilage damage is present on the right half of the visible tibial articular surface with normal cartilage to the left. Proximal is up. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.41  The tibial fracture fragment in the dorsal joint compartment of the joint seen in Figure 8.39 and Figure 8.40. This fragment was removed with arthroscopy. The fracture fragment fills the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.42  A sagittal talar fracture that has been reduced using arthroscopic guidance prior to placement of a transverse screw. The talar articular surface fills the image and the reduced fracture line is seen as the vertical defect running vertically from the top to the bottom of the picture. Remember that magnification produced by the telescope and video system makes the gap look much bigger than it actually is. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.5  ­Diseases of the Tibiotarsal Joint Diagnosed and Managed with Arthroscop

Figure 8.43  Matching cartilage wear lesions, Grade V chondromalacia, on both tibiotarsal articular surfaces with matching bone grooves. Proximal is up with the tibial articular surface to the upper right and the talar articular surface to the lower left. There is no indication of etiology of the wear lesions in this joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.44  Matching smooth cartilage wear lesions on both distal tibial and talar articular surfaces. The margin of the talar wear lesions shows cartilage glaciation. Proximal is up and the tibial articular surface fills the top of the image with the talus at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

8.5.5  Osteoarthritis Cartilage wear lesions are seen in the tibiotarsal joint without a definable indication of primary etiology. These lesions appear similar to wear lesions seen in the elbow joint with “elbow dysplasia” and may be an indication of similar pathology in the tibiotarsal joint. These lesions are also similar to lesions seen with talar OCD so they may be a manifestation of old untreated OCD lesions. They may also be due to old untreated fractures, may be caused by an as yet undetermined etiology, or may be a combination of any or all of the above possibilities. There is suspicion that these are old untreated OCD lesions but there are no indications of defects in the talar ridges that would correspond to old OCD pathology. These lesions are most commonly seen as extensive matching lesions on both articular surfaces that have matching grooves worn into the bone (Figure 8.43) or can be smooth (Figure 8.44). Margins of the wear lesions can be feathered and smooth (Figure  8.43), with glaciation (Figure  8.44) as seen in elbow joint wear lesions or frayed and irregular (Figure 8.45). Indication of etiology is rarely seen in the presence of these wear lesion but occasionally an area of residual cartilage is seen in the center of the area of wear (Figure 8.46) suggesting an old OCD lesion. Arthroliths are seen in the tibiotarsal joint (Figure 8.47) typically without an obvious source or etiology. These free joint bodies can be removed arthroscopically (Figure 8.48). Aspects of the cartilage

Figure 8.45  Frayed and irregular cartilage margin of wear lesions on the articular surfaces in the tibiotarsal joint. Proximal is up with the tibia at the top and talus at the bottom. The transition from full thickness cartilage loss to normal cartilage has a feathered appearance. The left center of the image is filled with frayed strands of cartilage from another area of bone to cartilage transition. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

wear pattern and exposed bone in joints with arthroliths are similar to the previously described osteoarthritic joints without any defined etiology (Figure 8.49) except that osteocartilaginous fragments can cause wear grooves on the tibial articular surface (Figure 8.50).

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Figure 8.46  A residual area of cartilage in the center of a talar wear lesion suggestive of an OCD lesion. Proximal is up and exposed bone of the talus fills the bottom of the image with a small area of tibia in the upper background. The white area of irregular cartilage is in the center of the talar wear pattern. This can occur when there is a bone defect left by displacement of an OCD fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.47  An arthrolith in the tibiotarsal joint without an identifiable source or etiology. Proximal is up with medial to the right and the telescope is looking cranially from a plantaromedial portal. The bone fragment is in the center right with the talus to the lower left and the tibia in the background at the top. There is extensive cartilage loss in the area of the arthrolith but the damage also extends to an extensive are of joint surface beyond the area that could be damaged by the bone fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.48  The arthrolith in the previous figure was removed arthroscopically. This image is with the same telescope position and image orientation as in the previous image. This shows the indentation in the bone on the abaxial aspect of the medial talar ridge where the arthrolith was and the frayed soft tissue where it was attached. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 8.49  Cartilage wear lesions in a joint without an arthrolith showing exposed bone similar to the changes seen in joints without a defined etiology. Proximal is up with the distal tibial articular surface across the top and the talus filling the bottom of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

  ­Reference

Figure 8.50  Cartilage wear lesions in the same joint as the previous case with residual cartilage in the bone wear grooves. The difference in the presentation in this image compared to the previous image has not been explained. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

­References Cook, JL. & Tomlinson, JL. et al. (2001) Arthroscopic removal and curettage of osteochondrosis lesions on the lateral and medial trochlear ridges of the talus in two dogs. J. Am. Anim. Hosp. Assoc. 37:75–80. Freeman, LJ. (ed) (1999) Veterinary Endosurgery. Mosby, St Louis.

Miller, J. & Beale, B. (2008) Tibiotarsal arthroscopy. Applications and long-term outcome in dogs. Vet. Comp. Orthop. Traumatol. 21. 159–65. Rodriguez-Quiros, J. & Rovesti, GL. et al. (2014) Evaluation of a joint distractor to facilitate arthroscopy of the tibio-tarsal joint in dogs. J. Small Anim. Pract. 55, 213–8.

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9 Problems and Complications Significant complications are very uncommon with arthroscopy in small animals. Arthroscopy in over 2600 joints performed by the author has produced three cases of suspected nerve irritation. These three cases experienced excessive postoperative pain for approximately six weeks. None exhibited any functional nerve deficits. All three resolved completely with time. There were no detectable cases of joint contamination or septic arthritis caused by arthroscopy in this series of patients. One patient chewed out all the sutures from an arthroscopically assisted UAP removal to create an open joint with a resultant septic arthritis that resolved with joint irrigation and antibiotics. There is extensive literature on the complications of arthroscopy in people but much of this does not apply to our small animal patients. Many of the listed complications are related to thromboembolism, cosmetic deformities, and synovial fistulas. Nerve damage is a common complication and probably has the closest relationship to our patients but the comparisons do not fit. A comprehensive comparison of the complications in human and veterinary medicine is beyond the scope of this book.

9.1 ­Actual and Potential Complications of Arthroscopy 9.1.1  Failure to Enter the Joint Inability to establish telescope or operative portals prevents performing the procedure. This is a common complication for beginners and becomes much less common with experience. This really is not a complication but is simply part of the learning curve.

9.1.2  Articular Cartilage Damage This is common in early cases for the beginner and decreases with experience. Cartilage damage occurs with needle placement for the telescope portal as linear cuts (Figure 9.1) or as focal lesions (Figure 9.2) and during operative portal placement (Figure  9.3). Needles used for arthrocentesis and portal placement are easily burred when bone is contacted during placement (Figure  9.4) greatly increasing the potential for and severity of cartilage damage. Telescope trocar placement is another source of potential cartilage damage also producing linear cuts (Figure 9.5) or focal lesions with partial- (Figure  9.6) or full-thickness (Figure  9.7) injuries. Operative hand instruments can damage cartilage by applying excessive pressure to crush the cartilage (Figure 9.8) or removing cartilage by cutting or chewing. Power instruments such as the arthroscopy shaver have the potential to cause extensive cartilage damage very quickly at one location (Figure 9.9) or over an extensive area of the joint (Figure 9.10). Because of this, their use is recommended for experienced surgeons. Proper shaver blade positioning is critical to preventing cartilage damage with the cutting portion of the blade. The cutting portion of the blade must be visible whenever power is applied, and it is not directed toward any structure that is not planned for removal (Figure  9.11). Radiofrequency devices are also potential sources for cartilage damage (Figure 9.12) when not used properly. Most articular cartilage damage is of limited significance and is difficult to find without the magnification of the arthroscope. Minimizing articular cartilage damage is important but the small amount of cartilage damage seen with arthroscopy is much less than damage that occurs with an open arthrotomy. Articular cartilage

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

9.1  ­Actual and Potential Complications of Arthroscop

Figure 9.1  Linear cartilage damage in the shoulder joint caused by initial needle placement prior to telescope portal placement. The needle cut a full thickness transverse groove in the humeral head articular cartilage. Pink coloration in the base of the groove is exposed subchondral bone. The telescope is looking medially from a lateral portal with proximal up and cranial is to the left. The humeral head fills the bottom of the image with the glenoid articular surface across the top and the medial joint capsule is seen in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.2  Focal cartilage damage in the elbow joint caused by initial needle placement prior to telescope portal placement. This injury is irregular with multiple areas of cartilage penetration and loose flaps of variable thickness cartilage in both the humeral and ulnar cartilage. The telescope is looking laterally from a medial portal with proximal to the upper left and cranial to the lower left. The articular cartilage of the ulnar semilunar notch is seen curving around the lower right of the image with the medial surface of the lateral ridge of the humeral condyle filling the upper left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.3  A 20 gauge hypodermic needle placed to establish position for a craniomedial elbow operative portal causing cartilage damage. The tip of the needle cut a linear free flap of cartilage in the ulnar articular surface. The telescope is looking laterally from a medial portal with proximal to the upper left and cranial to the upper right. The ulnar articular surface of the semilunar notch fills the image with exposed bone in the bed of the cartilage cut at the bottom, the free cartilage curving up from the lower left, and the needle coming into the picture from the far left side. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.4  A burred needle created when bone was contacted during placement. Burred needles greatly increase the potential for cartilage damage and the severity of damage when it does occur. The image is of a shoulder joint with the telescope looking medially from a lateral portal, proximal or dorsal up, and caudal is to the left. The glenoid is seen in the top of the picture and the humeral head is at the bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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Figure 9.5  Linear cartilage damage in the glenoid articular surface in a shoulder joint caused by a telescope trocar during telescope portal placement. The groove is close to full thickness but bone is not visible in the lesion. The telescope is looking medially from a lateral portal with the glenoid filling the top of the figure, the humeral head at the bottom, and medial joint capsule is visible across the center in the background. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.6  Mild partial thickness focal ulnar cartilage damage caused by telescope trocar placement in an elbow joint. The telescope is looking laterally from a medial portal with humeral condyle to the upper left and ulnar semilunar notch articular cartilage filling the lower right of the image. A flap of free cartilage elevated by the trocar cannula is visible in the center of the picture with the cartilage defect below it at the lower right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.7  Full thickness focal ulnar cartilage damage produced during telescope trocar placement in the elbow joint. The telescope is looking laterally from a medial portal with proximal up to the left and cranial down to the left. The undamaged humeral condyle is to the upper left with the damaged ulnar cartilage to the lower right. Multiple free cartilage fragments have been created, a large full thickness defect is present in the lower left of the image, and an area of partial thickness injury extends to the right. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.8  Crushed cartilage on the humoral condyle caused by excessive pressure with an operative hand instrument. The telescope is looking craniolaterally from a medial portal with the medial ridge of the humeral condyle filling the top of the image, the articular surface of the medial coronoid process in the lower right background, the radial head to the left, and the radio-ulnar articulation as a fine curving line extending obliquely across the lower left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

9.1  ­Actual and Potential Complications of Arthroscop

Figure 9.9  Inappropriate focal full thickness cartilage damage on the humoral head caused with a power shaver. The telescope is looking medially from a lateral portal with proximal to the right in the image, the humeral head to the left, the glenoid articular surface to the right, the cartilage defect with exposed bone in the center, and a loose cartilage fragment displaced by the shaver blade. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.10  Widespread cartilage damage on the humeral head caused with a power shaver by accidental activation of the shaver prior to proper positioning and without adequate control of the shaver handpiece. The telescope is looking medially from a lateral portal with proximal up and cranial to the left. The humeral head with multiple semilunar cartilage cuts is to the lower left with the undamaged glenoid articular cartilage to the upper right. The shaver burr walked across the cartilage surface producing multiple deep cartilage cuts and displaced multiple free cartilage fragments. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.11  Improper placement of a shaver blade with the cutting surface placed against normal cartilage that is not planned for removal. This image is in the stifle joint and the blade is positioned against normal femoral condyle cartilage in the upper left. The tissue for removal is the cut end of the meniscus that is visible in the lower left of the image. The blade was repositioned prior to activation. The cutting blade of the shaver is visible as a verry narrow line of metal to the left of the fixed outer sheath of the blade seen as a flat surface in the upper center and the back side of the fixed outer sheath is seen in the upper right of the picture. Proximal is up on the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.12  Damage to the medial aspect of the lateral femoral condyle cartilage caused by a radiofrequency (VAPR) handpiece used to complete removal of the origin of the cranial cruciate ligament. Proximal is up with lateral to the right and the telescope is looking caudolaterally from a craniomedial portal. The vertical white structure on the left is the caudal cruciate ligament and the medial aspect of the lateral femoral condyle is to the right. The origin of the cranial cruciate ligament is the flat area of soft tissue in the upper center of the image between the caudal cruciate and the medial articular cartilage of the lateral femoral condyle. The dark areas on the remnant of the cranial cruciate ligament is thermal change associated with the vaporization process and the dark areas on the articular cartilage are undesirable thermal damage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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damage from arthroscopy in dogs has been documented but its significance has not been determined (Klein and Kurze 1986; Rogatko et al. 2018).

9.1.3  Soft Tissue Damage Iatrogenic intra-articular soft tissue injures are another complication of arthroscopy. Damage to medial shoulder soft tissue structures is seen with excessive penetration during placement of the telescope trocar at the lateral portal site with minor (Figure  9.13) or major (Figure 9.14) injuries to the medial glenohumeral ligament or injury to the subscapularis tendon (Figure 9.15). Medial collateral ligament injuries are seen in the elbow joint caused by operative portal needle placement (Figure  9.16), trauma during medial coronoid process removal with a shaver (Figure 9.17), and disruption of the medial collateral ligament insertion with aggressive subtotal coronoidectomy (Figure 9.18). Avulsion of the origin or insertion and rupture of the medial collateral ligament of the elbow can be caused by excessive internal rotational force for elbow positioning during arthroscopy (Figure 9.19). The significance of these soft tissue injuries has not been determined or the extent of

Figure 9.13  A partial thickness minor penetrating injury to the medial glenohumeral ligament caused by over penetration of the telescope trocar at the lateral portal site. The injury is seen as a shallow oval indentation just above the free margin of the ligament in the center of the image. The telescope is looking medially from a lateral portal with dorsal up and cranial to the left. The humeral head is visible in the lower right with the medial glenohumeral ligament arching across the top with the vertical fibers of the subscapularis tendon between the other two structures. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.14  A full thickness penetrating injury of the medial glenohumeral ligament due to excessive penetration of the telescope trocar from the lateral portal site. The injury is seen as a dark slit in the left end of the ligament just below its upper margin. The telescope is looking medially from a lateral portal with proximal up on the image and cranial to the left. The humeral head is at the bottom, the glenoid at the top and the glenohumeral ligament is traversing horizontally across the middle of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.15  A penetrating injury of the subscapularis tendon caused by over penetration of the telescope trocar during placement at the lateral portal site. The injury is seen as a liner dark area at the top center of the tendon adjacent to where it disappears under the glenohumeral ligament. The telescope is looking medially from a lateral portal with dorsal up and cranial to the right. A small portion of humeral head is visible at the bottom of the picture with the medial margin of the glenoid to the upper left and a narrow band of medial glenohumeral ligament below and parallel to the glenoid margin. The subscapularis tendon is the wide band of tissue with vertical fibers extending across the middle of the image between the humeral head and the glenohumeral ligament. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

9.1  ­Actual and Potential Complications of Arthroscop

Figure 9.16  Partial transection of the medial collateral ligament of the elbow by the 20 gauge hypodermic needle used for establishing location of the operative portal. The telescope is looking cranially from a medial portal with proximal up on the image and craniomedial to the right. The medial coronoid process fills the bottom of the picture with the radial head to the left and the medial ridge of the humeral condyle across the top. The medial collateral ligament is the vertical tubular structure being cut by the needle. A small area of villus synovial reaction is seen in the center. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.17  Extensive damage to the medial collateral ligament of the elbow caused by the power shaver blade during removal of the medial coronoid process. The telescope is looking cranially from a medial portal with proximal up and craniomedial to the right. The damaged ligament is the frayed tissue filling most of the image and the margin of the partially removed medial coronoid process is visible at the very bottom. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.18  Transection of the medial collateral ligament insertion during aggressive subtotal coronoidectomy with a power shaver. The telescope is looking cranially from a medial portal and the shaver burr is inserted through a craniomedial portal. Proximal is up and craniomedial is to the right. The resected surface of the medial coronoid process is at the bottom of the image with the transected insertion of the medial collateral ligament seen as the frayed tissue to the left. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.19  Partial rupture or avulsion of the medial collateral ligament of the elbow joint secondary to excessive rotational force used for joint positioning during arthroscopy. The telescope is looking cranially from a medial portal with up proximal and medial to the left. The damaged ligament is seen as the vertical tubular structure in the center of the image with a band of tense fibers on the left side and loose fibers on the right. The resection surface of the medial coronoid process is at the bottom and a palpation probe is seen on the left entering through a craniomedial operative portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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these injuries needed to be clinically significant. Arthroscopy is also much less traumatic to intra-articular and peri-articular tissues than an open arthrotomy.

9.1.4  Bone Fragment Displacement Free floating cartilage or bone fragments that migrate into inaccessible joint spaces potentially cause complications following arthroscopy. These free fragments can be present at the time arthroscopy is initiated as part of the underlying pathology or created by the operative procedure. Shoulder OCD lesions are a common source of naturally occurring free floating fragments that can migrate into the medial joint space (Figure 9.20) and of iatrogenic free cartilage fragments (Figure 9.21). Leaving a small point of attachment in the craniomedial portion of OCD lesions when they are elevated from their bed until the partially freed cartilage is grasped for removal reduces the incidence of this problem. Free floating fragments in the shoulder also migrate medial to the glenohumeral ligament between this ligament and the

Figure 9.21  An free flap of OCD cartilage in the medial joint space lost during removal of a humeral head lesion. Complete separation of the OCD cartilage flap before grasping the fragment can cause this problem. The free flap is seen as the irregular material extending above the medial margin of the humeral head visible at the very bottom of the image. A curved mosquito hemostat is positioned from a caudolateral portal extending into the top of the image and medial joint capsule is seen deep to the hemostat and cartilage fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

subscapularis tendon (Figure 9.22) and can completely disappear into this space. Manipulation of the joint through multiple axes facilitates dislodging fragments in this location so that they can be removed. Irrigation through the telescope cannula has a tendency to move these floaters making capture difficult. Fragments are occasionally lost into the joint capsule extension of the biceps preventing removal through the standard shoulder portals. Placement of a craniolateral portal for the telescope and placing an operative portal over the fragment (Figure 3.5) can be used to access this area.

Figure 9.20  A naturally occurring free floating cartilage fragment in the craniomedial area of the shoulder joint origination from an OCD lesion. Removal is required to minimize postoperative complications. The telescope is looking craniomedially from a lateral portal with cranial to the left and proximal up. The humeral head is in the lower right with the articular surface of the supraglenoid tubercle in the upper left and the medial glenohumeral ligament in the upper right. A small area of synovial reaction around the origin of the bicipital tendon is visible at the far left and subscapularis tendon is seen to the right of the loose cartilage. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

9.1.5  Operative Debris Debris produced by arthroscopic operative procedures is common, especially in the elbow, and is removed prior to concluding the procedure. Large debris, welldefined small bone or cartilage fragments (Figure 9.23) are removed with grasping instruments or small rongeurs. Fragments in this location can become wedged in place or be too far laterally to grab with rongeurs or forceps and need to be extracted using the 1.0-mm graduated probe, 2.0-mm graduated probe, or the 70°

9.1  ­Actual and Potential Complications of Arthroscop

Figure 9.22  A naturally occurring free floating cartilage fragment originating from a shoulder OCD lesion that has migrated into the space between the medial glenohumeral ligament and the subscapularis tendon. The fragment is seen as an irregular white structure with short fingerlike projections protruding from behind the bottom of the glenohumeral ligament at the far left of the image. The telescope is looking medially from a lateral portal with proximal up and cranial to the left. The glenohumeral ligament is at the top of the image and its ventral margin is angled from the upper left down to the right. The subscapularis tendon runs across the center of the image with its fibers perpendicular to the glenohumeral ligament and it is behind the glenohumeral ligament. A small portion of humeral head is visible at the bottom of the image and narrow sliver of supraglenoid tubercle is seen at the upper left. Villus synovial reaction is present in this joint with the most obvious on the lateral surface of the glenohumeral ligament where it is in front of the cartilage fragment. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

microfracture chisel. Smaller debris (Figure  9.24) is removed with instruments or with irrigation. As much debris, as possible is removed but it is not always feasible to completely remove very small debris in difficult to access areas of the joints (Figure 9.25). The amount or size of debris that is safe to leave in joints has not been determined so it is best to remove all reasonably accessible debris.

9.1.6  Red Out Intra-articular bleeding that obscures the visual field (Figure 9.26) is termed “Red-Out.” In many cases when this occurs, increased irrigation, either flow or pressure, will clear the field. When the field cannot be cleared, the procedure must be discontinued by conversion to an

Figure 9.23  A single small bone fragment wedged between the radial head and humeral condyle. This fragment was removed by manipulation with the 70-degree microfracture chisel to displace it medially into a space where it could be grasped and removed. The telescope is looking craniolaterally from a medial portal with proximal to the upper left on the image and cranial to the upper right. The lateral ridge of the humeral condyle fills the upper left of the picture with the radial head to the lower right. A small segment of ulnar articular surface is visible at the lower right margin of the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.24  Multiple debris fragments are visible in the lateral joint space of the elbow joint as variable sized irregular white material against similar colored joint capsule. This debris was removed with irrigation and suction during manipulation of the joint. The telescope is looking laterally between the lateral ridge of the humeral condyle to the upper right and the semilunar notch of the ulna to the lower left. The lateral coronoid process of the ulna and the caudal margin radial head are seen in the background to the left and the lateral joint capsule is seen in the background to the right. A small area of cartilage damage that was caused by initial needle placement is present on the humeral condyle. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

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open surgery or delay to another day. Red Out to the extent that the procedure has to be discontinued is a rare occurrence.

9.1.7  Peri-articular Fluid Accumulation Extravasation of fluid around joints interferes with arthroscopy by collapsing the joint capsule and obscuring visualization. This fluid is readily reabsorbed and does not cause a problem for the patient.

9.1.8  Infection

Figure 9.25  A small quantity of very fine debris trapped in a blood clot in the lateral joint space of an elbow joint seen with the telescope looking laterally from a medial portal. This blood clot and debris was not removed. The lateral humeral condyle fills the top of the image with the caudal margin of the radial head in the lower left and the lateral coronoid process in the lower right. The blood clot with debris is seen in the background behind the radial head and the junction of the radial head and lateral coronoid process of the ulna. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.26  A “red out” defined as an obscured visual field during arthroscopy caused by intra-articular bleeding. This can many times be cleared by manipulation of irrigation parameters. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Iatrogenic infection is reported as a complication of arthroscopy in the human and veterinary literature (Ridge 2011) but has not occurred with arthroscopy of over 2600 joints performed by the author. The treatment for septic arthritis is irrigation of the joint, and since arthroscopy is performed with continuous irrigation, there is little risk of joint contamination (Fearnside and Preston 2002; Luther et al. 2005). Inadequately cleaned instruments (Figure 9.27), even when autoclaved, are a potential source for infection. Magnification of the image by the telescope and video system allows dirty instruments to be identified when this is not seen during cleaning or preoperatively.

Figure 9.27  Adhered residual debris seen in the cup of a curette that was not properly cleaned but is seen during arthroscopy due to the magnification caused by the video system. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

9.2  ­Instrument Damag

9.1.9  Vascular Injury Vascular injury is also reported in the human literature as a complication of arthroscopy. Damage to small subcutaneous vessels has occurred infrequently in small animal patients but there have not been any cases of significant vessel damage or blood loss. Interference with visualization can occur when blood enters the joint from injured peri-articular vessels. This bleeding is managed with increased irrigation flow or pressure.

9.1.10  Nerve Injury Damage to nerves is the most serious complication of arthroscopy in human medicine. Nerves that are at risk during canine arthroscopy are discussed with each joint following the portal sites and portal placement text.

9.2 ­Instrument Damage 9.2.1  Intra-articular Instrument Breakage

Figure 9.29  One side of the jaw of a 2.0mm arthroscopy grasping forceps that broke during removal of a tibiotarsal joint OCD fragment and lodged in the articulation between two tarsal bones. Removal was successful with arthroscopy but required significant time. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Breakage of instruments in joints during operative procedures is an uncommon event. Any and all instruments placed into joints can break but the most common are power shaver burrs (Figure 9.28), small (2 mm) grasping forceps (Figure  9.29), and no. 11 Bard-Parker scalpel blades. Other than adding time to the procedure instrument breakage does not, in most cases, cause problems or

Figure 9.30  Removing a broken power shaver burr fragment from the elbow using a curved mosquito hemostat. The hemostat is seen at the top of the image with the shaver burr fragment in the background. The medial surface of the radial head is on the left and residual bone of the medial coronoid process is at the bottom with the telescope looking cranially from a medial portal. Source: Timothy C. McCarthy. © John Wiley & Sons Inc. Figure 9.28  A 2.5mm power shaver burr broken off in the elbow joint of a dog during subtotal medial coronoid process removal. A curved mosquito hemostat was used to remove this instrument fragment from the joint. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

complications for the patient. Most broken instrument fragments are easily located and removed (Figure 9.30). If the broken piece of instrument cannot be found or removed with arthroscopy, conversion to an open procedure

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is required adding time and trauma to the surgery. Inability to find or remove the instrument fragment with open surgery leaves a foreign body in the joint that is a significant complication. All broken instrument fragments have been removed successfully with arthroscopy in the author’s experience. One case required a prolonged time period to remove the broken instrument fragment (Figure  9.29). Most instruments when they break in joints break cleanly but rarely they shatter producing many small metal fragments (Figure 9.31).

9.2.2  Telescope Breakage Telescope damage during arthroscopy is a problem that, like instrument breakage, effects the surgeon but not the patient. A dirty distal telescope lens (Figure  9.32) interferes with performing the procedure by decreasing image quality. A properly cleaned distal lens is critical to performing proper arthroscopy. If poor image quality is noted during arthroscopy, cleaning is performed intraoperatively. When this is a consistent problem, cleaning the lens with the telescope attached to the video camera system aids in proper cleaning. The camera is focused all the way to its closest point which is at the lens of the telescope, and the distal lens is cleaned while observing the image on the video screen. Magnification and lighting produced by the camera system allow effective complete cleaning.

Figure 9.32  A dirty telescope lens that obscures the visual field. This image is captured with the video camera focused to its closest point, right at the lens, allowing a magnified image of the lens surface. If a dirty lens is a consistent finding during arthroscopy it is recommended to clean the lens with telescope on the camera with focus on the lens surface as shown here. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Figure 9.33  Bending telescopes produces a “halo” or a black area if infringement on one side of the image. When this halo is seen, it indicates that the telescope is being damaged by excessive bending force. Source: Timothy C. McCarthy. © John Wiley & Sons Inc. Figure 9.31  A broken 3.5mm power shaver burr that shattered creating many small metal fragments in the joint. The large fragment was easily removed with a curved mosquito hemostat. It was difficult and time consuming to clean all the small fragments from the joint but this was accomplished with irrigation and various grasping instruments. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

Bending pressure applied during telescope manipulation when performing arthroscopy will break the arthroscope. Early warning that the telescope is being bent is appearance of a black “halo” on one side of the image (Figure 9.33). Correcting the force being applied

9.3  ­Contraindication

Figure 9.34  Damage to the distal lens of a telescope caused by contact with a rotating power shaver blade. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

to the telescope when this is seen will prevent damage to the telescope. Continued application of force will break the telescope. Damage to the distal lens of the telescope can be caused by contact with instruments in the joint while performing operative procedures. The lens can be shattered when pressure is applied toward the telescope with a hand instrument such as a curette when attempting to pry a fixed medial coronoid process fragment off of the bone and the instrument slips or the bone breaks off quickly. The most common cause of distal lens damage is inappropriate manipulation of power shaver blades. Contact of a revolving shaver blade with the distal lens of the telescope destroys the image instantly (Figure 9.34) requiring telescope repair or replacement. For this reason and to prevent joint damage, power shavers must be used very carefully and preferably only by experienced surgeons. Another helpful tip to prevent arthroscope damage is to apply shaver blade rotation in the direction that pulls the tip of the blade away from the telescope. With use, telescopes can develop a leak at the distal lens. Liquid getting under the lens can totally fog the image or in some cases a pocket of liquid is visible in one part of the lens (Figure 9.35). When this occurs, telescope repair or replacement is required. Loss of image clarity can also occur if liquid gets between the proximal telescope lens and the camera lens. When there is sudden loss of image clarity, this is an area to check as it is an easy intra-operative fix.

Figure 9.35  A visible leak of liquid under the distal lens of an arthroscope seen as an irregular defect in the image. Source: Timothy C. McCarthy. © John Wiley & Sons Inc.

9.3 ­Contraindications There are no defined contraindications for arthroscopy in small animal practice.

9.3.1  Patient Size Small patients? This has been a defined and commonly mentioned contraindication for performing arthroscopy. The size of patient that can be examined with arthroscopy is only limited by instrumentation and our ability. Arthroscopy has been successfully performed in the hip and stifle of dogs as small as seven pounds, in the shoulder, elbow, and stifle of cats, and the stifle of rabbits.

9.3.2  Septic Arthritis Joint sepsis? Irrigation is a recommended treatment for septic arthritis and extensive irrigation is done when arthroscopy is performed. Septic arthritis has not been seen following arthroscopy in the author’s experience.

9.3.3  Anesthesia Risk All the standard concerns for anesthesia exist as with any surgical procedure but there are no specific anesthetic contraindications for arthroscopy.

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­References Fearnside, SM. & Preston, CA. (2002) Arthroscopic management of septic polyarthritis in a dog. Aust. Vet. J. 80, 681–3. Klein, W, & Kurze, V. (1986) Arthroscopic arthropathy: iatrogenic arthroscopic joint lesions in animals. Arthroscopy 2, 163–8. Luther, JF. & Cook, JL. et al. (2005) Arthroscopic exploration and biopsy for diagnosis of septic arthritis and osteomyelitis of the coxofemoral joint in a dog. Vet. Comp. Orthop. Traumatol. 18, 47–51.

Ridge, PA. (2011) A retrospective study of the rate of postoperative septic arthritis following 353 elective arthroscopies. J. Small Anim. Pract. 52, 200–2. Rogatko, CP. & Warnock, JJ. et al. (2018) Comparison of iatrogenic articular cartilage injury in canine stifle arthroscopy versus medial parapatellar miniarthrotomy in a cadaveric model. Vet. Surg. 47 (S1), O6–14.

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Index Page locators in bold indicate tables. Page locators in italics indicate figures. This index uses letter‐by‐letter alphabetization.

a

abduction instability  36 acetabular fossa  194–196, 198–201 acetabulum  193, 194, 195, 196–201 adipose tissue  44, 47 anconeal process  116–118, 117–120, 137, 139, 140–142, 159–163, 164 see also ununited anconeal process anesthesia  23 anesthesia risk  303 antebrachium  28, 113–114, 115, 160 arthrocentesis  31, 31 arthroliths elbow joint  108, 125, 146 hip joint  202, 203 shoulder joint  40, 50, 55–58, 59, 60, 64, 72, 72–73 stifle joint  274 tibiotarsal joint  289, 290 arthroscopy instruments  3–5, 4, 4 aseptic necrosis of femoral head  206, 206 avascular nodular roughening  224 avascular tissue elbow joint  152–153, 173, 175 shoulder joint  65–66, 70 stifle joint  221, 224–225, 246–247, 251 axillary nerve  40–41

b

bicipital extension of the joint capsule, shoulder joint  44, 50, 63 bicipital groove  42, 42–44

bicipital tendon examination protocol and normal anatomy  41–44, 42–44, 46–47, 59, 62–63 injuries  73–81, 74–81 biopsy elbow joint  181–182, 182 hip joint  206 radiocarpal joint  187, 190 shoulder joint  100–102, 103 stifle joint  270, 273 tibiotarsal joint  276, 287 blister‐like lesions elbow joint  130–131, 131, 133, 167, 167–171 shoulder joint  48, 51, 54, 105 stifle joint  228–229, 235–236, 238 tibiotarsal joint  285 bone fragment displacement elbow joint  149, 151, 153, 155, 159, 162, 172 173, 180 shoulder joint  298, 298–299 bucket handle tears of the meniscus  207, 243–244, 246–250, 250–252, 253–255

c

cannulas elbow joint  161, 163, 166, 167, 175, 180 instrumentation and equipment  6–8, 7–8, 7–8 shoulder joint  38–39 stifle joint  211–214, 212, 215, 233–234, 251, 254, 262

Veterinary Arthroscopy for the Small Animal Practitioner, First Edition. Timothy C. McCarthy. © 2021 John Wiley & Sons, Inc. Published 2021 by John Wiley & Sons, Inc. Companion website: www.wiley.com/go/mccarthy/arthroscopy

surgical technique and procedure  32–34, 32–33 cartilage wear lesions elbow joint  124, 135–136, 141–145, 147, 155–156 hip joint  196, 197–198 tibiotarsal joint  285, 289, 289–291 caudal articular surface, elbow joint  119 caudal cruciate ligament  207–208, 216, 217–218, 221, 227–228, 230, 235, 242, 244–245, 251–252, 258, 259 caudal tibial ligament of the medial meniscus  209, 216, 218, 252, 257–258 chondromalacia elbow joint  112, 124–149, 127–139, 154–158, 157, 171–172, 171–173, 181–183 hip joint  196–198 shoulder joint  48–59, 49–56, 53, 60–64, 75, 97–98, 102–104, 102–105 stifle joint  225, 228–238, 234–241, 261, 263, 270–273, 273 tibiotarsal joint  283–286 computed tomography (CT)  1–2 elbow joint  108, 123, 127, 144–145, 158, 164 shoulder joint  36, 47, 73–77, 82 cranial–caudal drawer instability, shoulder joint  36 cranial cruciate ligament  207–210, 208, 213, 213, 216, 217, 219, 221–258, 221–259

306

Index

cranial joint compartment, elbow joint  146, 159–161, 159–162 craniomedial flexor muscles, elbow joint  113 crepitus elbow joint  108, 176 hip joint  192 radiocarpal joint  187 shoulder joint  36 stifle joint  207 tibiotarsal joint  276 CT see computed tomography curettage elbow joint  147, 148, 150, 150–151, 157–159, 162–163, 165–166, 166, 172–174, 175–176 instrumentation and equipment  8, 10 shoulder joint  64–65, 68–70

d

degenerative joint disease (DJD) elbow joint  180 radiocarpal joint  187 stifle joint  208–210, 270–273 digital extensor tendon radiocarpal joint  188 stifle joint  216–219, 219–220, 224, 229, 268, 269 discoid meniscus  273, 273 DJD see degenerative joint disease dorsal labrum, hip joint  195, 200, 200 double pelvic osteotomy (DPO)  192 drawer instability, stifle joint  207 dysplasia elbow joint  108, 122–167, 124–167 hip joint  192, 196–201, 196–202

e

eburnated bone  141–143, 143–144 egress cannulas  8, 8, 8 egress portals elbow joint  113 hip joint  192–193, 193 radiocarpal joint  187 shoulder joint  40 stifle joint  211–213, 211–212 tibiotarsal joint  277, 278

elbow joint  108–186 arthroscopy‐assisted intra‐articular fracture repair  180–181, 181–182 biopsy of intra‐articular neoplasia  181–182, 182 cartilage wear lesions  124, 135–136, 141–145, 147, 155–156 chondromalacia  112, 124–149, 127–139, 154–158, 157, 171–172, 171–173, 181–183 degenerative joint disease  180 dysplasia  108, 122–167, 124–167 egress portals  113 examination protocol and normal anatomy  114–121, 114–122 immune‐mediated erosive arthritis  182, 182 incomplete ossification of the humeral condyle  182–183, 183 indications for arthroscopy  108 medial coronoid process disease  108–109, 111, 122, 142–146, 159, 165, 167, 169–171, 171–173, 176, 177 medial enthesiopathy  183–184, 183 nerves of concern  113 operative portals  111–113, 112 osteochondritis dissecans  108–112, 122–123, 167–175, 167–177 osteophytes  108, 111–113, 159–164, 160–165 patient preparation, positioning, and operating room setup  25, 26–28, 28, 108–109 portal sites and placement  109–113, 109–112 telescope portals  109–111, 110–111 ununited anconeal process  108–109, 113, 176–180, 178–180 electrocautery elbow joint  133 instrumentation  14–15, 15 problems and complications  292, 295 shoulder joint  78–79, 79–81, 93–94 stifle joint  221, 221, 246–257, 250–252, 256–257, 269, 271

erosions elbow joint  124, 131–138, 133–134, 138, 140 hip joint  197, 197 stifle joint  229, 237–239 see also immune‐mediated erosive arthritis

f

fascial strip implants  264, 265 femoral condyle  215–219, 217–221, 224, 226, 227–238, 228–236, 239–273, 258–262 femoral head  193–201, 194–206, 206 femoral trochlea  227 fiberoptic light guide  19–20, 20 Fiber Wire stabilization  264, 266–267 fibrillated cartilage elbow joint  130, 131, 133–134, 134–137, 140–142, 145 hip joint  196, 196–197 shoulder joint  49, 53, 56, 62 stifle joint  229, 236–239, 237, 241, 262, 263 fibrin  55, 58, 102 fibrosis elbow joint  145, 146–147 shoulder joint  59, 64, 89–90, 92–93, 105 fluids and electrolytes  31–32, 32 fractures elbow joint  171, 172, 174, 180–181, 181–182 hip joint  192, 195, 200–201, 200, 205–206, 205–206 radiocarpal joint  189–190, 189–191 shoulder joint  100–101, 101–102 stifle joint  266, 268 tibiotarsal joint  286, 287–288 free‐floating cartilage chips  50, 56–57

g

ghost villi shoulder joint  50, 61–62, 76, 84, 86–87, 89, 92–93, 96 stifle joint  221, 222, 225–226, 232, 264, 266–267 glaciation  129, 135, 141, 142–143

Index

glenoid articular surface examination protocol and normal anatomy  41, 41–42, 43–45, 45–46 glenoid cartilage defects  102–103, 103–104 shoulder joint injuries  89–90 see also ununited caudal glenoid ossification center Gore‐Tex prostheses  264, 266 granulation tissue, hip joint  203 gravity flow systems  16, 16 gunshot fractures elbow joint  181–2 shoulder joint  100–101, 101–102

h

hand instruments  8–11, 9–11, 11 hematomas  242, 244, 268 hip joint  192–206 arthroliths  202, 203 arthroscopy‐assisted intra‐articular fracture repair  205–206, 205–206 aseptic necrosis of femoral head  206, 206 biopsy of intra‐articular neoplasia  206, 206 chondromalacia  196–198 dysplasia  192, 196–201, 196–202 examination protocol and normal anatomy  193–195, 194–196 indications for arthroscopy  192 nerves of concern  193 osteophytes  198–201, 198–199, 201–202, 206 patient preparation, positioning, and operating room setup  29, 29, 192 portal sites and placement  192, 193 soft tissue injuries  203–204, 203–204 subluxation injury  199–200, 199, 203–204, 203–204 triple/double pelvic osteotomy  192 histiocytic sarcoma  272 humeral condyle articular surface chondromalacia/wear lesions elbow dysplasia  122–124, 124–167, 155–157 examination protocol and normal anatomy  114–121, 114–122

incomplete ossification of the humeral condyle  182–183, 183 osteochondritis dissecans  167–171, 167–176 humeral head articular surface osteochondritis dissecans  47–48, 47–48, 56 shoulder joint  41, 41, 45, 47–48, 47–48, 56 humeral trochlea  118, 119, 133–134, 140 hyperemia elbow joint  130, 137, 164, 169, 172–174, 180 shoulder joint  62, 67, 84, 86, 89, 92, 102 stifle joint  250, 254 hyperextension pain, shoulder joint  36

i

iatrogenic infection  300, 300 immune‐mediated erosive arthritis elbow joint  182, 182 radiocarpal joint  190 tibiotarsal joint  287 incomplete ossification of the humeral condyle (IOHC)  182–183, 183 infection  300, 300 infraspinatus muscle contracture  104–105, 105–106 instability of the shoulder  36 instrumentation and equipment  1–22 advantages and disadvantages  1 arthroscopes  3–5, 4, 4 hand instruments  8–11, 9–11, 11 indications for arthroscopy  1–2, 2 instrument damage  301–303, 301–303 introduction  1–3 irrigation fluid and management systems  15–17, 16–17 light source  19–20, 20 operative procedures  2–3, 3 power instruments  12–15, 12–15, 12 sheaths and cannulas  5–8, 6–8, 6–8

video system tower  17–20, 17–20, 18 see also microfracture chisels; power shavers intercondyloid fossa  219, 222, 227, 235, 241–242, 245–247, 250–251, 253, 256 intra‐articular fat, elbow joint  112, 121, 121 intra‐articular fluid density  208, 209 intra‐articular fracture repair elbow joint  180–181, 181–182 hip joint  205–206, 205–206 shoulder joint  100–101, 101–102 tibiotarsal joint  286, 287–288 intra‐articular instrument breakage  301–302, 301–302 intra‐articular irrigation fluid pressure  173 intra‐articular neoplasia elbow joint  181–182, 182 hip joint  206, 206 shoulder joint  100–102, 103 stifle joint  269–270, 273 IOHC see incomplete ossification of the humeral condyle irrigation fluid and management systems  15–17, 16–17

j

joint capsule elbow joint  110–113, 115, 118–121, 131–132, 139, 142, 146, 150, 160–163, 167–168 hip joint  193–195, 194–197, 199–205, 199–206 problems and complications  293–294, 298, 298–299, 300 radiocarpal joint  188, 190 shoulder joint  38–47, 39–40, 42–61, 59–60, 63–71, 73–75, 78–81, 80–81, 83–93, 85–90 stifle joint  211, 212, 213–215, 214–216, 219–224, 226, 229, 231–233, 250, 267, 270–271 tibiotarsal joint  276–278, 279–281, 284

l

lactated Ringer’s solution  15–16, 31–32, 32 lateral cartilaginous labrum, shoulder joint  46

307

308

Index

lateral collateral ligament elbow joint  110 shoulder joint  44, 47, 85 lateral coronoid process  111–113, 114–116, 116, 137, 139, 139–142, 164–165, 165–166 lateral labrum avulsion, shoulder joint  75–76, 81, 87–88, 88 LDE see long digital extensor long digital extensor (LDE) tendon, stifle joint  216–219, 219–220, 224, 229, 268, 269 loose marginal cartilage, shoulder joint  64, 68–70

m

magnetic resonance imaging (MRI)  1–2 elbow joint  108 shoulder joint  36, 46, 73–76, 82, 85 MCPD see medial coronoid process disease MCPP see medial coronoid process pathology mechanical arthroscopy fluid pumps  16–17, 17 medial collateral ligament, elbow joint  109, 111–114, 112, 114, 117, 119, 120, 122 medial coronoid process elbow dysplasia  122–167, 122–167 examination protocol and normal anatomy  114–121, 114–122 patient preparation, positioning, and operating room setup  26–28, 26, 108–109 problems and complications  294, 296, 297 medial coronoid process disease (MCPD)  1–2, 108–109, 111, 122, 142–146, 159, 165, 167, 169–171, 171–173, 176, 177 medial coronoid process pathology (MCPP)  26, 28, 113, 122, 131, 147, 164, 168, 169, 177 medial enthesiopathy  183–184, 183 medial glenohumeral ligament examination protocol and normal anatomy  41–42, 41–42, 44, 46, 55, 61–64 injuries  81–83, 82–87, 89–92, 90–93

medial–lateral drawer instability, shoulder joint  36 medial meniscal release  209, 252–253, 258 medial parapatellar fibrocartilage  214, 215 median nerve  109, 113 meniscal injuries  207, 209, 244–250, 249–252, 258, 264 meniscofemoral ligament  216 meniscotibial ligament  210, 216 mesotendon  42, 43, 80, 80–81 metastatic disease  182 microfracture chisels elbow joint  150–152, 151–153, 159, 173, 175–176 problems and complications  299, 299 shoulder joint  67–69, 71 stifle joint  260, 271 midbody meniscal release  255–258, 258 moth‐eaten cartilage elbow joint  130–139, 132, 134, 136, 138 shoulder joint  96, 97 MPRT see multipurpose rigid telescope MRI see magnetic resonance imaging multipurpose rigid telescope (MPRT)  3–5, 4, 4

n

necrotic bone, shoulder joint  58, 65 neoplasia elbow joint  181–182, 182 hip joint  206, 206 shoulder joint  100–102, 103 stifle joint  269–270, 273 nerve injury  301 elbow joint  113 hip joint  193 radiocarpal joint  187–188 shoulder joint  40–41 stifle joint  213 tibiotarsal joint  278

o

OATS technique  263 OCD see osteochondritis dissecans operative cannulas  6–8, 7, 7 operative debris  298–299, 299–300

operative portals elbow joint  111–113, 112 hip joint  176–177, 177 radiocarpal joint  187, 188, 191 shoulder joint  39–40, 39–40 stifle joint  211, 211 tibiotarsal joint  276–278, 277 osteoarthritis elbow joint  184 shoulder joint  62 tibiotarsal joint  289, 289–291 osteocartilaginous flaps  176–177 osteocartilaginous grafts  263 osteochondritis dissecans (OCD) elbow joint  108–112, 122–123, 167–175, 167–177 instrumentation and equipment  1–3 shoulder joint  36–40, 37–39, 45, 47–73, 48–73, 53 stifle joint  237, 240, 259–263, 260–264 surgical technique and procedure  24–26, 25, 30 tibiotarsal joint  276–286, 280–287 osteochondromatosis  274 osteophytes elbow joint  108, 111–113, 159–164, 160–165 hip joint  198–201, 198–199, 201–202, 206 shoulder joint  62, 74, 74, 95–96, 96 stifle joint  222, 224–229, 226–236, 264, 267 tibiotarsal joint  281, 286, 286–287 osteoporosis  158

p

pain and pain management elbow joint  108, 123 postoperative care  23–24 shoulder joint  36 surgical technique and procedure  23–24 pale villi shoulder joint  50, 61–62, 76, 84, 86–87, 89, 92–93, 96 stifle joint  221, 222, 225–226, 232, 264, 266–267 pars nodosa  119, 121–122 patellar fracture management  266, 268

Index

patellar luxation  270, 273 patient preparation, positioning, and operating room setup elbow joint  25, 26–28, 28, 108–109 hip joint  29, 29, 192 radiocarpal joint  27, 28, 187 shoulder joint  24–26, 25–27, 36–37, 37 stifle joint  24, 24, 29, 30, 210 tibiotarsal joint  30, 31, 276 patient size  303 patient support  23 peri‐articular fluid accumulation  300 petechiae  223, 227, 231 physiologic saline solution  15–16, 31–32, 32 plica, stifle joint  213, 214 popliteal tendon avulsion  208, 219, 220–221, 268–269, 270–271 portal sites and placement elbow joint  109–113, 109–112 hip joint  192, 193 radiocarpal joint  187, 188 shoulder joint  37–40, 37–40 stifle joint  210–213, 211–213 surgical technique and procedure  31–34, 31–33 tibiotarsal joint  276–278, 277–278 postoperative care  23–24 power instruments  12–15, 12–15, 12 power shavers elbow joint  130, 145, 147–160, 152–158, 162–163, 174 instrumentation and equipment  12–14, 12–14 problems and complications  292, 295, 296, 297, 301–303, 301–303 shoulder joint  66, 70–71, 99 stifle joint  221, 236, 246–252, 251–256 pressure assisted flow systems  16 problems and complications  292–304 articular cartilage damage  292–296, 293–295 bone fragment displacement  298, 298–299 contraindications  303 failure to enter the joint  292

infection  300, 300 instrument damage  301–303, 301–303 nerve injury  301 operative debris  298–299, 299–300 peri‐articular fluid accumulation  300 red out  299–300, 300 soft tissue damage  296–298, 296–297 vascular injury  300–301

q

quadriceps tendon  213, 214–215

r

radial head cartilage  136–145, 138–149 radial head osteophytes  111–113, 159–161, 160–163 radiocarpal joint  187–191 examination protocol and normal anatomy  188, 188–189 fractures  189–190, 189–191 immune‐mediated erosive arthritis  190 indications for arthroscopy  187 nerves of concern  187–188 patient preparation, positioning, and operating room setup  27, 28, 187 portal sites and placement  187, 188 soft tissue injuries  190 radiofrequency electrocautery see electrocautery radiography  1–2 elbow joint  160 shoulder joint  95–96 stifle joint  207–209, 208 see also computed tomography; magnetic resonance imaging red out  299–300, 300 Ringer’s solution  15–16, 31–32, 32 rough pink bone surface  57

s

saphenous artery/vein  278 sciatic nerve  193 sclerotic bone fragments  145, 152, 153–154, 157

screw placement/fixation  81, 102, 177, 180, 189 semilunar notch elbow dysplasia  135–136, 139, 140–141, 156 examination protocol and normal anatomy  114–116, 114–117, 121–122 incomplete ossification of the humeral condyle  183 osteochondritis dissecans  172 portal sites and placement  110 problems and complications  293–294, 299 septic arthritis  292, 300, 303 shavers see power shavers sheaths  5–6, 6–7, 6 shoulder joint  36–107 arthroscopy‐assisted intra‐articular fracture repair  100–101, 101–102 bicipital tendon injuries  73–81, 74–81 biopsy of intra‐articular neoplasia  100–102, 103 chondromalacia  48–59, 49–56, 53, 60–64, 75, 97–98, 102–104, 102–105 egress portals  40 examination protocol and normal anatomy  41–47, 41–47 glenoid cartilage defects  102–103, 103–104 indications for arthroscopy  36 infraspinatus muscle contracture  104–105, 105–106 nerves of concern  40–41 operative portals  39–40, 39–40 osteochondritis dissecans  36–40, 37–39, 45, 47–73, 48–73, 53 lesion removal and management  59–73, 65–73 patient preparation, positioning, and operating room setup  24–26, 25–27, 36–37, 37 portal sites and placement  37–40, 37–40 soft tissue injuries with/without shoulder instability  81–95, 82–94 telescope portals  37–39, 37–38

309

310

Index

shoulder joint (cont’d) ununited caudal glenoid ossification center  37–39, 37–39, 95–99, 95–99 ununited supraglenoid tubercle  76, 100, 100–101 smooth brown bone  58 smooth pink bone surface  69 soft tissue injuries elbow joint  107, 109–110, 131–133, 131 hip joint  203–204, 203–204 problems and complications  296–298, 296–297 radiocarpal joint  190 shoulder joint  81–95, 82–94 stifle joint  207–208 tibiotarsal joint  287 soft tissue sarcoma  166 stem cell therapy elbow joint  167, 175, 180 shoulder joint  81, 87, 91, 94 stifle joint  263 tibiotarsal joint  286 stifle joint  207–275 biopsy of intra‐articular neoplasia  269–270, 273 caudal cruciate ligament  207–208, 216, 217–218, 221, 227–228, 230, 235, 242, 244–245, 251–252, 258, 259 chondromalacia  225, 228–238, 234–241, 261, 263, 270–273, 273 cranial cruciate ligament  207–210, 208, 213, 213, 216, 217, 219, 221–258, 221–259 degenerative joint disease  208–210, 270–273 discoid meniscus  273, 273 drawer instability  207 egress portals  211–213, 211–212 examination protocol and normal anatomy  213–221, 214–221 indications for arthroscopy  207–210, 208 isolated meniscal injuries  258 long digital extensor tendon injuries  216–219, 219–220, 224, 229, 268, 269 meniscal injuries  207, 209, 244–250, 249–252, 258, 264

nerves of concern  213 operative portals  211, 211 osteochondritis dissecans  237, 240, 259–263, 260–264 osteochondromatosis  274 osteophytes  222, 224–229, 226–236, 264, 267 patellar fracture management  266, 268 patellar luxation  270, 273 patient preparation, positioning, and operating room setup  24, 24, 29, 30, 210 popliteal tendon avulsion  208, 219, 220–221, 268–269, 270–271 portal sites and placement  210–213, 211–213 soft tissue injuries  207–208 stifle stabilization failures  264, 265–267 synovial membrane petechiae  223, 227, 231 synovitis  270–273 telescope portals  210–211, 212 vascular pannus  223–224, 228–230 villus synovial reaction  211–213, 216, 219–222, 222, 227, 231, 233, 238–240, 238, 244, 246, 264, 265, 267 subluxation injury, hip joint  199–200, 199, 203–204, 203–204 subscapularis tendon examination protocol and normal anatomy  41–44, 42, 44 osteochondritis dissecans  55, 63, 75 soft tissue injuries  82–84, 83–87, 88, 91–92, 91–94 superficial radial nerve  187–188 supraglenoid tubercle  42, 42, 69–70, 74–80, 76–80, 298–299 see also ununited supraglenoid tubercle suprapatellar pouch  211–214, 212–215, 221–225, 222–227, 230–238, 260, 262, 267 suprascapular nerve  40–41 supraspinatus tendon  84–85, 87 supratrochlear foramen  118–119, 120

surgical technique and procedure  23–35 anesthesia, patient support, and pain management  23 elbow joint  25, 26–28, 28 hip joint  29, 29 patient preparation, positioning, and operating room setup  24–31, 24–30 portal sites and placement  31–34, 31–33 postoperative care  23–24 radiocarpal joint  27, 28 shoulder joint  24–26, 25–27 stifle joint  24, 24, 29, 30 tibiotarsal joint  30, 31 switching sticks  8, 10 synovial cell sarcoma  272 synovial membrane petechiae  223, 227, 231 synovitis elbow joint  147 hip joint  200 shoulder joint  59, 63 stifle joint  270–273 see also villus synovial reaction

t

telescope breakage  302, 302 telescope portals elbow joint  109–111, 110–111 hip joint  176, 177 radiocarpal joint  171 shoulder joint  37–39, 37–38 stifle joint  210–211, 212 tibiotarsal joint  276–277, 277 telescope sheaths  5–6, 6–7, 6 tenotomy  78–79, 79–80 thermal modification  90–93, 93–94 tibial nerve  278 tibiotarsal joint  276–291 arthroliths  289, 290 chondromalacia  283–286 egress portals  277, 278 examination protocol and normal anatomy  278–279, 278–280 immune‐mediated erosive arthritis  287 indications for arthroscopy  276 intra‐articular fracture management  286, 287–288 nerves of concern  278

Index

operative portals  277, 277 osteoarthritis  289, 289–291 osteochondritis dissecans  276–286, 280–287 osteophytes  281, 286, 286–287 patient preparation, positioning, and operating room setup  30, 31, 276 portal sites and placement  276–278, 277–278 soft tissue injuries  287 telescope portals  276–277, 277 Tight Rope stabilization, stifle joint  264, 266 TPLO surgery  209–210, 252, 255, 258, 259, 264, 266–268 TPO see triple pelvic osteotomy transverse acetabular ligament  193, 196 transverse humeral ligament  42, 44 triangulation  24, 24, 33 triple pelvic osteotomy (TPO)  192 trochlear groove  214–216, 214–216, 223–229, 226–228, 230–231, 234–235 trochlear notch  138–139, 139–143

u

UAP see ununited anconeal process UCGOC see ununited caudal glenoid ossification center ulnar articular cartilage  135, 138–139, 140, 142 ulnar nerve  113 ultrasound  36, 47, 73–76, 82, 85, 184 ununited anconeal process (UAP)  108–109, 113, 176–180, 178–180 ununited caudal glenoid ossification center (UCGOC)  95–99, 95–99 portal sites and placement  37–39, 37–39 surgical technique and procedure  24–26, 25 ununited medial humeral epicondyle  183–184, 183 ununited supraglenoid tubercle (USGT)  76, 100, 100–101

v

VAPR electrocautery see electrocautery vascular injury  300–301

vascularity  42, 78–79, 114, 201, 224–225 vascular pannus hip joint  201, 202 shoulder joint  74 stifle joint  223–224, 228–230 tibiotarsal joint  286, 287 video system tower  17–20, 17–20, 18 villus synovial reaction elbow joint  130–131, 146, 147, 159, 161, 164, 174 hip joint  201, 201–202 radiocarpal joint  189 shoulder joint  59, 59, 61–63, 73–74, 74–76, 79, 86–87, 89–90, 91, 105 stifle joint  211–213, 216, 219–222, 222, 227, 231, 233, 238–240, 238, 244, 246, 264, 265, 267 tibiotarsal joint  280, 282–284, 286, 286–287

w

white speckled avascular bone  55–56, 66

311

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