Morrey's The Elbow and Its Disorders [4 ed.]

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Dedication As I was preparing the front material for the Fourth Edition of The Elbow and Its Disorders, my father passed away at age 91. It is with great humility as well as a tremendous sense of loss, but also pride that I dedicate this fourth volume to my father, Alfred E. Morrey, Jr. My dad was a chemical engineer and worked in the petroleum industry all of his life. His professional background and skills were instrumental in my formative years in teaching, observation, precision, accuracy, practicality and problem solving. In many ways these features of engineering are not dramatically different from the requirements of the orthopedic surgeon. But, more importantly than this, my father was my role model. He was openminded and objective and strongly believed in the concept of service. He avoided assuming information as being factual unless it had been demonstrated to be so. But probably the most important characteristic was his desire and stimulus for myself and my siblings to contribute to society and to “give a full days measure”. I have thought of my father regularly throughout my career and with his passing on July 13, 2008, it seems fitting to dedicate this effort to him. He had all three prior volumes proudly displayed in his library. Bernard F. Morrey, MD

CONTRIBUTORS

Julie E. Adams, MD Assistant Professor, Department of Orthopaedic Surgery, University of Minnesota School of Medicine, Minneapolis, Minnesota Fractures of the Olecranon

Robert A. Adams, MA, OPA-C Adjunct Faculty Clinical Coordinator, University of Wisconsin-La Crosse, La Crosse, Wisconsin; Assistant Professor, Mayo College of Medicine, Rochester, Minnesota; Physician Assistant, Mayo Clinic, Rochester, Minnesota Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis; Total Elbow Arthroplasty for Primary Osteoarthritis; Wear and Elbow Replacement

Christopher S. Ahmad, MD Associate Professor, Orthopaedic Surgery, Center for Shoulder, Elbow and Sports Medicine, Columbia University College of Physicians and Surgeons; Attending, Orthopaedic Surgeon, New York Orthopaedic Hospital, Columbia University, New York, New York Arthroscopy in the Throwing Athlete; Diagnosis and Treatment of Ulnar Collateral Ligament Injuries in Athletes

Gilberto J. Alvarado, MD Orthopedic Sports Medicine Fellow, Nirschl Orthopaedic Center for Sports Medicine and Joint Reconstruction, Arlington, Virginia Tennis Elbow Tendinosis

Peter C. Amadio, MD Professor of Orthopedics, Mayo Clinic College of Medicine; Consultant in Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Congenital Abnormalities of the Elbow

Kai-Nan An, PhD Professor, and Director, Biomechanics Laboratory, Mayo Clinic, Rochester, Minnesota Biomechanics of the Elbow; Functional Evaluation of the Elbow

Karen L. Andrews, MD Assistant Professor of Physical Medicine and Rehabilitation, College of Medicine, Mayo Clinic, Rochester, Minnesota Elbow Disarticulation Amputation

Robert D. Beckenbaugh, MD Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota Arthrodesis

Richard A. Berger, MD, PhD Professor of Orthopedic Surgery and Anatomy, Mayo Clinic College of Medicine; Consultant, Division of Hand Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Overuse Syndrome

Thomas H. Berquist, MD, FACR Professor of Diagnostic Radiology, Mayo Clinic College of Medicine, Rochester, Minnesota; Consultant, Mayo Clinic – Jacksonville, Jacksonville, Florida Diagnostic Imaging of the Elbow

Allen T. Bishop, MD Professor of Orthopedic Surgery, Mayo Clinic College of Medicine; Consultant, Department of Orthopedic Surgery, and Chair, Division of Hand Surgery, Mayo Clinic, Rochester, Minnesota Soft Tissue Coverage of the Elbow; Flaccid Dysfunction of the Elbow

Kenneth P. Butters, MD Consultant, Hand Surgery, Department of Orthopedic Surgery, University of Oregon, Eugene, Oregon Septic Arthritis

Andrea Celli, MD Consultant Orthopaedic and Traumatology Surgeon, Orthopaedic and Traumatology Department, University of Modena e Reggio Emilia, Modena, Italy Triceps Insufficiency Following Total Elbow Arthroplasty

Emilie Cheung, MD Assistant Professor, Medical Center Line, and Stanford Hospital and Clinics, Stanford University, Stanford, California Treatment of the Infected Total Elbow Arthroplasty v

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Contributors

Akin Cil, MD Assistant Professor of Orthopaedics, Department of Orthopaedic Surgery, University of Missouri Kansas City; Attending Surgeon, Department of Orthopaedic Surgery, Truman Medical Center, Kansas City, Missouri Synovectomy of the Elbow

Mark S. Cohen, MD Professor, Director, Orthopaedic Education, and Director, Section of Hand and Elbow Surgery, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois Advanced Techniques: Arthroscopic Management of Lateral Epicondylitis

Patrick M. Connor, MD Clinical Faculty, Shoulder and Elbow Surgery/Sports Medicine, and Trauma Surgery, Orthopaedic Surgery Residency Program, Carolinas Medical Center, Charlotte, North Carolina Total Elbow Arthroplasty for Juvenile Rheumatoid Arthritis

William P. Cooney, MD Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota Elbow Arthroplasty: Historical Perspective and Emerging Concepts

Ralph W. Coonrad, MD Associate Clinical Professor, Department of Orthopedic Surgery, Duke University; Medical Director Emeritus, Lenox Baker Children’s Hospital, Duke University, Durham, North Carolina Nonunion of the Olecranon and Proximal Ulna

Joshua S. Dines, MD Clinical Instructor, Orthopedic Surgery, Weill Cornell Medical College; Assistant Attending, Sports Medicine and Shoulder Service, The Hospital for Special Surgery, New York, New York Articular Injuries in the Athlete

James H. Dobyns, MD Professor of Orthopedics, and Emeritus Staff, Mayo Clinic College of Medicine, Rochester, Minnesota, and University of Texas San Antonio Health Science Center, San Antonio, Texas Congenital Abnormalities of the Elbow

Neal S. ElAttrache, MD Associate Clinical Professor, Department of Orthopaedics, Keck School of Medicine, University of Southern California; Director, Sports Medicine Fellowship, Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California Arthroscopy in the Throwing Athlete; Diagnosis and Treatment of Ulnar Collateral Ligament Injuries in Athletes; Articular Injuries in the Athlete

Larry D. Field, MD Clinical Instructor, Department of Orthopaedic Surgery, University of Mississippi School of Medicine; Director, Upper Extremity Service, Mississippi Sports Medicine and Orthopaedic Center, Jackson, Mississippi Diagnostic Arthroscopy: Indications, Portals, and Techniques; Management of Loose Bodies and Other Limited Procedures; Arthroscopic Management of the Stiff Elbow

Gerard T. Gabel, MD Clinical Associate Professor, Department of Orthopedic Surgery, Baylor College of Medicine, Houston, Texas Medial Epicondylitis

David R. J. Gill, MD, ChB, FRACS Joondalup Health Campus, Joondalup, Western Australia, Australia Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis

E. Richard Graviss, MD Professor of Radiology, St. Louis University School of Medicine; Pediatric Radiology, Cardinal Glennon Children’s Hospital, St. Louis, Missouri Imaging of the Pediatric Elbow

G. Dean Harter, MD Associate, Department of Orthopaedic Surgery, Chief, Shoulder and Elbow Institute, Program Director, Orthopaedic Surgery Residency, Geisinger Health System, Danville, Pennsylvania Ectopic Ossification About the Elbow

Alan D. Hoffman, MD Associate Professor of Radiology, Mayo Clinic College of Medicine; Consultant in Radiology – Pediatric Radiology, Mayo Clinic, Rochester, Minnesota Imaging of the Pediatric Elbow

Terese T. Horlocker, MD Professor of Anesthesiology and Orthopedics, Mayo Clinic, Rochester, Minnesota General and Regional Anesthesia and Postoperative Pain Control

Jeffery S. Hughes, MB, FRACS Orthopaedic Consultant, North Shore Private Hospital, Sydney, Australia Injury of the Flexors of the Elbow: Biceps Tendon Injury; Unlinked Arthroplasty: Distal Humeral Hemiarthroplasty

Srinath Kamineni, MBBCh, FRCS-Ed, FRCSOrthopaedics and Trauma, PhD Professor of Bioengineering, Brunel University – School of Engineering and Design; Consultant Elbow, Shoulder, Upper Limb Surgeon, and Clinical Lead, Upper Limb Unit, Cromwell Hospital, London, United Kingdom Distal Humeral Fractures–Acute Total Elbow Arthroplasty

Contributors

Graham J. W. King, MD, MSc, FRCSC Professor, Department of Surgery, University of Western Ontario; Chief of Orthopaedic Surgery, St. Joseph’s Health Centre, London, Ontario, Canada Unlinked Arthroplasty: Unlinked Total Elbow Arthroplasty; Unlinked Arthroplasty: Convertible Total Elbow Arthroplasty; Revision of Failed Total Elbow Arthroplasty with Osseous Integrity

Sandra L. Kopp, MD Assistant Professor of Anesthesiology, Mayo Clinic, Rochester, Minnesota General and Regional Anesthesia and Postoperative Pain Control

Tomasz K. W. Kozak, FRACS West Perth, Western Australia, Australia Total Elbow Arthroplasty for Primary Osteoarthritis

Mikko Larsen, MD Research Fellow, Microvascular Research Laboratory, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota; Resident in Training, Department of Plastic and Reconstructive Surgery, V.U. Medical Center, Amsterdam, The Netherlands Flaccid Dysfunction of the Elbow

A. Noelle Larson, MD Resident in Orthopedics, Department of Orthopedics, Mayo Clinic, Rochester, Minnesota Hinged External Fixators of the Elbow; Interposition Arthroplasy of the Elbow

Susan G. Larson, MS, PhD Professor, Department of Anatomical Sciences, School of Medicine, Stony Brook University Medical Center, Stony Brook, New York Phylogeny

Brian P. Lee, MD Orthopaedic Associates, Singapore, Singapore Wear and Elbow Replacement

Robert L. Lennon, DO Associate Professor of Anesthesiology, Mayo Medical School; Supplemental Consultant, Mayo Clinic, Rochester, Minnesota General and Regional Anesthesia and Postoperative Pain Control

R. Merv Letts, MD, MSc, FRCSC, FACS Consultant Pediatric Orthopaedic Surgeon, Sheikh Khalifa Medical City, Abu Dhabi, United Arab Emirates Dislocations of the Child’s Elbow

Harvinder S. Luthra, MD Professor of Medicine, Department of Rheumatology, Mayo Clinic, Rochester, Minnesota Rheumatoid Arthritis

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Alex A. Malone, MBBS, MRCS (Eng), FRCS (Tr & Orth) Consultant Orthopaedic Surgeon, Christchurch Hospital, Canterbury, New Zealand; Senior Lecturer in Orthopaedics with an interest in Upper Limb Surgery, Christchurch School of Medicine, Otago University, New Zealand; Honorary Consultant, Shoulder and Elbow Unit, The Royal National Orthopaedic Hospital, Stanmore, United Kingdom; Honorary Lecturer, Department of Surgery, University College London, London, United Kingdom Phylogeny

Pierre Mansat, MD, PhD Professor of Orthopedics and Traumatology, Faculté Medecine Toulouse/Purpan, Université Paul Sabatier, and Service d’Orthopedie/Traumatologie, Unité du Membre Superieur, Centre Hospitalier Universitaire Purpan, Toulouse, France Extrinsic Contracture: Lateral and Medial Column Procedures

Thomas G. Mason, MD Associate Professor of Internal Medicine and Pediatrics, Mayo Clinic College of Medicine; Consultant in Adult and Pediatric Rheumatology, Mayo Clinic, Rochester, Minnesota Seronegative Inflammatory Arthritis

Glen A. McClung II, MD Commonwealth Orthopaedic Surgeons, Lexington, Kentucky Diagnostic Arthroscopy: Indications, Portals, and Techniques

Amy L. McIntosh, MD Associate Clinical Professor, Mayo Clinic, Rochester, Minnesota Complications of Supracondylar Fractures of the Elbow

Steven L. Moran, MD Assistant Professor of Orthopedics and Plastic Surgery, Mayo College of Medicine, and Mayo Clinic, Rochester, Minnesota Soft Tissue Coverage of the Elbow

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Contributors

Bernard F. Morrey, MD Professor of Orthopedic Surgery, Mayo Medical School; Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Anatomy of the Elbow Joint; Biomechanics of the Elbow; Physical Examination of the Elbow; Functional Evaluation of the Elbow; Surgical Exposures of the Elbow; Principles of Elbow Rehabilitation; Splints and Bracing at the Elbow; Proximal Ulnar Fractures in Children; Dislocations of the Child’s Elbow; Post-Traumatic Elbow Stiffness in Children; Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation; Radial Head Fracture: Prosthetic Radial Head Replacement; Nonunion of the Olecranon and Proximal Ulna; Coronoid Process and Monteggia Fractures; Complex Instability of the Elbow; Chronic Unreduced Elbow Dislocation; Ectopic Ossification About the Elbow; Extrinsic Contracture: Lateral and Medial Column Procedures; Hinged External Fixators of the Elbow; Injury of the Flexors of the Elbow: Biceps Tendon Injury; Rupture of the Triceps Tendon; Complications of Elbow Arthroscopy; The Future of Arthroscopy of the Elbow; Medial Epicondylitis; Surgical Failure of Tennis Elbow; Elbow Arthroplasty: Historical Perspective and Emerging Concepts; Unlinked Arthroplasty: Radiohumeral Arthrosis: Anconeus Arthroplasty and Capitellar Prosthetic Replacement; Linked Elbow Arthroplasty: Rationale, Indications, and Surgical Technique; Linked Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis; Total Elbow Arthroplasty for Juvenile Rheumatoid Arthritis; Semiconstrained Elbow Replacement: Results in Traumatic Conditions; Total Elbow Arthroplasty as a Salvage for the Fused Elbow; Total Elbow Arthroplasty for Primary Osteoarthritis; Complications of Elbow Replacement Arthroplasty; Treatment of the Infected Total Elbow Arthroplasty; Triceps Insufficiency Following Total Elbow Arthroplasty; Wear and Elbow Replacement; Revision of Failed Total Elbow Arthroplasty with Osseous Integrity; Revision of Failed Total Elbow Arthroplasty with Osseous Deficiency; Nonimplantation Salvage of Severe Elbow Dysfunction; Synovectomy of the Elbow; Interposition Arthroplasty of the Elbow; Primary Osteoarthritis: Ulnohumeral Arthroplasty; Septic Arthritis; Neoplasms of the Elbow; Loose Bodies; Bursitis; The Elbow in Metabolic Disease

Matthew Morrey, MD Senior Orthopaedic Resident, Department of Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota Hinged External Fixators of the Elbow

Scott J. Mubarak, MD Clinical Professor, Department of Orthopedics, University of California, San Diego; Director of Orthopedic Program, Children’s Hospital, San Diego, California Complications of Supracondylar Fractures of the Elbow

Robert P. Nirschl, MD, MS Associate Clinical Professor, Georgetown University School of Medicine, Washington, DC; Director, Sports Medicine Fellowship Programs, Nirschl Orthopaedic Center for Sports Medicine and Joint Reconstruction, Arlington, Virginia; Attending Orthopedic Surgeon, Virginia Hospital Center, Arlington, Virginia Tennis Elbow Tendinosis

Shawn W. O’Driscoll, PhD, MD Professor of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Continuous Passive Motion; Current Concepts in Fractures of the Distal Humerus; Elbow Dislocations; Complex Instability of the Elbow

Nicole M. Orzechowski, DO Instructor of Internal Medicine, Mayo Clinic College of Medicine; Mayo Clinic, Rochester, Minnesota Seronegative Inflammatory Arthritis

Panayiotis J. Papagelopoulos, MD, DSc Associate Professor of Orthopaedics, Athens University Medical School; Consultant, First Department of Orthopaedics, Attikon University General Hospital, Athens University Medical School, Athens, Greece Nonunion of the Olecranon and Proximal Ulna

Hamlet A. Peterson, MD, MS Emeritus Professor of Orthopedic Surgery, Mayo Medical School; Emeritus Consultant in Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Physeal Fractures of the Elbow

Douglas J. Pritchard, AB, MS, MD Orthopedic Surgery, Retired, Mayo Clinic, Rochester, Minnesota Neoplasms of the Elbow

Matthew L. Ramsey, MD Associate Professor of Orthopaedic Surgery, Thomas Jefferson University, and Rothman Institute, Philadelphia, Pennsylvania Total Elbow Arthroplasty for Distal Humerus Nonunion and Dysfunctional Instability

William D. Regan, MD, FRCS(C) Associate Professor, Department of Orthopaedics, University of British Columbia; Associate Head, Department of Orthopaedics, and Head, Division of Upper Extremity Surgery, University Hospital, Vancouver, British Columbia, Canada Physical Examination of the Elbow; Coronoid Process and Monteggia Fractures

Anthony A. Romeo, MD Associate Professor, and Director, Section of Shoulder and Elbow, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois Advanced Techniques: Arthroscopic Management of Lateral Epicondylitis

Joaquin Sanchez-Sotelo, MD, PhD Associate Professor of Orthopedics, Mayo Clinic College of Medicine; Consultant in Orthopedic Surgery, Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Nonunion and Malunion of Distal Humerus Fractures; Lateral Collateral Ligament Insufficiency; Total Elbow Arthroplasty for Distal Humerus Nonunion and Dysfunctional Instability; Revision of Failed Total Elbow Arthroplasty with Osseous Deficiency; Hematologic Arthritis

Contributors

Felix H. Savoie III, MD Lee Schlesinger Professor, Shoulder, Elbow and Sports Surgery, Department of Orthopaedic Surgery, Tulane University; Chair, Division of Sports Medicine, Tulane Institute of Sports Medicine, New Orleans, Louisiana Diagnostic Arthroscopy: Indications, Portals, and Techniques; Management of Loose Bodies and Other Limited Procedures; Arthroscopic Management of the Stiff Elbow; Advanced Techniques: Arthroscopic Radial Ulnohumeral Ligament Reconstruction for Posterolateral Rotatory Instability of the Elbow; The Future of Arthroscopy of the Elbow

Alberto G. Schneeberger, MD Privatdozent, University of Zurich; Consultant, Shoulder and Elbow Surgery, Zurich, Switzerland Semiconstrained Elbow Replacement: Results in Traumatic Conditions

William J. Shaughnessy, MS, MD Associate Professor of Orthopedic Surgery, Mayo Medical School; Member, Division of Pediatric Orthopedics, Mayo Clinic, Rochester, Minnesota Osteochondritis Dissecans

Alexander Y. Shin, MD Professor, Orthopaedic Surgery, Mayo Clinic School of Medicine; Consultant, Orthopaedic Surgery, Mayo Clinic, Rochester, Minnesota Flaccid Dysfunction of the Elbow

Thomas C. Shives, MD Professor of Orthopedics, Mayo Clinic, Rochester, Minnesota Elbow Disarticulation Amputation

Jay Smith, MD Associate Professor of Physical Medicine and Rehabilitation, Mayo Clinic College of Medicine; Consultant, Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota Principles of Elbow Rehabilitation

Robert J. Spinner, MD Professor, Departments of Neurosurgery, Orthopedics and Anatomy, Mayo Clinic College of Medicine; Consultant, Department of Neurologic Surgery and Orthopedics, Mayo Clinic, Rochester, Minnesota Nerve Entrapment Syndromes

Anthony A. Stans, MD Assistant Professor, and Chair, Division of Pediatric Orthopedics, Mayo Clinic, Rochester, Minnesota Supracondylar Fractures of the Elbow in Children; Fractures of the Neck of the Radius in Children; Proximal Ulnar Fractures in Children; Post-Traumatic Elbow Stiffness in Children

Scott P. Steinmann, MD Consultant, Professor of Orthopedics Mayo Clinic College of Medicine, Rochester, Minnesota Fractures of the Olecranon

J. Clarke Stevens, MD Professor of Neurology, Mayo Medical School, Rochester, Minnesota Neurotrophic Arthritis

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Kristen B. Thomas, MD Assistant Professor of Radiology, Mayo Clinic College of Medicine; Consultant in Radiology – Pediatric Radiology, Mayo Clinic, Rochester, Minnesota Imaging of the Pediatric Elbow

Nho V. Tran, MD Assistant Professor of Plastic Surgery, Mayo College of Medicine, and Mayo Clinic, Rochester, Minnesota Soft Tissue Coverage of the Elbow

Stephen D. Trigg, MD Associate Professor, Orthopaedics and Hand Surgery, Mayo Clinic Medical School Hand Surgery, Mayo Medical School, Rochester, Minnesota; Hand Surgeon, Department of Orthopaedics, and Medical Director, Outpatient Surgery Center, Mayo Clinic, Jacksonville, Florida Pain Dysfunction Syndrome

K. Krishnan Unni, MD Emeritus Professor of Pathology, Departments of Anatomic Pathology, Orthopedic Oncology, and Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota Neoplasms of the Elbow

Francis Van Glabbeek, MD, PhD Professor of Functional Anatomy and Orthopaedics, University of Antwerp; Vice Chair, Department of Orthopaedics and Traumatology, University Hospital Antwerp, Antwerp, Belgium Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation

Ann E. Van Heest, MD Professor, Department of Orthopaedic Surgery, University of Minnesota, Minneapolis; Gillette Children’s Specialty Healthcare, St. Paul, Minnesota Spastic Dysfunction of the Elbow

Roger P. van Riet, MD, PhD Orthopaedic Surgeon, Elbow Surgery, Monica Hospital, Deurne, Antwerp, Belgium Radial Head Fracture: General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation

Ilya Voloshin, MD Assistant Professor, University of Rochester; Director, Shoulder and Elbow Service, University of Rochester Medical Center, Rochester, New York Complications of Elbow Replacement Arthroplasty

Ken Yamaguchi, MD Sam and Marilyn Fox Distinguished Professor of Orthopaedic Surgery, and Chief, Shoulder and Elbow Service, Washington University School of Medicine, St. Louis, Missouri Treatment of the Infected Total Elbow Arthroplasty

Mark E. Zobitz, MS Assistant Professor, Biomechanics Laboratory, Mayo Clinic, Rochester, Minnesota Biomechanics of the Elbow

P R E FA C E

Since the first edition of The Elbow and Its Disorders in 1983 I am extremely proud to hear such comments regarding the original and previous efforts such as “the definitive word in elbow surgery”. Such statements and confidence is a source of tremendous pride and also motivation to continue to improve. In the spirit of the original goal of providing a source of reliable information that will improve patient care, we continue to be focused on this initial desire to provide clear, concise, current, accurate, relevant and intelligible information that is easily accessible. I have a simple personal requirement for the timing of subsequent editions of this book. This is to wait until I feel as though there has been sufficient additional information to justify another volume. This requirement has been met with this particular effort. Thus, I am very pleased along with my co-authors to have completed the current volume. The overall organization, hope and effort to be a comprehensive reference has been maintained with an increased emphasis on surgical technique which is an ever growing and relevant need of the orthopedic community. We are, therefore, specifically pleased to offer video clips in a number of chapters that do complement and enhance the practical and useful learning experience.

The exciting advances in elbow arthroscopy are more extensively explored in the current volume. Innovative opportunities with regard to prosthetic joint replacement are also discussed in the current volume, along with nonprosthetic options such as anconeus arthroplasty. In fact we are pleased to observe considerable enhancement in the majority of chapters. As always I am deeply appreciative and humbled by those who have contributed material, thoughts, and insights over the years, particularly Doctors O’Driscoll, Steinmann, SanchezSotelo and my other partners at the Mayo Clinic. Finally, I should note that this edition is an opportunity to introduce my partner and colleague, Joaquin Sanchez-Sotelo, who has assisted me in the preparation of the current volume, and who has shown an insightful and substantive commitment to the practice of elbow surgery. It remains our hope that the reader will continue to find this text relevant both from the perspective of arriving at a diagnosis of a difficult problem, understanding the options and potential outcome of various interventions, as well insight with regard to how surgical techniques might be executed. Bernard F. Morrey, MD

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Acknowledgment I wish to acknowledge with genuine appreciation all the input and insight I received from orthopedic colleagues around the world, especially my colleagues, residents and fellows at the Mayo Clinic. I also wish to express my most sincere appreciation to Professor Gerber for the thoughtful and gracious comments which he made in the “forward” of this edition. The administrative efforts of my associate of 30 years, Bob Adams, to help find that one unique patient or x-ray has always been a tremendous and an essential asset, as is the secretarial and administrative efforts of my secretary, Sherry Koperski, and the numerous details and competencies provided by Donna Riemersma in the preparation of this manuscript. Finally, and as always, I want to expressly acknowledge my wife, Carla, who has now lived through and encouraged me in the preparation of four editions of “Disorders”. I am deeply appreciative of all the support I have received from Carla, our children, and from the profession throughout my career.

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FOREWORD

Via internet we can gain access to almost any medical data within a few mouse clicks. The most recent Journal articles including illustrations are at hand and most data banks allow us to get immediate access to related articles. If ever we decide to review an older publication not yet available in PDF format, it can be ordered within hours or very few days. Details of current surgical techniques are now reviewed in top quality video and DVD productions coming from leading international experts. The question is therefore inevitable whether the concept of a textbook is out of date and in fact, out of place. Unfortunately, many current textbooks are an assiduous compilation of more or less well digested original articles allowing at best for a cookbook approach to orthopaedics. These many textbooks may decorate a bookshelf but add nothing to the impressive number of references they quote and are superfluous. What could the value of a current textbook be and why would we use it? In this period of time, which Kipling characterizes by the probably unassailable lead of knowledge over wisdom, in a time where orthopaedics is taught in “training” programs – although we know that training refers to dogs and education refers to people – we, the upper extremity surgeons who all have a copy of the Third wait for the Fourth (!) Edition of “The Elbow and its Disorders”. Our expectations are living proof that there remains a role for a textbook, because there is a role for education, for educators, as role models who teach medicine based on an immense body of knowledge with wisdom, experience and compassion. There is a role for an instrument which puts scientific knowledge into perspective and helps us to apply knowledge most effectively to our patients. Dr. Morrey has spent decades observing, describing, and defining elbow problems. In a very systematic fashion, he has studied the identified problems with

collaborators and friends in the laboratory, and brought his insight back into clinical practice. Subsequently not only he and his pupils but surgeons throughout the world have validated and do validate the respective contributions in their patients. This textbook incorporates the knowledge gained from these and many other investigations. It discloses details which have taken the authors years to understand and apply. Yes, this textbook is comprehensive andprecise and yes, it certainly is the gold standard for elbow surgery on all continents. But I see the unique value of this book elsewhere. I see it in sharing an approach to clinical problem solving. Dr. Morrey shows how to identify a problem, how to evaluate a problem and finally how to solve it. The text may not be able to impart the human qualities of the editor, which certainly are large contributors of his success with very difficult patient problems. But the text unequivocally clearly states that orthopaedic surgery is not a manual but an intellectual discipline and that excellent orthopaedic care is an art based on science. Bernie, this textbook is a further testimony to you as a physician – scientist, educator and role model. It has been one of the privileges of my lifetime to meet you early in my career and to benefit from your wisdom and advice. For my next elbow problem, I – as many others – will consult this textbook and I am sure it will not only give me data but it will give me understanding. For any other very difficult problem, I hope I can continue to call you. Christian Gerber, MD, FRCS(hon) Professor and Chair Department of Orthopaedics University of Zürich Zürich, Switzerland

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Chapter 1 Phylogeny

CHAPTER

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Phylogeny Alex A. Malone and Susan G. Larson

INTRODUCTION The human elbow forms the link between brachium and forearm, controlling length of reach and orientation of the hand, and is one of our most distinctive anatomical regions. An appreciation of elbow phylogeny compliments anatomic knowledge in three ways: (1) it demonstrates how the elbow has evolved to facilitate specific functional demands, such as suspensory locomotion and dexterous manipulation; (2) it explains the functional significance of each morphologic feature; and (3) it assists in predicting the consequences of loss of such features through disease, injury, or treatment. Most of the characteristic features of the human elbow significantly predate the appearance of modern Homo sapiens. In fact, current evidence suggests that this morphology can be traced back to the common ancestor of humans and apes, extant about 15 to 20 million years ago (mya).

EVOLUTION OF THE VERTEBRATE ELBOW The distal humerus of pelycosaurs, the late Paleozoic (255 to 235 mya) reptiles that probably gave rise to more advanced mammal-like reptiles, possessed a bulbous capitellum laterally and medially. The articulation with the ulna was formed by two distinct surfaces: a slightly concave ventral surface and a more flat dorsal surface (Fig. 1-1).11 The proximal articular surface of the ulna was similarly divided into two surfaces separated by a low ridge. Reconstruction of the forelimb of these reptiles suggests that they walked with limbs splayed out to the side. The humerus was held more or less horizontal, the elbow flexed to 90 degrees, and the forearm was sagittally oriented. Forward motion was brought about by rotation of the humerus around its long axis, which propelled the body forward relative to the fixed forefoot. Elbow flexion and extension probably were useful only in side-to-side motions. The ulnohumeral joint, with its dual articular surfaces, was well suited to resist the valgus/varus stress produced by humeral

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rotation, and the proximal end of the radius was flat and triangular, precluding pronosupination. It appears, therefore, that stability rather than mobility was the major functional characteristic of the elbow of these late Paleozoic reptiles. Cynodonts, the more immediate ancestors of mammals from the Permo-Triassic period (235 to 160 mya), had their limbs underneath their bodies rather than at the sides. The distal humeral articular surface consisted of radial and ulnar condyles separated by a shallow groove (see Fig. 1-1). The proximal ulnar articular surface was an elongate spoon shape for articulation with the humeroulnar condyle. The lateral flange on the ulna for articulation with the radius was separated from this surface by a low ridge. This ridge articulated with the groove between the radial and ulnar condyles displaying some features in common with the “tongue and groove” (trochleariform) type of humeroulnar articulation characteristic of many modern mammals. Early mammals from the Triassic (210 to 160 mya) and Jurassic (160 to 130 mya) periods also had radial and ulnar condyles. However, the radial condyle was more protuberant than the ulnar, and the ulnar condyle was more linear and obliquely oriented (see Fig. 1-1). The two condyles were separated by an intercondylar groove. The ulnar notch had articular surfaces for both the ulnar and the radial condyles, each matching the configuration of the corresponding humeral surface. The oblique orientation of the humeroulnar joint resembled a spiral configuration, which helped to keep forearm movement in a sagittal plane as the humerus underwent a compound motion involving adduction, elevation, and rotation during propulsion. The trochleariform distal humeral articular surface in modern mammals largely came about by widening the intercondylar groove and the development of a ridge within it (see Fig. 1-1, bear). The articular surface on the proximal ulna is oblique in orientation, and the distal half retains an articulation with the ulnar condyle. This spiral trochlear configuration allows the forearm to move in a sagittal plane while maintaining the stability of ulnohumeral contact through the cam effect of the ulnar condyle during humeral rotation. Most small noncursorial mammals have maintained the spiral configuration of the trochlear articular surface observed in early mammals. In larger and more cursorial mammals, the trochlea displays various ridges and is narrower to improve stability, although at the expense of joint mobility. Only in the hominoid primates, which include humans, chimpanzees, gorillas, orangutans, and gibbons, is the medial aspect of the distal humeral articular surface truly trochleariform. In the next section, we discuss the functional significance of the unique aspects of the hominoid elbow joint.

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Part I Fundamentals and General Considerations

PHYLOGENY Hominoid primate (chimpanzee)

Graviportal mammal (elephant)

Cursorial mammal (gazelle)

Partly terrestrial mammal (bear)

FIGURE 1-1

Generalized mammal (tree shrew)

Prototherian Cretaceous ~100 mya

Jurassic mammal ~155 mya

Late Triassic mammal ~215 mya

Cynodont

Pelycosaur

Early Triassic ~250 mya

Late Paleozoic ~300 mya

COMPARATIVE PRIMATE ANATOMY OF THE ELBOW REGION Much of what follows is taken from the detailed studies of Rose.20,21 The humeral trochlea may be cylindrical, conical, or trochleariform in nonhuman primates.21 The trochlea is conical in some prosimians, but a cylindrical trochlea seems to be the most common shape and is observed in most prosimians and New World monkeys. The trochlea is also cylindrical in most Old World monkeys but with a pronounced medial flange or keel that is best developed anterodistally (Fig. 1-2). Only in apes and humans is the trochlea truly trochleariform, possessing medial and lateral ridges all around the trochlear margins, which contribute to the stability of the ulnohumeral joint, substituting for the radiohumeral joint, which is freed for pronosupination throughout the flexion range.11,20 In most species, the articular surface of

The major evolutionary stages in the development of the elbow joint from pelycosaurs to advanced mammals. The distal ends of the humeri are shown on the left, and the corresponding radius and ulna are on the right. The form of the pelycosaur elbow was designed to maximize stability. Subsequent evolutionary stages show accommodations to increasing mobility. (Adapted from Jenkins, F. A. Jr.: The functional anatomy and evolution of the mammalian humeroulnar articulation. Am. J. Anat. 137:281, 1973.)

the trochlea expands posteriorly to the area behind the capitellum. In larger monkeys, the lateral edge of the posterior trochlear surface projects to form a keel that extends up the lateral wall of the olecranon fossa (see Fig. 1-2). In hominoids, this keel is a continuation of the lateral trochlear ridge and helps form a sharp lateral margin of the olecranon fossa, providing resistance to varus and internal rotation in extension.20.21 The trochlear notch of the ulna generally mirrors the shape of the humeral trochlea. In humans and apes, the notch has medial and lateral surfaces separated by a ridge that articulates with the trochlear groove (Fig. 1-3).20,21 The differences seen in the configuration of the humeroulnar joint across primate species reflect contrasting requirements for stabilization with different forms of limb use. In most monkeys, the humeroulnar joint is in its most stable configuration in a partially

Chapter 1 Phylogeny

BABOON

CHIMPANZEE

5

HUMAN

Anterior

FIGURE 1-2

Lateral trochlear ridge

Zona conoidea

Distal

Posterior keel

Posterior

BABOON

CHIMPANZEE

HUMAN

Long olecranon process

Heavily buttressed coronoid process

FIGURE 1-3

Proximal ulnae of a baboon, a chimpanzee, and a human. The trochlear notch is wider in the chimpanzee and the human and displays a prominent ridge for articulation with the trochlear groove. In addition, the radial notch faces laterally in the chimp and human, unlike in the baboon, in which it faces more anteriorly.

Distal humeri of a baboon, a chimpanzee, and a human from anterior, distal, and posterior aspects. The lateral trochlear ridge is well developed in both the human and the chimpanzee but is largely nonexistent in the baboon. The baboon humerus displays prominent flanges anteromedially and posterolaterally. The lateral epicondyle is placed higher in the chimpanzee than in the human and displays a more strongly developed supracondylar crest.

flexed position owing to the development of the medial trochlear keel anterodistally and the lateral keel posteriorly.20 It is not surprising that this position of maximum stability is the one assumed by the forelimb during the weight-bearing phase of quadrupedal locomotion. The anterior orientation of the trochlear notch is a direct adaptation to weight bearing with a partially flexed limb. However, such an orientation does limit elbow extension to some degree. The great apes (chimpanzees, gorillas, and orangutans) and the lesser apes (gibbons) move about in a much less stereotypical fashion than do monkeys. To accommodate this more varied form of limb use, the hominoid humeroulnar joint, with its deeply socketed articular surfaces and well-developed medial and lateral trochlear ridges all around the joint margins, is designed to provide maximum stability throughout the flexionextension range.20-22 The use of overhead suspensory postures and locomotion in apes has led to the

6

Part I Fundamentals and General Considerations

evolution of the capacity for complete elbow extension. Apes even keep their elbows extended during quadrupedal locomotion. The ideal joint configuration for resistance of transarticular stress with fully extended elbows during quadrupedal postures would be to have a trochlear notch that was proximally directed. It could then act as a cradle to support the humerus during locomotion. However, a proximal orientation of the trochlear notch would severely limit elbow flexion by impingement of the coronoid process within its fossa. The anteroproximal orientation of the trochlear notch in apes thus represents a compromise that safely supports the humerus on the ulna in extended elbow positions during locomotion without unduly sacrificing elbow flexion.1 On the lateral side of the elbow, the articular surface on the capitellum extends farther posteriorly in apes and humans than in monkeys, allowing the radius to move with the ulna into full extension of the elbow. In addition, the capitellum of apes and humans is uniformly rounded, reflecting versatility rather than stereotypy in forelimb usage (Fig. 1-4). The gutter-like region between the trochlea and capitellum—the zona conoidea—is a relatively flat plane that terminates distally in most monkeys. In the hominoids, it continues posteriorly (see Fig. 1-1).20,21 The zona conoidea articulates with the bevel of the radial head, and differences in its configuration reflect differences in the shape of the radial head. The radial head of hominoid primates is nearly circular, and the peripheral rim is symmetrical and beveled all around the circumference of the radial head for articulation with the zona conoidea (Fig. 1-5). This con-

BABOON

CHIMPANZEE

HUMAN

figuration provides good contact to resist dislocation of the radial head from the humerus under the varied loading regimes experienced by the hominoid elbow and can stabilize the radial head in all positions of pronosupination.20,21 In most monkeys and prosimians, the radial head is ovoid and the proximal radioulnar joint articulation is restricted to the anterior and medial surfaces; as a result, the joint becomes close packed for stability in pronation (Fig. 1-6). In apes and humans, on the other hand, this articular surface extends almost all the way around the head, implying a greater range of pronosupination.20 The radial notch of the ulna in most monkeys and prosimians faces either anterolaterally or directly anteriorly, whereas in hominoids, it faces more laterally.20,21 The configuration observed in apes and humans emphasizes a broad range of pronosupination with a nearly equal degree of stability in all positions.20,21 In general terms, most of the differences in elbow joint morphology between quadrupedal monkeys and

Supination

Pronation

Monkey

Ape

Flaring supracondylar crest High lateral epicondyle

FIGURE 1-4

Low and weakly developed lateral epicondyle

Distal humeri of a baboon, a chimpanzee, and a human from the lateral aspect. The articular surface of the capitellum extends further onto the posterior surface of the bone (small arrows) in humans and chimpanzees to permit full extension at the humeroradial joint.

L

FIGURE 1-5

M

Diagrammatic anterior views of the right humeroradial joints of a monkey and an ape in the prone and supine positions. In the monkey, the lateral bevel of the radial head comes into maximum congruence with the zona conoidea (hatched area) in the prone position, thereby creating a maximally stable joint configuration. In the ape, the rim of the more symmetrical radial head maintains good contact with the recessed zona conoidea in all positions of pronosupination. This contributes to a configuration emphasizing universal stability at the ape elbow rather than a position of particular stability, as seen in the monkey. (Adapted from Rose, M. D.: Another look at the anthropoid elbow. J. Hum. Evol. 17:193, 1988.)

Chapter 1 Phylogeny

Supination

7

Pronation

Monkey

Lateral lip

Ape cg

L

M

FIGURE 1-6

Diagrammatic view of the radioulnar joint in pronation and supination in a monkey and an ape. A section through the radius and ulna in the region of the radial notch is superimposed on an outline of the distal humerus. In the monkey, the radial notch faces anterolaterally, whereas in the ape, it faces more directly laterally. The radial head of the monkey with its lateral lip comes into maximum congruence in the pronated position, conferring maximum stability in this position. The ape radioulnar joint, on the other hand, displays no such position of particular stability and instead emphasizes mobility. (Adapted from Rose, M. D.: Another look at the anthropoid elbow. J. Hum. Evol. 17:193, 1988.)

the apes can be related to the development of a position of particular stability in monkeys versus more universal stability in apes. A few additional features of the human elbow are shared with apes, such as a more distal biceps tuberosity (longer radial neck) relative to their body size.21 In apes, this is probably related to the demands for powerful elbow flexion to raise the center of mass of the body during climbing and suspensory postures and locomotion. Although the radial tuberosity faces more or less anteriorly in most primates, it faces more medially in apes and humans, reflecting their greater range of pronosupination.17 Extreme supination is an important component of suspensory locomotion in apes, and the medially placed tuberosity provides maximum supination torque near full supination.14,30 Apes and humans share a relatively short lever arm for triceps compared with that of most other primates, which is generally attributed to the demands for rapid elbow extension during suspensory locomotion. Finally, apes and humans are distinguished from other primate species in possess-

FIGURE 1-7

Frontal view of an arm-swinging gibbon showing the skeletal structure of the forelimb. The carrying angle of the elbow brings the center of mass (i.e., center of gravity [cg]) more nearly directly under the supporting hand. (Adapted from Sarmiento, E. E.: Functional Differences in the Skeleton of Wild and Captive Orang-Utans and Their Adaptive Significance. Ph.D. Thesis, New York University, 1985.)

ing a biomechanical carrying angle at the elbow. Sarmiento22 has argued that the evolution of a carrying angle in apes is related to the need to bring the center of mass of the body beneath the supporting hand during suspensory locomotion in a manner similar to that in which the valgus knee of humans brings the foot nearer the center of mass of the body during the single limb support phase of walking (Fig. 1-7). All of these features have been retained in humans because of their continued advantages for tool use and other behaviors. Powerful flexion is clearly important. The continued importance of the carrying angle is perhaps less obvious, but one advantage that it does offer is that flexion of the elbow is accompanied by adduction of the forearm, thus bringing the hands more in front of the body, where most manipulatory activities are undertaken. The morphology of the modern human elbow is not identical to that of the ape elbow, however. In some cases, the differences are simply a matter of degree. For example, although both apes and humans are

8

Part I Fundamentals and General Considerations

distinguished from other primates in the medial orientation of the radial tuberosity, it is more extreme in position in the ape; in the human it is typically slightly anterior to true medial. In addition, although the olecranon is short in both humans and apes compared with most monkeys, it is slightly longer in humans than in apes and also shaped to maintain this length throughout the range of flexion—both of which are advantageous for powerful manipulatory activities.4 Other differences between the elbow morphology of humans and that of apes can be related to the fact that the human forelimb has no role in locomotion. These differences include a less robust coronoid process and a relatively narrower, proximally oriented trochlear notch in humans, indicating relative stability in flexion rather than the need to support the weight of the body during quadrupedal locomotion in extension.1,13 Humans possess a smaller and more distally placed lateral epicondyle and a less well-developed supracondylar crest than is seen in the apes, reflecting diminished leverage of the wrist extensors and brachioradialis.23-25 Humans have no bowing of the ulna that is related to enhancing the leverage of the forearm pronators and supinators in apes.1 Finally, a diminution in the prominence of the trochlear ridges and steep lateral margin of the olecranon fossa in humans can be related to the overall reduction in stresses at the human elbow and the concomitant relaxation on the demands for strong stabilization in all positions.20,21 When exactly did the basic pattern for the hominoid elbow arise, and how old is the morphology of the modern human elbow? For answers to these questions we must turn to the fossil record.

FOSSIL EVIDENCE Dendropithecus macinnesi, Limnopithecus legetet, and Proconsul heseloni (all from Africa) are among the earliest known hominoid species dated to the early part of the Miocene epoch (23 to 16 mya) for which postcranial material is known. Overall, the distal humeri of the first two of these forms resemble generalized New World monkeys such as Cebus (capuchin monkeys). The trochlea does not display a prominent lateral ridge, and the zona conoidea is relatively flat. The trochlear notch faces anteriorly, and the head of the radius is oval in outline with a well-developed lateral lip. These features generally are considered to be primitive for higher primates (monkeys, apes, and humans).8,9,20 P. heseloni, on the other hand, does display some features characteristic of extant hominoids. It has a globular capitellum, well-developed medial and lateral trochlear ridges, and a deep zona conoidea forming the medial wall of a recessed gutter between the capitellum and

trochlea.20 In general, the elbow region of Proconsul resembles that of extant hominoids in features related to general stability and range of pronosupination; yet full pronation remained a position of particular stability.20 The limited fossil material that is available from the late Miocene epoch (16 to 5 mya) suggests that many hominoid species, including members of the genera Dryopithecus (from Europe), Sivapithecus (from Europe and Asia), and Oreopithecus (from Europe), displayed the features characteristic of the modern hominoid elbow. Although it is possible that these features arose in parallel in different genera, the more parsimonious explanation is that they inherited this morphology from an early to middle Miocene common ancestor, possibly similar to P. heseloni.16,29,31 Assuming that the characteristic features of the hominoid elbow are shared derived traits, that is, traits inherited from a single common ancestor, we can say that the elbow morphology of modern apes and humans can be dated to roughly 15 to 20 mya. The majority of paleoanthropologists agree that humans are most closely related to the African apes (chimpanzees and gorillas) and that the two lineages arose in the late Miocene or earliest Pliocene period (between 10 and 4 mya).8 The earliest known fossils of the human lineage (hominids) date from the early Pliocene era, approximately 4 to 5 mya. There are three genera of these earliest hominids currently recognized, Ardipithecus, Paranthropus, and Australopithecus. The latter is the best known and most widespread genus, and includes the famous “Lucy” skeleton from Hadar, Ethiopia (A. afarensis).5,12 The genus Homo, to which our own species belongs, first appeared about 2.5 to 2 mya in East Africa with its earliest member species, H. habilis. All of the hominids from the Pliocene period were bipedal, although some probably spent significant time climbing trees.23-26,28 The development of bipedalism freed the upper extremity from the requirements of locomotion, placing greater emphasis on increasing mobility. The ability to supinate and pronate was an immense advantage to hominids in caring for their young, defending themselves, and gathering food. It was also critical in efficient tool handling, which developed approximately 2 mya, at about the same time as H. habilis, although there is debate about which species of early hominid was responsible for making them.27 Several distal humeri are known from these early hominid species. All of the early hominid distal humeri lack the steep lateral margin of the olecranon fossa that is characteristic of chimpanzees and gorillas. However, they do show a considerable amount of morphologic variation in other characteristics (Fig. 1-8). On the basis of the contour of the distal end of the humeral shaft,

Chapter 1 Phylogeny

9

PHYLOGENY

AL 288-1m

KNM-ER 739

Gombore IB 7594

FIGURE 1-8

Distal humeri of Plio-Pleistocene hominids. Gombore IB 7594 represents early Homo on the basis of the moderate development of the lateral trochlear ridge and low position of the lateral epicondyle. AL 288-1m (part of the “Lucy” skeleton, Australopithecus afarensis) displays a more prominent lateral trochlear ridge, a recessed, gutter-like zona conoidea, a high position of the lateral epicondyle, and a well-developed supracondylar crest. Therefore, it resembles living apes in many features of its elbow morphology. KNM-ER 739 has been attributed to Paranthropus boisei and, like AL 288-1m, has a lateral epicondyle that is positioned above the articular surfaces. However, it is more like Homo, with the moderate development of the lateral trochlear ridge.

the placement of the epicondyles, and the configuration of the articular surface, the fossil distal humeri have been divided into two groups. The first group is characterized by a weakly projecting lateral epicondyle that is placed low, at about the level of the capitellum, and by a moderately developed lateral trochlear ridge.23,24 These are features shared with modern humans, and consequently, this group generally is referred to as early Homo. The second group includes the Australopithecus and Paranthropus species and is characterized by a well-developed lateral epicondyle that is high relative to the capitellum. These features are similar to those of modern apes. A number of fragments of early hominid proximal radii have been recovered representing each of the currently recognized species. The proximal radial fragments that have been attributed to early Homo display a much narrower bevel around the capitellar fovea than that of the modern apes and the earlier hominin group. This provides for articulation with a more shallow zona conoidea and a more vertical and uniformly wide surface on the side of the head for articulation with the ulna favoring pronosupination over stability. Other primitive hominoid features include thick cortices, a relatively long and angulated radial neck (lower neck shaft angle), and a more anteromedially (rather than medially) placed biceps tuberosity. Many of these features are still present in a small percentage of modern humans, limiting the functional conclusions that can be drawn and suggesting a mosaic pattern of evolution.18,19 Some early hominid ulnae that have been recovered appear to retain many primitive features including a

longer more curved shaft, greater mediolateral width proximally, and a nonprominent interosseous border.1,2,10 However, early human ulnae attributed to the genus Homo are similar to those of modern humans in having a prominent interosseous border, a supinator crest, and a well-marked hollow for the play of the tuberosity of the radius.6,7,15 It appears, therefore, that many of the characteristics that distinguish the human elbow from that of the ape can be found in the earliest members of our genus. In overview, the combination of comparative anatomy and the fossil record indicates that the modern human elbow owes its beginnings to our hominoid ancestry. Current evidence suggests that many of the characteristic features of the human distal humerus and proximal radius and ulna can be projected back approximately 15 to 20 mya to a common ancestor of extant apes and humans. Functional analysis suggests that this morphologic structure arose in hominoid primates in response to the need for stabilization throughout the flexionextension and pronosupination ranges of motion to permit a more versatile form of forelimb use. This morphology was still largely intact following the evolution of upright posture and bipedal locomotion in the earliest known hominids. However, as the forelimb became less and less involved in locomotion, the hominid elbow underwent additional modifications, relaxing some of the emphasis on stabilization and increasing performance throughout the range of movement. The fossil record indicates that the distinct form of the modern human elbow probably first appeared about 2 mya in

10

Part I Fundamentals and General Considerations

our ancestor H. habilis. This morphology has changed only subtly during all subsequent stages of human evolution.

Acknowledgments SGL would like to thank Jack Stern and John Fleagle for helpful comments on earlier versions of this chapter, and Luci Betti-Nash for the preparation of figures.

The references in this chapter which suggest the evolution of the human from a lower form are not accepted by and do not express the views of all of the contributors of this book.

References 1. Aiello, L. C., and Dean, M. C.: An Introduction to Human Evolutionary Anatomy. London, Academic Press, 1990. 2. Churchill, S. E., Pearson, O. M., Grine, F. E., Trinkaus E., and Holliday T. W.: Morphological affinities of the proximal ulna from Klasies River main site: archaic or modern? J. Hum. Evol. 31:213, 1996 3. Conroy, G. C.: Primate Evolution. New York, W. W. Norton & Co., 1990. 4. Drapeau, M. S.: Functional anatomy of the olecranon process in hominoids and Plio-Pleistocene hominins. Am. J. Phys. Anthropol. 124:297, 2004 5. Drapeau, M. S., Ward, C. V., Kimbel, W. H., Johanson, D. C., and Rak, Y.: Associated cranial and forelimb remains attributed to Australopithecus afarensis from Hadar, Ethiopia. J. Hum. Evol. 48:593, 2005. 6. Day, M. H.: Functional interpretations of the morphology of postcranial remains of early African hominids. In Jolly, C. J. (ed): Early Hominids of Africa. London, Duckworth, 1978, p. 311. 7. Day, M. H., and Leakey, R. E. F.: New evidence for the genus Homo from East Rudolf, Kenya III. Am. J. Phys. Anthropol. 39:367, 1974. 8. Fleagle, J. G.: Primate Adaptation and Evolution, 2nd ed. New York, Academic Press, 1999. 9. Harrison, T.: The phylogenetic relationships of the early catarrhine primates: a review of the current evidence. J. Hum. Evol. 16:41, 1987. 10. Howell, F. C., and Wood, B. A.: Early hominid ulna from the Omo Basin, Ethiopia. Nature 249:174, 1974. 11. Jenkins, F. A. Jr.: The functional anatomy and evolution of the mammalian humeroulnar articulation. Am. J. Anat. 137:281, 1973. 12. Johanson, D. C., Lovejoy, C. O., Kimbel, W. H., White, T. D., Ward, S. C., Bush, M. E., Latimer, B. M., and Coppens, Y.: Morphology of the Pliocene partial hominid skeleton (A.L. 288-1) from the Hadar Formation, Ethiopia. Am. J. Phys. Anthropol. 57:403, 1982.

13. Knussmann, R.: Humerus, Ulna and Radius der Simiae. Bibliotheca Primatologica, Vol. 5. Basel, S. Karger, 1967. 14. Larson, S. G.: Subscapularis function in gibbons and chimpanzees: implications for interpretation of humeral head torsion in hominoids. Am. J. Phys. Anthropol. 76:449, 1988. 15. Leakey, R. E. F.: Further evidence of lower Pleistocene hominids from East Rudolf, Northern Kenya. Nature 237:264, 1972. 16. Martin, L., and Andrews, P.: Cladistic relationships of extant and fossil hominoids. J. Hum. Evol. 16:101, 1987. 17. O’Connor, B. L., and Rarey, K. E.: Normal amplitudes of radioulnar pronation and supination in several genera of anthropoid primates. Am. J. Phys. Anthropol. 51:39, 1979. 18. Patel, B. A. The hominoid proximal radius: re-interpreting locomotor behaviors in early hominins. J. Hum. Evol. 48:415, 2005. 19. Pearson, O. M., and Grine, F. E.: Re-analysis of the hominid radii from Cave of Hearths and Klasies River Mouth, South Africa. J. Hum. Evol. 32:577, 1997. 20. Rose, M. D.: Another look at the anthropoid elbow. J. Hum. Evol. 17:193, 1988. 21. Rose, M. D.: Functional anatomy of the elbow and forearm in primates. In Gebo, D. (ed.): Postcranial Adaptation in Nonhuman Primates. DeKalb, IL, Northern Illinois Press, 1993, p. 70. 22. Sarmiento, E. E.: Functional Differences in the Skeleton of Wild and Captive Orang-Utans and Their Adaptive Significance. Ph.D. Thesis, New York University, 1985. 23. Senut, B.: Outlines of the distal humerus in hominoid primates: application to some Plio-Pleistocene hominids. In Chiarelli A. B., and Corruccini, R. (eds.): Primate Evolutionary Biology. Berlin, Springer Verlag, 1981, p. 81. 24. Senut, B.: Humeral outlines in some hominoid primates and in Plio-Pleistocene hominids. Am. J. Phys. Anthropol. 56:275, 1981. 25. Senut, B., and Tardieu, C.: Functional aspects of PlioPleistocene hominid limb bones: implications for taxonomy and phylogeny. In Delson, E. (ed.): Ancestors: The Hard Evidence. New York, A. Liss, 1985, p. 193. 26. Stern, J. T. Jr., and Susman, R. L.: The locomotor anatomy of Australopithecus afarensis. Am. J. Phys. Anthropol. 60:279, 1983. 27. Susman, R. L.: Fossil evidence for early hominid tool use. Science 265:1570, 1994. 28. Susman, R. L., Stern, J. T. Jr., and Jungers, W. L.: Arboreality and bipedality in Hadar hominids. Folia Primatol. 43:113, 1984. 29. Szalay, F. S., and Delson, E.: Evolutionary History of the Primates. New York, Academic Press, 1979. 30. Trinkaus, E, and Churchill, S. E. Neandertal radial tuberosity orientation. Am. J. Phys. Anthropol. 75:15, 1988. 31. Ward, C. V., Walker, A., and Teaford, M. F.: Proconsul did not have a tail. J. Hum. Evol. 21:215, 1991.

Chapter 2 Anatomy of the Elbow Joint

CHAPTER

2

Anatomy of the Elbow Joint Bernard F. Morrey

11

neus, extensor carpi ulnaris, extensor digitorum quinti, and extensor digitorum communis. Dermal innervation about the proximal elbow is rather variable being provided by the lower lateral cutaneous (C5, C6) and medial cutaneous (radial nerve, C8, T1 and T2) nerves of the arm. The forearm skin is innervated by the medial (C8, T1), lateral (musculocutaneous, C5, C6), and posterior (radial nerve, C6-8) cutaneous nerves of the forearm (Fig. 2-4).

OSTEOLOGY This chapter discusses the normal anatomy of the elbow region. Abnormal and surgical anatomy is addressed in subsequent chapters of this book dealing with the pertinent condition.

TOPICAL ANATOMY AND GENERAL SURVEY The contours of the biceps muscle and antecubital fossa are easily observed anteriorly. Laterally, the avascular interval between the brachioradialis and the triceps, the so-called column, is an important palpable landmark for surgical exposures (Fig. 2-1). Laterally, the tip of the olecranon, the lateral epicondyle, and the radial head also form an equilateral triangle and provide an important landmark for joint aspiration and for elbow arthroscopy (see Chapters 37 and 77). The flexion crease of the elbow is in line with the medial and lateral epicondyles and thus is actually 1 to 2 cm proximal to the joint line when the elbow is extended (Fig. 2-2). The inverted triangular depression on the anterior aspect of the extremity distal to the epicondyles is called the cubital (or antecubital) fossa. The superficial cephalic and basilic veins are the most prominent superficial major contributions of the anterior venous system and communicate by way of the median cephalic and median basilic veins to form an “M” pattern over the cubital fossa (Fig. 2-3). The extensor forearm musculature originates from the lateral epicondyle and was termed the mobile wad by Henry.37 This forms the lateral margin of the antecubital fossa and the lateral contour of the forearm and comprises the brachioradialis and the extensor carpi radialis longus and brevis muscles. The muscles comprising the contour of the medial anterior forearm include the pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris. Henry has demonstrated that their relationship and location can be approximated by placing the opposing thumb and the index, long, and ring fingers over the anterior medial forearm. The dorsum of the forearm is contoured by the lateral extensor musculature, consisting of the anco-

HUMERUS The distal humerus consists of an arch formed by two condyles that contain the articular surfaces of the trochlea and capitellum (Fig. 2-5). Medial to the trochlea, the prominent medial epicondyle serves as a source of attachment of the medial ulnar collateral ligament and the flexor-pronator group of muscles. Laterally, the lateral epicondyle is located just proximal to the capitellum and is much less prominent than the medial epicondyle. The lateral ulnar collateral ligament and the supinator-extensor muscle group originate from the flat, irregular surface of the lateral epicondyle. Anteriorly, the radial and coronoid fossae accommodate the radial head and coronoid process during flexion. Posteriorly, the olecranon fossa receives the tip of the olecranon. In about 90% of individuals,86 a thin membrane of bone separates the olecranon and coronoid fossae (Fig. 2-6). The medial supracondylar column is smaller than the lateral and explains the vulnerability of the medial column to fracture with trauma and some surgical procedures.56 The posterior aspect of the lateral supracondylar column is flat, allowing ease of application of contoured plates (see Chapter 22). The prominent lateral supracondylar ridge serves as attachment for the brachioradialis and extensor carpi radialis longus muscles anteriorly and for the triceps posteriorly. It is also an important landmark for many lateral surgical approaches especially for the “column procedure” (see Chapters 7 and 32). Proximal to the medial epicondyle, about 5 to 7 cm along the medial intramuscular septum, a supracondylar process is observed in 1% to 3% of individuals45,49,81 (Fig. 2-7). A fibrous band termed the ligament of Strothers may originate from this process and attach to the medial epicondyle.38 When present, this spur serves as an anomalous insertion of the coracobrachialis muscle and an origin of the pronator teres muscle.34 Various pathologic processes have been associated with the supracondylar process, including fracture45 and median4 and ulnar nerve38 entrapment (see Chapter 80).

12

Part I Fundamentals and General Considerations

RADIUS

FIGURE 2-1

The palpable landmarks of the tip of the olecranon and the medial and lateral epicondyles form an inverted triangle posteriorly when the elbow is flexed 90 degrees but are colinear when the elbow is fully extended. (Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)

The radial head defines the proximal radius and articulates with the capitellum. It exhibits a cylindrical shape with a depression in the midportion to accommodate the capitellum. The disc-shaped head is secured to the ulna by the annular ligament (Fig. 2-8). Distal to the radial head, the bone tapers to form the radial neck, which, along with the head, is vulnerable to fracture.83 The radial tuberosity marks the distal aspect of the neck and has two distinct parts. The anterior surface is covered by a bicipitoradial bursa protecting the biceps tendon during full pronation (Fig. 2-9). However, it is the rough posterior aspect that provides the site of attachment of the biceps tendon. During full pronation the tuberosity is in a dorsal position and allows repair of a ruptured biceps tendon through a posterior approach12 (see Chapter 34) and is helpful to determine axial alignment of proximal radial fractures.26

ULNA The proximal ulna provides the greater sigmoid notch (incisura semilunaris), which serves as the major articulation of the elbow that is responsible for its inherent

FIGURE 2-2

A line placed over the flexion crease (A) is actually situated about 1 cm above the elbow joint line (B).

Chapter 2 Anatomy of the Elbow Joint

13

Fascia brachii V. basilica humeri

V. cephalica humeri

N. cutaneus M. biceps brachii M. pronator teres Lacertus fibrosus M. flexor carpi radialis V. mediana cephalica V. mediana basilica N. cutaneous antibrachii lateralis

M. pronator teres

V. basilica antibrachii

V. mediana antibrachii V. cephalica antibrachii Ramus anastomoticus

M. flexor carpi radialis

Fascia antibrachii

FIGURE 2-3

The superficial venous pattern of the anterior aspect of the elbow demonstrates a rather characteristic inverted M pattern formed by the median cephalic and median basilic veins. (Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)

Lateral supraclavicular (C. 3 and 4) Axillary (C. 5 and 6)

Lateral supraclavicular (C. 3 and 4)

Medial cutaneous of arm (T. 1 and 2) and intercostobrachial (T. 2)

Medial cutaneous of arm and intercostobrachial (T. 1 and 2)

Lower lateral cutaneous of arm (radial, C. 5 and 6) Lateral cutaneous of forearm (musculocutaneous, C. 5 and 6) Radial (C. 7 and 8)

Axillary (C. 5 and 6) Posterior cutaneous of arm (radial) Lower lateral cutaneous of arm (radial)

Medial cutaneous of forearm Medial cutaneous of forearm (C. 8, T. 1)

Ulnar (C. 7 and 8)

Radial

Posterior cutaneous of forearm (radial) Lateral cutaneous of forearm (musculocutaneous)

Median (C. 6, 7 and 8) Ulnar

A

FIGURE 2-4

B

Median

Typical distribution of the cutaneous nerves of the anterior (A) and posterior (B) aspects of the upper limb. (Redrawn from Cunningham, D. J.: In G. J. Romanes (ed.): Textbook of Anatomy, 12th ed. New York, Oxford University Press, 1981.)

14

Part I Fundamentals and General Considerations

Groove for the radial n.

Lateral supracondylar ridge

Lateral epicondyle

Coronoid fossa Medial epicondyle

Radial fossa Capitellum

FIGURE 2-5

The bony landmarks of the anterior aspect of the distal humerus.

Trochlea

Groove for the radial n.

Lateral supracondylar ridge Medial supracondylar column Lateral supracondylar column Olecranon fossa

FIGURE 2-6 Sulcus for ulnar n.

The prominent medial and lateral supracondylar bony columns as well as other landmarks of the posterior aspect of the distal humerus.

Chapter 2 Anatomy of the Elbow Joint

Radial head

15

Articular margin

Radial neck

Tuberosity

FIGURE 2-8

Proximal aspect of the radius demonstrating the articular margin for articulation with the olecranon, the radial neck, and tuberosity.

FIGURE 2-7

Typical supracondylar process located approximately 5 cm proximal to the medial epicondyle with its characteristic configuration.

Radiohumeral B.

Supinator B. Cubital interosseus B.

Bicipital radial B.

FIGURE 2-9

A deep view of the anterior aspect of the joint revealing the submuscular bursa present about the elbow joint.

16

Part I Fundamentals and General Considerations

Guiding ridge

Greater sigmoid notch Coronoid Radial notch

Transverse groove of greater sigmoid notch Tubercle

Supinator crest and tuberosity

Olecranon

Ulnar tuberosity

B FIGURE 2-10

A stability (Fig. 2-10). The cortical surface of the coronoid process serves as the site of insertion of the brachialis muscle and of the oblique cord. Medially the sublime tubercle serves as insertion site of the medial ulnar collateral ligament. The triceps tendon attaches to the posterior aspect of the olecranon process. On the lateral aspect of the coronoid process, the lesser semilunar or radial notch articulates with the radial head and is oriented roughly perpendicular to the long axis of the bone. Distal to this the supinator crest serves as attachment to the supinator muscle, a tuberosity occurs on this crest, which is the site of insertion of the lateral ulnar collateral ligament.52,56,66

ELBOW JOINT STRUCTURE ARTICULATION The elbow joint articulation is classified as a trochoginglymoid joint.77 The ulnohumeral joint resembles a hinge (ginglymus), allowing flexion and extension. The radiohumeral and proximal radioulnar joint allows axial rotation or a pivoting (trochoid) type of motion.

Humerus The trochlea is the hyperboloid, pulley-like surface that articulates with the semilunar notch of the ulna covered by articular cartilage through an arc of 300 degrees42,73,77 (Fig. 2-11). The medial contour is larger and projects more distally than does the lateral portion of the trochlea (Fig. 2-12). The two surfaces are separated by a groove that courses in a helical manner from an anterolateral to a posteromedial direction. The capitellum is almost spheroidal in shape and is covered with hyaline cartilage, which is about 2 mm thick anteriorly. A groove separates the capitellum from the trochlea, and the rim of the radial head articulates with this groove throughout the arc of flexion and during pronation and supination.

A, Anterior aspect of the proximal ulna demonstrating the greater sigmoid fossa with the central groove. B, Lateral view with landmarks.

In the lateral plane, the orientation of the articular surface of the distal humerus is rotated anteriorly about 30 degrees with respect to the long axis of the humerus (Fig. 2-13). The center of the concentric arc formed by the trochlea and capitellum is on a line that is coplanar to the anterior distal cortex of the humerus.58 In the transverse plane, the articular surface and axis of rotation is rotated inward approximately 5 degrees (Fig. 2-14), and in the frontal plane, it is tilted approximately 6 degrees in valgus43,47,80 (Fig. 2-15).

Proximal Radius Hyaline cartilage covers the depression of the radial head, which has an angular arc of about 40 degrees,77 as well as approximately 240 degrees of articular cartilage that articulates with the ulna, hence approximately 120 degrees of the radial circumference is not articular and amenable to open reduction internal fixation (ORIF) for fracture16 (Fig. 2-16). The lesser sigmoid fossa forms an arc of approximately 60 to 80 degrees,42,77 leaving an excursion of about 180 degrees for pronation and supination. The anterolateral third of the circumference of the radial head is void of cartilage. This part of the radial head lacks subchondral bone and thus is not as strong as the part that supports the articular cartilage; this part has been demonstrated to be the portion most often fractured.83 The head and neck are not co-linear with the rest of the bone and form an angle of approximately 15 degrees, with the shaft of the radius directed away from the radial tuberosity28 (Fig. 2-17).

Proximal Ulna In most individuals, a transverse portion of nonarticular cartilage divides the greater sigmoid notch into an anterior portion comprising the coronoid and the posterior olecranon (Fig. 2-18). In the lateral plane, the sigmoid notch forms an arc of about 190 degrees.74 The contour is not a true hemicircle but rather is elipsoid. This explains the articular void in the midportion.85

Chapter 2 Anatomy of the Elbow Joint

Corpus humeri

M. brachialis M. biceps brachii Lig. anterius Fat pad

M. triceps brachii Lig. posterius

M. pronator teres

Synchondrosis epiphyseos

N. medianus A. et V. brachialis

Trochlea

M. flexor digitorum sublimis Processus coronoideus M. flexor digitorum profundus

Pars fibrosa Pars synovialis Bursa subtendinea olecrani Cavum articulare

Capsula articularis

Incisura semilunaris ulnae Ulna

Olecranon Synchondrosis epiphyseos ulnae Bursa subcutanea olecrani

M. anconaeus

Trochleocapitellar groove

Tubercle of trochlea

17

FIGURE 2-11

Sagittal section through the elbow region, demonstrating the high degree of congruity. (Redrawn from Anson, B. J., and McVay, C. B.: Surgical Anatomy, Vol. 2, 5th ed. Philadelphia, W. B. Saunders Co., 1971.)

Trochlear groove

Medial lip Lateral lip

FIGURE 2-12

Axial view of the distal humerus shows the isometric trochlea as well as the anterior position of the capitellum. The trochlear capitellar groove separates the trochlea from the capitellum.

The orientation of the articulation is oriented approximately 30 degrees posterior to the long axis of the bone (Fig. 2-19). This matches the 30 degrees anterior angulation of the distal humerus, providing stability in full extension (see Chapter 3). In the frontal plane, the shaft is angulated from about 1 to 6 degrees43,47,73 lateral to the articulation (Fig. 2-20). This angle contributes, in part, to the variation of the carrying angle, which is discussed in Chapter 3. The lesser sigmoid notch consists of a depression with an arc of about 70 degrees and is situated just distal to the lateral aspect of the coronoid and articulates with the radial head.

30˚

FIGURE 2-13

Lateral view of the humerus shows the 30degree anterior rotation of the articular condyles with respect to the long axis of the humerus.

CARRYING ANGLE The so-called carrying angle is the angle formed by the long axes of the humerus and the ulna with the elbow fully extended (Fig. 2-21). In men, the mean carrying angle is 11 to 14 degrees, and in women, it is 13 to 16 degrees.3,43,69 Furthermore, the carrying angle is approxi-

Part I Fundamentals and General Considerations

18

Olecranon Articular circumference 5˚

Head of radius Trochlear notch of ulna

FIGURE 2-14

Axial view of the distal humerus demonstrates the 5- to 7-degree internal rotation of the articulation in reference to the line connecting the midportions of the epicondyles.

Coronoid process

Annular ligament Tuberosity of radius

Radius

Ulna

FIGURE 2-16

Hyaline cartilage covers approximately 240 degrees of the outside circumference of the radial head, allowing its articulation with the proximal ulna at the radial notch of the ulna. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

15˚

6˚

FIGURE 2-15

There is approximately a 6- to 8-degree valgus tilt of the distal humeral articulation with respect to the long axis of the humerus.

mately 1 degree greater in the dominant than nondominant side.88

JOINT CAPSULE The anterior capsule inserts proximally above the coronoid and radial fossae (Fig. 2-22). Distally, the capsule attaches to the anterior margin of the coronoid medially as well as to the annular ligament laterally. Posteriorly, the capsule attaches just above the olecranon fossa, distally along the supracondylar bony columns. Distally, attachment is along the medial and lateral articular margin of the sigmoid notch. The greatest capacity of

FIGURE 2-17

The neck of the radius makes an angle of approximately 15 degrees with the long axis of the proximal radius.

the elbow occurs at about 80 degrees of flexion40,70 and is 25 to 30 mL.70 The anterior capsule is normally a thin transparent structure but significant strength is provided by transverse and obliquely directed fibrous bands23,56 (Fig. 2-23).

Chapter 2 Anatomy of the Elbow Joint

19

4˚

3

63

32

2

FIGURE 2-18

The relative percentage of hyaline cartilage distribution at the proximal ulna. (Redrawn from Tillmann, B.: A Contribution to the Function Morphology of Articular Surfaces. Translated by G. Konorza. Stuttgart, George Thieme, Publishers; P. S. G. Publishing Co., Littleton, Mass., 1978.)

30˚

FIGURE 2-19

The greater sigmoid notch opens posteriorly with respect to the long axis of the ulna. This matches the 30-degree anterior rotation of the distal humerus, as shown in Figure 2-13.

The anterior structure is, of course, taut in extension but becomes lax in flexion. The joint capsule is innervated by highly variable branches from all major nerves crossing the joint, including the contribution from the musculoskeletal nerve (Fig. 2-24).

LIGAMENTS The collateral ligaments of the elbow are formed by specialized thickenings of the medial and lateral capsules.

FIGURE 2-20

There is a slight (approximately 4 degrees) valgus angulation of the shaft of the ulna with respect to the greater sigmoid notch.

Medial Collateral Ligament Complex The medial collateral ligament consists of three parts: anterior, posterior, and transverse segments (Fig. 2-25). The anterior bundle is the most discrete component, the posterior portion being a thickening of the posterior capsule, and is well defined only in about 90 degrees of flexion. The transverse component (ligament of Cooper) appears to contribute little or nothing to elbow stability. The ligament originates from a broad anteroinferior surface of the epicondyle.65 The ulnar nerve rests on the posterior aspect of the medial epicondyle but is not intimately related to the fibers of the anterior bundle of the medial collateral ligament itself. This has obvious implications with regard to the treatment of ulnar nerve decompression by medial epicondylar ostectomy. A more obliquely oriented excision might be most appropriate to both decompress the ulnar nerve and preserve the collateral ligament origin. On the lateral projection, the origin of the anterior bundle of the medial collateral ligament is precisely at the axis of rotation at the anterior, inferior margins of the medial epicondyle62 (Fig. 2-26). The posterior bundle inserts along the midportion of the medial margin of the semilunar notch. The width of the anterior bundle is approximately 4 to 5 mm compared with 5 to 6 mm at the midportion of the fan-shaped posterior segment.56 Recently ultrasound assessment has proved helpful in further documenting the dimensions of these structures.61

20

Part I Fundamentals and General Considerations

FIGURE 2-21

21

16

10

5

0

Fibrous capsule

The carrying angle is formed by the variable relationship of the orientation of the humeral articulation referable to the long axis of the humerus and the valgus angular relationship of the greater sigmoid fossa referable to the long axis of the ulna. (Redrawn from Lanz, T., and Wachsmuth, W.: Praktische Anatomie. ARM, Berlin, Springer, 1959.)

Medial epicondyle

Lateral epicondyle Ant. part of ulnar collateral ligament

Radial collateral ligament Annular ligament Sacciform recess

Oblique cord

Tuberosity of radius Ulna

A

B

FIGURE 2-22

Distribution of the synovial membrane from the posterior aspect, demonstrating the presence of the synovial recess under the annular ligament and about the proximal ulna. (Redrawn from Beethman, W. P.: Physical Examination of the Joints. Philadelphia, W. B. Saunders Co., 1965.)

The function of the ligamentous structures is discussed in detail below. Clinically and experimentally, the anterior bundle is clearly the major portion of the medial ligament complex59 and has been divided into anterior, posterior and deep medial subcomponents.62

Lateral Ligament Complex Unlike the medial collateral ligament complex, with its rather consistent pattern, the lateral ligaments of the elbow joint are less discrete, and individual variation is

FIGURE 2-23

There is a cruciate orientation of the fibers of the anterior capsule that provides a good deal of its strength. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1978.)

common.30,31,40,75 Our investigation has suggested that several components make up the lateral ligament complex: (1) the radial collateral ligament, (2) the annular ligament, (3) a variably present accessory lateral collateral ligament, and (4) the lateral ulnar collateral ligament. These observations have now been confirmed by others. The current thinking is to consider the complex to be roughly in the shape “Y,” the arms of which attach to the anterior and posterior aspect of the semilunar notch13,72 (Fig. 2-27).

Chapter 2 Anatomy of the Elbow Joint

21

Musculocutaneous

Median Ulnar

Radial To anconeus

FIGURE 2-24

Left posterior

Left anterior

A typical distribution of the contributions of the musculocutaneous radial median and ulnar nerves to the joint capsule. (Redrawn from Gardner, E.: The innervation of the elbow joint. Anat. Rec. 102:161, 1948.)

Anterior bundle

Posterior bundle

Transverse ligament

FIGURE 2-25

The classic orientation of the medial collateral ligament, including the anterior and posterior bundles, and the transverse ligament. This last structure contributes relatively little to elbow stability.

Radial Collateral Ligament This structure originates from the lateral epicondyle and is actually a complex of several components (Fig. 2-28). Its superficial aspect provides a source of origin for a portion of the supinator muscle. The length averages approximately 20 mm with a width of approximately 8 mm. This portion of the ligament is almost uniformly taut throughout the normal range of flexion and extension, indicating that the origin of the ligament is very near the axis of flexion (Fig. 2-29).

FIGURE 2-26

The origin of the medial complex is at the axis of rotation, which is located at the anterior inferior aspect of the medial epicondyle. This is the projected center of the trochlea.

A strong band of tissue originating and inserting on the anterior and posterior margins of the lesser sigmoid notch forms the annular ligament and maintains the radial head in contact with the ulna. The ligament is tapered distally to give the shape of a funnel

Annular Ligament

22

Part I Fundamentals and General Considerations

FIGURE 2-27

Dissection demonstrating the “Y” orientation of the lateral collateral ligament complex.

FIGURE 2-29

The lateral collateral complex originates at the center of the lateral epicondyle.

Radial collateral ligament

Annular ligament Accessory collateral ligament

Lateral ulnar collateral ligament

FIGURE 2-28

Schematic representation of the radial collateral ligament complex showing several portions, one of which, termed the radial collateral ligament, extends from the humerus to the annular ligament. This is the portion that is implicated in clinical instability.

and contributes about four fifths of the fibro-osseous ring.52 The structure is not as simple as it appears because fibers arc medially and laterally to secure the annular ligament to the ulna.72 A synovial reflection extends distal to the lower margin of the annular ligament, forming the sacciform recess. The radial head is not a pure circular disc76; thus, it has been observed that the anterior insertion becomes taut during supination and the posterior aspect becomes taut during extremes of pronation.88 In 1985 Morrey and An first described the so-called lateral ulnar collateral ligament.56 Before this, however, Martin had

described a lateral ligament complex including “ . . . additional fibers inserting from the tubercle of the supinator crest to the humerus.” This structure subsequently has been demonstrated to be invariably present and critically important clinically. It originates from the lateral epicondyle and blends with the fibers of the annular ligament arching superficial and distal to it.66 The insertion is at the tubercle of the crest of the supinator on the ulna. Although the origin blends with the origin of the lateral collateral ligament complex occupying the posterior portion, the insertion is more discrete at the tubercle (Fig. 2-30). The function of this ligament is to provide stability to the ulnohumeral joint and was shown to be deficient in posterolateral rotatory instability of the joint.64,65 As confirmed by several subsequent assessments, the key factor is that this ligament represents the primary lateral stabilizer of the elbow and is taut in flexion and extension (Fig. 2-31). Accessory Lateral Collateral Ligament This definition has been applied by Martin to the ulnar insertion of discrete fibers on the tubercle of the supinator as described previously. Others have termed this the lateral arm of the “Y” ligament.72 Proximally, the fibers tend to blend with the inferior margin of the annular ligament (see Fig. 2-27). Its function is to further stabilize the annular ligament during varus stress.

Lateral Ulnar Collateral Ligament

A thin, fibrous layer covering the capsule between the inferior margin and the annular Quadrate Ligament

Chapter 2 Anatomy of the Elbow Joint

23

Radial collateral ligament Lateral ulnar collateral ligament

FIGURE 2-30

Artist’s rendition of lateral collateral complex noting the thickening of the lateral ulnar collateral ligament with a more discrete insertion at the tubercle of the supinator. In life, the supinator origin obscures the ligament, making it unnoticeable unless the supinator muscle has been removed. (From Pede.)

ligament and the ulna is referred to as the quadrate ligament20,60 or the ligament of Denucè.76 Spinner and Kaplan have demonstrated a functional role for the structure, describing the anterior part as a stabilizer of the proximal radial ulnar joint during full supination.76 The weaker posterior attachment stabilizes the joint in full pronation. Oblique Cord The oblique cord is a small and inconstant bundle of fibrous tissue formed by the fascia overlying the deep head of the supinator and extending from the lateral side of the tuberosity of the ulna to the radius just below the radial tuberosity (see Fig. 2-23). Although the morphologic significance is debatable53,76 and the structure is not considered to be of great functional consequence,31 it has been noted to become taut in full supination, and contracture of the oblique cord has been implicated in the etiology of idiopathic limitation of forearm supination.10 At this point, we consider this structure as a curiosity. Bursae The bursae were first detailed by Monro in 1788, and several bursae have been described at the elbow joint.55 Lanz recognized seven bursae, including three associated with the triceps.52 On the posterior aspect of the elbow, the superficial olecranon bursa, which develops around age 7 years,18 between the olecranon process and the subcutaneous tissue is well

FIGURE 2-31

The lateral ulnar collateral ligament complex has an origin at the axis of rotation and thus is isometric, being taut both in extension (A) and in flexion (B). Note presence of the accessory ligament.

known33 (Fig. 2-32). A deep subtendinous bursa is present as the triceps inserts on the tip of the olecranon. An occasional deep subtendinous bursa is likewise present between the tendon and the tip of the olecranon. A bursa has also even been described deep to the anconeus muscle in about 12% of subjects by Henle,36 but we have not appreciated such a structure during more than 500 exposures of this region. On the medial and lateral aspects of the joint, the subcutaneous medial epicondylar bursa is frequently present, and the lateral subcutaneous epicondylar bursa occasionally has been observed. The radiohumeral bursa lies deep to the common extensor tendon, below the extensor carpi radialis brevis and superficial to the radiohumeral joint capsule. This entity has been implicated by several authors17,67 in the etiology of lateral epicondylitis but is probably not a major factor. The constant bicipitoradial bursa separates the biceps tendon from the tuberosity

24

Part I Fundamentals and General Considerations

Medial epicondylar B.

Lat. epicondylar B.

Ulnar n. B. Subanconeus B. Subtendinous B. Intratendinous B. Olecranon B.

Sub ext. carpi radialis brevis B. (Radiohumeral B.)

FIGURE 2-32

Posterior view of the elbow demonstrating the superficial and deep bursae that are present about this joint.

of the radius (see Fig. 2-9). Less commonly appreciated is the deep cubital interosseous bursa lying between the lateral aspect of the biceps tendon and the ulna, brachialis, and supinator fascia. This bursa is said to be present in about 20% of individuals.75 The clinical significance of the relevant bursae about the elbow is detailed in Chapter 85.

VESSELS BRACHIAL ARTERY AND ITS BRANCHES The cross-sectional relationship of the vessels, nerves, muscles, and bones is shown in Figure 2-33. The brachial artery descends in the arm, crossing in front of the intramuscular septum to lie anterior to the medial aspect of the brachialis muscle. The median nerve crosses in front of and medial to the artery at this point, near the middle of the arm (Fig. 2-34). The artery continues distally at the medial margin of the biceps muscle and enters the antecubital space medial to the biceps tendon and lateral to the nerve (Fig. 2-35). At the level of the radial head, it gives off its terminal branches, the ulnar and radial arteries, which continue into the forearm. The brachial artery usually is accompanied by medial and lateral brachial veins. Proximally, in addition to its numerous muscular and cutaneous branches, the large,

deep brachial artery courses posteriorly and laterally to bifurcate into the medial and radial collateral arteries. The medial collateral artery continues posteriorly, supplying the medial head of the triceps and ultimately anastomosing with the interosseous recurrent artery at the posterior aspect of the elbow. The radial collateral artery penetrates the lateral intermuscular septum and accompanies the radial nerve into the antecubital space, where it anastomoses with the radial recurrent artery at the level of the lateral epicondyle. The detailed vascular anatomy of the elbow region has been nicely described recently in great detail by Yamaguchi et al.89 The major branches of the brachial artery are the superior and inferior ulnar collateral arteries, which originate medial and distal to the profunda brachial artery. The superior ulnar collateral artery is given off just distal to the midportion of the brachium, penetrates the medial intermuscular septum, and accompanies the ulnar nerve to the medial epicondyle, where it terminates by anastomosing with the posterior ulnar recurrent artery and variably with the inferior ulnar collateral artery (Fig. 2-36). The inferior ulnar collateral artery arises from the medial aspect of the brachial artery about 4 cm proximal to the medial epicondyle. It continues distally for a short course, dividing into and anastomosing with branches of the anterior ulnar recurrent artery, and it supplies a portion of the pronator teres muscle.

Chapter 2 Anatomy of the Elbow Joint

25

57

57

58 59

59 60

61

61

A

B Biceps brachii m. Brachialis m. Radial n. Brachioradialis m. Ext. carpi radialis longus m.

C

D

E

(57)

Lat. intermuscular septum Humerus

Brachial a. and vv. Median n. Basilic v. Ulnar n. Medial intermuscular septum Triceps brachii m.

Medial antebrachial cutan. n. Pronator teres m. Flexor carpi radialis m. Basilic v. Ext. carpi radialis Flexor digitorum superficialis m. longus and brevis mm. Ulnar collateral lig. Dorsal antebrachial Ulnar n. cutan. n. (59) Flexor carpi ulnaris m. Tendon of common ext. digitorum, Flexor digitorum profundus m. carpi ulnaris, and digiti minimi mm. Anconeus m. Pronator teres m. Radial a. and v. Tendon of biceps brachii m. Lat. antebrachial cutan. n. Medial antebrachial cutan. n. Superficial radial n. Flexor carpi radialis m. Brachioradialis m. Palmaris longus m. Ext. carpi radialis Common interosseous a. and median n. longus and brevis mm. Flexor digitorum superficialis m. Antebrachii fascia Ulnar n. Radius Flexor carpi ulnaris m. Deep radial n. Ulnar a. and v. Common ext. digitorum m. Flexor digitorum profundus m. Ext. digiti minimi m. (61) Ulna Ext. carpi ulnaris m. Interosseous membrane Supinator m. Anconeus m.

FIGURE 2-33

Cross-sectional relationships of the muscles (A) and the neurovascular bundles (B). C, The region above the elbow joint. D, View taken across the elbow joint. E, View just distal to the articulation. (Redrawn from Eycleshymer, A. C., and Schoemaker, D. M.: A Cross-Section Anatomy. New York, D. Appleton and Co., 1930.)

26

Part I Fundamentals and General Considerations

Brachialis Radial n. Brachioradialis Radial recurrent a. Deep and superficial branches of radial n. Supinator Extensor carpi radialis longus Flexor digitorum sublimis Pronator teres Radial a.

Biceps and lacertus fibrosus Median n. Brachial a. Pronator teres, humeral head Flexor carpi radialis and palmaris longus Pronator teres, ulnar head Ulnar n. Ant. and post. ulnar recurrent aa. Ulnar a. Common interosseous a. Posterior and anterior interosseous aa. Anterior interosseous n. Flexor carpi ulnaris

Flexor pollicis longus

Flexor digitorum profundus Dorsal branch of ulnar n.

FIGURE 2-34 Ulnar a. and n. Volar interosseous a. and n. Pronator quadratus

Median n.

Abductor pollicis longus

RADIAL ARTERY The radial artery typically originates at the level of the radial head, emerges from the antecubital space between the brachioradialis and the pronator teres muscle, and continues down the forearm under the brachioradialis muscle. A more proximal origin occurs in up to 15% of individuals.54 The radial recurrent artery originates laterally from the radial artery just distal to its origin. It ascends laterally on the supinator muscle to anastomose with the radial collateral artery at the level of the lateral epicondyle, to which it provides circulation. For better visualization, the radial recurrent artery sometimes is sacrificed with the anterior elbow exposure.

ULNAR ARTERY The larger of the two terminal branches of the brachial artery is the ulnar artery. There is relatively little variation in its origin, which is usually at the level of the radial head. The artery traverses the pronator teres between its two heads and continues distally and medially behind the flexor digitorum superficialis muscle. It emerges medially to continue down the medial aspect of the forearm under the cover of the flexor carpi ulnaris. Two

Anterior aspect of the elbow region demonstrating the intricate relationships between the muscles, nerves, and vessels. (Redrawn from Hollinshead, W. H.: The back and limbs. In Anatomy for Surgeons, Vol. 3. New York, Harper & Row, 1969, p. 379.)

recurrent branches originate just distal to the origin of the ulnar artery. The anterior ulnar recurrent artery ascends deep to the humeral head of the pronator teres and deep to the medial aspect of the brachialis muscle to anastomose with the descending superior and inferior ulnar collateral arteries. The posterior ulnar recurrent artery originates with or just distal to the smaller anterior ulnar recurrent artery and passes proximal and posterior between the superficial and deep flexors posterior to the medial epicondyle. This artery continues proximally with the ulnar nerve under the flexor carpi ulnaris to anastomose with the superior ulnar collateral artery. Additional extensive communication with the inferior ulnar and middle collateral branches constitutes the rete articulare cubiti (see Fig. 2-35). The common interosseous artery is a large vessel originating 2.5 cm distal to the origin of the ulnar artery. It passes posteriorly and distally between the flexor pollicis longus and the flexor digitorum profundus just distal to the oblique cord, dividing into anterior and posterior interosseous branches. The interosseous recurrent artery originates from the posterior interosseous branch. This artery runs proximally through the supinator muscle to anastomose with the vascular network of the olecranon (see Fig. 2-36).

Chapter 2 Anatomy of the Elbow Joint

27

RC

MC SUC SUC

IU

C

B

IUC

RR RR

PUR PUR IR

R

FIGURE 2-36

FIGURE 2-35

Illustration of the anterior extraosseous vascular anatomy demonstrating the medial arcade and the relationship of the radial recurrent artery (RR) to the proximal aspect of the radius. The inferior ulnar collateral artery (IUC) provides perforators to the supracondylar region, medial aspect of the trochlea, and medial epicondyle before it courses posteriorly to anastomose with the superior ulnar collateral (SUC) and posterior ulnar recurrent (PUR) arteries. The radial recurrent artery provides an osseous perforator to the radius as it travels proximally and posterior. B, brachial artery; R, radial artery. (Redrawn from Yamaguchi, K., Sweet, F. A., Bindra, R., Morrey, B. F., and Gelberman, R. H.: The extraosseous and intraosseous arterial anatomy of the adult elbow. J. Bone Joint Surg. 79A:1654, 1997.)

NERVES Specific clinical and pertinent anatomic aspects of the nerves in the region of the elbow are discussed in subsequent chapters as appropriate. A general survey of the common anatomic patterns is given here (see Fig. 2-33).

MUSCULOCUTANEOUS NERVE The musculocutaneous nerve originates from C5-8 nerve roots and is a continuation of the lateral cord. It innervates the major elbow flexors, the biceps and brachialis,

Illustration of the posterior collateral circulation of the elbow. There are perforating vessels on the posterior aspect of the lateral epicondyle, in the olecranon fossa, and on the medial aspect of the trochlea. The tip of the olecranon is supplied by perforators from the posterior arcade in the olecranon fossa. The superior ulnar collateral artery (SUC) is seen terminating in the posterior arcade. IUC, inferior ulnar collateral artery; PUR, posterior ulnar recurrent artery; IR, interosseous recurrent artery, RR, radial recurrent artery; RC, radial collateral artery; MC, middle collateral artery. (Redrawn from Yamaguchi, K., Sweet, F. A., Bindra, R., Morrey, B. F., and Gelberman, R. H.: The extraosseous and intraosseous arterial anatomy of the adult elbow. J. Bone Joint Surg. 79A:1655, 1997.)

and continues through the brachial fascia lateral to the biceps tendon, terminating as the lateral antebrachial cutaneous nerve (Fig. 2-37). The motor branch enters the biceps and the brachialis approximately 15 and 20 cm below the tip of the acromion, respectively.48

MEDIAN NERVE Arising from the C5-8 and T1 nerve roots, the median nerve enters the anterior aspect of the brachium, crossing in front of the brachial artery as it passes across the intermuscular septum. It follows a straight course into the medial aspect of the antecubital fossa, medial to the biceps tendon and the brachial artery. It then passes under the bicipital aponeurosis. The first motor branch is provided to the pronator teres, through which it

28

Part I Fundamentals and General Considerations

Musculocutaneous nerve

Coracobrachialis

Median nerve

Long head of biceps

Lat. cutaneous nerve of forearm

Short head of biceps Brachialis

Pronator teres (C6, C7) Flexor carpi radialis (C6-C8) Flexor digitorum superficialis (C6-T1)

Palmaris longus (C7-T1) communicating branch with ulnar nerve

Flexor pollicis longus (C6-C8) Pronator quadratus (C6-T1)

Flexor digitorum profundus (C8, T1)

Opponens pollicis (C7, C8?, T1) Abductor pollicis brevis (C6, C7, C8?)

FIGURE 2-37 The musculocutaneous nerve innervates the flexors of the elbow and continues distal to the joint as the lateral cutaneous nerve of the forearm. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

passes.2,39 It enters the forearm and continues distally under the flexor digitorum superficialis within the fascial sheath of this muscle. There are no branches of the median nerve in the arm (Fig. 2-38). In the cubital fossa, a few small articular branches are given off before the motor branches to the pronator teres, the flexor carpi radialis, the palmaris longus, and the flexor digitorum superficialis. Because all branches arise medially, medial retraction of the nerve during exposure of the anterior aspect of the elbow is a safe technique. The anterior interosseous nerve innervates the flexor pollicis longus and the lateral portion of the flexor digitorum profundus. It arises from the median nerve near the inferior border of the pronator teres and travels along the anterior aspect of the interosseous membrane in the company of the anterior interosseous artery.

RADIAL NERVE The radial nerve is a continuation of the posterior cord and originates from the C6, C7, and C8 nerve roots with

Flexor pollicis brevis (C6-C8) Lumbricals 1 and 2 (C7-T1)

FIGURE 2-38 The median nerve innervates the flexor pronator group of muscles about the elbow, but there are no branches above the joint. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

variable contributions of the C5 and T1 roots. In the midportion of the arm, the nerve courses laterally just distal to the deltoid insertion to occupy the spiral groove in the humerus that bears its name. Before entering the anterior aspect of the arm, it gives off motor branches to the medial and lateral head of the triceps, accompanied by the deep branch of the brachial artery. It then emerges inferiorly and laterally to penetrate the lateral intermuscular septum. The nerve is at risk for injury from surgery or fracture at this site. Two recent studies have placed the position of the radial nerve as 54% of the acromion/ulnar distance22 or 1.7% of the transcondylar distance.41 After penetrating the lateral intermuscular septum in the distal third of the arm, it descends anterior to the lateral epicondyle behind the brachioradialis. It innervates the brachioradialis with a single branch to this muscle. In the antecubital space, the nerve divides into the superficial and deep branches. The superficial branch is a continuation of the radial nerve

Chapter 2 Anatomy of the Elbow Joint

29

Radial nerve

Triceps (C6-C8, T1) Post. cutaneous nerve of arm Post. cutaneous nerve of forearm Anconeus Deep branch of radial nerve

Brachioradialis (C5, C6) Extensor carpi radialis longus and brevis (C6-C8) Superficial branch of radial nerve

Extensor carpi ulnaris (C6?, C7, C8) Extensor digitorum (C6, C7, C8)

Extensor pollicis longus (C6?, C7, C8) Abductor pollicis longus (C6?, C7, C8) Extensor pollicis brevis

FIGURE 2-39

The muscles innervated by the right radial nerve. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

and extends into the forearm to innervate the middorsal cutaneous aspect of the forearm (Fig. 2-39). The motor branches of the radial nerve are given off to the triceps above the spiral groove except for the branch to the medial head of the triceps, which originates at the entry to the spiral groove. This branch continues distally through the medial head to terminate as a muscular branch to the anconeus. This accounts for the variability of the anconeus when rotated or reflected from its origin.11,44,68 In the antecubital space, the recurrent radial nerve curves around the posterolateral aspect of the radius, passing deep to the supinator muscle, which it innervates. During its course through the supinator muscle, the nerve lies over a bare area, which is distal to and opposite to the radial tuberosity.23 The nerve is believed to be at risk at this site with fractures of the proximal radius.79 It emerges from the muscle as the posterior interosseous nerve, and the recurrent branch innervates the extensor digitorum minimi, the extensor carpi ulnaris, and occasionally, the anconeus. The posterior interosseous nerve is accompanied by the posterior interosseous artery and sends further muscle branches distally to supply the abductor pollicis longus, the extensor pollicis longus, the extensor pollicis brevis, and the extensor indicis on the dorsum of the forearm. The nerve is subject to compression as it passes through the supinator muscle15 or from

synovial proliferation.25,28 Compression and entrapment problems are described in detail in Chapter 81.

ULNAR NERVE The ulnar nerve is derived from the medial cord of the brachial plexus from roots C8 and T1. In the midarm, it passes posteriorly through the medial intermuscular septum and continues distally anterior to the septum and under the medial margin of the triceps. It is accompanied by the superior ulnar collateral branch of the brachial artery and the ulnar collateral branch of the radial artery. Although supposedly there are no branches of this nerve in the brachium, an occasional motor branch to the triceps is encountered (Fig. 2-40). The ulnar nerve passes into the cubital tunnel under the medial epicondyle and rests against the posterior portion of the medial collateral ligament, where a groove in the ligament accommodates this structure. The roof of the cubital tunnel recently has been defined and termed the cubital tunnel retinaculum.64 Retinacular absence accounts for congenital subluxation of the ulnar nerve. Furthermore, the structure flattens with elbow flexion, thus decreasing the capacity of the cubital tunnel (Fig. 2-41).64 This accounts for the clinical observation of ulnar nerve paresthesia with elbow flexion. Similarly, elbow instability can cause traction injury to the nerve.51

30

Part I Fundamentals and General Considerations

Ulnar nerve

Flexor digitorum profundus (C8, T1)

Median nerve

Communicating branch Flexor carpi ulnaris (C8, T1)

Deep head of flexor pollicis (C6-C8) Adductor pollicis (C7, C8, T1)

Digiti Minimi

Triceps m.

Abductor flexor opponens (C7, C8?, T1)

Flexion

Lumbricals (C7-C8, T1) Palmar and dorsal interossei (C7?, C8, T1)

FIGURE 2-40

Muscles innervated by the right ulnar nerve. There are no muscular branches of this nerve above the elbow joint. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

A few small capsular twigs are given to the elbow joint in this region.8 As the nerve enters the forearm between the two heads of the flexor carpi ulnaris, it gives off a single nerve to the ulnar origin of the pronator and one to the epicondylar head of the flexor carpi ulnaris. Distally, the nerve sends a motor branch to the ulnar half of the flexor digitorum profundus. Two cutaneous nerves arise from the ulnar nerve in the distal half of the forearm and innervate the skin of the wrist and the ulnar two digits of the hand.

MUSCLES Relevant features of the origin, insertion, and function of the muscles of the elbow region are covered in other chapters dealing with surgical exposure, functional examination, and biomechanics. This information also is discussed in various chapters when dealing with specific pathology. The following description will serve as a basic overview.

Ulnar n. OI ME

B

CTR

FIGURE 2-41 With flexion the cubital tunnel flattens, compressing the ulnar nerve (A and B). (Redrawn from O’Driscoll, S. W., Horii, E., Carmichael, S. W., and Morrey, B. F.: The cubital tunnel and ulnar neuropathy. J. Bone Joint Surg. 73B:613, 1991.)

ELBOW FLEXORS Biceps The biceps covers the brachialis muscle in the distal arm and passes into the cubital fossa as the biceps tendon, which attaches to the posterior aspect of the radial tuberosity (Fig. 2-42). The constant bicipitoradial bursa separates the tendon from the anterior aspect of the tuberosity, and the cubital bursa has been described as separating the tendon from the ulna and the muscles covering the radius (see Fig. 2-9). The bicipital aponeurosis, or lacertus fibrosus, is a broad, thin band of tissue that is a continuation of the anterior medial and distal muscle fasciae. It runs obliquely to cover the median nerve and brachial artery and inserts into the deep fasciae of the forearm and possibly into the ulna as well.19 The biceps is a major flexor of the elbow that has a large cross-sectional area but an intermediate mechanical advantage because it passes relatively close to the

Chapter 2 Anatomy of the Elbow Joint

Acromion

Trapezius

31

Clavicular portion of pectoralis major

Groove for cephalic vein Deltoid Sternocostal portion of pectoralis major Subscapularis Coracobrachialis Deltoid tuberosity

Serratus anterior Teres major and latissimus dorsi

Brachialis Lat. head of triceps

Short head of biceps brachii Long head of biceps brachii

Lat. intermuscular septum Brachioradialis Extensor carpi radialis longus

Tendon of biceps brachii Bicipital aponeurosis Pronator teres

axis of rotation. In the pronated position, the biceps is a strong supinator.6 The distal insertion may undergo spontaneous rupture,57,78 and this condition is discussed in detail later (Chapter 34).

Brachialis This muscle has the largest cross-sectional area of any of the elbow flexors but suffers from a poor mechanical advantage because it crosses so close to the axis of rotation. The origin consists of the entire anterior distal half of the humerus, and it extends medially and laterally to the respective intermuscular septa (Fig. 2-43). The muscle crosses the anterior capsule, with some fibers inserting into the capsule that are said to help retract the capsule during elbow flexion. The major attachment is to the coronoid process about 2 mm distal from its articular margin. More than 95% of the cross-sectional area is muscle tissue at the elbow joint,50 a relationship that may account for the high incidence of trauma to this muscle and the development of myositis ossificans with elbow dislocation.84 The muscle is innervated by the musculocutaneous nerve. The lateral portion of the muscle covers the radial nerve as it spirals around the distal humerus. The median nerve and brachial artery are superficial to the brachialis and lie behind the biceps in the distal humerus.

FIGURE 2-42

Anterior aspect of the arm and elbow region demonstrating the major flexors of the joint, the brachialis, and the biceps muscles. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

Brachioradialis The brachioradialis has a lengthy origin along the lateral supracondylar bony column that extends proximally to the level of the junction of the mid and distal humerus (see Fig. 2-43). The origin separates the lateral head of the triceps and the brachialis muscle. The lateral border of the cubital fossa is formed by this muscle, which crosses the elbow joint with the greatest mechanical advantage of any elbow flexor. It progresses distally to insert into the base of the radial styloid (Figs. 2-44 and 2-45). The muscle protects and is innervated by the radial nerve (C5, C6) as it emerges from the spiral groove. Its major function is elbow flexion. Rarely, the muscle may be ruptured.35

Extensor Carpi Radialis Longus The extensor carpi radialis longus originates from the supracondylar bony column joint just below the origin of the brachioradialis (see Fig. 2-44). The origin of this muscle is identified as the first fleshy fibers observed proximal to the common extensor tendon. As it continues into the midportion of the dorsum of the forearm, it becomes largely tendinous and inserts into the dorsal base of the second metacarpal. Innervated by the radial nerve (C6, C7), the motor branches arise just distal to those of the brachioradialis muscle.

32

Part I Fundamentals and General Considerations

Supraspinatus

Subscapularis

Pectoralis major

Latissimus dorsi Teres major

Deltoid

Coracobrachialis

Brachialis Brachioradialis Origins Insertions

Extensor carpi radialis longus

Common extensor tendon

Pronator teres Common flexor tendon

FIGURE 2-43

Anterior humeral origin and insertion of muscles that control flexion of the elbow joint.

In addition to wrist extension, its orientation suggests that this muscle might function as an elbow flexor. Clinically, the origin of this muscle and its relationship with that of the extensor carpi radialis brevis have been implicated in the pathologic anatomy of tennis elbow by Nirschl (Chapter 44).

Extensor Carpi Radialis Brevis The extensor carpi radialis brevis originates from the lateral superior aspect of the lateral epicondyle (see Fig. 2-43). Its origin is the most lateral of the extensor group and is covered by the extensor carpi radialis longus. This relationship is important as the most commonly implicated site of lateral epicondylitis. The extensor digitorum communis originates from the common extensor tendon and is just medial or ulnar to the extensor carpi radialis brevis. At its humeral origin, the fibers of the extensor digitorum communis and brevis are grossly and histologically indistinguishable from one another32 (see Fig. 2-44). The longus and brevis shares the same extensor compartment as they cross the wrist under the extensor retinaculum. The brevis inserts into the dorsal base of the third metacarpal. The function of the extensor carpi radialis brevis is pure wrist extension, with little or no radial or ulnar deviation.1 The extensor carpi radialis

brevis is innervated by fibers of the sixth and seventh cervical nerves. The motor branch arises from the radial nerve in the region of its division into deep and superficial branches.

Extensor Digitorum Communis Originating from the anterior distal aspect of the lateral epicondyle, the extensor digitorum communis accounts for most of the contour of the extensor surface of the forearm (see Fig. 2-44). The muscle extends and abducts the fingers. According to Wright, the muscle can assist in elbow flexion when the forearm is pronated. This observation is not, however, supported by our crosssectional studies.1 Innervation is from the deep branch of the radial nerve, with contributions from the sixth through eighth cervical nerves.

Extensor Carpi Ulnaris The extensor carpi ulnaris originates from two heads, one above and the other below the elbow joint. The humeral origin is the most medial of the common extensor group (Fig. 2-46) (see also Fig. 2-43). The ulnar attachment is along the aponeurosis of the anconeus and at the superior border of this muscle. It is a valuable landmark for exposures of the lateral elbow joint. The insertion is on the dorsal base of the fifth metacarpal after crossing the wrist in its own compartment under the extensor retinaculum. The extensor carpi ulnaris is a wrist extensor and ulnar deviator. Fibers of the sixth through eighth cervical nerve routes innervate the muscle from branches of the deep radial nerve.

Supinator This flat muscle is characterized by the virtual absence of tendinous tissue and a complex origin and insertion. It originates from three sites above and below the elbow joint: (1) the lateral anterior aspect of the lateral epicondyle; (2) the lateral collateral ligament; and (3) the proximal anterior crest of the ulna along the crista supinatoris. The form of the muscle is approximately that of a rhomboid, because it runs obliquely, distally, and radially to wrap around and insert diffusely on the proximal radius, beginning lateral and proximal to the radial tuberosity and continuing distal to the insertion of the pronator teres at the junction of the proximal and middle third of the radius (see Fig. 2-46). It is important to note that the radial nerve passes through the supinator to gain access to the extensor surface of the forearm. This anatomic feature is clinically significant with regard to exposure of the lateral aspect of the elbow joint and the proximal radius and in certain entrapment syndromes.76 The muscle obviously supinates the forearm but is a weaker supinator than the biceps.38 Unlike the biceps,

Chapter 2 Anatomy of the Elbow Joint

33

Biceps brachii Triceps brachii Olecranon Lateral epicondyle of humerus

Brachialis Brachioradialis Extensor carpi radialis brevis

Extensor digitorum Extensor digiti minimi Abductor pollicis longus Extensor carpi ulnaris

Head of ulna

Extensor pollicis brevis Tendons of extensor carpi radialis longus and brevis Styloid process of radius

FIGURE 2-44

The musculature of the posterolateral aspect of the right forearm. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

ELBOW EXTENSORS Triceps Brachii

FIGURE 2-45

Posterior view of the radius and ulna demonstrating the insertion of the extensors of the elbow as well as the origin of the forearm musculature.

however, the effectiveness of the supinator is not altered by the position of elbow flexion. The innervation is derived from the muscular branch given off by the radial nerve just before and during its course through the muscle with nerve fibers derived primarily from the sixth cervical root.

The entire posterior musculature of the arm is composed of the triceps brachii (see Fig. 2-39). The long head has a discrete origin from the infraglenoid tuberosity of the scapula. The lateral head originates in a linear fashion from the proximal lateral intramuscular septum on the posterior surface of the humerus. The medial head originates from the entire distal half of the posteromedial surface of the humerus bounded laterally by the radial groove and medially by the intramuscular septum. Thus, each head originates distal to the other, with progressively larger areas of origin. The long and lateral heads are superficial to the deep medial head, blending in the midline of the humerus to form a common muscle that then tapers into the triceps tendon and attaches to the tip of the olecranon with Sharpey’s fibers.14 The tendon usually is separated from the olecranon by the subtendinous olecranon bursa. The distal 40% of the triceps mechanism consists of a layer of fascia that blends with the triceps distally. Innervated by the radial nerve, the long and lateral heads are supplied by branches that arise proximal to

34

Part I Fundamentals and General Considerations

Triceps brachii Olecranon

Brachioradialis Lateral epicondyle

Anconeus

Posterior border of ulna

Extensor carpi radialis longus Supinator Extensor carpi radialis brevis

Extensor carpi ulnaris Flexor carpi ulnaris Extensor pollicis longus Extensor indicis Styloid process of ulna

Radius Abductor pollicis longus Extensor pollicis brevis Tendons of extensor radialis longus and brevis

Dorsal interossei Extensor indicis Tendon of extensor digitorum

the entrance of the radial nerve into the groove. The medial head is innervated distal to the groove with a branch that enters proximally and passes through the entire medial head to terminate by innervating the anconeus, an anatomic feature of considerable importance when considering some approaches (e.g., Kocher, BryanMorrey, Boyd, and Pankovitch) to the joint. The function of the triceps is to extend the elbow. Lesions of the nerve in the midportion of the humerus usually do not prevent triceps function that is provided by the more proximally innervated lateral and long heads.

Subanconeus Muscle The attachment of some muscle fibers of the medial head of the triceps to the posteromedial capsule has been termed the subanconeus muscle. This may have some functional relevance of stabilizing the fat pad to help cushion the elbow as it comes into full extension.87

Anconeus This muscle has little tendinous tissue because it originates from a rather broad site on the posterior aspect of the lateral epicondyle and from the lateral triceps

FIGURE 2-46

The extensor aspect of the forearm demonstrating the deep muscle layer after the extensor digitorum and extensor digiti minimi have been removed. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

fascia and inserts into the lateral dorsal surface of the proximal ulna (see Fig. 2-46). It is innervated by the terminal branch of the nerve to the medial head of the triceps. Curiously, the function of this muscle has been the subject of considerable speculation. Possibly the most accurate description of function is that proposed by Basmajian and Griffin and by DaHora, who suggest that its primary role is that of a joint stabilizer.5,21 The muscle covers the lateral portion of the annular ligament and the radial head. For the surgeon, the major significance of this muscle is its position as a key landmark in various lateral and posterolateral exposures and is emerging for usefulness reconstruction of the lateral elbow.

FLEXOR PRONATOR MUSCLE GROUP Pronator Teres This is the most proximal of the flexor pronator group. There are two heads of origin: The largest arises from the anterosuperior aspect of the medial epicondyle and the second from the coronoid process of the ulna, an attachment absent in about 10% of individuals39 (see Fig. 2-37). The two origins of the pronator muscle provide an arch through which the median nerve passes to gain

Chapter 2 Anatomy of the Elbow Joint

access to the forearm. This anatomic characteristic is a significant feature in the etiology of the median nerve entrapment syndrome and is discussed in detail in Chapter 80. The common muscle belly proceeds radially and distally under the brachioradialis, inserting at the junction of the proximal and middle portions of the radius by a discrete broad tendinous insertion into a tuberosity on the lateral aspect of the bone. Obviously, a strong pronator of the forearm, it also is considered a weak flexor of the elbow joint.1,7,82 The muscle usually is innervated by two motor branches from the median nerve before the nerve leaves the cubital fossa.

35

wrist flexor. At the elbow no significant flexion moment is present.1,24

Palmaris Longus This muscle, when present, arises from the medial epicondyle, and from the septa it shares with the flexor carpi radialis and flexor carpi ulnaris (see Fig. 2-43). It becomes tendinous in the proximal portion of the forearm and inserts into and becomes continuous with the palmar aponeurosis. It is absent approximately in 10% of extremities.71 Its major function is as a donor tendon for reconstructive surgery, and it is innervated by a branch of the median nerve.

Flexor Carpi Radialis The flexor carpi radialis originates just inferior to the origin of the pronator teres and the common flexor tendon at the anteroinferior aspect of the medial epicondyle (see Fig. 2-43). It continues distally and radially to the wrist, where it can be easily palpated before it inserts into the base of the second and sometimes the third metacarpal. Proximally, the muscle belly partially covers the pronator teres and palmaris longus muscles and shares a common origin from the intermuscular septum, which it shares with these muscles. The innervation is from one or two twigs of the median nerve (C6, C7), and its chief function is as a

Flexor Carpi Ulnaris The flexor carpi ulnaris is the most posterior of the common flexor tendons originating from the medial epicondyle (see Figs. 2-38 and 2-43). A second and larger source of origin is from the medial border of the coronoid and the proximal medial aspect of the ulna. The ulnar nerve enters and innervates (T7-8 and T1) the muscle between these two sites of origin with two or three motor branches given off just after the nerve has entered the muscle. These are the first motor branches of the ulnar nerve, and therefore, they are useful in localizing the level of an ulnar nerve lesion. The muscle

Brachial artery Median nerve Triceps brachii Aponeurosis of biceps brachii

Brachioradialis Radial artery Pronator teres (cut)

Pronator teres (cut) Brachialis Ulnar artery Humeral head Radial head

flexor digitorum superficialis

Superficial branch of radial nerve Extensor carpi radialis longus

Flexor pollicis longus Flexor carpi ulnaris

Abductor pollicis longus Extensor pollicis brevis Flexor carpi radialis (cut) Flexor retinaculum

Ulnar artery and nerve Flexor digitorum profundus Median nerve Deep layer of flexor retinaculum

Tendon of flexor digitorum profundus

FIGURE 2-47 The flexor digitorum superficialis is demonstrated after the palmaris longus and flexor carpi radialis has been removed. The pronator teres has been transected and reflected. The important relationships of the nerves and arteries should be noted. (Redrawn from Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976.)

36

Part I Fundamentals and General Considerations

continues distally to insert into the pisiform, where the tendon is easily palpable, because it serves as a wrist flexor and ulnar deviator. With an origin posterior to the axis of rotation, weak elbow extension also may be provided by the flexor carpi ulnaris.1

Flexor Digitorum Superficialis This muscle is deep to those originating from the common flexor tendon but superficial to the flexor digitorum profundus; thus, it is considered the intermediate muscle layer. This broad muscle has a complex origin (Fig. 2-47). Medially, it arises from the medial epicondyle by way of the common flexor tendon and possibly from the ulnar collateral ligament and the medial aspect of the coronoid.38 The lateral head is smaller and thinner and arises from the proximal two thirds of the radius. The unique origin of the muscle forms a fibrous margin under which the median nerve and the ulnar artery emerge as they exit from the cubital fossa. The muscle is innervated by the median nerve (C7, C8, T1) with branches that originate before the median nerve enters the pronator teres. The action of the flexor digitorum superficialis is flexion of the proximal interphalangeal joints.

References 1. An, K. N., Hui, F. C., Morrey, B. F., Linscheid, R. L., and Chao, E. Y.: Muscles across the elbow joint: a biomechanical analysis. J. Biomechan. 14:659, 1981. 2. Anson, B. J., and McVay, C. B.: Surgical Anatomy, 5th ed., Vol. 2. Philadelphia, W. B. Saunders Co., 1971. 3. Atkinson, W. B., and Elftman, H.: The carrying angle of the human arm as a secondary sex character. Anat. Rec. 91:49, 1945. 4. Barnard, L. B., and McCoy, S. M.: The supracondyloid process of the humerus. J. Bone Joint Surg. 28:845, 1946. 5. Basmajian, J. V., and Griffin, W. R.: Function of anconeus muscle. J. Bone Joint Surg. 54A:1712, 1972. 6. Basmajian, J. V., and Latif, A.: Integrated actions and functions of the two flexors of the elbow: a detailed myographic analysis. J. Bone Joint Surg. 39A:1106, 1957. 7. Basmajian, J. V., and Travell, A.: Electromyography of the pronator muscles in the forearm. Anat. Rec. 139:45, 1961. 8. Bateman, J. E.: Denervation of the elbow joint for the relief of pain: a preliminary report. J. Bone Joint Surg. 30B:635, 1948. 9. Beetham, W. P.: Physical Examination of the Joints. Philadelphia, W. B. Saunders Co., 1965. 10. Bert, J. M., Linscheid, R. L., and McElfresh, E. C.: Rotatory contracture of the forearm. J. Bone Joint Surg. 62A:1163, 1980. 11. Boyd, H. B.: Surgical exposure of the ulna and proximal third of the radius through one incision. Surg. Gynec. Obstet. 71:86, 1940.

12. Boyd, H. D., and Anderson, L. D.: A method for reinsertion of the biceps tendon brachii tendon. J. Bone Joint Surg. 43A:1141, 1961. 13. Bozkurt, M., Acar, H. I., Apaydin, N., Leblebicioglu, G., Elhan, A., Tekdemir, I., and Tonuk, E.: The annular ligament: an anatomical study. Am. J. Sports Med. 33:114, 2005. 14. Bryan, R. S., and Morrey, B. F.: Extensive posterior exposure of the elbow: a triceps-sparing approach. Clin. Orthop. 166:188, 1982. 15. Capener, N.: The vulnerability of the posterior interosseous nerve of the forearm: a case report and anatomic study. J. Bone Joint Surg. 48B:770, 1966. 16. Caputo, A. E., Mazzocca, A. D., and Santoro, V. M.: The nonarticulating portion of the radial head: anatomic and clinical correlations for internal fixation. J. Hand Surg. 23A(6):1082, 1998. 17. Carp, L.: Tennis elbow (epicondylitis) caused by radiohumeral bursitis. Arch. Surg. 24:905, 1932. 18. Chen, J., Alk, D., Eventov, I., and Weintroub, S.: Development of the olecranon bursa: an anatomic cadaver study. Acta Orthop. Scand. 58:408, 1987. 19. Congdon, E. D., and Fish, H. S.: The chief insertion of the biceps after neurosis in the ulna: a study of collagenous bundle patterns of antebrachial fascia and bicepital aponeurosis. Anat. Rec. 116:395, 1953. 20. Cunningham, D. J.: In Romanes, G. J. (ed.): Textbook of Anatomy, 12th ed. New York, Oxford University Press, 1981. 21. DaHora, B.: Musculus Anconeus. Thesis, University of Recife, Recife, Brazil, 1959. Cited by Basmajian, J. V., and Griffin, W. R.: J. Bone Joint Surg. 54A:1712, 1972. 22. D’Alton, E. J., and Mennen, U.: Instructional Course Article: The position of the radial nerve in the upper arm. S. African Orthop. J. August:32-36, 2003. 23. Davies, F., and Laird, M.: The supinator muscle and the deep radial (posterior interosseous nerve). Anat. Rec. 101:243, 1948. 24. Duchenne, G. B.: Physiology of Motion. Translated and edited by E. B. Kaplan. Philadelphia, J. B. Lippincott Co., 1949. 25. El-Hadidi, S., and Burke, F. D.: Posterior interosseous nerve syndrome caused by a bursa in the vicinity of the elbow. J. Hand Surg. 12B:23, 1987. 26. Evans, E. M.: Rotational deformity in the treatment of fractures of both bones of the forearm. J. Bone Joint Surg. 27:373, 1945. 27. Eycleshymer, A. C., and Schoemaker, D. M.: A CrossSection Anatomy. New York, D. Appleton, 1930. 28. Field, J. H.: Posterior interosseous nerve palsy secondary to synovial chondromatosis of the elbow joint. J. Hand Surg. 6:336, 1981. 29. Gardner, E.: The innervation of the elbow joint. Anat. Rec. 102:161, 1948. 30. Grant, J. C. B.: Atlas of Anatomy, 6th ed. Baltimore, Williams & Wilkins, 1972. 31. Gray, H.: In Warwick, R., and Williams, P. L. (eds.): Anatomy, Descriptive and Applied, 35th ed. Philadelphia, W. B. Saunders Co., 1980, p. 429. 32. Greenbaum, B., Itamura, J., Vangsness, C. T., Tibone, J., and Atkinson, R.: Extensor carpi radialis brevis. An

Chapter 2 Anatomy of the Elbow Joint

33. 34.

35. 36.

37. 38. 39.

40. 41.

42. 43.

44.

45.

46. 47. 48.

49. 50.

51.

52. 53. 54.

anatomical analysis of its origin. J. Bone Joint Surg. 81B:926, 1999. Gruber, W.: Monographie der bursae mucosae cubitales. Mem. Acad. Sc. Petersburg VII:10, 1866. Gruber, W.: Monographie Les Canalis Supracondylaideus Humeri. Mem. Acad. Sc. Petersburg. Cited by Morris, H.: Human Anatomy, 3rd ed. Philadelphia, Blakiston, 1953, p. 214. Hamilton, A. T., and Raleigh, N. C.: Subcutaneous rupture of the brachioradialis muscle. Surgery 23:806, 1948. Henle, J.: Handbuch Der Systematischen Anatomie des Menschen Muskellehre. Berlin, Braunschweig, 1866, p. 224. Henry, A. K.: Extensile Exposure, 2nd ed. Baltimore, Williams & Wilkins, 1966. Hollinshead, W. H.: The back and limbs. In Anatomy for Surgeons, Vol. 3. New York, Harper & Row, 1969, p. 379. Jamieson, R. W., and Anson, B. J.: The relation of the median nerve to the heads of origin of the pronator teres muscle: a study of 300 specimens. Q. Bull Northwestern Univ. Med. School 26:34, 1952. Johansson, O.: Capsular and ligament injuries of the elbow joint. Acta Chir. Scand. (Suppl.) 287, 1962. Wadia, F., Kamineni, S., Dhotare, S., and Amis, A: Radiographic measurements of normal elbows: clinical relevance to olecranon fractures. Clin. Anat. 20:407, 2007. Kapandji, I. A.: The Physiology of Joints. Vol. I: Upper Limb, 2nd ed. Baltimore, Williams & Wilkins, 1970. Keats, T. E., Teeslink, R., Diamond, A. E., and Williams, J. H.: Normal axial relationships of the major joints. Radiology 87:904, 1966. Kocher, T.: Textbook of Operative Surgery, 3rd ed. Translated by H. J. Stiles and C. B. Paul. London, A. & C. Black, 1911. Kolb, L. W., and Moore, R. D.: Fractures of the supracondylar process of the humerus. J. Bone Joint Surg. 49A:532, 1967. Langman, J., and Woerdeman, M. W.: Atlas of Medical Anatomy. Philadelphia, W. B. Saunders Co., 1976. Lanz, T., and Wachsmuth, W.: Praktische Anatomie. ARM, Berlin, Springer, 1959. Linell, E. A.: The distribution of nerves in the upper limb, with reference to variables and their clinical significance. J. Anat. 55:79, 1921. Lipmann, K., and Rang, M.: Supracondylar spur of the humerus. J. Bone Joint Surg. 48B:765, 1966. Loomis, L. K.: Reduction and after-treatment of posterior dislocation of the elbow: With special attention to the brachialis muscle and myositis ossificans. Am. J. Surg. 63:56, 1944. Malkawi, H.: Recurent dislocation of the elbow accompanied by ulnar neuropathy: a case report and review of the literature. Clin. Orthop. 161:170, 1981. Martin, B. F.: The annular ligament of the superior radial ulnar joint. J. Anat. 52:473, 1958. Martin, B. F.: The oblique cord of the forearm. J. Anat. 52:609, 1958. McCormick, L. J., Cauldwell, E. W., and Anson, B. J.: Brachial and antebrachial artery patterns: a study of 750 extremities. Surg. Gynecol. Obstet. 96:43, 1953.

37

55. Monro, A.: A Description of All the Bursae Mucosae of the Human Body. London, 1788. Translated into German by J. C. Rosenmutter (Leipzig, 1799). 56. Morrey, B. F., and An, K. N.: Functional anatomy of the elbow ligaments. Clin. Orthop. 201:84, 1985. 57. Morrey, B. F., Askew, L., An, K. N., and Dobyns, J.: Rupture of the distal tendon of the biceps brachii. J. Bone Joint Surg. 67A:418, 1985. 58. Morrey, B. F., and Chao, E. Y.: Passive motion of the elbow joint. A biomechanical analysis. J. Bone Joint Surg. 58A:501, 1976. 59. Morrey, B. F., Tanaka, S., and An, K. N.: Valgus stability of the elbow. A definition of primary and secondary constraints. Clin. Orthop. 265:187, 1991. 60. Morris, H.: In Schaeffer J. P. (ed.): Human Anatomy, 11th ed. Philadelphia, Blakiston, 1953. 61. Nazarian, L. N., McShane, J. M., Ciccotti, M. G., O’Kane, P. L., and Harwood, M. I.: Dynamic US of the anterior band of the ulnar collateral ligament of the elbow in asymptomatic major league baseball pitchers. Radiology 227:149, 2003. 62. Ochi, N., Ogura, T., Hashizume, H., Shigeyama, A. Y., Senda, M., and Inoue, H.: Anatomic relation between the medial collateral ligament of the elbow and the humero-ulnar joint axis. J. Shoulder Elbow Surg. 8:6, 1999. 63. O’Driscoll, S. W., Bell, D. F., and Morrey, B. F.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991. 64. O’Driscoll, S. W., Horii, E., Carmichael, S. W., and Morrey, B. F.: The cubital tunnel and ulnar neuropathy. J. Bone Joint Surg. 73B:613, 1991. 65. O’Driscoll, S. W., Horii, E., and Morrey, B. F.: Anatomy of the attachment of the medial ulnar collateral ligament. J. Hand Surg. 17:164, 1992. 66. O’Driscoll, S. W., Horii, E., Morrey, B. F., and Carmichael, S. W.: Anatomy of the ulnar part of the lateral collateral ligament of the elbow. Clin. Anat. 5:296, 1992. 67. Osgood, R. B.: Radiohumeral bursitis, epicondylitis, epicondylalgia (tennis elbow). Arch Surg. 4:420, 1922. 68. Pankovich, A. M.: Anconeus approach to the elbow joint and the proximal part of the radius and ulna. J. Bone Joint Surg. 59A:124, 1977. 69. Paraskevas, G., Papadopoulos, A., Papaziogas, B., Spanidou, S., Argiriadou, H., and Gigis, J.: Study of the carrying angle of the human elbow joint in full extension: a morphometric analysis. Surg. Radiol. Anat. 26:19, 2004. 70. Polonskaja, R.: Zur frage der arterienanastomosen im gobiete der ellenbagenbeuge des menschen. Anat. Anz. 74:303, 1932. 71. Reimann, A. F., Daseler, E. H., Anson, B. J., and Beaton, L. E.: The palmaris longus muscle and tendon: a study of 1600 extremities. Anat. Rec. 89:495, 1944. 72. Seki, A., Olsen, B. S., Jensen, S. L., Eygendaal, D., and Sojbjerg, J. O.: Functional anatomy of the lateral collateral ligament complex of the elbow: configuration of Y and its role. J. Shoulder Elbow Surg. 11:53, 2002. 73. Shiba, R., Siu, D., and Sorbie, C.: Geometric analysis of the elbow joint. J. Orthop. Res. 6:897, 1988.

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74. Sorbie, C., Shiba, R., Siu, D., Saunders, G., and Wevers, H.: The development of a surface arthroplasty for the elbow. Clin. Orthop. 208:100, 1986. 75. Spalteholz, V.: Hand Atlas of Human Anatomy, 2nd ed. Edited and translated by L. F. Baker. Philadelphia, J. B. Lippincott Co., 1861. 76. Spinner, M., and Kaplan, E. B.: The quadrate ligament of the elbow: its relationship to the stability of the proximal radio-ulnar joint. Acta Orthop. Scand. 41:632, 1970. 77. Steindler, A.: Kinesiology of the Human Body, 5th ed. Springfield, IL, Charles C Thomas, 1977. 78. Stimson, H.: Traumatic rupture of the biceps brachii. Am. J. Surg. 29:472, 1935. 79. Strachan, J. H., and Ellis, B. W.: Vulnerability of the posterior interosseous nerve during radial head resection. J. Bone Joint Surg. 53B:320, 1971. 80. Tanaka, S., An, K. N., and Morrey, B. F.: Kinematics of ulnohumeral joint in simulated active elbow motion. Submitted for publication. 81. Terry, R. J.: New data on the incidence of the supracondylar variation. Am. J. Phys. Anthropol. 9:265, 1926.

82. Thepaut-Mathieu, C., and Maton, B.: The flexor function of the m. pronator teres in man: a quantitative electromyographic study. Eur. J. Appl. Physiol. 54:116, 1985. 83. Thomas, T. T.: A contribution to the mechanism of fractures and dislocations in the elbow region. Ann. Surg. 89:108, 1929. 84. Thompson, H. C., III, and Garcia, A.: Myositis ossificans: aftermath of elbow injuries. Clin. Orthop. 50:129, 1967. 85. Tillman, B.: A Contribution to the Function Morphology of Articular Surfaces. Translated by G. Konorza. Stuttgart, Georg Thieme, P. S. G. Publishing, 1978. 86. Trotter, M.: Septal apertures in the humerus of American whites and negros. Am. J. Phys. Anthropol. 19:213, 1934. 87. Tubbs, R. S., Oakes, W. J., and Salter, E. G.: The subanconeus muscle. Folia Morphol. (Warsz.) 65:22, 2006. 88. Yilmaz, E., Karakurt, L., Belhan, O., Bulut, M., Serin, E., and Avci, M.: Variaton of carrying angle with age, sex, and special reference to side. Orthopedics 28:1360, 2005. 89. Yamaguchi, K., Sweet, F. A., Bindra, R., Morrey, B. F., and Gelberman, R. H.: The extraosseous and intraosseous arterial anatomy of the adult elbow. J. Bone Joint Surg. 79A:1653, 1997.

Chapter 3 Biomechanics of the Elbow

CHAPTER

3

Biomechanics of the Elbow Kai-Nan An, Mark E. Zobitz, and Bernard F. Morrey

INTRODUCTION Upper extremity use depends largely on a functional elbow joint. A complex joint, the elbow serves as a link in the lever arm system that positions the hand, as a fulcrum of the forearm lever, and as a load-carrying joint. Mobility and stability of the elbow joint are necessary for daily, recreational, and professional activities. Loss of function in the elbow, possibly more than that in any other joint, can jeopardize individual independence. In our practice, a working knowledge of biomechanics has been extremely important and rewarding. Clinical relevance includes elbow joint design and technique, the rationale and execution of trauma management, and ligament reconstruction. In short, a clear understanding of biomechanics provides a scientific basis for clinical practice.5 From the clinician’s perspective, we have found the topic of elbow mechanics best discussed according to motion (kinematics), stability (constants), and strength (force transmission).

KINEMATICS The elbow is described as a trochoginglymoid joint. That is, it possesses 2 degrees of freedom (motion): flexionextension and supination-pronation. The articular components include the trochlea and capitellum on the medial and lateral aspects of the bifurcated distal humerus, and distally the upper end of the ulna and the head of the radius. Thus, the joint is composed of three articulations: the radiohumeral, the ulnohumeral, and the radioulnar.

FLEXION-EXTENSION Because of the congruity at the ulnohumeral articulation and surrounding soft tissue constraint, elbow joint motion is considered primarily a hinge type. Yet, two

39

separate three-dimensional studies of passive motion at the elbow revealed that the elbow does not function as a simple hinge joint.51,69 The position of the axis of elbow flexion, as measured from the intersection of the instantaneous axis with the sagittal plane, follows an irregular course. A type of helical motion of the flexion axis has been demonstrated.69 This pattern was previously suggested26,50,61 and was attributed to the obliquity of the trochlear groove along which the ulna moves.52 An electromagnetic tracking device that allows a threedimensional measurement of simulated active elbow joint motion reveals the amount of potential varusvalgus and axial laxity that occurs during elbow flexion to average about 3 to 4 degrees. This has been confirmed with more advanced electromagnetic tracking technology.101

CENTER OF ROTATION The axis of motion in flexion and extension has been the subject of many investigations.60 Fischer (1909), using Reuleaux’s technique, found the so-called locus of the instant center of rotation to be an area 2 to 3 mm in diameter at the center of the trochlea (Fig. 3-1).34 Subsequent experiments with the same technique described a much larger locus.32 In a three-dimensional study of passive motion of the elbow joint, the observations of Fischer were confirmed by using the biplanar x-ray technique.69 Based on direct experimental study as well as analytic investigation, Youm and associates109 concluded that the axis does not change during flexionextension. In our study, however, variations of up to 8 degrees in the position of the screw axis from individual to individual have been shown. As seen from below, the axis of rotation is internally rotated 3 to 8 degrees relative to the plane of the epicondyles. In the coronal plane, a line perpendicular to the axis of rotation forms a proximally and laterally opening angle of 4 to 8 degrees with the long axis of the humerus.105 These data, coupled with the clinical information regarding implant loosening, have inspired the development of less constrained but coupled elbow joint replacement designs. It recently has been demonstrated that these designs do function as semiconstrained implants and allow for the normal out-of-plane rotations noted earlier (see Chapter 49).75 From a practical point of view, despite the different findings of various investigators, the deviation of the center of joint rotation is minimal and the reported variation is probably due to limitations in the experimental design. Thus, the ulnohumeral joint could be assumed to move as a uniaxial articulation except at the extremes of flexion and extension. The axis of rotation passes through the center of the arcs formed by the trochlear sulcus and capitellum.56

Part I Fundamentals and General Considerations

40

Y

2.5mm

7.8mm

90 80

110 100 10

70 30 60 50 40

20 120

0

X Z

FIGURE 3-1 Configuration and dimensions of the locus of the instant center of rotation of the elbow. This axis runs through the center of the articular surface, as viewed on both the anteroposterior (AP) and the lateral planes.

The center of rotation can be identified from external landmarks. In the sagittal plane, the axis lies anterior to the midline of the humerus92 and lies on a line that is colinear with the anterior cortex of the distal humerus.69 The coronal orientation is defined by the plane of the posterior cortex of the distal humerus.19 This axis emerges from the center of the projected center of the capitellum and from the anteroinferior aspect of the medial epicondyle (see Fig. 3-1). Similarly, the effect of altering the center of rotation on the kinematics of the forearm has been recently studied. Alterations of as much as 5 mm proximally, distally, anteriorly, or posteriorly have been shown to have only a slight effect on elbow kinematics (Fig. 3-2). This observation has great clinical relevance regarding the design and insertion of prosthetic replacement and articulating external fixation devices.

FOREARM ROTATION The radiohumeral joint, which forms the lateral half of the elbow joint, has a common transverse axis with the elbow joint, which coincides with the ulnohumeral axis during flexion-extension motion. In addition, the radius rotates around the ulna, allowing for forearm rotation or supination-pronation. In general, the longitudinal

axis of the forearm is considered to pass through the convex head of the radius in the proximal radioulnar joint and through the convex articular surface of the ulna at the distal radioulnar joint.34,97 The axis therefore is oblique to the longitudinal axes of both the radius and the ulna (Fig. 3-3), and rotation is independent of elbow position.45 Mori has characterized the axis of forearm rotation as passing through the attachment of the interosseous membrane at the ulna in the distal fourth of the forearm (see Fig. 3-32).62 This may have particular applications with regard to the sensitivity of forearm rotation to angular deformity in this particular portion of the bone. Clinically and experimentally, less than 10% angulation of either the radius or the ulna causes no functionally significant loss of forearm rotation.91 In the past, ulnar rotation was described as being coupled with forearm rotation.106 This observation could not be reproduced in a subsequent study by Youm and associates.108 By using a metal rod introduced transversely into the ulna, extension, lateral rotation, and then flexion of the ulna was described with rotation from pronation to supination. The axial rotational movements of the ulna were also observed by others.14,22,30,43,69,88,108 Ray and associates88 also suggested that varus-valgus movement of the ulna occurs if the forearm rotates on an axis extending from the head of the radius to the index finger. Experiments from our laboratory76 have demonstrated external axial rotation of the ulna with forearm supination. Internal rotation or closure of the lateral ulnohumeral joint occurs with pronation. Finally, the radius has been shown to migrate 1 to 2 mm proximally with pronation.67 This observation had not been reported previously but has been confirmed by observations at the wrist.82

CARRYING ANGLE The carrying angle is defined as that formed by the long axis of the humerus and the long axis of the ulna. It averages 10 to 15 degrees in men and is about 5 degrees greater in women.1,18,53,97 However, uncertainty has arisen over the use of the term carrying angle in the dynamic setting. Dempster27 described an oscillatory pattern during elbow flexion, whereas Morrey and Chao69 reported a linear change, with the valgus angle being the greatest at full extension and diminishing during flexion. The confusion arises because three descriptions based on different reference systems have been adopted for the measurement of carrying angle changes. Definition 1 The carrying angle is the acute angle formed by the long axis of the humerus as the long axis

Chapter 3 Biomechanics of the Elbow

A

= 5mm ANTERIOR AO-OO varus-valgus and axial rotations, Normalized to OO

DO-OO varus-valgus and axial rotations, Normalized to OO 4 2 0 –2 –4 –6

3 2 1 0 –1 –2 –3

B FIGURE 3-2

0

50

100

3 2 1 0 –1 –2 –3

150

20

0

40

60

80

100

Flexion

Flexion

DO-OO/vrvl DO-OO/irer

AO-OO/vrvl AO-OO/irer

120

140

PROXIMAL

POSTERIOR

PRO-OO varus-valgus and axial rotations, Normalized to OO

PO-OO varus-valgus and axial rotations, Normalized to OO

0

50

100 Flexion PRO-OO/vrvl PRO-OO/irer

150

Degrees, Varus, ER(-) /Valgus, IR(+)

Degrees, Varus, ER(-) /Valgus, IR(+)

Degrees, Varus, ER(-) /Valgus, IR(+)

DISTAL

4 2 0 –2 –4 –6

0

50

100

150

Flexion PO-OO/vrvl PO-OO/irer

Experimental data using the electromagnetic tracking system reveals 5-mm changes in the elbow axis site (A) and causes relatively small effects in the kinematics of the forearm (B).

41

42

Part I Fundamentals and General Considerations

of the ulna projects on the plane containing the humerus (Fig. 3-4A).

Proximal radial-ulnar joint

Definition 2 The carrying angle is described as the acute angle formed by the long axis of the ulna and the projection of the long axis of the humerus onto the plane of the ulna (see Fig. 3-4B).

Ulna

Radius

Distal radial-ulnar joint

FIGURE 3-3

The longitudinal axis of pronationsupination runs proximally from the distal end of the ulna to the center of the radial head. The axis is at the ulnar cortex in the distal one third of the forearm.

Definition 3 The carrying angle is defined analytically as the abduction-adduction angle of the ulna with respect to the humerus when eulerian angles are being used to describe arm motion. From an anatomic point of view, it is not difficult to conclude that the existence of the carrying angle is due to the existence of obliquities, or cubital angles, between the proximal humeral shaft, the trochlea, and the distal ulnar shaft. By assuming that the ulnohumeral joint is a pure hinge joint and that the axis of rotation coincides with the axis of the trochlea, the change in the carrying angle during flexion can be defined as a function of anatomic variations of the obliquity of the articulations according to simple trigonometric calculations.8 If the first or second definition is accepted, the carrying angle changes minimally during flexion. The specific varus/ valgus relationship of the forearm to the humerus during flexion therefore depends on the relative angular relationship of the humeral and ulnar articulations (Fig. 3-5).

FIGURE 3-4

A

B

A, Carrying angle between the humerus and the ulna as measured by viewing from the direction perpendicular to the plane containing the humeral and the flexion axes. Conventionally, the acute angle instead of the obtuse angle shown is used as the carrying angle measurement. B, Carrying angle between humerus and ulna as measured by viewing from the direction perpendicular to the plane containing the ulnar and flexion axes. Conventionally, the acute angle instead of the obtuse angle shown is based as the carrying angle measurement. (From An, K. N., Morrey, B. F., and Chao, E. Y. S.: Carrying angle of the human elbow joint. J. Orthop. Res. 1:369, 1984.)

Chapter 3 Biomechanics of the Elbow

30°

43

30°

FIGURE 3-6

The distal humeral forward flexion is complemented by a 30-degree posterior rotation of the opening of the greater sigmoid notch. (With permission, Mayo Foundation.)

A

B

FIGURE 3-5

The positional relationship of the forearm referable to the humerus in the frontal plane of the humerus (carrying angle) is dependent on the relative tilt of the humeral and ulnar articulations referable to their long axes.

RESTRICTION OF MOTION In normal circumstances, elbow flexion ranges from 0 degrees or slightly hyperextended to about 150 degrees in flexion. Forearm rotation averages from about 75 degrees (pronation) to 85 degrees (supination) (see Chapter 2). The cartilage of the trochlea forms an arc of about 320 degrees, whereas the sigmoid notch creates an arc of about 180 degrees. Generally, the arc of the radial head depression is about 40 degrees,97 which articulates with the capitellum, presenting an angle of 180 degrees. The significance of the 30-degree anterior angulation of the trochlea with the 30-degree posterior orientation of the greater sigmoid notch to flexion and extension and stability of the elbow joint is discussed in detail in Chapter 1 (Fig. 3-6). Impact of the olecranon process on the olecranon fossa and the tension of the anterior ligament and the flexor muscles as well as tautness of the anterior bundle of the medial collateral ligament have been described as serving as a check to extension.40,52 The anterior muscle bulk of the arm and forearm, along with contraction of the triceps, is also reported to prevent active flexion beyond 145 degrees.52 However, the factors limiting passive flexion include the impact of the head of the radius against the radial fossa, the impact of the coronoid process against the coronoid fossa, and tension from the capsule and triceps. For pronation and supination, Braune and Flugel20 found that passive resistance of the stretched antagonist

muscle restricts the excursion range more than that of the ligamentous structures. Spinner and Kaplan,96 however, have shown that the quadrate ligament does provide some static constraint to forearm rotation. Impingement of tissue restrains pronation, especially by the flexor pollicis longus, which is forced against the deep finger flexors. The entire range of active excursion in an intact arm is about 150 degrees, whereas when the muscles are removed from a cadaver specimen, the range increases to 185 to 190 degrees. With cutting the ligaments, the range increased up to 205 to 210 degrees.

CAPACITY AND CONTACT AREA OF THE ELBOW JOINT The capacity of the elbow joint recently has been shown to average about 25 mL. The maximum capacity is observed to occur with the elbow at about 80 degrees of flexion.78 This explains the clinical observation that stiff elbows tend to have fixed deformities at about 80 to 90 degrees of flexion.63 Accurate measurement of the contact points of the elbow is extremely difficult, and several techniques have been applied to this highly congruous joint.99 Silicone casting, Fuji Prescale film, and reversible cartilage staining are most commonly used. Each has advantages and disadvantages. The contact area of the articular surface during elbow joint motion has been investigated by Goodfellow and Bullough, using a staining technique.39 They found that the central depression of the radial head articulates with the dome of the capitellum and that the medial triangular facet was always in contact with the ulna. The upper rim of the radial head made no contact at all. At the humeroulnar joint, the articular surfaces were always in contact during some phases of movement. Others have verified these observations.107 The contact areas on the ulna occurred anteriorly and pos-

44

Part I Fundamentals and General Considerations

teriorly and tended to move together and slightly inward from each side from 0 to 90 degrees of flexion and with increasing load.31,74 Using a wax casting technique, in full extension, the contact has been observed to be on the lower medial aspect of the ulna, whereas in other postures, the pressure areas described a strip extending from posterolateral to anteromedial.37 The radiocapitellar joint also revealed contact during flexion without externally applied load. Investigations in our laboratory show that the contact areas of the elbow occur at four facets: two at the coronoid and two at the olecranon (Fig. 3-7). Only a slight increase in total surface area occurred with elbow flexion and with a sevenfold increase in load.99 With a 10-N load, about 9% contact of the articular surfaces occurs, and with 1280 N, the area increased to about 73%.31

Degrees flexion 0° 90° Medial

FIGURE 3-7

Contact in the sigmoid fossa moves toward the center of the fossa during elbow flexion. (Redrawn from Walker, P. S.: Human Joints and Their Artificial Replacements. Springfield, IL, Charles C. Thomas, 1977.)

When varus and valgus loads are applied to the forearm, the contact changes medially and laterally. This implies a pivot point about which the radioulnar articulation rotates on the humerus in the anteroposterior (AP) plane in extension with varus and valgus stress. In vivo experiments have demonstrated the varus-valgus pivot point of the elbow to reside in the midpoint of the lateral face of the trochlea (Fig. 3-8).

ELBOW STABILITY The elbow is one of the most congruous joints of the musculoskeletal system and, as such, is one of the most stable. This feature is the result of an almost equal contribution from the soft tissue constraints and the articular surfaces. The static soft tissue stabilizers include the collateral ligament complexes and the anterior capsule. Studies from our laboratory regarding the anatomy of the lateral collateral ligament68,77 and others36,79,95 have been discussed previously (see Chapter 2). The lateral collateral ligament and the anterior bundle of the medial collateral ligament originate from points through which the axis of rotation passes. Furthermore, the medial collateral ligament has two discrete components.66,93 The anterior bundle has been shown to be taut in extension; the converse is true for the posterior fibers of the anterior bundle. Because elbow joint motion occurs about a nearly perfect hinge axis through the center of the capitellum and trochlea, the posterior bundle of the medial collateral ligament complex will be taut at different positions of elbow flexion (Fig. 3-9). The lateral collateral ligament and the anterior bundle lying on the axis of rotation will assume a rather uniform tension, regardless of elbow position. Furthermore, the lateral ulnar collateral ligament has inserts on the ulna

FIGURE 3-8

The line of action in the muscles produces a compression force at the radial head when situated just lateral to the middle of the lateral face of the trochlea, and a tension force on the radial head is situated just medial to this point. This indicates that the varus-valgus pivot point in the elbow lies at that point on the AP plane. (From Morrey, B. F., An, K. N., and Stormont, T. J.: Force transmission through the radial head. J. Bone Joint Surg. [Am.] 70:250-256, 1988.)

Normalized distance: Origin to insertion

Chapter 3 Biomechanics of the Elbow

2

45

A - MCL

FIGURE 3-9 RCL 0 0

20 40 60 80 100 120 140 Elbow joint flexion angle (deg)

The anterior medial collateral ligament remains more taut during elbow flexion than does the posterior segment of the ligament. The radial collateral ligament originates at the axis of rotation for elbow flexion; hence, the ligament has little length variation during flexion and extension. (With permission, Mayo Foundation.)

Radial collateral ligament Annular ligament

Lateral ulnar collateral ligament

FIGURE 3-10

The orientation and attachment of the lateral collateral ligament stabilizes the ulna to resist varus and rotatory stresses just as the medial ligament resists valgus stress.

and, as such, helps to stabilize the lateral ulnohumeral joint (Fig. 3-10).23,66,77,81 In experiments performed in our laboratory, O’Driscoll and associates have demonstrated that the lateral ulnar collateral ligament is essential to control the pivot shift maneuver (see Chapter 4). Further evidence of the contribution of the lateral ligament complex to elbow stability is offered by Søjbjerg and associates.94 These investigators also attributed a major role in varus and valgus stability to the annular ligament. Although our work suggests that the major component in the varus and rotatory stability is the structure termed the lateral ulnar collateral ligament, the parallel findings of these investigators suggest that

the lateral complex is, in fact, a major valgus stabilizer of the elbow joint and functions with or without the radial head.80

ARTICULAR AND LIGAMENTOUS INTERACTION The influence of the ligamentous and articular components on joint stability are usually studied with the use of the materials testing machine by imparting a given and controlled displacement to the elbow.47,65,87 The relative contribution of each stabilizing structure can be demonstrated by sequentially eliminating each element and observing the load recorded by the load cell for the

46

Part I Fundamentals and General Considerations

Intact Radial heat excised

Moment 3 (N-m) 2 1

Varus 3°

2°

1° 1

Source

UCL-cut 1°

2°

3° 4° Valgus

Sensor

2 RCL = Radial collateral lig UCL = Ulnar collateral lig

3 4

Load Displacement

5

A

6 Moment 4 (N-m) 3

Intact RCL-cut Radial heat excised UCL-cut

2 1

Varus 5°

4°

3°

2°

1°

1

1°

2°

3°

4° 5° Valgus

Valgus

Varus

FIGURE 3-12

The arrangement of the electromagnetic tracking device allows varus-valgus stresses applied to the elbow during simulated motion with the flexor and extensor muscles. Real-time simultaneous threedimensional motion of the forearm may be monitored with reference to the humerus.

2 3 4

B

RCL = Radial collateral lig UCL = Ulnar collateral lig Load Displacement

FIGURE 3-11

Force displacement curves demonstrate relative contribution of elements to elbow stability in extension (A) and flexion (B). (From Morrey, B. F., and An, K. N.: Articular and ligamentous contributions to the stability of the elbow joint. Am. J. Sports Med. 11:315, 1983.)

TABLE 3-1 Percent Contribution of Restraining Varus-Valgus Displacement Position

Component

Varus

Valgus

Extension

MCL

—

30

LCL

15

—

Capsule

30

40

Articulation

55

30

MCL

—

55

LCL

10

—

Articulation

75

35

Flexion

constant displacement imparted, usually 2 to 5 degrees95 (Fig. 3-11). A simplified summary of the observations from such an experiment is shown in Table 3-1. In extension, the anterior capsule provides about 70% of the soft tissue restraint to distraction, whereas the medial collateral ligament assumes this function at 90 degrees of flexion. Varus stress is checked in extension equally by the joint articulation (55%) and the soft tissue, lateral collateral ligament, and capsule. In flexion, the articulation provides 75% of the varus stability. Valgus stress in extension is equally divided between the medial collateral ligament, the capsule, and the joint surface. With flexion, the capsular contribution is assumed by the medial collateral ligament, which is the primary stabilizer (54%) to valgus stress at this position. Furthermore, for all practical purposes, the anterior portion of the medial collateral ligament provides virtually all of the structure’s functional contribution. Limitations of this experimental model have resulted in an overestimation of the role of the radial head in

MCL, medial collateral ligament complex; LCL = lateral collateral ligament complex.

resisting valgus load.47,65,90 This has prompted the development of an experimental technique that allows simultaneous and accurate measurement of three-dimensional angular and translational changes under given loading conditions (Fig. 3-12). Using the electromagnetic tracking device, an accurate technique for measuring the function of the articular and capsuloligamentous structures was developed.70 More accurate and relevant data were generated.70 Valgus stability is resisted primarily by the medial collateral ligament. With an intact medial collateral ligament, the radial head does not offer any significant additional valgus constraint. With a released or compromised medial collateral ligament, the radial head does resist valgus stress. This important experiment documents that the radial head is a secondary stabilizer

Chapter 3 Biomechanics of the Elbow

Abduction - deg

20

15

10

R head - MCL

RH+PMCL+AMCL RH+PMCL RH INTACT

5

0

0

20

40

A

60 80 100 Elbow flexon - deg

120

140

25

Abduction - deg

20 15

Radial head contribution

10

MCL

5 0 0

20

40

60

80

100

120

140

Elbow flexion - deg

B

MCL+RH PMCL+AMCL

PMCL Intact

FIGURE 3-13

The stabilizing role of the radial head to valgus stress with the collateral intact resection of the radial head has little effect on valgus stability (A). However, if the medial collateral ligament (MCL) has been sectioned, the absence of a radial head markedly increases valgus displacement (B). The fact that the radial head is important only when the medial collateral ligament is released defines the radial head as the secondary stabilizer against valgus stress.

for resisting valgus stress, whereas the medial collateral ligament is the primary stabilizer against valgus force (Fig. 3-13). In a laboratory investigation, the hyperextension trauma produces lesions of the anterior capsule, the avulsion of proximal insertions of both medial and lateral collateral ligaments.103 The degree of extension increased by 17 degrees and induced significant joint laxity in forced valgus internal-external rotation, but not varus.103 It has been recently observed that the valgus and varus laxity of the elbow is dependent on forearm rotation.86 Increased valgus/varus laxity with forearm pronation, particularly in medial collateral ligament deficient elbows, implies a possible additional factor in throwing kinematics that might put professional baseball pitchers at risk of medial collateral ligament injury due to chronic

47

valgus overload. The forearm rotation should be considered during the clinical examination of elbow instability. The stabilizing effects of monoblock and bipolar designs of radial head replacements in cadaver elbows with a deficient medial collateral ligament were studied.85 The constraint mechanism inherent in the implant design significantly affected the mean valgus laxity. The implants all performed similarly except in neutral forearm rotation, in which the elbow laxity associated with the Judet implant was significantly greater than that associated with the other two implants. Comminuted radial head fractures associated with an injury of the medial collateral ligament can be treated with a radial head implant. However, lengthening and shortening of the radial neck by 2.5 mm significantly alters the kinematics and contact pressure through the radiocapitellar joint in the medial collateral ligamentdeficient elbow104 (Fig. 3-14). Radial neck lengthening caused a significant decrease in varus-valgus laxity and ulnar rotation, with the ulna tracking in varus and external rotation. Shortening caused a significant increase in varus-valgus laxity and ulnar rotation, with the ulna tracking in valgus and internal rotation. Therefore, a radial head replacement should be performed with the same level of concern for accuracy and reproducibility of component position and orientation as is appropriate with any other prosthesis. Total elbow arthroplasty has been a valuable procedure for treating patients with rheumatoid arthritis, post-traumatic arthritis, osteoarthritis, and failed reconstructive procedures of the elbow. The development of elbow prostheses diverged into two general types: linked and unlinked. The main concern with such development of unlinked elbow replacements is instability, which is attributable to numerous factors including prosthesis design, ligament integrity, and position of the prosthesis. A series of laboratory studies have been performed to examine the intrinsic constraint of various total elbow arthroplasty designs, as well as the joint laxity after implantation in cadaveric specimens6 (Fig. 3-15). The contribution of the articular geometry to elbow stability was further evaluated by serial removal of portions of the proximal ulna, as shown in Figure 3-16.13 Valgus stress, both in extension and at 90 degrees of flexion, was primarily (75% to 85%) resisted by the proximal half of the sigmoid notch, whereas varus stress was resisted primarily by the distal half, or the coronoid portion of the articulation, both in extension (67%) and in flexion (60%). As demonstrated in subsequent chapters, the central role of the coronoid to provide elbow stability is emerging. As serial portions of the coronoid are removed, the elbow becomes progressively more unstable. If the radial head has been resected, as little as 25% resection causes elbow subluxation at about 70 degrees of flexion. Our

48

Part I Fundamentals and General Considerations

FIGURE 3-14 Average varus (-) or valgus (+) position of the ulna under different radial neck shortening and lengthening conditions, with the application of valgus (top line) or varus (bottom line) gravitational stress. (From Van Glabbeek, F., Van Riet, R. P., Baumfeld, J. A., Neale, P. G., O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow. J. Bone Joint Surg. [Am.] 86:2629, 2004.)

Pritchard-ERS Capitello-Condylar Sorbie-Questor Souter GSB Norway Coonrad-Morrey Human 0

2

4

6

8

10

12

14

Valgus-varus laxity (degrees)

FIGURE 3-15

Joint laxity for human elbow and with total elbow replacement including the SouterStrathclyde, Sorbie-Questor, Pritchard ERS, Ewald Capitellocondylar, GSB III, Norway Elbow, and Coonrad Morrey implants. (From An, K. N.: Kinematics and constraint of total elbow arthroplasty. J. Shoulder Elbow Surg. 14:168S, 2005.)

preliminary studies indicate at least 50% of the coronoid is necessary for elbow stability if the radial head is removed (Fig. 3-17).

FORCE ACROSS ELBOW JOINT Study of the force across the elbow joint is not an easy task. The analysis can be performed at various degrees of sophistication. It can be either two-dimensional or three-dimensional, static or dynamic, with or without the hand activities. The clinical implications of these

forces are obvious, but the magnitudes are not common knowledge. Consequently, in this section, the factors that affect the force passing through the elbow joint will first be analyzed in detail based on two-dimensional considerations. Then, more realistic data based on threedimensional analysis will be presented.

TWO-DIMENSIONAL ELBOW FORCE ANALYSIS In sagittal plane motion, the elbow joint is assumed to be a hinge joint. Forces and moments created at the joint, due to the loads applied at the hand, are balanced by

Chapter 3 Biomechanics of the Elbow

49

= components in x and y direction for the unit vector along the line of action of muscle; Rx, Ry = x and y components of the joint contact force; P, Px, Py = magnitude of the applied forces on the forearm and its associated components; and ri, rp = moment arms of the muscle force and the applied force to the elbow joint center, respectively

fxi, fyi

Combined elbow stability (% of intact)

100 80 25 75 50 100

60 40 20

Elbow angle 0 90

0 25

50

75

100

Excision of proximal ulna (% osteotomy)

FIGURE 3-16

Removal of successive portions of the proximal ulna was studied for its effect on various modes of joint stability. A linear decrease of combined stability is observed, with removal of the olecranon. Note a similar effect for both the extended and the 90degree flexed positions. 100 Elbow stability

50% Coronoid resection 90 60 30 Radial head resection

0 0

15

30

45

60

75

90

105

120

Single-Muscle Analysis

Elbow flexion

FIGURE 3-17

Ulnohumeral instability increases as increasing amounts of coronoid are removed. Resection of 50% of the coronoid can still be stable, but not if the radial head is excised.

the muscles, tendons, ligaments, and contact forces on the articular surfaces. The amount of tension in the muscles and the magnitude and direction of the joint forces are determined by the external loading conditions as well as the responses of muscles-that is, force distribution among these muscles. To calculate these forces, a free-body analysis of the forearm and hand isolated at the elbow joint is required. From this analysis, a set of equilibrium equations is obtained: Σ | Fi | fxi + Rx + Px = 0 Σ | Fi | fyi + Ry + Py = 0 Σ | Fi | · ri + P · rp = 0

The lines of action of muscles crossing the joint have been reported.2,8,84 In the sagittal plane, based on the magnitude of moment arms, the major elbow muscles consist of biceps, brachialis, brachioradialis, extensor carpi radialis longus, triceps, and anconeus (Table 3-2). The other forearm muscles for the hand and wrist provide various but limited contributions to elbow flexion-extension. Unfortunately, the contributions of these forearm muscles are not consistently reported in the literature. Assuming that friction and ligament forces are negligible, the resultant joint constraint force vector should be perpendicular to the arc of the articular surface and pass through the center of curvature of this arc. Thus, the problem of elbow force analysis may be reduced to one of solving the unknown variables Rx, Ry, and | Fi | in equation [1]. However, in reality, even for a simple task, multiple muscles are involved, making the force calculation an indeterminate problem. Methods for resolving these indeterminate problems are thus required.

[1]

in which | Fi | = magnitude of the tension in ith muscle;

The simplest case is to consider only one single muscle involved in resisting external force. This type of consideration has been used widely in the literature for twodimensional force analysis of the musculoskeletal system. The magnitude of the muscle force, f, and the magnitude and orientation of the joint reaction force, R, can be obtained by solving equation [1] with i = 1. f=

rp M d = cos ψ + sin ψ P rf rf R 2 = f + 2f cos (θ + ψ ) + 1 P f sin θ − sin ψ φ = tan −1 f cos θ + cos ψ

[2]

where ψ, θ and φ are the angles between the forearm axis and the applied force, P, muscle pull, M, and resultant joint force, R, respectively. Thus, an intimate relationship between the joint force and muscle forces in balancing the externally applied force on the forearm (Table 3-3) exists. The magnitude of muscle force required for balancing the external force reflects the changes of the muscle’s moment arm, or

Part I Fundamentals and General Considerations

50

TABLE 3-2 Physiologic Cross-Sectional Area (PCSA), Unit Force Vector (Fx, Fy), and Moment Arm (r) of Elbow Muscles in Sagittal Plane ELBOW JOINT FLEXION ANGLE (DEGREE) 0 DEGREES Muscle

PCSA*

30 DEGREES

90 DEGREES

120 DEGREES

r†

Fx

Fy

r

Fx

Fy

r

Fx

Fy

r

Fx

Fy

BIC

4.6

20.7

.86

.50

20.7

.86

.50

45.5

.17

.99

40.0

.35

.93

BRA

7.0

15.2

.82

.57

15.2

.82

.57

33.5

.36

.92

33.8

.12

.97

BRD

1.5

30.8

.99

.11

30.8

.99

.04

75.0

.92

.39

79.9

.89

.41

FCR

2.0

2.0

1.0

.04

2.0

1.0

.04

5.0

1.0

.04

5.9

1.0

.04

ECRL

2.4

8.6

.99

.16

8.6

.99

.16

29.3

.97

.25

32.0

.97

.26

FCU

1.6

0.0

1.0

.04

0.0

.99

.04

0.0

1.0

.04

0.0

1.0

.04

TRI

18.8

23.0

1.0

.09

26.0

.81

.59

20.0

.05

1.0

17.0

.05

1.0

ECRB

1.5

1.0

.99

.17

1.0

.99

.17

2.0

.96

2.8

2.5

.96

.28

ECU

1.7

2.0

.99

.16

9.0

.99

.16

9.0

.98

.19

8.0

.98

.19

EDC

3.8

0.0

.99

.17

0.0

.99

.17

2.0

.98

.22

2.0

.99

.23

FDS

3.0

4.0

1.0

.04

3.0

1.0

.05

3.5

1.0

.04

3.5

1.0

.04

BIC, biceps; BRA, brachialis; BRD, brachioradialis; ECRB, extensor carpi radialis brevis; ECRL, extensor carpi radialis longus; ECU, extensor carpi ulnaris; EDC, extensor digitorum communis; FCR, flexor carpi radialis; FCU, flexor carpi ulnaris; FDS, flexor digitorum superficialis; TRI, triceps. *PCSA = cm2. † r = mm. M2

M1

M3

mechanical advantage, with changes of the joint configuration.

Effect of Muscle Moment Arm + P

R1 +

R2 R

3

FIGURE 3-18

Effect on the muscle and joint forces by changing the moment arm of the muscle force. For a given externally applied force, the longer moment arm decreases the muscle and joint forces. Also, the resultant joint force and orientation (R1, R2, R3) are affected by the magnitude of the muscle moment arm.

The effect of a changing muscle moment arm on the resultant joint force is demonstrated graphically in Figure 3-18. If the loading configuration does not change, both the muscle force and the joint reaction force decrease as the muscle moment arm increases. The orientation of the resultant force also changes from the middle portion of the trochlear notch toward the border of the articular cartilage. Clinically, the concept of increasing the moment arm of the biceps muscle by moving the insertion distally has been adopted for increasing weak flexion force of the elbow in patients with brachial plexus injury.72

Effect of Orientation on Muscle Line of Action Under the same loading condition, the effect of changing the orientation of the muscle line of action under a constant moment arm is demonstrated (Fig. 3-19). The applied force is again assumed to be perpendicular to the forearm. Both magnitudes of muscle and joint reaction forces change slightly with the change of the muscle’s line of action. However, the orientation of the resultant joint force is sensitive to changes in the muscle force line. The orientation of the resultant joint force, therefore, moves from the central portion of the trochlea toward

Chapter 3 Biomechanics of the Elbow

51

Muscle and Joint Forces with Single Muscle*

TABLE 3-3

ELBOW JOINT FLEXION ANGLE (DEGREE) 0 DEGREES

30 DEGREES

90 DEGREES F/P

120 DEGREES

F/P

R/P

φ

F/P

R/P

φ

R/P

φ

F/P

R/P

φ

BIC

15.5

15.5

27.0

15.5

15.0

27.0

7.0

6.1

78.7

8.0

7.1

66.4

BRA

21.1

20.5

32.0

21.1

20.5

32.0

9.6

8.6

66.3

9.5

8.5

82.6

BRD

10.4

10.4

3.2

10.4

10.4

3.2

4.3

4.0

9.6

4.0

3.7

10.5

TRI

13.9

14.5

39.3

12.3

12.9

39.7

16.0

17.0

87.3

18.8

19.8

87.2

BIC, biceps; BRA, bracialis; BRD, brachioradialis; F, muscle force; P, applied force; R, resultant joint force TRI, triceps. *rp, 320 mm; D, 15 mm; ψ, 90 degrees for flexion; ψ, 270 degrees for extension. φ, angle between R and long ulnar axis.

M2 M1

+

P

R1 + R2

FIGURE 3-19

Effect of changing the orientation of the muscle line of action on the muscle and joint force under a given load. The magnitudes of both muscle and joint forces are not changed, but their orientations are.

the rim as the direction of muscle pull relative to the forearm changes from vertical to parallel. This is especially true for the resultant joint force in the trochlear notch brought about by the contraction of the upper arm muscles, whose direction relative to the forearm axis changes with the elbow joint flexion angle. On the other hand, the directions of forearm muscles with respect to the resultant joint forces are thus reasonably constant. When considering the direction of resultant joint forces applied on the trochlea, the effects of upper arm and forearm muscles are just reversed. These changes have been confirmed and directly measured with a force transducer at the proximal radius and different orientation of the line of action of the flexors and extensors.67

Effect of the Moment Arm of External Force With the orientations and moment arms of the muscles kept constant, the magnitude of muscle force and joint

force created to resist the externally applied force decrease proportionally, with the decrease of the moment arm of the external force. This is true, simply because the resultant segmental moment created at the elbow joint due to externally applied load decreases when the moment arm decreases. It should be noticed that the direction of resultant joint force also changes slightly. From the aforementioned results, it is also easy to realize that the magnitude of the muscle and joint force increases proportionally with increases in the magnitude of external force. Therefore, in general, these results are usually expressed in terms of ratio to the external load.

Effect of the Direction of the Externally Applied Force When the force applied at the wrist changes direction from vertical to horizontal, the effective moment arm of this applied force changes. The resultant segmental moment about the elbow joint center due to this force changes as well (Fig. 3-20). Furthermore, when the resultant segmental moments change from flexion to extension, the required muscles also change from flexors to extensors.

Effect of Change in Axis of Rotation The sensitivity of the muscle moment arm to the axis of rotation is a critically important consideration in the clinical setting. Altering the axis by 1 cm anterior, posterior, proximal, and distally has a surprisingly small effect on the muscle moments at the elbow. Such axis changes result in less than 10% change in muscle moment arm values (Fig. 3-21). In summary, the parametric analysis demonstrates that the magnitude and orientation of the resultant joint forces in the trochlear notch depend very much on whether the upper arm or forearm muscles are used, as well as the location and orientation of the external load applied on the forearm and the joint flexion angle that alters the moment arm and orientation of the muscle

52

Part I Fundamentals and General Considerations

line of action. However, alterations of the flexion axis have little impact on muscle moment arm.

Multiple Muscle Analysis In reality, when external loads are applied on the forearm, multiple muscles are involved, and this makes the ana-

d = 1.5 cm rm = 4.44 cm rp = 32.0 cm θ = 47.3º

ψ = 0º

0º 12 0º 15

3 6 0º 90 0º º

FIGURE 3-20

Effect of changes in the orientation of the applied force (χ), where 90 degrees is perpendicular to the long axis of the forearm.

lytic determination of muscle and joint forces difficult. Because the magnitude and orientation of the resultant joint force are two unknown variables, if more than one muscle force is involved the number of unknown variables exceeds the number of available equations (three). This makes the problem indeterminate, and a nonunique solution will result. Several methods have been employed to resolve the indeterminate problem. Electromyographic (EMG) data and the physiologic cross-sectional area may be used to provide an additional equation.35,49 The most commonly adopted techniques are analytic reduction and optimization methods. In the reduction method, the redundant unknown variables are systematically eliminated, making the remaining system uniquely solvable. In a two-dimensional analysis, this method is more or less the same as that which considers only one single muscle, as described in the previous section. This method can usually provide the ranges of magnitude and orientation of the resultant joint forces for a given task. However, the technique may give physiologically unreasonable solutions, such as using one single forearm muscle to resist the forearm load. Additional judgment and screening are thus required. With the use of the optimization method, a unique solution to an indeterminate problem is obtained by minimizing a preselected objective function or cost function.11 Although the solution to the problem is still nonunique, each solution generally is associated with some physiologic phenomenon or condition on which the objective function is constructed and selected. This technique has been described in more detail elsewhere.9

TRICEPS Moment arm (m)

0.06 0.04 0.02 0 0

50

100

0

50

100

150

–0.019 –0.023 –0.027 Flexion angle (deg)

BRACHIALIS

BRACHIORADIALIS Moment arm (m)

0.03 0.02 0.01 0 0

50

100

Flexion angle (deg)

FIGURE 3-21

150

–0.015

Flexion angle (deg)

Moment arm (m)

Intact Ant Post Prox Dist Abd Add Int Ext

Moment arm (m)

BICEPS

150

0.12 0.08 0.04 0 0

50

100

Flexion angle (deg)

A 1-cm alteration in the axis of flexion shows little effect on muscle moment arms.

150

Chapter 3 Biomechanics of the Elbow

Recently, the results based on various object functions have been compared with EMG data regarding the muscles. The dependence of muscle coordination is related more to the degree of freedom considered, and less to the cost function selected.21 The most commonly used objective functions for resolving the indeterminate force analysis problem include linear and nonlinear weighted combinations of the unknown variables. An analytic model for the determination of muscle force across the elbow joint during isometric loading has been developed.10 In addition to the equilibrium equations obtained from free-body analysis, constraints for muscle tensions based on the physiologic considerations of muscle length-tension and velocity-tension relationships were included: 0 ≤ F ≤ Fˆ · PCSA · σ [3] in which F is the magnitude of muscle tension, Fˆ is the normalized muscle force as adjusted by the muscle length, PCSA represents the muscle physiologic crosssectional area, and σ is the upper bound of muscle activation level. The maximum stress could be generated by the muscle. The word activation is used to describe both the number of active units (recruitment) and their degree of activity (firing frequency). The muscle force distribution was then determined by using the optimization method of minimizing σ

[4]

in which σ is taken as the upper bound value of overall activation of all muscles. In this analysis, the effects of muscle architecture on the muscle force were examined.

Major Elbow Muscles We are now in a position to consider several muscles in the solution; these include biceps, triceps, brachialis, and brachioradialis. TABLE 3-4

53

For the loading case of force applied nonperpendicularly at the wrist, the solutions of two types of optimization procedures are shown in Table 3-4. The magnitude (R) and direction (φ) of the resultant joint forces correspond to various loads. The resultant joint force shows more variation along the articular surface with changes of joint flexion (Fig. 3-22). This is because the line of action of the upper arm muscle undergoes a tremendous change in direction with respect to the ulnar axis during flexion, as discussed earlier. The maximum elbow flexion strength occurs at 90 degrees59,71 (see Chapter 5). From the measured lifting strength data, the maximal muscle force per unit of cross-sectional area can be calculated to be in the range of 10 to 14 kg/cm2. About one third to one half of the maximum lifting force can be generated with the elbow in the extended or 30-degree flexed position. At these positions, a force almost three times the body weight can be encountered in the elbow joint during strenuous lifting at about 30 degrees of flexion (Table 3-5). During strenuous actions, the maximum tension that could possibly be provided by each individual muscle is usually considered to be proportional to the physiologic cross-sectional area. This has been carefully measured for muscles crossing the elbow.8 The potential moment contribution of each muscle at the elbow joint can thus be estimated by multiplying its moment arm by its physiologic cross-sectional area. The moment contributions for all of the muscles crossing the elbow joint have been calculated (Fig. 3-23). Of note, the potential moment in varus appears to be balanced by the valgus moment under all of the functional configurations. When flexed, the flexion potential moment seems to be balanced by the extension moment. However, the extension moment exceeds the flexion moment when the elbow is extended.

Muscle and Joint Forces in Resisting Flexion Moment by Three Major Flexors* OPTIMIZATION METHODS FOR SOLUTIONS (ELBOW JOINT ANGLE = 90 DEGREES) Obj = S (MUSCLE STRESS)2

ψ†

BIC

BRA

BRD

Obj‡ = s ; MUSCLE STRESS £ s R

φ

BIC

BRA

BRD

R

φ

0 degrees

.13

.22

.02

.17

17.0

.12

.19

.04

1.17

5.6

30 degrees

1.49

2.55

.26

4.14

56.5

1.43

2.18

.47

3.89

53.3

60 degrees

2.46

4.19

.43

6.30

63.3

2.35

3.58

.77

5.86

60.3

90 degrees

2.76

4.71

.49

6.83

67.4

2.65

4.03

.86

6.31

64.6

120 degrees

2.33

3.97

.41

5.56

72.1

2.23

3.39

.73

5.10

69.6

150 degrees

1.27

2.17

.22

2.88

83.2

1.22

1.85

.40

2.60

81.7

BIC, biceps; BRA, brachialis; BRD, brachioradialis. *Muscle and joint forces are expressed in the unit of externally applied force. † Angle between the vector of externally applied force and the long ulnar axis (degree). ‡ Most realistic solution based on experimental and analytic considerations (see text).

Part I Fundamentals and General Considerations

54

In constructing these moment potential diagrams, it is assumed that all muscles simultaneously and maximally contract to their optimal lengths. To apply these data for more general conditions, consideration should be given and adjustment made for length-tension and force-velocity relationships. In addition, when activities involve submaximal contraction, a proper scaling system based on experimental measurements, such as EMG,3,28,33,35,61 is required. In more refined models, the

90120 Flexion angle:

90120 Flexion angle: Muscle: BIC, BRA, BRD Method: Obj = σ Muscle force < σ

Muscle: BIC

+

+ 0 30

0,30 90120 Flexion angle:

0 30 90 120

90120 Flexion angle: Muscle: BIC, BRA, BRD Method: Obj = ∑ (Muscle stress)2

Muscle: BRA

+

+ 0 30 90 120

Flexion angle:

Flexion angle:

Muscle: BRD

Muscle: BIC, BRA, BRD Method: Obj = ∑ (Muscle force)2

Extensors EMG investigations of the elbow extensor muscles were first completed by Travill in 1962.102 The medial head of the triceps and anconeus muscles were found to be active during extension; the lateral and long head of the triceps acted as auxiliaries. The anconeus also was active during resisted pronation and supination. In fact, the anconeus has been demonstrated to be active during flexion and abduction-adduction resisted motions.35,83

FIGURE 3-22

Joint force magnitude and direction from an applied load at the wrist at various elbow flexion angles. Family of solutions by using different muscle combinations and solution techniques.

TABLE 3-5

EMG analysis is used to provide scaling systems for the muscle force calculations during submaximal contraction and to show the phasic distribution of muscular activities for a given task.

Surface electrodes along the belly of the biceps were first used100 to record electrical activity during dynamic flexion and extension, with and without load. This early study showed a decrease in biceps activity in pronation compared with supination, and that the biceps acted in extension to “brake” the forearm. Subsequent studies have presented inconsistent data, but in almost all investigations, the biceps demonstrates no16 or decreased activity when flexion occurs in pronation.35,58,98 As expected, little influence is reflected in the brachialis muscle with forearm rotation.35,98 The brachioradialis demonstrates electrical activity with flexion, especially with the forearm rotated to the neutral position17,29 or in pronation.35,54,98 These data are summarized for the 90-degree flexion position, because this is the position of maximum strength15,54 and of greatest electrical activity of the elbow flexors35 (Fig. 3-25).

0 30

0,30

Electromyographic Activities of Elbow Muscles

Flexors

+

+

muscle physiology, including the length-velocity-tension relationship, should be considered.10,38 In an analytic modeling, the effect of distal humeral shortening on the triceps force production and thus the elbow extension strength has been demonstrated48 (Fig. 3-24).

Muscle and Joint Forces Under Maximum Flexion Forces

Elbow Flexion Angle (degree)

Maximum Flexion* Strength at Wrist (newton)

MUSCLE FORCE (¥ BODY WEIGHT) BIC

BRA

BRD

Resultant Joint Force

0

90-150

0.79-1.19

1.2-1.81

0.29-0.39

2.15-3.2

30

110-190

1.00-1.48

1.5-2.26

0.32-0.49

2.70-4.1

90

220-383

0.90-1.33

1.3-2.02

0.29-0.43

2.10-3.1

120

178-307

0.72-1.08

1.1-1.66

0.24-0.31

1.70-2.6

BIC, biceps; BRA, brachialis; BRD, brachioradialis. *Based on average body weight of 150 lb.

Anterior

BIC BRD 8.938 BRA 4.252 7.099 PRO 7.810

ECR 11.978 EDC Lateral 10.131 ECU 7.532

Anterior

cm x cm2

FCR Medial 5.563

Lateral

ANC 3.789

TRI 53.301 Posterior

B

A

BIC 6.076 ECR BRD 16.516 4.164 Lateral

cm x cm2

cm x cm2

Anterior BRA 13.649 BIC

ECR BRD 20.233 7.920

BRA 7.914 PRO 6.683 Medial FCR 4.712 FCU FDS 7.868 13.552

EDC 13.213 ECU 11.630 ANC 3.110

15.907 PRO 17.273

Lateral

FCR 4.596

EDC 12.479

ECU 9.847

FDS 11.737

ANC 4.664

Posterior

C

TRI 34.553 Posterior

D

Anterior

Anterior

EDC 11.966

cm x cm2

BRD BIC 6.173 BRA 16.532 14.331 ECR 15.279

BIC 12.156 BRD 5.619

BRA 9.006

PRO 7.742 FCR 3.747

Lateral ECU 11.761 ANC 6.899

Medial

FCU 5.577

TRI 45.393

ECR 13.262

FDS Medial 12.947 FCR 3.514

FCU 7.126

TRI 48.520 Posterior

Anterior

BIC 8.045

EDC 15.197

FDS FCU 17.908 8.984

ANC 3.692

PRO 5.690

BRA BRD 4.092 5.328

ECR 11.978

cm x cm2

Medial

Lateral

PRO 7.611 FCR 4.789 FDS 11.614

EDC 7.855 ECU 9.911

FDS FCU 10.892 7.063

cm x cm2

Medial

FCU 6.566

ANC 5.199

TRI 51.088 TRI 38.602

Posterior

E

F FIGURE 3-23

Posterior

The potential moment contribution of each muscle at the elbow joint was estimated by multiplying the moment arm (cm) of the muscle by its physiologic cross-sectional area (cm2). These diagrams show the contributions to flexion-extension and varus-valgus rotation about the joint center at six elbow and forearm configurations. A, Extended/supinated. B, Extended/neutral. C, Extended/pronated. D, Semiflexed/neutral. E, Flexed/neutral. (From An, K. N., Hui, F. C., Morrey, B. F., Linscheid, R. L., and Chao, E. Y.: Muscles across the elbow joint: A biomechanical analysis. J. Biomech. 14:659, 1981.)

Part I Fundamentals and General Considerations

56

Strength % normal

100

Trochlea

Humerus

Capitulum

Elbow at 30°

80 60

145º 120º

145º

40 120º 90º 60º

20 0 0

10

20

30º

30

120º

90º

11 .4N 90º 0º

60º

30º

Shortening: Origin-insertion/mm

FIGURE 3-24

Length-tension relationship for the triceps with the elbow at 30 degrees of flexion. FLEXION MUSCLE ACTIVITY ELBOW 90º

Supination

Neutral

12.6N

60º 23.9N

Pronation

30º

0º

0º

FIGURE 3-26

Orientation and magnitude of forces at the humeral articular surface during flexion, per unit of force at the hand. (From Amis, A. A., Dowson, D., and Wright, V.: Elbow joint force predictions for some strenuous isometric actions. J. Biomech. 13:765, 1980.)

and, hence, is considered a dynamic joint stabilizer; and (5) generally speaking, the different heads of the triceps and biceps are active in the same manner through most motion.

Brachialis Biceps Brachiorad. Flex. carpi rad.

Forearm Muscles

Ext. carpi rad. Ext. carpi ulna. Anconeus Triceps 0

100

0

100

0

100

% electrical activity

FIGURE 3-25

Electrical activity of the major elbow flexors at 90 degrees of flexion in different forearm rotation positions. (From Funk, D. A., An, K. N., Morrey, B. F., and Daube, J. R.: Electromyographic analysis of muscles across the elbow joint. J. Orthop. Res. 5:529, 1987.)

Thus, the anconeus may be considered a stabilizer of the elbow joint, being active with almost all motions. In 1972, Currier studied the same muscles at 60, 90, and 120 degrees of elbow flexion. The greatest electrical activity occurred at the 90-degree and 120-degree positions, consistent with the position of greatest strength.24 Others55 found there was no difference between position and muscular electrical activity. EMG data of the elbow muscles have thus provided the following information: (1) the biceps is generally less active in full pronation of the forearm, probably owing to its secondary role as a supinator; (2) the brachialis is active in most ranges of function and is believed to be the “workhorse” of flexion; (3) there is an increase of electrical activity of the triceps with increased elbow flexion, probably secondary to an increased stretch reflex; (4) the anconeus shows activity in all positions

Some of the forearm muscles originating at the medial and lateral aspects of the distal humerus had been considered in stabilizing the elbow joint. Flexor carpi ulnaris and flexor digitorum superficialis muscles, because of their positions and proximities over the medial collateral ligaments, were potentially the muscles best suited to provide medial elbow support.25 However, in the EMG investigations, no significant activities of these muscles were noted when valgus and varus stresses were applied.35 In a recent study of baseball pitchers with medial collateral ligament insufficiency, the data did not demonstrate increased electrical activity of these muscles.42 These findings suggested that the muscles on the medial side of the elbow do not supplement the role of medial collateral ligaments.42

Distributive Forces on the Articular Surfaces Joint compressive forces on various facets of the elbow joint have been reported in the literature.3,73 During the activities of resisting flexion and extension moments at various elbow joint positions, the components of force along the mediolateral direction, causing varus-valgus stress, are small compared with those acting in the sagittal plane directed anteriorly or posteriorly. The resultant joint forces on the trochlea and capitellum have been described in the sagittal plane for flexion (Fig. 3-26) and extension (Fig. 3-27) isometric loads. With the elbow extended and axially loaded, the distribution of stress across the joint has been calculated to be approximately 40% across the ulnohumeral joint and 60% across the

Chapter 3 Biomechanics of the Elbow

Trochlea

Humerus

57

Capitulum

145º

FIGURE 3-27

120º 90º

145º

120º

90º

0º 30º 60º

21N 120º 90º

60º 30º

0º

Applied force

40%

8.6N

60º

12.5N

145º

60%

FIGURE 3-28

Static compression of the extended elbow places more force on the radiohumeral than the ulnohumeral joint.

radiohumeral articulation (Fig. 3-28).41,107 More recently, based on a cadaveric study,46,57 it has been noted that with the elbow in valgus realignment, only 12% of the axial load is transmitted through the proximal end of the ulna, but with the elbow in varus alignment, 93% of the axial force is transmitted to proximal ulna. Because of the poor mechanical advantage with the elbow in extension, the largest isometric flexion forces occur in this position (see Fig. 3-27).3,49 Isometric extension produces a posterosuperior compressive stress across the distal humerus. These analytic calculations have undergone experimental confirmation. Using a force transducer at the proximal radius, the greatest force was

30º

0º

Orientation and magnitude of forces at the humeral articulating surface during extension, per unit of force at the hand. (From Amis, A. A., Dowson, D., and Wright, V.: Elbow joint force predictions for some strenuous isometric actions. J. Biomech. 13:765, 1980.)

transmitted across the radiohumeral joint in full extension, a position in which the muscles have poor mechanical advantage.68 When the elbow is flexed, inward rotation of the forearm against resistance imposes large torque to the joint. The magnitudes have been calculated as approaching twice body weight tension in the medial collateral ligament and three times body weight at the radiohumeral joint.4 Experimental data from the force transducer study suggest that the analytic estimate is probably too high. The greatest force on the radial head from the transducer data occurs with the forearm in pronation (Fig. 3-29). Even in this position, however, the maximum possible force transmission at the radiohumeral joint was measured as approximately 0.9 times the body weight.67 Considerably less knowledge is available regarding the distributed forces at the elbow during use. Nicol and associates73 have demonstrated significant forces with daily activities that not only occur at the radiohumeral and ulnohumeral joints but also are generated in the collateral ligaments. An example of such a force pattern is shown in Figure 3-30. The actual distributive forces occurring at this joint with daily activity constitute an important avenue of further investigation.

Contact Stress on the Joint Articular Surface With the magnitude, direction, and point of application of the resultant joint force available, the stress on the articular cartilage can now be determined.84 Because the joint is not a simple geometric shape, a method based on the concept of a rigid body spring model was adopted for solution.11 In the results, it was found that if the line of action of the resultant force is at the middle of the articular surface, the stress is almost equally distributed throughout the entire articular surface (Fig. 3-31A). On the other hand, as the resultant force is directed toward the margin of the articulation anteriorly or posteriorly, the weight-bearing surface becomes smaller, the maximum compressive stress becomes elevated, and the stress distribution over the joint surface becomes more

58

Part I Fundamentals and General Considerations

A

FIGURE 3-29

Consistently greater force transmission occurs with the forearm in pronation than in supination. This indicates that a screw-hole mechanism exists with the proximal radial migration occurring during this maneuver. (From Morrey, B. F., An, K. N., and Stormont, T. J.: Force transmission through the radial head. J. Bone Joint Surg. [Am.] 70:250, 1988.)

B FIGURE 3-31

The contact pressure depends on the direction and magnitude of the resultant compressive force. A, When the resultant force is oriented toward the center of the trochlear notch, a more uniform distribution of pressure is observed. B, When the line of action of the resultant joint force is directed to the rim of the trochlear notch, the weight-bearing surface becomes smaller, and maximum compressive stresses increases.

tudes and directions of the resultant joint forces, and thus the articulating pressure distribution and joint stability, were extensively examined (Fig. 3-32).7

Finite Element Analysis of Composite Fixation for Total Elbow Prosthesis

FIGURE 3-30

Distribution of articular and soft tissue forces across the elbow for a selected activity. (From Nicol, A. C., Berme, N., and Paul, J. P.: A biomechanical analysis of elbow joint function. In Joint Replacement in the Upper Limb. London, Institute of Mechanical Engineers, 1977, p. 45.)

uneven (see Fig. 3-31B). It should be further noted that the position of maximum stress does not necessarily correspond with the point of intersection of the resultant joint force through the articular surface. Based on this model, the role of antagonistic muscles on the magni-

In total elbow arthroplasty implant loosening remains a challenging complication. Achieving rigid fixation using a combination of bone ingrowth and cementing should improve the implant longevity. The semiconstrained Coonrad-Morrey elbow prosthesis employs this philosophy. It has shown generally satisfactory clinical results for a variety of cases including inflammatory arthritis and distal humerus fracture.44,89 The humeral component of the implant incorporates an anterior flange that has the theoretical benefit of transferring stress from the elbow to the humeral bone and relieving stress concentrations at the vulnerable distal humerus cement interface. Finite element analysis was used to evaluate the biomechanical effects of bone graft between the anterior flange and the bone cortex. Models were created that consisted of the humeral component of the Coonrad/Morrey elbow prosthesis,

Chapter 3 Biomechanics of the Elbow

59

Fm Fe Ff

Flexo

r

Φ

or

Extens

U Θ R

Pm P

24

12

16

24

Θ

R

A

θ

R 8

36

.2

.3

.4

.5

FIGURE 3-32

.6

Fe/Ff 20

25

0 Φ

Pm

20 Pm 15

Φ

–40

10 .2

B

–20

.3

.4

.5

.6

Fe/Ff

bone cement surrounding the implant stem, simulated distal humerus, and bone graft between the distal humerus and anterior flange of the prosthesis. Material properties were prescribed as linear elastic with Poisson ratio of 0.3 and elastic modulus values of implant (E = 114 GPa), humerus (E = 17 GPa), bone cement (E = 3 GPa), and bone graft (E = 0.65 GPa). Perfect bonding between the bone-cement and cement-implant interfaces was assumed. Permutations of the stem size (4, 6, and 8 inch), graft size (50% of flange length, 100% of flange length, and 150% of flange length), and distal humerus (normal and simulated defect) were evaluated. Loading to the implant was applied for cases of anterior (45 N), posterior (45 N), axial (45 N), 45 degrees posterior (45 N), and torsion (1 N-m) load.

A, Pressure distribution on elbow joint surface as external load P is applied at the distal end of the ulna. Distribution of muscle force, Fe and Ff, influences the magnitude, R, and the direction, F, of resultant force on the elbow joint. F represents the “attempted displacement,” U, of the humerus relative to the direction of the ulna. B, For the given loading condition, resultant joint force increased with increasing involvement of extensor muscle, as represented by the ratio of extension force Fe to flexor force Ff (top). Peak articular pressure and the direction of the attempted displacement of the humerus also are affected by the level of involvement of extensor muscle (bottom). (From An, K. N., Himeno, S., Tsumura, H., Kawai, T., and Chao, E. Y.: Pressure distribution on articular surfaces: Application to joint stability evaluation. J. Biomech. 23:1013, 1990.)

Finite element analysis shows that stress and strain in the distal humerus and distal cement mantle can be reduced 10% to 30% when using a bone graft compared with no bone graft between the anterior flange and the bone cortex (Fig. 3-33). Furthermore, when the distal humerus had a simulated defect of 2 cm, extension of the bone graft more proximally than the anterior flange reduced the stress and strain up to 17% compared with bone graft just under the flange. Finally, when selecting the stem size, there was up to a 15% reduction in distal cement stress and strain when choosing a 6-inch stem over a 4-inch stem or when choosing an 8-inch stem over a 6-inch stem. These findings confirmed the clinical experience that rigid fixation and stress relief due to the anterior flange of the implant reduce the complication rate for primary and revision total elbow arthroplasty.

60

Part I Fundamentals and General Considerations

Cement strain ratio

1.00 0.75 0.50 0.25 0.00 Posterior Anterior

B

Torsion no graft

Axial

45 Deg post

graft

FIGURE 3-33 Stress transmission through finite element model of elbow prosthesis before (A) and after (B) placement of bone graft between anterior flange and distal humerus. The bone graft and humerus are cut away to show the internal stress transmission.

References 1. Amis, A. A., Dowson, D., Unsworth A., Miller, J. H., and Wright, V. An examination of the elbow articulation with particular reference to variation of the carrying angle. Eng. Med. 6:76, 1977. 2. Amis, A. A., Dowson, D., and Wright, V.: Muscle strengths and musculoskeletal geometry of the upper limb. Eng. Med. 8:41, 1979. 3. Amis, A. A., Dowson, D., and Wright, V.: Elbow joint force predictions for some strenuous isometric actions. J. Biomech. 13:765, 1980. 4. Amis, A. A., Miller, J. H., Dowson, D., and Wright, V.: Biomechanical aspects of the elbow: Joint forces related to prosthesis design. IEEE Eng. Med. Biol. Mag. 10:65, 1981. 5. An, K. N.: Biomechanics: Basic relevant concepts. Section 1 basic science. In Morrey, B. F. (ed.): Joint Replacement Arthroplasty. New York, Churchill Livingstone, 1991, p. 7. 6. An, K. N.: Kinematics and constraint of total elbow arthroplasty. J. Shoulder Elbow Surg. 14:168S, 2005. 7. An, K. N., Himeno, S., Tsumura, H., Kawai, T., and Chao, E. Y.: Pressure distribution on articular surfaces: Application to joint stability evaluation. J. Biomech. 23:1013, 1990. 8. An, K. N., Hui, F. C., Morrey, B. F., Linscheid, R. L., and Chao, E. Y.: Muscles across the elbow joint: A biomechanical analysis. J. Biomech. 14:659, 1981. 9. An, K. N., Jacobsen, M. C., Berglund, L. J., and Chao, E. Y.: Application of a magnetic tracking device to kinesiologic studies. J. Biomech. 21:613, 1988. 10. An, K. N., Kaufman, K. R., and Chao, E. Y.: Physiological considerations of muscle force through the elbow joint. J. Biomech. 22:1249, 1989. 11. An, K. N., Kwak, B. M., Chao, E. Y., and Morrey, B. F.: Determination of muscle and joint forces: A new technique to solve the indeterminate problem. J. Biomech. Eng. 106:364, 1984. 12. An, K. N., Morrey, B. F., and Chao, E. Y.: Carrying angle of the human elbow joint. J. Orthop. Res. 1:369, 1984.

13. An, K. N., Morrey, B. F., and Chao, E. Y.: The effect of partial removal of proximal ulna on elbow constraint. Clin. Orthop. 209:270, 1986. 14. Anderson, R.: Rotation of the forearm. Lancet 2:1333, 1901. 15. Askew, L. J., An, K. N., Morrey, B. F., and Chao, E. Y.: Isometric elbow strength in normal individuals. Clin. Orthop. 222:261, 1987. 16. Basmajian, J. V., and Latif, S.: Integrated actions and functions of the chief flexors of the elbow. J. Bone Joint Surg. [Am.] 39:1106, 1957. 17. Basmajian, J. V., and Travill, A. A.: Electromyography of the pronator muscles in the forearm. Anat. Rec. 139:45, 1961. 18. Beals, R. K.: The normal carrying angle of the elbow. A radiographic study of 422 patients. Clin. Orthop. 119:194, 1976. 19. Blewitt, N., and Pooley, J.: An anatomic study of the axis of elbow movement in the coronal plane: Relevance to component alignment in elbow arthroplasty. J. Shoulder Elbow Surg. 3:151, 1994. 20. Braune, W., and Flugel, A.: Uber pronation and supination des menschlichen vorderarms und der hand. Arch. Anat. Physiol. 169-196, 1882. 21. Buchanan, T. S., and Shreeve, D. A.: An evaluation of optimization techniques for the prediction of muscle activation patterns during isometric tasks. J. Biomech. Eng. 118:565, 1996. 22. Capener, N.: The hand in surgery. J. Bone Joint Surg. [Br.] 38:128, 1956. 23. Cohen, M. S., and Hastings, H. Jr.: Rotatory instability of the elbow. The anatomy and role of the lateral stabilizers. J. Bone Joint Surg. [Am.] 79:225, 1997. 24. Currier, D. P.: Maximal isometric tension of the elbow extensors at varied positions. Part II. assessment of extensor components by quantitative electromyography. Phys. Ther. 52:1265, 1972. 25. Davidson, P. A., Pink, M., Perry, J., and Jobe, F. W.: Functional anatomy of the flexor pronator muscle group in relation to the medial collateral ligament of the elbow. Am. J. Sports Med. 23:245, 1995.

Chapter 3 Biomechanics of the Elbow

26. Deland, J. T., Garg, A., and Walker, P. S.: Biomechanical basis for elbow hinge-distractor design. Clin. Orthop. 215:303, 1987. 27. Dempster, W. T.: Space Requirements of the Seated Operator: Geometrical, Kinematic and Mechanical Aspects of the Body with Special Reference to the Limb. Wright Air Development Center, Project No. 7214, Wright-Patterson AFB, Ohio, 1955. 28. Dempster, W. T., and Finerty, J. C.: Relative activity of wristmoving muscles in static support of the wrist joint: An electromyographic study. Am. J. Physiol. 150:596, 1947. 29. De Sousa, O. M., De Moraes, J. L., and Viera, F. L.: Electromyographic study of the brachioradialis muscle. Anat. Rec. 139:125, 1961. 30. Dwight, T.: The movements of the ulna in rotation of the forearm. J. Anat. Physiol. 19:186, 1884. 31. Eckstein, F., Lohe, F., Muller-Gerbl, M., Steinlechner, M., and Putz, R.: Stress distribution in the trochlear notch. A model of bicentric load transmission through joints. J. Bone Joint Surg. [Br.] 76:647, 1994. 32. Ewald, F. C.: Total elbow replacement. Orthop. Clin. North Am. 6:685, 1975. 33. Fidelus, K.: The significance of the stabilizing function in the process of controlling the muscle groups of upper extremities. In Cerquiglin, S., Venerando, A., and Wartenweiler, J. (eds): Medicine and Sports, Vol. 8, Biomechanics III. Basel, Karger, 1973, p. 129. 34. Fischer, G.: Cited by Fick, R.: Handbuch der anatomie und mechanik du gelenke, unter berucksichtigung der bewegenden muskeln. Jena 2:299, 1911. 35. Funk, D. A., An, K. N., Morrey, B. F., and Daube, J. R.: Electromyographic analysis of muscles across the elbow joint. J. Orthop. Res. 5:529, 1987. 36. Fuss, F. K.: The ulnar collateral ligament of the human elbow joint. Anatomy, function and biomechanics. J. Anat. 175:203, 1991. 37. Goel, V. K., Singh, D., and Bijlani, V.: Contact areas in human elbow joints. J. Biomech. Eng. 104:169, 1982. 38. Gonzalez, R. V., Hutchins, E. L., Barr, R. E., and Abraham, L. D.: Development and evaluation of a musculoskeletal model of the elbow joint complex. J. Biomech. Eng. 118:32, 1996. 39. Goodfellow, J. W., and Bullough, P. G.: The pattern of aging of the articular cartilage of the elbow joint. J. Bone Joint Surg. [Br.] 49:175, 1967. 40. Guttierez, L. F.: A contribution to the study of the limiting factors of elbow flexion. Acta Anat. 56:146, 1964. 41. Halls, A. A., and Travill, A. A.: Transmission of pressures across the elbow joint. Anat. Rec. 150:243, 1964. 42. Hamilton, C. D., Glousman, R. E., Jobe, F. W., Brault, J., Pink, M., and Perry, J.: Dynamic stability of the elbow: Electromyographic analyses of the flexor pronator group and the extensor group in pitchers with valgus instability. J. Shoulder Elbow Surg. 5:347, 1996. 43. Heiberg, J.: The movement of the ulna in rotation of the forearm. J. Anat. Physiol. 19:237, 1884. 44. Hildebrand, K. A., Patterson, S. D., Regan, W. D., MacDermid, J. C., and King, G. J.: Functional outcome of semiconstrained total elbow arthroplasty. J. Bone Joint Surg. [Am.] 82:1379, 2000.

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45. Hollister, A. M., Gellman, H., and Waters, R. L.: The relationship of the interosseous membrane to the axis of rotation of the forearm. Clin. Orthop. 298:272, 1994. 46. Hotchkiss, R. N., An, K. N., Sowa, D. T., Basta, S., and Weiland, A. J.: An anatomic and mechanical study of the interosseous membrane of the forearm: Pathomechanics of proximal migration of the radius. J. Hand Surg. [Am.] 14:256, 1989. 47. Hotchkiss, R. N., and Weiland, A. J.: Valgus stability of the elbow. J. Orthop. Res. 5:372, 1987. 48. Hughes, R. E., Schneeberger, A. G., An, K. N., Morrey, B. F., and O’Driscoll, S. W.: Reduction of triceps muscle force after shortening of the distal humerus: A computational model. J. Shoulder Elbow Surg. 6:444, 1997. 49. Hui, F. C., Chao, E. Y., and An, K. N.: Muscle and joint forces at the elbow during isometric lifting. Orthop. Trans. 2:169, 1978. Abstract. 50. Hultkrantz, J. W.: Das ellbogengeleck and seine mechanik. Jena Fisher 1897. 51. Ishizuki, M.: Functional anatomy of the elbow joint and three-dimensional quantitative motion analysis of the elbow joint. J. Jpn. Orthop. Assoc. 53:989, 1979. 52. Kapandji, I. A.: The Physiology of the Joint: The Elbow, Flexion and Extension, 2nd ed, Vol. 1. London, Livingstone, 1970. 53. Keats, T. E., Tuslink, R., Diamond, A. E., and Williams, J. H.: Normal axial relationship of the major joints. Radiology 87:905, 1966. 54. Larson, R. F.: Forearm positioning on maximal elbowflexor force. Phys. Ther. 49:748, 1969. 55. Le Bozec, S., Maton, B., and Cnockaert, J. C.: The synergy of elbow extensor muscles during dynamic work in man. Part I. Elbow extension. Eur. J. Appl. Physiol. 44:255, 1980. 56. London, J. T.: Kinematics of the elbow. J. Bone Joint Surg. [Am.] 63:529, 1981. 57. Markolf, K. L., Lamey, D., Yang, S., Meals, R., and Hotchkiss, R.: Radioulnar load-sharing in the forearm. A study in cadavera. J. Bone Joint Surg. [Am.] 80:879, 1998. 58. Maton, B., and Bouisset, S.: The distribution of activity among the muscles of a single group during isometric contraction. Eur. J. Appl. Physiol. 37:101, 1977. 59. McGarvey, S. R., Morrey, B. F., Askew, L. J., and An, K. N.: Reliability of isometric strength testing. Temporal factors and strength variation. Clin. Orthop. 185:301, 1984. 60. Meissner, G.: Lokomotion des ellbogengelenkes ber ubd. Fortschr. Anat. Physiol. 1856. 61. Messier, R. H., Duffy, J., Litchman, H. M., et al: The electromyogram as a measure of tension in the human biceps and triceps muscles. Int. J. Mech. Sci. 13:585, 1971. 62. Mori K.: Experimental study on rotation of the forearmfunctional anatomy of the interosseous membrane. J. Jpn. Orthop. Assoc. 59:611, 1985. 63. Morrey, B. F.: Post-traumatic contracture of the elbow. Operative treatment, including distraction arthroplasty. J. Bone Joint Surg. [Am.] 72:601, 1990. 64. Morrey, B. F.: Complex instability of the elbow. J. Bone Joint Surg. [Am.] 79:460, 1997.

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Part I Fundamentals and General Considerations

65. Morrey, B. F., and An, K. N.: Articular and ligamentous contributions to the stability of the elbow joint. Am. J. Sports Med. 11:315, 1983. 66. Morrey, B. F., and An, K. N.: Functional anatomy of the ligaments of the elbow. Clin. Orthop. 201:84, 1985. 67. Morrey, B. F., An, K. N., and Stormont, T. J.: Force transmission through the radial head. J. Bone Joint Surg. [Am.] 70:250, 1988. 68. Morrey, B. F., Askew L. J., and An, K. N.: Strength function after elbow arthroplasty. Clin. Orthop. 234:43, 1988. 69. Morrey, B. F., and Chao, E. Y.: Passive motion of the elbow joint. J. Bone Joint Surg. [Am.] 58:501, 1976. 70. Morrey, B. F., Tanaka, S., and An, K. N.: Valgus stability of the elbow. A definition of primary and secondary constraints. Clin. Orthop. 265:187, 1991. 71. Motzkin, N. E., Cahalan, T. D., Morrey, B. F., An, K. N., and Chao, E. Y.: Isometric and isokinetic endurance testing of the forearm complex. Am. J. Sports Med. 19:107, 1991. 72. Nemoto, K., Itoh, Y., Horiuchi, Y., and Sasaki, T.: Advancement of the insertion of the biceps brachii muscle: A technique for increasing elbow flexion force. J. Shoulder Elbow Surg. 5:433, 1996. 73. Nicol, A. C., Berme, N., and Paul, J. P.: A biomechanical analysis of elbow joint function. In Joint Replacement in the Upper Limb. London, Institute of Mechanical Engineers, 1977, p. 45. 74. Nobuta, S.: Pressure distribution on the elbow joint and its change according to positions. J. Jpn. Soc. Clin. Biomech. Res. 13:17, 1991. 75. O’Driscoll, S. W., An, K. N., Korinek, S., and Morrey, B. F.: Kinematics of semi-constrained total elbow arthroplasty. J. Bone Joint Surg. [Br.] 74:297, 1992. 76. O’Driscoll, S. W., Bell, D. F., and Morrey, B. F.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. [Am.] 73:440, 1991. 77. O’Driscoll, S. W., Horii, E., Morrey, B. F., and Carmichael, S.: Anatomy of the ulnar part of the lateral collateral ligament of the elbow. Clin. Anat. 5:296, 1992. 78. O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Intraarticular pressure and capacity of the elbow. Arthroscopy 6:100, 1990. 79. Olsen, B. S., Henriksen, M. G., Sojbjerg, J. O., Helmig, P., and Sneppen, O. Elbow joint instability: A kinematic model. J. Shoulder Elbow Surg. 3:143, 1994. 80. Olsen, B. S., Sojbjerg, J. O., Dalstra, M., and Sneppen, O.: Kinematics of the lateral ligamentous constraints of the elbow joint. J. Shoulder Elbow Surg. 5:333, 1996. 81. Olsen, B. S., Vaesel, M. T., Sojbjerg, J. O., Helmig, P., and Sneppen, O.: Lateral collateral ligament of the elbow joint: Anatomy and kinematics. J. Shoulder Elbow Surg. 1996;5:103-112. 82. Palmer, A. K., Glisson, R. R., and Werner, F. W.: Ulnar variance determination. J. Hand Surg. [Am.] 7:376, 1982. 83. Pauly, J. E., Rushing, J. L., and Scheving, L. E.: An electromyographic study of some muscles crossing the elbow joint. Anat. Rec. 159:47, 1967. 84. Pauwels, F.: Biomechanics of locomotor apparatus. Translated by P. Maquet and R. Furlong. Berlin, Springer-Verlag, 1980.

85. Pomianowski, S., Morrey, B. F., Neale, P. G., Park, M. J., O’Driscoll, S. W., and An, K. N.: Contribution of monoblock and bipolar radial head prostheses to valgus stability of the elbow. [see comment]. J. Bone Joint Surg. [Am.] 83:1829, 2001. 86. Pomianowski, S., O’Driscoll, S. W., Neale, P. G., Park, M. J., Morrey, B. F., and An, K. N.: The effect of forearm rotation on laxity and stability of the elbow. Clin. Biomech. 16:401, 2001. 87. Pribyl, C. R., Kester, M. A., Cook, S. D., Edmunds, J. O., and Brunet, M. E.: The effect of the radial head and prosthetic radial head replacement on resisting valgus stress at the elbow. Orthopedics 9:723, 1986. 88. Ray, R. D., Johnson, R. J., and Jameson, R. M.: Rotation of the forearm: An experimental study of pronation and supination. J. Bone Joint Surg. [Am.] 33:993, 1951. 89. Ray, P. S., Kakarlapudi, K., Rajsekhar, C., and Bhamra, M. S.: Total elbow arthroplasty as primary treatment for distal humeral fractures in elderly patients. Injury 31:687, 2000. 90. Regan, W. D., Korinek, S. L., Morrey, B. F., and An, K. N.: Biomechanical study of ligaments around the elbow joint. Clin. Orthop. 271:170, 1991. 91. Sarmiento, A., Ebramzadeh, E., Brys, D., and Tarr, R.: Angular deformities and forearm function. J. Orthop. Res. 10:121, 1992. 92. Schlein, A. P.: Semiconstrained total elbow arthroplasty. Clin. Orthop. 121:222, 1976. 93. Schwab, G. H., Bennett, J. B., Woods, G. W., and Tullos, H. S.: Biomechanics of elbow instability: The role of the medial collateral ligament. Clin. Orthop. 146:42, 1980. 94. Sojbjerg, J. O., Ovesen, J., and Gundorf, C. E.: The stability of the elbow following excision of the radial head and transection of the annular ligament. An experimental study. Arch. Orthop. Trauma Surg. 106:248, 1987. 95. Sojbjerg, J. O., Ovesen, J., and Nielsen, S.: Experimental elbow instability after transection of the medial collateral ligament. Clin. Orthop. 218:186, 1987. 96. Spinner, M., and Kaplan, E. B.: The quadrate ligament of the elbow—its relationship to the stability of the proximal radio-ulnar joint. Acta Orthop. Scand. 41:632, 1970. 97. Steindler, A.: Kinesiology of the Human Body Under Normal and Pathological Conditions. Springfield, IL, Charles C. Thomas, 1955, p. 493. 98. Stevens, A., Stijns, H., Reybrouck, T., Bonte, G., Michels, A., Rosselle, N., Roelandts, P., Krauss, E., and Verheyen, G.: A polyelectromyographical study of the arm muscles at gradual isometric loading. Electromyogr Clin Neurophysiol 1973;13:465-476. 99. Stormont, T. J., An, K. N., Morrey, B. F., and Chao, E. Y.: Elbow joint contact study: Comparison of techniques. J. Biomech. 18:329, 1985. 100. Sullivan, W. E., Mortensen, O. A., Miles, M., and Greene, L. S.: Electromyographic studies of m. biceps brachii during normal voluntary movement at the elbow. Anat. Rec. 107:243, 1950. 101. Tanaka, S., An, K. N., and Morrey, B. F.: Kinematics and laxity of ulnohumeral joint under valgus-varus stress. J. Musculoskel. Res. 2:45, 1998.

Chapter 3 Biomechanics of the Elbow

102. Travill, A. A.: Electromyographic study of the extensor apparatus of the forearm. Anat. Rec. 144:373, 1962. 103. Tyrdal, S., and Olsen, B. S.: Combined hyperextension and supination of the elbow joint induces lateral ligament lesions. An experimental study of the pathoanatomy and kinematics in elbow ligament injuries. Knee Surg. Sports Traumatol. Arthrosc. 6:36, 1998. 104. Van Glabbeek, F., Van Riet, R. P., Baumfeld, J. A., Neale, P. G., O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Detrimental effects of overstuffing or understuffing with a radial head replacement in the medial collateral-ligament deficient elbow. J. Bone Joint Surg. [Am.] 86:2629, 2004.

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105. Von Lanz, T., and Wachsmuth, W.: Praktische Anatomie. Berlin, Springer-Verlag, 1959. 106. Von Meyer, H.: Cited in Steindler, A.: Kinesiology of the Human Body Under Normal and Pathological Conditions. Springfield, IL, Charles C. Thomas, 1955, p. 490. 107. Walker, P. S.: Human Joints and Their Artificial Replacements. Springfield, IL, Charles C. Thomas, 1977. p. 182. 108. Youm, Y., Dryer, R. F., Thambyrajah, K., Flatt, A. E., and Sprague, B. L.: Biomechanical analyses of forearm pronation-supination and elbow flexion-extension. J. Biomech. 12:245, 1979.

Chapter 4 Physical Examination of the Elbow

CHAPTER

4

Physical Examination of the Elbow William D. Regan and Bernard F. Morrey

INTRODUCTION This chapter deals with the basics of a general comprehensive physical examination of the elbow. Specific and focused features of the examination are pictured with the various conditions described below.

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Conditions involving the lateral joint, that is, the radiocapitellar articulation, generally evoke pain that extends over the lateral aspect of the elbow with radiation proximally to the midhumerus or distally over the forearm. The pain may be superficial, directly over the lateral epicondyle or radial head, for example, or deep, localized poorly in the area of the proximal common extensor muscle mass supplied by the posterior interosseous nerve. For reasons that remain unclear, the posterior lateral ulnohumeral joint appears to be a “watershed” referral point for a spectrum of remote conditions. Less commonly, nonspecific symptoms poorly localized to the medial aspect of the elbow can represent ulnar nerve pathology, medial epicondylitis or arthrosis. As is well known, symptoms from cervical radiculopathy can usually be distinguished by a specific radicular distribution of pain and associated neurologic abnormality of the upper extremity. Today, a suspicion of cervical etiology is readily resolved with the magnetic resonance imaging (MRI) scan.

HISTORY Without question the value of a precise history cannot be overstated. Pain is the most common complaint. The severity of the pain and whether it is intermittent or constant, the quantity and type of analgesia used, and the association of night pain are all important characteristics. The functional compromise experienced, whether it be recreational activity or activities of daily living, should be discussed. Frequently, the patient who has lived with chronic pain, such as that accompanying rheumatoid arthritis, has learned certain accommodative activities that have assisted in lessening or eliminating pain from a conscious level. When considering intervention, it is extremely helpful to determine if the pain is getting better, getting worse, or remaining constant. Functionally, the elbow is the most important joint of the upper extremity, because it places the hand in space away from or toward the body. It provides the linkage, allowing the hand to be brought to the torso, head, or mouth. Because of this, the examiner must be aware of the interplay of shoulder and wrist function as they complement the usefulness of the elbow. However, a considerable limitation of elevation and abduction function can exist at the shoulder complex without producing an appreciable compromise in most activities of daily living. This is true because only a relatively small amount of shoulder flexion and rotation is necessary to place the hand about the head or posteriorly about the waist or hip, and scapulothoracic motion can compensate for glenohumeral motion loss. Full pronation and supination can be achieved only when both the proximal and distal radioulnar joints are normal.6,25

PHYSICAL EXAMINATION INSPECTION Considerable information can be ascertained from careful visual inspection of the elbow joint. Because much of the joint is subcutaneous, any appreciable alteration in the skeletal anatomy is usually obvious. Gross soft tissue swelling or muscle atrophy is also easily observed.

AXIAL ALIGNMENT Axial malalignment of the elbow, when compared with the opposite side, suggests prior trauma or a skeletal growth disturbance. To determine the carrying angle, the forearm and hand should be supinated and the elbow extended; the angle formed by the humerus and forearm is then determined (Fig. 4-1A). Although there is considerable variation with race, age, sex, and body weight, an average of 10 degrees for men and 13 degrees for women has been calculated as the mean carrying angle from several reports.3,4,13,14 Angular deformities, such as cubitus varus or valgus, are also easily identifiable (see Fig. 4-1B and C). The elbow moves from a valgus to varus alignment as with flexion. In a post-traumatic condition, however, abnormalities in the carrying angle cannot be accurately assessed in the presence of a significant flexion contracture (see Chapter 3). Rotational deformities following supracondylar or other fractures of the humeral shaft may be difficult to perceive.

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Part II Diagnostic Considerations

FIGURE 4-1

A, The carrying angle is a clinical measurement of the angle formed by the forearm and the humerus with the elbow extended. B and C, The normal 10- to 15-degree carrying angle can be altered by injury about the elbow, causing a varus carrying angle, or so-called gunstock deformity.

LATERAL ASPECT Fullness about the infracondylar recess just inferior to the lateral condyle of the humerus, the “soft spot,” suggests either an increase in synovial fluid, synovial tissue proliferation, or radial head pathology, such as fracture, subluxation, or dislocation (Fig. 4-2). Subtle evidence of effusion can be determined by observing fullness in this area. Thin, taut, adherent skin over the lateral epicondyle may be indicative of excessive cortisone injections in this area for refractory lateral epicondylitis (see Chapter 44). A prominence involving the lateral triangle often indicates a posteriorly dislocated radial head (Fig. 4-3; see Fig. 4-22A and B).

POSTERIOR ASPECT A prominent olecranon suggests a posterior subluxation or migration of the forearm on the ulnohumeral articulation. Occasionally, marked distortion is associated with surprisingly satisfactory function (Fig. 4-4). Rupture of the triceps tendon at its insertion should be suspected if this finding is accompanied by loss of active extension. Loss of terminal passive extension of the elbow is a

sensitive but nonspecific indicator of intra-articular pathology. Loss of active motion with full passive extension suggests either mechanical (triceps avulsion) or neurologic conditions. The prominent subcutaneous olecranon bursa is readily observed posteriorly when it is inflamed or distended (Fig. 4-5). Rheumatoid nodules frequently are found on the subcutaneous border of the ulna (see Chapter 74).

MEDIAL ASPECT On occasion the ulnar nerve may be observed to displace anteriorly during flexion with recurrent subluxation of the ulnar nerve.8 Otherwise, few landmarks are observable from the medial aspect of the joint. The prominent medial epicondyle is evident unless the patient is obese.

ASSOCIATED JOINTS AND NEURAL FUNCTION No examination of the elbow is complete without a review of the cervical spine and all other components of the upper extremity. If the elbow pain has a radicular pattern, it is important to review the patient’s cervical

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FIGURE 4-2

A normal depression in the contour of the skin in the intracondylar recess (arrowhead) (A) becomes obliterated in the presence of synovitis or effusion (B).

FIGURE 4-3

Developmental posterior dislocation of the radial head (A) is associated with obvious prominence (B). Typically, this problem is associated with only minimal limitation of function.

spine alignment and range of motion and perform neurologic testing of the entire upper extremity. The main nerve roots involved with elbow function are C5-7 (Fig. 4-6). There is considerable overlap in the sensory dermatomes of the upper extremity. The general distribution of sensory levels includes C5, the lateral arm; C6, the lateral forearm; C7, the middle finger; and C8 and T1, the medial forearm and arm dermatomes, respectively. Biceps function from innervation of C5-C6 is a flexor of the elbow and forearm supinator. The reflex primarily tests C5 and some C6 competency. The C6 muscle group of most interest is the mobile wad of three, consisting of the extensor carpi radialis longus and brevis and the brachioradialis muscles. These also are known as the radial wrist extensors and should be assessed for strength and reflex integrity. The reflex is primarily a C6 function, with some C5 component. The primary elbow muscle innervated by C7 is the triceps, which should always be assessed for strength and reflex. Wrist flexion and finger extension also are primarily supplied by C7, with some C8 innervation (see Fig. 4-6). Elbow pain may be referred from the shoulder; therefore, a visual inspection of the shoulder for muscle wasting and appearance should be made, followed by an appropriate functional assessment. Specific attention should be directed toward motion and the spectrum of impingement tendinitis or rotator cuff pathology which often is manifested by pain in the brachium.

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FIGURE 4-4

Gross deformity of the elbow from a malunion of a condylar fracture. The excellent function is typical of condylar but not T-Y type malunions.

FIGURE 4-5

An inflamed or enlarged olecranon bursa is one of the more dramatic diagnoses made by observation in the region of the elbow. (From Polley, H. G., and Hunder, G. G.: Rheumatologic Interviewing and Physical Examination of the Joints, 2nd ed. Philadelphia, W.B. Saunders Co., 1978.)

For normal forearm rotation, there must be a normal anatomic relationship between the proximal and distal radioulnar joint. Inflammatory changes involving either the elbow or the wrist or both will cause a loss of forearm rotation. Disruption of the normal relationship

of the distal radioulnar joint will cause dorsal prominence of the distal ulna exaggerated by pronation and is lessened by supination. Because pronation is the common resting position of the hand, dorsal subluxation of the ulna at the wrist is often identifiable by inspection.

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C5 C6

Posterior view

A C7

FIGURE 4-6

The biceps, brachioradialis, and triceps reflexes allow evaluation of the C5, C6, and C7 nerve roots, respectively.

PALPATION OSSEOUS LANDMARKS Inspection and palpation of the medial and lateral epicondyles and the tip of the olecranon form an equilateral triangle when the elbow is flexed (Fig. 4-7). Fracture, malunion, unreduced dislocation, or growth disturbances involving the distal end of the humerus can be assessed clinically in this fashion. FIGURE 4-7

LATERAL ASPECT The lateral supracondylar region, which we call the lateral column, is readily palpable and is a valuable landmark during lateral surgical exposures (Fig. 4-8) (see Chapters 7 and 32). The definition of the location of the extensor carpi radialis brevis is carefully sought and is enhanced by radial wrist and elbow extension. Examination of the radial head is easily performed provided a joint effusion is not present. Digital pressure over the peripheral articular surface of the radial head, when combined with pronation and supination of the forearm in varying degrees of elbow flexion, will offer valuable information about this bony structure and the status of the synovium. If painful, this examination should be performed gently. Radial head or capitellar fracture thus may be suspected even when the radiographic results are negative. An effusion of the elbow is most easily identified by palpation over the lateral border

With the elbow flexed to 90 degrees, the medial and lateral epicondyles and tip of the olecranon form an equilateral triangle when viewed from posterior. When the elbow is extended, this relationship is changed to a straight line connecting these three bony landmarks (A). The relationship is altered with displaced, intra-articular distal humeral fractures (B).

of the radial head or about the posterior recess located just between the radial head and the lateral border of the olecranon (Fig. 4-9). A radio/humeral plica is appreciated by palpating the snapping of the plica with flexion and extension. As with other joints, significant effusions of hemarthrosis will limit extremes of motion, especially extension. If tense, the elbow will assume a position of maximum joint capacity, which is 80 degrees.19 Palpation of the arcade of Froshe, located approximately 2 cm anterior and 3 cm distal to the lateral epicondyle, locates the posterior interosseous nerve.

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MEDIAL ASPECT Because of the tight ligament and capsule present on the medial side of the olecranon, great difficulty is encountered in assessment of the soft tissues in this area. Palpation of the cubital tunnel is easily performed to assess

the status of the ulnar nerve (Fig. 4-10). A subluxing nerve is identified with flexion and extension. Entrapment is assessed by performing a Tinel test proximal to, at, or distal to the cubital tunnel. The flexor-pronator muscles consist of four muscles taking origin from the medial epicondyle. Wrist flexion and pronation against resistance often accentuate the pain and is consistent with a diagnosis of medial epicondylitis. The medial collateral ligament is the elbow’s primary stabilizer to valgus strain. It takes its origin slightly anterior and inferior to the medial epicondyle and fans out to attach along the greater sigmoid fossa of the ulna with both an anterior and a posterior thickening.24 With the elbow in 30 to 60 degrees of flexion, it should be palpated for tenderness along its course. Valgus stress is painful if the ligament is injured.

Ulnar nerve

Medial epicondyle

FIGURE 4-8

The lateral supracondylar interval is an avascular area that can be readily palpated and serves as an important landmark in many surgical exposures to the elbow. (From Hoppenfeld, S.: Physical Examination of the Spine and Extremities. New York, Appleton-CenturyCrofts, 1976.)

Olecranon

FIGURE 4-10

Palpation of the cubital tunnel. The ulnar nerve is identified proximal and distal to the medial epicondyle.

FIGURE 4-9

The radial head may be readily palpated. The contour and integrity of the structure may be further appreciated by pronating and supinating the forearm during this examination.

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POSTERIOR ASPECT The olecranon bursa overlies the triceps aponeurosis, which inserts on the olecranon. This area should be palpated for thickening and pain. On occasion, a spur or bony prominence may be readily palpable at the tip of the olecranon (see Chapter 84). With elbow flexion, the olecranon fossa may be identified in a thin person by careful palpation. A tense effusion is likewise detectable from this aspect. The posteromedial olecranon and ulnohumeral joint should be carefully palpated. This is a common site for olecranon spur formation and is painful with forced extension. To accentuate this pain, the elbow is snapped into full extension. The subcutaneous border of the olecranon and proximal ulna also are readily appreciated by palpation.

Biceps m.

Lacertus fibrosus (Bicipital aponeurosis)

Medial epicondyle

ANTERIOR ASPECT The cubital fossa is bordered laterally by the brachioradialis and medially by the pronator teres muscles. There are four significant structures passing through the cubital fossa from lateral to medial, including (1) the musculocutaneous nerve, (2) the biceps tendon, (3) the brachial artery, and (4) the median nerve. The musculocutaneous nerve supplying lateral forearm sensation is located deep to the brachioradialis between it and the biceps tendon and is not readily palpable. The biceps tendon is readily palpable with resisted forearm supination. The tendon should be assessed for tenderness and for continuity distally. A medial expansion, the lacertus fibrosus, is noted, which covers the common flexor muscle group as well as the brachial artery and median nerve and may be the source of compression of the median nerve. The pulse of the brachial artery is easily located, lying deep to the lacertus fibrosus (Fig. 4-11).

MOTION Perhaps no portion of the physical examination is more important than the assessment of motion. Loss of full extension is the first motion altered by most pathology. As a matter of fact, in a trauma situation, the likelihood of significant joint pathology in the face of normal elbow motion is so small as not to require radiographic analysis!15 Normally, the arc of flexion-extension, although variable, ranges from about 0 to 140 degrees plus or minus 10 degrees (Fig. 4-12).1,7,26 This range exceeds that which is normally required for activities of daily living.17 Pronation-supination may vary to a greater extent than the arc of flexion-extension. Acceptable norms of

FIGURE 4-11

The lacertus fibrosus is easily palpable at its medial margin, and this covers the brachial artery, median nerve, and becomes attenuated with the distal biceps tendon disruption.

pronation and supination are 75 and 85 degrees, respectively (Fig. 4-13). In assessing motion, the examiner should record both active and passive values. The humerus is placed in a vertical position when evaluating the arc of forearm rotation. Patients will tend to accommodate for loss of pronation by abducting the shoulder. Any significant difference between active and passive ranges of motion suggests pain or motor function as the cause. In patients with a flexion or extension contracture, the examiner should concentrate on solid or soft end points, pain or crepitus during the arc and at the end points. The examiner should then make a careful assessment of any compromised motion at the shoulder or wrist. Often, the disability will arise from a combination of factors, but it should be stressed that a full range of motion at the elbow is not essential for performance of the activities of daily living. The essential arc of elbow flexion-extension required for daily activities ranges from about 30 to 130 degrees.17 Because the loss of

74

Part II Diagnostic Considerations

145 130

50

50

80 85 Supination 0

30

Pronation

FIGURE 4-13

Normal pronation and supination is about 80 and 85 degrees, respectively. The functional arc of forearm rotation consists of approximately 50 degrees of pronation and 50 degrees of supination.

FIGURE 4-12

The normal flexion and extension of the elbows is from zero to approximately 145 degrees. The functional arc of flexion and extension about which most daily activities are achieved is 30 to 130 degrees.

Elbow motion 0–145º

Elbow motion

0–90º

0–145º

Fused, 90º

0–90º Fused, 90º

A

B FIGURE 4-14

Illustration of the marked functional limitation associated with an ankylosed elbow at 90 degrees. Notice the shoulder poorly compensates for the overall effect of limited flexion and extension in both the sagittal (A) and the transverse (B) planes.

extension up to a certain degree only shortens the lever arm of the upper extremity, flexion contractures of less than 45 degrees may have little practical significance, although patients sometimes are concerned about the cosmetic appearance (Fig. 4-14). To perform 90% of required daily activity, 50 degrees of pronation and supination are required (see Fig. 413).17 For most individuals, pronation is the most important function on the dominant side for eating and writing, and loss of pronation is compensated by shoulder abduction. On the other hand, a loss of supination of the nondominant side may significantly hinder per-

sonal hygiene needs, accepting objects, and opening of door handles. These tasks are poorly compensated by shoulder or wrist function.

STRENGTH Only gross estimates of strength are attainable in the clinical setting. Flexion and extension strength testing (Fig. 4-15) is conducted against resistance, with the forearm in neutral rotation and the elbow at 90 degrees of flexion. Extension strength is normally 70%

Chapter 4 Physical Examination of the Elbow

INSTABILITY

that of flexion strength2 and is best measured with the elbow at 90 degrees of flexion, and with the forearm in neutral rotation.10,22,23,27 Pronation (Fig. 4-16), supination, and grip strength are also best studied with the elbow at 90 degrees of flexion and the forearm in neutral rotation. Supination strength is normally about 15% greater than pronation strength.2 The dominant extremity is about 5% to 10% stronger than the nondominant side, and women are 50% as strong as men (see Chapter 5).2

In the absence of articular cartilage loss, the mechanical integrity of the radial and ulnar collateral ligaments is difficult to assess because of the intrinsic stability offered by the closely approximated surfaces of the olecranon and trochlea and the buttressing effect of the radial head against the capitellum. However, when articular cartilage has been destroyed, as in rheumatoid arthritis, or removed, as with radial head excision, collateral

A

B

FIGURE 4-15

Flexion strength is best assessed with the elbow flexed to 90 degrees and the forearm in neutral rotation. Flexion resistance is assessed while the examiner attempts to extend the elbow (A). To test extension strength, the examiner applies resistance to the patient’s ability to extend the elbow with the joint in approximately 90 degrees of flexion and the forearm in neutral (or pronated) position (B). (From Hoppenfeld, S.: Orthopedic Neurology. Philadelphia, J. B. Lippincott Co., 1977.)

A FIGURE 4-16

75

B

Pronation strength is evaluated with the patient comfortable and the elbow at 90 degrees of flexion. Pronation strength is usually measured by grasping the wrist or, less commonly, the hand with the forearm in neutral position or in supination-rotation (A). To test supination strength, the forearm is in neutral position or pronation (B).

76

Part II Diagnostic Considerations

ligament stability can be determined by the application of varus and valgus stresses. Medially, the fibers become taut in an ordered sequential fashion, proceeding from anterior to posterior as the elbow is flexed.22 Accordingly, a portion of the complex is always in tension throughout the arc of flexion (see Chapter 3).24 The radial collateral ligament resists varus stress throughout the arc of elbow flexion with varying contributions of the anterior capsule and articular surface in extension (see Chapter 3). The lateral collateral ligament complex consists of the radial collateral ligament (RCL) and the lateral ulnar collateral ligament (LUCL). The RCL maintains consistent patterns of tension throughout the arc of flexion.24 To properly assess collateral ligament integrity, the elbow should be flexed to about 15 degrees. This relaxes the anterior capsule and removes the olecranon from the fossa. Varus stress is best applied with the humerus in full internal rotation. Valgus instability is best measured with the arm in 10 degrees of flexion (Fig. 4-17). In recent years, we have used the fluoroscan routinely to assess all elbows in where a possible instability exists (see Fig. 4-17C).

A

B FIGURE 4-17

ROTATORY INSTABILITY The lateral collateral complex also includes a narrow but stout band of ligamentous tissue blending with the distal and posterior fibers of the capsule to insert distally on the crista supinatoris of the ulna. This is the lateral ulnar collateral ligament.20,24 Insufficiency of the lateral collateral ligament is responsible for posterolateral instability of the elbow.20 Posterolateral instability is elicited in two ways (see Chapter 44). The more sensitive is by flexing the shoulder and elbow 90 degrees, with the patient supine. The patient’s forearm is fully supinated, and the examiner grasps the wrist or forearm and slowly extends the elbow while applying valgus and supination movements and an axial compressive force (Fig. 4-18). This produces a rotatory subluxation of the ulnohumeral joint; that is, the rotation dislocates the radiohumeral joint posterolaterally by a coupled motion. As the elbow approaches extension, a posterior prominence (the dislocated radiohumeral joint) is noted with an obvious dimple in the skin proximal to the radial

C

A, Varus instability of the elbow is measured with the humerus in full internal rotation and a varus stress applied to the slightly flexed joint. B, Valgus instability is evaluated with the humerus in full external rotation while a valgus stress is applied to the slightly flexed joint. C, Examination under fluroscopy readily reveals medial ligament insufficiency.

Chapter 4 Physical Examination of the Elbow

Axial compression

77

Valgus

Supination

Subluxation

FIGURE 4-18

The pivot shift maneuver consists of extending the elbow with a valgus axial stress while the forearm is supinated and the elbow is being extended. The elbow tends to sublux toward full extension. A palpable snap or pop is felt with flexion and represents reduction.

FIGURE 4-19

Gross appearance and radiograph of a patient with the positive pivot shift maneuver. Note the dimple in the skin. (From O’Driscoll, S. W.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991.)

FIGURE 4-20

With partial flexion or sometimes simple pronation of the forearm, the elbow is reduced and the dimple is obliterated. (From O’Driscoll, S. W.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991.)

FIGURE 4-21

Using the arms to rise from a chair can replicate the instability pattern of posterolateral rotatory instability (PLRI).

78

Part II Diagnostic Considerations

FIGURE 4-22

A, The patient has done a push-up with hands in neutral and his arms wider than shoulder (valgus) and is at a terminal extension (axial load) of his unaffected elbow. He has apprehension in his affected left elbow (axial load + valgus). B, A close-up of the posterolateral dislocation.

head (Fig. 4-19). Additional flexion results in a sudden reduction as radius and ulna visibly snap into place on the humerus (Fig. 4-20). Alternatively, simply asking the patient to rise from a chair may also reproduce the symptomatology (Fig. 4-21). Finally, having the patient do a push-up places the elbow in the at-risk position (Fig. 4-22). These latter two tests are active apprehension signs.

References 1. American Academy of Orthopedic Surgeons: Joint Motion: Method of measuring and recording. Chicago, American Academy of Orthopedic Surgeons, 1965. 2. Askew, L. J., An, K. N., Morrey, B. F., and Chao E. Y.: Functional evaluation of the elbow: normal motion requirements and strength determination. Orthop. Trans. 5:304, 1981. 3. Atkinson, W. B., and Elftman, H.: The carrying angle of the human arm as a secondary symptom character. Anat. Rec. 91:49, 1945. 4. Beals, R. K.: The normal carrying angle of the elbow. Clin. Orthop. 119:194, 1976. 5. Beetham, W. P., Jr., Polley, H. F., Slocumb, C. H., and Weaver, W. F.: Physical Examination of the Joints. Philadelphia, W. B. Saunders Co., 1965. 6. Bert, J. M., Linscheid, R. L., and McElfresh, E. C.: Rotatory contracture of the forearm. J. Bone Joint Surg. 62A:1163, 1980. 7. Boone, D. C., and Azen, S. P.: Normal range of motion of joints in male subjects. J. Bone Joint Surg. 61A:756, 1979. 8. Childress, H. M.: Recurrent ulnar nerve dislocation at the elbow. Clin. Orthop. 108:168, 1975.

9. Daniels, L., Williams, M., and Worthingham, C.: Muscle Testing: Techniques of Manual Examination, 2nd ed. Philadelphia, W. B. Saunders Co., 1946. 10. Elkins, E. C., Ursula, M. L., and Khalil, G. W.: Objective recording of the strength of normal muscles. Arch. Phys. Med. Rehabil. 33:639, 1951. 11. Hoppenfeld, S.: Physical Examination of the Spine and Extremities. New York, Appleton-Century-Crofts, 1976. 12. Johansson, O.: Capsular and ligament injuries of the elbow joint. Acta Chir. Scand. Suppl. 287:1, 1962. 13. Keats, T. E., Teeslink, R., Diamond, A. E., and Williams, J. H.: Normal axial relationships of the major joints. Radiology 87:904, 1966. 14. Lanz, T., and Wachsmuth, W.: Praktische Anatomie. Berlin, ARM, Springer-Verlag, 1959. 15. Lennon, R. I., Riyat, M. S., Hilliam, R., Anathkrishnan, G., and Alderson, G.: Can a normal range of elbow movement predict a normal elbow x-ray? Emerg Med J 24:86, 2007. 16. McRae, R.: Clinical Orthopedic Examination. London, Churchill Livingstone, 1976. 17. Morrey, B. F., Askew, L. J., An, K. N., and Chao, E. Y.: A biomechanical study of normal functional elbow motion. J. Bone Joint Surg. 63A:872, 1981. 18. Morrey, B. F., and Chao, E. Y.: Passive motion of the elbow joint. A biomechanical study. J. Bone Joint Surg. 61A:63, 1979. 19. O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Intra-articular pressuring capacity of the elbow. Arthroscopy 6:100, 1990. 20. O’Driscoll, S. W., Morrey, B. F., and An, K. N.: Intra-articular pressuring capacity of the elbow. J. Bone Joint Surg. 73A:440, 1991.

Chapter 4 Physical Examination of the Elbow

21. O’Neill, O. R., Morrey, B. F., Tanaka, S., and An, K. N.: Compensatory motion in the upper extremity after elbow arthrodesis. Clin. Orthop. 281:89, 1992. 22. Provins, K. A., and Salter N.: Maximum torque exerted about the elbow joint. J. Appl. Physiol. 7:393, 1955. 23. Rasch, P. J.: Effect of position of forearm on strength of elbow flexion. Res. Q. 27:333, 1955. 24. Regan, W. D., Korinek, S. L., Morrey, B. F., and An, K. N.: Biomechanical study of ligaments about the elbow joint. Clin. Orthop. 271:170, 1991.

79

25. Schemitsch, E. H., Richards, R. R., and Kellam, J. F.: Plate fixation of fractures of both bones of the forearm. J. Bone Joint Surg. 71B:345, 1989. 26. Wagner, C.: Determination of the rotary flexibility of the elbow joint. Eur. J. Appl. Physiol. 37:47, 1977. 27. Williams, M., Stutzman, L.: Strength variation through the range of motion. Phys. Ther. Rev. 39:145, 1959. 28. Youm, Y., Dryer, R. F., Thambyrajahk, K., Flatt, A. E., and Sprague, B. L.: Biomechanical analysis of forearm pronation-supination and elbow flexion-extension. J. Biomech. 12:245, 1979.

80

Part II Diagnostic Considerations

CHAPTER

5

Functional Evaluation of the Elbow Bernard F. Morrey and Kai-Nan An

INTRODUCTION Involvement of the upper limb accounts for about 10% of all compensation paid in the United States for disabling work-related injuries.47,67 In addition, dysfunction of the upper extremity cost about 5.5 million lost work days in 1977.66 Elbow function consists of three activities: (1) allows the hand to be positioned in space, (2) provides the power to perform lifting activities, and (3) stabilizes the upper extremity linkage for power and fine work activities. The essential joint functions are motion, strength, and stability. However, ultimately, the final determinant of function and the ability to perform activities of daily living is pain.

ELBOW MOTION NORMAL MOTION Normal flexion and forearm rotation at the elbow are adequately measured clinically with the handheld goniometer. Forearm rotation is measured with the elbow at 90 degrees of flexion, often with the subject holding a linear object, such as a pencil, to make the measurement more objective.79 In spite of obvious limitations, investigators have concluded that a standard handheld goniometric examination by a skilled observer allows measurement of elbow flexion-extension and pronation-supination with a margin of error of less than 5%.35,95 In fact, the flexion-extension intraobserver reliability correlation coefficient is 0.99.78 Different trained observers also provide measurements that are statistically equivalent.30,78 Normal passive elbow flexion ranges between 0 and 140 to 150 degrees.1,11,44,79 Greater variation of normal forearm rotation has been described but averages about 75 degrees pronation and 85 degrees supination.1,11,44,91

INVESTIGATIVE TECHNIQUES OF MEASURING COMPLEX ACTIVE MOTION To measure the three-dimensional joint motion in daily activities, any one of several rather sophisticated experimental techniques can be used.1,95 For experimental studies, the triaxial electrogoniometer2,16,63 can simultaneously measure three-dimensional motion of more than one joint system with a high degree of reproducibility and reliability58,71 (Fig. 5-1). Video telemetry, computer-simulated motion, and electromagnetic sensors have also been developed to study three-dimensional kinematic measurement.2,71,87 Most recently, robotic techniques and miniature accelerometers and gyroscopes have been adopted to study complex upper extremity compensatory motion.49,56 For the elbow, the complex inter-relationship of shoulder and wrist function, both motion and motor activity, remains a complex and poorly understood area of investigation.32

FUNCTIONAL MOTION For most activities, the full potential of elbow motion is not needed or used. Loss of terminal flexion is more disabling than is the same degree of loss of terminal extension.14,70 Using the electrogoniometer just described, a study of 15 activities of daily living established that most functions can be performed using an arc of 100 degrees of flexion between 30 and 130 degrees (Fig. 5-2) and 100 degrees of forearm rotation equally divided between pronation and supination (Fig. 5-3). This has become the accepted standard for functional elbow motion. The motion requirements of the elbow joint needed for daily activities are really a measurement of the reaching ability of the hand. The extent to which this function is impaired by loss of elbow flexion or extension can be estimated analytically (Fig. 5-4). When motion is limited from 30 to 130 degrees, the potential area reached by the hand is reduced by about 20%. Thus, the range of elbow flexion between 30 and 130 degrees corresponds with about 80% of the normal reach capacity of the forearm and hand in a selected plane of shoulder motion. The functional impact of further loss of the flexion arc is also not equally distributed between flexion and extension. Our clinical experience indicates that flexion is of more value than extension in a ratio of about 2 : 1. Hence, a 10-degree further loss of flexion (120 degrees) is roughly equivalent to 20 degrees further loss of extension (Fig. 5-5). The optimal position of elbow fusion to accomplish activities of daily living has been accepted as 90 degrees.86 To further assess this issue, we hypothesized that the optimal position would be associated with a minimal amount of compensatory shoulder motion.71 It was surprising to observe that for discrete and fixed positions

FIGURE 5-1

The elbow electrogoniometer may be used to measure activities of daily living. A, Elbow flexion and forearm rotation to reach the back of the head. B, The subject is sitting at the activities table. (From Morrey, B. F., Askew, L. J., and Chao, E. Y.: A biomechanical study of normal functional elbow motion. J. Bone Joint Surg. 63A:872, 1981.)

140

Elbow flexion, degrees

120

100

80

60

40

FIGURE 5-2

20

0 Door

Pitcher Shoe

Chair

Sacrum

Newspaper

Waist

Knife

Head vertex Chest

Activities of daily living

Fork

Glass

Telephone

Neck Head occiput

Normal elbow flexion positions for activities of hygiene and those requiring arcs of motion are demonstrated. Most functions can be performed between 30 and 130 degrees of elbow flexion.

Part II Diagnostic Considerations

80 60 40

Pronation

20 Degrees

82

Supination

0 20 40 60 80 Glass

Fork

Sacrum

Chair Head vertex

Door Neck

Pitcher Chest

Waist

Knife

TeleNewsphone paper Head Shoe occiput

Activities of daily living

FIGURE 5-3

Routine daily activities requiring pronation and supination or arcs of motion are performed between 50 degrees pronation and 50 degrees supination.

A FIGURE 5-4

B

The reaching area of the hand in the sagittal (A) and transverse (B) planes, with simultaneous movement of the elbow and shoulder. If the elbow is held at approximately 90 degrees of flexion, marked reduction of reach potential occurs. Note also that the circumduction motion of the shoulder does not compensate for the hinged type motion of the elbow joint.

Chapter 5 Functional Evaluation of the Elbow

145° 130°

145° 130°

145° 130° 120°

110° 40°

70° 100° 0°

70°

50°

30°

0°

Functional arc

30°

0°

Optimum 70° arc

83

30° Optimum 40° arc

FIGURE 5-5

The further loss of motion from the ideal 30 to 130 degree arc is better tolerated as extension loss than as flexion loss.

the optimum position or “least worse” for most activities.

STRENGTH To understand the value and limitations of clinical strength assessment, it will be helpful to briefly review the physiology of muscle contraction and major factors affecting strength.15

z

TYPES OF MUSCLE CONTRACTION

y

x

FIGURE 5-6

As the fixed position of elbow fusion increases toward 90 degrees, activities of daily living are accomplished with the humerus less elevated and more laterally circumducted.

of the elbow, increasing the amount of shoulder motion did not provide greater use or increased function. It was also noted that for greater degrees of fixed elbow flexion, efforts to perform daily functions were accompanied by a tendency of the humerus to assume a less elevated and more lateral circumduction position (Fig. 5-6). This is consistent with the mechanical functions of these two joints; a ball-and-socket joint providing rotatory motion does not provide compensatory motion for hinge-type motion that occurs only in a single plane. This investigation did confirm the accepted tenant that 90 degrees is

There are several types of muscle contraction classified according to changes in length, force, and velocity of contraction (Fig. 5-7).5,31,60 If there is no change in muscle length during a contraction, it is called isometric. When the external force exceeds the internal force of a shortened muscle and the muscle lengthens while maintaining tension, the contraction is called an eccentric, or lengthening, contraction. In contrast, if the muscle shortens while maintaining tension, a concentric contraction occurs. For elbow flexion, eccentric force exceeds isometric force by about 20%, and isometric force exceeds concentric force by about 20% (Fig. 5-8).23,85 However, it is known that eccentric exercise is associated with muscle fiber damage. This may lead to alterations in muscle receptors that can alter joint position sense.13

FORCE CONSIDERATIONS If the muscle produces a constant internal force that exceeds the external force of the resistance, the muscle shortens, and the contraction is further characterized as isotonic. Energy use in this case is larger than that required to produce tension, which will balance the load, and the extra energy is used to shorten the muscle. If the speed of rotation of an exercising limb is predetermined and held constant, changes occur in the amount of tension developed in the muscles causing the motion. This is called an isokinetic contraction. This may

Part II Diagnostic Considerations

84

FIGURE 5-7

Isometric

Concentric

Eccentric

Constant Load

Velocity

Isotonic

Isokinetic

60

be of either the concentric or eccentric type defined earlier.

50

Speed of Contraction

40 Force (pounds)

Types of muscle contractions classified according to change in muscle length. An isometric contraction results in no change of muscle length with a constant load and velocity. The concentric contraction is defined as a shortening of the muscle, whereas the eccentric contraction occurs with lengthening of the muscle. These latter two contractions may be subclassified according to whether a constant load (isotonic) or a constant velocity (isokinetic) condition is met.

30

20

*

*

*

10

*

Flexors Extensors Starting angle

Eccentric Isometric Concentric

*

0 50

60

70

80

90 100 110 120 130 140

Elbow angle (degrees)

FIGURE 5-8

A rapidly contracting muscle generates less force than one contracting more slowly. In an isometric contraction, the velocity is zero because the resistance exceeds the ability of the muscle to move the joint. In sports, rates of motion exceeding 300 degrees per second are common. One recent study has shown that isometric training at maximum strength is more effective to increase power production than no load training at maximum velocity.88

Comparison of isometric, concentric, and eccentric flexion and extension contraction strength for different positions of elbow flexion. Note that approximately 20% greater strength may be generated with an eccentric than with an isometric contraction; the isometric contraction, on the other hand, is approximately 20% greater than the concentric type of contraction. (Modified from Singh, M.: Isotonic and isometric forces of forearm flexors and extensors. J. Appl. Physiol. 21:1436, 1966.)

FACTORS AFFECTING MAXIMUM MUSCLE TENSION Muscle Length at Contraction The relationship of muscle tension to muscle length is recognized by most clinicians and is presented graphically in the form of a length tension curve of an isolated muscle (Fig. 5-9).27 Recent studies suggest this concept is applicable to muscle systems at different anatomic sites.89 The exact nature of the relationship varies from muscle to muscle and from joint to joint, depending on the specific function. For example, a study in our laboratory demonstrated the relationship of triceps strength as a function of muscle shortening. A somewhat linear relationship with 1-, 2-, and 3-cm length change associated with 17%, 40%, and 63% strength reduction, respectively39 (Fig.

Chapter 5 Functional Evaluation of the Elbow

5-10). The length of elbow rotators change considerably over the full range of motion. The percent change at the wrist is 8; at the elbow, 55; and at the shoulder, 200.74

TECHNIQUE OF STRENGTH MEASUREMENT

Total tension

Passive tension

FIGURE 5-9

100

Developed tension Contractile tension only

(Minimum)

In the clinic, the most common study is that of static or isometric flexion-extension strength using a simple tensiometer, or spring device (Fig. 5-11).17,52 For more accurate documentation or for investigative purposes, more sophisticated devices such as a strain gauge tensiometer25 and dynamometer21,64,76 also have been used. Isokinetic strength is a more specific measurement of dynamic elbow flexion-extension function and is used more frequently today, especially for the assessment of athletic or occupational injuries. In an isokinetic muscular movement, the speed of rotation of the limb is held constant despite changes in the amount of tension developed. This isokinetic movement can be measured by means of an accommodating resistance dynamometer. Because of the accommodating load cell, the

Length

(Maximum)

An idealized length tension curve during isometric contraction demonstrates the maximal force for active muscle contractility. A greater amount of force may be attained if the muscle is stretched to some optimal point. Excessive stretching, although theoretically increasing the muscle force, in fact reduces the strength of contraction owing to loss of the ability of the contractile elements to function optimally.

Strength % normal

Tension

Rest length

When evaluating strength, either the torque created about the joint or the force generated in the hand and forearm in resisting joint rotation is measured. Either static or dynamic measuring devices may be used.

85

Elbow @ 30°

80 60 40 20 0 0

10

20

30

Shortening: origin-insertion/mm

FIGURE 5-10

Effect of the change in triceps length on extension strength.

FIGURE 5-11

A simple spring tensiometer, which is used in the clinical setting to estimate elbow flexion strength.

86

Part II Diagnostic Considerations

velocity of an exercising limb cannot be increased.60,72 As more force is exerted against the lever arm of the dynamometer, more resistance is encountered by the limb, and rotation occurs only at the predetermined constant speed. These devices accurately measure peak torque, the joint angle position at peak torque, the range of motion, and endurance.6 This technique is becoming increasingly useful for the measurement of elbow strength and endurance, and for more accurate study of the role of fatigue in arriving at disability estimates.84 This has proven particularly useful in assessing patients with biceps tendon reattachment.

about 5% for women and 10% for men.25 Strengths at the neutral forearm position were slightly greater than those at the supinated and pronated positions.25,43,76,80 For elbow extension, the average maximum torque strength is about 4 kg-m for men and 2 kg-m for women (Fig. 5-12).4 Observations for 14 female and 10 male subjects showed a gradual increase in strength as the elbow was extended and the 90 degree position generates the greatest isometric extension force.20,28,53,76 In general, the dominant extremity is about 5% to 10% stronger than the nondominant side, and men are about twice as strong as women in most positions (see Fig. 512). The isometric force of the flexors is about 40 percent greater than the isometric force of the extensors.4,45

ELBOW STRENGTH The greatest supination strength is generated from the pronated position; the converse relationship is also true.17,55 In the majority of shoulder elbow positions, the average torque of supination exceeded that of pronation by about 15 to 20 degrees for males and females. This was particularly marked when the elbow was extended. On the average, isometric pronation and supination strengths for men are 80 kg-cm and 90 kg-cm, respectively, and for women are 35 kg-cm and 55 kg-cm, respectively. The dominant and nondominant strength difference in these two types of function averaged about 10% (see Fig. 5-12). In one study,83 it was found that isometric elbow strengths of rheumatoid arthritis patients decreased in proportion to an increase in the severity of x-ray findings. The flexion and supination strengths after total elbow replacement were about two times greater than before operation.

Supination and Pronation

STATIC MEASUREMENTS Although the general tends are relatively consistent,9 absolute strength measurements are not exactly comparable owing to variations in study technique and even greater differences between individual subjects, especially correlated to body size and age.10,41 On the average, the maximum isometric torque created at the elbow joint is about 7 kg-m for men and 3.5 kg-m for women.4 Isometric muscle power is greatest during flexion at joint positions between 90 and 110 degrees.25,93 At elbow angles of 45 and 135 degrees, only about 75 percent of the maximum elbow flexion strength is generated.43,45,94 Maximum flexion strength is generated in forearm supination; forearm pronation is associated with the weakest flexion strength.18,43 Most of the torque occurs from contributions of the biceps, brachialis, and brachioradialis.28 The mean difference in isometric flexion force among the three forearm positions at various flexion angles is Flexion Extension

DYNAMIC FUNCTION Fatigue is an important consideration in altered function because routine activities require repetitive

125

1000

Torque kg - cm

800 600

100 75

400

50

200

25

0

0 M

F Flex

FIGURE 5-12

Torque kg - cm

Dominant side Nondominant side M = Males, n = 50 F = Females, n = 54

M

F Ext

M

F Pro

M

F Sup

M

F Grip

Mayo Clinic Biomechanics Laboratory study of normal elbow strength. Notice that men are approximately twice as strong as women and that a 5% to 10% difference is noted between the dominant and nondominant extremities.

Chapter 5 Functional Evaluation of the Elbow

actions, some of which may exceed one million cycles per year.22 The relative value of static and dynamic testing modalities is a debated issue. Motzkin and colleagues65 studied the relationship between isometric and isokinetic fatigue and found no consistent relationship. One reason for this is the marked variation even in test-retest studies of the same function.33 The one reliable association is that the eccentric contracture provides the greatest torque strength for both isometric and isokinetic testing modes.33,65 The relationship between strength and speed of movement is undefined.4 Many investigations support the hypothesis that maximum strength and the rate of movement are independent of each other.68,73 In a recent study,29 isokinetic peak torque and work were greater at the slower speed, as opposed to power, which was significantly greater at the faster speed.

ADDITIONAL VARIABLES OF STRENGTH ASSESSMENT In addition to the factors discussed, other confounding variables to strength testing include motivation, the learning effect of repetitive tests,51,59,81 the psychological benefit derived from repetitive testing,37,54 and the influence of the time of day,58 age, and even body size.10,41 The motivation factor is a variable that is well recognized but is difficult to control, quantitate, or eliminate.19,50,85 The rate of attaining maximum strength during repetitive exertion has been suggested as a possible objective criterion for judging whether a subject is voluntarily exerting full muscular strength or is not giving an honest effort.50 The eccentric : concentric strength ratios as well as the difference between these ratios at the high and the low speeds were highly effective in distinguishing maximal from submaximal efforts,24 and we do currently use this information clinically to assess for “functional” behavior.

STABILITY By virtue of the inherent stability afforded by the joint articulation, clinical instability of the elbow may be a perplexing problem (see Chapters 28 through 30). Ligamentous injury most commonly occurs in association with radial head fracture42,82 or elbow dislocation. Recurrent dislocations, however, occur in only 1% to 2% of patients.54 In fact, recurrent instability at the elbow is most commonly a rotatory instability due to insufficiency of the lateral ulnar collateral ligament69 and is discussed at length in Chapter 48. The clinical concept of complex instability is becoming more recognized. The “unhappy triad” refers specifically to fractures of the

87

radial head and coronoid in association with collateral ligament injury. Quantification of instability is difficult; studies are being conducted to understand instability, but no well-defined standard exists to clinically grade this parameter (see Chapter 4).8

FUNCTIONAL EVALUATION OF THE ELBOW PERFORMANCE INDICES An objective and reproducible means of evaluating the elbow by considering all of these features of function is obviously desirable. A tradeoff exists between a complex but detailed assessment protocol and one that is simple but not sufficiently thorough. A complete and comprehensive assessment that might be useful in a research facility is not practical clinically. For a clinician, a meaningful rating system should be both complete and readily amenable to an office practice (Table 5-1). A single parameter or index composed of all pertinent variables should accurately reflect the gradation of objective function, as discussed earlier. To be of further value, the rating system should include consideration of the presence of pain and specific daily functions that serve as surrogates to several functional variables as they apply to a discrete activity. Finally, it is also realized that no index or system is capable of discriminating changes in function of the full spectrum of pathology. A tool to describe the state of an athlete with tennis elbow is not adequate to describe the dysfunction of rheumatoid arthritis. To date, most proposed rating systems consider both objective function and subjective features (motion, strength, stability, pain, and the ability to perform daily activities).77 Most systems have been developed to document the effectiveness of surgical intervention (Table 5-2).26,40,75 TABLE 5-1 Characteristics and Implications of Patient Assessment Tools Trait

Implication

Short

High compliance

Reflects reality

Valid to draw conclusions

Easy

Nonambiguous questions

Reliable

• Accurate for all respondents • Effective in person or by communiqué

Universal

Addresses broad spectrum of conditions

Validated Variation

Believable data

Reliable

Make decisions

Accurate

Based on outcome

88

Part II Diagnostic Considerations

Functional Assessment and Rating Schemes for the Elbow

TABLE 5-2 Reference

Inglis and Pellicci40 26

Ewald et al.

Pain

Motion

Strength

Stability

ADL

Deformity

Total

30

28

10

—

20

12 (contracture)

100

50

10

—

—

30

5 (contracture)

100

5 (varus/valgus) 75

50

25

25

—

—

—

13a

20

10

—

10

10

10

50

Broberg and Morrey12

40

25

10

10

15

—

100

JOA40a

30

30

—

10

20

10

100

45

20

—

10

25

—

100

Prichard

Brumfield

62

Morrey (MEPS)

100

ADL, activity of daily living; JOA, Japanese Orthopaedic Association; MEPS, Mayo Elbow Performance Score.

TABLE 5-3 Function

Mayo Elbow Performance Score Points

Definition (Points)

Pain

45

None (45) Mild (30) Moderate (15) Severe (0)

Motion

20

Arc >100 degrees (20) Arc 50-100 degrees (15) Arc 90; good, 75-89; fair, 60-74; poor, 65 years); 120 mg (≤ 65 years)

Comparable to 10 mg morphine; reduce dose in patients weighing > Intensity b. Isometric exercises initially c. Control elbow position and loads 5. Integration into the Kinetic-Kinematic Chain a. Elbow rehabilitation = total body rehabilitation b. Treat kinetic-kinematic chain deficits c. Evaluate equipment, training, and movement skills

may successfully rehabilitate a wide variety of elbow disorders while minimizing complications.

References 1. Adams, R., and Morrey, B.: The effect of cryocompression on the elbow: a prospective randomized study. AAOS Annual Meeting. Anaheim, CA, Feb 1999. 2. Akeson, W., Amiel, D., and Woo, S.: Immobility effects on synovial joints. The pathomechanics of joint contracture. Biorheology 17:95, 1980. 3. Allen, R.: Physical agents used in the management of chronic pain by physical therapists. Phys. Med. Rehabil. Clin. North Am. 17:315, 2006. 4. Amiel, D., Akeson, W., Harwood, F., and Frank, C. B.: Stress deprivation effect on metabolic turnover of the medial collateral ligament collage–a comparison between 9 and 12 week immobilization. Clin. Orthop. Rel. Res. 172:265, 1983. 5. An, K., Hui, F., Morrey, B., Linscheid, R. L., and Chao, E. Y.: Muscles across the elbow joint: A biomechanical analysis. J. Biomech. 14:659, 1981. 6. An, K.-N., and Morrey, B.: Biomechanics of the elbow. In Morrey, B. (ed.): The Elbow and Its Disorders, 3rd ed. Philadelphia, W. B. Saunders Co., 2000, p. 43. 7. Bassett, F., Kirkpatrick, J., Engelhardt, D., et al. Cryotherapy induced nerve injury. Am. J. Sports Med. 20:516, 1992. 8. Bisset, L., Paungmali, A., Vicenzino, B., and Beller, E.: A systematic review and meta-analysis of clinical trials on physical interventions for lateral epicondylalgia. Br. J. Sports Med. 39:411, 2005.

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9. Blackmore. S.: Splinting for elbow injuries and contractures. Atlas Hand Clin. 2001:21-50 10. Bleakley, D., and McDonough, S.: The use of ice in the treatment of acute soft tissue injury: a systematic review of randomized controlled trials. Am. J. Sports Med. 32:251, 2004. 11. Buchbinder, R., Green, S., Youd, J., Assendelft, W. J. J., Barnsley, L., and Smidt, N.: Shock waves for lateral elbow pain. The Cochrane Library 4:1, 2006. 12. Butler, D.: Mobilization of the nervouse system. Melbourne, Australia, Churchill Livingstone, 1991. 13. Chinchalker, S., and Szekeres, M.: Rehabilitation of elbow trauma. Hand Clin. 20:363, 2004. 14. Davidson, P., Pink, M., Perry, J., and Jobe, F. W.: Functional anatomy of the flexor pronator muscle group in relation to the medial collateral ligament of the elbow. Am. J. Sports Med. 23:245, 1995. 15. Dunning, C., Zarzour, Z. D., Patterson, S. D., Johnson, J. A., and King, G. J.: Muscle forces and pronation stabilize the lateral ligament deficient elbow. Clin. Orthop. Rel. Res. 338:118, 2001. 16. Elliot, B., Fleisig, G., and Escamilla, R.: Technique effects on upper limb loading in the tennis serve. J. Sci. Med. Sport 6:76, 2003. 17. Fleisig, G., Barrentine, S., Escamilla, R., and Andrews, J. R.: Biomechanics of overhand throwing with implications for injuries. Sports Med 1996;21:421-437. 18. Flowers, K., and LaStayo, P.: Effect of total end range time on improving passive range of motion. J. Hand Ther. 7:150, 1994. 19. Green, D., and McCoy, H.: Turnbuckle orthotic correction of elbow-flexion contractures after acute injuries. J. Bone Joint Surg. 61A:1092, 1979. 20. Green, S., Buchbinder, R., Barnsley, L., Nall, S., White, M., Smidt, N., and Assendelft, W. J. Non-steroidal antiinflammatory drugs (NSAIDS) for treating lateral elbow pain in adults. Cochrane Database Systematic Review 2, 2002. 21. Halar, E., and Bell, K.: Immobility. In DeLisa, J., and Gans, B. (eds.): Rehabilitation Medicine: Principles and Practice. Philadelphia, Lippincott-Raven, 1998, p. 1015. 22. Hardy, M., and Woodal, W.: Therapeutic effects of heat, cold, and stretch on connective tissue. J. Hand Ther. 11:148, 1998. 23. Hatch, G., Pink, M., Mohr, K., Sethi, P. M., and Jobe, F. W.: The effect of tennis racket grip size on forearm muscle firing patterns. Am. J. Sports Med. 34:1977, 2006. 24. Keizer, S., Rutten, H., Pilot, P., Moore, N. N., Vos, J. J., and Verburg, A. D. Botulinum toxin injection versus surgical treatment for tennis elbow. Clin. Orthop. Rel. Res. (401):125, 2002. 25. Kibler, W., and Sciasica, A.: Kinetic chain contributions to elbow function and dysfunction in sports. Clin. Sports Med. 23:545, 2004. 26. Lee, M., LaStayo, P., and vonKersburg, A.: A supination splint worn distal to the elbow. J. Hand Ther. 16:190, 2003. 27. Lewis, M., Hay, E., Paterson, S., and Croft, P. Local steroid injections for tennis elbow: does the pain get worse before it gets better? Clin. J. Sports Med. 21:330, 2005.

28. Magermans, D., Chadwick, E., Veeger, H., and van der Helm, F. C.: Requirements for upper extremity motions during activities of daily living. Clin. Biomech. 20:591, 2005. 29. Manias, P., and Stasinopoulos, D.: A controlled clinical pilot trial to study the effectiveness of ice as a supplement to the exercise programme fo rhte management of lateral elbow tendinopathy. Br. J. Sports Med. 40:81, 2006. 30. Mehallo, C., Drezner, J., and Bytomski, J.: Practical management: nonsteroidal antiinflammatory drug (NSAID) use in athletic injuries. Clin. J. Sports Med. 16:170, 2006. 31. Mishra, A., and Pavelko, T.: Treatment of chronic elbow tendinosis with buffered platelet rich plasma. Am. J. Sports Med. 34:1174, 2006. 32. Morrey, B.: The posttraumatic stiff elbow. Clin. Orthop. Rel. Res. 431:26, 2005. 33. Morrey, B., and An, K.-N.: Stability of the elbow: osseous constraints. J. Shoulder Elbow Surg. 14:174S, 2005. 34. Morrey, B., An, K., and Stormont, T.: Force transmission through the radial head. J. Bone Joint Surg. 70A:250, 1988. 35. Morrey, B., Askew, L., and Chao, E. Y.: A biomechanical study of normal functional elbow motion. J. Bone Joint Surg. 63A:872, 1981. 36. Murray, I., and Johnson, G.: A study of the external forces and moments at the shoulder and elbow while performing every day tasks. Clin. Biomech. 19:586, 2004. 37. Nirschl, R.: Prevention and treatment of elbow and shoulder injuries in the tennis player. Clin. Sports Med. 7:289, 1988. 38. Nirschl, R., Rodin, D., Ochiai, D., Maartmann-Moe, C., and DEX-AHE-01-99 Study Group: Iontophoretic administration of dexamethasone sodium phosphate for acute lateral epicondylitis. Am. J. Sports Med. 31:189, 2003. 39. Nussbaum, E.: The influence of ultrasound on healing. J. Hand Ther. 11:140, 1998. 40. O’Driscoll, S.: Classification and spectrum of elbow instability: chronic instability. In Morrey, B. (ed.): The Elbow and Its Disorders. Philadelphia, W.B. Saunders Company, 1993, p. 453. 41. O’Driscoll, S., Bell, D., and Morrey, B.: Posterolateral rotary instability of the elbow. J. Bone Joint Surg. 73A:440, 1991. 42. Paoloni, J., Appleyard, R., Nelson, J., and Murrell, G. A.: Topical nitric oxide application in the treatment of chronic extensor tendinosis at the elbow. Am. J. Sports Med. 31:915, 2003. 43. Park, M., and Ahmad, C.: Dynamic contributions of the flexor-pronator mass to elbow valgus stability. J. Bone Joint Surg. 86A:2268, 2004. 44. Smidt, N., Assendelft, W., Arola, H., Malmiuaara, A., Green, S., Buchbinder, R., van der Windt, D. A., and Bouter, L. M.: Effectiveness of physiotherapy for lateral epicondylitis: a systematic review. Ann. Intern. Med. 35:51, 2003. 45. Smidt, N., Assendelft, W., and van der Windt, D.: Corticosteroid injections for lateral epicondylitis: a systematic review. Pain 96:23, 2002. 46. Taylor, D., Dalton, J., Seaber, A., and Garrett, W. E. Jr.: Viscoelastic properties of muscle-tendon units: the biome-

Chapter 9 Principles of Elbow Rehabilitation

chanical effects of stretching. Am. J. Sports Med. 18:300, 1990. 47. Trudel, D., Duley, J., Zastrow, I., Kerr, E. W., Davidson, R., and MacDermid, J. C.: Rehabilitation for patients with lateral epicondylitis: a systematic review. J. Hand Ther. 17:243, 2004. 48. Warden, S., Avin, K., Beck, E., DeWolf, M. E., Hagemeier, M. A., and Martin, K. M.: Low-intensity pulsed ultrasound accelerates and a non-steroidal anti-inflammatory drug delays knee ligament healing. Am. J. Sports Med. 34:1094, 2006.

159

49. Warren, C., Lehman, J., and Koblanski, J.: Heat and stretch procedures: an evaluation using rat tail tendon. Arch. Phys. Med. Rehabil. 57:122, 1976. 50. Wilk, K., Reinold, M., and Andrews, J.: Rehabilitation of the thrower’s elbow. Clin. Sports Med. 23:765, 2004. 51. Dhert, W. J., O’Driscoll, S., van Royen, B., and Salter, R. B.: Effects of immoblization and continuous passive motion on post-operative muscle atrophy in mature rabbits. Can. J. Surg. 31:185, 1988. 52. Wyke, B.: The neurology of joints. Ann. R. Coll. Surg. Engl. 41:25, 1966.

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CHAPTER

10

Continuous Passive Motion Shawn W. O’Driscoll

INTRODUCTION In 1960, Salter and Field16 showed that immobilization of a rabbit knee joint under continuous compression, provided by either a compression device or forced position, resulted in pressure necrosis of cartilage. In 1965, Salter and colleagues17 reported the deleterious effects of immobilization on the articular cartilage of rabbit knee joints and the resultant lesion that they termed obliterative degeneration of articular cartilage. Salter15 believed that, “The relative place of rest and of motion is considerably less controversial on the basis of experimental investigation than on the basis of clinical empiricism.” He reasoned that because immobilization is obviously unhealthy for joints, and if intermittent movement is healthier for both normal and injured joints, then perhaps continuous motion would be even better. Because of the fatigability of skeletal muscle, and because a patient could not be expected to move his or her own joint constantly, he concluded that for motion to be continuous, it would also have to be passive. Thus, he invented the concept of continuous passive motion, which has come to be known as simply CPM. Salter also believed that CPM would have an added advantage; namely, that if the movement was reasonably slow, it should be possible to apply it immediately after injury or operation without causing the patient undue pain.

FOUR STAGES OF ELBOW STIFFNESS Because the elbow is so prone to post-traumatic and postsurgical stiffness, CPM should be especially useful in maintaining motion and preventing such stiffness. The rationale for this is much clearer if one understands the stages of stiffness, of which there are four. The first stage, occurring within minutes to hours following surgery or trauma, is caused by bleeding. The second stage, which occurs during the next few hours and days is very similar but progresses more slowly. It is due to edema. Both bleeding and edema result in swell-

ing of the periarticular tissues, thereby diminishing their compliance. The immediate effect is to limit joint motion and make it more painful and, therefore, less acceptable to the patient. Thus, stiffness in these first two stages is avoided by preventing swelling. This can be accomplished by ensuring that the joint is moved through its entire range of motion right from the start, rather than only a portion of its range. CPM is required for this purpose. The third stage is characterized by deposition of extracellular matrix and the formation of granulation tissue commencing near the end of the first week. It continues for days or weeks. The stiffness is still soft but may require the use of splints to regain motion. The fourth stage commencing after about a month results from fibrosis and is often amenable only to splinting or surgical treatment.

PRINCIPLES OF USE Based on an understanding of how stiffness develops, the principles of use of CPM are readily understandable. Until motion is started, it is preferable to elevate the limb with the elbow in full extension and wrapped in a Jones dressing to minimize swelling. It should not be a compressive wrap because of the risk of losing circulation. A drain is usually useful to prevent accumulation of blood. Before starting CPM, all circumferential wrapping (e.g., Jones, cling) should be removed and replaced with a single elastic sleeve. Failure to do this may cause soft tissue injuries due to shear stresses. Once CPM is started, it is optimal that the full potential range of motion of that specific joint be used (Fig. 10-1A and B). Essentially, the tissues are being squeezed alternately in flexion and extension. CPM causes a sinusoidal oscillation in hydraulic pressure within and around the joint.2,9 This not only rids them of excess blood and fluid but prevents further edema from accumulating.8 In the first 24 hours, swelling can develop in minutes (due to bleeding), so CPM should be virtually continuous. This has a beneficial effect on healing soft tissues similar to that seen with compressive therapy after eccentric muscle injury.6 Bathroom privileges are allowed, and the patient is instructed to come out of the CPM device once every hour for 5 minutes. This safety precaution is to reduce the risk of a pressure or stretch related nerve palsy. As the number of days following surgery increases, the amount of time required for swelling to develop increases also, so that longer periods out of the machine are permitted. CPM requires close supervision by someone skilled with its use, so it is mandatory that the patient and family are involved and educated from the beginning regarding the principles of use and how to monitor the

Chapter 10 Continuous Passive Motion

161

limb. Frequent checking and slight adjustments of position prevent pressure-related problems. The arm tends to slip out of the machine, so it must frequently be pulled back into it. Nurses do not always have sufficient time, or sometimes the experience, to look after these needs. The patients and their families develop a keen sense of responsibility very quickly and become an invaluable asset. A preoperative instructional video is useful to educate them and should be watched again postoperatively. The CPM should be used long enough to get the patient through the period during which he or she will be unable to accomplish the full range of motion by himself or herself. This can be several days to a month. For most contracture releases, it tends to be used for four weeks.

PAIN CONTROL Such use of CPM immediately raises questions and concerns regarding uncontrollable pain. Pain control in these patients requires that we depart from traditional teaching. Rather than adjusting the motion according to the level of pain, the analgesia is adjusted instead. This is no different from the principles of anesthesia for surgery. Some patients have more pain than others, and appropriate modifications need to be made for them. We favor the use of an indwelling catheter for continuous brachial plexus block anesthesia (see Fig. 10-1C).13-17 This permits a range from analgesia to anesthesia by varying the dose of bupivacaine, a long-acting local anesthetic. The initial bolus dose may be sufficient to cause a complete or near-complete motor and sensory block. Motor blockade requires splinting of the wrist to protect it. Moderate or complete anesthesia, as opposed to analgesia with minimal anesthesia, requires careful attention to the status of the limb overall, because the patient’s protective pain response is no longer present. Insidious development of a nerve palsy during CPM may be less likely to go unnoticed if some motor and sensory function are still present in each nerve during CPM. The catheter is left in place for 3 days in hospital, then removed. At that time, the patient is usually able to maintain the same range of motion with either no or only oral analgesics. The goal is to have the patient leave the hospital capable of moving the elbow from about 10 to 140 degrees of motion actively. Of course, full motion is preferred. A patient-controlled analgesia pump with morphine has also been used effectively if a brachial plexus block is contraindicated, unsuccessful, or not available.

FIGURE 10-1

A to C, The range of motion on continuous passive motion should be full. This permits the tissues to be squeezed alternately in flexion and extension. Analgesia is accomplished with an indwelling catheter for continuous brachial plexus block anesthesia using bupivacaine, a long-acting local anesthetic.

ADVANTAGES There are a number of advantages to the use of CPM. Most surgeons are aware from the total knee experience that analgesic consumption is diminished because the patients are more comfortable (although

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Part III Surgery and Rehabilitation

not always during the first day or two). Swelling is diminished. Although most experience with CPM has been in the knees, several studies have documented the efficacy of CPM for the elbow.1,5,11,12 In two separate studies, postoperative CPM was found to improve elbow motion following open reduction internal fixation (ORIF) of distal humeral fractures in children and adolescents.11,12 CPM has been also documented to be effective in assisting with restoration of elbow motion after surgical release1 or resection of heterotopic ossification.5 My personal experience using CPM in strict accordance with the principles just outlined has convinced me that motion is obtained faster and more completely than that obtained without the use of CPM, despite the studies that failed to show such a benefit in the knee (Fig. 10-2A and B).7,8,18,19 This can be explained on the basis of how CPM has been routinely used. Typical protocols involve starting with a small range of motion tolerated by the patient, for example 30 degrees, and gradually increasing the range each day. This pattern of use is not in compliance with the essential principles of CPM. What such a protocol does is to increase swelling and bleeding due to constant tissue irritation. The most astonishing benefit of CPM, however, is how rapidly the patient is capable of pain-free and relatively full function and, therefore, return to work and sport.

COMPLICATIONS In using CPM for the elbow, I have become aware of the protocol for complications. Bleeding is increased but rarely sufficiently to require a transfusion, although

FIGURE 10-2

some patients have been taken back to the operating room for evacuation of a hematoma under such circumstances. Those elbows were treated by being placed back into a well-padded Jones dressing with an anterior plaster slab holding the elbow in extension, then elevating the arm for 2 to 4 days. It is clear to me that in certain settings, CPM can increase the risk of soft tissue and wound healing complications. Hematomas and seromas, as just mentioned, are more likely if CPM is used after having raised a skin flap as part of the exposure. When large skin flaps have been raised and the extent of deep dissection has been extensive, CPM may cause shearing of the soft tissues that is not able to be tolerated. This leads to dark discoloration of the skin, possibly full thickness necrosis, blistering and/or persistent weeping through the wound. If the wound is not closed very securely (subcuticular stitches are insufficient), it may dehisce. I have changed my use of skin incisions and CPM in these types of cases for these reasons. In such circumstances I prefer medial/lateral incisions with no skin flaps rather than a posterior incision. If I am concerned about soft tissues, I delay the use of CPM for 2 to 4 days until I see how the tissues respond to the surgery itself. Despite these concerns, no patients have lost a flap, although a few have had areas of necrosis that healed by secondary intention without further surgery. One patient almost fell out of bed from lying so close to the edge while using the machine. A word of caution is required. No circumferential wrapping (e.g., cling) should be left on the elbow once the CPM is started. A single elastic tube grip sleeve is best. I do not generally use CPM in the presence of ligament injuries or potential joint instability because it is not possible to keep the elbow perfectly aligned

Typical range of motion seen 3 weeks postoperatively (A) and 1 year postoperatively (B) following a distraction interposition arthroplasty treated postoperatively using continuous passive motion.

Chapter 10 Continuous Passive Motion

with the axis of rotation of the machine. Malalignment would stress the ligaments and bony stabilizers of the joint. Neurologic complications of CPM are well recognized for the leg. With the elbow, CPM can permit pressureinduced palsies, which can be prevented as discussed earlier. Delayed-onset ulnar neuropathy is a risk after contracture release. It appears to be due to compression by the cubital tunnel retinaculum and can largely be prevented by prophylactic nerve decompression. Obviously, any nerve can develop a palsy from stretch as well.

INDICATIONS AND CONTRAINDICATIONS CPM is indicated to prevent stiffness and to retain motion obtained at the time of surgery, particularly following contracture release, synovectomy, and excision of heterotopic ossification. I do not generally use it following the replacement of arthritic joints that were stiff preoperatively because of concern about soft tissue complications that would be serious overlying a prosthesis. It is relatively contraindicated if the soft tissue constraints (ligaments) are insufficient, if fixation of fractures has not been rigid, or if the elbow is unstable.

HOME USE I believe that the use of CPM at home is as important as, or perhaps even more than, its use in the hospital. The home rental market for CPM machines is being served by at least two domestic companies at the time of this writing, so home use of CPM is practical. The typical requirement is in the range of 4 weeks for an elbow that has been stiff before surgery, and 1 to 2 weeks for elbows requiring assistance to prevent stiffness from developing.

References 1. Aldridge, J. M. 3rd, Atkins, T. A., Gunneson, E. E., and Urbaniak, J. R.: Anterior release of the elbow for extension loss. J. Bone Joint Surg. Am. 86A:1955, 2004. 2. Breen, T. F., Gelberman R. H., and Ackerman, G. N.: Elbow flexion contractures: Treatment by anterior release and continuous passive motion. J. Hand Surg. Br. 13-B:286, 1988. 3. Brown, A. R., Weiss, R., Greenberg, C., Flatow, E. L., and Bigliani, L. U.: Interscalene block for shoulder arthroscopy: comparison with general anesthesia. Arthroscopy. 9:295, 1993.

163

4. Gaumann, D. M., Lennon, R. L., and Wedel, D. J.: Continuous axillary block for postoperative pain management. Reg. Anesth. 13:77, 1988. 5. Ippolito, E., Formisano, R., Caterini, R., Farsetti, P., and Penta, F.: Resection of elbow ossification and continous passive motion in postcomatose patients. J. Hand Surg. Am. 24:546-553, 1999. 6. Kraemer, W. J., Bush, J. A., Wickham, R. B., Denegar, C. R., Gomez, A. L., Gotshalk, L. A., Duncan N. D., Volek, J. S., Putukian, M., and Sebastianelli, W. J.: Influence of compression therapy on symptoms following soft tissue injury from maximal eccentric exercise. J. Orthop. Sports Phys. Ther. 31:282, 2001. 7. O’Driscoll, S. W., and Giori, N. J.: Continuous passive motion (CPM): Theory and principles of clinical application. J. Rehabil. Res. Dev. 37:179, 2000. 8. O’Driscoll, S. W., Kumar, A., and Salter, R. B.: The effect of continuous passive motion on the clearance of a hemarthrosis from a synovial joint: an experimental investigation in the rabbit. Clin. Orthop. 176:305, 1983. 9. O’Driscoll, S. W., Kumar, A., and Salter, R. B.: The effect of the volume of effusion, joint position and continuous passive motion on intra-articular pressure in the rabbit knee. J. Rheumatol. 10:360, 1983. 10. Pope, R. O., Corcoran, S., McCaul, K., and Howie, D. W.: Continuous passive motion after primary total knee arthroplasty. J. Bone Joint Surg. Br. 79:914, 1997. 11. Remia, L. F., Richards, K., and Waters, P. M.: The BryanMorrey triceps-sparing approach to open reduction of Tcondylohumeral fractures in adolescents: Cybex evaluation of triceps function and elbow motion. J. Pediatr. Orthop. 24:615, 2004. 12. Re, P. R., Waters, P. M., and Hreski, T.: T-condylar fractures of the distal humerus in children and adolescents. J. Pediatr. Orthop. 19:313, 1999. 13. Rice, A. S. C.: Prevention of nerve damage in brachial plexus block. XVI Annual European Society of Regional Anaesthesia Congress. London, 1997. 14. Romness, D. W., and Rand, J. A.: The role of continuous passive motion following total knee arthroplasty. Clin. Orthop. 226:34, 1988. 15. Salter, R. B.: Motion vs. rest. Why immobilize joints? J. Bone Joint Surg. 64-B:251, 1982. 16. Salter, R. B., and Field, P.: The effects of continuous compression on living articular cartilage. An experimental investigation. J. Bone Joint Surg. 42-A:31, 1960. 17. Salter, R. B., McNeill, O. R., and Carbin, R.: The pathological changes in articular cartilage associated with persistent joint deformity. An experimental investigation. Studies of the rheumatoid diseases. Third Canadian Conference on Research in Rheumatic Diseases. Toronto, 1965, p. 33. 18. Schroeder, L. E., Horlocker, T. T., and Schroeder, D. R.: The efficacy of axillary block for surgical procedures about the elbow. Anesth. Analg. 83:747, 1996. 19. Stinson, L. J., Lennon, R., Adams, R., and Morrey, B.: The technique and efficacy of axillary catheter analgesia as an adjunct to distraction elbow arthroplasty: a prospective study. J. Shoulder Elbow Surg. 2:182, 1993.

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11

Splints and Bracing at the Elbow

common problem in the orthopedic practice. Unfortunately, in the author’s experience the use of aggressive physical therapy to address post-traumatic stiffness is not always successful and, in fact, as often as not, makes the contracture worse. This justifies the use of splinting in this clinical setting, but to understand the rationale of splinting for this condition, it is necessary to understand the physiology of the process.

Bernard F. Morrey

PATHOLOGY OF ELBOW CONTRACTURE INTRODUCTION Elbow splints are frequently employed at the elbow and function in several capacities: protection both static and dynamic, to deliver flexion or extension torque. Specifically, the four types of braces or splints used in the postoperative and postinjury management of the elbow include resting and hinged splints, and dynamic and static adjustable splints.10

STATIC AND PROTECTIVE SPLINTS Prophylactic bracing is occasionally employed at the elbow, typically to avoid excessive extension in the athlete.9 Further static splinting for the elbow is commonly used for short periods as a protective measure after injury or surgery. Previously used commonly in those with rheumatoid arthritis, largely because of the effectiveness of disease remitting agents, this type of splinting is uncommonly indicated today (Fig. 11-1). For the unstable elbow a hinged splint is used (Fig. 11-2). By initially locking the hinge, the same device can be used as a resting static splint; some designs allow conversion to a movable stabilizing device. Hinged splints allow active motion and are employed primarily for ligament healing. Occasionally, a hinged brace is prescribed for the resected elbow, but compliance is variable, and I rarely use this type of device.

ELBOW STIFFNESS The most common complication of elbow injury, and even in some arthritic conditions, is stiffness. The most important means of avoiding this after a fracture is rigid fixation accompanied by early motion of the joint (see Chapter 22). After fracture dislocation, it has been demonstrated that immobilization lasting for more than 4 weeks resulted in less satisfactory outcome in each patient,2 and despite the recognized value of early motion after injury or surgery stiffness of the elbow remains a

The exact reason that the elbow is so prone to joint contracture is not known with certainty. What is recognized is that the elbow is one of the most congruous joints in the body (see Chapter 2). Normally, the capsule is translucent, but with insult, it undergoes a marked hypertrophy and extensive cross-linking of the fibrils, as demonstrated on scanning electron microscopy (Fig. 11-3). In some instances, a severe elbow contracture has been observed after trivial insult or such as “strain” without fracture or dislocation. Under these circumstances, the elbow may contract rapidly, often within 2 to 3 weeks. An explanation of the rapid development of elbow contracture may be provided by the basic investigations on wound contracture. Experimental data demonstrate that dermal wounds undergo approximately 80% of the anticipated contracture within the first 3 weeks1 (Fig. 11-4). Continuous motion, if properly used, has been shown to be an important adjunct to successfully alter this tendency and hence prevent contracture (see Chapter 10). After trauma, this modality is used with confidence, particularly if rigid fixation has been afforded to the fracture and if pain and inflammation can be controlled. After 3 to 8 weeks of treatment and if the fracture has been rigidly fixed and it is thought that force can safely be applied, the use of splints may be introduced in order to gain further motion. In general, the author’s philosophy is that continuous motion machine maintains motion but does not gain motion. The use of static adjustable splints attains motion both in flexion and in extension. The question then arises as to the best method of providing a force to stretch the periarticular soft tissues. There are four possibilities: physical therapy, continuous passive motion, dynamic splinting, and static adjustable splinting.

MANAGEMENT OF ELBOW STIFFNESS PHYSICAL THERAPY Physical therapy must be executed with extreme caution in the post-traumatic or inflamed elbow. The reason for

Chapter 11 Splints and Bracing at the Elbow

FIGURE 11-1

165

Resting splint rarely used for more than 2

to 3 weeks. FIGURE 11-3

Scanning electron microscopy (×30) showing dense hypertrophy of collagen fibrils with extensive cross-linkage sites.

50

FIGURE 11-2

Hinged splint allows static support when the mechanism is locked, and active motion thereafter as desired.

this is that passive stretch, in and of itself, can introduce the very inflammation that one is trying to treat in the course of the therapy. Inflammation results in contracture and thus is an obstacle to the treatment goal. A well-trained experienced physical therapist who understands this principle can be of value, especially to assist in addressing concurrent shoulder and wrist stiffness. Such expertise is not possible in the author’s practice; therefore, I have never prescribed physical therapy for a patient of mine with elbow stiffness.

Area cm2

40

30

20

10

0 0

10

20

30

40

50

60

Days

FIGURE 11-4

Experimental data showing that the majority of tissue contracture occurs in the first 3 weeks. (With permission from Billingham, R. E., and Russell, P. S.: Studies on wound healing, with special reference to the phenomenon of contracture in experimental wounds in rabbits’ skin. Ann. Surg. 144:961, 1956, p. 964.)

RESTORATIVE SPLINTING Restorative splinting can be used to assist in attaining elbow motion. Splints are designed according to two diverse philosophies: dynamic or static-adjustable. To comprehend the rationale of dynamic or static adjustable splinting, some understanding of the soft tissue about the elbow as viscoelastic tissue is necessary. If the

soft tissue at the elbow can be considered viscoelastic tissue, its response to a constant versus a variable force is different.12 The theoretical response to a constant force is shown in Figure 11-5. This load results in soft tissue deformation, which is called creep.8 However, what is

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Tissue elongation

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Constant force

Time

FIGURE 11-5

Viscoelastic tissue response to a constant force resulting in gradual stretching of the tissue. The potential for inflammation, however, is not demonstrated by this curve but is possible if the force is constantly present, which is the case in dynamic loading.

FIGURE 11-6

Commercially available dynamic splint. The tension and excursion may be adjusted by the patient.

Applied discrete force

not demonstrated in this illustration is the development of inflammation as a biologic response to this constant load. Inflammation can alter this idealized curve, and in the author’s opinion, inflammation is a common byproduct of dynamic splinting. Nonetheless, this remains an attractive option for many11 (Fig. 11-6). The alternate approach to the stiff elbow is the use of static adjustable splints. In this modality, a constant force is applied to the elbow that results in strain being imparted to the tissue. However, the force is not continuously applied, allowing stress relaxation to occur within the soft tissue sleeve over a period of time. This type of treatment has been employed extensively at the knee by serial casting and has also been effectively used at the elbow.14 It is believed that the stress-free relaxation lessens the likelihood of inflammation, and thus, the elbow in our practice and opinion is more amenable to this type of load application (Fig. 11-7). The constant force is applied so as to exceed the elastic limits of the tissue or result in a stretch. But if this load is maintained at a constant and is not further increased, tissue relaxation should occur over time. Finally, to further avoid the likelihood of inflammation, the patient controls the amount and duration of tension being applied. This is done within a very discrete set of recommendations and a very defined program (see Appendix). However, as with all torque generated across the elbow by whatever means, a compressive force is also applied to the system. This joint force can reach considerable proportions and is a function of the direction of the torque and the ankle of the elbow at the time of application13 (Fig. 11-8). Ideally, the splint hinge mechanism absorbs the majority of the force which is primarily compressive in nature whether the application is in flexion or extension.

Constant length

Time

FIGURE 11-7

The tissue response to the application of a single discrete force results in stress relaxation of the viscoelastic tissue.

DYNAMIC SPLINTING Dynamic splinting has been a popular means of treating impending or developing stiffness. The concept has been used in hemophiliacs by employing a system of reverse dynamic slings at both the knee and at the elbow.3 The earliest examples of dynamic splinting employed rubber

Chapter 11 Splints and Bracing at the Elbow

bands to deliver to torque. At the elbow, this has given way to much more sophisticated mechanics and devices. Data has been published to suggest the value of dynamic splinting to assist extension after triceps injury.7 Today, there are several readily available commercial devices that employ this concept (see Fig. 11-6). The splint is well tolerated at least initially but can cause pain and introduce reactive inflammation if used too aggressively.

STATIC ADJUSTABLE SPLINTS The classic static adjustable splint is a turnbuckle type and use was reintroduced several years ago by Green and associates.6 He reported an 80% success rate in treating elbow contractures from various etiologies, especially those with a major flexion contracture. Two problems were identified with the use of these splints.

Force, normalized

1

167

As the contracture decreases to less than 30 degrees, the effectiveness of a turnbuckle to develop an extension torque decreases. Applying an extension load at this angle results in the majority of the force distributed so as to separate the hinge, and less than 25% of the force actually exerts an extension torque on the elbow (Fig. 11-9). The ability of this concept to enhance post-traumatic elbow motion has been recently demonstrated in a clinical trial.4 In another study, 11 of 22 patients gained satisfactory motion after initiating turnbuckle type bracing in a sample of those who no longer were benefiting from physical therapy.5 Hence, to develop a more effective device, a means was developed to apply the force through a gear mechanism at the axis of flexion; by so doing the entire force is then applied as intended: either to extend or to flex. (Fig. 11-10). The brace was designed at our institution and is termed the “Mayo Elbow Brace (Don Joy,

Rotation

.8

.2 Compression

0

40

80

120

160 160 180

120

80

40

0

Flexion angle, degrees

FIGURE 11-8

During flexion and extension variable proportions of the applied load is converted to rotatory or compressive forces at the joints.

FIGURE 11-10 A static adjustable splint currently used by the author in which the extension torque is directly applied at the axis of rotation. Note use of air pads to distribute the local pressure exerted on the skin.

FIGURE 11-9

Sine 45° = 0.70

45°

Force = 70% extension 30% separation

A

15°

B

30°

Sine 15° = 0.25 Force = 25% extension 75% separation

A, With the elbow at 90 degrees, the anteriorly placed turnbuckle provides an effective force, approximately 70% of which is directed at extending the elbow and 30% in separating the joint itself. B, When the elbow is at 30 degrees, the turnbuckle is working through an angle of 15 degrees. The sine function of 15 degrees is .25. This means that 75% of the force is going to separate the hinge and distract the two components of the brace, and only 25% of the force is actually extending the elbow. These types of braces become inefficient as the elbow gets closer toward full extension.

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FIGURE 11-11 The same splint shown in Figure 11-10, but reversed and being used in the flexion mode; hence, the splint is called the universal splint in our practice. For flexion the straps nearest to the hinge are released to avoid impingement.

Flexion* Extension

Out#

Flexion* Extension

Out#

Flexion* Extension

Out#

Flexion* Extension

Rise

Rise 8 am Noon

1 pm Hours

6 pm Hours

Hours

10 pm Sleep

• *Either flexion or extension; circled as needed. • # Hours out of splint.

FIGURE 11-12

BOX 11-1

A sample of the daily program given to the patient at the time of splint prescription.

Basic Instructions for the Use of Static Adjustable Splints

The following general guidelines for the use of turnbuckle splints may be modified, or instructions may be given to you, depending on your individual needs and progress. I. General Goals

• To attain improved motion of your elbow, inflammation must be avoided. This is done with the use of the anti-inflammatory agents, heat and ice, and education of the patient to the signs of inflammation. II. Cardinal Signs of Inflammation

• Increased soreness, increased discomfort, swelling, or commonly a progressive loss of motion, rather than day-to-day improvement. III. Treatment of Inflammation

• Avoid the causative factor. Be less vigorous with the turnbuckle splint, adhere to the heat and ice program, and take anti-inflammatory agents as prescribed. If they are inadequate, they may need to be modified. Check with us or your local doctor. IV. Direction of Improvement

• Often, both increased elbow flexion and extension is being sought. In general, the motion that is needed most is addressed at night. The opposite motion is encouraged during the day.

V. Typical Splint Program

• On rising in the morning, the splint is removed. Gently flex and extend the elbow while taking a hot bath or shower for approximately 15 minutes. Take an antiinflammatory agent. • Apply the splint in a direction opposite to that which was used at night. Apply it to the point where it is recognized that the elbow is being stressed but pain is not present. • The splint may be removed for 1 hour in the morning, 1 hour in the afternoon, and 1 hour in the evening. Reapply the splint in the opposite direction after these rest periods. • Use the elbow when out of the splint, as able, in the evening. If the elbow is sore or seems inflamed, apply ice for 15 minutes. If the elbow is not inflamed but is stiff, apply heat for 15 minutes while gently working the joint in flexion and extension. • On going to bed at night, apply the splint in the direction needed most. Application should be sufficiently strong so you are aware that the elbow is being stressed, and a person should be able to sleep comfortably for about 6 hours without being awakened by elbow pain. After reading these instructions, contact your physician if you have any specific questions.

Chapter 11 Splints and Bracing at the Elbow

Orthopedics) and is able to hyperextend to enhance the ability to completely resolve the contracture (Fig. 11-11). However, with flexion to more than 100 or 110 degrees, the anterior soft tissue tends to bunch up, limiting further flexion. For this reason, the straps closest to the joint may be released to allow unencumbered flexion. Over the 4-year period from the introduction of this device in 2003 through 2006, we have prescribed approximately 200 braces for patients with various expressions of elbow stiffness. This experience has resulted in the application program shown in Box 11-1 and Figure 11-12. It should be noted that an adequate amount of time should be spent with the patient to explain the rationale of the brace and specific use and goals for the specific device being used.

References 1. Billingham, R. E., and Russell, P. S.: Studies on wound healing, with special reference to the phenomenon of contracture in experimental wounds in rabbits’ skin. Ann. Surg. 144:961, 1956. 2. Broberg, M. A., and Morrey, B. F.: Results of treatment of fracture dislocations of the elbow. Clin. Orthop. 216:109, 1987. 3. Dickson, R. A.: Reversed dynamic slings: A new concept in the treatment of post-traumatic elbow flexion contractures. Injury 8:35, 1976. 4. Doornberg, J. N., Ring, D., and Jupiter, J. B.: Static progressive splinting for posttraumatic elbow stiffness. J. Orthop. Trauma. 20:400, 2006.

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5. Gelinas, J. J., Faber, K. J., Patterson, S. D., and King, G. J.: The effectiveness of turnbuckle splinting for elbow contractures. J. Bone Joint Surg. 82B:74, 2000. 6. Green, D. P., and McCoy, H.: Turnbuckle orthotic correction of elbow-flexion contractures after acute injuries. J. Bone Joint Surg. 61A:1092, 1979. 7. Greer, M. A., and Miklos-Essenberg, M. E.: Early mobilization using dynamic splinting with acute triceps tendon avulsion. J. Hand Ther. 18:365, quiz 371, 2005. 8. Kottke, F. J., Pauley, D. L., and Ptak, R. A.: The rationale for prolonged stretching for correction of shortening of connective tissue. Arch. Phys. Med. Rehab. 47:345, 1966. 9. Lake, A. W, Sitler, M. R., Stearne, D. J., Swanik, C. B., and Tierney, R.: Effectiveness of prophylactic hyperextension elbow braces on limiting active and passive elbow extension prephysiological and postphysiological loading. J. Orthop. Sports Phys. Ther. 35:837, 2005. 10. Morrey, B. F.: The use of splints with the stiff elbow. In Heckman, M. D. (ed.): Prospective in Orthopedic Surgery, Vol. I, No. 1. St. Louis, Quality Medical Publishing, 1990, p. 141. 11. Richard, R., Shanesy, C. P., and Miller, S. F.: Dynamic versus static splints: A prospective case for sustained stress. J. Burn Care Rehab. 16:284, 1995. 12. Richards, R. L., and Staley, M. J.: Biophysical aspects of normal skin and burn scar. In Richard, F. L., and Staley, M. J. (eds.): Burn Care and Rehabilitation: Principles and Practice. Philadelphia, F. A. Davis, 1994, p. 65. 13. Szekeres, M.: A biomechanical analysis of static progressive elbow flexion splinting. J. Hand Ther. 19:34, 2006. 14. Zander, C. L., and Healy, N. L.: Elbow flexion contractures treated with serial casts and conservative therapy. J. Hand Surg. 17:694, 1992.

Chapter 12 Imaging of the Pediatric Elbow

CHAPTER

12

Imaging of the Pediatric Elbow Kristen B. Thomas, Alan D. Hoffman, and E. Richard Graviss

INTRODUCTION Radiography is the primary imaging modality for evaluation of the elbow in children, as it is in adults. Although the radiographic views are the same, the pediatric patient is unique. Injury is the primary reason for evaluating the immature elbow. Children’s reactions to the process of imaging vary greatly, although they are usually related to the patient’s age and the nature of the injury sustained. Modern radiographic equipment is a cornerstone for obtaining high-quality imaging studies. However, the most important component is a qualified radiologic technologist who understands the child’s anxieties and who has empathy for the child’s fears. Such a technologist is aware of patient and parent anxiety and that the minor motions of the elbow may cause pain. The assistance of an accompanying parent or guardian may be useful and, occasionally, is mandatory when there is insufficient technical help available for positioning. A gentle, friendly approach that is firm but reassuring will yield optimal radiographic examinations of the pediatric elbow. The basic elbow study consists of anteroposterior and lateral views. The lateral view invariably is obtained first, because the child maintains an injured elbow in the flexed position. The patient is seated beside a radiographic table so that the arm can be elevated parallel to the level of the table top and a 90-degree flexed position can be maintained. The forearm should be supinated gently, with the thumb pointed up, positioning all three bones of the elbow in the lateral projection. The anteroposterior view then is obtained with the forearm positioned up and the elbow extended slowly as much as the injury allows. If necessary, the anteroposterior view can be divided into two segments: one with the humerus parallel to the radiographic film, and the other with the forearm parallel to the radiographic film. This provides better anatomic detail than does a single exposure with the elbow partially flexed and neither component parallel to the film.

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Some unstable fractures and dislocations require splinting such that views obtained at right angles are usually sufficient for the initial diagnosis. The fracture or dislocation with obvious clinical deformity is usually less problematic than is the subtle fracture, which may go undetected. When the patient is examined for subtle fractures, the lateral view is extremely important, and positioning should be flawless. This view provides clues concerning the injured elbow, such as the anterior and posterior fat pad signs. It also allows for visual alignment of the distal humeral ossification segments with the shaft of the humerus and with the radius. In certain instances, a fluoroscopic examination of the elbow may yield valuable information. The examiner can manipulate the elbow to obtain the precise obliquity required to best evaluate a subtle abnormality. Instead of repeating a radiograph multiple times, optimal positioning can be obtained while watching real-time fluoroscopy and then digital fluoroscopic spot radiographs are easily taken. Tomography, using either a simple linear method or a complex motion system, can be used in the evaluation of growth plates that have closed prematurely following trauma. In most practices, computed tomography has completely replaced conventional tomography. Computed tomography examinations now take only seconds to perform, and sedation is usually not necessary, even in very young infants and children. Using current 64slice multidetector computed tomography technology (MDCT), isovoxel images can be obtained in all three planes down to 0.6-mm collimation. This allows detailed imaging, with the bony trabecular pattern well seen. Examinations are obtained with the patient in the prone position, with the affected arm held above the head with about 90 degrees of flexion at the elbow. Sagittal and coronal two-dimensional reformatted images as well as three-dimensional reconstructions are then made from the raw data. MDCT is a sensitive (92%) and specific (79%) method of evaluating for radiographically occult elbow fractures.6 MDCT can also use automated tube current modulation to markedly decrease the radiation dose to the patient compared with fixed-tube current techniques. MDCT can also be performed with no image degradation through a cast.3 MDCT with reformatting can better delineate intra-articular fractures (Fig. 12-1). Three-dimensional imaging can also provide additional information and help define the joint relationships to aid surgical planning (Figs. 12-2 and 12-3). The resulting three-dimensional image can be rotated in all planes with computerized subtraction of the adjacent soft tissues and bones, if needed. Magnetic resonance imaging (MRI) and ultrasonography are increasingly being used to evaluate the elbow. MRI can evaluate cartilage, bone marrow, and soft tissue structures (Fig. 12-4).8 Radiographs do not show bone

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FIGURE 12-1

Computed tomography two-dimensional reformatted coronal image of intra-articular distal humeral intercondylar fracture in a 13-year-old boy who was injured while skateboarding.

FIGURE 12-2

Computed tomography three-dimensional reconstruction of a complex intra-articular distal humeral fracture from the posterior view in a 14-year-old boy injured while playing basketball.

FIGURE 12-3

Magnetic resonance imaging of a 13-year-old boy with elbow pain, coronal (A) and sagittal (B) views. T1-weighted images show a defect in the capitellum. No loose body is seen. The clinical diagnosis was Panner’s disease, and symptoms resolved in a few months without specific therapy.

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FIGURE 12-5 FIGURE 12-4

Computed tomography three-dimensional reconstruction of an 11-year-old boy with the clinical diagnosis of Panner’s disease. Several small loose bodies are seen adjacent to the capitellum.

bruising, or cartilaginous or soft tissue injury and can underestimate physeal injury. MRI is also occasionally used to better define elbow fractures.2 Owing to the length of the MRI examination (at least 20 minutes), children younger than 5 years old will usually need sedation so that optimal MRI images can be obtained. In children with elbow trauma, MRI reveals a broad spectrum of bone and soft tissue injury, including ligamentous injury, beyond that recognized by radiographs. However, the additional information afforded by MRI usually does not change treatment or clinical outcome in acute elbow trauma.9 MRI can be very useful in the evaluation of osteochondritis dissecans (OCD) of the capitellum. MRI provides information about the size, location and stability of the OCD lesion. All of these factors are important when deciding treatment options (see Chapter 20 for more discussion). Unstable OCD lesions in the capitellum have a peripheral rim of high signal or an underlying fluid-filled cyst on T2-weighted images (Fig. 12-5). Stable OCD lesions have no peripheral signal abnormality.12 Loose bodies in the elbow joint can be visualized by MRI or MDCT, but smaller detached bone fragments are usually better visualized using MDCT (Fig 12-6). Ultrasonography has the ability to dynamically delineate soft tissues and cartilage in detail.13 Soft tissue swell-

Magnetic resonance imaging (T2 sagittal image) of a 12-year-old boy demonstrates osteochondritis dessicans (OCD) of the capitellum with increased signal extending to the articular surface consistent with full-thickness cartilage loss. This indicates a potentially unstable OCD bone fragment that has not yet detached. A moderate elbow joint effusion is also present.

FIGURE 12-6

Computed tomography axial image of a 12year-old female gymnast demonstrates a small intraarticular loose body within the posterior elbow joint (arrow) secondary to osteochondritis dissecans of the capitellum. The tiny bone fragment was not visible on radiographs.

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ing, a mass (including vascular masses investigated with duplex Doppler and color flow Doppler), joint effusion, and fractures, particularly in infants and young children with unossified or minimally ossified epiphyses, are studied with this modality.1,7 Ultrasound can detect early changes of medial epicondylar fragmentation and OCD of the capitellum, even in the asymptomatic stage in selected populations such as young baseball players.10 As with other portions of the appendicular and axial skeletons, side-to-side comparison may be helpful when one is presented with an unfamiliar or a rare variant. Comparison views need to be obtained only in selected cases,14,15 such as when consultation with the standard text of normal cases is not helpful.5,11,17

NORMAL DEVELOPMENT The maturation sequence at the elbow is more variable than that of the hand and wrist. Nonetheless, an appreciation of the normal sequence and timing of the appearance of ossification centers and maturation patterns is important for an understanding of the radiographic

FIGURE 12-7

appearances of the elbow in children (Fig. 12-7). Several mnemonics have been suggested to help remember the time of appearance of the ossification of these centers. We find that the cross-connecting ossification centers (see Fig. 12-7B) are particularly helpful in remembering at least the order of ossification of these centers. An atlas entitled Radiology of the Pediatric Elbow5 shows standards for elbow maturation in children. To consistently evaluate the developing elbow, one must analyze each of the secondary centers of ossification, accounting for its appearance, configuration during development, and associated changes as it matures and eventually fuses with the humeral shaft. The descriptions that follow are brief, but they outline the major points of development and maturation of the centers.

CAPITELLUM The capitellum, the first of the elbow’s six centers to ossify, generally becomes radiographically visible during the first and second years of life. Initially spherical, it flattens posteriorly to conform to the adjacent distal end of the humerus. The physis is broader posteriorly than

A, Normal left elbow showing the secondary centers: capitellum (c); medial epicondyle (m); radial head (r); trochlea (t); olecranon (o); and lateral epicondyle (l). B, The approximate age at time of appearance of these centers is indicated in years. The cross connecting the secondary centers of the distal humerus serves as a reminder of the order of ossification of these centers. (Modified from Brodeur, A. E., Silberstein, M. J., Graviss, E. R., and Luisiri, A.: The basic tenets for appropriate evaluation of the elbow in pediatrics. Curr. Probl. Diagn. Radiol. 12:1, 1983.)

Chapter 12 Imaging of the Pediatric Elbow

anteriorly, giving the capitellum the appearance of a downward tilt; however, this appearance gradually disappears during the first decade (Fig. 12-8). During maturation, the capitellum fuses with the trochlea and the lateral epicondyle before it unites with the humeral shaft (Fig. 12-9). The orientation of the capitellum with the humerus can be evaluated with a true lateral projection. The anterior surface of the humerus is gently bowed posteriorly, from the insertion of the deltoid muscle to the superior aspect of the coronoid fossa. A line drawn along the anterior surface of the humerus, from the deltoid insertion to the top of the coronoid fossa, should pass through the middle third of the capitellum. For practical reasons, most lateral examinations of the elbow do not include the deltoid insertion; therefore, one must use the most proximal portion of the humerus included on the radiograph. These two points determine the anterohumeral line, which passes precisely through the posterior half of the middle third of the capitellum. The capitellum is oriented anteriorly to the distal humerus. One also may draw a curvilinear line along the coronoid fossa. The extension of that line inferiorly should touch the anterior portion of the capitellum. These two lines permit the detection of subtle supracondylar fractures, particularly Salter-Harris type I supracondylar fractures, with minimal posterior dis-

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placement of the distal humeral epiphysis with the capitellar ossification center.

RADIOCAPITELLAR LINE The radiocapitellar line is a line drawn through the long axis of the proximal radial shaft that should, in the absence of dislocation, pass through the middle of the capitellum ossification center. This is generally true in anteroposterior, lateral, or any oblique projection. In early development, however, the radial metaphysis is wedged so that on the anteroposterior projection a normal radial shaft line may appear to extend laterally to the capitellum. However, on the lateral projection, the normal radiocapitellar line can be appreciated (Fig. 12-10). In older patients, although it may appear that the radiocapitellar line is normal in one projection in a patient with a radial head dislocation, it invariably will be abnormal in the projection taken at right angles, generally the lateral projection.18

MEDIAL EPICONDYLE The medial epicondyle is the second elbow ossification center to appear in the normal sequence, usually at about 4 years. Lying posteromedially, it is often best appreciated on the lateral projection (Fig. 12-11). Fre-

FIGURE 12-8

Lateral elbow radiograph of a 2.5-year-old girl. A line along the anterior humeral shaft normally intersects the posterior half of the middle third of the capitellum. The continuation of the curved coronoid line just touches the anterior edge of the ossified capitellum. The angle formed by the coronoid line and humeral shaft line should contain the majority of the ossified capitellum.

FIGURE 12-9

A 13-year-old girl in whom the capitellum has joined with the lateral epicondyle and trochlea before fusion with the humeral shaft. Note the normal sclerotic radial epiphysis that is wider than the radial neck.

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ossification center. In a child between 4 and 8 years of age, at the time of appearance of the medial epicondyle and the trochlear ossification centers, a radiograph suggesting a trochlear ossification center, without visualization of a medial epicondyle center, should suggest that fracture and dislocation of the medial epicondyle have in fact occurred.13

RADIAL HEAD EPIPHYSIS The initial ossification of this epiphysis is fairly predictable and usually occurs in the fifth year (see Fig. 12-7B). Although usually beginning as a sphere, the radial head epiphysis often matures as one or more flat sclerotic centers. This pattern may be mistakenly interpreted as a fracture. With maturation, the physis on the anteroposterior radiograph is wider laterally than medially, and this appearance, combined with the medial angulation of the radius at the junction of its shaft and neck, may suggest dislocation on anteroposterior views. Lateral projection of the elbow will not confirm a suspected dislocation. With further maturation of ossification of the proximal radial ossification center, the normal relationship of the radius and capitellum can be seen on anteroposterior radiographs. Notches or clefts of the metaphysis of the proximal radius often are seen as normal variations of ossification during maturation.11,17 Because fractures of the radial neck are extracapsular, they are not associated with hemarthrosis and abnormalities of the humeral fat pads.19

FIGURE 12-10

A, Normal 7-month-old girl with apparent abnormal radiocapitellar line on the anteroposterior radiograph because of wedging of the metaphysis. B, The relationship between the radial shaft and capitellum is normal on the lateral radiograph.

quently, it develops from more than one ossific nucleus. Although it is the second humeral ossification center to appear, its development is slow, and it is usually the last center to unite with the humeral shaft in the normal child, sometimes as late as 15 or 16 years of age.20 This center may fuse with the trochlea before uniting with the humeral shaft. Injuries involving the nonunited medial epicondyle are relatively common and are among the most difficult to evaluate. Consequently, to avoid errors, Rodgers suggests making a habit of identifying the presence and the position of the medial epicondyle ossification center in each case.16 A classic example of the importance of appreciating the sequence of humeral ossification center appearance is avulsion and displacement of the medial epicondyle ossification center. This frequently results in the displacement of the medial epicondyle into the normal position of the trochlear

TROCHLEAR EPIPHYSIS Ossification of the trochlea appears at about 8 years and often is initially multicentric (Figs. 12-12 and 12-13B). The trochlea frequently maintains an irregular contour during its development and should not be confused with abnormal processes such as trauma or avascular necrosis (Fig. 12-14). The trochlea will fuse with the capitellum before fusion with the distal humeral shaft. It is seldom fractured, except when associated with the vertical component of a supracondylar fracture or when its lateral edge is involved with a lateral condylar fracture.

OLECRANON The ossification center of the olecranon usually develops at 9 years of age, shortly after the trochlea and just before the lateral epicondylar epiphysis. The proximal end of the ulna flattens and becomes sclerotic just before the olecranon physis ossifies. Two ossification centers most often develop, and there is great variability in the configuration of the epiphysis. This results in an occasional misdiagnosis of acute fracture. The posterior

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179

FIGURE 12-11 A, A 10-year old boy with a normal posteromedially lying ossification center for the medial epicondyle (arrows) seen posterior to the humeral shaft on the lateral projection. B, Another 10-year-old boy who sustained trauma resulting in avulsion of the medial epicondyle, which is displaced anteriorly (arrows) on the lateral projection, and displaced medially (C), and rotated on the anteroposterior projection.

FIGURE 12-12 Multiple ossification nuclei of developing trochlea (arrow) in a 9-year-old boy.

ossification center is usually bigger than the anterior ossification center (Fig. 12-15), and these separate centers generally unite before fusion with the proximal humerus. This process usually begins at about 14 years of age. The pattern of closure of the olecranon physis is distinct, with fusion occurring first along the joint line and then extending posteriorly. Frequently, fractures are wedged in the opposite direction.21 The olecranon physis has prominent sclerotic margins just before closure. Fusion proceeds posteriorly from the joint side or the anterior surface (Fig. 12-16). During its development, the physeal line remains relatively perpendicular to the ulnar shaft. As a result of differential growth, often with maturation, the olecranon growth plate, which initially is proximal to the elbow joint, comes to lie at a midelbow joint level by the time of fusion. This “wandering physeal line of the olecranon” does not occur in all individuals.4

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Part IV Conditions Affecting the Child’s Elbow

FIGURE 12-13 A, Lateral radiograph with lucent region in the proximal radial shaft (arrows). B, Anteroposterior view shows prominent but normal radial tuberosity (arrow). Residual changes from previous transcondylar fracture of the humerus are seen.

FIGURE 12-15 FIGURE 12-14 A 9-year-old boy with beginning ossification of the lateral epicondyle (arrow) from a thin sliver widely separated from the metaphysis. Note the irregular outline of the developing ossification center of the trochlea.

Although the majority of olecranon fractures are intracapsular and are associated with alterations of fat pads, some are not. The tip of the olecranon is not within the capsule in some individuals. The only other common site of fracture related to the elbow that lies outside the joint capsule is the radial neck (see Chapter 17).4

A 13-year-old boy with double ossification center of the olecranon. The anterior nucleus is smaller.

LATERAL EPICONDYLE The ossification center of the lateral epicondyle is the last of the elbow centers to appear. Usually, this center is first seen at 10 or 11 years of age, and it fuses to the humeral shaft at about 14 years of age. Unlike the other ossification centers of the elbow, the lateral epicondyle appears first as a thin sliver rather than as a round or spherical ossific nucleus (see Fig. 12-14). Ossification commences at the lateral portion of the cartilaginous mold so that the physis appears particu-

Chapter 12 Imaging of the Pediatric Elbow

larly wide. The inferior aspect of the ossification begins at the junction between the distal humerus and the capitellum.5 Because of the relatively short time between the appearance and fusion of this center, it is not always certain in individual cases whether ossification is delayed or fusion to the humerus already has occurred. To avoid confusion about this point, it must be realized that before ossification, the humerus has a sharp, straight, sloping metaphyseal line that changes to a sloping, curving margin at the capitellum. The fused lateral epicondyle, on the other hand, has a smooth, curved margin that is continuous with the capitellum (Fig. 12-17).

FIGURE 12-16 A 14-year-old male in whom closure of the olecranon growth plate has begun anteriorly. Note the sclerotic margin of that portion of the growth plate that remains unfused.

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NORMAL VARIANTS In addition to the confusing appearances caused by the normally developing elbow, there are a few variations from normal or unusual appearances that should be noted. The radial tuberosity lies medially at the junction of the medial shaft and the neck. On lateral views, it may

FIGURE 12-18 A 6-year-old boy with perforated olecranon fossa. There has been a previous supracondylar fracture.

FIGURE 12-17 A, A 9-year-old boy in whom ossification of the lateral epicondyle is about to begin. The metaphysis has a sharp, straight, sloping margin. B, The fusing lateral epicondyle in this 14-year-old boy, in contrast, has a smoother, rounded margin.

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Part IV Conditions Affecting the Child’s Elbow

FIGURE 12-19 Supracondylar process in a mature elbow. Anteroposterior (A) and lateral (B) radiographs.

appear as an undermineralized focus and may be misinterpreted as a destructive lesion of the bone (see Fig. 12-13). On the anteroposterior view of the elbow, the thin humeral olecranon fossa occasionally appears to be entirely lucent, the so-called perforated olecranon fossa (Fig. 12-18). In some instances, there is a bridge of bone crossing or a separate ossicle within a perforated olecranon fossa. A rare anatomic anomaly is a bony projection from the anterior medial distal humerus known as the supracondylar process (Fig. 12-19), which is discussed in Chapter 2.

References 1. Barr, L. L.: Elbow. Clin. Diagn. Ultrasound 30:135, 1995. 2. Beltran, J., Rosenberg, Z. S., Kawelblum, M., Montes, L., Bergman, A. G., and Strongwater, A.: Pediatric elbow fractures: MRI evaluation. Skeletal Radiol. 23:277, 1994. 3. Blickman, J. G., Dunlop, R. W., Sanzone, C. F., and Franklin, P. D.: Is CT useful in the traumatized pediatric elbow? Pediatr. Radiol. 20:184, 1990. 4. Brodeur, A. E., Silberstein, M. J., and Graviss, E. R. Radiology of the Pediatric Elbow. Boston, G. K. Hall, 1981. 5. Brodeur, A. E., Silberstein, M. J., Graviss, E. R., and Luisiri, A.: The basic tenets for appropriate evaluation of the elbow in pediatrics. Curr. Probl. Diagn. Radiol. 12:1, 1983. 6. Chapman, V., Grottkau, B., Albright, M., Elaini, A., Halpern, E., and Jaramillo, D.: MDCT of the elbow in pediatric patients with posttraumatic elbow effusion. A. J. R. 187:812, 2006.

7. Davidson, R. S., Markowitz, R. I., Dormans, J., and Drummond, D. S.: Ultrasonographic evaluation of the elbow in infants and young children after suspected trauma. J. Bone Joint Surg. 76A:1804, 1994. 8. Gordon, A. C., Friedman, L., and White, P. G.: Pictorial review: Magnetic resonance imaging of the paediatric elbow. Clin. Radiol. 52:582, 1997. 9. Griffith, J. F., Roebuck, D. J., Cheng, J. C. Y., Chan, Y. L., Rainer, T. H., Ng, B. K., and Metreweli, C.: Acute elbow trauma in children: Spectrum of injury revealed by MR imaging not apparent on radiographs. A. J. R. 176:53, 2001. 10. Harada, M., Takahara, M., Sasaki, J., Mura, N., Ito, T., and Ogino, T.: Using sonography for the early detection of elbow injuries among young baseball players. A. J. R. 187:1436, 2006. 11. Keats, T. E.: An Atlas of Normal Roentgen Variants That May Simulate Disease, 5th ed. St. Louis, Mosby-Year Book, 1992, p. 395. 12. Kijowski, R., and De Smet, A. A.: MRI findings of osteochondritis dissecans of the capitellum with surgical correlation. A. J. R. 185:1453, 2005. 13. Markowitz, R., Davidson, R. S., Harty, M. P., Bellah, R. D., Hubbard, A. M., and Rosenberg, H. K.: Sonography of the elbow in infants and children. A. J. R. 159:829, 1992. 14. McCauley, R. G. K., Schwartz, A. M., Leonidas, J. C., Darling, D. B., Bankoff, M. S., and Swan, C. S. 2nd: Comparison views in extremity injury in children: an efficacy study. Radiology 131:95, 1979. 15. Merten, D. F.: Comparison radiographs in extremity injuries of childhood: current application in radiological practice. Radiology 126:209, 1978. 16. Rodgers, L. F.: Radiology of Skeletal Trauma. New York, Churchill Livingstone, 1982, p. 435.

Chapter 12 Imaging of the Pediatric Elbow

17. Schmidt, H., and Freyschmidt, J.: Köhler/Zimmer Borderlands of Normal and Early Pathologic Findings in Skeletal Radiology, 4th ed. New York, Thieme Medical Publishers, 1993. 18. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the capitellum. J. Bone Joint Surg. 61A:244, 1979. 19. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the radial head and neck. J. Bone Joint Surg. 64A:1153, 1982.

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20. Silberstein, M. J., Brodeur, A. E., Graviss, E. R., and Luisiri, A.: Some vagaries of the medial epicondyle. J. Bone Joint Surg. 63A:524, 1981. 21. Silberstein, M. J., Brodeur, A. E., Graviss, E. R., and Luisiri, A.: Some vagaries of the olecranon. J. Bone Joint Surg. 63A:722, 1981.

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CHAPTER

13

Congenital Abnormalities of the Elbow Peter C. Amadio and James H. Dobyns

somal syndromes, from the common dislocation of the radial head69 through fairly well-known syndromes such as trisomy 18, fibrodysplasia ossificans progressiva and the Antley-Bixler syndrome7 to such rarities as the Bruck syndrome (osteogenesis imperfecta with congenital joint contractures) and a congenital mirror movement syndrome. In some cases, the specific gene locus has now been identified; for example, elbow synostosis may also occur in the context of the multiple synostosis syndrome,53 which has been reported in large family groups and is the result of mutations in genes controlling TGF-β synthesis, including noggin, a protein believed to be important in establishing morphogenic gradients.

INTRODUCTION

CLASSIFICATION

Elbow function and configuration are affected by conditions both proximal and distal to the elbow as well as abnormalities at the elbow itself. With this proviso, this chapter discusses congenital anomalies of the region between the shaft-metaphyseal junction of the humerus proximally and the bicipital tuberosity distally, and reviews the current state of knowledge for evaluation and treatment in that region.

A multitissue defect classification can be based on the most obvious and most inhibiting tissue defect known to be present. Some degree of defect in other tissues is also commonly noted. The classification consists of three major categories: (1) bone and joint anomalies, (2) soft tissue anomalies, and (3) anomalies involving all tissues. Bone and joint abnormalities at the elbow may include major absences, but more commonly the skeletal structures are present but malformed. The common bone and joint problems are synostosis (Fig. 13-1), ankylosis (Figs. 13-2 to 13-4), and instability (Fig. 13-5). Soft tissue anomalies include malformations with contractures, control deficiencies, isolated tissue anomalies (Fig. 13-6), and congenital tumors (Fig. 13-7). Complete absence or disorganization of the whole limb, including elbow structures, may occur, as in phocomelia (Fig. 13-8); usually, recognizable though dysplastic structures are present (Fig. 13-9). Similar involvement, although more isolated to the elbow area, occurs in the pterygium syndromes. With reference to the bone and joint deformities only, it has been useful to many authors to classify them as congenital, developmental, or post-traumatic. As noted earlier, there is much confusion and interplay between these diagnoses, particularly with reference to radial head subluxation or dislocation. In this classification, congenital refers to a primary genetic dysplasia of the skeletoarticular structure of the elbow, resulting in an observed deformity. Other congenital anomalies or a familial history of similar anomalies help confirm this as an etiology. Developmental refers to elbow skeletal structures that are relatively normal at birth but that are then secondarily deformed by abnormal stresses (perhaps from a congenital shortening of the ulna); by paralysis or other limited motion (arthrogryposis); neural, metabolic, endocrine or dyscrasia disturbances (hemophilia, loss of pain recognition, hemochromatosis, and so on); tumor or hamartomatous involvement

CAUSES OF CONGENITAL ANOMALIES The causes of congenital elbow anomalies follow the same patterns of genetic or somatic damage to the embryo that are seen in other congenital anomalies. Often the most difficult problem is to decide whether the presenting deformity is entirely congenital or perhaps developmental or possibly even traumatic, and whether one or more of these etiologies are interacting. The most common condition in which this difficulty arises, radial head subluxation or dislocation, may be congenital, developmental, or post-traumatic. If it is not present at birth, it may be induced by a relatively trivial injury or merely by a short ulna from any cause. Because so much of the elbow area is cartilaginous at birth, it is difficult to rule out trauma as a possible agent in some dislocations and deformities. In addition, infections, tumors (congenital or infantile), and diseases (e.g., hemophilia) occasionally involve the elbow and may simulate congenital anomaly. Conditions that commonly involve the elbow are constitutional diseases of bone, metabolic abnormalities, and syndromes featuring limb formation and differentiation failures36,38,43,54,82,90 (Table 13-1). Some of the syndromes can be grouped under broad categories such as osteochondrodysplasia,3,29,33,90 dysostoses,18 primary growth disturbances, primary metabolic abnormalities, and congenital myopathies. Most, however, are chromo-

Text continued on p. 190.

Chapter 13 Congenital Abnormalities of the Elbow

TABLE 13-1

185

Elbow Deformities in Congenital Syndromes Syndrome Characteristics

Catalog Numbers*

Inheritance

Number of Patients†

1. Achondroplasia

O-1

10080

ASD

>100

2. Mesomelic dwarfism

O-1

15623, 24970

ASD, ASR

>100

3. Nievergelt

O-1

16340

ASD

100

5. Ellis—Van Creveld

O-1

22550

ASR

100

32. Acrofacial dyostosis (Nager)

15440

S, ASD

>50

33. LADD

14973

ASD, S

100

35. TAR

27400

ASR

>100

36. Auriculo-osteodysplasia

10900

ASD

100

38. Phocomelia

26900

ASR

50

40. Oculomelic complexes

16420, 25790, 25792, 16430, 25795, 16431

ASD, ASR

41. Otopalatodigital

31130

X

50

47. Split hand

18360

ASD

>100

48. Ulnar mammary

19145

ASD

100

Syndrome

Syndrome Characteristics

ASD, autosomal dominant; ASR, autosomal recessive; LADD, lacrimo-auriculo-dento-digital syndrome; D-1, dysostosis with cranial and facial involvement; D-2, dysostosis with predominant axial involvement; D-3, dysostosis with predominant extremity involvement; O-1, defects of growth of tubular bones; O-2, disorganized development of cartilage and fibrous skeletal elements; O-3, abnormalities of diaphyseal cortical density or metaphyseal modeling; PMA, primary metabolic abnormalities; PGD, primary growth disturbances; S, sporadic; T, teratogenic; TAR, thrombocytopenia and absent radius; VATER, vertebrae, anus, trachea, esophageal, renal; X, linked to sex chromosome. *Catalog numbers are those used in McKusick, V. A.: Mendelian Inheritance in Man, 6th ed. Baltimore, Johns Hopkins University Press, 1983. † Approximate number so far reported.

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FIGURE 13-1

A, Lateral and (B) anteroposterior x-ray views of a hypoplastic distal humerus and an apparent radial head subluxation certainly reveal a deformity but probably not a subluxation. Clinically, there was no evidence of a dislocated radial head. C, The opposite elbow showed a radiohumeral synostosis and also a recent fracture just proximal to the synostosis. This case demonstrates the difficulties of differentiation between subluxation, dislocation, and synostosis about the elbow, but the etiology is clearly congenital.

Chapter 13 Congenital Abnormalities of the Elbow

189

FIGURE 13-2

This anteroposterior view of an elbow in congenital ulnar dimelia shows no radiohumeral joint but two ulnohumeral joints. The appearance is unusual as expected, but no dislocation is noted. Motion of the elbow and forearm is limited by more than 50%.

FIGURE 13-3

A, Elbow and forearm function are, to date, nearly normal in this teenage boy in whom the anteroposterior x-ray view shows ulnar hypoplasia and bowing, distortion of the distal ulnar physis-metaphysis, and subluxation of the radial head. B, The lateral x-ray view shows a similar epiphysis-physis-metaphysis distortion of the proximal ulna with associated joint surface irregularity and shaft bowing. No diagnosis has been confirmed, but this is probably an osteochondrodysplasia. The elbow abnormalities are developmental.

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FIGURE 13-5

This case further demonstrates the overlap between congenital and developmental abnormalities of the elbow. Gradual radial head subluxation due to unequal length of forearm bones is well known in multiple exostosis. These anteroposterior and lateral xrays demonstrate a severe dislocation of the radial head that was present at birth and was associated with a severe osteochondroma deformity of the distal ulna with inhibition of ulnar growth.

FIGURE 13-4

A, This 18-month-old infant with chondrodysplasia punctata has developmental contractures of many joints including the elbows, where broad metaphyses and irregular, calcified epiphyses (B) are seen.

tion, but it often is not. A radial head subluxation or dislocation in an elbow with normal, neural, muscular, and skeletal structures in both elbow and forearm is post-traumatic until proven otherwise; such an elbow with abnormal skeletal forearm structures is probably due to developmental stresses, but additional trauma may play a part. Such an elbow with a synostosis from birth or other skeletal deformity and no evidence of peri-birth trauma is due to congenital causes, but again, trauma may be an additional factor. The confusions highlighted by this classification have been much discussed in the literature.14,20,38,45,51,54,61,70,71,72,79

DIAGNOSIS BONE AND JOINT ANOMALIES

(fibromatosis, osteochondromata, and so on), and disease (sickle cell anemia, Gorham’s disease, infections). The post-traumatic etiologic grouping is included in this chapter only because of the continuing confusion over early radial head dislocations, which are often posttraumatic, either as a variant of Monteggia fracture dislocation or as a pure dislocation of the soft cartilaginous radial head pulling through the annular ligament (see Chapter 20) and its residua. Both early and late, dislocation of the radial head is often diagnosed as a congenital subluxation or disloca-

Synostosis Synostoses may occur between all or any two of the three bones present at the elbow. The most common synostosis is that between the radius and the ulna proximally in the forearm, near the elbow (Fig. 13-10), but these two bones also may be joined at any point in their paired course in the forearm. Mital55 has classified these synostoses as type I, proximal to the proximal radial physis, and type II, distal to the proximal radial physis. Type II synostoses are more likely to be

Chapter 13 Congenital Abnormalities of the Elbow

FIGURE 13-6

A, Congenital aplasia of skin and soft tissues at the elbow and proximal forearm results in (B) developmental bone changes in the forearm and elbow.

FIGURE 13-7

A, The anteroposterior (AP) and lateral x-rays of the elbow and forearm in a patient with juvenile fibromatosis reveal marked enlargement of the ulna, posterolateral subluxation of the radial head, moderate enlargement of the distal humerus, and surface irregularities at all aspects of the joint. The changes in the elbows are developmental. B, A much more typical congenital posterior radial head dislocation is revealed in these AP and lateral views (A) and (B) of the elbow of a 14-year-old male with nail-patella syndrome and restricted elbow-forearm motion: 30 to 155 degrees flexion extension; 45 degrees supination; 60 degrees pronation. His mother has the same diagnosis and the same problem.

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humeroradial type is most common, followed by humeroradioulnar and humeroulnar types.52 However, anatomy is not the whole story, and McIntyre and Benson52 have proposed an etiologic classification of developmental elbow synostoses, specifically as to whether the synostosis occurs with (class I, or bony type) or without (class II, or joint type) limb hypoplasia. Within each class, the synostosis can be further characterized as occurring in a sporadic or familial pattern and, if familial, with dominant or recessive inheritance. In familial cases, the condition is usually bilateral.12 One of the more dramatic presentations is in the Antley-Bixler syndrome, an autosomal recessive disorder characterized by radiohumeral synostosis, cranial synostosis, midface hypoplasia, and a variety of urogenital and cardiac abnormalities (Fig. 13-10C).7 Distal radioulnar dislocation is a common accompaniment of many of these syndromes.

Ankylosis

FIGURE 13-8

This radiograph of the upper limb of a patient with congenital phocomelia shows a fairly welldeveloped shoulder and arm, a very hypoplastic hand, and fusion of all elbow elements with the short ulna protruding at right angles to the radius and forearm.

associated with congenital dislocation of the radial head.45 Cleary and Omer12 suggested a four-level classification scheme, in which Type I is clinically but not radiographically fused with a reduced normal-appearing radial head; Type II is similar but with a clear, bony synostosis; Type III has a hypoplastic posteriorly dislocated radial head; and Type IV has a hypoplastic anteriorly dislocated radial head. Type III appears to be the most common deformity and the one most likely to be associated with significant rotational deformity (almost always pronation). In addition, radiohumeral synostosis, ulnohumeral synostosis, or synostosis among the radius, humerus, and ulna may be present; often, the synostosis is in association with other limb abnormalities, the most common of which is probably ulnar deficiency.30,31,42,57,84 Synostosis may also be associated with fetal alcohol syndrome.84 Incomplete synostosis may occur, but often, this is a radiologic appearance rather than an actual occurrence, because complete radiographic synostosis is usually present by maturity.27,38,50,82 Cleary and Omer’s five cases of type I synostosis are, however, genuine; all of the patients were skeletally mature at the time of final clinical and radiologic review.12 Synostosis between the humerus and either the radius, ulna, or both is less common. Of these, the

Partial ankylosis of the elbow or the proximal radioulnar joint is often overlooked because limited elbowforearm motion is common in infancy28 and often not remarked in childhood. Causes include failure of complete synostosis, intrinsic abnormalities of the joint or surface formation mechanism, and abnormalities of the surrounding soft tissues, as occurs in pterygium cubitale. The joint must be formed correctly, must have adequate surface material and ligamentous support, and must move soon after its formation, or it will become ankylosed, as occurs, for example, in arthrogryposis, or, far more rarely, in Apert’s syndrome.35,89 There are instances when all or part of the elbow appears to be dislocated but proves to be only malformed and limited in motion (Fig. 13-11). Patients with dysplasia, such as those with Apert’s syndrome, may show a progressive loss of motion over time.89

Instability True congenital elbow instability seldom resembles the post-traumatic condition, but the two are often mistaken for each other. Congenital ulnohumeral dislocation is infrequent except in severe multitissue hypoplasia such as phocomelia, severe ulnar hypoplasia, and severe pterygium syndrome. The most common problem of instability at the elbow is that of radial head subluxation or dislocation.1,2,11,20,22,25,38,47,48,61,64,67,78,79 When subluxation is an isolated phenomenon, there is considerable doubt about whether it is congenital, developmental, or post-traumatic.14,20,38,45,51 The pulled elbow of infancy is a wellknown clinical problem that is associated with trivial trauma and laxity or minor tears of the annular ligament.61,70,72,75 Children have been seen at birth or shortly thereafter with similar problems.14,61,75 Furthermore, such

Chapter 13 Congenital Abnormalities of the Elbow

FIGURE 13-9

A, In another instance of generalized congenital hypoplasia of the upper limb, all segments from the shoulder girdle through the hand are equally and severely affected. B, Synostosis of all components of the elbow is present (C), correlated with a hypoplastic and asymmetric forearm plus a hypoplastic hand. D, Hypoplasia of the arm, shoulder, and shoulder girdle is also obvious on this radiograph.

193

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Part IV Conditions Affecting the Child’s Elbow

FIGURE 13-10

A, X-ray view of a typical congenital proximal, radioulnar, synostosis. B, The lateral view of the same synostosis is seen but demonstrates no radial head posterior subluxation, although this is commonly seen. C, Oblique view of the typical congenital radiohumeral synostosis of the Antley-Bixler syndrome.

subluxations in the infant, if not treated by closed reduction or other means, may result in deformities similar to those described as indicative of congenital dislocation of the radial head. It has been said that the degree of deformity in the few cases of known infantile dislocation that have been left untreated but followed suggest that the resulting deformity is milder than that seen in definite congenital hypoplasia at the elbow. This may be so but the so-called criteria for classifying a radial head dislocation as congenital (see later) may be seen after any early radial head dislocation regardless of cause (Fig. 13-12). By contrast, when traumatic dislocation is unreduced in the older child, the development of the radial head and the capitellum remains fairly normal, displaying only minimally those radiographic features said to be characteristic of congenital radial head dislocation. These features are (1) a dislocated or subluxed radial head, (2) an underdeveloped radial head, (3) a flat or dome-shaped radial head, (4) a more slender radius than normal, (5) a longer radius than normal, (6) an underdeveloped capitellum humeri, and (7) a lack of anterior angulation of the distal humerus.4,20,56,63,88 Bilaterality, especially symmetric bilateral dislocation, is

usually also considered evidence of a congenital etiology, but this is not an absolute requirement.48 However, many if not all the features of congenital dislocation can also be seen with developmental dislocation, due to mild degrees of ulnar or capitellar hypoplasia. In such cases the radial head may slowly dislocate with growth, as the paired forearm bones continue to grow at dissimilar rates.4 There may be only one absolute criterion of congenital elbow dislocation—dislocation with severe hypoplasia of all the osseous elements of the elbow. Absence of the capitellum is probably an example of congenital aplasia, but hypoplasia of the capitellum may occur after dislocation from any cause, as may a deformity of the radial head (see Chapter 20). When radial head dislocation is familial, bilateral, or seen at birth, or when it occurs with other musculoskeletal anomalies, particularly anomalies in the same upper limb, the evidence is strong that the radial head dislocation is congenital. Cases that are diagnosed later in life may be associated with a discrepancy in length of the paired forearm bones and, therefore, may fall within the “developmental” category. It is well known

Chapter 13 Congenital Abnormalities of the Elbow

195

FIGURE 13-11 A, Anteroposterior (AP) x-ray view of an apparent radiohumeral dislocation similar to that shown in Figure 13-2 is seen preoperatively. B, A postoperative AP x-ray view 4 years later shows repositioning of what was determined to be a congenital displaced radiohumeral joint without a dislocation of the radial head. C, A lateral postoperative view of the same elbow. Repositioning was obtained when the radius was shortened by removing a segment of the radial shaft. This segment of excised radius was then used to block the repositioned lateral condyle in its new position. This surgical procedure improved the x-ray position of the elbow but did not change function, which demonstrated both preoperatively and postoperatively mild loss of extension-flexion and moderate loss of supination-pronation.

that inadequate length of the ulna from any cause will result in increased compressive stresses along the radius, gradually leading to a subluxation and perhaps a dislocation of the radial head.38,47,79 Such subluxations, therefore, also may be a secondary phenomenon.48 Approximately half of all patients with isolated congenital radial head dislocation will have a problem bilaterally.2,48,56 Bell and associates4 have classified isolated

congenital dislocations of the radial head as type I, subluxation; type II, posterior dislocation with minimal displacement; and type III, posterior dislocation with significant proximal migration of the radius. Type I is the least common dislocation but the one most likely to be associated with pain. Types II and III appear to be roughly equally prevalent. Type III is associated with the most loss of motion, usually supination. Deformity

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Part IV Conditions Affecting the Child’s Elbow

These anomalies have been subdivided into syndromes with contractures (pterygium syndromes, congenital muscular atrophy and myopathy syndromes), control deficiencies, isolated tissue anomalies (triceps absence or contracture), and congenital soft tissue tumors.

Contractures The classic malformation with contracture is pterygium cubitale, in which almost every soft tissue is abnormal and a severe flexion contracture exists.23,24 The condition also has been called cutaneous webs and webbed elbow; it is but one manifestation of a congenital syndrome that may affect the neck, axilla, elbow, knee, or digits. A survey of 240 cases of cutaneous webs reported in the literature included 29 in the region of the elbow.23 The web may be unilateral or bilateral, or symmetric or asymmetric. The condition has been reported to result from both an autosomal dominant and a recessive gene. Associated abnormalities involving almost every body system have been reported.38,82 Other conditions resulting in formidable contractures about the elbow include fibrodysplasia ossificans progressiva and arthrogryposis.

Control Deficiencies

FIGURE 13-12 Anterior dislocation of the radial head is demonstrated at initial diagnosis (age 2 weeks), at age 4 months, and at age 11 years. In addition to the dislocation, there is a reversal of the ulnar curve and some convexity of the radial head. The etiology is probably post-traumatic.

of the radial head without subluxation also has been reported.22 Finally, Wiley and colleagues86 have reported congenital anterior and lateral dislocations.

Other Bony Problems Hypoplasia of the distal humerus may occur; the resulting deformity may cause ulnar neuropathy, either immediately, from synovial cysts, or chronically, due to abnormal elbow growth and nerve traction.74 Congenital pseudarthrosis of the olecranon has been reported but is exceedingly rare.66

SOFT TISSUE ANOMALIES Soft tissue anomalies or absences may interfere with elbow function as much as bone or joint deformities.

Arthrogryposis and its related syndromes are also included in this group but also are discussed elsewhere (see Chapters 71 and 72). Both flaccid and spastic palsies affect elbow control and range of motion. Simple absences or deficiencies of tissue also affect elbow control. Hypoplasia of the elbow includes deficient growth not only of osseous structures but also of the related soft tissue control elements and cover structures.13,58,81 Most characteristic is probably the extension contracture of arthrogryposis.87

Isolated Tissue Anomalies The skin may be deficient or missing, with absence, hypoplasia, or scarring of the underlying tissues. Nerve, vascular, and lymphatic anomalies in the region of the elbow are common.38 The anconeus epitrochlearis occasionally is present as an anomalous muscle and may cover the ulnar nerve in the cubital tunnel area, contributing to the possibility of entrapment. Other anomalous muscles that may cause nerve entrapment problems are (1) Gantzer’s muscle, an anomalous head of the flexor pollicis longus or flexor profundus that usually originates from the medial epicondyle or the coronoid process of the ulna and occasionally is a factor in anterior interosseous nerve compression; (2) a solitary head of the supinator and other anomalies of this muscle; (3) accessory muscles of the anterolateral aspect of the elbow, including the accessory brachialis or accessory brachioradialis; (4) variations in the head, origin, or insertion of the pronator teres; (5) variations of a similar

Chapter 13 Congenital Abnormalities of the Elbow

nature in the flexor carpi radialis, the flexor carpi ulnaris, and the palmaris longus53; and (6) an aberrant medial head of the triceps, which may snap over the medial epicondyle and irritate the ulnar nerve.16

Congenital Soft Tissue Tumors Tumors of the soft tissue are rare but include a wide variety of abnormalities, ranging from overgrowth to neoplasms and from multitissue hamartomas to single tissue entities. Probably the two most common tumors in the infant are the fibromatoses and vascular tumors. If the elbow area is involved, there is usually some limitation of motion.

COMBINED BONE AND SOFT TISSUE ANOMALIES Soft tissue anomalies may coexist with mild osseous anomalies, such as those related to the supracondyloid process.13,53,80 The supracondyloid process is an anomalous bony prominence extending from the anteromedial aspect of the distal third of the humerus. Struthers81 in 1848 described the ligament associated with this process, and since then, various anomalies have been reported in connection with it. These include a more proximal branching of the ulnar artery off the brachial artery above the bony spur, a more proximal insertion of the pronator teres on the bony process, and various relationships of the neurovascular structures with bone and ligament. The symptoms—pain, tingling, numbness, and so on—usually are neuralgic, but they may be vascular. Many of the congenital anomalies already discussed are manifest in both osseous and soft tissues. These abnormalities may be equivalent as in the supracondyloid process syndrome just discussed, or predominantly in one tissue, as in fibromatosis. More severe changes are seen with severe pterygium cubitale and severe forms of ulnar hypoplasia and phocomelia. In pterygium cubitale, or congenital webbed elbow, a skin web extends from the upper arm across the volar elbow to the forearm. Flexion is usually possible, but extension, pronation, and supination are severely limited. The muscles and neurovascular structures are incompletely developed. The bones are hypoplastic and deformed, and the elbow joint often is dislocated or severely hypoplastic. Fibrous strands represent missing muscles or tendons. Muscle hypoplasia is present posteriorly as well as anteriorly. Severe ulnar hypoplasia is marked by radial head dislocation, diminishing segments (ranging from small to nonexistent) of the proximal ulna, variable but seldom normal motion and stability, and muscle and neurovascular abnormalities. Conditions are more normal proximal to the elbow, but distally, more abnormalities are apparent; the ulnar forearm and hand structures are

197

particularly dysplastic. Lorea et al46 have proposed a classification of these findings based on a review of their own experience with 46 patients and a literature review. They propose three elbow types: type 1, normal; type 2, radiohumeral synostosis; and type 3, radial head subluxation. They further recommend subclassifying the elbows as having extension (type E) or flexion (type F) contractures. Unfortunately, they do not give the distribution of these types in their series. Phocomelia may present with similar findings, or the elbow may be even more dysplastic or absent altogether (hand, wrist, or forearm may be attached directly to the shoulder or trunk).

TREATMENT OF BONE AND JOINT DYSPLASIAS TREATMENT OF SYNOSTOSIS The treatment of synostosis of the elbow joint, whether radiohumeral60 or ulnohumeral, is dictated by the position of the forearm-wrist-hand unit and the function of the wrist-hand unit. These treatments have changed little over the past few decades. If the hand is absent or nonfunctional, repositioning of a synostotic elbow is clearly less important. If the hand is functional and the elbow is in a “functional” position (i.e., somewhere near midflexion), especially if the contralateral limb is normal, no treatment is likely to be necessary. For bilateral synostoses, some consideration probably should be given to positioning one arm in relative flexion and the other in relative extension. Frequently, only one forearm bone is well represented, and this may be bowed or deformed in some manner as well as short. In addition, there may be a rotational deformity. The forearm-wrist-hand unit may point directly posterior when the upper limb is in its usual dependent position beside the torso. Although simple rotational deformities can be corrected by osteotomy at any level, multiplane deformities should be corrected at the site of maximum deformity—that is, the humeral-forearm junction—perhaps extending the correction distally in the forearm (Fig. 13-13). One such method involves a posterior approach and a multiplesegment corrective osteotomy, making one or more of the segments trapezoidal in shape and rotating it 180 degrees, if necessary, to realign the unit as desired. If only one limb is involved, this desired position is usually at maximum length, with the forearm, wrist, and hand in the midposition. Derotation should be accomplished in the direction that causes the least torsion of the neurovascular structures, commonly from an internally rotated position through a clockwise rotation to a forearm midposition. Hyperextension, if present, is cor-

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FIGURE 13-13 A, Typical congenital radiohumeral synostosis with marked curving of the radial segment. B, A “shish kabob” corrective osteotomy was carried out with temporary internal fixation. Excellent correction resulted, and there were no complications. The elbow synostosis resulted in a posterior pointing forearm, wrist, and hand.

rected simply to neutral or slight flexion, and the osteotomy segments are adjusted to make the best contact in the desired position; a segment may be excised if this is needed for contouring. If both limbs are involved, enough elbow flexion angle should be included on one side to allow one of the limbs to reach the face and the head. Arthroplasty has been attempted30,31,39,57 but with indifferent results; the usual result is recurrence. Proximal forearm synostosis may occur with elbow synostosis, in which case the elbow is derotated as described previously. If, however, proximal radioulnar synostosis occurs in the presence of a functioning elbow joint, derotation of the forearm alone may be required. The indications for this procedure seem limited. Most patients have little functional deficit.12 Compensatory rotation at the wrist appears to be an important factor in minimizing symptoms.62 Although many authors have attempted and a few have claimed success for passive and even active mobilization of the forearm,8,15,19,27,37,55 there is no body of literature that substantiates these results in a significant number of patients who have been followed for an adequate period of time. When attempted, these procedures usually involve excision of the proximal radius, including the synostotic mass; division of the entire length of the interosseous membrane; interposition of some material between the contact areas of the radius and the ulna;

and tendon transfers, such as rerouting the extensor carpi radialis longus to the volar wrist for supination and the flexor carpi radialis to the dorsal wrist for pronation. A similar procedure involving the interposition of a metallic swivel has been described by Kelikian and Doumanian,37 but few long-term results have been reported. A more reliable procedure is that of derotation osteotomy.27,76 This procedure is best outlined by Green and Mital,24,55 who perform the rotational osteotomy through the synostosis itself. It is indicated primarily when the forearm is fused in the extreme of either pronation or supination; forearms synostotic in neutral or close to neutral function well and often are diagnosed only later in infancy or childhood because of this fact. The synostosis is approached through a dorsal incision and is transversely osteotomized. A radioulnar (in the coronal plane) K-wire or Steinmann pin is then placed distal to the osteotomy site and is left protruding externally on both sides. A longitudinal (in the sagittal plane) pin is then placed from the olecranon across the osteotomy site, and corrective rotation is carried out as desired. Because the indication is an extreme pronated or supinated position, in most instances, 70 to 90 degrees of rotation from pronation toward supination is required. If circulatory deficits appear during or after this derotation, less rotation is accepted, although an additional

Chapter 13 Congenital Abnormalities of the Elbow

amount may be carried out 10 to 15 days later. The radioulnar pin may be fixed by either a plaster cast or an external fixation apparatus. Internal fixation should not be used because alteration of forearm rotation may be necessary to diminish circulatory difficulties. Goldner and associates21 claim that these circulatory problems may be minimized by the use of derotation in the distal forearm (radius only in younger patients; radius and ulna in older patients). Their results have yet to appear in the literature except in abstract form, but the rationale seems reasonable and the technique appropriate. They recommend cross-pin fixation in children and plate fixation in adolescents and adults. One new and unusual problem has been reported recently, as an acute sequela of proximal radioulnar synostosis: flexion contracture. Matsuko et al49 have reported five cases in which an acute hyperflexion episode had resulted in the sudden onset of a fixed flexion contracture in teenaged boys (in four of the five cases). In each case, the problem was treated surgically. Through a lateral approach, the anterior elbow capsule was identified. In each case, a thickened band of anterior capsule was identified, under which the hyperflexed, anteriorly displaced radial head had become trapped. A simple excision of the band resulted in complete correction in each case.

TREATMENT OF ANKYLOSIS Ankylosis that does not involve synostosis, subluxation, or dislocation of the elbow may occur. Paralyses, muscle disease, and other soft tissue abnormalities commonly restrict motion; treatment of these abnormalities is discussed elsewhere (see Chapters 71 and 72). Abnormalities of joint shape and joint cartilage occur but are usually treated only by physical therapy. Rotation ankylosis due to soft tissue abnormalities occurs but has minimal effect on the elbow; its treatment requires release not only of the proximal radioulnar area but also in the forearm and wrist.5

TREATMENT OF INSTABILITY Treatment of infantile dislocations of the radial head, whether congenital, developmental, or traumatic, depends on the degree of hypoplasia present in the forearm and elbow area. If in doubt about the configuration of the various components of the elbow joint, an arthrogram should be performed61; this study may show that there is no dislocation at all but merely a deformed elbow joint with the radiocapitellar joint displaced from the usual position (see Fig. 13-12). Attempts at open reduction have been made, but the result is often recurrence unless both annular ligaments and ulnar length/ configuration are restored (Fig. 13-14). Most authors do

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not advise the procedure,4,56,86 although recently Sachar and Mih71 have reported good short-term results (maintenance of reduction and improved forearm rotation) in 10 of 12 children with congenital radial head dislocation operated on between ages 7 months and 6 years. They reported that the most common finding was an interposition of the annular ligament, which they divided and then repaired in its anatomic position. Follow-up was short, however, averaging less than 2 years, with the longest being only 41 months. The alternative to attempted reduction of congenital or infantile radial head dislocation is to accept the imposed disability (some limitation of forearm rotation, ranging from a few degrees to more than 90 degrees; occasional limitation of elbow motion; and infrequent pain) and proceed with radial head excision, if needed, at maturity.19-21,38,48,79 As noted in a long-term follow-up study,4 painful arthritis is typical only of the least common type I deformity. Relief of pain and cosmesis are more likely to be benefited from surgical excision; motion is seldom improved.4

TREATMENT OF SOFT TISSUE DYSPLASIAS Treatment of most soft tissue problems at the elbow level is discussed in other chapters. Arthrogryposis, as well as other flaccid palsies, is covered in Chapter 71. Spastic neurogenic problems are discussed in Chapter 72, and nerve entrapment around the elbow is discussed in Chapter 80. Successful treatment for other soft tissue dysplasias at the elbow is rare. Aplasia cutis congenita has occurred in the elbow area. In the author’s experience, it was associated with scarring and hypoplasia of the regional forearm muscles plus reactive deformity of the underlying bones. Resurfacing with a skin and subcutaneous flap was eventually necessary, followed by tendon transfers, which in this instance were required to provide extensor function of the wrist and hand. Muscle anomalies may result in either mechanical problems (snapping or catching)16 or neurovascular entrapment, as discussed in Chapter 80.

TREATMENT OF COMBINED BONE AND SOFT TISSUE DYSPLASIAS Pterygium cubitale remains an unsolved challenge. Attempts at treatment have included Z-plasty, skin grafts, and release of other tight structures. Improvement has been limited, and risks are high.23,24 Because there is no substantial report in the literature describing a reliable and useful method of treatment, no recommendations for surgical treatment are offered. Techniques of bone shortening to permit a greater safe excursion of the

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FIGURE 13-14 A, Anteroposterior and lateral x-ray views of a radial head dislocation in a limb with other congenital anomalies but with a fairly normal skeleton at the elbow. Although this fulfills the requirements usually listed for congenital dislocation, the dislocation may simply be developmental, related to the unequal length of the two forearm bones. B, Postoperative lateral radiographs after open reduction of the dislocated radial head and internal fixation. A second operation was carried out a year later, at which time the radius was shortened and the annular ligaments were reconstructed; repeat reduction of the radial head also was performed.

neurovascular structures or techniques of vascular and nerve grafting have been attempted, but adequate reporting is not yet available. The lengthening-stretching techniques of Ilizarov have been tried by a few investigators, so far with limited success. The hands in pterygium cubitale are often deficient also, but because limited excursion of the elbow is available in flexion, at least they are usually able to reach the upper trunk, the face, and the head. In severe forms of ulnar dysplasia, the elbow often displays adequate range and stability. Occasionally, the displaced radial head is sufficiently limiting or symptom provoking so that treatment is offered. Although excision of the radial head and a sufficient portion of the shaft to resolve the mechanical block might suffice, the desire to stabilize and lengthen the forearm plus the fear of recurrent encroachment by the radial shaft usually lead to a recommendation for a one-bone forearm procedure (Fig. 13-15).9 This is carried out as follows: 1. Use a long lateral incision that covers the distal half of the arm, the elbow, and the proximal half of the forearm.

2. Mobilize the anterior flap, identify and protect the radial nerve, and identify and mobilize the anteriorly and radially dislocated radius. 3. Mobilize the posterior flap, identify the short ulnar fragment, and uncover the interosseous space. 4. With both bones visualized through both anterior and posterior intervals (obviously, the procedure can be performed through an anterior approach only or through both a proximal anterior and a distal posterior approach, but we have found that access and safety are preferable this way), the maximum forearm length that the soft tissue will accept is judged by manual displacement. 5. The radius then is osteotomized at the length just determined, and the proximal fragment is removed. 6. The distal fragment is aligned with the short ulnar fragment, and contact is maintained by an intramedullary pin drilled through the olecranon, along the ulnar medullary cavity, across the osteotomy site, and along the radial intramedullary space until it penetrates the radial cortex at some point. (The forearm position, usually the midportion, should be set before this distal penetration occurs.)

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FIGURE 13-15 A, A lateral view of an elbow in ulnar agenesis shows an apparent dislocation proximally and anteriorly of the radial head. Although the ulnar agenesis is congenital, the dislocation is probably developmental. Clinical findings suggested that this was a true dislocation. B, There is occasional need for excision of the dislocated radial head and combination of the proximal ulna and distal radius to form a one-bone forearm, as seen here. This changes both the appearance and the function of the elbow as well as the forearm (the range of motion of the elbow is usually improved; the forearm position becomes fixed).

7. The usual support dressings (long arm splint-dressing combination initially, perhaps changed to a long arm cast later for the older child) are used until healing occurs (4 to 6 weeks). The supports are then discontinued, and the pin is removed.

vention. As has been noted, many synostotic forearms function well, even if in a poor position owing to compensatory hyper-rotation at the wrist. Such factors need to be considered carefully before embarking on a surgical adventure.

In phocomelia, the elbow is seldom the site of the infrequent surgical attention given to this condition, but there may be an occasional indication for a one-bone forearm procedure or for simultaneous lengthening and stabilization at an unstable elbow segment.77

Unwarranted Treatment Due to Misdiagnosis

COMPLICATIONS Overtreatment In many cases, the severe upper limb anomaly, particularly if it is of the sporadic variety, is associated with a completely normal contralateral upper limb. In such cases, surgical treatment may have little effect on the long-term functional level of the patient.6 Therefore, it also is important to consider the likely practical gains from therapy before proposing an inter-

This problem, present in any medical management situation, is a particular hazard with congenital anomalies. In the infant, testing of the neurovascular supply, dynamic and static control elements, and structural and support elements is difficult and uncertain. Interpretation of radiographs, when so much of the skeletal tissue is still cartilaginous, is deceptive. Nevertheless, the best review possible is needed if surgery is contemplated. This may require examination under sedation or special radiographic techniques such as arthrography, computed tomography or magnetic resonance imaging studies, cineradiographic motion and stress studies, and others. It should be recalled that “hands-on” examination is particularly valuable in the child because much cartilage is not yet bone and much muscle and tendon can be palpated better than tested.

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Infection This is a serious problem after any surgical procedure, and the usual wound management preventive measures are employed. The ability to apply a splint dressing that will maintain the desired position and stay in place is important in infants, but must not override the need for wound inspection if infection is suspected.

Vascular damage due to direct insults, compartment pressure increase, or indirect damage from stretch or torsion does occur. The stretchtorsion injury is a particular risk in the corrective osteotomies used to treat synostosis. For this reason, circulation should be checked during the osteotomy procedure. For osteotomies in the proximal forearm or elbow, fixation that can be removed or adjusted to decrease vascular stress is necessary. The circulatory pattern in congenitally abnormal arms is almost always abnormal; if further, extensive alteration in anatomy is anticipated, preliminary angiography may be helpful. Doppler assessment before and during surgery is invaluable.

Vascular Compromise

Nerve injury due to dissection or compression at anatomic entrapment points during postoperative reaction, stretch, or torque stress also may occur. Torque stress usually can be monitored by assessing the effect of the stress on the vascular supply. The other possibilities are best controlled by adequate exposure and careful dissection. Regardless, close and skilled postoperative monitoring is essential.

Nerve Damage

Partial or total destruction of the physis may result from bone cutting, pin or other fixation, or damage to the local physis circulation. Care should be taken to avoid physeal damage, particularly because most such limbs are hypoplastic and short already. A pin passing near the center of and at right angles to the physis seems to run the least risk of serious damage.

Physis Damage

Incongruous, malformed, and abnormally surfaced joints are common with congenital problems, and the investing soft tissue, motor units, and even skin also may limit normal joint function. Therefore, careful preservation of the available joint structures is important; this includes avoiding pin breakage in the elbow joint. Many surgeons, for instance, fix the ulna and radius rather than the humerus and radius to minimize the chances of intra-articular pin breakage after radial head reduction. Recurring elbow or forearm stiffness after operations for congenital elbow area anomalies is the most depressingly common complication of all. Pharmacologic suppression of scar formation and early continuous passive motion for these tiny arms

Joint Damage

may help, and both treatments should be available in the future.

CONGENITAL ELBOW REDUX Can a topic be brought to life, or at least reinvigorated? These questions arise as the authors peruse their prior efforts and the literature since those efforts and note that little has changed. There is still uncertainty regarding the relative incidence of the two most common congenital problems at the elbow, radial head subluxation or dislocation versus proximal radio-ulnar synostosis. Treatment for radial head dislocation still runs the gamut from waiting for symptoms/disability, then removing the radial head10 to open reduction, which may vary from removal of the annular ligament from the joint and reconstructing it in normal position to open reduction, corrective osteotomy of the ulna and reconstruction of an annular ligament, similar to the methods used for similar problems in old Monteggia injuries.85 Usually, radioulnar synostosis continues to be treated by corrective osteotomy, although new methods have been designed with osteotomies of both the radius (distally) and the ulna (proximally) with immediate correction if the deformity is not too severe59 or staged correction for the severe deformities.44 The venturesome among us are still, case by case, trying synostosis excision and interposition of various substances, recently using a vascular fascio-fat graft.34 The association of radial head subluxation or dislocation with other conditions continues to be newsworthy with new reports including congenital pseudarthrosis of the forearm41 treated by a one-bone forearm procedure in one case26 and treated by resection and internal fixation plus a vascularized fibular graft in another case.68 There are many reports of radial head subluxation or dislocation with other conditions17,40,73 and with paralyses.65 It is well known that shortening of the ulna from any cause risks of subluxation or dislocation of the radial head, but the association with radial longitudinal deficiency (44% of extremities with type 1 [more than 2 mm. shortening of the radius] radial deficiency32) is not as well known. However, it is certain that there is a familial component to some instances of radial head dislocation.69 So, what has changed in the last decade in this troublesome arena? Very little, and this is also troublesome. The potential for advances is overwhelming. Stem cell manipulation, embryonic and fetal alterations, early and late childhood intervention offer different and, as yet, minimally explored options. Solutions to the unsolved problems will involve both biologic and biotechnology approaches, and probably combinations of the two. The authors believe that this niche area has been dormant long enough and anticipate a need for

Chapter 13 Congenital Abnormalities of the Elbow

both national and international interactions between all interested parties. In the next edition of this text, we hope to report on a tsunami of interactive investigations.

SUMMARY Congenital elbow dysplasia is a more common problem than is generally realized. If it is mild, elbow function is minimally affected; if it is severe, problems of the entire limb or the wrist and hand often take precedence. In the few instances, when the elbow abnormality is isolated and relatively severe, surgical assistance is available but is less than satisfying. The most common and provocative problem is that of radial head subluxation or dislocation, in which the abnormality may be due to one or more of three differing etiologies: congenital, traumatic, or developmental (resulting from congenital, traumatic, infectious, tumor, or other causes). Effective management protocols have been developed, but unsolved problems still abound.

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55. Mital, M. A.: Congenital radioulnar synostosis and congenital dislocation of the radial head. Orthop. Clin. North. Am. 7:375, 1976. 56. Miura, T.: Congenital dislocation of the radial head. J. Hand Surg. 15B:377, 1990. 57. Mnaymneh, W. A.: Congenital radiohumeral synostosis. A case report. Clin Orthop. 131:183, 1978. 58. Murakami, Y., and Komiyama, Y.: Hypoplasia of the trochlea and the medial epicondyle of the humerus associated with ulnar neuropathy. J. Bone Joint Surg. 60B:225, 1978. 59. Murase, T., Tada, K., Yoshida, T., and Moritomo, H.: Derotational osteotomy at the shafts of the radius and ulna for congenital radioulnar synostosis. J. Hand Surg. Am. 28:133, 2003. 60. Murphy, H. S., and Hansen, C. G.: Congenital humeroradial synostosis. J. Bone Joint Surg. 27:712, 1945. 61. Ogden, J. A.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1982, p. 319. 62. Ogino, T., and Hikino, K.: Congenital radioulnar synostosis: Compensatory rotation around the wrist and rotation osteotomy. J. Hand Surg. 12B:173, 1987. 63. Pfeiffer, R.: Die angeborene Verrenkung des Speichenkopfchens als Teilerscheinung anderer kongenitaler Ellenbogengelenkmissbildungen. Mensch Vererb Konstitutionslehre 21:530, 1938. 64. Phillips, S.: Congenital dislocation of radii. Br. Med. J. 1:773, 1883. 65. Pletcher, D. F., Hoffer, M. M., and Koffman D. M.: Nontraumatic dislocation of the radial head in cerebral palsy. J. Bone Joint Surg. 58:104, 1976. 66. Pouliquen, J. C., Pauthier, F., Kassis, B., and Glorion, C.: Bilateral congenital pseudarthrosis of the olecranon. J. Pediatr. Orthop. B 6:223, 1997. 67. Powers, C. A.: Congenital dislocations of the radius. J. A. M. A. 41:165, 1903. 68. Ramelli, G. P., Slongo, T., Tschäppeler, H., and Weis, J.: Congenital pseudarthrosis of the ulna and radius in two cases of neurofibromatosis type 1. Pediatr. Surg. Intern. 17:239, 2001. 69. Reichenbach, H., Hormann D., and Theile, H.: Hereditary congenital posterior dislocation of radial heads. Am. J. Med. Genet. 55:101, 1995. 70. Ryan, J. R.: The relationship of the radial head to radial neck diameters in fetuses and adults with reference to radial head subluxation in children. J. Bone Joint Surg. 51A:781, 1969. 71. Sachar, K., and Mih, A. D.: Congenital radial head dislocations. Hand Clin. 14:39, 1998. 72. Salter, R., and Zaltz, C.: Anatomic investigations of the mechanism of injury and pathologic anatomy of “pulled elbow” in children. Clin. Orthop. 77:134, 1971. 73. Sanatkumar, S., Rajagopalan, N., Mallikarjunaswamy, B., Srinivasalu, S., Sudhir, N. P., and Usha, K.: Benign fibrous histiocytoma of the distal radius with congenital dislocation of the radial head: a case report. J. Orthop. Surg. (Hong Kong) 13:83, 2005. 74. Sato, K., and Miura, T.: Hypoplasia of the humeral trochlea. J. Hand Surg. 15A:1004, 1990.

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75. Schubert, J. J.: Dislocation of the radial head in the newborn infant. J. Bone Joint Surg. 47A:1019, 1965. 76. Simmons, B. P., Southmayd, W. W., and Riseborough, E. J.: Congenital radioulnar synostosis. J. Hand Surg. 9:829, 1983. 77. Smith, R. J., and Lipke, R. W.: Treatment of congenital deformities of the hand and forearm, Part II. N. Engl. J. Med. 300:402, 1979. 78. Smith, R. W.: Congenital luxations of the radius. Dublin Q. J. Med. Sci. 13:208, 1852. 79. Southmayd, W., and Ehrlich, M. G.: Idiopathic subluxation of the radial head. Clin. Orthop. 121:271, 1976. 80. Stone, C. A.: Subluxation of the head of the radius: Report of a case and anatomical experiments. J. A. M. A. 1:28, 1916. 81. Struthers, J.: A peculiarity of the humerus and humeral artery. Month. J. Med. Sci. 28:264, 1848. 82. Temtamy, S. A., and McKusick, V. A.: Carpal/tarsal synostosis. Birth Defects 14:502, 1978. 83. Tubiana, R.: The Hand. Philadelphia, W. B. Saunders Co., 1981.

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84. Uthoff, K., and Bosch, U.: Die proximale radioulnare synostose im rahmen des fetalen alkoholsyndrom. Unfallchirug 100:678, 1997. 85. Wang, M. N., and Chang, W. N.: Chronic posttraumatic anterior dislocation of the radial head in children: thirteen cases treated by open reduction, ulnar osteotomy, and annular ligament reconstruction through a Boyd incision. J. Orthop. Trauma 20:1-5, 2006. 86. Wiley, J. J., Loehr, J., and McIntyre, W.: Isolated dislocation of the radial head. Orthop. Rev. 20:973, 1991. 87. Williams, P. F.: The elbow in arthrogryposis. J. Bone Joint Surg. 55B:834, 1973. 88. Windfeld, P.: On congenital and acquired luxation of the capitellum radii with discussion of some associated problems. Acta Orthop. Scand. 16:126, 1946. 89. Wood, V. E., Sauser, D. D., and O’Hara, R. C.: The shoulder and elbow in Apert syndrome. J. Pediatr. Orthop. 15:648, 1995. 90. Wynne-Davies, R.: Heritable Disorders in Orthopaedic Practice. Oxford, Blackwell Scientific Publications, 1973.

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CHAPTER

14

Supracondylar Fractures of the Elbow in Children Anthony A. Stans

INTRODUCTION Supracondylar humerus fractures are the most common fracture about the elbow in children and have the highest complication rate for elbow fractures in this age group.8,16,39 These compelling facts continue to pique the interest and hold the attention of orthopedists who treat pediatric patients. Since the last edition of this text, issues that have generated the most discussion regarding supracondylar fracture treatment concern timing of reduction and treatment as well as pin configuration used for fracture stabilization. Both issues are addressed in the body of this chapter.

INCIDENCE AND ETIOLOGY Supracondylar humerus fractures almost exclusively affect the immature skeleton.41,50 Eliason25 reported that 84% of supracondylar fractures occurred in patients younger than 10 years. The peak age for supracondylar humerus fracture has been reported to be between ages 6 and 7 years, and the left arm is injured more frequently than the right.* Previous reports have suggested that supracondylar fractures are common in boys, but more recent studies have documented an equal sex distribution.† Traditional teaching has held that the peak incidence for extension-type supracondylar humerus fractures occurs at approximately age 7 because that is the age of maximum elbow flexibility and hyperextension. This mechanism has been confirmed by research suggesting that a fall on a hyperextended elbow produces a supracondylar humerus fracture, whereas a fall on an outstretched arm without elbow hyperextension is more likely to cause a distal radius fracture.60 Hyperextension converts what would be an axial loading force to the *See references 13,20,22,40,41,50-52,54,59,76. † See references 38,40,56,57,61,70,75,80.

elbow into a bending moment. The tip of the olecranon acts as a fulcrum, causing the fracture to occur through the relatively thin bone of the olecranon fossa (Fig. 14-1). The distinctive shape of the humeral metaphysis with the medial and lateral condyles and columns, and the narrow midpoint of the olecranon fossa, adds to the instability of the fracture, particularly when there is rotation and tilting of the distal fragment.62,63 Knowledge of elbow anatomy is important to understanding the cause of the injury, and to understanding effective treatment principles (see Chapters 2 and 3). The stability of the elbow derives from bony and soft tissue structures.33,61,66 Soft tissue stability on the lateral aspect of the elbow is provided by an expansion of the triceps, anconeus, brachioradialis, and extensor carpi radialis longus. The thickened periosteum of a young child, both medially and laterally, is an important additional stabilizer of the fracture fragment and provides a medial or lateral hinge during attempted reduction (Fig. 14-2). Research by Khare et al45 has confirmed the importance of the triceps tendon’s acting as a tension band to achieve fracture stability in the flexed elbow. Because angular deformity is a common complication of these fractures, the normal variations in pediatric anatomy should be understood. The carrying angle of the elbow joint is the angle formed by the intersection of the longitudinal axis of the arm and the forearm (Fig. 14-3). The normal elbow is usually in slight valgus alignment, but this feature varies among children.1,17,77 Smith77 noted that, of 150 children aged 3 to 11, the carrying angle in boys averaged 5.4 degrees and ranged from 0 to 11 degrees, whereas in girls, it averaged 6 degrees and ranged from 0 to 12 degrees. Aebi1 observed that the measurements were not constant and changed as the child matured, tending to decrease in magnitude and in variation between children. Although not commonly associated with abuse in the past, a recent report found that 36% of patients younger than age 15 months at the time of their supracondylar fracture sustained the fracture as a result of abuse.79 Clinicians must exclude “nonaccidental trauma” as a potential cause of injury whenever an infant presents with a supracondylar humerus fracture.

CLASSIFICATION A classification system should guide treatment, provide information on prognosis, and facilitate research by ensuring that similar injuries are compared in the literature. The vast majority of supracondylar humerus fractures can be classified as either flexion or extension injuries, a distinction based on the radiographic appearance and the mechanism of injury. The distinction is important for treatment because the reduction

Chapter 14 Supracondylar Fractures of the Elbow in Children

FIGURE 14-1

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A, Transverse and sagittal sections of the distal humerus. The shaft diameter is large above the supracondylar foramen. B, However, if a cut is made through the supracondylar foramen, the “bicolumnar” nature of this region becomes evident, looking proximally (C) and distally (D). (From Ogden, J.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1983.)

FIGURE 14-2

An experimentally produced fracture shows the medial periosteal hinge and offers a glimpse of the posterior hinge. After reduction, the soft tissues hold the fragments in place. The better the reduction, the greater the security. (From Rang, M.: Children’s Fractures, 2nd ed. Philadelphia, J. B. Lippincott, 1983.)

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FIGURE 14-3

A, Change in the carrying angle cannot be detected when the flexed elbows are examined from in front. B, Change in the carrying angle is apparent, however, when the flexed elbows are examined posteriorly. On the right, the bone prominences (black dots) can be seen to have tilted medially. C, With the arms extended, a 25-degree varus deformity of the right arm can be seen in a 9-year-old boy 2 years after a supracondylar fracture of the right arm. There is no limitation of motion. Note that the normal carrying angle of the left arm is 0 degrees. D, When the varus elbow is acutely flexed, the hand points laterally, away from the shoulder joint. This view also demonstrates the medial tilt of the bone prominences. (From Smith, L.: Deformity following supracondylar fractures. J. Bone Joint Surg. 42A:236, 1960.)

maneuvers are essentially opposite for the two fracture types and flexion-type fractures are significantly more difficult to reduce by closed means. A small minority of fractures exhibit multidirectional instability and do not fit into either flexion or extension types.49 Recognition of multidirectional instability is helpful in formulating an effective treatment strategy.

FLEXION-TYPE FRACTURES Flexion-type fractures are the result of a direct fall onto a flexed elbow in which a powerful flexion force is applied to the distal humerus, usually through the olecranon. The distal humeral fragment is displaced anteriorly, and the fracture line crosses the humerus from the distal posterior to the proximal anterior aspect (Fig. 14-4). Flexion-type fractures are frequently completely displaced and are difficult to reduce by closed means. The reduction maneuver for flexion-type fractures involves elbow extension or involves using the forearm

to apply a posterior-directed force to the anteriorly displaced distal fracture fragment.

EXTENSION-TYPE FRACTURES Extension-type fractures typically occur as the result of a fall onto an outstretched arm with a hyperextended elbow. The fracture line traverses the distal humerus from the proximal posterior to the distal anterior aspect. Displacement varies from none to marked displacement with fracture fragments separated by interposed soft tissue. Numerous classifications systems have been devised for extension-type supracondylar humerus fractures,10,24,40,41,68 but the classification system attributed to Gartland31 is the most commonly accepted system in use today. As described by Gartland, the classification system is simple, reproducible, helpful in guiding treatment, and provides information on prognosis and potential complications. A very similar fracture classification system was published in the German literature of the early 20th century by Felsenreich.26

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FIGURE 14-4

A, Flexion-type supracondylar fracture with anterior and medial angulation. B, Lateral view. Note also that what appears to be an avulsion of the medial epicondyle is really due to the rotation of the distal humerus and the oblique orientation of the film.

TYPE I Type I fractures are nondisplaced (Fig. 14-5). In many patients, the fracture line may not be visible on injury radiographs, but the posterior fat pad sign, palpable tenderness in the supracondylar region, and an appropriate mechanism of injury allows the physician to establish a correct diagnosis. The diagnosis is often confirmed when periosteal callus is seen on radiographs taken 3 weeks after the injury. If recognized and treated appropriately, type I fractures should never be associated with neurovascular injury or malunion.

TYPE II In type II fractures, there is displacement or angulation at the fracture site, but a hinge of bone crossing the fracture keeps the fragments in continuity. The distal fragment is most often displaced posteriorly, and apex anterior angulation at the fracture site results in a hyperextension deformity (Fig. 14-6). Variations of type II fractures have also been described that involve medial impaction or rotation, which can result in cubitus varus if unrecognized (Fig. 14-7). Although there are reports

of neurovascular injury associated with type II fractures, such injuries are rare.69

TYPE III Type III fractures are completely displaced fractures in which there is no continuity between fracture fragments (Fig. 14-8). The distal fragment is displaced posteriorly and may be displaced medially or laterally as well. There is a much higher incidence of neurovascular complications with type III fractures, and soft tissue is usually interposed between fracture fragments. The brachialis muscle is most often interposed, but the median nerve, radial nerve, or brachial artery may also be entrapped.

DIAGNOSIS AND RADIOGRAPHIC EVALUATION We define a supracondylar humerus fracture to be a transverse fracture crossing the entire width of the distal humeral metaphysis without involving the distal humeral physis. The primary challenge in establishing this diagnosis is to rule out other fractures of the distal humerus

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FIGURE 14-5

A and B, Type I supracondylar fracture with an indistinct fracture line but markedly positive anterior and posterior fat pad signs. C and D, After 3 weeks of cast immobilization, fracture callus confirms the presence of a nondisplaced fracture.

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FIGURE 14-6

A, Type II supracondylar fracture with apex anterior angulation. B, When treated with flexion of the elbow and casting, the injury shows excellent early alignment.

that do not meet these criteria. Fractures that can sometimes be confused with supracondylar humerus fractures include lateral condyle fractures, medial condyle fractures, and transphyseal fractures. Establishing the correct diagnosis is most difficult in patients younger than 4 years, whose ossific nuclei of the distal humerus are yet unossified. Routine anteroposterior and lateral radiographs should be taken at 90 degrees to each other whenever a supracondylar humerus fracture is suspected. If the examiner is certain of the presence of a distal humerus fracture, because of focal point tenderness, mechanism of injury, and positive posterior fat pad sign, but is unable to identify the specific fracture pattern, 45-degree oblique radiographs often provide adequate visualization to establish the definitive diagnosis. On the other hand, if what may be a pathologic abnormality could possibly be a normal variant in a partially ossified distal

FIGURE 14-7

A, Schematic view of greenstick type II fracture that is causing medial trabecular-cortical compression leading to cubitus varus. This condition must be corrected with manipulation. B, Acute cubitus varus in a 5-year-old child with a type II fracture that was not corrected. C, Mild cubitus varus can be seen 2 years later. (From Ogden, J. A.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1982.)

humerus, comparison films of the opposite elbow allow identification of normal anatomy and determination of whether or not a fracture is present. Once a fracture is identified, the radiographic fracture classification system described earlier may be applied.

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FIGURE 14-8

A and B, Severe type III fracture with rotation and posterior and lateral displacement with associated neurovascular compromise.

The anterior and posterior fat pad signs are often helpful in diagnosing intra-articular elbow fractures such as supracondylar humerus fractures (see Chapter 15). Although it is very sensitive, the anterior fat pad sign is not very specific for intra-articular elbow fractures because the coronoid fossa of the humerus (occupied by the anterior fat pad) is much more shallow than the olecranon fossa (occupied by the posterior fat pad). Any insult that causes a joint effusion may cause the anterior fat pad to become visible on the lateral radiograph. A larger intra-articular fluid collection such as fracture hemarthrosis is necessary to displace the posterior fat pad enough for it to become visible on lateral radiographs; therefore, the posterior fat pad sign is much more reliable. Additional radiographic measurements have been described to assess fracture alignment before and after reduction. The most commonly used measurement is Baumann’s angle, the intersection of a line drawn along the longitudinal axis of the humerus and a line drawn along the physis between capitellum and distal lateral humeral metaphysis. The normal angle varies in magnitude but averages approximately 72 degrees, and it should always be compared with the uninjured contralateral elbow (Fig. 14-9).88 A second useful radiographic reference line is the anterior humeral line (Fig. 14-10). If the capitellar ossific nucleus is displaced posterior to the

FIGURE 14-9

Baumann’s angle is the angle formed by a line perpendicular to the axis of the humerus and a line tangential to the straight epiphyseal border of the lateral part of the distal metaphysis. In the case illustrated, Baumann’s angle is 80 degrees on the fractured left side and 70 degrees on the normal right side, indicating varus angulation of 10 degrees. The same holds true for lateral tilt and valgus angulation. (From Dodge, H. S.: Displaced supracondylar fractures of the humerus in children: treatment by dental extraction. J. Bone Joint Surg. 54A:1411, 1972.)

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TYPE I FRACTURES

FIGURE 14-10 The anterior humeral line (AHL). A, A line is drawn down the anterior humeral cortex. B, A second line is drawn perpendicular to the AHL from the anterior to the posterior extent of the capitellum and is divided into thirds. In normal cases, the AHL passes through the middle third of the capitellum. (From Rogers, L. F., Malave, S. Jr., White, H., and Tachdjian, M. O.: Plastic bowing, torus and greenstick supracondylar fractures of the humerus: radiographic clues to obscure fractures of the elbow in children. Radiology 128:146, 1978.)

anterior humeral line, fracture reduction should be considered. Fracture reduction should restore Baumann’s angle to a measurement similar to that of the opposite elbow on the anteroposterior view, and on the lateral view, it should restore the capitellum to a position in which the central third is bisected by the anterior humeral line. For all patients with supracondylar humerus fractures, the entire extremity should be examined and radiographs obtained of all areas where associated injuries might be present. Approximately 15% of patients with supracondylar fractures have an associated fracture in the ipsilateral extremity.86 Supracondylar fracture associated with a Montaggia lesion has also been reported.3,65

TREATMENT The goal of treatment is to obtain and safely maintain anatomic fracture alignment, promote rapid healing, and return to full and unlimited function with minimal risk of complications. Injury severity determines the ease with which this goal is attained and the most appropriate method of treatment. For extension-type supracondylar fractures, Gartland’s radiographic classification system is a helpful guide to injury severity and optimal treatment.

Because type I fractures are truly nondisplaced, there is minimal swelling and no significant risk of neurovascular injury. Immediate application of an above-elbow cast with the elbow at 90 degrees of flexion (and neutral angles of pronation and supination) is safe and is all that is necessary to prevent loss of reduction and to provide pain relief. If future swelling is a concern, the cast may be bivalved, splitting all fiberglass or plaster elements down to—but not through—the cast padding. The two halves of the cast are spread apart to accommodate swelling and held together with three or four circumferential bands of tape. Five to 10 days later, the cast is simply overwrapped with fiberglass. After 3 weeks of immobilization, the cast is removed and elbow rangeof-motion exercises are begun. At 6 weeks, the fracture is essentially healed and the patient may resume full activity.

TYPE II FRACTURES Despite an intact osseous hinge, type II fractures can vary significantly in displacement and injury severity, which determines treatment choice. For fractures in which the anterior humeral line does intersect the capitellum, reduction may not be necessary and immediate cast immobilization in 90 degrees of flexion is appropriate. Closed reduction should be seriously considered for moderately displaced fractures when the anterior humeral line passes anterior to the capitellum. In a cooperative reliable patient with minimal elbow swelling, gentle closed reduction may be performed under regional anesthesia or conscious sedation in the emergency department, and the fracture should be immobilized in an above-elbow cast with enough flexion to maintain fracture reduction (see Fig. 14-6). If any swelling is present, close attention to the neurovascular examination is critical when immobilizing the elbow in more than 100 degrees of flexion. Fluoroscopic observation can be helpful in determining the minimum degree of flexion required to safely maintain fracture reduction. Displaced or angulated type II fractures may be associated with neurovascular injury. Neurologic and vascular examinations, performed and documented meticulously, are essential. Swelling may make it impossible or unsafe to flex the elbow enough so that the fracture reduction can be maintained. In such situations, closed reduction and percutaneous pinning is indicated to maintain fracture reduction without compromising the neurovascular integrity of the limb. Moderately or severely angulated type II fractures may also be associated with medial column impaction, lateral column impaction, or rotation. If unrecognized, any of these

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three variations of a type II fracture can lead to malunion and angular deformity. Medial impaction, lateral impaction, and rotation all necessitate closed reduction, which is most dependably maintained with percutaneous pinning.19 After percutaneous pinning, a splint or bivalved cast is applied, and 5 to 10 days later, the bivalved cast is overwrapped or the splint removed and an above-elbow cast applied.

TYPE III FRACTURES Completely displaced supracondylar humerus fractures are intrinsically unstable, typically cause severe swelling, and are frequently associated with neurovascular injury (Fig. 14-11). These factors make management of type III fractures challenging and anxiety provoking.

CLOSED REDUCTION Type III extension-type fractures have an intact posterior periosteal hinge, which, in addition to the triceps tendon, provides some stability to the fracture when it is immobilized in flexion. Paradoxically, the completely displaced supracondylar fracture is just the fracture that requires elbow flexion greater than 100 degrees to maintain adequate fracture reduction, but it is also the fracture least able to tolerate flexion beyond 100 degrees because of swelling and risk of neurovascular compromise (Fig. 14-12).53 Because of the relatively high incidence of malunion and neurovascular compromise, immobilization in flexion has been replaced by closed or open reduction and pinning.47,59,64,87,89

PERCUTANEOUS PINNING In 1988, Pirone et al64 published a series of 230 displaced supracondylar humerus fractures and analyzed the results of (1) closed reduction and percutaneous pinning, (2) open reduction, (3) skeletal traction, and (4) closed reduction with casting. Pirone and colleagues reported significantly better results in the group treated with closed reduction and percutaneous pinning as compared with the other three groups. Subsequent studies have confirmed these results, and closed reduction with percutaneous pinning has become the most used and most accepted treatment.12,27,35,36,87 In the emergency department, a meticulous neurovascular examination should be performed and properly documented including median, radial, ulnar, and anterior interosseous nerve function. Because it has only motor function, anterior interosseous nerve injury has been underdiagnosed in the past, but separate investigators have provided substantial evidence to suggest that the anterior interosseous nerve is the nerve most fre-

quently injured in association with supracondylar fractures.17,18,21 Because of the severe nature of the injury, the amount of manipulation required for reduction, and the possible need to perform an open reduction, an attempt at closed reduction should not be made in the emergency department. However, severe displacement and deformity may result in a pulseless or dysvascular extremity. In this situation, under adequate analgesia in the emergency department, gently correcting the severe deformity followed by splinting in a relaxed position— usually approximately 30 degrees of elbow flexion—often restores the radial pulse and minimizes further tissue damage caused by severe fracture displacement. If the limb remains dysvascular, emergent transport to the operating room is indicated, where closed reduction restores perfusion to the upper extremity in the vast majority of patients. A question that has generated considerable discussion in recent medical literature concerns whether a neurovascularly intact, displaced, type III fracture should be treated emergently in the middle of the night, or whether such a fracture can be effectively and safely treated the following morning? In a review of 198 patients with a displaced type III fracture and perfused limb, Mehlman et al55 compared urgent treatment with treatment provided the day following injury and reported no statistical difference between groups with regard to perioperative complications or the need to convert to open fracture reduction. Additional authors have published similar results, suggesting that compared with emergent treatment, delay until the following day does not increase the risk of perioperative complication or the need for open reduction, and does not compromise final outcome.37,43 One article did note an increased need to convert to open reduction when treatment was delayed.85 Our opinion is that the fracture is never easier to reduce than the moment after the fracture occurs; each subsequent hour adds to the swelling and difficulty of reduction. However, there does not seem to be any significant difference in clinical outcome between a neurovascularly intact extremity with a fracture that is reduced and pinned at 2:00 AM compared with a fracture in which treatment is delayed until later that same morning. Closed reduction and percutaneous pinning can be performed successfully using a variety of techniques with the patient positioned supine, lateral, or prone.28 We prefer to perform the reduction with the patient positioned supine using the following series of steps. After general anesthesia has been administered, the patient is positioned toward the edge of the operating table with the affected extremity carefully supported over the side. C-arm fluoroscopy is brought in from the foot of the table, parallel to the table, so the patient’s arm can rest on the C-arm.

Chapter 14 Supracondylar Fractures of the Elbow in Children

FIGURE 14-11 A, Five-year-old patient with a markedly displaced supracondylar fracture whose neurovascular supply was intact. B, After closed reduction and pinning, the radial pulse and median nerve function were lost. C, Entrapment of the brachial artery and median nerve necessitated opening of the fracture site and repinning. Intraoperative angiography shows spasm of the brachial artery that resolved.

215

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FIGURE 14-12

Injection of a cadaver arm from an adolescent shows kinking of vessels. A, Vascular relationships at 90 degrees of flexion. B, In extension, the artery may be traumatized by the proximal fragment or kinked by soft tissue attachments. C, In hyperflexion, the vessels may be compressed in the edematous antecubital region. (From Ogden, J. A.: Skeletal Injury in the Child. Philadephia, Lea & Febiger, 1982.)

Before prepping, with the arm less constrained by drapes, closed reduction is attempted. If the metaphyseal spike from the proximal fragment is tenting the skin and subcutaneous tissue, the brachialis is gently “milked” off of the fragment.5 With the arm in a relaxed position at approximately 20 to 30 degrees of elbow flexion, the medial-lateral displacement is corrected. When available, an assistant supports the forearm, and the operating surgeon places a thumb on posterior aspect of the medial and lateral columns of the distal humeral fragment. The final reduction maneuver involves the assistant’s applying gentle longitudinal traction while the operating surgeon uses each thumb to manipulate the distal fragment distally and anteriorly. Simultaneously, the assistant flexes the elbow to maintain the reduction (Fig. 14-13).58 When working alone, the operating surgeon can apply traction to the forearm and flexion to the elbow with one hand while applying distal and anterior pressure to the patient’s olecranon with the other hand (Fig. 14-14). If the initial displacement is posterior and medial, suggesting an intact medial periosteal hinge, the forearm is pronated. If the initial displacement is posterior and lateral, the forearm is supinated. Occasionally, pronation can cause displacement when in theory it should improve the reduction and vice versa with supination. The key is remaining flexible and gently trying several methods until the best and most stable reduction is obtained. The reduction is imaged with fluoroscopy on anteroposterior and lateral views. If the reduction is adequate or if it is clear that an adequate reduction is attainable with a second attempt, the elbow is extended to approximately 20 degrees of flexion, prepared, and draped. We

prepare the hand into the field to allow neurovascular monitoring and prep to the shoulder to allow for the use of a sterile tourniquet if necessary. After draping, the reduction maneuver is repeated, adequate alignment is confirmed fluoroscopically, and the elbow is temporarily held in a hyperflexed position to maintain the reduction. Controversy persists about the optimal pin configuration that maintains adequate fracture reduction and minimizes potential complications.32,34,48,74 Crossed pins provide the greatest biomechanical stability but have the potential to cause ulnar nerve injury90 (Fig. 14-15). Published reports suggest that the biomechanical stability sacrificed by using two or three lateral pins is not clinically significant and avoids iatrogenic ulnar nerve injury.15,82 If two lateral pins are used, great care must be taken to ensure that both pins cross through both fracture fragments with adequate spacing between the pins; otherwise, fracture reduction may be lost. To pin the medial column first, the elbow is externally rotated; to pin the lateral column, internal rotation is used. Sometimes the fracture is more stable in internal or in external rotation, and this determines which column is pinned first. Because internal rotation of the elbow can result in posterior displacement of the medial distal fragment causing varus angulation, when possible, we typically externally rotate the elbow and pin the medial column first.63 The operating surgeon palpates the medial epicondyle and uses a thumb to retract and protect the ulnar nerve posteriorly (see Fig. 14-13). A 0.062 Kirschner wire is then placed just anterior to the thumb on the medial epicondyle. The Kirschner wire is angled cephalad to

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FIGURE 14-13 Closed reduction of type III supracondylar humeral fracture. A, C-arm fluoroscopy is brought in from the foot of the operating table and used as the operating surface. B, Before surgical preparation and draping, and after medial-lateral displacement is corrected, the fracture is reduced. The operating surgeon places a thumb on the medial and lateral columns translating the fragment distally and anteriorly while the assistant flexes the elbow. C, After ensuring that a closed reduction can be obtained, the surgeon repeats the reduction maneuver after the arm has been prepared and draped. D, The operating surgeon retracts and protects the ulnar nerve with a thumb while placing the medial pin.

travel within the medial column of bone and advanced until it just penetrates the opposite cortex. Using fluoroscopy, the position of the Kirschner wire is checked in anteroposterior and lateral planes. This first pin often substantially improves fracture stability, allowing extension past 90 degrees to image the elbow and facilitate placement of the second pin. The second pin is placed within the lateral column of bone, crossing the first pin well above the fracture site (see Fig. 14-15). The pins are left protruding through the skin, bent at a 90-degree angle, cut long, and a foam or gauze dressing placed beneath the ends to ensure that the pins will not become buried beneath the skin while in the postoperative dress-

ing. Literature describing the use of bioabsorbable pins has reported an unacceptable level of implant failure and loss of reduction.11 Occasionally, the elbow is too swollen or the child too young to allow accurate palpation of the medial epicondyle. In such instances there are several options. A 1-cm incision may be made directly over the medial epicondyle. Soft tissues are spread with a small clamp down to the medial condyle, and a small retractor is used to hold the ulnar nerve and all soft tissues posterior to the pin. With the ulnar nerve retracted, the medial column pin can be placed safely. Alternatively, two or three lateral pins may be used. Zionts’ cadaver study90

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FIGURE 14-14 A, Manipulative reduction is performed by exerting gentle traction in extension and supination. B, Direct pressure is exerted to realign the distal fragment. C, After realignment, the elbow is flexed to 120 degrees and appropriately pronated or supinated. D, Medial displacement of the distal fragment often requires pronation for stability, with the elbow flexed.

Chapter 14 Supracondylar Fractures of the Elbow in Children

FIGURE 14-14, cont’d

E, Lateral displacement of the distal fragment frequently requires supination for stability, with the elbow flexed. (From Micheli, L. J., Skolnick, D., and Hall, J. E.: Supracondylar fractures of the humerus in children. Am. Family Physician 19:100, 1979.)

demonstrated that, after crossed pins, the next strongest configuration used three lateral pins; two pins placed obliquely across the fracture from the distal lateral to the proximal medial aspect and a third through the capitellum directed up the humeral shaft.

OPEN REDUCTION Inability to achieve closed reduction is usually due to soft tissue interposition. Most frequently, the brachialis muscle is interposed and can be “milked” off the distal metaphyseal spike by closed means. Occasionally, the brachial artery, median nerve, or radial nerve can become interposed between the fracture fragments. Inability to achieve an adequate closed reduction warrants open reduction. Fractures displaced posterolaterally are most likely to cause interposition of the median

219

nerve or brachial artery and are approached anteromedially. Conversely, fractures displaced posteromedially are more likely to have interposition of the radial nerve and are approached anterolaterally. Several recent papers have reported excellent success using a small transverse incision in the elbow flexion crease.7,46,80 Through this limited approach, the offending interposed tissue can usually be easily extracted from the fracture site and anatomic reduction confirmed before percutaneous pinning proceeds. Past reluctance to perform open reduction of supracondylar fractures for fear of causing elbow stiffness has been shown to be unfounded: Several studies have demonstrated that open reduction is safe and effective and does not increase the risk of elbow stiffness.4,6,14,30,73 The majority of severely displaced supracondylar fractures without a radial pulse regain the pulse after fracture reduction. If after closed reduction, the radial pulse does not return and the limb is not perfused, immediate exploration of the brachial artery and open reduction is indicated. A more controversial situation is encountered when an adequate reduction is obtained, the limb remains pulseless, and the state of limb perfusion is unclear. In separate reports, Schoenecker and Shaw and their respective associates have formulated similar algorithms that are useful in this situation.71,72 After reduction and pinning, the vascular status of the limb is assessed. If the radial pulse is detectable by Doppler ultrasound and the hand is pink with brisk capillary refill, the elbow is immobilized, the case is completed, and the patient is carefully monitored overnight. If the radial pulse is not detectable by ultrasound, the brachial artery is explored at the fracture site. Using this algorithm, combining numbers from both studies, 10 patients did not have a detectable radial pulse by Doppler ultrasound and were explored immediately. All 10 arteries were found to be obstructed or transected, and in all extremities, blood flow was re-established by freeing the trapped or kinked vessel (five extremities) or by repairing the lesion with vein graft (five extremities). Using Doppler ultrasound to detect a radial pulse appears to be effective at detecting almost all clinically significant vascular injuries without arteriography and with minimal risk of exposing patients to unnecessary vascular exploration.

POSTOPERATIVE CARE After the fracture is reduced and pinned and adequate perfusion of the limb confirmed, the upper extremity is immobilized. Pin stabilization permits immobilization in a position that optimizes perfusion and minimizes swelling. A simple posterior splint or bivalved cast may be used to immobilize the elbow in approximately 80

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FIGURE 14-15 A, Closed reduction and percutaneous pinning was performed for a markedly displaced type III supracondylar humerus fracture. B, Pins cross well above the fracture site, maintaining excellent alignment at the time of pin removal 3 weeks postoperatively.

degrees of flexion. A fluffed 4-by-4-inch gauze may be placed in the antecubital fossa as great care is taken to prevent constriction from the dressing. A neurologic examination is performed immediately after the patient awakens from anesthesia, and median, radial, and ulnar nerve function is assessed. Patients are admitted overnight for neurovascular monitoring. The elbow is elevated, and ice is applied through the dressing. Most patients are discharged from the hospital on the day after surgery and are seen back in follow-up 5 to 10 days after surgery. At that time, radiographs are taken and the limb is examined. If adequate reduction has been maintained and swelling has decreased, bivalved casts are overwrapped with fiberglass casting material or the posterior splint may be removed and a cast applied. Three weeks after the injury, the cast is removed and radiographs are repeated. If periosteal bone formation across the fracture is present, the pins are removed, immobilization is discontinued, and gentle active range-of-motion exercise is begun. Immobilization longer than 4 weeks increases the risk of permanent elbow stiffness. Vuckov84 reported immobilizing patients for as short as 2 weeks following supracondylar fractures with no untoward consequences.

TRACTION Historically, traction has been used with acceptable results to obtain and maintain supracondylar fracture reduction until healing has progressed enough to permit cast immobilization.* More recently, improved results, *See references 2,9,20,22,23,42,44,47,70,77,78,83.

decreased cost, and decreased time in the hospital after closed reduction and percutaneous pinning have resulted in complete abandonment of traction for supracondylar fracture treatment.29,64,67,81 Rarely, however, traction may be an appropriate treatment for type III supracondylar fractures. The most common indication for traction would be a displaced fracture that presents for treatment longer than 24 hours after injury and with severe swelling that precludes open or closed reduction (Fig. 14-16). Additional indications for traction include patients with a contraindication to general anesthesia or lack of access to adequate imaging or other equipment necessary for pinning. Two forms of traction traditionally have been used: cutaneous or Dunlop’s traction and skeletal traction. Dunlop’s traction is applied in a lateral direction with the patient lying supine. Pronation and supination of the forearm and varus or valgus tilt of the distal fragment are difficult to control and correct with this method of traction. The forearm tends to rotate into supination, resulting in a loss of stability that ordinarily is achieved when the forearm is maintained in the pronated position in most common fractures. This position also places the distal fracture fragment in some extension. Because of these disadvantages, if traction is necessary we prefer to use skeletal traction with the arm held overhead. Under general or regional anesthesia, a Kirschner wire may be inserted through the proximal ulna at the olecranon. An olecranon screw, which is inserted at the same level, is easier to insert and avoids risk to the ulnar nerve. Gross displacement is corrected at this time. The arm is suspended from an overhead frame with a sling under

Chapter 14 Supracondylar Fractures of the Elbow in Children

221

FIGURE 14-16 A to C, A 9-year-old patient with a displaced supracondylar fracture presented with severe swelling and fracture blisters that precluded closed reduction and percutaneous pinning. D, Overhead skeletal traction is used to safely obtain and maintain adequate fracture alignment.

the forearm to control its position. Three to five pounds of traction is usually sufficient to reduce and stabilize the fracture. Too much weight elevates the shoulder and twists the thorax causing the child to shift position resulting in loss of control of the fracture fragment. Suspension of the forearm in this position permits rapid reduction of edema and good control of elbow flexion. Rotational deformity can be controlled by placing the arm in either a cephalad or a caudad position. If neces-

sary, a lateral sling around the upper arm also may provide lateral traction to correct anterior displacement of the proximal fragment (Fig. 14-17). Serial radiographs must be taken, and producing adequate films may require some ingenuity on the part of the technician and direction on the part of the physician. The lateral projection usually is obtained without difficulty, but the axial view requires overcoming the obstruction of the overhead frame by some means. Fracture stability is assessed

FIGURE 14-16, cont’d

E and F, Six months after injury, the fracture is completely healed and the

outcome excellent.

FIGURE 14-17

A, Position of patient in bed relative to overhead traction. B, Angulation of the traction controls reduction. (From Ogden, J. A.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1982.)

Chapter 14 Supracondylar Fractures of the Elbow in Children

clinically and radiographically. When the fracture is minimally tender to palpation, swelling has subsided and early callus has developed, a well-molded aboveelbow cast is applied.

COMPLICATIONS Complications are discussed in detail in Chapter 15. The two broad categories of complications most often associated with supracondylar humerus fractures are malunion and neurovascular injury. Even the most skilled surgeons occasionally encounter complications, but adherence to the principles outlined here will help to minimize these unfortunate events.

Acknowledgment The author would like to acknowledge Dr. Rudolph Klassen for his contributions to this chapter. The information presented in this chapter is based on his efforts in previous editions.

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29. France, J., and Strong, M.: Deformity and function in supracondylar fractures of the humerus in children variously treated by closed reduction and splinting, traction, and percutaneous pinning. J. Pediatr. Orthop. 12:494, 1992. 30. Furrer, M., Mark, G., and Ruedi, T.: Management of displaced supracondylar fractures of the humerus in children. Injury 22:259, 1991. 31. Gartland, J. J.: Management of supracondylar fractures of the humerus in children. Surg. Gynecol. Obstet. 109:145, 1959. 32. Gordon, J. E., Patton, C. M., Luhmann, S. J., Bassett, G. S., and Schoenecker, P. L.: Fracture stability after pinning of displaced supracondylar distal humerus fractures in children. J. Pediatr. Orthop. 21:313, 2001. 33. Graham, H. A.: Supracondylar fractures of the elbow of children. Part II. Clin. Orthop. 54:93, 1967. 34. Green, D. W., Widmann, R. F., Frank, J. S., and Gardner, M. J.: Low incidence of ulnar nerve injury with crossed pin placement for pediatric supracondylar humerus fractures using a mini-open technique. J. Orthop. Trauma 19:158, 2005. 35. Green, N. E.: Fractures and dislocations about the elbow. In Green, N. E., and Swiontkowski, M. F. (eds.): Skeletal Trauma in Children. Philadelphia, W. B. Saunders Co., 1994, p. 223. 36. Grimard, G., Labelle, H., and Girard, P.: Treatment of displaced supracondylar fractures of the distal humerus in children: a prospective and controlled study. Poster Exhibit, American Orthop Assoc, Annual Meeting, 1992. 37. Gupta, N., Kay, R. M., Leitch, K., Femino, J. D., Tolo, V. T., and Skaggs, D. L.: Effect of surgical delay on perioperative complications and the need for open reduction in supracondylar humerus fractures in children. J. Pediatr. Orthop. 24:245, 2004. 38. Hagen, R.: Skin traction treatment of supracondylar fractures of the humerus in children. Acta Orthop. Scand. 35:138, 1964. 39. Hanlon, C. R., and Estes, W. L.: Fractures in childhood: a statistical analysis. Am. J. Surg. 87:312, 1954. 40. Henrikson, B.: Supracondylar fractures of the humerus in children. Acta Chir. Scand. 369(suppl.):1, 1966. 41. Holmberg, L.: Fractures in the distal end of the humerus in children. Acta Orthop. Scand. 92(suppl.):103, 1945. 42. Hoyer, A.: Treatment of supracondylar fractures of the humerus by skeletal traction in an abduction splint. J. Bone Joint Surg. 34A:623, 1952. 43. Iyengar, S. R., Hoffinger, S. A., and Townsend, D. R.: Early versus delayed reduction and pinning of type III displaced supracondylar fractures of the humerus in children: a comparative study. J. Orthop. Trauma 13:51, 1999. 44. Jefferiss, C. D.: “Straight lateral traction” in selected supracondylar fractures of the humerus in children. Injury 8:213, 1977. 45. Khare, G. N., Gautam, V. K., Kochlar, V. L., and Anand, C.: Prevention of cubitus varus deformity in supracondylar fractures of the humerus. Injury 22:202, 1991. 46. Koudstaal, M. J., De Ridder, V. A., De Lange, S., and Ulrich C.: Pediatric supracondylar humerus fractures: the anterior approach. J. Orthop. Trauma 16:409, 2002.

47. Kurer, M. H. J., and Regan, M. W.: Completely displaced supracondylar fracture of the humerus in children. A review of 1708 comparable cases. Clin. Orthop. 256:205, 1990. 48. Lee, S. S., Mahar, A. T., Miesen, D., and Newton, P. O.: Displaced pediatric supracondylar humerus fractures: biomechanical analysis of percutaneous pinning techniques. J. Pediatr. Orthop. 22:440, 2002. 49. Leitch, K. K.. Kay, R. M., Femino, J. D., Tolo, V. T., Storer, S. K., and Skaggs, D. L.: Treatment of multidirectionally unstable supracondylar humeral fractures in children. A modified Gartland type—IV fracture. J. Bone Joint Surg. 88A:980, 2006. 50. Lipscomb, P.: Vascular and neural complications in supracondylar fractures of the humerus in children. J. Bone Joint Surg. 37A:487, 1955. 51. Lund-Kristensen, J., and Vibild, O.: Supracondylar fractures of the humerus in children. Acta Orthop. Scand. 47:375, 1976. 52. MacLemman, A.: Common fractures about the elbow in children. Surg. Gynecol. Obstet. 64:447, 1947. 53. Mapes, R. C., and Hennrikus, W. L.: The effect of elbow position on the radial pulse measured by Doppler ultrasonography after surgical treatment of supracondylar elbow fractures in children. J. Pediatr. Orthop. 18:441, 1998. 54. Maylahn, D. J., and Fahey, J. J.: Fractures of the elbow in children. Review of three hundred consecutive cases. J. A. M. A. 166:220, 1958. 55. Mehlman, C. T., Strub, W. M., Roy, D. R., Wall, E. J., and Crawford, A. H.: The effect of surgical timing on the perioperative complications of supracondylar humeral fractures in children. J. Bone Joint Surg. 83A:323, 2001. 56. Micheli, L. J., Santore, R., and Stanitski, C. L.: Epiphyseal fractures of the elbow in children. Am. Family Physician 22:107, 1980. 57. Micheli, L. J., Skolnick, D., and Hall, J. E.: Supracondylar fractures in the humerus in children. Am. Family Physician 19:100, 1979. 58. Minkowitz, B., and Busch, M. T.: Supracondylar humerus fractures. Current trends and controversies. Orthop. Clin. North Am. 25:581-594, 1994. 59. Mohammed, S., and Rymaszewski, L. A.: Supracondylar fractures of the distal humerus in children. Injury 26:487, 1995. 60. Nassar, A.: Correction of varus deformity following supracondylar fracture of the humerus. Poster Presentation, American Orthopedic Assoc., Annual Meeting, 1992. 61. Ogden, J.: Skeletal Injury in the Child. Philadelphia, Lea & Febiger, 1982, p. 240. 62. Ottolenghi, C. E.: Prophylactic due Syndrome de Volkmann dans des Humerus Supracondyliennes du Coude chez l’enfant. Rev. Chir. Orthop. 57:517, 1971. 63. Paradis, G., Lavallee, P., Gagnon, N., and Lemire, L.: Supracondylar fractures of the humerus in children. Technique and results of crossed percutaneous K-wire fixation. Clin. Orthop. 297:231-237, 1993. 64. Pirone, A. M., Graham, H. K., and Krajbich, J. I.: Management of displaced extension-type supracondylar fractures

Chapter 14 Supracondylar Fractures of the Elbow in Children

65.

66. 67.

68.

69.

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73.

74.

75. 76. 77. 78.

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79. Strait, R. T., Siegel, R. M., and Shapiro, R. A.: Humeral fractures without obvious etiologies in children less than 3 years of age: when is it abuse? Pediatrics 96 (4 pt 1):667671, 1995. 80. Suh, S. W., Oh, C. W., Shingade, V. U., Swapnil, M. K., Park, B. C., Lee, S. H., and Song, H. R.: Minimally invasive surgical techniques for irreducible supracondylar fractures of the humerus in children. Acta Orthop. 76:862, 2005. 81. Sutton, W. R., Green, W. B., Georgopoulos, G., and Dameron, T. B., Jr.: Displaced supracondylar humeral fractures in children. A comparison of results and costs in patients treated by skeletal traction versus percutaneous pinning. Clin. Orthop. 278:81, 1992. 82. Topping, R. E., Blanco, J. S., and Davis, T. J.: Clinical evaluation of crossed-pin versus lateral-pin fixation in displaced supracondylar humerus fractures. J. Pediatr. Orthop. 15:435, 1995. 83. Vahvanen, V., and Aalto, K.: Supracondylar fractures of the humerus in children. A long-term follow-up study of 107 cases. Acta Orthop. Scand. 49:225, 1978. 84. Vuckov, S., Kvesi, A., Rebac, Z., Cuculi, D., Lovasi, F., and Bukvi, N.: Treatment of supracondylar humerus fractures in children: minimal possible duration of immobilization. Coll. Antropol. 25:255, 2001. 85. Walmsley, P. J., Kelly, M. B., Robb, J. E., Annan, I. H., and Porter, D. E.: Delay increases the need for open reduction of type-III supracondylar fractures of the humerus. J. Bone Joint Surg. 88B:528, 2006. 86. Wilkins, K. E.: Residuals of elbow trauma in children. Orthop. Clin. North Am. 21:291, 1990. 87. Wilkins, K. E.: Supracondylar fractures: what’s new? J. Pediatr. Orthop. 6:110, 1997. 88. Williamson, D. M., Coates, C. J., Miller, R. K., and Cole, W. G.: Normal characteristics of the Baumann (humerocapitellar) angle: an aid in assessment of supracondylar fractures. J. Pediatr. Orthop. 12:636, 1992. 89. Williamson, D. M., and Cole, W. G.: Treatment of selected extension supracondylar fractures of the humerus by manipulation and strapping in flexion. Injury 24:249, 1993. 90. Zionts, L. E., McKellop, H. A., and Hathaway, R.: Torsional strength of pin configurations used to fix supracondylar fractures of the humerus in children. J. Bone Joint Surg. 76A:253-256, 1994.

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CHAPTER

15

Complications of Supracondylar Fractures of the Elbow Amy L. McIntosh and Scott J. Mubarak

INTRODUCTION Complications associated with supracondylar humerus fractures can be divided into broad categories. The etiology of a complication may be due to the injury itself or the management of the injury. The complication may be associated with the soft tissues, such as a neurovascular problem (acute), or in the osseous structures, such as malalignment (chronic). In this chapter, we first discuss the anatomy of this area, then neurovascular problems, and finally bony complications of supracondylar humerus fractures in children.

NEUROVASCULAR PROBLEMS ASSOCIATED WITH SUPRACONDYLAR FRACTURES ANATOMY Anterior to the supracondylar area of the distal humerus is the median nerve (Fig. 15-1). In the proximal forearm, the anterior interosseous branch separates to innervate the flexor profundus to the index finger and the flexor pollicis longus and then terminates with the innervation of the pronator quadratus. There is no sensory branch for this nerve. The remainder of the median nerve traverses the forearm and supplies the sensation to the palmar aspect of the thumb, the index finger, the long finger, and the radial aspect of the ring finger. The radial nerve lies posterolateral to the usual location of supracondylar fractures and, thus, is less commonly involved (see Fig. 15-1). The ulnar nerve with its posterior location is uncommonly involved with a typical extension-type supracondylar fracture. The forearm consists of two basic compartments: volar and dorsal (Fig. 15-2). The volar compartment includes the flexors and pronators of the forearm and wrist, which may be further divided into superficial and

deep muscle groups. The superficial muscles include the flexor carpi ulnaris, the palmaris longus, the flexor carpi radialis, and the pronator teres. The deeper group of muscles consists of the flexor digitorum superficialis and profundus, the flexor pollicis longus, and the pronator quadratus. The median and ulnar nerves traverse the forearm between the superficial and deep flexor groups. The major arteries about the elbow include the brachial artery, which bifurcates in the region of the radial head to form the radial and ulnar arteries. The dorsal compartment consists mainly of the wrist and finger extensors. The mobile wad of Henry includes the brachioradialis and the extensor carpi radialis longus and the brevis muscles. This group of muscles is physically and functionally distinct; it lies between the dorsal and volar forearm compartments and probably should be considered a separate compartment. The major nerve of the dorsal compartment is the posterior interosseous nerve, a continuation of the radial nerve. The major artery of the dorsal compartment is the posterior interosseous artery.

ETIOLOGY: NERVE INJURY Most nerve injuries are associated with type III displaced supracondylar fractures. In a recent study by Louahem et al,46 the most commonly injured nerve was the anterior interosseous branch of the median nerve. This is likely due to its anatomic arrangement of the exclusively motor posterior fascicles which are exposed to the zone of injury, and its tight tethering to the proximal forearm musculature. The second-most commonly involved nerve was the ulnar, followed by the radial nerve. Ulnar nerve injury was most commonly associated with posterolateral fracture patterns due to direct contusion and stretching of the nerve from the medially displaced proximal humeral fragment or edema within the cubital tunnel. Radial nerve injury was consistently associated with posteromedial fractures due to contusion and stretching from the laterally displaced proximal humeral fragment. Ulnar nerve injury also occurred iatrogenically in 5% of patients during medial percutaneous pin placement in a recent large series.69 The causes of iatrogenic ulnar nerve injury include (1) direct penetration of the nerve or its sheath by the medial pin; (2) constriction of the cubital tunnel by the pin while the elbow is in flexion; (3) medial pin injury to an unstable ulnar nerve, which subluxates or dislocates anteriorly when the elbow is in flexion; and (4) nerve contusion and edema.63 In 2001, Skaggs et al reported on 345 extension-type supracondylar humerus fractures in children treated with closed reduction and percutaneous pin fixation. The use of a medial pin was associated with an iatrogenic ulnar

Chapter 15 Complications of Supracondylar Fractures of the Elbow

COMPARTMENT STRUCTURES OF UPPER ARM Radial artery and nerve Triceps muscle Brachialis muscle

Biceps muscle Humerus

Radial nerve Cephalic vein

Ulnar nerve Basilic vein Brachial artery

Median nerve

227

TREATMENT After reduction of the fracture and stabilization with percutaneous pinning, re-evaluation of the neurovascular examination is mandatory. On rare occasions, the compromised nerve may recover before the patient’s discharge, but in most incidents, the neurapraxia requires observation and will gradually return over the ensuing months. If after 4 to 6 months, no return of function is noted, electromyelographic and nerve conduction studies to evaluate the status of recovery are recommended. Only rarely have cases been reported of permanent nerve deficits requiring later neurolysis, grafting, or tendon transfer. Nearly all nerves will return to normal function within the first 6 months following the injury.19 Advances in surgical techniques with lateral pin entry fixation have demonstrated significant decreases in iatrogenic ulnar nerve injury and satisfactory mechanical stability in Gartland type II, III and IV fractures.43,69,70 Authors recommend two-pin lateral-entry fixation as the primary mode of percutaneous fixation in all unstable supracondylar humerus fractures with the addition of a third lateral-entry pin or medial pin as needed to achieve fracture stability.

ISCHEMIC INJURIES FIGURE 15-1

Major neurovascular structures of the elbow. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981, p. 24.)

nerve injury in 15% of patients in which the pin was placed with the elbow positioned in hyperflexion. Only 4% of patients sustained nerve injury when the medial pin was placed without hyperflexion, and no iatrogenic injuries occurred in patients treated with all lateral entry pin fixation.69 A displaced supracondylar fracture presenting with an absent radial pulse has a 50% to 60% incidence of associated nerve injury at fracture presentation.19

CLINICAL DIAGNOSIS The diagnosis of anterior interosseous nerve injury is easily missed. The inability to flex the distal segment of the thumb and the index fingers is an indication of this nerve being damaged. With a pure anterior interosseous nerve injury, there is no sensory deficit. Sensory examination by light touch and two-point discrimination is recommended for children, especially in the autonomous zones of the median, ulnar, and radial nerve.

Two basic pathologic processes may result from supracondylar fractures or other injuries to the elbow region that can lead to forearm ischemia: (1) arterial injury and (2) compartment syndrome from hemorrhage or postischemic swelling (Fig. 15-3). An arterial injury may result from laceration, thrombus, embolus, intimal tear, or pseudoaneurysm (Fig. 15-4). Such an injury may cause nerve and muscle ischemia directly or may result in postischemic swelling or hemorrhage, thereby causing a compartment syndrome. The muscles of the extremities are grouped into compartments that are enclosed by a relatively noncompliant osteofascial envelope. Muscle swelling causes increased pressure within the compartment that is not easily dissipated owing to the relatively inelastic nature of the surrounding fascia. If the pressure remains sufficiently high for several hours, loss of function of intracompartmental nerves and muscles due to ischemia may result. A compartment syndrome is a condition in which the high pressure within the compartment compromises the circulation to the nerves and the muscles within the involved compartment. In either event, nerve and muscle ischemia may result, possibly leading to a forearm contracture. To prevent permanent loss of nerve and muscle function, this condition must be diagnosed promptly and

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Part IV Conditions Affecting the Child’s Elbow

Ulna

Extensor carpi ulnaris m. Radius Supinator m. Extensor digitorum m. Extensor carpi radialis brevis m.

Brachial v. Ulnar n.

Extensor carpi radialis longus m.

Flexor carpi radialis and palmaris longus and flexor digitorum superficialis m. bundle Medial n.

Radial n. (prof.) Radial n. (superf.) Radial v. Medial cubital v.

Ulnar a. Ulnar v.

Posterior interosseous a., v., n.

Flexor digitorum profundus m. Palmaris Flexor carpi longus m. ulnaris m. Ulnar a., v., n.

Extensor carpi ulnaris m. Extensor digitorum m. Extensor digitorum (comm.) m. Extensor carpi radialis brevis and longus m. Pronator teres m. Brachioradialis m. Radial a., v., n. Brachialcephalic v. Flexor pollicis longus m. Flexor carpi radialis m. Median a., v., n.

Extensor carpi radialis longus and brevis m.

Extensor carpi ulnaris m.

Antebrachial cephalic v. Pronator quadratus m. Radial a., v., n. Flexor carpi radialis m.

Flexor carpi ulnaris m. Ulnar n. Ulnar a.

Median n.

treated correctly. Volkmann’s contracture is the popular term that refers to the end stage of an ischemic injury to the muscles and nerves of the limb (Fig. 15-5). Untreated compartment syndromes and arterial injuries are the primary causes of Volkmann’s contracture. The term Volkmann’s ischemia is nonspecific and should not be used.

ETIOLOGY: ISCHEMIA In general, the most common traumatic event that produces a compartment syndrome or an arterial injury about the elbow is the supracondylar fracture of the distal humerus (Fig. 15-6). In 1956, Lipscomb noted that supracondylar fractures were the cause of 48% of Volkmann’s contractures in 92 cases from the Mayo Clinic.45 In 1967, Ehrlich and Lipscomb, in a review of 32 more

FIGURE 15-2

Forearm compartments: transverse sections through the left forearm at various levels. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981, p. 28.)

cases of Volkmann’s contracture, reported that 34% were due to supracondylar fractures and 22% were due to forearm fractures.13 In 1979, Mubarak and Carroll, reporting on 58 Volkmann’s contractures in children (Fig. 15-7), found that supracondylar fractures had caused only 16% of these contractures.56 In most recent studies, compartment syndromes are extremely unusual because of the advent of early closed reduction and percutaneous pinning. An arterial injury can produce nerve and muscle ischemia directly or the additional problem of a compartment syndrome by one of two mechanisms (see Fig. 15-3).57 First, if the major vessel is lacerated, hemorrhage into the compartment may produce the syndrome. Second, a compartment syndrome may result from postischemic swelling if there is inadequate collateral circulation or if the vessel is only partially

Chapter 15 Complications of Supracondylar Fractures of the Elbow

TRAUMA Supracondylar fracture

Post-traumatic swelling Hemorrhage Arterial injury

Increased tissue pressure

229

occluded, for example, from an arterial spasm or an intimal tear. In this situation, the decreased perfusion and ischemia of both capillaries and muscles will cause an increase in the permeability of the capillary walls. The resulting edema will then cause more ischemia, and a vicious circle may ensue. When there is complete arterial occlusion, a compartment syndrome may develop from postischemic swelling or reperfusion injury after the circulation is restored (Fig. 15-8). When complete arterial occlusion is secondary to massive emboli or prolonged use of a tourniquet in which the circulation is not restored, gangrene rather than compartment syndrome will likely result.

Post-ischemic swelling

CLINICAL DIAGNOSIS Compartment syndrome

Nerve and muscle infarction

Volkmann’s contracture

FIGURE 15-3

Diagrammatic representation of the possible mechanisms of Volkmann’s contracture.

There is an association between supracondylar fractures, an absent radial pulse, and Volkmann’s contracture. When the concepts of compartment syndrome as a cause for Volkmann’s contracture became popular, forearm fasciotomies became the accepted treatment method to prevent this devastating complication. An absent radial pulse, which is most commonly associated with arterial injury, began to merge with the notion of compartment syndrome. This misconception has no doubt caused many physicians to delay treatment for a compartment syndrome while waiting for the radial pulse to disappear. Owing to these misconceptions, the

Artery

Vein

Venules

Arteriole

Capillary bed

FIGURE 15-5

FIGURE 15-4

An arterial injury is a disease of the large vessels, whereas a compartment syndrome is a disease of small vessels. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders Co., 1981, p. 22.)

Volkmann’s ischemic contracture of the forearm. The residual of an untreated forearm compartment syndrome in an 8year-old boy.

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usually described as a feeling of increased pressure and is localized to the affected compartment. It is not relieved by immobilization. Pain may be lacking if a central or peripheral sensory nerve deficit is superimposed. Other early symptoms include swelling, numbness, and weakness. The earliest and most objective finding is a tense compartment that is a direct manifestation of the increased intracompartmental pressure. The tenseness should be evident throughout the involved compartments. To evaluate this, all dressings must be removed. Although it is not possible, even with experience, to estimate consistently by palpation the degree to which intracompartmental pressures are elevated, the presence of significant tenseness throughout the compartment boundaries suggests a compartment syndrome. Conversely, if the compartment is palpably soft, the examiner may be reassured that, for the moment, compartment pressures are not elevated. Pain with passive stretch of the muscles in the involved compartment is a common finding that is usually associated with muscle ischemia. However, direct muscle injury or contusion may elicit this clinical finding. The volar compartment of the forearm is traversed by nerves (radial, ulnar, and median) that have a distal sensory distribution in the hand. The first sign of nerve ischemia is alteration of sensation, which is manifest early by subjective paresthesia in the distribution of the involved nerve, followed by hypesthesia and, later, anesthesia. Unless there is a superimposed sensory or peripheral nerve deficit, decreased sensation to light touch or pinprick in the distal sensory distribution is a very reliable sign of ischemia. The dorsal compartment of the forearm is not associated with a specific sensory nerve. Paresis secondary to nerve or neuromuscular junction ischemia and elevated intracompartmental pressure is a common finding. The paresis may be confusing, however, because it may be secondary to proximal nerve injury or guarding secondary to pain rather than to intracompartmental ischemia. Except in the presence of major arterial injury or disease, peripheral pulses and capillary filling are routinely intact in compartment syndrome patients. Although intracompartmental pressures may become high enough to cause ischemia of the muscle and nerve by occluding the microcirculation within the compartment, the pressures are rarely high enough to occlude the major arteries (Fig. 15-9). In our experience, the intracompartmental pressures usually do not exceed 80 mm Hg and are more commonly between 40 and 60 mm Hg. It has been suggested that absent pulses may result from vascular spasm secondary to elevated

Signs of Compartment Syndrome

FIGURE 15-6

A 3-year-old boy who sustained a supracondylar fracture. At the time of cast removal, his forearm had poor sensation and was contracted in the pronated and flexed position. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981, p. 88.)

signs and symptoms of arterial injury compared with those of compartment syndrome will be discussed in detail. Symptoms and Signs of Arterial Injury As with a compartment syndrome, pain out of proportion to that expected for the injury is the earliest symptom of arterial ischemia. The earliest clinical sign for an arterial injury is pain with passive stretch of the involved muscles. This usually will be associated with absent or decreased pulses, poor skin color, and decreased skin temperature. Other early findings are weakness and hypesthesia in a glove-like distribution. Symptoms of Compartment Syndrome The early diagnosis of a compartment syndrome depends on recognition of the signs and symptoms of increased intracompartmental pressure. The first and most important symptom of an impending compartment syndrome is pain that is greater than that expected from the primary problem (e.g., the fracture or contusion). The pain is

Chapter 15 Complications of Supracondylar Fractures of the Elbow

231

FIGURE 15-7

Causes of Volkmann’s contracture in 58 limbs (55 children). In this study, the supracondylar fractures accounted for half of these complications in the upper extremity. (From Mubarak, S. J., and Carroll, N. C.: Volkmann’s contracture in children: aetiology and prevention. J. Bone Joint Surg. 61B:285, 1979.)

intracompartmental pressures.12 Mubarak and colleagues have demonstrated that pressurization to as high as 80 mm Hg of the entire anterolateral compartment in a number of dogs produced only occasional transient spasm of the midsize vessels on angiography.

DIFFERENTIAL DIAGNOSIS Many traumatic events that precipitate a compartment syndrome or arterial injury can also produce a painful, swollen extremity. The diagnosis of the underlying problem (e.g., fracture or contusion) is obvious; the diagnosis of a superimposed ischemia is more difficult. Pain out of proportion to that expected for the injury and any sensory deficit must be explained. A compartment syndrome or an arterial injury also must be differentiated from a nerve injury, which is usually a

neurapraxia when it is associated with a closed elbow fracture or dislocation. The clinical findings of these three entities overlap, frequently making the diagnosis difficult, if not impossible, by clinical means. All of these problems may be associated with motor or sensory deficits and pain. Careful clinical evaluation is necessary to differentiate these entities (Table 15-1). As noted earlier, an arterial injury usually results in absent pulses, poor skin color, and decreased skin temperature. In contrast, a compartment syndrome routinely presents with intact peripheral circulation unless the underlying etiology is an arterial injury. A diagnosis of nerve injury is usually made by exclusion of the other two entities. Doppler blood flow studies, arteriography, and pressure measurements are frequently required to aid in the differential diagnosis of these three entities, especially if these problems are present in combination.

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Arterial occlusion

Typical Clinical Findings of Compartment Syndrome, Arterial Occlusion, and Neurapraxia

TABLE 15-1

Compartment Syndrome

Arterial Occlusion

Neurapraxia

Pressure increased in compartment

+

+

−

Pain with stretch

+

+

−

Paresthesia or anesthesia

+

+

+

Paresis or paralysis

+

+

+

Arterial ischemia (X hours)

Restoration

Postischemic swelling

From Mubarak, S. J., and Carroll, N. C.: Volkmann’s contracture in children: aetiology and prevention. J. Bone Surg. 61B:290, 1979. Compartment syndrome

Compartment syndrome ischemia (Y hours)

Fasciotomy Total ischemia = X hours + Y hours

FIGURE 15-8

Pathogenesis of postischemia-initiated compartment syndrome. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981.)

FIGURE 15-9

Schematic view of forearm compartment syndrome. Intracompartmental pressures are rarely high enough to occlude the major arteries of the compartment. However, the pressure is sufficient to cause ischemia of muscle and nerve by occluding the microcirculation within the compartment. (From Rang, M.: Children’s Fractures. Philadelphia, J. B. Lippincott Co., 1974.)

Differentiation of these entities is important because therapy for each is radically different. The neurapraxia accompanying a closed fracture is usually best treated by observation. Arterial injuries warrant immediate operative repair of the vessel, and a compartment syndrome necessitates immediate decompressive fasciotomy.

TREATMENT When evaluating a patient with a traumatized limb and a neurocirculatory deficit, the physician should document carefully the time of injury and examination. A thorough examination should include motor, sensory, and circulatory evaluation. In the case of a young child, in which patient cooperation is not possible, observations of finger movement should be documented while the circulation is objectively assessed by palpation of the pulses and by Doppler examination. When a neurologic deficit is observed in a painful, traumatized, and swollen limb, the physician must evaluate and treat the patient promptly. At this stage, one must differentiate the troublesome problems of compartment syndrome, neurapraxia, and arterial injury. Arterial Injury When an arterial injury associated with a supracondylar fracture is suspected, a Doppler examination should be performed. The velocity Doppler is an integral instrument in assessing the presence of peripheral pulses and is very useful for noninvasive documentation of pulses in the presence of a markedly swollen extremity. A quantitative Doppler technique has been described by Schoenecker and colleagues66 to detect significant asymmetry between the injured and an uninjured extremity in children with type III supracondylar humerus fractures. Arteriography is not recommended in an acute situation.67 Shaw and associates noted the risk of arteriography to be the following: (1) prolongation of ischemic time between fracture and reduction;

Chapter 15 Complications of Supracondylar Fractures of the Elbow

(2) arterial damage at the catheter insertion site; and (3) allergy to contrast material.67 After confirmation of distal forearm ischemia, an attempt to better align the fracture fragments should be made immediately in the emergency room. In extensiontype fractures, this is accomplished by extending the elbow, correcting any coronal plane deformity, and reducing the fracture by bringing the proximal fragment posteriorly and the distal fragment anteriorly (Fig. 15-10). Often, this simple maneuver will immediately restore distal circulation.33 If the distal circulation is not restored, a vascular surgeon should be notified, and the patient should be taken immediately to the operating room. All authors agree that the fracture should be reduced and stabilized by percutaneous pinning or, if necessary, open reduction and fixation. If the radial pulse does not return within 30 minutes, and signs of forearm and hand ischemia continue to be evident, then exploration of the brachial artery at the fracture site is recommended. In these circumstances, prophylactic fasciotomy of the forearm should be considered after brachial artery repair if the period of ischemia is more than 4 hours. An algorithm for the treatment of supracondylar humerus fractures associated with forearm and hand ischemia is represented in Figure 15-11.

233

FIGURE 15-10 A and B, Simple realignment of an ischemic limb may reduce the tension on the brachial artery and restore the distal circulation. (From Herring, J. A.: Tachdjian’s Pediatric Orthopedics, 3rd ed., 2002, p. 2148.)

Supracondylar fracture and ischemia

Anesthesia and operating room

Reduce fracture and stabilize

Absent pulse and ischemia

Intact pulse and soft compartment

Arteriogram ± Axillary block ±

Tight forearm compartment

Pressure measurement Observe < 30 mm Hg

Explore: repair artery

Ischemia > 4 hours

Explore: decompress compartment syndrome

≥ 30 mm Hg

FIGURE 15-11 Scheme for management of supracondylar fractures associated with upper extremity ischemia. (From Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981, p. 144.)

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Shaw and colleagues67 explored three cases and documented intimal tears with thrombus obstructing the brachial artery lumen. In two patients, the injured segment was excised and replaced by a saphenous vein graft; and prophylactic fasciotomy was also performed. One patient was noted to have brachial artery entrapment at the fracture site that was appropriately released. Schoenecker and associates66 recommend brachial artery exploration if Doppler-detectable pulses did not return within 30 minutes after fracture reduction. A vascular surgeon assisted with the exploration. Three of seven patients demonstrated interluminal damage or transsection, requiring saphenous vein graft. Four others demonstrated kinking or entrapment of the artery at the fracture site, with re-establishment of the pulses after mobilization. Garbuz and coworkers19 explored five brachial arteries and found a similar ratio of luminal damage, laceration, and entrapment of the arteries. One patient was treated with ligation, and had long-term claudication symptoms. Eight of 11 patients who initially had an absent radial pulse demonstrated a return of the pulse after the closed reduction. In three children, the radial pulse did not return, but no further treatment was required because the forearm and hand remained pink without any further neurologic deficits. This is known in the orthopedic literature as the “pulseless pink hand.” The Vancouver study group reviewed the pulseless pink hand in 13 patients following closed reduction and percutaneous pinning of the supracondylar fracture.65 They recommended color flow duplex scanning and MRA as a noninvasive safe technique for evaluating brachial artery patency and collateral circulation around the elbow. The vascular injuries in the 13 patients were studied; four had a thrombus or intimal tear. These patients underwent vein patch graft angioplasty. Urokinase infusion was used intra-arterially in four patients, and open thrombectomy was used in one. At follow-up, MRA studies of these patients showed a high rate of asymptomatic reocclusion and residual stenosis of the brachial artery. Thus, the investigators called into question the need for vascular reconstruction of intimal tears when the patient has a pink, well-perfused hand and MRA or other noninvasive studies that demonstrate adequate collateral circulation. They strongly recommended observation as the mainstay of treatment for these patients. In a recent survey of pediatric orthopedic surgeons, 60.5% of responding surgeons would monitor a pulseless pink hand for at least 24 hours following reduction and pinning. If the hand remained pulseless after 24 hours, the majority of respondents (61.2%) would continue to observe the extremity and monitor for adequate collateral circulation.49

Compartment Syndrome When the patient is cooperative, most compartment syndromes can be diagnosed clinically, and intracompartmental pressure measurement is only confirmatory. There are three groups of patients in whom difficulties in eliciting or interpreting the physical findings make measurement of intracompartmental pressure particularly valuable as a criterion for decompression:

1. Uncooperative or unreliable patients. A child with a supracondylar fracture will often be so frightened that careful motor and sensory evaluation is not possible. 2. Unresponsive patients. A patient with a head injury or one who is sedated and on a respirator with a swollen limb needs pressure measurement. 3. Patients with nerve deficits. When there is an associated nerve injury or arterial injury at the elbow, intracompartmental pressure measurement frequently is required to differentiate these problems from a compartment syndrome. Mubarak and colleagues recommend that any intracompartmental pressure greater than 30 to 35 mm Hg be considered for fasciotomy if it is combined with the clinical findings of a compartment syndrome. However, one must remember that any threshold pressure is a relative indication for decompression that should be tempered by the patient’s overall condition, blood pressure, and peripheral perfusion; the trend of the symptoms and signs; the trend of the intracompartmental pressures; and the cooperation and reliability of the patient.57 Bardenheuer2 was the first to report on fasciotomy in the forearm. Eichler and Lipscomb13 described an approach to a patient with a forearm compartment syndrome that included a division of forearm skin, subcutaneous tissue, and fascia. In 1972, Eaton and Green11 described a specific operative technique in which the skin incision began distal to the elbow flexion crease and medial to the bicipital tendon, extending distally in the longitudinal axis of the midforearm to the transverse flexion crease at the wrist. The forearm fascia was incised longitudinally along its full length. The epimysium of all poorly vascularized muscles was sectioned. The fascia was left open, and delayed closure with split-thickness skin grafts and relaxing incisions was performed 48 to 72 hours later. Neumeyer and Kilgore’s incision began adjacent to the medial epicondyle, extended obliquely across the antecubital fossa over the volar mobile wad, and returned to the midline in the distal forearm.59 It continued in a curvilinear fashion across the carpal canal to the midpalm. This report recommended wide exposure of all three possible areas of involvement: the volar and

Chapter 15 Complications of Supracondylar Fractures of the Elbow

dorsal compartments of the forearm and the intrinsic compartments of the hand. Closure was accomplished by split-thickness skin grafts after several days. Whitesides and associates77 described another operative approach in which the incision began above the elbow laterally and was carried transversely across the antecubital fossa to the proximal-medial forearm. The incision was continued distally along the ulnar border of the forearm to the wrist, where it curved laterally in the flexor crease of the wrist and extended into the palm in the thenar crease. The fascia was opened from above the elbow to the midpalm. The carpal tunnel and all neurovascular and muscular envelopes were opened fully. They noted that subcutaneous fasciotomy should never be performed in the forearm. The fascia was left open and was closed by split-thickness skin grafts 48 to 72 hours later. Similarly, Matsen and associates used the volar-ulnar approach. They frequently performed carpal tunnel release and epimysiotomy, as recommended by Eaton and Green.11 The advantage of this volar-ulnar approach is that the flexor tendons and median nerve are not left exposed in the distal forearm. The effectiveness of the volar forearm fasciotomy was evaluated initially in a series of cadaver experiments.21 The incisions used were the volar-ulnar incision described by Whitesides and associates77 and the curvilinear midline volar incision. Both incisions were effective in lowering pressures in the volar forearm, and both also lowered pressure within the mobile wad and dorsal regions in approximately half of the limbs. However, the curvilinear incision allowed easier exposure of the arteries and nerves of the forearm and the mobile wad. The volar forearm pressure generally fell to normal values when the antebrachial fascia had been divided from the lacertus fibrosus to the junction of the middle and distal thirds of the forearm. When the dorsal pressures remained elevated following volar fasciotomy, a dorsal fasciotomy was performed. A Volkmann contracture is the major complication of a compartment syndrome. Fortunately, the incidence of that complication following supracondylar fractures, as previously noted, has declined significantly in the past 40 years. With proper treatment of the elbow injury and early recognition and treatment of ischemia, Volkmann’s contracture is a rarely seen sequela of a supracondylar fracture. Many large series on the treatment of supracondylar fractures report no cases of Volkmann’s contracture when treated by Dunlap’s traction,10 overhead pin traction,6 or percutaneous pinning.14,43,69,70 Gelberman and colleagues20 reported no cases of Volkmann’s contracture in a study of supracondylar fractures. However, they noted that crush injuries or severe open injuries, when associated with compartment syndromes, resulted in considerable disability with decreased strength and limitation of forearm and hand

235

motion. In these cases, much of the functional loss can be attributed to the crush injury alone; the compartment syndrome is an additional insult.20 A complete discussion of the treatment of an established contracture is covered by Gelberman20,21 and others,57 and is beyond the scope of this discussion. Authors’ Prefered Fasciotomy Technique We prefer a single longitudinal curvilinear incision for decompression of the volar forearm (Fig. 15-12). This incision allows an easy approach to the antebrachial fascia and the transverse carpal ligament, as well as to the neurovascular structures of the forearm and the mobile wad. The incision is nearly identical to McConnell’s combined exposure of the median and ulnar neurovascular bundles, as described by Henry.31 A straight longitudinal incision is used for the dorsal compartment of the

FIGURE 15-12

Dorsal and volar forearm incisions. (From Gelberman, R. H., Garfin, S. R., Hergenroeder, P. T., Mubarak, S. J., and Menon, J.: Compartment syndromes of the forearm: diagnosis and treatment. Clin. Orthop. 161:252, 1981.)

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Part IV Conditions Affecting the Child’s Elbow

FIGURE 15-13 Cross-section of left forearm with wick catheter illustrating its position and fasciotomy incision. W, Wick catheter; 1, ulnar nerve; 2, ulna; 3, radius; 4, median nerve; 5, radial artery; 6, forearm fascia. (From Gelberman, R. H., Garfin, S. R., Hergenroeder, P. T., Mubarak, S. J., and Menon, J.: Compartment syndromes of the forearm: Diagnosis and treatment. Clin. Orthop. 161:252, 1981.)

forearm (see Figs. 15-2 and 15-13). Technique and postoperative care are described in detail elsewhere.20,21,57 It is clear that many factors influence the result of a supracondylar fracture associated with ischemia. However, the treating orthopedic surgeon must carefully assess the clinical findings and document them in the medical records. When appropriate, laboratory instruments such as Doppler blood flow studies, MRA (for a possible arterial injury), and intracompartmental pressure measurements (for possible compartment syndrome) should be performed to clarify the diagnosis. Treating these causes for forearm and hand ischemia promptly will result in the best results.

SURGICAL TIMING AND NEUROVASCULAR COMPLICATIONS A number of recent studies have investigated the association between surgical timing and perioperative complications in the treatment of closed, well-perfused,

displaced supracondylar humerus fractures in children.28,51,75 The groups from Cincinnati and Los Angeles were unable to identify any significant differences in the need for open reduction (2% to 13%), or the rates of pin tract infection (1% to 4%), iatrogenic nerve injury (2% to 4%), vascular injury recognized after surgery (2%), and compartment syndrome leading to Volkmann’s ischemic contracture (0%) when comparing patients with closed, well-perfused, displaced supracondylar humerus fractures treated 8 to 12 hours following the initial injury with those treated more than 8 to 12 hours after injury.28,51 More recently, a group from Edinburgh, Scotland, did demonstrate an increased need to perform an open reduction in patients with closed, well-perfused, Gartland type III supracondylar humerus fractures when surgery was delayed more than 8 hours following injury (33%) compared with those treated in less than 8 hours from the time of injury (11.5%), P = 0.05.75 All of these studies specifically excluded two of the most common indications that prompt the emergent treatment of supracondylar humerus fractures: open fracture and extremity ischemia. We do not recommend delayed treatment in those situations. At present, we will allow an 8- to 12-hour delay in the treatment of displaced supracondylar humerus fractures provided that the skin is intact and the neurovascular examination is normal. These patients are splinted in a position of comfort and are admitted for elevation/observation until definitive surgical treatment. Some fractures with marked displacement can be provisionally reduced in the emergency room to improve patient comfort and fracture position before splinting. Patients in whom the skin is compromised, the swelling is severe, or the neurovascular examination is abnormal are treated with closed reduction and pinning emergently.

OSSEOUS COMPLICATIONS Osseous complications of supracondylar humerus fractures include malunion, nonunion of the fracture, avascular necrosis (AVN) of the distal fragment, and myositis ossificans. Techniques for the management of these complications are discussed here. Stiffness after these fractures is discussed at length in Chapter 22. With current management techniques, good to excellent results should be anticipated in more than 90% of patients with supracondylar fractures.1 The most common significant complication is malunion, which is discussed last and in the greatest detail. Nonunion of the supracondylar fracture is virtually never seen, with only a few scattered anecdotal accounts in the literature. The near absence of nonunion with this fracture may be due to the rich vascular supply in the area, as

Chapter 15 Complications of Supracondylar Fractures of the Elbow

237

well as to the fact that the fracture tends to be more metaphyseal in location and extra-articular. The lateral condyle fracture, in which the incidence of nonunion or delayed union is much higher, is an intra-articular fracture, with synovial fluid bathing the surface of the fragments, a phenomenon absent in the supracondylar fracture.

AVASCULAR NECROSIS Despite the rich vascular supply, AVN has been reported in the distal fragment following a supracondylar humerus fracture.55 AVN of the capitellum as well as the trochlea has been reported, although both are extremely rare. The occurrence of AVN is much more likely to be associated with a condylar fracture, medial or lateral, than with a supracondylar humerus fracture. Condylar fractures require early and accurate diagnosis as well as prompt management to maximize successful osseous healing and minimize the development of future deformity. Even in widely displaced type III supracondylar fractures, Morrissy and Wilkins55 did not find a correlation between severity of the fracture and the extent of avascular changes, which are very rare. Because the capitellar blood supply enters the distal humerus laterally and distally, a fracture that exits the lateral column very distally may lead to avascular changes in this region. Similarly, low fractures exiting medially may be at increased risk for avascularity associated with the trochlea. Distal humeral AVN and the fishtail deformity may be associated with decreased range of motion, the development of a cubitus valgus deformity, and, occasionally, a subsequent tardy ulnar nerve palsy. Depending on which of the two vascular supplies to the growth centers is compromised, different deformities may develop. With elimination of the more lateral trochlear blood supply, such as may occur with a supracondylar humerus fracture with T intercondylar extension, a classic fishtail deformity of the distal humerus may occur (Fig. 15-14). The fishtail deformity is more frequently associated with an inadequately treated lateral condyle fracture. The deformity includes the loss of the normal crista dividing the capitellum from the trochlear groove and central involution of the distal articular surface. The central involution allows the proximal ulna to “settle” into the distal humerus. Clinically, the prominence of the olecranon normally seen during maximal flexion of the elbow is absent (Fig. 15-15). If both vessels feeding the distal humeral fragment have been compromised, complete aplasia of the trochlea may result. This condition will most likely lead to a progressive cubitus varus deformity and potential posterolateral rotatory instability of the ulnohumeral articulation. A tardy ulnar nerve palsy may also develop.

FIGURE 15-14 Trochlear blood supply. Medial and lateral vessels feed the trochlea; the severity of avascular changes as well as the type of resulting deformity is dependent on which vessel is injured. In this illustration, a central deficiency and fishtail deformity of the distal humerus would be expected to develop. (From Rockwood, C. A., Wilkins, K. E., and Beaty, J. H.: Fractures in Children, 4th ed., Vol. 3. Philadelphia, Lippincott-Raven, 1996.)

FIGURE 15-15 Fishtail deformity—loss of the olecranon prominence. Clinical findings of avascular necrosis (AVN) of the distal humerus can include depression of the prominence of the olecranon secondary to a central deficiency as demonstrated in this silhouette of flexed elbows as viewed from the patient’s head. Also cubitus varus or less likely valgus and diminished range of motion may be seen with AVN of the distal humerus.

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Causative factors include instability of the ulnar nerve over a hypoplastic medial condylar region and scarring or tethering as the nerve enters the flexor carpi ulnaris.16 In time, this leads to abnormal traction, stretching, and friction of the ulnar nerve as it moves over the medial epicondyle, producing a gradual progressive ulnar neuropathy.34 Management of the sequelae of distal humeral AVN is rarely satisfying. Surgical intervention for improvement of motion may be indicated in specific cases, if a vigorous physical program is unsuccessful. Cases of tardy ulnar nerve palsy are managed with anterior transposition of the ulnar nerve. Progressive angular deformity of the distal humerus may be attributable to either AVN or physeal injury. Physeal arrest, sporadically reported in conjunction with even mild supracondylar humerus fractures, appears similar to a nonunion but is rare.37,60 If it is detected early and the degree of physeal involvement is limited, physeal bar resection, although technically demanding, may be considered. Although the fishtail deformity itself is not amenable to

surgical correction, cubitus varus or valgus, which may occur in conjunction with either physeal arrest or AVN, can be corrected with a supracondylar osteotomy. Because the restoration of growth potential may not be possible in cases of AVN, as in some cases of physeal arrest, recurrent angular deformity may occur, depending on the age of the child, requiring multiple osteotomies over time. Other potential etiologies for loss of range of motion include myositis ossificans, soft tissue contracture or scar formation, osseous deformity producing a bone block to motion, and angulation at the fracture site. In cases in which the fracture has healed but flexion or extension is believed to be limited structurally by a bony block, excision of the tip of the olecranon with enlargement of the olecranon fossa may occasionally prove beneficial (Fig. 15-16). Osseous impingement is an uncommon cause of motion loss. The technique has been well described for the management of the more common impingement from degenerative changes of the elbow by Morrey.54

FIGURE 15-16 A, Teenage patient with open reduction and internal fixation of left supracondylar humerus fracture with markedly limited motion postoperatively secondary to arthrofibrosis as well as impingement of both the coronoid and olecranon fossae due to healing with collapse of the medial and lateral columns of the distal humerus. B, Three-dimensional computed tomography scan of elbow showing impingement of the olecranon fossa. C, Distal humeral osteoplasty was performed with removal of the tip of the olecranon, foraminotomy of the distal humerus, and débridement of impinging distal humerus proximal to the capitellum. The arc of motion of the elbow increased by 50 degrees postoperatively.

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MYOSITIS OSSIFICANS

ANGULAR DEFORMITY

Myositis ossificans is a potential complication of supracondylar humerus fractures, which if extensive, results in poor elbow motion. The phenomenon is not common and may even be self-limiting, with resolution over a 1- to 2-year course (Fig. 15-17). Siris71 found a 2% incidence in a 1939 review of 330 supracondylar humerus fractures, whereas more recent studies have reported an incidence of less than 1% and 0% by most authors. The occurrence and severity would intuitively be expected to be increased in cases treated with open reduction, particularly if the surgery is delayed from the time of the injury. In supracondylar humerus fractures treated with open reduction acutely, only one report identifies myositis as a postoperative complication.22 Even with delayed open management, Lal and Bhan42 found no cases of myositis ossificans in their report of 20 fractures treated with open reduction 11 to 17 days after injury. Surgical excision of the affected tissue should be performed only if the ectopic bone is clearly demonstrated to be causative of motion loss, conservative attempts to regain motion have failed, and adequate time from that of the injury has transpired such that the lesion is quiescent. Bone scan has been recommended in assessing the metabolic activity level of the lesion, but the editor favors the plain radiographic features of clear marginal delineation and trabecularization. Attempts to prevent heterotopic bone formation with low-dose external beam irradiation, and administration of oral nonsteroidal anti-inflammatory agents or oral disphosphonates are not warranted due to the rarity and self-limiting nature of this complication.30

Angular deformity of the elbow is the most common significant adverse sequela of a supracondylar humerus fracture. This condition may arise from growth disturbances such as a physeal injury or AVN, as outlined previously, or from the position in which the fracture healed. Malunion may result in either a flexion or extension deformity in the sagittal plane; a varus or valgus deformity in the coronal plane; and rotational deformity in the horizontal plane. Deformity may occur in any single plane or in a combination of planes. Although some remodeling of sagittal plane deformity can be expected, no significant improvement in coronal and horizontal deformity should be anticipated.4,15,40,52 Although cubitus valgus has been reported in association with supracondylar fractures of the humerus,8 cubitus varus is far more commonly reported as a complication of the management of these fractures. Cubitus varus has been termed a cosmetic sequela by numerous authors. This characterization may limit indications for corrective surgery, particularly in the modern medical environment. Tardy ulnar nerve palsy has been described in association with cubitus varus, although it is more commonly found secondary to cubitus valgus.17 Functional deficits and a potential increased risk of new injury as well as limitations of motion and discomfort have been well described in patients with cubitus varus. A correlation between residual cubitus varus following supracondylar humerus fractures and subsequent lateral condyle fractures has been noted.7 Thus, although the indications for surgical correction of cubitus varus do include poor cosmesis of

FIGURE 15-17 Myositis ossificans. A, Supracondylar fracture with myositis ossificans and a rigid elbow. B, Spontaneous resorption and remodeling with restoration of motion, lacking 20 degrees of flexion 7 months after injury.

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an unsightly deformity, one must also consider future function of the extremity and the risk for new injuries due to altered biomechanics of the elbow in varus.

INDICATIONS FOR CORRECTIVE SURGERY The goals of corrective surgery are (1) to restore the upper extremity alignment, (2) to restore range of motion, and hence, (3) to improve function to as near the preinjury state as possible. To achieve these goals, understanding of the anatomic nature and functional requirement of the deformity is necessary. Although simple collapse or impaction of the lateral column of the distal humerus will yield a cubitus valgus angular deformity, and the opposite is true for cubitus varus, rotation may contribute to either deformity and should at least be considered in the planning of corrective surgery. Graham24,25 stressed the contribution of rotation to changes in the carrying angle of the arm. Chess and colleagues5 stated that varus malalignment was the most important contributor to postoperative cubitus varus, but that internal rotation combined with varus accentuates the deformity. In apparent contrast, Mahaisavariya and Laupattarakasern48 reviewing anatomic findings at the time of corrective osteotomy concluded that rotation does not contribute to cubitus varus. Mitsunari and coworkers53 found an increased incidence of residual internal rotation deformity in patients with tardy ulnar nerve palsy following a supracondylar humerus fracture. Many techniques have been espoused for the correction of distal humeral malunions. These include closing wedge osteotomies with or without translation of the distal fragment, dome osteotomy, and complex triplane osteotomy, to name a few. The common concept is that each of these techniques addresses the potential components of the deformity to varying degrees.

SURGICAL APPROACH In considering surgical correction of a distal humeral deformity, one of the first steps is deciding on the surgical approach. A medial approach, which allows visualization and protection of the neurovascular bundles, has been advocated by some authors.39 One potential detraction from this approach is that manipulation of the neurovascular structures is necessary to gain access to the distal humerus. Also, particularly for cubitus varus, an osteotomy with lateral closing is difficult from the medial approach. The posterior approach has been advocated by several authors. This can be accomplished through a triceps-splitting, triceps-tendon transecting,27,61 or tricepssparing technique.27,61 Avascularity of the distal fragment has been reported to be associated with this tendon

FIGURE 15-18 Lateral approach to the distal humerus. The lateral approach is used to expose the distal humerus. The triceps is taken posteriorly; the brachioradialis and extensor carpi radialis longus are mobilized anteriorly from lateral supracondylar ridge; and the brachialis is dissected off the anterior distal humerus. The radial nerve passes laterally around the humeral shaft just proximal to this dissection, passing between the brachialis and brachioradialis before entering the supinator to become the posterior interosseous nerve. (Modified from Hoppenfeld, S.: Surgical Exposures in Orthopedic Surgery: The Anatomic Approach, 2nd ed. Philadelphia, J. B. Lippincott, 1984.)

transection.27 The posterior approach, particularly the first two techniques, affords excellent visualization of the distal humerus, being used with some frequency in displaced intercondylar distal humeral fractures. A long incision is necessary, as well as significant dissection, which risks postoperative adhesion formation. In one study of supracondylar humeral fractures, stiffness was noted in 21% of those managed with closed techniques but in 50% of those treated with open reduction through a posterior approach.61 In addition, intraoperative assessment of the magnitude of correction of the carrying angle can be difficult in the prone or lateral position. The lateral approach is the most frequently used and advocated approach to the distal humerus for the correction of cubitus varus.* The dissection is brought to the shaft of the humerus, distal to the area in which the radial nerve exits laterally from around the shaft. A subperiosteal plane is used to expose the humerus, as well as avoid injury to the medial neurovascular structures (Fig. 15-18). * See references 9,16,26,32,44,58,64,68,71,76.

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Valgus Flexion

FIGURE 15-19 Osteotomy templating. Distal humeral closing wedge osteotomy planned to remove more bone anteriorly to correct any extension deformity, as well as more laterally to correct cubitus varus. The magnitude of anterior closing wedge equals the difference in maximal elbow flexion comparing the injured elbow with contralateral. The magnitude of lateral wedge resection needed equals the degrees of ulnohumeral varus plus degrees of carrying angle of the contralateral elbow. (Modified from Hollinshead, W. J.: Anatomy for Surgeons, Vol. 3: The Back and Limbs, 3rd ed. Philadelphia, Harper & Row, 1982.)

OSTEOTOMY TECHNIQUES The next step in planning the correction of a distal humeral deformity is the nature of the osteotomy. As already outlined, there are various techniques to consider. The lateral closing wedge osteotomy is the most widely used and recommended technique. With a lateral closing wedge osteotomy, correction of the three aspects of distal humeral deformity following supracondylar fracture malunion are possible: cubitus varus, hyperextension, and rotation (Fig. 15-19). Some authors advocate a simple laterally based closing wedge, leaving the medial cortex intact as a hinge.3,23,39,50,62 Although this approach may have value in certain cases with limited deformity, flexion and extension are not well addressed, nor is rotational deformity. Wong and Balasubramaniam80 argue that correction of the rotational component is unnecessary. Also, as the size of the wedge required to achieve appropriate valgus alignment increases, so does the prominence of the distal fragment laterally.78 Owing to these constraints, a corrective closing

FIGURE 15-20 Fragment reduction and fixation. In correction of the deformity, the distal fragment is flexed to eliminate hyperextension, rotated to correct varus and provide the planned degree of valgus, and medialized to minimize lateral prominence of the capitellum. Fixation is provided with two to three threaded Steinmann pins, either solely from the lateral aspect of the humerus, or two from the lateral and one from medial, spaced as widely as possible at the osteotomy site for maximal rotational control. (Modified from Hollinshead, W. J.: Anatomy for Surgeons, Vol. 3: The Back and Limbs, 3rd ed. Philadelphia, Harper & Row, 1982.)

wedge osteotomy that is laterally and anteriorly based with medial translation of the distal fragment is preferred to obtain optimal results (Fig. 15-20).* If desired for greater osseous contact, a spike can be left laterally on the distal fragment to interlock with the proximal shaft, similar to a Wiltse distal tibial varus osteotomy.79 Uchida and associates72 described a three-dimensional osteotomy for the correction of cubitus varus. A posterolateral approach is used, and a complex biplane, tridirectional step cut osteotomy is performed, with fixation provided by screws. Although elegant in design and execution, this technically demanding osteotomy differs from a lateral closing wedge flexion osteotomy only in the extent and angle of bone surface contact. If poor postosteotomy healing is a concern, this technique offers extensive surface contact for osseous bridging. A dome osteotomy has been described that involves a posterior approach, marking the planned dome from a reference Kirschner wire, and uses K-wire fixation.38 * See references 9,16,18,26,29,35,36,41,58,61,68,71,73,74,76.

FIGURE 15-21 A, A 6-year-old boy with cubitus varus of the right elbow following supracondylar fracture. B, Anteroposterior (AP) view of his right distal humerus. C, AP view of the patient’s normal left distal humerus. D, AP view following closing wedge valgus and flexion osteotomy to correct cubitus varus. E, Lateral view 4 weeks postoperatively demonstrating restoration of sagittal alignment, distal humerus.

Chapter 15 Complications of Supracondylar Fractures of the Elbow

This technique allows correction of malrotation and avoids a potentially prominent lateral epicondylar region, but it does not address flexion/extension of the distal fragment. Also, this procedure is more technically demanding than that using the laterally based closing wedge osteotomy. In their report of 11 patients, Kanaujia and associates found that the outcome for all was satisfactory.

FIXATION TECHNIQUES The final consideration in surgical correction of the distal humerus malunion is fixation options for the osteotomy fragments. These include smooth Kirschner wires,62,71 threaded Steinmann pins, screws,72 screws with a wire tension band,3,16,45,50 plates and screws,9,32 and external fixation.42 The smooth Kirschner wire fixation has proven to be less than reliable, with a greater incidence of loss of correction compared with threaded fixation (Fig. 15-21). Adequate fixation and maintenance of alignment is reliably obtained and the buried pins can be retrieved in the future, particularly if the physis was crossed for optimal fixation. In the older, larger child, crossed screws may be used, although great care must be exercised to avoid unplanned translation of the fragments. The technique of screws paralleling the osteotomy, connected with a tension band wire, can be used only if good medial cortical integrity remains following the closing wedge osteotomy. Neither medial translation nor derotation is possible if this fixation is chosen. In the older adolescent, one-third tubular or 3.5-mm pelvic reconstruction plates with screws may be necessary to gain adequate fixation, particularly if early range of motion is planned postoperatively. External fixation is another option, although the size of the distal fragment is such that at most two pins could be used. Also, the inherent difficulties with pin tract care exist, which limits the attractiveness of this option. In summary, distal humeral malunion is not an uncommon complication of supracondylar humerus fractures. The most common deformity is cubitus varus, with varying components of extension and rotation of the distal fragment. The deformity is not purely cosmetic, because it alters the biomechanics of the elbow and may increase the risk to the patient of a future lateral condyle fracture. Corrective osteotomy with attention to detail is reliable and safe. An anterolaterally based closing wedge osteotomy with medial translation of the distal fragment is the treatment of choice. Subdermal threaded Steinmann pin fixation has proved adequate for the vast majority of cases, particularly the younger patient. The buried pins may be removed once healing has occurred, often as early as 6 to 8 weeks. Once osseous union is established, physical therapy can be used to maximize the patient’s range of motion.

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55. Morrissy, R. T., and Wilkins, K. E.: Deformity following distal humeral fracture in childhood. J. Bone Joint Surg. 66A:557, 1984. 56. Mubarak, S. J., and Carroll, N. C.: Volkmann’s contracture in children: aetiology and prevention. J. Bone Joint Surg. 61B:285, 1979. 57. Mubarak, S. J., and Hargens, A. R.: Compartment Syndromes and Volkmann’s Contracture. Philadelphia, W. B. Saunders, 1981. 58. Nassar, A.: Correction of varus deformity following supracondylar fracture of the humerus. J. Bone Joint Surg. 56B:572, 1974. 59. Neumeyer, W. L., and Kilgore, E. S., Jr.: Volkmann’s ischemic contracture due to soft tissue injury alone. J. Hand Surg. 1:221, 1976. 60. Nwakama, A. C., Peterson, H. A., and Shaughnessy, W. J.: Fishtail deformity following fracture of the distal humerus in children: Historical review, case presentations, discussion of etiology, and thoughts on treatment. J. Pediatr. Orthop. Part B 9:309, 2000. 61. Omer, C., Pestilci, F. I., and Tuzuner, M.: Supracondylar fractures of the humerus in children: analysis of the results in 142 patients. J. Orthop. Trauma 4:265, 1990. 62. Oppenheim, W. L., Clader, T. J., Smith, C., and Bayer, M.: Supracondylar humeral osteotomy for traumatic childhood cubitus varus deformity. Clin. Orthop. 188:324, 1984. 63. Ozcelik, A., Tekcan, A., and Omerolu, H.: Correlation between iatrogenic ulnar nerve injury and angular insertion of the medial pin in supracondylar humerus fractures. J. Pediatr. Orthopaedics, Part B. 15(1):58-61, 2006. 64. Rang, M.: Children’s Fractures, 2nd ed. Philadelphia, J. B. Lippincott, 1983. 65. Sabharwal, S., Tredwell, S. J., Beauchamp, R. D., Mackenzie, W. G., Jakubec, D. M., Cairns, R., and LeBlanc, J. G.: Management of pulseless pink hand in pediatric supracondylar fractures of humerus. J. Pediatr. Orthop. 17:303, 1997. 66. Schoenecker, P. L., Delgado, E., Rotman, M., Sicard, G. A., and Capelli, A. M.: Pulseless arm in association with totally displaced supracondylar fracture. J. Pediatr. Orthop. 10:410, 1996. 67. Shaw, B. A., Kasser, J. R., Emans, J. B., and Rand, F. F.: Management of vascular injuries in displaced supracondylar humerus fractures without arteriography. J. Orthop. Trauma 4:25, 1991.

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68. Siris, J. E.: Supracondylar fractures of the humerus analyzed; 330 cases. Surg. Gynecol. Obstet. 68:201, 1939. 69. Skaggs, D. L., Hale, J. M., Bassett, J., Kaminsky, C., Kay, R. M., and Tolo, V. T.: Operative treatment of supracondylar fractures of the humerus in children. The consequences of pin placement. J. Bone Joint Surg. 83A:735, 2001. 70. Skaggs, D. L., Cluck, M. W., Mostofi, A., Flynn, J. M., and Kay, R. M.: Lateral-entry pin fixation in the management of supracondylar fractures in children. J. Bone Joint Surg. 85A:702, 2004. 71. Sweeney, J. G.: Osteotomy of the humerus for malunion of supracondylar fractures. J. Bone Joint Surg. 57B:117, 1975. 72. Uchida, Y., Ogata, K., and Sugioka, Y.: A new threedimensional osteotomy for cubitus varus deformity after supracondylar fracture of the humerus in children. J. Pediatr. Orthop. 11:327, 1991. 73. Usui, M., Ishii, S., Miyano, S., Narita, H., and Kura, H.: Three-dimensional corrective osteotomy for the treatment of cubitus varus after supracondylar fracture of the humerus in children. J. Shoulder Elbow Surg. 4:17, 1995. 74. Voss, F. R., Kasser, J. R., Trepman, E., Simmons, E., and Hall, J. E.: Uniplanar supracondylar humeral osteotomy with preset Kirschner wires for posttraumatic cubitus varus. J. Pediatr. Orthop. 14:471, 1994. 75. Walmsley, P. J., Kelly, M. B., Robb, J. E., Annan, I. H., and Porter, D. E.: Delay increases the need for open reduction of type III supracondylar fractures of the humerus. J. Bone Joint Surg. 88B:528, 2006. 76. Weiland, A. J., Meyer, S., Tollo, V. T., Berg, H. L., and Mueller, J.: Surgical treatment of displaced supracondylar fractures of the humerus in children. J. Bone Joint Surg. 60A:657, 1978. 77. Whitesides, T. E., Jr., Hirada, H., and Morimoto, K.: Compartment syndromes and the role of fasciotomy, its parameters and techniques. Instr. Course Lect. 26:179, 1977. 78. Wilkins, K. E.: Residuals of elbow trauma in children. Orthop. Clin. North Am. 21:291, 1990. 79. Wiltse, L. L.: Valgus deformity of the ankle: a sequel to acquired or congenital abnormalities of the fibula. J. Bone Joint Surg. 54A:595, 1972. 80. Wong, H. K., and Balasubramaniam, P.: Humeral torsional deformity after supracondylar osteotomy for cubitus varus: its influence on the postosteotomy carrying angle. J. Pediatr. Orthop. 12:490, 1992.

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CHAPTER

16

Physeal Fractures of the Elbow Hamlet A. Peterson

ANATOMY AND GROWTH The elbow joint consists of the articulating surfaces of three epiphyses: the distal humerus, the proximal ulna, and the proximal radius. At birth, each epiphysis is one mass of cartilage, each with its own epiphyseal growth plate (the physis). With growth, the distal humerus develops four ossification centers1,2,4; the proximal ulna, two5; and the proximal radius, one.3 The lateral three distal humeral ossification centers eventually unite into one bony epiphysis; the fourth, the medial epicondyle, gradually separates from the others, becomes an apophysis, and no longer participates in longitudinal growth or joint articulation (Fig. 16-1). The two proximal ulna ossification centers unite to form one articulating epiphysis; its physis provides longitudinal growth, thereby qualifying it as a true epiphysis. Knowledge of the timing and pattern of ossification of these epiphyses, particularly the distal humerus, is essential in treating fractures of the elbow in children. The growth potential of these three physes is approximately 20% of their respective total bone length. This paucity of growth reduces the remodeling potential, requiring that fracture of any of these epiphyses be anatomically reduced.

EPIDEMIOLOGY The incidence of fracture of physes of the elbow is unknown. Of all elbow fractures in children, slightly more than half are supracondylar fractures (Table 16-1). The vast majority of the remaining half are physeal fractures. When studying physeal fractures at all sites, the relative frequency of elbow fractures varies widely in different series.8,9,12,15-20 The only data available from a population-based study were gathered in Olmsted County, Minnesota, from 1979 to 1988.20 This study reported 951 cases of physeal fracture; 47 (5%) were in the elbow. Of these, 37 (3.9%) were in the distal humerus, 6 (0.6%) in the proximal radius, and 4 (0.4%) in the proximal ulna. Because elbow fractures in children

are often referred to tertiary treatment centers, these percentages will be higher in nonpopulation-based studies. Analyzing data of elbow fractures is further complicated by difficulties in separating supracondylar fractures from physeal fractures of the distal humerus; by the vagaries of ossification of the multiple secondary centers of ossification of the distal humerus1,2,4; by the inclusion or exclusion of fractures of the medial epicondyle, which is an apophysis rather than an epiphysis; by imprecise definition between olecranon and physeal fractures of the proximal ulna, and by the difficulty in distinguishing radial neck fractures from those that involve the radial physis. When physeal fractures of the elbow are considered as a separate category (excluding supracondylar fractures), 60 percent occur in the distal humerus. In one series,9 fracture of the distal humeral lateral condyle was 26%; followed by radial head, 23%; medial epicondyle, 22%; proximal ulna, 17%; T-intercondyle, 4%; medial condyle, 3%; lateral epicondyle, 3%; and separation of the entire distal humeral epiphysis (typically occurring only in infants and young children), 2%.

CLASSIFICATION Many classifications of physeal fractures have been proposed.18,22 The classification of Salter-Harris24 has been the most frequently used over the past four decades. There have been no case reports of acute physeal compression injury (Salter-Harris type V) of the distal humerus, proximal radius, or proximal ulna recorded in the literature. Speculation suggests that acute compression injury (type V) of any physis is unlikely and may not exist.23 Supracondylar fractures of the distal humerus often have fracture lines extending distally into the physis, making them type 1 Peterson physeal fractures (Fig. 16-2).18,88 Fractures of the proximal radius metaphysis (neck) (see Fig. 16-7M), and of the olecranon (see Fig. 16-8), frequently extend proximally into the physis,18,184 also making them Peterson type 1 fractures. Therefore, the Peterson classification18,22 is used in the remainder of this chapter.

EVALUATION Any recent abnormality or change in a child’s elbow, with or without a history of injury, deserves careful physical examination, including vascular and neurologic evaluation.49-51 This will avoid the uncomfortable situation of finding a postreduction vascular or neurologic deficit without knowing the prereduction status.

Chapter 16 Physeal Fractures of the Elbow

0–1 yr

2–4 yrs

5–7 yrs

8–9 yrs

10–12 yrs

247

13 yrs

FIGURE 16-1

Distal humerus epiphysis growth centers at various ages. At birth, the physis is transverse and the epiphysis is one cartilaginous mass. By age 2 years, the capitellar ossification center is usually present.1 The physis still is relatively linear and transverse. At ages 5 to 7 years, there is mild obliquity of the epiphyseal growth plate to the longitudinal axis of humerus and beginning ossification of the medial epicondyle.4 Trochlear ossification begins at 8 to 9 years, is irregular with indistinct margins, and often appears as multiple fragments. At ages 10 to 12 years, a projection of metaphyseal bone separates the medial epicondyle from the major distal epiphysis, which now contains three ossification centers—capitellum, trochlea, and lateral epicondyle.2 These three ossification centers unite with each other in the 13th year and to the humeral epiphysis by the 16th year, earlier in girls. There is wide variation of ages of these occurrences between genders and among children, but the sequence is constant. (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

TABLE 16-1

Relative Frequency of Elbow Fractures in Children*

Year

Author†

SupraCondylar

1960

Fahey7

231

54

320 551

1986 TOTAL

Landin ‡

Percent

11

57.3

Lateral Condyle

Medial Condyle

Epiphyseal Separation

Medial Epicondyle

Lateral Epicondyle

6

1

–

38

3

67

4

–

–

48

121

10

1

–

86

0.1

–

12.6

Inter Condyle

1.0

8.9

Proximal Ulna§

Total

33

20

386

–

95

42

576

3

128

62

962

0.3

Proximal Radius‡

13.3

6.4

99.9

*Articles reporting only one or two of the three elbow bones are not included. † The Fahey data include 300 cases reported by Maylahn and Fahey in 1958,13 which documents the medial condyle and lateral epicondylar fractures. ‡ Includes both radial neck and head (physeal) fractures. § Includes both ulnar olecranon and physeal fractures of the proximal ulna. Adapted from Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

Imaging possibilities of cartilage and osseous structures are numerous. True anteroposterior and lateral roentgenographs of good quality are essential for evaluation of the injured pediatric elbow. Soft tissue as well as osseous structures must be clearly discernible. An intra-articular hematoma may displace the posterior fat pad of the distal humerus (the fat pad sign), which may be the only demonstrable change in an undisplaced or spontaneously reduced intra-articular fracture.26,47,94 Symmetric views of the contralateral elbow provide a valuable basis for comparison in assessing injury.48 This is particularly true in the pediatric elbow because of the

wide variance in the ages at which the multiple ossification centers appear. Anteroposterior varus and valgus stress views,35,81,143 and oblique views of the injured or of both elbows are also helpful.48 In younger children in whom the cartilaginous proportion of the epiphysis is high, arthrography,25,26,28,36,40,42,52,143 ultrasonography,29,31,32,44,53 and magnetic resonance imaging (MRI)33,34,41,44,46,119 play important roles in defining the injury. In older children, with predominantly osseous epiphyses, tomography37 and computed tomography (CT)27,30 may be of value.

248

Part IV Conditions Affecting the Child’s Elbow

1

2

3

4

5

6

FIGURE 16-2 Peterson classification of distal humeral physeal fractures in children. (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

TABLE 16-2

Physeal Fractures of the Distal Humerus by Age and Gender in Olmsted County, Minnesota,

1979-198820 Age

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Total

Boys

1

1

2

2

2

2

5

0

0

1

0

2

1

2

2

3

26

Girls

0

0

0

0

2

2

1

2

0

2

0

1

1

0

0

0

11

Total

1

1

2

2

4

4

6

2

0

3

0

3

2

2

2

3

37

From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

Chapters 6 and 12 of this textbook also review imaging techniques that aid in evaluating anatomy, development, and pathology of children’s elbows.

MANAGEMENT In a study of 698 childhood fractures in all bones, only 7.4% were treated operatively.6 However, fractures about the elbow were operated on 50% of the time. It is paramount that physicians both study each elbow fracture carefully and keep abreast of current literature to choose the best treatment for each fracture.

DISTAL HUMERUS EPIDEMIOLOGY Fractures of the distal humeral physes have two peculiarities when compared with injuries to other physes.17 The age distribution for all physeal fractures is a bellshaped curve, with the peak at age 11 to 12 years for girls and age 14 years in boys.17,20 The distal humerus has a bimodal age distribution, with a larger peak occurring at 2 to 7 years and a second smaller peak occurring at 11 to 15 years (Table 16-2). This bimodal age distri-

Physeal Fractures of the Distal Humerus by Type in Olmsted County, Minnesota, 1979-198820 (Peterson Classification)

TABLE 16-3

Type

1

Number

2

Percent

5.4

2

3

5

8

13.5

21.6

4

5

6

Total

1

21

0

37

2.7

56.8

0

100.0

From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

bution may be related to the preponderance of supracondylar (actually transcondylar) fractures, which are predominant at ages 5 to 10 years. The second departure from other physes is the type of fracture. At most other sites, type 2 is the most common fracture. In the distal humerus, more than 50% of physeal fractures of the distal humerus are type 5 (Table 16-3), most likely associated with the preponderance of lateral condyle fractures (see Table 16-1). The changing anatomy of the distal humeral physis during growth (see Fig. 16-1) predisposes it to specific fractures at different ages.19 Although any fracture type can occur at any age, from birth to age 2 years, the most

Chapter 16 Physeal Fractures of the Elbow

common fracture is epiphyseal separation (type 3). From age 2 to age 6 years, type 3 fractures become less common and types 2, 4, and 5 become more common. By age 6 to 10 years, shear type 2 and 3 fractures are rare and type 5 fractures, particularly of the lateral condyle, predominate. During ages 10 years to maturity, type 5 fractures and avulsion fractures of the medial epicondyle are the most common. These patterns provide a basis for presenting the fractures by age.19

NEWBORN TO 2 YEARS The epiphysis of the distal end of the humerus is one large cartilaginous mass during the first 2 years of life (see Fig. 16-1). Its interface with the metaphysis is smooth and transverse. Therefore, transverse, shear-type fractures totally within the physis are the most common fracture in the newborn,39,54,55,57,59,61,62,64,67-69,72,74-78 and in infants.36,56,60,63,66,70,73,79 These fractures tend to be reported separately and not in case series (see Table 16-1). They are typically types 2 and 3 (see Fig. 16-2).70 The entire epiphysis usually is displaced posteromedially60,61,67 but may be displaced medially,63,64,75,79 anteriorly,9,65 posteriorly, or laterally, depending on the mechanism of the injury. Rotatory malalignment may accompany displacement or occur alone. This can predispose to cubitus varus.59 Injuries of types 4 and 5 are theoretically possible, but at this age, they are more difficult to diagnose because the epiphysis is primarily cartilaginous in very young children. Injury with mild displacement may go undetected in abused children who present late for medical attention.25 Types 2 and 3 fractures frequently are misdiagnosed as elbow dislocations.56,57,60,64,66,71,75,83,85 Arthrography,25,26,28,36,40,42,52,57,63,71,83 ultrasonography,31,32,44,53,74,76 and MRI44,58,69,74,77 in these young children may aid in establishing the correct diagnosis. Treatment of type 1, 2, and 3 fractures consists of aligning the epiphysis with the metaphysis. Precise anatomic reduction is desirable but not necessary.9 Usually, this can be obtained by closed manipulation or traction.57,64,66,69,75,85 Immobilization with the elbow in 90 degrees of flexion and forearm pronation for 3 weeks is usually adequate.60,66 Because the entire epiphyseal growth plate usually remains with the epiphysis, damage to the growth plate is uncommon, and the potential for resumption of normal growth is good. The prognosis in these cases is favorable; minor malalignment usually corrects itself with normal growth and development, and physeal growth arrest is uncommon. Percutaneous pin fixation or open reduction25,59 is rarely necessary. Only four cases have been reported in which open reduction and internal fixation were performed late because of severe malalignment or interposition of soft tissue.55,71,86

249

AGES 2 TO 6 YEARS In early childhood, the growth plate gradually becomes more oblique distally and medially, from the lateral to the medial epicondyle (see Fig. 16-1). This obliquity of the epiphyseal line may account in part for the frequent lateral displacement of the epiphysis and the difficulty of maintaining accurate reduction. The ossification center of the capitellum may appear as early as 6 months and always by 2 years of age (see Fig. 16-1).1,83 This ossification center is initially oval and provides valuable orientation for alignment of the radial diaphysis. In the normal elbow roentgenograph, a line drawn through the radial diaphysis always passes through the capitellar ossification center in any projection. This aids in differentiating elbow dislocation from fracture. In a distal humeral epiphyseal separation, the capitellar ossification is aligned with the radius, regardless of degree of displacement, but is not properly positioned on the humerus. If the radius does not align with the capitellar ossification, there is radiohumeral subluxation or dislocation. Type 2 and 3 fractures are common.80 As age increases, type 2 and 3 fractures are progressively less common, presumably due to a more irregular and stable physis. Type 4 fractures are not common at this age but are a source of frequent complication, usually nonunion. They may occur on the medial condyle, which when not ossified makes diagnosis by routine roentgenographs very difficult (Fig. 16-3). When there is significant swelling medially and normal osseous contour, supplemental imaging is necessary. Soft tissue enhancement techniques and stress views are valuable, but if they are not diagnostic, ultrasonography, arthrography, or MRI should be considered. Type 5 fractures are common at this age, and their differentiation from type 2 fractures is difficult and important because displaced type 5 fractures frequently develop nonunion if left untreated (Fig. 164).71,75,78,102,107,110,112,123,130,137 Supplemental imaging, such as arthrography, ultrasonography, or MRI, should be considered. A coronal plane transcondylar fracture pattern has been described.98 All displaced type 5 fractures require anatomic reduction and maintenance of reduction. Attempts to accomplish this with immobilization in a cast frequently lead to subsequent displacement of even nondisplaced or minimally displaced fractures of the lateral condyle. This contributes to significant complications. Because so much of the distal humerus is still only cartilage, closed reduction with percutaneous pinning is also not advised. The bone and pins can be visualized roentgenographically, whereas the cartilage cannot. Open reduction and internal fixation (usually smooth wires) should be considered for any displaced fracture at this age.

250

Part IV Conditions Affecting the Child’s Elbow

FIGURE 16-3

A 5-year-and-1-month-old boy with type 4 fracture of right medial condyle (trochlea). A, Anteroposterior roentgenograph of both elbows (the right elbow is the image on the left). Patient had swelling and tenderness medially. There is mild medial displacement of the radius on the capitellum and of the ulna on the humerus on the right as compared with the left. B, Lateral view of both elbows (the right elbow is the image on the left) shows more soft tissue swelling and less joint congruity on the right elbow. The roentgenographs were interpreted as showing no osseous injury, and no treatment was given. C, Anteroposterior and lateral views at age 8 years. The patient had no pain or functional impairment. Note slight cubitus varus and beginning ossification of displaced, nonunited medial condyle.

Chapter 16 Physeal Fractures of the Elbow

FIGURE 16-3 cont’d

251

D, At age 18 years 1 month, the patient continues to have no pain or functional impairment. E, At age 31 years 5 months, 26 years after fracture, the patient returned with ulnar sensory neuropathy. The nonunion persists, and the cubitus varus is unchanged. F, Patient lacks the final 10 degrees extension and 30 degrees flexion. Note overgrowth of the head of the radius. At the time of the original injury, the presenting clinical findings and subtle roentgenographic changes were sufficient to warrant further evaluation. Better quality routine roentgenographs, varus-valgus stress views, or an arthrogram (and today magnetic resonance imaging) should have resulted in a diagnosis. Open reduction and internal fixation would have been indicated.

FIGURE 16-4

A right-dominant boy, age 2 years 7 months, fell off a bunk bed, injuring his left elbow. A, Oblique roentgenograph shows fracture of the lateral metaphysis. This was regarded to be a type 2 injury, with good prognosis for union and subsequent growth. Note, however, that this could be a type 5 injury, with intra-articular fracture and a poor prognosis. The best way to differentiate these injuries is by arthrography or magnetic resonance imaging. B, Lateral view shows excellent alignment. A cast was applied and multiple roentgenographs in the cast over the next month showed maintenance of position. C, Cast removal 6 weeks after injury. Motion was begun. The fragment was displaced. D, Fifteen months after injury: established nonunion. It now is obvious that this was an intra-articular type 5 injury, because the lateral condyle fragment is displaced proximally. E, Two years 9 months after injury, the patient was referred for treatment. The chief complaint is increasing valgus deformity. No pain or functional impairment. F, Five weeks after osteosynthesis. G, Age 6 years 10 months: union with persistent cubitus valgus. H, Three weeks postoperative arcuate varus osteotomy. Note fracture of the proximal two Crowe pins (arrows), probably from stress of pins holding the osteotomy. The pins were removed. A cast was applied for an additional 3 weeks. I, Age 10 years 3 months: union of lateral condyle with physeal closure, and relative overgrowth of medial epicondyle and proximal radius on left. J, Right elbow comparison. K, Lateral normal right elbow. L, Lateral left elbow. Elbow flexion right, 5 degrees hypertension to 145 degrees; left, 5 to 145 degrees.

Chapter 16 Physeal Fractures of the Elbow

An occasional complication of any distal humeral fracture at this age is the fishtail deformity.43,60,84,87 This occurs most commonly after supracondylar, medial, or lateral condylar fractures and consists of an Λ-shaped distal humeral articular surface. It is caused by premature arrest of the central portion of the physis, which may be due to central longitudinal malunion, avascular necrosis, or central physeal arrest without malunion or avascular necrosis. The deformity is often mild, with no functional impairment, but at this age can be marked with significant consequences.18,84

AGES 6 TO 10 YEARS By 6 years of age, the epiphyseal growth plate begins to become irregular and obliquity increases (see Fig. 16-1). A projection of metaphyseal bone begins to separate the medial epicondyle from the trochlea, adding greater stability to the physis. Therefore, shear-type injuries, such as types 2 and 3 fractures, become less common.96 On transverse section, the physis remains irregularly oval, whereas that of the metaphysis becomes elongated in the coronal plane and thin in the sagittal plane. Thus, the strength of the physis is, at this age, greater than the strength of the metaphysis. Most injuries in this age group are, therefore, supracondylar fractures. The decreased area and elongated contour of bone contact in supracondylar fractures make possible rotation and subsequent tilting of the distal fragment (cubitus varus). Because the area of fracture contact is greater with physeal fractures, rotation, tilt, and subsequent cubitus varus are less likely than for supracondylar fractures.60 At this age, fractures of the physis are usually longitudinal or oblique type 5 of either the lateral or the medial condyle.

LATERAL CONDYLE Fractures of the lateral condyle are relatively common, constituting approximately 10% to 15% of all fractures in the region of the elbow (see Table 16-1). They are the most common physeal fracture of the elbow. They occur in children between the ages of 2 and 16 years104 but are most common between 6 and 10 years of age.90,103,117,133,139,142 The mechanism of injury is usually a varus stress with the elbow in extension.122 The lateral condyle may fracture during elbow dislocation.143 Less commonly, pre-existing cubitus varus may predispose to fracture of the lateral condyle.106 The portion of metaphyseal bone attached to the capitellar and lateral epicondylar epiphysis may be large or small. The most important consideration is that this fracture is both intra-articular and transphyseal. The epiphyseal portion of the fracture may traverse the

253

ossification center of the capitellum but is often entirely through cartilage and therefore not visible on roentgenographs. Because this fracture involves both the articular surface and the physis, anatomic reduction is necessary and must be maintained until the fracture has united. If the fracture is undisplaced and stable, external immobilization by a long arm cast with the elbow in 90 degrees of flexion for 4 weeks will suffice.104,105 Frequent roentgenographic follow-up to assess maintenance of reduction is essential. If there is displacement, reduction and internal fixation will prevent redisplacement. If the fracture can be reduced or closed, pins inserted percutaneously may be used for fixation to prevent redisplacement.92,105 Some authors129 recommend arthrography to ensure a congruent joint surface before proceeding with percutaneous pinning. In most instances, however, open reduction and accurate replacement by direct vision is necessary. The reduction must be held by firm internal fixation, preferably metal rather than suture.89,110,113 Smooth pins, small in diameter, are the standard.101,105,115,142 Screws are preferred by some authors126,136 and biodegradable pins by others.93 Insertion of fixation devices from metaphysis to metaphysis and from epiphysis to epiphysis is preferred. However, because the trochlear cartilage is not ossified and not visible on roentgenographs, the pins may necessarily pass from epiphysis to metaphysis, crossing the physis obliquely. These pins should be removed within 3 weeks to prevent premature partial growth arrest. Pins not crossing the physis should remain in situ until there is some roentgenographic evidence of fracture healing, which occurred after approximately 6 weeks in one study.105 Fractures with early pin removal can be protected with additional long arm cast.105 Threaded pins predispose to premature partial physeal arrest and should not be used across a physis. Skeletal traction for elbow physeal fractures should be used only temporarily in children with multiple injuries. In one series of 33 lateral condylar fractures, four untreated cases all developed nonunion, 12 treated by closed reduction and immobilization had six with “poor results,” and 17 treated by open reduction and nailing had three with poor results.14 Untreated and inadequately treated cases are frequently complicated by malunion and nonunion, and these cause deformity, loss of motion, degenerative arthrosis, and tardy ulnar neuropathy.10,14,90,95,99-102,110,116,126,128,131,140,144,147,156,162 There is no agreement on the management of these complications, although many authors recommend osteosynthesis, combined with corrective osteotomy for significant deformity.89,98,99,108,112,121,125,128,134,145 Lateral prominence of the elbow is common after lateral condyle fracture (Table 16-4). This rarely is trou-

254

Part IV Conditions Affecting the Child’s Elbow

blesome or requires treatment. Varus or valgus deformity is also common (Table 16-5) and may be due to malposition of the fragment or to true overgrowth of the capitellum and its physis. Overgrowth is an interesting phenomenon and occasionally occurs even following successful management of a lateral condyle fracture.97,118,146,147 Although this may produce measurable cubitus varus, functional impairment is rare, and treatment is often for cosmetic improvement. Premature physeal closure113,146 has been noted in up to 20% of lateral humeral fractures. The premature Lateral Elbow Prominence Following Lateral Condyle Fracture

TABLE 16-4 Year

Author*

1975

Jacob122

20

2

10.0

1985

Rutherford135

36

8

22.2

32

13

40.6

28

28

100.0

116

51

44.0

2001 2001

No. Cases

114

Hasler Skak

138

Total

No. Prominence

Percent

*All articles have more than one author; see reference list. From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

TABLE 16-5

MEDIAL CONDYLE Fractures of the medial condyle83,84,86,87,102,108,109,148-156 are much less frequent (see Table 16-1) perhaps because of normal cubitus valgus and because of the projection of metaphyseal bone between the trochlea and medial epicondyle. They occur in children of all ages, with the peak age between 6 and 10 years in most series. Fractures of the medial condyle may result from a fall on the apex of the flexed elbow or from an avulsion valgus stress injury on an extended elbow.67,153 Marked swelling on the medial side of the elbow is usually present (see Fig. 16-3). Some occur before the trochlea is ossified. Therefore, the displaced fragment consists of a portion of bone from the medial side of the lower humeral

Varus/Valgus Deformity Following Lateral Condyle Fracture

Year

Author*

1942

Kini125

1971

fusion is more often complete than partial. Complete physeal closure causes no angular deformity, and the cessation of growth results in only minor relative shortening compared with the contralateral humerus. This usually results in no functional or cosmetic impairment. Premature partial lateral closure sufficient to cause progressive cubitus valgus is uncommon. Partial closure of the center of the physis, where a fracture crossed the physis and epiphysis, leads to a disturbance of growth referred to as a fishtail deformity.10,84,101,126,142

No. Cases

113

Hardacre

118

Varus (15 degrees)

Percent

7

2

29

1

14

23

1

4

4

17

1974

Holst-Nielsen

39

23

59

4

10

1974

Loyd127

34

4

12

0

0

43

2

5

0

0

26

8

31

0

0

1985 1985

111

Foster

135

Rutherford 140

1985

So

14

5

36

1988

Dhillon108

14

6

43

5

36

40

12

30

6

15

1988

Morin

132 144

–

1988

Van Vugt

10

3

30

1989

Jeffrey

124

24

4

17

1

4

1989

Kröpf126

16

6

38

0

0

21

5

24

2

10

63

9

14

3

5

374

90

2001 2001

Skak

138 141

Thomas Total

24.1

–

–

26

–

7.4†

*Most articles have more than one author; see References. † 26 of 350 cases in articles in which valgus deformity was recorded. From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

Chapter 16 Physeal Fractures of the Elbow

metaphysis, along with the cartilaginous trochlea and the ossified medial epicondyle. The unossified portion of the trochlea is not seen on the roentgenograph. Thus, if the fracture occurs before ossification of the trochlea, it may be mistaken for a fracture of the medial epicondyle. If the diagnosis is not made and the injury is treated nonoperatively as an avulsion fracture of the medial epicondyle, a poor functional result can be anticipated.82,151 In addition to the factors of articular congruity and growth plate alignment, fractures of the medial condyle are important because of its proximity to the ulnar nerve. Anatomic reduction, therefore, is mandatory to avoid tardy ulnar palsy as well as nonunion or malunion. These fractures usually require open reduction and rigid internal fixation. Only if the fracture is undisplaced may this fracture be treated by cast immobilization alone.150 The complication rate is high.155 Fractures may involve both condyles, with a split through the center of the articular surface (Fig. 16-5D).161 These fractures are analogous to the adult Tintercondylar fracture, are frequently comminuted, and fortunately, are not common. They are often the result of direct force and therefore may be open fractures. This is an unstable situation that requires open reduction and internal fixation.9

AGE 10 TO MATURITY The growth plate obliquity and irregularity continue to increase (see Fig. 16-1). The medial epicondyle and the trochlea are completely separated by a projection of metaphyseal bone. The medial epicondyle does not articulate with the ulna or contribute to the longitudinal length of the humerus. All four ossification centers are now visible roentgenographically. Trochlear ossification

A FIGURE 16-5

B

255

is frequently irregular and fragmented, simulating fracture. The trochlea, capitellum, and lateral epicondyle fuse to each other in approximately the 13th year (earlier in girls) before uniting with the humerus.1 Transverse shear-type type 2 and 3 physeal fractures are now virtually impossible (only one case has been illustrated in the literature18), except for the medial epicondyle. This conjoined epiphysis later fuses with the shaft, usually by the 16th year. Once fused, growth ceases and growth alteration following fracture is no longer possible. Injuries involving the conjoined epiphysis at this age are nearly always type 5. Lateral and medial condylar fractures both occur in this age group120 (see Fig. 16-5B and C). Medial condylar fractures129,163 are more common than they are at younger ages but are still less common than lateral condylar fractures. Both require open anatomic reduction and internal fixation. The T- or Y-type fracture (see Fig. 16-5D)131,159 is more frequent than at younger ages and usually requires open reduction and internal fixation. A minimally displaced fracture may be treated by reduction and percutaneous screw fixation.157 A posterior surgical approach gives excellent visualization and an opportunity for reduction and fixation of the multiple fragments.158 The triplane fracture is a type 5 fracture variation, usually found in the distal tibia. It has been reported in the distal humerus,160 and, because it involves both articular and physeal cartilage, it should be treated by anatomic reduction and maintenance of reduction. Premature closure of the physis is frequent at this age with any type of injury. The premature closure, however, is nearly always complete, and angular deformity, which would result from partial closure, is rare. Because the distal humerus contributes only 10% of the longitudinal length of the entire arm, early growth arrest at this age rarely causes noticeable arm length discrepancy.

C

D

Common distal humeral physeal fractures at ages 10 years to maturity. Normal distal humerus (A), type 5 injury of the lateral condyle (B), type 5 fracture of the medial condyle (C), type 5 fracture of both medial and lateral condyles (D). (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

256

Part IV Conditions Affecting the Child’s Elbow

MEDIAL EPICONDYLE The medial epicondylar apophysis is extra-articular and is usually roentgenographically present (ossified) by age 5 years (see Fig. 16-1). Multicentric ossification centers have been demonstrated and give a fragmented appearance. Awareness of this normal variant may obviate misdiagnosis. The medial epicondyle matures slowly and is the last of the six epiphyses of the elbow to unite with its adjacent metaphysis; as late as the 19th year in men.4 The medial epicondyle is located slightly posteriorly, rather than strictly medially, which may cause confusion in roentgenographic interpretation.4 Oblique roentgenographs of both elbows are sometimes necessary to determine whether the epicondyle on the injured side is in an abnormal position. Fractures of the medial epicondyle constitute nearly 10% of all fractures of the elbow region (see Table 161),47 and usually occur between 9 and 15 years of age.6,165,166,173 The injury is unusual in younger children. The mechanism of injury is usually a valgus stress of the joint, which produces traction on the medial epicondyle through the flexor muscles. Arm wrestling is not a common activity among children but may result in this fracture.172,173 The fracture is usually type 3, although types 2, 4, and 5 have been noted.6,9 The epicondyle is always displaced distally because of the pull of the flexor muscle mass origin. It may be dislocated into and entrapped in the elbow joint, associated with opening of the joint by valgus stress. The entrapped epicondyle must be extracted from the joint and reduced. This is best done by open surgery, because manipulative maneuvers are unlikely to remove it from the joint, reduce it, and render it stable. About half of the cases are associated with partial or complete dislocation of the elbow,164,169,170,175 usually posterolateral dislocation. Nowhere in the discussion of physeal injuries of the elbow is there a greater divergence of opinion concerning treatment than in medial epicondylar fractures. Recommendations range from performing open reduction in virtually all cases, to no surgical treatment for any case (other than for intra-articular epicondyle entrapment). The fear of painful pseudarthrosis following nonoperative treatment has been cited for using open reduction and internal fixation in nearly every case, even with minimal (1-mm) separation.9 Conversely, cases treated nonoperatively are reported to do relatively well for many years, despite a high rate of nonunion.168,171 Any hypesthesia, paresthesia, or paralysis in the ulnar nerve distribution is an adequate reason for exploration, inspection of the nerve, and replacement of the fragment. If the ulnar nerve is found to be constricted or contused, it may be transposed anterior to the medial condyle.85,91 This is rarely necessary.153,167

In North America, 2 mm of displacement seems to be a commonly used criterion to determine treatment of physeal fractures in general. If the medial epicondyle is displaced 2 mm or less, the elbow may be immobilized for 3 weeks in a long arm cast, with the elbow in moderate flexion and the forearm in pronation. Oblique roentgenographs or comparison roentgenographs of the normal opposite elbow may be helpful in determining the degree of displacement. If the medial epicondyle is displaced more than 2 mm or rotated, or if the elbow joint is unstable on application of valgus stress, open reduction and internal fixation are indicated. The gravity stress test is a useful diagnostic test for acute medial instability.179 Displaced fractures of the medial epicondyle, if left untreated, frequently progress to malunion or nonunion (Fig. 16-6). Tardy ulnar palsy is a common late problem despite relatively good elbow motion and freedom from symptoms for several years.171 The medial epicondyle can sometimes be reduced by closed means but cannot be held reduced. Percutaneous pinning is hazardous because of the proximity of the ulnar nerve. Therefore, open reduction and internal fixation with two smooth Kirschner wires, one screw, or absorbable rods and screws, is frequently per-

FIGURE 16-6

A 15-year-and-8-month-old boy with tardy ulnar nerve palsy secondary to nonunion of a previous medial epicondyle fracture. Note hypertrophy of the epicondyle but lack of growth of the medial metaphysis.

Chapter 16 Physeal Fractures of the Elbow

formed.168,174,178 It is usually not necessary to mobilize the ulnar nerve, although if the epicondyle is markedly displaced, this maneuver may be helpful in gaining exposure. Kirschner wires should be removed after 3 weeks and active motion begun. Potential complications after pinning, however, include pseudarthrosis, an ulnar sulcus, a double-contoured epicondyle, hypoplasia, or hyperplasia.176 The physis of the epicondyle often closes after fracture, but because it does not contribute to longitudinal length4 and because the epiphysis does not articulate with the ulna, problems due to growth arrest are rare or nonexistent. This is particularly true because most of these children are near maturity and the other physes about the elbow have already closed. Because of the proximity of the ulnar collateral ligament, elbow stability should be examined after fracture healing. Severe chronic medial instability, and even recurrent elbow dislocation, although rare, may occur after fibrous union of a displaced fracture.177,179 Treatment options include osteosynthesis of the fragment to the condyle or excision of the fragment.

LATERAL EPICONDYLE The ossification center of the lateral epicondyle appears at about age 10 years (see Figs. 16-1 and 16-8A) and fuses with the lateral condyle at 14 years of age.2 Its ossification characteristics are prone to misinterpretation as an avulsion or chip fracture of the lateral metaphysis because (1) it ossifies as a smooth, thin, curved sliver of bone; (2) it is well separated from the humerus; and (3) the distal part usually fuses with the capitellum before the proximal part unites with the adjacent humeral shaft. As the epiphysis matures, its outline usually becomes smooth and well defined, but it may be irregular.2 Fracture of the lateral epicondyle is uncommon (see Table 16-1), and is usually associated with other elbow injuries. Separation fracture may accompany elbow dislocation.180 Isolated fracture of the lateral epicondyle is rare.9,65 In most cases, there is relatively little displacement of the fragment. Immobilization of the elbow for 3 to 4 weeks usually is sufficient. Open reduction and internal fixation are usually unnecessary because these injuries tend to occur only in children approaching the age of skeletal maturity. The risk of associated growth arrest is minimal or nonexistent. Tardy ulnar nerve palsy has been reported.91

sphere, ossification soon advances into one or two ovoid, flat, or wedge-shaped nuclei, which may be eccentrically located on the radial metaphysis45 and misinterpreted as an avulsion fracture of the epiphysis. Notches and clefts in the proximal radial metaphysis may closely resemble post-traumatic appearances.3 By definition, radial head fractures in children (age 0 through 16 years) are those that include the physis (Fig. 16-7). If these fractures appear in older children in whom physis is closed, they include the articular surface.18,184 Radial neck fractures are metaphyseal, entirely distal to the physis. Physeal fractures 1, 2, 5, and 6 also involve the metaphysis, but because the major problem is physeal or articular cartilage involvement, they all qualify as fractures of the head. Of all pediatric elbow fractures, 10% to 15% involve the radial head and neck (see Table 16-1).18,191 Of these head and neck fractures, approximately 50% involve the head and 50% the neck (Table 16-6).18 Proximal radial physeal fractures account for only 0.6% of all physeal fractures.18,20 The normal valgus carrying angle of the elbow causes compression laterally during a fall on the outstretched arm. This drives the capitellum against the outer side of the head of the radius, tilting it and displacing it outward. The fracture may be, therefore, type 1, 2, 3, 4, or 5 (see Fig. 16-7), with type 1 being most common (Table 16-7). A second mechanism of injury is associated with posterior dislocation of the elbow with simultaneous compression of the capitellum on the anterior portion of the head of the radius.187 This has the potential to produce the more serious type 4 and 5 fractures. The joint capsule is attached to the radius in continuity with the annular ligament. Because the radial neck lies outside the joint capsule, fracture of the neck may not cause joint effusion or fat pad displacement. Fracture of the radial head, however, usually produces elbow effusion and a positive fat pad sign.3 Fractures of the Proximal Radial Neck and Head in Children*

TABLE 16-6

Open physis

The epiphysis of the radial head begins to ossify at about the age of 5 years. Although it may appear first as a

Radial Neck (Metaphysis)

Radial Head (Physis)

Total

No. (%)

No. (%)

No. (%)

42 (36)

41 (35) †

83 (71)

Closed physis

16 (14)

17 (15)

33 (29)

Total (percent)

58 (50)

58 (50)

116 (100)

*One hundred sixteen fractures, 0 through 16 years.184 All 17 head fractures with closed physes involved the articular surface and were, therefore, similar to type 4 and 5 physeal fractures. From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

†

PROXIMAL RADIUS

257

258

Part IV Conditions Affecting the Child’s Elbow

external immobilization and invariably heal without sequelae. If a type 2 or 3 fracture is minimally displaced or can be manually reduced, immobilization for 3 to 4 weeks will suffice.183 A wire or a hook inserted percutaneously can be used to manipulate a mildly or moderately displaced head into position.9,181 Occasionally, with a type 3 fracture, the entire epiphysis will be inverted or even displaced through the joint capsule, and closed reduction is not possible. In this instance, open reduction is necessary. After surgical reduction, the fracture is often stable, and no internal fixation is necessary.9,189 Immobilization, with the elbow in 90 degrees of flexion and the forearm in neutral rotation, is satisfactory. If the surgical reduction is unstable, internal fixation with two crossed Kirschner wires188 or with one longitudinal wire through the capitellum ossification center extending across the radiocapitellar joint into the intramedullary cavity of the radial diaphysis can be considered.9,186,189 Each method of internal fixation should be supplemented with a long arm cast. The wires may be removed in 3 weeks and gentle protected motion using a collar and cuff begun. If a single longitudinal wire is used, it should be stout enough to avoid wire breakage at the joint level.9 If this occurs, removal of the portion of wire embedded in the radius can be difficult, and it may be less damaging to leave the wire permanently in the radius. Introducing a wire in the distal radius and passing it proximally up the intramedullary canal across the fracture site into the proximal fragment is an appropriate method for reducing or fixing a radial neck fracture, but this procedure is difficult to accomplish in a physeal fracture without further displacing the head. Type 4 and 5 injuries require precise anatomic reduction to restore articular congruity. Open reduction and

Differentiating fractures that involve only the neck of the radius (metaphysis) from those that also involve the physis (head) can be difficult. Oblique roentgenographs and occasionally MRI can be helpful in making this differentiation. The type 1 fracture is common (see Table 16-7), but may be difficult to diagnose. It is usually incorrectly called a neck fracture or type 2 fracture (Fig. 16-8). It is distinguished by a transmetaphyseal fracture with fracture extension to the physis. The transmetaphyseal fracture is often only a compression fracture that may not be visible on the initial roentgenographs. Transmetaphyseal sclerosis, however, is always present 3 to 6 weeks after fracture and verifies the compression component. The fracture line extending to the physis is also frequently difficult to visualize on routine anteroposterior and lateral views and is often best seen on oblique views. This may be only a fracture line, but often there is a displaced corner of metaphysis that may be called a “chip” fracture. Most importantly, however, is that there is no fracture transversely within the physis and the epiphysis is not displaced. Therefore, this is not a type 2 fracture. These fractures need only temporary

Proximal Radius Physeal Fractures by Type (Peterson Classification)22

TABLE 16-7

Type

Year 2000

Author 184

Leung Percent

1

2

3

4

5

6

Total

25 61.0

9 22.0

1 2.4

1 2.4

4 9.8

1 2.4

41 100

From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, with kind permission of Springer Science and Business Media.

M

Figure 16-7

1

2

3

4

5

6

Peterson classification of proximal radius physeal fractures in children. M, metaphyseal (neck) fracture. Fracture types 1 through 6, all of which involve the physis, are fractures of the head because the physis is part of the head. (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

Chapter 16 Physeal Fractures of the Elbow

259

FIGURE 16-8

A, An 11-year-and-6-month-old girl fell down six stairs and noted pain and swelling over the left radial head. Anteroposterior (A), lateral (B), and oblique (C) roentgenographs show a small “chip” fracture of the anterolateral proximal radius metaphysis and very slight increased sclerosis of the proximal neck but no displacement of the epiphysis. A posterior splint was applied. Three weeks after fracture (D), there is increased sclerosis of the proximal radial neck and faint new periosteal bone along the lateral border of the neck. Three months after fracture (E), there is mature subperiosteal new bone along the lateral neck, and the epiphysis and physis are normal. The patient is normally active and asymptomatic, and examination is normal. Note normal lateral epicondyle in A, C, D, and E.

internal fixation with tiny transverse or oblique Kirschner wires will help prevent displacement of the fragments during healing. Premature closure of the physis nearly always occurs,184,187,190 but because the proximal radius accounts for only 20% of the growth of the radius and because type 4 and 5 injuries often occur in older children, problems from growth arrest are rare.182 Functional impairment, however, particularly limited forearm rotation, is common after type 4 and 5 injuries.184 The presence of associated fractures in the humerus and ulna reduces the chance of a favorable outcome.185 Type 6 fracture (a part missing) (see Fig. 16-7) is always an open injury and usually results in functional

impairment.18,21 Regardless of how little physis is lost, the remaining physis always stops growing. Late reconstructive surgery is usually necessary. Most radial head physeal fractures result in premature complete physeal closure and eccentric enlargement of the radial head.185 Abnormal cam motion may occur during forearm rotation, and this may be painful. Excision of the radial head in a growing child will result in distal radial-ulnar length variance and should be avoided. After the patient reaches maturity and has joint pain or limited motion, the radial head may be excised with little risk of development of wrist deformity.85 However, excision of the head rarely restores motion.

260

Part IV Conditions Affecting the Child’s Elbow

Thus, the primary indication for excision of the radial head is pain. The radial head blood supply is through the articular capsular and periosteal vessels. Although these structures are frequently damaged at the time of fracture, ischemic necrosis of the head is uncommon. Treatment considerations relate more to the degree of displacement and angulation, than to the fear of ischemic necrosis.

A

PROXIMAL ULNA The proximal ulnar growth apparatus has features of both an epiphysis and an apophysis.195 Because the proximal ulnar physis produces longitudinal growth and has articular involvement, it is included as an epiphysis. The olecranon is the cartilage/bone projection of the proximal ulna. Its anterior aspect forms the articular surface with the humeral trochlea. As such, the olecranon includes the epiphysis, physis, and most of the metaphysis. Early in life, the physis is L-shaped, extending from the transverse metaphyseal-epiphyseal interface anteriorly and distally as part of the thick subchondral articular surface, to beneath the coracoid process (Fig. 16-9A). With growth, the epiphysis becomes a relatively smaller portion of the olecranon (see Fig. 16-9B, and C). In this sense, the physis “migrates” proximally, and has been called the “wandering physeal line.” The extent of this proximal migration varies among children.47 In the majority of children, the physis continues to migrate proximally and obliquely until it is completely extra-articular (see Fig. 16-9C). This usually occurs by age 12 years. In the minority, the physis remains relatively transverse and closes while its anterior edge is still intra-articular (see Fig. 16-9D). The secondary center of ossification first appears at age 9 years in girls and 11 years in boys.47 The epiphysis initially often has two, sometimes three, and occasionally several ossification centers.5 The physis is usually closed by the end of the 16th year.195 Fractures of the proximal ulna account for 5% to 10% of children’s elbow fractures (see Table 16-1), and are often accompanied by other elbow fractures. Most fractures of the olecranon primarily involve metaphyseal bone distal to the physis (Fig. 16-10M).85 Fractures of the proximal ulnar physis account for only 0.3% of all physeal fractures.18,20 When the physis is involved, the fracture is usually a type 2 injury (see Fig. 16-10, 2a and 2b), occasionally a type 3 injury (see Fig. 16-10, 3). In type 2 injuries, the fracture line in the metaphysis may be oblique (as shown) or may enter the ulnar shaft more longitudinally. Because the proximal fragment contains articular surface, these fractures require ana-

B

C

D

FIGURE 16-9 Proximal ulnar anatomy and growth. A, In infancy the physis is transverse and extends anteriorly and proximally beneath the coracoid. Almost the entire articular surface is part of the epiphysis. B, The ossification center first appears at age 9 years and is separated from the metaphysis more widely than in other epiphyses. The physis is now located relatively closer to the proximal end of the bone. This is called the “wandering physeal line.” The physis still extends anteriorly and distally beneath the entire joint surface. C, By age 12 years, the physis has “migrated” proximally to become entirely extra-articular in most people. In this case, the features of an apophysis now predominate. D, In the minority of individuals, the “migration” ceases while the anterior edge of the physis is still intraarticular. In this case, the features of an epiphysis still predominate. (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

Chapter 16 Physeal Fractures of the Elbow

tomic reduction and maintenance of reduction until the fracture has united. Frequently, this can be accomplished by closed means, immobilizing the elbow in extension. However, if displacement is more than 3 mm, open reduction and internal fixation are advised.193 Fixation may be accomplished by longitudinal Kirschner wire

M

261

or a wire loop, or in older children, a tension band wire. A longitudinal screw should not be used in a young child if significant growth remains.9 However, growth arrest problems are rare.196,199 Excision of the fragment, which is sometimes performed in adults, should be avoided, particularly in young children. In older children, who subject their upper extremities to excessive stress, delayed physeal closure can simulate a nonunion,197,198 sometimes called a stress or chronic type 3 fracture. Fracture of the coronoid apophysis is rare.192 Children with osteogenesis imperfecta are apparently prone to proximal ulnar type 2 anterior fractureavulsions (see Fig. 16-10, 2a). Internal fixation is commonly used, and although fracture union is the rule, refracture can occur.194,199

GROWTH ARREST 1

2a

2b

3

Growth arrest frequently occurs following any elbow physeal fracture. The older the child, the more likely its occurrence. The entire involved physis usually closes. Partial premature closure with resulting angular deformity is rare. Because the elbow physes contribute only 20% of the longitudinal growth of the humerus and forearm, the growth arrest lines that usually occur after any significant bone injury are indistinct at best. Rarely can these lines be used as a measure of growth or as an indication of a growth arrest problem, as they are in other long bones. Because each of the three elbow physes contribute only 10% of the entire upper extremity length, complete closure of any or all of these physes rarely, if ever, causes significant arm length discrepancy. Any resulting discrepancy is mild and causes no functional impairment

FIGURE 16-10 Peterson classification of proximal ulnar physeal fractures in children.22 M, Fracture of the metaphysis. 1, Type 1 fracture with greenstick or longitudinal split fracture. There is a torus or transmetaphyseal fracture with extension of the fracture proximally to the physis. The arrow suggests compression force originates proximally from the epiphyseal side. However, this has not been proven and distally applied pressure could result in compression if the elbow is in full extension at the moment of impact. This fracture has been noted to occur only before ossification of the epiphysis. 2a, Type 2 fracture with anterior metaphyseal fragment. 2b, Type 2 fracture with posterior metaphyseal fragment. 3, Type 3 fracture.38 (From Peterson, H. A.: Epiphyseal Growth Plate Fractures. Heidelberg, Springer, 2007, used with permission of Mayo Foundation for Medical Education and Research.)

262

Part IV Conditions Affecting the Child’s Elbow

and few, if any, cosmetic or clothes-fitting complaints. Even if complete closure of all physes about the elbow occurred in a young child, surgical lengthening of the involved humerus or forearm bones or surgical arrest of the contralateral elbow physes would rarely, if ever, be indicated. Premature partial closure of the distal humerus, or proximal radius or ulna, is very rare. Premature partial closure of the medial or lateral humeral condyle theoretically may result in progressive cubitus varus or valgus, respectively. This could be determined only after many months of follow-up. In this rare occurrence, surgical closure of the remaining physis might be considered. Of 178 bar excisions for premature partial closure performed at Mayo Clinic between 1968 and 1997, none involved the elbow.18 Supracondylar osteotomy to correct angular growth is rarely necessary. Premature closure of the central physis between the medial and lateral humeral condyles occurs occasionally and has been called a fishtail deformity.18,84 The underlying cause of the arrest is multifactorial and may be due to a gap in reduction of an intracondylar fracture, avascular necrosis of the central or trochlear portion of the epiphysis, or central premature physeal arrest (bar formation) without a gap or avascular necrosis. This usually occurs in younger children and causes no pain and only minimal loss of motion. With growth, the deformity can, however, gradually progress to premature degenerative arthrosis and functional disability. The intercondylar notch may also predispose to subsequent intercondylar fracture. Thus, if the fishtail deformity is identified in a young child, surgical closure of the medial and lateral portions of the physis may prevent the deformity from progressing and result in only minimal additional humeral length discrepancy. An occasional concern is damage to the physeal cells between the medial humeral metaphysis and the trochlea in young children. Because the trochlear ossification center has not ossified at this early age, this damage cannot be diagnosed by routine roentgenographs, tomographs, arthrograms, CT scan, or scintigraphy. In the future, MRI may have the ability to evaluate such an injury early. It is often necessary to observe these cases for months or years in order to make the diagnosis of premature partial physeal arrest.

References ANATOMY 1. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the capitellum. J. Bone Joint Surg. 61A:244, 1979. 2. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the lateral epicondyle. J. Bone Joint Surg. 64A:444, 1982.

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humerus in children: fixation with partially threaded 4.0 mm AO cancellous screws. J. Trauma 39:1129, 1995. Shimada, K., Masada, K., Tada, K., and Yamamoto, T.: Osteosynthesis for the treatment of nonunion of the lateral condyle in children. J. Bone Joint Surg. 79A:234, 1997. Skak, S. V., Olsen, S. D., and Smaabrekke, A.: Deformity after fracture of the lateral humeral condyle in children. J. Pediatr. Orthop. 10:142, 2001. Smith, F. J., and Joyce, J. J. III: Fractures of the lateral condyle of the humerus in children. Am. J. Surg. 87:324, 1954. So, Y. C., Fang, D., Leong, J. C. Y., and Bong, S. C.: Varus deformity following lateral humeral condylar fractures in children. J. Pediatr. Orthop. 5:569, 1985. Thomas, D. P., Howard, A. W., Cole, W. G., and Hedden, D. M.: Three weeks of Kirschner wire fixation for diaphyseal lateral condylar fractures of the humerus in children. J. Pediatr. Orthop. 21:565, 2001. Valdisseri, L., Venturi, B., and Busanelli, L.: External humeral condyle fracture in children. A long-term review of 30 cases reported. Chir. Organi. Mov. 78:105, 1993. van Haaren, E. R., van Vugt, A. B., and Bode, P. J.: Posterolateral dislocation of the elbow with concomitant fracture of the lateral humeral condyle: case report. J. Trauma 36:288, 1994. van Vugt, A. B., Severijnen, R. V. S. M., and Festen, C.: Fractures of the lateral humeral condyle in children: late results. Arch. Orthop. Trauma Surg. 107:206, 1988. Vathana, P., and Prosartritha, T.: Repair of nonunion lateral humeral condyle: a case report. J. Med. Assoc. Thai. 81:146, 1998. Wadsworth, T. G.: Injuries of the capitellar (lateral humeral condyle) epiphysis. Clin. Orthop. 85:127, 1972. Wadsworth, T. G.: Premature epiphyseal fusion after injury to the capitellum. J. Bone Joint Surg. 46B:46, 1964.

MEDIAL CONDYLE 148. Bede, W. B., Lefebvre, A. R., and Rosman, M. A.: Fractures of the medial humeral condyle in children. Can. J. Surg. 18:137, 1975. 149. Chacha, P. B.: Fracture of the medial condyle of the humerus with rotational displacement. Report of two cases. J. Bone Joint Surg. 52A:1453, 1970. 150. El Ghawabi, M. H.: Fracture of the medial condyle of the humerus. J. Bone Joint Surg. 57A:677, 1975. 151. Fahey, J. J., and O’Brien, E. T.: Fracture-separation of the medial humeral condyle in a child confused with fracture of the medial epicondyle. J. Bone Joint Surg. 53A:1102, 1971. 152. Fowles, J. V., and Kassab, M. T.: Displaced fractures of the medial humeral condyle in children. J. Bone Joint Surg. 62A:1159, 1980. 153. Kilfoyle, R. M.: Fractures of the medial condyle and epicondyle of the elbow in children. Clin. Orthop. 41:43, 1963. 154. Kim, H. T., Song, M. B., Conjares, J. V., and Yoo, C. I.: Trochlear deformity occurring after distal humeral frac-

tures: magnetic resonance imaging and its natural progression. J. Pediatr. Orthop. 22:188, 2002. 155. Leet, A. I., Young, C., and Hoffer, M. M.: Medial condyle fractures of the humerus in children. J. Pediatr. Orthop. 22:2, 2002. 156. Minami, A., and Sugawara, M.: Humeral trochlear hypoplasia secondary to epiphyseal injury as a cause of ulnar nerve palsy. Clin. Orthop. 228:227, 1988. Ages 10 Years to Maturity 157. Godette, G. A., and Gruel, C. R.: Percutaneous screw fixation of intercondylar fracture of the distal humerus. Orthop. Rev. 22:466, 1993. 158. Kasser, J. R., Richards, K., and Millis, M.: The tricepsdividing approach to open reduction of complex distal humeral fractures in adolescents: a Cybex evaluation of triceps function and motion. J. Pediatr. Orthop. 10:93, 1990. 159. Papavasiliou, V. A., and Beslikas, T. A.: T-Condylar fractures of the distal humeral condyles during childhood: an analysis of six cases. J. Pediatr. Orthop. 6:302, 1986. 160. Peterson, H. A.: Triplane fracture of the distal humeral epiphysis. J. Pediatr. Orthop. 3:81, 1983. 161. Re, P. R., Waters, P. M., and Hresko, T.: T-condylar fractures of the distal humerus in children and adolescents. J. Pediatr Orthop. 19:313, 1999. 162. Royle, S. G., and Burke, D.: Ulnar neuropathy after elbow injury in children. J. Pediatr. Orthop. 10:495, 1990. 163. Saraf, S. K., and Tuli, S. M.: Concomitant medial condyle fracture of the humerus in a childhood posterolateral dislocation of the elbow. J. Orthop. Trauma 3:352, 1989. MEDIAL EPICONDYLE 164. Carlioz, H., and Abols, Y.: Posterior dislocation of the elbow in children. J. Pediatr. Orthop. 4:8, 1981. 165. Case, S. L., and Hennrikus, W. L.: Surgical treatment of displaced medial epicondyle fracture in adolescent athletes. Am. J. Sports Med. 25:682, 1997. 166. Chessare, J. W., Rogers, L. F., White, H., and Tachdjian, M. O.: Injuries of the medial epicondylar ossification center of the humerus. Am. J. Roentgenol. 129:49, 1977. 167. Collins, R., and Lavine, S. A.: Fractures of the medial epicondyle of the humerus with ulnar nerve paralysis. Proc. Child Hosp. DC 20:274, 1964. 168. Dunn, P. S., Ravn, P., Hansen, L. B., and Burph, B.: Osteosynthesis of medial humeral epicondyle fractures in children. 8-Year follow-up of 33 cases. Acta Orthop. Scand. 65:439, 1994. 169. Fowles, J. V., Slimane, N., and Kassab, M. T.: Elbow dislocation with avulsion of the medial humeral epicondyle. J. Bone Joint Surg. 72B:102, 1990. 170. Hendel, D., Aghasi, M., and Halperin, N.: Unusual fracture dislocation of the elbow joint. Arch. Orthop. Trauma Surg. 104:187, 1985. 171. Josefsson, P. O., and Danielson, L. G.: Epicondylar elbow fracture in children. 35-Year follow-up of 56 unreduced cases. Acta Orthop. Scand. 57:313, 1986. 172. Low, B. Y., and Lim, J.: Fracture of humerus during arm wrestling: report of 5 cases. Singapore Med. J. 32:47, 1991.

Chapter 16 Physeal Fractures of the Elbow

173. Ogawa, K., and Ui, M.: Fracture-separation of the medial humeral epicondyle caused by arm wrestling. J. Trauma 41:494, 1996. 174. Partio, E. K., Hirvensalo, E., Bostman, O., and Rokkanen, P.: A prospective controlled trial of the fracture of the humeral medial epicondyle—how to treat? Ann. Chir. Gynaecol. 85:67, 1996. 175. Pritchett, J. W.: Entrapment of the medial nerve after dislocation of the elbow: case report. J. Pediatr. Orthop. 4:752, 1984. 176. Skak, S. V., Grossman, E., and Wagn, P.: Deformity after internal fixation of fracture separation of the medial epicondyle of the humerus. J. Bone Joint Surg. 76B:272, 1994. 177. Sugita, H., Kotani, H., Ueo, T., Miki, T., Senzouku, F., Hara, T., Nagagawa, Y., Sakka, A., Nagagawa, T., and Seki, K.: Recurrent dislocation of the elbow [Japanese]. Nippon Geka Hokan 63:181, 1994. 178. Szymanska, E.: Evaluation of AO kit screw fixation of medial condyle and epicondyle distal humeral epiphyseal fractures in children [Polish]. Ann. Acad. Med. Stetin. 43:239, 1997. 179. Woods, G. W., and Tullos, H. S.: Elbow instability and medial epicondylar fractures. Am. J. Sports 5:23, 1977. LATERAL EPICONDYLE 180. Li, Y. H., and Leong, J. C.: Fractured lateral epicondyle associated with lateral elbow instability. Injury 26:267, 1995. PROXIMAL RADIUS 181. Chotel, F., Sailhan, F., Martin, J., Filipe, G., Pem, R., Garnier, E., and Berard, J.: A specific closed percutaneous technique for reduction of Jeffrey Type II lesion. J. Pediatr. Orthop. B 15:376, 2006. 182. Gaston, S. R., Smith, F. M., and Baab, O. D.: Epiphyseal injuries of the radial head and neck. Am. J. Surg. 85:266, 1953. 183. Jeffery, C. C.: Fractures of the head of the radius in children. J. Bone Joint Surg. 32B:314, 1950. 184. Leung, A. G., and Peterson, H. A.: Fractures of the proximal radial head and neck, with emphasis on those that involve the articular cartilage. J. Pediatr. Orthop. 20:7, 2000. 185. Malmvick, J., Herbertsson, P., Josefsson, P. O., Hasserius, R., Besjakov, J., and Karlsson, M. K.: Fracture of the radial

186.

187. 188.

189. 190.

191.

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head and neck of Mason types II and III during growth: a 14-25 year follow-up. J. Pediatr. Orthop. B 12:63, 2003. McBride, E. E., and Monnet, J. C.: Epiphyseal fractures of the head of the radius in children. Clin. Orthop. 16:264, 1960. O’Brien, P. I.: Fractures involving the proximal radial epiphysis. Clin. Orthop. 41:51, 1965. Osada, D., Tamai, K., Kuramochi, T., and Saotome, K.: Three epiphyseal fractures (distal radius and ulna and proximal radius) and a diaphyseal ulnar fracture in a seven-year-old child’s forearm. J. Orthop. Trauma 15:375, 2001. Payne, J. F., and Earle, J. L.: Fracture dislocation of the proximal radial epiphysis. Minn. Med. 52:479, 1969. Reidy, J. A., and Van Gorder, G. W.: Treatment of displacement of proximal radial epiphysis. J. Bone Joint Surg. 45A:1355, 1963. Sessa, S., Lascombes, P., Prevot, J., and Gagneux, E.: Fractures of the radial head and associated elbow injuries in children. J. Pediatr. Orthop. 5:200, 1996.

PROXIMAL ULNA 192. Bracq, H.: Fracture of the coronoid apophysis. Rev. Chir. Orthop. 73:472, 1987. 193. Burrel, C. G., Strecker, W. B., and Schoenecker, P. L.: Surgical treatment of displaced olecranon fractures in children. J. Pediatr. Orthop. 17:321, 1997. 194. Gwynne-Jones, D. P.: Displaced olecranon apophyseal fractures in children with osteogenesis imperfecta. J. Pediatr. Orthop. 25:154, 2005. 195. Parson, F. G.: Observations on traction epiphyses. J. Anat. Physiol. 38:248, 1904. 196. Rabinovich, A., Adili, A., and Mah, J.: Outcomes of intramedullary nail fixation through the olecranon apophysis in skeletally immature forearm fractures. J. Pediatr. Orthop. 25:565, 2005. 197. Retrum, R. K., Wepfer, J. F., Olsen, D. W., and Laney, W. H.: Case report 355: delayed closure of the right olecranon epiphysis in a right-handed, tournament-class tennis player (post-traumatic). Skeletal Radiol. 15:185, 1986. 198. Schweitzer, G.: Bilateral avulsion fractures of the olecranon apophyses. Arch. Orthop. Trauma Surg. 107:181, 1988. 199. Zionts, L. E., and Moon, C. N.: Olecranon apophysis fractures in children with osteogenesis imperfecta revisited. J. Pediatr. Orthop. 22:745, 2002.

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CHAPTER

17

Fractures of the Neck of the Radius in Children Anthony A. Stans

INTRODUCTION Fractures of the neck and head of the radius in children are relatively uncommon, constituting 4% to 7% of elbow fractures and dislocations.2,6,14,16,21,24 A review of the early literature reveals considerable controversy on the significance, treatment, and late results of this injury.12,23,24 However, as is explained in the body of this chapter, since the last edition of this text there has been a growing body of evidence indicating that open reduction and internal fixation should be avoided whenever possible, and that percutaneous reduction (and fixation if necessary) is much more likely to result in a favorable outcome. Sex frequency varies from series to series, but overall, there seems to be a slight female preponderance. The typical patient age range for radial neck fractures is between 4 and 14 years, with a mean age between 10 and 12 years. Approximately 30% to 50% of patients have associated injuries to the elbow region (Figs. 17-1 and 17-2).10,18,32,39 The prognosis after this fracture seems to depend more on the severity of the injury, the associated injuries about the elbow, and the type of treatment than on the accuracy of the reduction.10,16,23,25 Although emphasis has been placed on the angulation of the radial head, it is actually the displacement of the fracture that is the more important component of the deformity. The classic discussion on this subject was published by Jeffery,10 whose observations in 1950 clarified the nature of the fracture, the mechanism of injury, the radiologic assessment, the method of reduction, and the prognosis. Complete remodeling of a fracture was demonstrated with perfect function after a residual angulation of 50 degrees. Closed reduction consistently produces better results than open reduction, even taking into account that more severe injuries are more likely to require operation.23,25 Recently, significant technical advances

have been made, making possible the percutaneous reduction of even severely displaced or angulated fractures.1,8,20,31,34

MECHANISM OF THE FRACTURE A fall on the outstretched arm produces a valgus thrust on the elbow that fractures the radial neck and often avulses structures on the medial side of the joint. The radial head tilts laterally because the forearm is usually supinated, but the exact direction of the tilt depends on the rotational position of the forearm at impact. This is the most common mechanism, but the fracture can also occur with posterior dislocation of the elbow, resulting in two types of displacement, depending on whether the radial head fractures during spontaneous reduction or in the course of dislocating. The first type of fracture10,11 (reduction injury) leaves the separated proximal radial epiphysis tilted 90 degrees posteriorly beneath the capitellum of the humerus (Figs. 17-3 and 17-4). This mechanism of injury has been confirmed in a report of an iatrogenic radial neck fracture that occurred during closed reduction of a posterior elbow dislocation.36 With the second type of fracture23 (dislocation injury), axial compression on the elbow results in anterior displacement of the radial head as the proximal radial epiphysis moving posteriorly is obstructed by the capitellum and fractures in the process (see Fig. 17-2). Less common injuries include anterior dislocation of the head of the radius with associated fracture of the radial neck; Montaggia equilavent injuries28; shear fracture through the neck of the radius with medial displacement of the shaft, which may become locked medial to the coronoid process of the ulna17; and osteochondral fracture of the epiphysis with an intra-articular loose body. Associated injuries occasionally occurring with radial neck fracture include fracture of the olecranon, avulsion of the medial epicondyle of the humerus, dislocation of the elbow, and avulsion of the medial collateral ligament from the distal humerus.10 Associated injuries are not only important in themselves but also have implications for prognosis and treatment of the radial neck fracture (see Figs. 17-1 and 17-2).16,39

CLASSIFICATION The fracture may be classified by the degree of angulation of the radial head,24,26 the mechanism of injury,10 the type of epiphyseal plate disruption,26,29 the amount of fracture displacement, or combinations of these.23 O’Brien24 divided these fractures into three groups according to the degree of angulation:

Chapter 17 Fractures of the Neck of the Radius in Children

A

B

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the shaft (see Chapter 2). The radius is not a straight bone, even in its proximal third.16,33 Thus, a measured angulation of 50 degrees may in reality represent only 35 to 40 degrees of true angulation. As in many pediatric injuries, comparison with the uninjured elbow is often helpful, or even essential, for accurate assessment of this feature. The injury also may be classified according to the type of epiphyseal plate injury. Although some authors believe that the fracture may occur entirely through the metaphysis of the neck of the radius,12,38 this is unusual, both in the literature23 and in our experience.39 The pattern of proximal radial physeal injuries, as traditionally classified by Salter and Harris, includes the following types: Type I: Rare and usually associated with dislocation of the radial head or elbow Type II: The most common pattern of fracture through the neck of the radius Type III: Rare Type IV: Second in frequency39 and associated with a poor prognosis owing to marked displacement, irregularity of the radial head, and occasional radioulnar synostosis (Figs. 17-5 and 17-6) We prefer the classification of Wilkins,27 which combines those of Jeffery10 and Newman.23 It is based primarily on the mechanism of injury, but it also describes the deformity to be corrected and suggests the severity of the injury and thus helps in formulating the prognosis.

C

FIGURE 17-1

A, A displaced and angulated fracture of the neck of the radius and fracture of the olecranon (arrow) in an 8-year-old girl. B, Three weeks after closed reduction and immobilization, it is apparent that the capsular attachment has avulsed a portion of the medial epicondyle (arrow). C, Three years later, the patient had perfect function and no pain.

Type I: less than 30 degrees Type II: 30 to 60 degrees Type III: More than 60 degrees

I. Valgus fractures A. Type A: Salter-Harris type I and II injuries of the proximal physis B. Type B: Salter-Harris type III and IV injuries of the proximal radial physis C. Type C: Fractures involving only the proximal radial metaphysis II. Fractures associated with dislocation of the elbow A. Type D: Reduction injuries B. Type E: Dislocation injuries We have added Salter-Harris type III fractures to the type B classification. These may produce an intraarticular loose body consisting of articular cartilage and a portion of the epiphysis.

TREATMENT He also described an impaction fracture of the articular surface of the head, an injury that is more likely to be associated with lesser degrees of angulation. It is important to recognize that the neck of the radius normally subtends an angle of 165 to 170 degrees with

ASSESSMENT OF INJURY The entire extremity should be thoroughly examined for open wounds, other injuries, and neurovascular

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B

FIGURE 17-2

A, An open dislocation of the elbow, fracture of the neck of the radius, and badly displaced fractures of the distal radius and ulna in a 10-year-old girl. Definitive treatment was not rendered until 8 days after the injury. Two years later (B and C), there was synostosis of the radius and ulna and enlargement and irregularity of the head of the radius.

A

C

A FIGURE 17-3

B

A, Radiograph of the elbow of an 8-year-old girl who had fallen 6 weeks earlier. The radial head is tilted 90 degrees posteriorly and is not articulating with the joint surface of the capitellum. The presumed mechanism of this fracture pattern is that (spontaneous or manipulative) reduction of a posteriorly dislocated elbow reduces the dislocation but leaves the radial head displaced. B, In the same patient 22 years after open reduction, note the enlargement and irregularity of the radial head. She had a full range of motion and no pain. This is the only exception in our experience to the rule that stiffness usually follows late open reduction.

Chapter 17 Fractures of the Neck of the Radius in Children

271

A(2)

A(1)

B

C(1)

C(2)

impairment. A fall on the outstretched hand can result in injury at multiple levels. As in adults, injury about the wrist must be specifically excluded, and fracture of the scaphoid has been reported.10,11 Anteroposterior and lateral radiographs of both the elbow and the entire forearm should be examined for other injuries, particularly about the elbow. An estimate should also be made of the degree of angulation of the radial head and the amount of displacement. The precise degree of angulation can be accurately determined only by an anteroposterior radiograph with the forearm in the position of rotation at the moment of impact. Jeffery10 demonstrated that this is best achieved by taking radiographs in varying degrees of forearm rotation so that the radial head will cast shadows of different shapes. When the radial head forms as nearly

FIGURE 17-4 A, Fracture of the neck of the radius in a 13-year-old girl with dislocation of the elbow and marked posterior angulation was treated (B) by open reduction and internal fixation with a wire passed through the capitellum into the radius. The high rate of complications associated with this method of fixation makes it an undesirable method of treatment. C, Three years later, there is deformity of the head of the radius, subluxation, and marked restriction of forearm rotation.

perfect a rectangle as possible, the real degree of angulation can be determined. Oval shapes indicate that the radiographs have not been taken at a right angle to the plane of maximal angulation (Fig. 17-7). Although obtaining these multiple views is not practical or necessary for the majority of fractures, in cases in which it is unclear whether or not fracture reduction is indicated, performing multiple radiographs as described can be very helpful. Comparison views of the uninjured forearm in the same degree of rotation are helpful in assessing the degree of angulation. Also, in children, normal variations in the radiographic appearance of the proximal radius must be considered when assessing injury.30 Again it is a basic principle of treating elbow fractures in children that radiographs of the injury may be compared with films of the opposite (uninjured) side.

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A(2)

A(1)

A(3) 7 yrs

Post injury

FIGURE 17-5

A, A type IV fracture of the radial head and a dislocation of the elbow in an 8-year-old boy. B, The free fragment was excised, along with the radial head (left). Seven years later (right), that patient had very little forearm rotation, limited extension, irregularity of the articular surface, and valgus deformity.

B

FIGURE 17-6

A

B

A, A comminuted fracture of the head of the radius in a 13-year-old boy. Note the free fragment, which consisted of epiphysis, growth plate, and metaphysis, on the medial aspect of the ulna. The radial neck fracture was reduced open and the fragment was excised. B, Four years later, the patient had full flexion, extension, and pronation but no supination. Note the defect on the medial aspect of the head of the radius. The elbow was only occasionally painful.

Chapter 17 Fractures of the Neck of the Radius in Children

A

E

a

b

c

d

e

FIGURE 17-7

Diagram of the radiographic appearance of the head of the radius in varying degrees of rotation, where A = a and E = e. When the film is taken at right angles to the plane of maximum angulation, the radial head is rectangular in shape as in Ee (shaded epiphysis).

INDICATIONS FOR REDUCTION It is generally agreed that a radial neck fracture with angulation of more than 60 degrees or more than 3 mm of displacement will likely produce problems if it is not corrected.2,6,23,24,39 It is also agreed that in radial neck fractures, less than 30 degrees’ angulation can safely be accepted,10,25,33 and there is some support for the position that fractures less than 45 degrees’ angulation do not require open reduction.2,23,24,32,35,39 The proper treatment approach should be individualized based on the clinical circumstances of each patient when angulation is between 30 and 60 degrees. There is support both for and against open reduction of these fractures.6,18,25,26,32,39 Advocates of open reduction believe that, without it, significant loss of forearm rotation will ensue. Those who prefer closed reduction or acceptance of deformity believe that the complications of open reduction do not justify the risks, considering the minimal disability that is the legacy of fractures left with even 50 to 55 degrees of angulation. Recently, two techniques have been developed that provide the benefits of improved fracture alignment yet have not caused the problems associated with open reduction. In several series, percutaneous reduction of radial neck fractures has been associated with fewer complications and less elbow stiffness as compared with open reduction (Fig. 17-8).1,20,31 Originally described using

273

a Steinmann pin, we have also used a small elevator to percutaneously reduce the fracture with excellent success. After percutaneous reduction, fracture stability should be assessed by bringing the elbow through full range of motion including pronation and supination under fluoroscopic imaging. Frequently, the fracture is stable enough that internal fixation is not necessary and casting alone is sufficient. In situations in which redisplacement or angulation occurs, percutaneous pinning or intramedullary stabilization using the Metaizeau technique may be employed. Metaizeau and colleagues20 described a method of reducing and stabilizing displaced or angulated radial neck fractures using an intramedullary K-wire. An intramedullary pin or small-diameter flexible intramedullary nail is used to enter the radius in a retrograde fashion just proximal to the distal radial physis. Before insertion, a 30- to 45-degree bend is placed in the pin approximately 1 cm from the tip. Advancing the intramedullary pin proximally to the fracture site, the intramedullary pin is used to elevate the depressed or angulated fracture (Fig. 17-9). Rotation of the bent tip is then used to correct displacement. The intramedullary pin is cut proximally where it lies beneath the skin, along the surface of the radius. Often, the pin becomes symptomatic at the insertion site and may be removed after the fracture has completely healed, 3 to 9 months following surgery. Occasionally, radial neck fractures cannot be reduced by use of an intramedullary pin alone. Employment of an intramedullary pin in combination with percutaneous reduction techniques described earlier is a very effective means of reducing and stabilizing severely displaced or angulated fractures by minimally invasive methods. Percutaneous and intramedullary reduction and fixation techniques represent a significant advance in the treatment of radial neck fractures, providing the benefits of improved fracture reduction with minimal risk of avascular necrosis (AVN) and stiffness associated with open techniques.8,20 Displacement, rather than angulation, often leads to loss of forearm rotation. Angulation produces a defect at the joint surface and, therefore, does not obstruct rotation. Incomplete contact between articular surfaces is, theoretically, harmful, but enough remodeling usually occurs so that the incomplete contact appears to improve. Displacement, on the other hand, results in radial neck deformity and abutment on the edges of the radial notch (Fig. 17-10). This produces a cam effect during rotation, confirmed in cadaver studies.39 The radial neck was divided with a saw and fixed with Kirschner wires without angulation but with varying degrees of displacement. The observed effect on forearm rotation was that displacement greater than 3 mm resulted in loss of forearm rotation because of abutment of the radial head against the ulna.

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A

B

FIGURE 17-8

C

D

Because closed or open reduction performed more than 5 to 7 days after injury leads to loss of forearm rotation and radioulnar synostosis,18,23,32,39 a fracture more than 1 week old is a relative contraindication to reduction. It is better to accept deformity.

PRINCIPLES OF TREATMENT Review of the literature indicates that, regardless of the severity of the injury, closed treatment gives better results than open treatment. In addition, fractures treated with internal fixation tend to have poor results compared with those treated without internal fixation. In particular, transcapitellar fixation with a Kirschner wire passed through the capitellum of the humerus and across the joint into the head and medullary canal of the radius is

A, Fracture of the radial neck angulated approximately 45 degrees. B, A Steinmann pin is inserted percutaneously. C, Using fluoroscopic guidance, the Steinmann pin is used to reduce the fracture. D, Normal anatomy is restored without open reduction, and the fracture is stable without internal fixation. (From Green N. E., and Swiontkowski, M. F.: Skeletal Trauma in Children, 2nd ed. Philadelphia, W. B. Saunders, 1998.)

associated with significant complications including septic arthritis, breakage of the wire within the joint, and nonunion (see Figs. 17-4 and 17-11).7,19 Thus, as little internal fixation as possible is recommended.2,39 When necessary, intramedullary fixaton using the Metaizeau technique seems to avoid the undesirable consequences associated with other internal fixation techniques. Finally, immobilization of the elbow for more than 3 to 4 weeks leads to stiffness, even in children. Thus, the following principles apply to treating radial neck fractures: 1. Closed treatment generally gives better results than open reduction. 2. If closed treatment is not acceptable, use percutaneous reduction and fixation technique.

Chapter 17 Fractures of the Neck of the Radius in Children

C

A D

B E FIGURE 17-9 A, Radial neck fracture angulated greater than 45 degrees. B, A 2-mm diameter pin with a slight bend 1 cm from the tip is advanced retrograde to the fracture within the intramedullary canal and used to elevate the depressed and angulated fracture. C, Rotating the intramedullary pin reduces fracture displacement. D, One year postoperatively, immediately before hardware removal, the fracture has completely healed with full elbow motion in all planes E.

275

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Part IV Conditions Affecting the Child’s Elbow

3. When internal fixation is necessary, use intramedullary technique whenever possible. 4. Treat promptly. 5. Do not use transcapitellar wires. 6. Do not immobilize the fracture longer than 4 weeks.

FIGURE 17-10 Diagram illustrates the effect of union with displacement of the fracture. The white circle represents the shaft of the radius just distal to the fracture, and the gray circle represents the head of the radius. The black area represents the radial notch on the ulna. Rotation of the radius after union with persistent displacement results in abutment on the margin of the radial notch of the ulna. The degree of limitation of pronation and supination is proportional to the degree of displacement.

4 yrs. Post injury

RESULTS When assessing the published results of radial neck fractures, it is apparent that pain from this injury is seldom disabling.9,21,32,35,39 Unsatisfactory results consistently are based on the degree of restriction of elbow and forearm motion.6,7,10,23,26 It may be that permanent stiffness develops, not only because of a mechanical block to rotation but also, possibly, because of reflex inhibition to avoid a painful arc of motion. Even when irregularity of the joint surface results in stiffness, there is usually surprisingly little pain. On the other hand, a “successful” open reduction with a perfect anatomic result also may be associated with significant loss of forearm rotation. Series of patients followed as long as 22 years confirms this impression: Pain is not a prominent feature and is not the reason for poor results.39 Loss of 20 degrees of supination or as much as 40 degrees of pronation is not disabling, particularly when it occurs at a young age. “Fair” and “poor” results occur when loss of forearm rotation is greater than 40 degrees. In contrast to the legacy of adults’ radial neck fractures, loss of elbow flexion and extension is less common in children and not as disabling as loss of rotation. When a limitation develops, it is usually extension that is lost and then seldom more than 30 to 35 degrees. AVN of the radial head, radioulnar synostosis,1,18,23,39 and removal of the radial head are associated with poor results.1,22,35 The incidences of radioulnar synostosis and AVN of a substantial portion of the head of the radius are difficult to determine because of the small series of

FIGURE 17-11 Nonunion of the neck of the radius 4 years after open reduction and fixation with a transcapitellar wire in a 12-year-old boy.

Chapter 17 Fractures of the Neck of the Radius in Children

fractures of the neck of the radius in children. The problem is further complicated by the fact that these complications are associated with widely displaced fractures, those treated overenthusiastically, those treated late, and those concomitant with dislocations of the elbow. These injuries, in turn, make up a smaller part of the total number of fractures. It is enough to say that, in almost every reported series, these complications are mentioned. AVN and synostosis complicate 5% to 20% of fractures and usually follow open reduction and fixation. The unanticipated good results subsequent to acceptance of considerable deformity is related to remodeling of the deformity.4,9,10,18 This is surprising, because the plane of the fracture lies at right angles to the plane of motion of both the elbow and the radioulnar joints. This would seem to be an exception to the rule that remodeling in the child can be expected only if the fracture deformity is in the same plane of motion as the nearby joint. This remodeling may explain why younger children do better after fracturing of the neck of the radius than do older children. Premature fusion of the proximal radial epiphysis does occasionally occur, but it does not appear to influence the final result.23,24 It does not lead to significant shortening of the radius nor to valgus deformity at the elbow.10,23 This is because most of the growth occurs at the distal end, and, initially, the fracture stimulates distal radius growth. Thus, the result depends largely on the degree of restriction of motion. Composite loss of pronation, supination, flexion, and extension greater than 90 degrees leads to functional disability and a poor result. Results are directly related to the severity of the injury, concomitant injuries about the elbow, and how much physical intrusion is necessary to reduce the fracture.7,9

COMPLICATIONS COMPLICATIONS RELATED TO THE INJURY Radioulnar Synostosis The dreaded complication of radioulnar synostosis (see Fig. 17-2)1,18,23,24,25,39 is associated with widely displaced fractures and is often associated with dislocation of the elbow.

Premature fusion is common but of little consequence.4,9,10,18,26

Premature Fusion of the Epiphyseal Plate

277

effect is determined by the degree of loss of blood supply. Enlargement of the Head of the Neck of the Radius and Increase in Diameter of the Neck of the Radius This complication, which is often seen, is accom-

panied by compensatory enlargement of the capitellum of the humerus.23,24,26 Because growth is stimulated by the increased vascularity during the healing phase, the event is of little significance. Ectopic Calcification Ectopic calcification is also frequent, but it is usually limited and has little effect on the outcome.23,25,26,33,39 Vascular and Peripheral Nerve Injury Injuries to vessels and to peripheral nerves are unusual after this injury. When vascular injury occurs, it is usually related to dislocation of the elbow. Nerve injury may occur, but permanent paralysis is unusual. Impaction or Shear Injury to the Articular Surface of the Radial Head This complication is difficult to diag-

nose because it occurs in fractures that produce less angulation and because the joint injury is not directly visualized,24 but it can lead to elbow stiffness and premature physeal closure. A shear injury to the head of the radius can produce an intra-articular free osteochondral fragment containing articular cartilage and a “variable amount” of epiphysis.

COMPLICATIONS RELATED TO TREATMENT Avascular Necrosis AVN can complicate not only widely displaced fractures but also those with lesser degrees of displacement treated by open reduction (see Fig. 17-12).12,16,18,23,39 The risk of AVN can be reduced by carefully preserving the soft tissue attachments. It is seldom seen with closed treatment. Radioulnar Synostosis Radioulnar synostosis also may result from less severe injuries that have undergone the trauma of open reduction or late closed reduction (see Fig. 17-2).3,10 If complete dislocation of the radial head or a dislocation of the elbow is initially unrecognized, reduction should probably be attempted up to 3 months after the injury (see Fig. 17-3). In this setting, the parents must be warned that significant stiffness will result.

Postoperative infection39 is always a concern with open procedures and can result in dissolution of the articular surface and ankylosis.

Infection Avascular Necrosis AVN is most common (Fig. 17-12)12,18,23,32,39 after open reduction but can occur with widely displaced fractures treated by closed reduction. Although this complication probably occurs to a certain extent in many of these serious injuries, the eventual

Nonunion is rare, but when it occurs, it is almost always after open reduction (see Fig. 17-11).37

Nonunion

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Part IV Conditions Affecting the Child’s Elbow

B

A

D

C FIGURE 17-12 A, Irreducible fracture angulated 90 degrees. B, Open reduction was performed with two K-wires place at the periphery of the articular surface angled obliquely across the fracture site. C and D, Three years postoperatively, the patient shows signs of avascular necrosis, but the fracture has united and the patient has excellent motion in all planes.

Chapter 17 Fractures of the Neck of the Radius in Children

Poor results are inevitable,4,26,39 but there may be surprisingly little pain, and excision should be deferred until skeletal maturity. Bone grafting should be considered with caution because radioulnar synostosis frequently develops. Healing of the nonunion has not necessarily led to improvement of clinical symptoms. A rare cause of nonunion may be complete reversal of the head of the radius when the fracture surface faces the capitellum of the humerus and the articular surface faces the distal fragment.25 The radial head should be returned to its proper orientation, even if it has lost all its soft tissue attachments. It should not be excised. Damage to the Articular Surface Such damage can result from injury or from breakage of wires inserted across the joint to fix the fracture. This technique also is associated with stiffness, so it should be avoided.

Stiffness has been associated with open treatment, internal fixation, delayed treatment more than 1 week after the injury, and immobilization longer than 4 weeks.

Loss of Motion

AUTHOR’S PREFERRED METHOD OF TREATMENT Selection of the treatment technique depends on the nature of the injury. The sequence and method of treatment preferred by the author is based on his personal zeal for treating these injuries “closed” whenever that is at all possible. 1. Angulation of less than 45 degrees and displacement of less than 3 mm. An above-elbow cast with the elbow flexed 90 degrees and the forearm in neutral rotation for 3 weeks is appropriate (Fig. 17-13). Radiographs should be taken after 4 to 7 days to check the position. After immobilization is discontinued, the patient may gradually resume normal activity. Physiotherapy is not necessary, and patients may be instructed on simple gentle active stretching exercises. The child should be seen in 3 weeks and again in 3 months, by which time full range of motion should have returned. 2. Angulation between 45 and 60 degrees with displacement of less than 3 mm. Gentle closed reduction by the method described later should be attempted. If the reduction cannot be improved by closed means, percutaneous reduction should be considered. However, if percutaneous reduction proves unsuccessful, the deformity should be accepted. 3. Angulation greater than 60 degrees and displacement of more than 3 mm. Every possible attempt should be made to reduce the fracture

279

closed. It is, however, equally important to be gentle in all attempts. With the patient under general anesthesia, the forearm is rotated while the operator palpates for the position of maximal prominence of the head of the radius at different degrees of flexion and pronation/supination. An assistant applies varus stress to the elbow to open the joint laterally and to increase the prominence of the radial head. Firm pressure is applied to the radial head in mediad and craniad directions. Successful reduction is confirmed by radiographs (several views may be necessary). If the elbow region is too swollen to palpate the radial head, an assistant should stabilize the humerus and flex the elbow to 90 degrees. The forearm is rotated to full supination without applying varus strain to the elbow. Thumb pressure is applied to the anterolateral aspect of the head of the radius just lateral and distal to the cubital fossa. At the same time, the forearm is gradually rotated to the neutral position and then into full pronation. A variation on this technique has been recently described by Neher.22 The reduction is verified radiographically, preferably with a C-arm fluoroscope. The patient’s arm is placed in an above-elbow splint or cast for 3 weeks, and a follow-up radiograph is taken after 1 week.13 If this maneuver fails to achieve reduction, an Esmarch bandage is wrapped snugly around the elbow and the radiographic studies are repeated. Occasionally, this results in reduction. If reduction is still inadequate, the arm is prepared and draped, and an attempt is made to achieve a percutaneous reduction.1,5,31,34 Under fluoroscopic control, a Steinmann pin or small elevator is introduced through the skin, and the radial head is pushed into proper position (see Fig. 17-8). If reduction is achieved and is stable, with the elbow flexed 90 degrees and the forearm in a natural position, a long arm cast is applied. Radiographs confirm the maintenance of reduction. If the radial neck fracture reduction cannot be achieved, cannot be maintained, or is unstable, then an intramedullary pin is placed using the Metaizeau technique (see Fig. 17-9). Only in the rare situation in which percutaneous reduction and the Metaizeau technique are not successful should open reduction be performed. A 5-cm incision is made, commencing on the lateral aspect of the capitellum and angling posteriorly over the radial head. This is the central portion of Kocher’s posterolateral incision at the interval between the extensor carpi ulnaris and the anconeus muscles. To avoid damaging the posterior interosseous nerve, no incision should be made distal to the bicipital tuberosity of the radius. The elbow joint is entered anterior to the anconeus muscle. Do not interfere with the orbicular ligament even if torn, or stiffness may result. The radial head is reduced into its

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Part IV Conditions Affecting the Child’s Elbow

A

B

D C FIGURE 17-13 A and B, The author’s daughter fell from a couch, sustaining this radial neck fracture angulated 40 degrees, and an associated, nondisplaced olecranon fracture. C and D, Two years following cast immobilization without reduction, the fracture alignment has completely remodeled and the patient has full motion in all planes with unlimited function.

proper position and is often sufficiently stable to make internal fixation unnecessary. If the radial head is unstable, the child’s bone is often soft enough to allow use of a heavy absorbable suture on a stout cutting needle to hold it in place, introducing the needle at the articular margin of the radial head and passing it across the fracture into the neck of the radius and through the cortex. If this does not seem feasible, one or two fine, smooth Kirschner wires are inserted at the articular margin of the radial head, across the fracture, and just through the cortex of the radial neck (see Fig. 17-12). They should be bent external to the skin, cut external to the skin, and a dressing sponge or gauze placed beneath the pins to facilitate removal in 3 weeks. A growing child’s radial head must never be excised. Excision results in pain, increased carrying angle, radio-

ulnar synostosis, or distal radioulnar dysfunction (see Fig. 17-5).2,3,15 If stable reduction cannot be achieved, less than optimal reduction should be accepted. Delayed radial head resection is not usually necessary but can be performed at skeletal maturity. The rare Salter-Harris type III or IV injury produces a dilemma. The fracture fragment should be fixed whenever possible, but if the fragment is too small, the fragment should be excised. The prognosis for Salter-Harris type III or IV fractures is guarded. Loss of motion after this fracture may be due to other factors, because the injury is usually produced by considerable forces. Immobilization following open reduction is as described for closed treatment and should be continued for no more than 3 to 4 weeks. If Kirschner wires have been used, they should be removed at this time. Reha-

Chapter 17 Fractures of the Neck of the Radius in Children

bilitation and follow-up are exactly as described for closed treatment.

SUMMARY Fracture of the neck of the radius is a rare but serious injury, particularly when it is associated with marked angulation and displacement or with concomitant injuries to the elbow region. Every possible attempt should be made to treat this injury closed. Even though more serious fractures are treated by open reduction, clinical reports and personal experience suggest that surgical intervention has an adverse effect on the outcome. Percutaneous reduction techniques may permit reduction of more serious fractures without open surgical exposure. When open reduction is necessary, dissection and internal fixation should be kept to a minimum. Treatment later than 1 week after the injury leads to stiffness, as does external immobilization for longer than 4 weeks.

Acknowledgment The author would like to recognize Dr. John H. Wedge. The current chapter is based on the extensive work done by Dr. Wedge as author of this chapter in previous editions of The Elbow and Its Disorders.

References 1. Bernstein, S. M., McKeever, P., and Bernstein, L.: Percutaneous reduction of displaced radial neck fractures in children. J. Pediatr. Orthop. 13:85, 1993. 2. Blount, W. P.: Fractures in Children. Baltimore, Williams & Wilkins, 1955, p. 56. 3. Bohrer, J. V.: Fractures of the head and neck of the radius. Ann. Surg. 97:204, 1933. 4. Conn, J., and Wade, P. A.: Injuries of the elbow. A ten year review. J. Trauma 1:248, 1961. 5. Dormans, J. P., and Rang, M.: Fractures of the olecranon and radial neck in children. Orthop. Clin. North Am. 21:257, 1990. 6. Dougall, A. J.: Severe fracture of the neck of the radius in children. J. R. Coll. Surg. Edinb. 14:220, 1969. 7. Fowles, J. V., and Kassab, M. T.: Observations concerning radial neck fractures in children. J. Pediatr. Orthop. 6:51, 1986. 8. González-Herranz, P., Alvarez-Romera, A., Burgos, J., Rapariz, J. M., and Hevia, E.: Displaced radial neck fractures in children treated by closed intramedullary pinning (Metaizeau technique). J. Pediatr. Orthop. 17:325-331, 1997. 9. Henriksen, B.: Isolated fractures of the proximal end of the radius in children. Epidemiology, treatment and prognosis. Acta Orthop. Scand. 40:246, 1969.

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10. Jeffery, C. C.: Fractures of the radius in children. J. Bone Joint Surg. 32B:314, 1950. 11. Jeffery, C. C.: Fractures of the neck of the radius in children. Mechanism of causation. J. Bone Joint Surg. 54B:717, 1972. 12. Jones, E. R. L., and Esch, M.: Displaced fractures of the neck of the radius in children. J. Bone Joint Surg. 53B:429, 1971. 13. Kaufman, B., Rinott, M. G., and Tangman, M.: Closed reduction of fractures of the proximal radius in children. J. Bone Joint Surg. 71B:66, 1989. 14. Landin, L. A., and Danielsson, L. G.: Elbow fractures in children. An epidemiological analysis of 589 cases. Acta Orthop. Scand. 57:309, 1986. 15. Lewis, R. W., and Thibodeau, A. A.: Deformity of the wrist following resection of the radial head. Surg. Gynecol. Obstet. 64:1079, 1937. 16. Lindham, S., and Hugosson, C.: The significance of associated lesions including dislocation in fractures of the neck of the radius in children. Acta Orthop. Scand. 50:79, 1979. 17. Manoli, A.: Medial displacement of the shaft of the radius with a fracture of the radial neck. Report of a case. J. Bone Joint Surg. 61A:788, 1979. 18. McBride, E. D., and Monnet, J. C.: Epiphyseal fractures of the head of the radius in children. Clin. Orthop. 16:264, 1960. 19. Merchan, E. C. R.: Displaced fractures of the head and neck of the radius in children: open reduction and temporary transarticular internal fixation. Orthopedics 14:697, 1991. 20. Metaizeau, J.-P., Lascombes, P., Lemelle, J.-L., Finlayson, D., and Prevot, J.: Reduction and fixation of displaced radial neck fractures by closed intramedullary pinning. J. Pediatr. Orthop. 13:355, 1993. 21. Murray, R. C.: Fractures of the head and neck of the radius. Br. J. Surg. 9:114, 1977. 22. Neher, C. G., and Torch, M. A.: New reduction technique for severely displaced pediatric radial neck fractures. J. Ped. Orthop. 23:626, 2003. 23. Newman, J. H.: Displaced radial neck fractures in children. Injury 9:114, 1977. 24. O’Brien, P. I.: Injuries involving the proximal radial epiphysis. Clin. Orthop. 41:51, 1965. 25. Rang, M.: Children’s Fractures. Philadelphia, J. B. Lippincott Co., 1974, p. 112. 26. Reidy, J. A., and Van Gorder, G. W.: Treatment of displacement of the proximal radial epiphysis. J. Bone Joint Surg. 45A:1355, 1963. 27. Rockwood, C. A., Jr., Wilkins, K. E., and King, R. E. (eds.): Fractures in Children, Vol. 3. Philadelphia, J. B. Lippincott Co., 1984, p. 510. 28. Ruchelsman, D. E., Klugman, J. A., Madan, S. S., and Chorney, G. S.: Anterior dislocation of the radial head with fracures of the olecranon and raidal neck in a young child: A Monteggia equivalent fracture-dislocation variant. J. Orthop. Trauma 19:425, 2005. 29. Salter, R. B., and Harris, W. R.: Injuries involving the epiphyseal plate. J. Bone Joint Surg. 45A:587, 1963. 30. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the radial neck and head. J. Bone Joint Surg. 64A:1153, 1982.

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31. Steele, J. A., and Kerr Graham, H.: Angulated radial neck fractures in children. A prospective study of percutaneous reduction. J. Bone Joint Surg. 74B:760, 1992. 32. Tibone, J. E., and Stoltz, M.: Fractures of the radial head and neck in children. J. Bone Joint Surg. 63A:100, 1981. 33. Vahvanen, V., and Gripenberg, L.: Fracture of the radial neck in children. A long-term follow-up study of 43 cases. Acta Orthop. Scand. 49:32, 1978. 34. van Rhijn, L. W., Schuppers, H. A., and van der Eijken, J. W.: Reposition of a radial neck fracture by a percutaneous Kirschner wire. A case report. Acta Orthop. Scand. 66:177, 1995. 35. Vocke, A. K., and Von Laer, L.: Displaced fractures of the radial neck in children: Long-term results and prognosis

36.

37. 38.

39.

of conservative treatment. J. Pediatr. Orthop. Part B. 7:217, 1998. Ward, W. T., and Williams, J. J.: Radial neck fracture complicating closed reduction of a posterior elbow dislocation in a child: case report. J. Trauma 31:1686, 1991. Waters, P. M., and Stewart, S. L.: Radial neck fracture nonunion in children. J. Pediatr. Orthop. 21:570, 2001. Weber, B. G., Brunner, C. H., and Freuler, F.: Treatment of fractures in children and adolescents. Berlin, SpringerVerlag, 1980, p. 172. Wedge, J. H., and Robertson, D. E.: Displaced fractures of the neck of the radius in children. J. Bone Joint Surg. 64B:256, 1982.

Chapter 18 Proximal Ulnar Fractures in Children

CHAPTER

18

Proximal Ulnar Fractures in Children Anthony A. Stans and Bernard F. Morrey

283

review of the literature of the less rare olecranon or proximal ulnar fracture resulted in the identification of 192 cases but no mention of a fracture of the apophysis.17 The fracture may or may not include the coronoid as the fracture line passes between the growth center and the proximal ulna (see Fig. 18-2). This is because the coronoid does not develop from a separate growth center; thus, the fracture line in this rarest of fractures may be rather variable (Fig. 18-3).

TREATMENT

INTRODUCTION Proximal ulnar fractures in children and adolescents are uncommon, accounting for between 4% and 7% of pediatric and adolescent elbow fractures.1,2,6,8 As a result, (1) they are often completely missed, (2) the variation in growth centers makes the radiographic interpretation confusing, (3) the precise fracture line is often not appreciated, and (4) the potential for a poor outcome occurs if the displacement is not appreciated. In this chapter, we review fractures of the physis, metaphysis, and coronoid (Table 18-1).

The extreme rarity of this fracture makes it difficult to make definitive recommendations for treatment. If the fracture is displaced, basic principles apply; that is, reduce the fracture anatomically. Smooth K-wires, possibly supplemented with a figure-of-eight wire as recommended by the Arbeitsgemeinschaft für osteosynthese fragen (AO) technique for olecranon fractures, appears to be adequate, based on the limited reports from the literature. The major challenge, of course, is to diagnose the displacement. Today, computed tomography (CT) scanning, magnetic resonance imaging (MRI), and ultrasonography are useful for this purpose.

GROWTH AND DEVELOPMENT

METAPHYSEAL FRACTURE

As noted in Chapter 1, at birth none of the articular elements of the ulna, including the coronoid and olecranon, are ossified. At age 9, the secondary center of ossification appears at the olecranon (Fig. 18-1). The ossification center may be bipartite and eccentric, and as the proximal ulna grows, the growth plate orientation alters from transverse to oblique. Closure of the physis begins at the articular surface and progresses toward the extensor surface of the bone. Just before fusion of the growth plate, the metaphyseal bone develops a sclerotic margin and may be widely separated from the apophysis, resembling a fracture. These vagaries can make it difficult to recognize a fracture of the olecranon in a child, and comparative views of the opposite side are often valuable.2 Although a secondary center may appear in the olecranon tip, there is no secondary ossification center of the coronoid. This helps explain the fracture pattern observed in the proximal ulna of the various age groups (Fig. 18-2).

Metaphyseal fractures, although more common than fracture of the apophysis, still account for only approximately 5% of elbow injuries.3,11,15 Wilkins17 identified only 230 cases among 4,684 proximal ulnar fractures reported in the child before 1991. It appears that there is a biphasic frequency by age, with the greatest early frequency occurring between 5 and 6 years12 and a second incidence observed in the adolescent. The first peak probably relates to the growth and development of the bone. The second peak relates to the growth and development of the individual participating in activity with increasing propensity for injury. The mechanism of injury is similar to that described for many injuries about the elbow, including supracondylar, condylar fractures, and dislocations. Although proximal ulna fractures may be caused by direct impact, a more common mechanism is a fall onto an outstretched hand with transmission of the force proximally to the elbow. Differences in injury pattern probably relate to the precise degree of elbow flexion, possibly the rotation of the forearm, and the manner in which the muscles contracted at the time of impact. With fracture of the metaphysis, a varus or valgus force often occurs, causing additional fractures about the elbow. In four large series of proximal ulnar fractures, 20% had a documented associated fracture.17 In some reports, as

APOPHYSEAL FRACTURE Apophyseal fractures are extremely rare. Reviewing his experience and that of the literature up to 1991, Wilkins17 identified only 16 such cases. As a matter of fact, a

Part IV Conditions Affecting the Child’s Elbow

284

Types of Proximal Ulnar Fracture in the Pediatric Age Group

TABLE 18-1 Type

Incidence

Apophyseal (physeal, epiphyseal)

Very rare

Metaphyseal

5% of elbow fractures

Coronoid

Less than 1% of elbow fractures

A

associated injury (±4 mm being the limit). Wilkins17 considered these by the mechanism of the fracture: (A) flexion; (B) extension; (1) valgus; (2) varus; and (C) shear injury. More recently, Graves and Canale7 classified the fracture according to (1) displacement greater or less than 5 mm and (2) presence of compounding. This classification was subsequently modified by Gaddy and coworkers,3 with a type I fracture being less than 3 mm and a type II greater than 3 mm. Evans and Graham2 have proposed a classification system based on anatomic site, fracture configuration, intra-articular displacement, and associated injuries, with approximately 18 subtypes. Thus, this fracture has the interesting characteristic of having almost as many classifications as episodes of occurrence. Although metaphyseal fractures are extremely uncommon, as noted, they are more frequent than the physeal injury is, and they account for approximately 5% of all elbow injuries. Of these, only 10% to 20% require surgical management. Rarely, proximal ulna fractures may be associated with ipsilateral fractures in the distal humerus,9 ulnar shaft,13 or radial head.4

DIAGNOSIS

B FIGURE 18-1

Schematic of ossification of the proximal ulna observed at birth (A) and at adolescence (B). This explains the fracture patterns seen in the young and the adolescent age groups.

Because the fracture involves ossified tissue, the metaphyseal fracture is relatively easily identified on the radiograph. Abrasion of the skin or open wound gives some idea of the mechanism; that is, direct or indirect trauma, respectively. A further means of determining the extent of displacement and hence the need for open reduction and internal fixation is to observe whether the fracture separates with flexion and extension under fluoroscopy. If an excessive amount of motion is observed at the fracture site (3 to 4 mm), then open reduction and internal fixation are carried out.

TREATMENT

FIGURE 18-2

Fracture of the apophysis may (open arrow) or may not (closed arrow) include the coronoid process.

many as 50% to 70% had an additional injury, most commonly involving the radial head with a valgus stress at the time of impact (Fig. 18-4).2,14,16

CLASSIFICATION In 1981, Matthews10 offered a classification based on radiographic appearance, degree of displacement, and

As implied from the above-mentioned classification, the approach to treatment is based primarily on fracture displacement. Fortunately, approximately 80% of these fractures are minimally displaced, requiring open reduction and internal fixation in only 15% to 20% of individuals.2 Reduction may be accomplished in most instances by reversing the mechanism, which provides some justification for Wilkins’ mechanistic classification noted earlier. For those fractures that are minimally displaced, simple immobilization for approximately 3 weeks appears to be adequate and is the universal recommendation. For displacement of greater than 3 mm, depending on the classification, surgical treatment is indicated. It is uncommon to have greater than 4 mm displace-

Chapter 18 Proximal Ulnar Fractures in Children

285

A

C

FIGURE 18-3

B

ment in patients under the age of 10 years; thus, open reduction and internal fixation are generally observed in the older age group. Several authors have noted that displacement found intraoperatively is often significantly greater than displacement appreciated on plain radiographs.3,7 Typically, the AO technique with smooth Kwire with circumferential tension band wire is adequate (Fig. 18-5). Recently, there have been several reports successfully using heavy absorbable suture in tension band technique instead of wire.2,5 Absorbable suture was prominent, less likely than wire to become symptomatic and did not need to be removed. Metal internal fixation is typically removed 6 to 12 months postoperatively to ensure that premature closure of the proximal ulnar physis does not occur, and to relieve symptoms of proximal hardware. There have been no reported cases

A 13-year-old boy slipped and fell onto his left arm and presents with point tenderness over his olecranon. (A) Lateral radiograph suggests an olecranon apophysis fracture, which is confirmed by comparison with the contralateral uninjured elbow (B). At the time of his olecranon fracture, the patient was using crutches because he had sustained a left femur fracture 1 month earlier in a motor vehicle accident. The decision was made to perform open reduction with tension band internal fixation (C).

of premature proximal ulnar physeal closure using this internal fixation technique.

RESULTS Graves and Canale7 reported the results of 39 fractures treated over 30 years at the Campbell Clinic. Twentyeight of 30 patients treated nonoperatively were classified as satisfactory after closed treatment. Of the nine treated by open reduction and internal fixation, seven (78%) developed a satisfactory result. Gaddy and colleagues3 reported 35 fractures occurring in patients ranging from 2 months to 15 years. Of these, all 23 treated nonoperatively were considered satisfactory. The criterion for nonoperative treatment was displacement of less than 3 mm. Furthermore, 10 of 10 patients with

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Part IV Conditions Affecting the Child’s Elbow

greater than 3 mm of displacement underwent open reduction and internal fixation, and all developed a satisfactory outcome. Evans and Graham2 reported the results of 40 proximal ulna fractures treated surgically. In the text of their article a detailed treatment algorithm is provided, outlining their indications for surgical treatment. In summary, fractures greater than 4 mm were always treated surgically, fractures with less than 2 mm of displacement were never treated surgically, and treatment of fractures with displacement between 2 and 4 mm was determined by anatomic site, fracture configuration, and associated injuries. Thirty-six of 40 fractures were managed by tension band technique; 28 using wire and eight using absorbable suture. In the end, following a simple classification based on the degree of displacement appears to be a reliable guide to surgical intervention and good outcome.

COMPLICATIONS

FIGURE 18-4

The metaphyseal fracture involves the ossified proximal ulna. Varus or valgus angulation patterns assist in documenting the mechanism of injury.

As implied by the above-mentioned comments, the complications are uncommon; thus, approximately a 95% satisfactory outcome is observed whether the fracture is managed operatively or nonoperatively. The most common sequela of the fracture is slight limitation of

B

A

FIGURE 18-5

C

A 10-year-old girl fell 3 feet from a desk directly onto her left elbow, sustaining a proximal ulnar fracture (A) and transcondylar humerus fracture associated with an intra-articular loose bone fragment. Four weeks after open reduction and internal fixation of the proximal ulna and distal humerus, anatomic alignment and periosteal healing are demonstrated (B). Two years following her fracture and 18 months following removal of the tension band wire, the fractures have completely healed, elbow motion is full and without limit, and the patient is entirely asymptomatic (C).

Chapter 18 Proximal Ulnar Fractures in Children

287

References

FIGURE 18-6 Plain film and three-dimensional reconstruction of stress fracture of the coronoid (arrow) observed in a 17-year-old gymnast. The symptoms resolved with rest. (Courtesy of A. Rettig, Indianapolis, IN.)

extension. Ectopic bone does not appear to be a problem.

FRACTURE OF THE CORONOID Because there is no secondary center of ossification, fracture of the coronoid as an isolated fracture is rare. As in the adult, injury to this structure is seen primarily with severe trauma or elbow dislocation. When a coronoid fracture is observed, a high level of suspicion should be aroused that a concurrent elbow dislocation has occurred.15 We have also seen in consultation a stress fracture of the coronoid in a 17-year-old gymnast (Fig. 18-6). Treatment is predicated on the integrity of the ulnohumeral joint; thus, the elbow is reduced and stability is ensured (see Chapters 27 and 29). The coronoid fracture in the child is then treated as a secondary consideration and frequently nothing need be done if the elbow is stable. We have not seen nor reported a large coronoid fracture as an isolated injury requiring open reduction and internal fixation in the child.

1. Dormans, J., and Rang, M.: Fractures of the olecranon and radial neck in children. Orthop. Clin. North Am. 21:257, 1990. 2. Evans, M. C., and Graham, K.: Olecranon fractures in children, part I: a clinical review. Part II: a new classification and management algorithm. J. Pediatr. Orthop. 19:559, 1999. 3. Gaddy, B. C., Strecker, W. B., and Schoenecker, P. L.: Surgical treatment of displaced olecranon fractures in children. J. Pediatr. Orthop. 17:321, 1997. 4. Gicquel, P. H., De Billy, B., Carger, C. S., and Clavert, J. M.: Olecranon fractures in 26 children with mean follow-up of 59 months. J. Pediatr. Orthop. 21:141, 2001. 5. Gortzak, Y., Mercado, E., Atar, D., and Weisel, Y.: Pediatric olecranon fractures: open reduction and internal fixation with removable Kirschner wires and absorbable sutures. J. Pediatr. Orthop. 26:39, 2006. 6. Grantham, S. A., and Kiernan, H. A.: Displaced olecranon fracture in children. J. Trauma 15:197, 1975. 7. Graves, S., and Canale, T.: Fractures of the olecranon in children. Long-term follow-up. J. Pediatr. Orthop. 13:239, 1993. 8. Henrikson, B.: Supracondylar fracture of the humerus in children. Acta Chir. Scand. 369:1, 1966. 9. James, P., and Heinrich, S. D.: Ipsilateral proximal metaphyseal and flexion supracondylar humerus fractures with an associated olecranon avulsion fracture. Orthopedics 14:713, 1991. 10. Matthews, J. G.: Fractures of the olecranon in children. Injury 12:207, 1981. 11. Maylahn, D. J., and Fahey, J. J.: Fractures of the elbow in children. J. A. M. A. 166:220, 1958. 12. Newell, R. L. M.: Olecranon fractures in children. Injury 7:33, 1975. 13. Olney, B. W., and Menelaus, M. B.: Monteggia and equivalent lesions in childhood. J. Pediatr. Orthop. 9:219, 1989. 14. Papavasilou, V. A., Beslikas, T. A., and Nenopoulos, S.: Isolated fractures of the olecranon in children. Injury 18:100, 1987. 15. Regan, W., and Morrey, B. F.: Fractures of the coronoid process of the ulna. J. Bone Joint Surg. 71A:1348, 1989. 16. Theodorou, S. D.: Dislocation of the head of the radius associated with fracture of the upper end of the ulna in children. J. Bone Joint Surg. 51B:700, 1969. 17.Wilkins, K. E.: Fractures involving the proximal apophysis of the olecranon. In Rockwood, C. A., Wilkins, K. E., and King, R. E. (eds.): Fractures in Children. Philadelphia, J. B. Lippincott, 1991, p. 751.

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CHAPTER

19

Osteochondritis Dissecans William J. Shaughnessy

by motion or use, particularly by throwing or other violent motions. It usually occurs in boys and always during the period of active ossification of the capitellar epiphysis (ages 7 to 12, peak at 9 years). Panner’s disease is not seen before age 5 years. In addition to pain, loss of 5 to 20 degrees of elbow extension is common. Local swelling and tenderness over the lateral side of the elbow is not unusual.23 Symptoms resolve over time with few sequelae.

RADIOGRAPHIC CHARACTERISTICS

INTRODUCTION Osteochondral lesions may be the source of chronic elbow pain, swelling, and loss of motion in children or adolescents. The typical presentation is an adolescent gymnast or baseball pitcher.13,34 The dominant arm is usually involved, but may be bilateral in approximately 5% to 20%.34,41 It is important to distinguish between osteochondrosis of the capitellum, or Panner’s disease, and osteochondritis dissecans. The distinction, based on patient age and degree of involvement of the capitellar secondary ossification center, has received only sporadic attention in the literature. It is possible, however, that the two conditions represent different stages of a single process that affects the formation and maturation of the capitellar epiphysis.

OSTEOCHONDROSIS OF THE CAPITELLUM (PANNER’S DISEASE)

Osteochondrosis of the capitellum is a focal or localized avascular lesion of subchondral bone and its overlying articular cartilage.11 Radiographically, there is fragmentation of the capitellar epiphysis. The fragmentation is due to irregular patches of relative sclerosis alternating with areas of rarefaction (Fig. 19-1A and B). The outline of the epiphysis may be slightly irregular and smaller than that of the opposite normal capitellar epiphysis. Despite the radiographic fragmentation, osteochondral loose bodies do not form. As growth progresses, the capitellar epiphysis eventually assumes a normal appearance in size, contour, and internal architecture as clinical symptoms resolve. Residual deformity of the capitellum is rare. Magnetic resonance imaging (MRI) findings include decreased signal intensity of the ossified epiphysis on T1-weighted images. Both plain films and MRI images of osteochondrosis of the capitellum are similar to findings in Legg-Calvé-Perthes disease of the hip.25 Deformity and collapse of the articular surface is less common in osteochondrosis of the capitellum than in Perthes’ disease of the hip.

INTRODUCTION

TREATMENT

Osteochondrosis is defined as a disease of the growth or ossification centers in children that begins as a degeneration or necrosis, followed by regeneration or recalcification. Familiar sites of osteochondrosis in children include the proximal femur (Perthes’ disease) and the tarsal navicular (Kohler’s disease). Osteochondrosis of the capitellum is also called Panner’s disease, or osteochondrosis deformans capitelli humeri. Osteochondrosis of the capitellum and osteochondritis dissecans may represent two manifestations of the same condition in different aged children. The different outcomes and treatments of the two groups makes it more useful to consider them separately.

Because osteochondrosis of the capitellum is a benign, self-limited condition, no active treatment is necessary. Activity modifications and rest for symptomatic relief are usually sufficient. The prognosis is good.

CLINICAL CHARACTERISTICS Osteochondrosis of the capitellum is characterized by dull, aching pain in the elbow that usually is aggravated

OSTEOCHONDRITIS DISSECANS INTRODUCTION Osteochondritis is defined as an inflammation of both bone and cartilage. Osteochondritis dissecans is described as osteochondritis resulting in the splitting of pieces of cartilage into the joint (in Dorland’s Medical Dictionary). The term osteochondritis dissecans was given to this condition by Franz Konig in 1889, who described a knee condition that appeared to suggest a subchondral inflammatory process that dissected a fragment of cartilage from the

Chapter 19 Osteochondritis Dissecans

289

FIGURE 19-1

A, Anteroposterior view of the right elbow of a 9-year-old boy shows involvement of the entire capitellum in alternating irregular areas of sclerosis and patchy rarefaction. B, The lateral view shows osteochondrosis.

femoral condyle, leading to formation of a loose body.20 Although no inflammatory process has ever been shown to produce such lesions, the name has remained. Osteochondritis dissecans of the capitellum is similar to osteochondritis dissecans in other joints, such as the knee. It involves localized avascular necrosis of subchondral bone and subsequent loss of structural support for the adjacent articular cartilage. Compared with the knee, however, osteochondritis of the capitellum is much less common. Only 6% of patients with osteochondritis dissecans have elbow involvement.41 Because osteochondritis dissecans occurs after the capitellum has almost completely ossified (early adolescence), it should not be confused with osteochondrosis of the capitellum, nor is it due to an “inflammation,” in spite of the definition of osteochondritis cited earlier.41 Osteochondrosis dissecans and osteonecrosis of the capitellum have been suggested as more appropriate terms, but are rarely used today. From a practical standpoint, the localized area of osteochondritis, consisting of articular cartilage and underlying bone, either remains in situ and eventually heals or separates from the capitellum and becomes a loose body in the joint. Osteochondritis dissecans is one of several conditions that can cause “Little League elbow” in immature baseball players.38

CLINICAL CHARACTERISTICS Elbow pain, the most common complaint, is usually dull, poorly localized, and aggravated by use, particularly by athletic endeavors that involve throwing or weight bearing on the upper extremity. Use aggravates the condition and rest relieves it. Lateral elbow pain occurs in approximately 79% to 90% of patients.18,41 A second complaint, limitation of elbow motion, particularly extension, affects about 90% of patients. It is often associated with an effusion, and results in 5 to 20 degrees loss of elbow extension.18,41 Limitation of elbow flexion, pronation, and supination of the forearm also occur, but these problems are less common. Local tenderness over the lateral aspect of the elbow and crepitus with motion are other frequent complaints, but they are not as common as the dull pain and limited extension that occur with use. Later in the course of the disease, catching and locking of the elbow joint may be a prominent complaint; this usually represents separation of osseous or cartilage fragments.

RADIOGRAPHIC CHARACTERISTICS Anteroposterior and lateral radiographs of the elbow are useful and should be obtained in every case. Early in the disease, radiographic changes are most often con-

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fined to the capitellum.29 Rarefaction, irregular ossification, and a bony defect adjacent to the articular surface are frequent findings (Fig. 19-2). The crater of rarefaction in the capitellum usually has a sclerotic rim of subchondral bone adjacent to the articular surface. If the central fragment separates, one or more ossific loose bodies may be seen in the joint, and the articular surface of the capitellum may appear to be irregular or flattened, particularly on the lateral view. Only 30% of loose bodies can be seen on plain films.18 Computed tomography (CT) may be necessary to better define the bony anatomy (Fig. 19-3). MRI is the preferred imaging technique for assessing the extent of osteochondritis. MRI is also the best study to assess the integrity of the articular surface and the displacement of osteochondral fragments. Unstable lesions reveal fluid surrounding the osteochondral fragment on T2-weighted images (Fig. 19-4).8 Several other late radiographic changes are worth noting. As degenerative changes occur, the radial head enlarges. Klekamp described seven patients who had developmental dislocations of the radial head as a result of osteochondritis dissecans of the capitellum (Fig. 19-5).15 The cause-and-effect relationship is obscure. In a few instances, premature distal humeral physeal arrest is evident. Late in the course of disease, degenerative changes characterized by irregularity and incongruity of both the capitellar and radial head articular surfaces are evident; these changes are the most important late sequelae of this condition. If sequestration does not occur, the central sclerotic fragment gradually becomes less distinctive, the surrounding area of rarefaction slowly ossifies, and the lesion heals without significant sequelae. This radiographic evidence of healing may take several years to occur and sometimes is not complete until adult life, long after pain, swelling, and limitation of motion have disappeared (Fig. 19-6A and B).

ETIOLOGY Most of the speculation about the cause of osteochondritis dissecans has been directed toward the condition as it occurs in the knee, not in the elbow. There are three possible causes of osteochondritis dissecans: ischemia, trauma, and “genetic predisposition.”

Ischemia Because the initial histologic appearance of the involved segment of subchondral bone is that of avascular necrosis, one of the most popular theories holds that some type of ischemic insult affects a localized area of subchondral bone.23 The ischemic theory is based primarily on the histopathologic characteristics of the lesion and the vascular anatomy of the distal humerus.

FIGURE 19-2

Tomograms of the right elbow of a 16year-old boy with osteochondritis dissecans. Note the rarefied crater adjacent to the capitellar articular surface (type I lesion).

Haraldsson11 has shown that the vascular supply to the distal humerus is limited in persons aged 5 to 19 years. One or two isolated vessels enter the epiphysis posteriorly, traverse the nonossified cartilaginous epiphysis, and supply the capitellum. No vessels from the metaphysis cross the physis. Because these end arteries supplying the capitellum pass through compressible epiphyseal cartilage, repetitive valgus loading of the elbow may injure the vessels and lead to avascular areas within the epiphysis.34 This theory forms the basis for pitching limitations for young baseball pitchers. The microscopic changes in the involved area of subchondral bone are typical of those seen in bone infarction due to interruption of the subchondral terminal arterial vessels. Initially, the articular cartilage is intact, and the cartilage cells of the most superficial layers continue to receive their nutrition from synovial fluid. Early in the course of disease, hyperemia and edema of the synovium and metaphysis contribute to the eventual overgrowth of the capitellum and the proximal radius. Reparative changes characterized by absorption of necrotic bone by vascular granulation tissue occur at the interface between the necrotic subarticular segment and the normal surrounding bone. At this stage, a typical zone of rarefaction can be seen on radiographs, around the periphery of the lesion. If the articular cartilage remains intact and the necrotic segment remains in situ, the avascular segment is eventually absorbed; it is replaced by viable osseous tissue, and the normal architecture of the articular surface is

Chapter 19 Osteochondritis Dissecans

A

291

B

FIGURE 19-3 A, Coronal CT of the left elbow with osteochondritis dissecans. Note the radiolucent defect in the capitellum. Sequestrum within the capitellar defect. B, Lateral CT shows the irregular capitellum, the sclerotic defect and the bony fragment (sequestrum) within the defect. C, Lateral CT shows intraarticular loose body in the olecranon fossa.

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preserved. This healing process may take several years. If, however, the articular cartilage is fractured during the initial stage of the disease, the necrotic segment may become detached and an intra-articular loose body can form.

Trauma

FIGURE 19-4

Lateral magnetic resonance imaging scan of the elbow with osteochondritis dissecans. There is a defect in the capitellum, sequestrum surrounded by joint fluid, posterior loose body, and an elbow effusion.

For nearly 100 years, trauma has been suggested as a cause of osteochondritis dissecans. Unfortunately, no experimental data support this or any other theory.17,27 A history of frequent repetitive overuse of the elbow is common in persons who have osteochondritis dissecans. Several authors have noted a relationship between osteochondritis dissecans and baseball pitching.1,4,37,40 The valgus compressive forces generated across the radiocapitellar joint during throwing are believed to induce changes in the distal humerus that lead to osteochondritis dissecans.14 Repetitive trauma also is thought to play a role in the development of the condition in adolescent gymnasts,13,34 who bear their entire body weight on their arms and thus expose their elbows to repetitive compressive forces. Repetitive trauma, particularly forceful extension and pronation of the elbow, creates compression and shearing forces that are transmitted by the radius to the adjacent articular surface of the capitellum. This trauma results in separation and infarction of an area of subchondral bone and the overlying articular cartilage. From a study of cadaver elbows, Schenck suggested that the mechanical disparity between a stiff radial head articulating with a less stiff capitellum produces strain during compressive stresses that can lead to osteochondritis dissecans.33

Genetic Factors Numerous but sporadic reports describe osteochondritis of the capitellum in one or in several generations of the same family.9,19,25,41 Osteochondritis dissecans has also been reported to occur in more than one joint in a given patient or in more than one family member. Neilson21 reported the incidence of osteochondritis dissecans to be 4.1 per 1000 men. Among male relatives of affected men, he found an incidence of 14.6%. In spite of these reports, there is no convincing evidence that osteochondritis dissecans of the capitellum is a heritable disease. Multiple epiphyseal dysplasia, which is a rare heritable condition, superficially has many features that are similar to those of this condition.7 Multiple epiphyses are involved. The clinical course and prognosis, however, are in no way similar.

TREATMENT FIGURE 19-5

Lateral view of the elbow in a 16-year-old boy with osteochondritis dissecans. Note the posterolateral subluxation of the radial head.

Treatment of osteochondritis dissecans is dictated by the clinical findings and the radiographic appearance of the lesion. Initial treatment is usually nonoperative:

Chapter 19 Osteochondritis Dissecans

293

FIGURE 19-6

A, Anteroposterior view of a type I lesion in a 14year-old boy with osteochondritis dissecans. B, Anteroposterior view made 1 1/2 years later. The zone of rarefaction surrounding the lesion is becoming less distinct, and the patient is asymptomatic.

limitation of activities and nonsteroidal anti-inflammatory medications. Rest and protection is continued for several weeks. If these methods fail, good results have been obtained with surgical management. Functional limitations are common. Routine radiographs, CT, and MRI may be necessary to determine whether the involved segment has been separated from the capitellum. If an osteochondral fragment is loose within the joint, the diagnosis can usually be made by clinical examination and routine radiographs. Arthroscopy is useful for removing loose bodies from the elbow joint and for treating the capitellar defect with curettage or drilling or microfracture. The condition of the articular surfaces can be visualized by arthroscopy as well.

Intact Lesions If the lesion is intact with no evidence of displacement from its normal site or of fracture of the articular cartilage, nonoperative treatment is indicated.27 The elbow should be rested and any vigorous use avoided. Application of ice and the use of a nonsteroidal antiinflammatory medication may relieve symptoms. A hinged elbow brace may be useful to limit activities.28 If pain is a significant complaint, the elbow should be splinted or placed in a cast for 3 to 4 weeks, after which active range-of-motion exercises are prescribed to preserve motion. Activity should be restricted for 6 to 8

weeks after symptoms have resolved. Radiographic changes should be stable or improving before the patient resumes activities. It is unreasonable to restrict all activities until radiographs are normal, because abnormalities can persist for years. When activities are allowed, they should be gradually “advanced” and modified if any symptoms recur. A history of locking or catching should prompt a search for loose or partially attached fragments.34 If symptoms persist but the articular cartilage remains intact, arthroscopic or open antegrade or retrograde subchondral drilling is considered. Patients with intact lesions treated nonoperatively generally do well.34,41 Most athletes can return to sports, with the exception of baseball pitchers and gymnasts, whose prognosis is more guarded.36,37 With longer follow-up, results are not as good. Takahara, with follow-up of 12 years, found that 50% had clinical and radiographic evidence of osteoarthritis.36

Partially Attached Fragments If radiographic evaluation or arthroscopic examination finds evidence of fracture or fissure of the articular cartilage or of partial detachment of the fragment, the surgeon has two choices: (1) to reattach the area of avascular bone surgically or (2) to excise the loose fragment.27 In this situation, as in the knee, a partially detached fragment can be pinned in situ with Kirschner wires,

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Herbert screws, or bioabsorbable implants13,16 under direct vision or arthroscopic control. In situ fixation of large, partially attached or hinged lesions may be useful in preventing complete detachment, loose body formation, and ultimate osteoarthritis.36 The additional value of repeated drilling of the fragment and its bony bed to stimulate revascularization and healing has never been conclusively established. In general, only limited success has been reported from attempts to pin partially attached articular fragments once the underlying bone is exposed.10

Completely Detached Fragments When the area involved with osteochondritis dissecans has completely detached from the capitellum and is lying free in the joint, the most effective treatment is to remove the fragment surgically, by arthroscopy or arthrotomy.2,13,16,27,34,41 Surgical indications include locking, symptomatic loose bodies, and failure of prolonged nonoperative treatment to relieve symptoms.18,37,41 Arthroscopic techniques using standard 4-mm instruments have been shown to be effective in evaluating and treating elbow disorders such as osteochondritis dissecans.2,10,13 Care must be taken to avoid complications such as nerve palsies.2,26 Most authors agree that the best short-term results are obtained with simple excision of the loose body. Removing the loose body is usually effective in relieving the patient’s pain and mechanical symptoms, although the range of motion may not increase. Late degenerative arthritis may still be the ultimate outcome in as many as 50%.36 Because of evidence that large defects can facilitate degenerative changes, many authors have advocated more complex procedures for such defects. These procedures include drilling, microfracture, fixation, autograft replacement, and autologous cell implantation. Unfortunately, there is little evidence and no long-term follow-up to show that these techniques can prevent the development of osteoarthritis. Procedures other than simple excision are commonly reported but not strongly supported by long follow-up in the literature.2,18,26,34,41 Ruch30 treated 12 elbows with arthroscopic débridement and reported 13 degrees more extension and improved symptoms in 11 elbows (92%) at 3-year follow-up. Curettage and drilling of the defect in the capitellar articular surface is advocated by many.5,12,13,18,31,35,37 The benefit of this approach is difficult to document. In at least two series, the results were no better after drilling, curettage, or trimming of the crater than after removal of the loose body and débridement alone.30,4` Results are worst with complex procedures involving open excision of the capitellum, bone grafting, and internal fixation of the loose fragment.37,41 Chondral resurfacing and osteochondral grafting procedures have been reported for osteochondritis dissecans of the elbow,

but numbers are too small and follow-up is too short to draw conclusions.22,32,39 Short-term postoperative results of arthroscopic loose body removal and débridement vary from series to series. The prognosis for returning to sports varies widely by report but is guarded, especially in throwing sports and gymnastics. McManama and colleagues found that 12 of 14 (86%) patients returned to competitive athletics without restrictions and that elbow range of motion increased 18 degrees after surgeons removed loose bodies, shaved chondral defects, and drilled multiple holes to promote revascularization.18 Tivnon and coworkers37 found a similar 21-degree improvement in range of motion after removal of loose bodies and curettage of the capitellum and improved function in 10 of 12 elbows. After removal of loose bodies, shaving, subchondral drilling, or a combination of these, Janarv and colleagues12 reported that all patients had fewer symptoms or no symptoms and improved elbow motion. Rupp and Tempelhof31 reported mixed results in six patients treated with loose body removal, drilling of the lesion, or débridement of the defect. Results were related to the degree of articular cartilage damage. Singer and Roy34 reported on five female gymnasts with osteochondritis dissecans of the capitellum; two required surgery to excise loose fragments. At 3-year follow-up, all but one had been able to return to competition. In a similar study of gymnasts, Jackson and colleagues found that only one of seven patients was able to continue competitive gymnastics.13 Byrd and Jones treated 10 elbows in adolescent baseball pitchers. All had improved pain but only 4 of 10 (40%) returned to their prior level of activity.6 Tivnon and coworkers37 reported similar (guarded) results among 12 baseball pitchers, only one of whom was able to throw at his prior level. The long-term prognosis for patients with osteochondritis dissecans of the capitellum depends on the patient’s age and on the size and extent of the lesion. Young patients have more favorable outcomes. Large defects that require surgery in older adolescents often progress to degenerative arthritis. Woodward and Bianco41 (with an average 12-year follow-up, range 2 to 34 years) suggest that most patients believed that they had normal use of their elbow. Bauer and colleagues3 suggest that osteochondritis dissecans of the capitellum leads to osteoarthritis in the majority of patients at longterm follow-up.

SUMMARY Osteochondritis dissecans of the capitellum is an uncommon problem that affects adolescents, especially those engaged in repetitive throwing and gymnastics.

Chapter 19 Osteochondritis Dissecans

Compressive forces at the radiocapitellar joint, along with a tenuous blood supply to the region, may contribute to the development of this condition. Most affected persons are adolescents, who initially note lateral elbow pain, loss of extension, and swelling. These symptoms are aggravated by activity and improve with 6 to 8 weeks of rest. Plain radiographs are usually sufficient to make the diagnosis, although CT, MRI, and arthroscopy may be necessary. It is important to distinguish osteochondritis dissecans from Panner’s disease, a benign, self-limited condition that affects the capitellum in younger children. Intact osteochondral lesions usually respond well to activity limitations. Many of these lesions heal, and the patients are able to return to activities. Failed nonoperative treatment or a symptomatic loose body is an indication for surgery, which should aim to remove loose fragments. Curettage of the defect or drilling of the subchondral bone may be useful, but this remains to be proved with long-term follow-up. The place for more complex surgical procedures such as internal fixation, osteochondral grafting, and autologous chondrocyte transplantation, remains to be determined. The shortterm prognosis is good, but a return to high-level competitive athletics involving throwing or gymnastic moves is not possible in many cases.

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11. Haraldsson, S.: On osteochondrosis deformans juvenitis, capituli humeri including investigation of intraosseous vasculature in distal humerus. Acta Orthop. Scand. Suppl. 38:1, 1959. 12. Janarv, P. M., Hesser, U., and Hirsch, G.: Osteochondral lesions in the radiocapitellar joint in the skeletally immature: radiographic, MRI, and arthroscopic findings in 13 consecutive cases. J. Pediatr. Orthop. 17:311, 1997. 13. Jackson, D. W., Silvino, N., and Reiman, P.: Osteochondritis in the female gymnast’s elbow. Arthroscopy 5:129, 1989. 14. King, J. W., Brelsford, H. S., and Tullos, H. S.: Analysis of the pitching arm of the professional baseball pitcher. Clin. Orthop. 67:116, 1969. 15. Klekamp, J., Green, N. E., and Mencio, G. A.: Osteochondritis dissecans as a cause of developmental dislocation of the radial head. Clin. Orthop. 338:36, 1997. 16. Kuwahata, Y., and Inoue, G.: Osteochondritis dissecans of the elbow managed by Herbert screw fixation. Orthopedics 21:449, 1998. 17. Lindholm, T. S., Osterman, K., and Vankka, E.: Osteochondritis dissecans of elbow, ankle, and hip. Clin. Orthop. 148:245, 1980. 18. McManama, G. B., Michel, L. J., Berry, M. V., and Sohn, R. S.: The surgical treatment of osteochondritis of the capitellum. Am. J. Sports Med. 13:11, 1985. 19. Mitsunaga, M. M., Adishian, D. O., and Bianco, A. J. Jr.: Osteochondritis dissecans of the capitellum. J. Trauma 22:53, 1982. 20. Naguro, S.: The so-called osteochondritis dissecans of Konig. Clin. Orthop. 18:100, 1960. 21. Neilson, N. A.: Osteochondritis dissecans capituli humeri. Acta Orthop. Scand. 4:307, 1933. 22. Oka, Y., and Ikeda, M.: Treatment of severe osteochondritis dissecans of the elbow using osteochondral grafts from a rib. J. Bone Joint Surg. 83B(5):738, 2001. 23. Omer, G. E. J.: Primary articular osteochondroses. Clin. Orthop. 158:33, 1981. 24. Paes, R. A.: Familial osteochondritis dissecans. Clin. Radiol. 40:501, 1989. 25. Panner, H. J.: A peculiar affection of the capitellum humeri, resembling Calve-Perthes disease of the hip. Acta Radiol. 8:617, 1927. 26. Papilion, J. D., Neff, R. S., and Shall, L. M.: Compression neuropathy of the radial nerve as a complication of elbow arthroscopy: a case report and review of the literature. Arthroscopy 4:284, 1988. 27. Pappas, A. M.: Osteochondritis dissecans. Clin. Orthop. 158:59, 1981. 28. Peterson, R. K., Savoiem, F. H. 3rd, and Field, L. D.: Osteochondritis dissecans of the elbow. Instr. Course Lect. 48:393, 1999. 29. Roberts, N., and Hughes, R.: Osteochondritis dissecans of the elbow joint: a clinical study. J. Bone Joint Surg. 32B:348, 1950. 30. Ruch, D. S., Cory, J. W., and Poehling, G. G.: The arthroscopic management of osteochondritis dissecans of the adolescent elbow. Arthroscopy 14:797, 1998. 31. Rupp, S., and Tempelhof, S.: Arthroscopic surgery of the elbow. Therapeutic benefits and hazards. Clin. Orthop. 313:140, 1995.

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32. Sato, M., Ochi, O., Uchio, Y., Agung, M., and Baba, H.: Transplantation of tissue-engineered cartilage for excessive osteochondritis dissecans of the elbow. J. Shoulder Elbow Surg. 13:221, 2004. 33. Schenck, R. C., Athanasiou, K. A., Constantinides, G., and Gomez, E.: A biomechanical analysis of articular cartilage of the human elbow and a potential relationship to osteochondritis dissecans. Clin. Orthop. 299:305, 1994. 34. Singer, K. M., and Roy, S. P.: Osteochondrosis of the humeral capitellum. Am. J. Sports Med. 12:351, 1984. 35. Smillie, I. S.: Osteochondritis Dissecans: Loose Bodies in Joints; Etiology, Pathology, Treatment. Edinburgh, E. & S. Livingstone, 1960. 36. Takahara, M., Ogino, T., Sasaki, I., Kato, H., Minami, A., and Kaneda, K.: Long term outcome of osteochondritis

37.

38. 39.

40.

41.

dissecans of the humeral capitellum. Clin. Orthop. 363:108, 1999. Tivnon, M. C., Anzel, S. H., and Waugh, T. R.: Surgical management of osteochondritis dissecans of the capitellum. Am. J. Sports Med. 4:121, 1976. Torg, J. S.: Little League: the theft of a carefree youth. Physician Sports Med. 1:72, 1973. Tsuda, E., Ishibashi, Y., Sato, H., Yamamoto, Y., and Toh, S.: Osteochondral autograft transplantation for osteochondritis dissecans of the capitellum in non-throwing athletes. Arthroscopy 21:177.e1, 2005. Tullos, H. S., Erwin, W. D., Woods, G. W., Wukasch, D. C., Cooley, D. A., and King, J. W.: Unusual lesions of the pitching arm. Clin. Orthop. 88:169, 1972. Woodward, A. H., and Bianco, A. J. Jr.: Osteochondritis dissecans of the elbow. Clin. Orthop. 110:35, 1975.

Chapter 20 Dislocations of the Child’s Elbow

CHAPTER

20

Dislocations of the Child’s Elbow R. Merv Letts and Bernard F. Morrey

INTRODUCTION Dislocation of the elbow in children is the most common childhood dislocation, constituting about 6% to 8% of elbow injuries.72,118 In general, however, because the attachments of ligaments and muscles are stronger than the adjacent growth plate, forces exerted about most joints tend to result in epiphyseal injury rather than simple dislocation of the adjacent joint. The elbow is unique in children because type I and II fractures through the distal humeral epiphysis are uncommon; hence, the finding for dislocation. The purpose of this chapter is to discuss the practical aspects of the cause, recognition, and the management of dislocations about the elbow joint in children. Because the elbow is the most common joint injured in childhood, the chapter on imaging (see Chapter 12) and chapters dealing with images of other conditions (see Chapters 14 to 18 and 21) should be carefully studied.

ANATOMIC FACTORS PREDISPOSING TO ELBOW DISLOCATION IN CHILDREN Although the anatomy of the elbow joint was thoroughly discussed in Chapter 2, it is important to emphasize some of the anatomic differences that are unique to the pediatric elbow joint.

GROWTH PLATES, APOPHYSIS, AND SECONDARY CENTERS OF OSSIFICATION To a casual observer, the radiograph of a child’s elbow is an enigma—no two ever seem alike. The reason for this, of course, is that because the child is constantly growing, ossification centers are appearing and fusing, and cartilage is calcifying progressively until skeletal maturity is attained. It is important to emphasize that there is usually a normal contralateral control that can be radiographed and compared with the radiograph of the injured

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elbow. This is not recommended as a routine practice, but sometimes it is necessary and useful, especially for those who treat elbow injuries in children only occasionally. In general, the younger the child at the time of injury, the more difficult it is to assess the elbow, owing to the larger percentage of cartilage that is present about the elbow joint. Fortunately, new imaging modalities allow more accurate assessment.7,8 Yet, in the newborn or infant, it may be very difficult to diagnose an elbow injury or to determine whether it is a transcondylar fracture or a dislocation of the elbow (the former being much more common at this age). The ossific nuclei about the elbow joint are helpful in radiologic interpretation of elbow dislocation (see Chapter 12). The capitellum, whose center of ossification should be present by 6 months of age, facilitates the interpretation of radial head alignment, because a line drawn through the radial head should always intersect the capitellum no matter what view is taken (Fig. 20-1). This interpretation is improved even further with the appearance of the radial head secondary center of ossification, at around 5 years of age. The secondary center of ossification of the olecranon, which appears at about 9 years of age, allows a more accurate assessment of the position of the proximal ulna in relation to the distal humerus, an important consideration in the management of dislocations of the elbow in young children. Both the medial and the lateral apophyses of the distal humerus may be injured in dislocations of the elbow in a child. Although many mnemonics have been devised by residents trying to remember the timing of ossification of the various centers about the elbow, the most important center to remember from a practical standpoint is the medial epicondylar apophysis of the distal humerus. This center is usually present by the age of 5 to 6 years, and because it is frequently entrapped within the joint following a dislocation of the elbow, it should always be searched for and identified after this age. Hence, if the center cannot be identified, it should be assumed that it is within the joint itself. In children younger than the age of 5 years, the diagnosis of entrapment must be clinical or by arthrography, because the apophysis is entirely cartilaginous. The lateral epicondylar apophysis is injured less frequently. In posteromedial dislocations, it may suffer avulsion, owing to a severe varus strain on the elbow and may need to be repaired or fixed surgically.5

ELBOW FLEXIBILITY In children younger than 10 years of age, elbow stability is provided almost entirely by cartilage. Because of this, there is considerable flexibility in the elbow joint in children. It is not unusual for a child to be able to

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dromes,111,119 ligamentous laxity is enhanced and stability is accentuated.

OLECRANON The ulnohumeral joint provides the greatest articular stability in the elbow joint. In children, the coronoid process, which provides anterior stability resisting posterior dislocation of the ulna, is not well developed until about 12 years of age. Even at this age, the coronoid process is largely cartilaginous and, when stressed, is yielding and resilient. Similarly, the olecranon itself is a largely cartilaginous structure until the early teenage years. Neither the coronoid nor the olecranon fossa of the distal humerus is well developed until later in childhood, and they do not contribute as effectively to the “locking in” phenomenon in flexion and extension that occurs with well-ossified coronoid and olecranon processes.

RADIAL HEAD AND NECK

FIGURE 20-1

A, A line drawn through the middle of the neck and head of the radius must always pass through the capitellum in every view. B, If it does not, dislocation of the radial head is present.

hyperextend the elbow joint by 10 or 15 degrees and to have a much greater degree of laxity than is seen in an adult or even an adolescent. It is this combination of hyperflexibility and a lack of osseous stability in a joint subjected to considerable trauma that predisposes the elbow joint to dislocation. The major stabilizing ligaments on the medial and lateral sides are attached to the distal humerus through apophyses—structurally weak areas that are prone to avulsion with subsequent loss of joint integrity. In the many syndromes and conditions such as Ehlers-Danlos and cutis laxa syn-

The radial head and neck in children are cartilaginous but have the same relative diameters as the radial head and neck in adults. Dislocation of the radial head, either as an isolated event or in association with a Monteggia fracture, or with dislocation of the elbow joint itself, is facilitated by the resiliency of the cartilaginous component. Children’s bones have plasticity and can be bent like the proverbial greenstick without fracturing. In the type A Monteggia lesion, for instance, it is conceivable that the ulna bends to the point of fracture, whereas the radius only bends to the point at which the radial head slips under the annular ligament and dislocates anteriorly (Fig. 20-2). It is of interest to note that in most cases requiring open reduction of the radial head, the annular ligament is actually intact. A similar situation may be found with the traumatic isolated dislocation of the radial head that occurs in very young children in which the radius bends just enough for the head and neck to slip under the annular ligament (called nursemaid’s elbow). When trauma is less severe, as in a pulled elbow, the head of the radius has simply slipped into the annular ligament, and there is no actual dislocation. A supination maneuver “screws” the radial head out of the annular ligament, usually with no actual damage to the ligament itself. This combination of generalized laxity, the large cartilaginous component, the lack of osseous stability, and the presence of osseous plasticity as well as numerous secondary centers of ossification and apophyses all contribute to the anachronism of a greater tendency of dislocation of the pediatric elbow joint than seen with other joints.

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FIGURE 20-2

Annular ligament reconstruction using forearm fascia (Boyd technique).

TYPES OF DISLOCATION OF THE RADIAL HEAD CONGENITAL DISLOCATION Congenital dislocation of the radial head is a controversial lesion, because some maintain this lesion does not exist at all and all such appearances are simply traumatic or developmental dislocations. This subject is discussed in more detail in Chapter 13. Here, I reserve the diagnosis of congenital dislocation for that entity in which congenital malformation of the extremity is obvious (Fig. 20-3). When isolated dislocation of the radial head is not accompanied by other congenital lesions, the congenital basis for the lesion cannot be substantiated. The long-standing nature of the dislocation can be inferred from the marked convexity of the radial head associated with elongation of the radial neck (Fig. 20-4).27,28 Congenital dislocation of the radial head may be associated with radioulnar synostosis, the synostosis almost always occurring between the proximal radius and the ulna.32-36 Hypoplasia of the capitellum associated with dislocation of the radial head strongly suggests that the dislocation is congenital. The radiologic appearance of congenital dislocations of the radial head has been emphasized by Miura.37 In congenital dislocations, the posterior border of the ulna is usually concave rather than slightly convex, with the radial head being dome-shaped with no central depression (see Fig. 20-3). Posterior congenital dislocation, which constitutes about 40% of congenital dislocations of the radial head, is associated with an accentuation of the normal convexity of the posterior

border of the ulna. In fact, because we have not been able to diagnose this pathology, at best, we consider this a developmental problem.28

DEVELOPMENTAL DISLOCATION Many instances of developmental or secondary dislocation of the radial head are misinterpreted as being congenital in origin.28 Developmental dislocation is defined as any dislocation of the radial head that results from maldevelopment of the forearm. There are many inherited and acquired disease processes affecting the growth plate of the forearm bones that result in asymmetric growth between the radius and the ulna and subsequent dislocation of the radial head. These include the nail patella syndrome, Silver syndrome, arthrogryposis, Cornelia de Lange syndrome, and cleidocranial dysostosis. Asymmetric growth also occurs in multiple exostoses or diaphyseal aclasis. The ulna is most frequently affected at the distal ulnar growth plate; the radius then overgrows relative to the ulna (Fig. 20-5). Paralysis of the muscles innervated by the C5-6 nerve root, as in a nerve root palsy, also predisposes to a gradual dislocation of the radial head that occurs over a number of years of growth or occasionally in infancy.17 Cerebral palsy also may produce isolated dislocation of the radial head through marked spasticity of the muscles attached to the radius (Fig. 20-6).21 Trauma to the radius or the ulna, resulting in asymmetric growth, may also produce dislocation of the radial head. Fracture of the neck of the radius that has not been corrected adequately may result in the proximal radial epiphysis growing laterally instead of toward the capitellum (Fig. 20-7).20-26

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FIGURE 20-3

A and B, Congenital dislocation of the radial head associated with other congenital malformations of the forearm. Note the rounded convexity of the radial head.

A detailed developmental posterior study at the Mayo Clinic describes several grades, or types, of radial head dislocation with characteristic radiographic appearance (Fig. 20-8). Types II and III are complete dislocations and are more obvious cosmetically but have relatively little functional loss except forearm rotation.28 Type I dislocations commonly are associated with late degenerative arthrosis and consist more of a subluxation than a frank dislocation. However, consistent with the definition of forearm maldevelopment, all types have a previous proximal ulnar bow. There are few indications for operative treatment of developmental dislocation of the radial head. For example, a malunion of the radius and the ulna that is obviously directing the head of the radius laterally, posteriorly, or anteriorly should be corrected with an osteotomy to redirect the proximal radius or the deformed ulna19; otherwise, excision of the radial head can be effective to improve motion, lessen pain, or to improve cosmesis. In patients with cerebral palsy, if the bicipital tendon appears to be subluxating the radial head anteriorly, lengthening the biceps may prevent future dislocation.

Once the dislocation is well established, attempts to relocate the radial head probably should not be made, and the dislocation should be accepted. Future resection of the radial head at skeletal maturity can be performed if the head is cosmetically or functionally a problem. The gradual nature of the dislocation and adjacent changes in the surrounding tissues and bone make this type of relocation of the radial head much more difficult than the acute traumatic injury.26 Relocation of the radial head by shortening the radius and reconstitution of the annular ligament is ineffective.

RADIOGRAPHIC APPEARANCE The radiographic appearance of a long-standing dislocated radial head is characterized by a rounded contour or convexity in contrast to the normal concave appearance (see Fig. 20-4). The posterior border of the ulna also may be concave rather than slightly convex in anterior dislocations of the radial head. Posterior dislocations result in a longer neck with a typical

Chapter 20 Dislocations of the Child’s Elbow

a. Concave head Recent dislocation

b. Convex head Congenital or longterm dislocation

C FIGURE 20-4 Developmental or long-standing dislocation of the radial head. A, Note the rounded appearance of the head, convexity of the articular surface, and narrow neck typical of this deformity. B, Opposite normal elbow. C, Convexity of head develops if the radius is not in contact with the capitellum.

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FIGURE 20-5

A to D, Dislocation of the radial head posterolaterally in a patient with multiple exostoses.

dome-shaped head. Even an isolated traumatic dislocation of the radial head, when it occurs in a very young child, may take on the appearance of a congenital or developmental dislocation with the passage of time. A relative increase in ulnar length in relation to the radius and the wrist is often noted. With posterior dislocation, proximal ulnar bowing also is prominent, and proximal radial migration of the radius may be present.28 The capitellum may be hypoplastic or, occasionally, even absent.38 Other factors characteristic of congenital or developmental radial head dislocations have been reported to be bilaterality of involvement,28 association with other congenital anomalies, familial occurrence, absence of traumatic history, and the presence of the entity in a patient younger than 6 months of age17-24 (see Chapter 13).

NATURAL HISTORY Developmental dislocation of the radial head seldom causes severe pain with anterior dislocation. Patients may complain of clicking or impingement at the ulnohumeral joint with flexion of the elbow. In our experience, this is not seen until adolescence or adulthood.

Posterior dislocation of the radial head typically creates a cosmetic protuberance that also may be a source of pain with excessive elbow motion.28 Aching in the region of the dislocation is common in the older child. A prominent ulna at the wrist and the resultant radioulnar subluxation at the distal end may result in some limitation of motion at the wrist, but discomfort is uncommon. There does not appear to be any progressive loss of motion with further growth, and the joint limitation, if present, remains static.20,28

TRAUMATIC DISLOCATION Solitary dislocation of the radial head is uncommon but occurs much more frequently in younger children. It is essential to differentiate this entity from a developmental dislocation of the radial head that typically is diagnosed incidentally when assessing a minor elbow injury. The history is of limited value in these cases because these children are often young, prone to frequent elbow injuries, and unable to make a reliable contribution to the history. The radiograph, however, is usually diagnostic because it shows the rounded concave appearance of the radial head in the congenital or developmental dislocation (see Fig. 20-4).1-16

Chapter 20 Dislocations of the Child’s Elbow

C FIGURE 20-6

A and B, Long-standing dislocation of the radial head in a child with cerebral palsy. The elongation of the neck and convexity of the head indicate the presence of a prolonged dislocation. C, Spasticity or contraction of the biceps tendon may contribute to isolated dislocation of the radial head in children.

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TREATMENT OF ACUTE ANTERIOR DISLOCATION CLOSED REDUCTION If the child is seen within 3 weeks of the injury, a closed reduction may be achieved. Direct pressure over the radial head with gradual flexion of the arm and immobilization in a flexed position of more than 100 degrees is usually successful. If the radial head has been dislocated for several weeks and if the annular ligament has become entrapped, preventing adequate reduction, an open reduction may have to be performed. If the radial head can be reduced but is not stable, a Kirschner wire fixation to the ulna may be effective. Driving a pin across the elbow joint through the capitellum and into the radial head is not recommended because these wires often break, making removal difficult. Breakage occurs because it is virtually impossible to immobilize the child’s elbow completely, and minor motion, even when in a cast, may result in a fatigue fracture of the wire. The elbow joint will then have to be opened unnecessarily to remove the fractured pin. FIGURE 20-7

A and B, A child sustained a fracture of the ulna and neck of the radius that healed in malunion. Four years later, the radial head is dislocating laterally owing to malposition of the proximal radial epiphyseal plate.

CLINICAL FEATURES OF ISOLATED ANTERIOR DISLOCATION With trauma, children who have sustained an anterior dislocation of the radial head demonstrate an unwillingness to use the arm. Careful examination of the extremities and the radiograph may reveal some ulnar bowing. This is analogous to a Monteggia fracture-dislocation except that the ulna is simply bowed rather than fractured. Radiographically, a line drawn through the shaft of the radius and the radial head will not intersect the capitellum when the radial head is dislocated (see Fig. 20-1). Children who have been subjected to child abuse may present with this particular injury, and again, the history will be difficult to elicit.

OPEN REDUCTION Triceps Fascial Reconstruction The technique of open reduction of an anterior dislocation of the radial head in children described by LloydRoberts and Bucknill20 is one I have used with success. This consists of using the lateral portion of the tendon of the triceps for reconstruction of the annular ligament (Fig. 20-9A). A posterolateral incision is preferred rather than a posterior incision, which may disorient the surgeon to the position of the radial head. The triceps tendon is identified, and a long (10-cm) strip is removed from the lateral margin, ensuring attachment at the distal ulnar insertion. The tendon is increased in length by continuing the dissection through the periosteum to a point opposite the neck of the radius, where it is then passed around the neck and sutured to itself and the ulnar periosteum with enough tension to hold the radial head in place. A Kirschner wire is then passed through the ulna into the radius to ensure solid fixation until the tendon has healed (see Fig. 20-9B).18 The extremity is kept immobilized in an above-elbow plaster cast for 6 weeks; gradual mobilization is begun at 6 weeks after the Kirschner wire has been removed. If there is any difficulty in reducing the radial head, careful inspection of the joint capsule may reveal some infolding or tissue interposition, which may have to be excised.

Chapter 20 Dislocations of the Child’s Elbow

I

A

II

B

III

C FIGURE 20-8

The Mayo classification of posterior radial head instability. A, Type I is subluxation with characteristic radial head elongation and is associated with a poor functional result. B, Type II is complete dislocation but without subluxation. These patients typically have minimal pain but moderate loss of forearm rotation. Forearm prominence may be noticed C, Dislocation with posterior subluxation, type III, causes a marked cosmetic deformity but little functional impairment. Surgery is performed only for cosmetic reasons.

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X A

B

FIGURE 20-9

A, Repair of radial head dislocation by reconstruction of annular ligament using triceps fascia (Lloyd Roberts-Bucknill technique). B, A Kirschner wire passed through the capitellum into the radial head (left) is not recommended owing to danger of pin fatigue and breakage. The radial head can be safely held in the reduced position by a pin across the radius and ulna (right).

Specific care must be exercised when exposing the neck of the radius in a child. Unlike the adult, the radial nerve may be only a fingerbreadth below the head of the radius rather than the classic two fingerbreadths that is often referenced.

Fascial Reconstruction of the Annular Ligament If inadequate, the annular ligament may be reconstructed. A strip of fascia is dissected from the forearm muscles but is left attached to the proximal ulna. The length of this fascial strip should be about 5 inches by 1/2 inch. It is passed around the neck of the radius, proximal to the tuberosity and distal to the radial notch of the ulna, and is brought around and fastened to itself with nonabsorbable sutures (see Fig. 20-9). Care should be taken to ensure that the length of this fascial strip is adequate. Cross-radioulnar pin fixation for 4 weeks is reassuring.

UNTREATED ANTERIOR DISLOCATION OF THE RADIAL HEAD A child with a long-standing anterior dislocation of the radial head actually may have good elbow function. The range of motion is usually functional, although the extremes of flexion and extension are usually limited by 20 or 30 degrees. In our experience, pain may develop at a later date, usually the fourth decade. The cosmetic deformity is also a concern, and the elbow may appear somewhat deformed, especially in a small, thin arm. Excision of the radial head at skeletal maturity is generally successful, and the radius does not migrate proximally.

COMPLICATIONS Relocation of an acute dislocation of the radial head in a child is usually successful, and recurrence is uncommon. If not reduced, limited motion and cosmetic deformity ensue. The dislocated radial head may also result in a relative shortening of the radius compared with the ulna, with subsequent subluxation at the radioulnar joint at the wrist. As a general rule, the radial head should not be excised in a child because this may further aggravate shortening of the radius by eliminating the proximal radial growth plate, which contributes about 30% of the final radial length. If there is pain or a grotesque appearance when the child is near skeletal maturity, the radial head is easily removed. In neglected patients, excision of the radial head may allow improved flexion and rotation and may alleviate complaints of pain and discomfort.28

PEDIATRIC MONTEGGIA FRACTURE DISLOCATION The Monteggia injury is uncommon in children but by no means rare. In the 5-year period from 1978 to 1982 at the Winnipeg Children’s Hospital, 33 children were treated for a variety of Monteggia lesions. The true incidence of this fracture-dislocation is unknown, but it is more common than is generally appreciated. Olney and Menelaus53 reported 102 children with acute Monteggia lesions over a 25-year period.

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307

ETIOLOGY The most common cause of dislocation of the radial head associated with an ulnar fracture in childhood is a hyperextension injury,44,62 followed by a hyperpronation injury.45 In hyperpronation, Bado39 pointed out that the bicipital tuberosity is posterior, thus predisposing the proximal radius to the greatest force during violent contraction of the bicipital tendon. In young children, the force generated by the biceps is less than that in the adult, and this mechanism probably is significant only in older children. A direct blow over the posterior proximal ulna will produce a Monteggia lesion with anterior dislocation of the radial head, but this is an uncommon mechanism in children. In our experience, this lesion is most frequently produced by a hyperextension injury. Further support for this theory is the observation that, in open type C injuries, the proximal ulnar fragment pierces the skin on the volar ulnar aspect of the forearm. This would not be possible if the arm were in full pronation because of imposition of the radius. Because of the plasticity of the forearm bones, the radial head and neck may slip under the annular ligament and dislocate as the shaft of the radius bends. Indeed, many of the isolated traumatic dislocations of the radial head are undoubtedly variations of the Monteggia46-48 (Monteggia equivalent), in which the ulna has simply bent but not fractured. The radial shaft is bent to the extent that the head and neck are slipped from within the annular ligament, resulting in an apparent isolated dislocation of the radial head.30,43

CLASSIFICATIONS Classifications of the Monteggia lesion are based largely on the injury in adults39 (see Chapter 27). Because of differences in the configuration of the injury in childhood, the following pediatric classification is suggested to include dislocation of the radial head associated with the plasticity of the forearm bones in childhood (Fig. 20-10).

CLASSIFICATION OF PEDIATRIC MONTEGGIA LESIONS Type A: Anterior dislocation of the radial head anterior bowing of the ulna (Fig. 20-11). Type B: Anterior dislocation of the radial head greenstick fracture of the ulna (Fig. 20-12). Type C: Anterior dislocation of the radial head transverse fracture of the ulna (Fig. 20-13). Type D: Posterior dislocation of the radial head bending or fracture of the ulna (Fig. 20-14).

with with with with

A Anterior bend

B Anterior greenstick

C

Anterior complete

E

Lateral

D Posterior

FIGURE 20-10 Classification of the pediatric Monteggia fracture dislocation: types A through E.

Type E: Lateral dislocation of the radial head with fracture of the ulna (Fig. 20-15). Types B and C are the most commonly encountered Monteggia lesions in children.51

CLINICAL DIAGNOSIS Like Monteggia himself, who described this injury initially in a young woman in 1814, long before the advent of radiography, most physicians today should be able to identify the clinical configuration in those seen early, before swelling has occurred (see Fig. 20-15). The dislocation of the radial head is often evident on inspection of the lateral aspect of the elbow joint. Angulation of the ulna, whether fractured or not, necessitates careful appraisal of the position of the radial head. Dislocation of the radial head is frequently missed by those who treat pediatric elbow injuries only occasionally.52-58 A line drawn through the shaft and the neck of the radius should intersect the capitellum in all views taken (see

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FIGURE 20-11 A and B, Ulnar bend with lateral dislocation of the radial head, a type A Monteggia fracture dislocation.

FIGURE 20-12 A and B, Type B Monteggia fracture associated with a greenstick fracture of the ulna and anterior dislocation of the radial head.

Chapter 20 Dislocations of the Child’s Elbow

Fig. 20-1). If it does not, dislocation of the radial head is highly suspect. In contrast to the lesion in adults, overlap of the ulnar fragments is not a prerequisite for dislocation of the radial head in a child. Disruption of the forearm parallelogram may occur as a result of ulnar bend when the radial head slips out of the annular ligament. It is wise

FIGURE 20-13 Anterior dislocation of the radial head with transverse fracture of ulna.

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to obtain anteroposterior and lateral views of the elbow joint in all fractures of the ulna. The apex of the ulnar bend or angulation is always in the direction of the radial head dislocation.51-65

TREATMENT In contrast to the adult, the Monteggia injury in children usually can be treated by closed methods.31 Pressure directed over the dislocated radius usually will result in a stable ulnar reduction, provided that immobilization is imposed with the elbow flexed more than 90 degrees in types A, B, C, and E lesions. Supination assists in minimizing biceps pull. In the uncommon type D Monteggia lesion with posterior dislocation of the radial head, stability is obtained with extension, not flexion, of the elbow. As long as the radial head is reduced and stable, angulation of the ulna of as much as 15 degrees can be accepted. Remodeling of this angulation will occur with further growth. In children, stable reduction of the radial head is the first priority. A supination-pronation maneuver may facilitate repositioning of the annular ligament, which is seldom completely torn. If it is impossible to obtain a stable reduction of the radial head, I approach the radial head through a Kocher incision and reapproximate the annular ligament around

FIGURE 20-14 A and B, Posterior lateral dislocation of the radial head with bending or fracture of the ulna.

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the neck. If stability is still precarious or if the annular ligament has had to be reconstituted, I recommend internal fixation of the radius to the ulna with a Kirschner wire (Fig. 20-16A). As noted earlier, I would caution against maintenance of the reduction by a wire inserted through the capitellum and into the radial head. Fatigue fracture is always a possibility (see Fig. 20-8B). If the ulna is unstable in the older child, an open reduction with plate fixation may be necessary, but in my experience, this is seldom required in those under 10 years of age.58

NERVE INJURY ASSOCIATED WITH MONTEGGIA LESIONS Anterior dislocation of the radial head may result in a traction injury to the posterior interosseous nerve as it passes dorsolaterally around the proximal radius to enter the substance of the supinator muscle mass between the superficial and deep layers (see Fig. 20-16B).46,60 Compression of the posterior interosseous nerve also may be aggravated by the fibrous arcade of Frohse, a firm fibrous band at the proximal edge of the supinator muscle.59 In children, nerve injury is less common than in adults, and recovery is the rule in closed injuries. In a large series of 102 Monteggia fractures, Olney and Menelaus53 found a 10% incidence of nerve injuries, 6% involving the posterior interosseous nerve and 3% involving the radial nerve. All their nerve injuries healed completely within 6 months.

THE MISSED MONTEGGIA LESION

FIGURE 20-15 Monteggia fracture with lateral dislocation of the radial head. A, Clinical appearance. B and C, Radiologic appearance.

The dislocated radial head that is noticed only after the ulna has healed is a common error made by less experienced clinicians and in some instances the initial injury has almost been forgotten (see Fig. 20-16D). Some confusion may occasionally arise in connection with the congenital dislocated radial head, but in general, the contour of the radial head should be diagnostic— the congenital lesion having a rounded convex head whereas the recently dislocated radius usually has a concave appearance. It can be appreciated that the younger the child, the more difficult it will be to make this interpretation, owing to the large cartilaginous component of the proximal radius.40-44,46,50

DISLOCATION-SUBLUXATION OF THE RADIAL HEAD FOLLOWING MALUNION OF A RADIAL NECK FRACTURE Fractures of the radial neck in children that have occurred after the age of 6 or 7 years may, if unreduced, result in

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311

C FIGURE 20-16 A and B, Preferred radioulnar pinning to hold the radial head in place subsequent to late open reduction of a Monteggia fracture dislocation and annular ligament repair. C, Injury to the posterior interosseous nerve may occur in the Monteggia fracture with anterior dislocation of the radial head. D, Missed dislocation of the radial head in an unappreciated Monteggia fracture with greenstick fracture of the ulna.

a subluxation (see Fig. 20-7). When neck angulation is more than 45 to 50 degrees, the growth plate becomes redirected laterally or posterolaterally. If there is not enough remodeling to allow the growth plate to reattain its normal transverse anatomy, increased prominence of the radial head ensues. As the child grows, pain may be experienced, as well as irritation, cosmetic deformity, and, to a lesser extent, limitation of supination and pronation. This can be avoided by ensuring that the angulation of the radial neck is reduced to less than 45 degrees by closed or open reduction.63

When associated with malunion of the ulna radial head, instability may necessitate osteotomy of the ulna and open reduction of the radial head. It is of course always prudent to attempt a closed reduction of the radial head if the injury has occurred recently (i.e., within 2 months) because the ulna may still be straightened. Usually, however, in the missed Monteggia lesion, an open reduction of the radial head will be necessary, and in this instance, it will almost certainly be necessary to reconstitute the annular ligament—with the ligament itself, if possible, with fascia obtained from the triceps,

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or by using the Bell-Tawse procedure.42,44,49 Shortening of the radius may be necessary to permit reduction. Internal fixation with Kirschner wires through the radius to the ulna is advisable. Relocation of the radial head should be attempted in children younger than 6 years of age.18 In older children in whom the lesion has been present for more than 1 year, it may be advisable to accept the dislocation because this is compatible with excellent function in most instances. A modified technique for reconstruction of the annular ligament has been reported by Peterson and Seel,56 which appears effective in patients with long-standing radial head dislocations. If the radial head becomes cosmetically or functionally disabling, excision is performed as needed when skeletally mature. Removal of the radial head is avoided until skeletal maturity since 30% of radial growth occurs at the proximal radial epiphysis.

PULLED ELBOW SYNDROME Nursemaid’s elbow, or pulled elbow syndrome, has been recognized since early in this century.124 Some children seem to be particularly prone to this injury, and for them, even minor pulls on the arm result in the typical pain and failure of elbow motion that is always of concern to parents (Fig. 20-17A).123,124

ETIOLOGY Subsequent to a longitudinal pull on the forearm, the radial head is pulled down into the annular ligament (see Fig. 20-17B). This results in inability to rotate the radial head without considerable discomfort. Usually, the annular ligament is not torn; however, as the child becomes older, the annular ligament is undoubtedly partially torn, which accounts for the persistence of symptoms for several days even after the reduction. At one time, it was thought that the radial head in a child was smaller in relation to the neck than in adults or older children, and thus, subluxation of the radial head into the annular ligament was more common.125 Studies by Salter and Zaltz129 and Mehta127 have shown that, even in infants, the relative proportion of radial head diameter to neck diameter is similar to that of adults. The pulled elbow syndrome is most common between the ages of 6 months and 3 years, becoming less common as the radius grows in size and becomes more ossified.126 A reasonable explanation for pulled elbow is simply the generalized ligamentous laxity of the elbow that exists at this age and the resiliency imparted to the radial head by the almost entirely cartilaginous structure.122,123 A longitudinal pull with accompanying pronation of the forearm screws the radial head down into the annular

ligament, and the larger head then becomes caught as if in a Chinese finger trap (see Fig. 20-17B).

CLINICAL APPEARANCE A child with the pulled elbow syndrome complains primarily of pain and failure to move the elbow, and there may or may not be a typical history of a longitudinal pull. The infant may well go about his or her normal play activities and is comfortable as long as no one attempts to move the elbow. The child keeps the arm in pronation and expresses discomfort and anxiety if anyone attempts to move the elbow or to pronate or supinate the forearm. Radiographs are singularly nondiagnostic and are sometimes misinterpreted because it is impossible to position the limb properly.124-129 However, the technicians, in attempting to obtain good anteroposterior and lateral films of the elbow, may inadvertently reduce the subluxation by supinating the forearm, and the child returns from the Radiology Department content and moving his or her elbow normally.

MANAGEMENT Reduction of the pulled elbow is usually simple, consisting of a supination motion with the elbow flexed. A click is often felt and sometimes even heard. As the radial head is “screwed up” into the annular ligament, the ligament slips down over the head into its normal position around the neck with a snap. In younger children, resumption of normal activity often ensues in minutes; however, in the older child, the elbow may remain tender, probably owing to small tears within the annular ligament. If pain persists, immobilization of the arm in a plaster cast or splint for a week or so is curative. Other than emotional upset, there are no long-term sequelae from the pulled elbow syndrome, because in some children, its frequent recurrence is a cause of concern to patient and family. In such a case, it is often worthwhile to explain precisely what is happening and demonstrate how to reduce the pulled elbow to avoid visits to the emergency department. Seldom is open repair of the annular ligament necessary, because even in the most recalcitrant circumstances, time and growth always cure this type of instability.

TRAUMATIC DISLOCATION OF THE ELBOW MECHANISM OF THE DISLOCATION As discussed earlier, the elbow joint in a child is basically a ligamentous structure in which only a small portion of cartilaginous stability is imparted by the ulna. With a fall on the outstretched hand the downward force on

Chapter 20 Dislocations of the Child’s Elbow

313

A

B Normal anatomical reduction

Pronation plus traction

Supination reduction

the fixed forearm is considerable. An associated valgus or varus force created by the body falling over the fixed elbow occurs (Fig. 20-18). The forearm is typically in pronation during this time. The coronoid process may be fractured (Fig. 20-19). The valgus force of the body rotating over the fixed elbow accounts for the frequent

FIGURE 20-17 A, Some causes of pulled elbow syndrome in small children. B, Pathophysiology of the pulled elbow syndrome.

avulsion of the medial epicondylar apophysis (Fig. 20-20).71,83 If the body falls over the elbow medially instead of laterally, a varus force is exerted, and the lateral epicondyle of the humerus or the lateral condyle may be avulsed84 (Fig. 20-21). Occasionally, as in a fall from a height, the forces may be such that the valgus

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DISLOCATION FORCES ABOUT THE ELBOW Varus force

Coronoid process sheared off

Varus rotatory

Valgus rotatory

cal

Lateral epicondyle avulsion

Ver ti

Anteroposterior

Ground reaction force Valgus force Olecranon fracture

Lateral

Coronoid process Medial epicondyle avulsion

FIGURE 20-18

children.

Valgus

Radial neck fracture

Mechanism of dislocation of the elbow in

force may disrupt the medial apophysis, and the posterolateral dislocation may also avulse the lateral epicondyle, resulting in elbow instability on both the ulnar and the radial sides of the joint. The radius and the ulna seldom separate owing to the strong interosseous membrane, although instances of divergent dislocations with tearing of the interosseous membrane have been reported.75,81,86,96 Less commonly, traction injuries may result in elbow dislocation.80 Occasionally, in falls from a height, the valgus force exerted on the elbow joint may result in a fracture of the neck of the radius and the olecranon process (Fig. 20-22). When the arm is in marked extension, the capitellum also may be fractured. Associated fractures of the distal radius and ulna occasionally occur (Fig. 20-23). Along with the other associated trauma, capsular tearing is responsible for the prolonged stiffness that often follows dislocation of the elbow. The capsular attachment to the ulna and humerus is frequently torn.

SPONTANEOUS REDUCTION OF THE DISLOCATED ELBOW Spontaneous reduction of a dislocated elbow in children is common. Often the child will present to the emergency department with a history of a fall, the only

FIGURE 20-19 A and B, Fracture of coronoid process of olecranon associated with posterior dislocation of the elbow.

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315

FIGURE 20-20 A and B, Fracture of radial neck with avulsion of the medial epicondyle, which has remained intra-articular following spontaneous reduction of the elbow dislocation.

FIGURE 20-21 A and B, Dislocation of the elbow associated with fracture of the lateral condyle of the humerus. The radial head maintains its relationship with the displaced capitellum.

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FIGURE 20-22 A and B, Dislocation of the elbow with valgus force resulting in fracture of the olecranon, radial neck, and medial epicondyle, which has remained intra-articular following spontaneous reduction.

physical findings being a swollen, boggy elbow and no obvious radiographic evidence of any injury. However, if one looks carefully at the radiograph, signs of previous dislocation may be present (Fig. 20-24). Of particular note is fracture of the coronoid process (Fig. 20-25), which indicates that the elbow has been transiently subluxed. Sometimes, at reduction the humerus may cause a type I or II fracture through the epiphyseal plate of the proximal radius, resulting in posterior displacement of the radial epiphysis on reduction (Fig. 20-26).

DIFFERENTIAL DIAGNOSIS OF POSTERIOR DISLOCATION

FIGURE 20-23 A and B, Fracture of distal radius associated with dislocation of the elbow.

The child with dislocation of the elbow is severely incapacitated with pain and deformity. The differential diagnosis basically consists of distinguishing a dislocation from a supracondylar fracture, a lateral condylar fracture, and, in the younger child, a transcondylar fracture of the humerus (Fig. 20-27).92 The elbow will be painful and swollen, and depending on how soon the child is seen after the injury, the posterior deformity may be either obvious or masked by swelling if several hours have passed. The child is always extremely apprehensive

Chapter 20 Dislocations of the Child’s Elbow

and will not allow anyone under any circumstances to move the joint. In my experience, the commonly stated rules of lining up the triangular relationship among the medial epicondyle, lateral epicondyle, and olecranon are not of much practical value in this situation. One can sometimes feel a gap superior to the displaced olecranon, indicating that a posterior dislocation has occurred. The humeral condyles can also be palpated anteriorly. The supracondylar

Avulsion of coronoid tip

Intra-articular Type 1 fracture of medial epicondyle radial epiphysis

FIGURE 20-24 Fractures about the elbow in children indicative of spontaneous reduction of an elbow dislocation.

317

fracture is often difficult to differentiate from a posterior dislocation of the elbow, especially if presentation is late and considerable swelling has occurred to obscure the abnormal anatomy. Excessive examination and movement of such an elbow should be avoided because it serves only to make the child more apprehensive and less cooperative. The neuromuscular examination of the extremity may be difficult but often can be performed simply by observation once the confidence and cooperation of the child have been obtained. Sensation then can be gently tested in the three major nerve distributions, including the anterior and posterior interosseous divisions. It is essential, of course, to assess the neurologic and vascular condition of the limb in the Emergency Department. The child should be encouraged to make the “O” sign with the index finger and thumb. If this cannot be done, injury to the anterior interosseous nerve has occurred, causing paralysis of the flexor pollicis longus. Images are diagnostic today. Dislocation of the elbow is very rare in children younger than the age of 2 years, and transcondylar fracture of the humerus should be suspected (see Fig. 20-25). This may be difficult to differentiate from a posterior dislocation, and confirmation may require special images.68-74,76,79,82 Radiographs should be carefully examined for associated fractures aside from the dislocation. A careful

FIGURE 20-25 A and B, Avulsion fracture of tip of coronoid process following dislocation of the elbow. The brachialis muscle often avulses a small portion of the coronoid process; when present, this is pathognomonic of a previous elbow dislocation.

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A

FIGURE 20-26 A, Type I fracture of the proximal radial epiphysis with posterior displacement occasionally occurs in posterior dislocation of the elbow if reduction is forceful. B, Fracture of neck of radius secondary to dislocation of the elbow with forceful spontaneous reduction.

FIGURE 20-27 Transcondylar fracture of the humerus in infancy may be misdiagnosed as a dislocation of the elbow. Arthrography or computed tomography scan is diagnostic.

Chapter 20 Dislocations of the Child’s Elbow

appraisal of the coronoid process, the radial neck, the olecranon, and the medial and lateral epicondyles should be carried out.67,77,78,84 If the child is over 5 years of age and the medial epicondyle is not present, a radiograph of the other elbow should be inspected to make sure that it is ossified. If the medial epicondyle cannot be found on the radiograph of the dislocated elbow, it must be assumed that it is obscured by its intra-articular position (see Fig. 20-20).66,71,89-95 An injury to the radial epiphysis may occur when the elbow is forcibly reduced. This may even occur at the time of the injury; for example, when a direct blow to the elbow, following the original dislocation that was sustained by a fall on the outstretched hand, causes reduction. The direct force on the radial head results in a type I fracture through the proximal radial epiphysis with posterior displacement (see Fig. 20-26). It is essential to emphasize that many children present to the emergency department with simply a swollen, boggy elbow joint and a history of a fall. In such cases, one can assume, especially if there is radiographic evidence of avulsion of the coronoid process or of the medial epicondyle, that this elbow has been dislocated and has spontaneously reduced.

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bined with some anterior pressure over the prominent olecranon is usually successful, usually with an audible and palpable clunk (Fig. 20-28). Occasionally, in older children, the coronoid process becomes locked behind the humerus. In this instance, the arm should be put in extension and a muscle relaxant administered; with traction and good firm thumb pressure over the olecranon, the elbow usually can be reduced. Hyperextension to free the coronoid is hazardous, especially if vascular insufficiency is already present, because it places more stress on the brachial artery, which may be tented over the distal end of the humerus. Once the elbow is reduced, the integrity of the medial and lateral collateral ligaments should be tested. Furthermore, a smooth arc of motion should be demonstrated to ensure no fragment, particularly the medial epicondyle, is caught within the joint. If the joint does not move freely or has a spongy feel to it, a mechanical problem with reduction exists. The reduction should always be checked radiographically, especially with any associated fracture.85,94,97 Aspiration of the joint is recommended to assist in resolving the hematoma and improving joint motion after reduction. Using a local anesthetic may be helpful in the older patient.

TREATMENT OF POSTERIOR DISLOCATION Posterior dislocation of the elbow is a painful, terrifying experience for a child, and the limb should be put at rest with a splint as soon as possible in the emergency department with minimal manipulation of the extremity. No child should ever be sent for radiographs without adequate splintage. The dislocation demands early treatment and, of course, if there is any vascular insufficiency, immediate treatment. Occasionally, in a very cooperative older child, the elbow may be reduced in the emergency department. The instillation of local anesthetic into the joint itself often facilitates this maneuver. Turning the child prone with the arm dangling over the stretcher facilitates the application of some pressure over the olecranon, and this, combined with gravity or slight traction on the dangling limb, may allow the dislocation to be quickly and traumatically reduced.87 If there is an associated fracture of the medial epicondyle, the radial neck, or the olecranon, this maneuver should be avoided. In our experience with children younger than age 12, it is best to proceed with a general anesthetic for complete relaxation, ideally within 6 hours of the trauma. It is not appropriate to allow the child to wait overnight because massive edema may occur, which is extremely uncomfortable for the child and leads to stiffness. Once the child has been anesthetized, it is usually a simple matter to reduce an uncomplicated posterior elbow dislocation. Gentle traction on the forearm com-

MEDIAL EPICONDYLAR ENTRAPMENT If it is known that the medial epicondyle is trapped within the joint, then during the reduction, a valgus strain is placed on the elbow. With flexion of the wrist this may allow the attached flexor muscle mass to pull the trapped fragment out of the joint. Occasionally, this

FIGURE 20-28 The author’s preferred technique for reducing a posterior dislocation of the elbow joint in children.

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Part IV Conditions Affecting the Child’s Elbow

may yield an anatomic or nearly anatomic position. If the medial epicondyle is displaced more than 1 cm, it should be pinned back in place because it will add stability to the elbow subsequent to the dislocation and allow stable elbow motion to occur within 3 to 4 weeks. In children younger than the age of 5, when the medial epicondyle is not ossified, any springiness in the elbow joint subsequent to the reduction indicates an intraarticular position of the medial epicondyle. Ultrasonographic evaluation of the elbow might be helpful in confirming the presence of an intra-articular fragment.74 If the medial epicondyle cannot be removed from the joint with manipulation, it must be removed surgically. The elbow is approached through a medial incision. The flexor muscle mass initially appears to be anatomically intact as it disappears into the joint; however, with valgus force and gentle pull on the muscle mass, the attached fragment can be removed from the joint, and the capsule can be repaired. The fragment then should be reattached to the distal medial humerus. Care should be taken not to injure the ulnar nerve. If there is any concern about this, the nerve should be identified and retracted with tapes until the repair has been completed.66,89,95,109

POSTOPERATIVE MANAGEMENT Following reduction of the elbow, the joint should be immobilized at 90 degrees with slight forearm supination. Flexion is especially important if there has been a coronoid process avulsion. This allows the triceps to tighten posteriorly, acting as a dynamic splint for the elbow, and also helps prevent the ulna from slipping backward into the dislocated position.

This is an extremely rare type of dislocation that results from tearing of the interosseous membrane. Although I have never treated one of these dislocations, medial and lateral pressure over the divergent radius and ulna to align the forearm bone before reducing it as a simple posterior dislocation has been described.75,81,96

Divergent Dislocation

COMPLICATIONS OF ELBOW DISLOCATION Complications from simple dislocations of the elbow are uncommon in children, especially when compared with this injury in the adult. Joint Stiffness As in adults, joint stiffness is the most common problem encountered after dislocation of the elbow in children. The child and his or her parents must be advised that joint motion may be lost as a result of the injury. In older children, fully complete extension may never be recovered, although the loss of the last 5 to 10 degrees of extension is not accompanied by any marked functional deficit. Elbows in children should not be immobilized longer than 4 weeks, and exercises after injury should be primarily active; passive motion should be avoided. Seldom is manipulation or passive physiotherapy required for joint stiffness after a dislocation of the elbow; this type of treatment often delays recovery because it is accompanied by further joint irritation, capsular tearing, and hematoma formation. A year may be required to regain full motion in the child’s elbow, the child being his or her own best physiotherapist. Management of the stiff elbow in the child is discussed in detail in Chapter 21.

Myositis ossificans is an uncommon complication of a simple dislocation of the elbow joint in children unless it is accompanied by a crush injury, head injury, major trauma, or multiple manipulations. Myositis ossificans may bridge the joint involving the brachialis muscle. The ossific lesion can be excised once it is mature, however, but recurrence is still possible.110

Myositis Ossificans

OTHER TYPES OF ELBOW DISLOCATION Anterior dislocation of the elbow in children is uncommon and usually is the result of severe direct trauma to the posterior aspect of the proximal forearm. This may be associated with a fracture of the olecranon. Reduction should be accomplished by direct pressure anteriorly over the dislocated radius and ulna, together with gentle traction on the forearm to allow the olecranon to slide beneath the humerus.72,88

Anterior Dislocation

Purely medial or lateral dislocations are extremely rare and probably do not exist without an anterior/posterior injury. Longitudinal traction may be all that is required for reduction. However, if the joint deviates considerably to either side, appropriate pressure over the medial or lateral aspects to align the elbow prior to reduction often facilitates reduction.77,85

Medial or Lateral Dislocation

Nerve injuries are uncommon in simple posterior elbow dislocations in children. The ulnar nerve is most frequently involved.80,117 The common posterolateral dislocation of the elbow results in a stretch on the ulnar nerve. The median and, rarely, the radial nerves also may suffer neuropraxic injuries secondary to posterior dislocation of the elbow. The median nerve may be vulnerable to entrapment within the joint subsequent to reduction of the elbow dislocation. Although rare, this type of entrapment has been reported only in children, and diagnosis is frequently delayed. It should be suspected when signs of Nerve Injuries

Chapter 20 Dislocations of the Child’s Elbow

FIGURE 20-29

Course of median nerve lying entrapped posterior to the medial epicondyle. (Redrawn from Matev, I.: Radiological sign of entrapment of the median nerve in the elbow joint after posterior dislocation. J. Bone Joint Surg. 58:353, 1976.)

median nerve injury or pain accompany avulsion of the medial epicondyle; in such instances, the nerve usually lies “posterior” to the medial epicondyle (Fig. 20-29).98,102,105,108 As emphasized by Green,101 in an excellent review of this subject, persistent pain or increasing median nerve dysfunction should alert one to the possibility of nerve entrapment. A late clinical sign of entrapment is persistent limitation of elbow motion; a late radiologic sign of median nerve entrapment is depression of the cortex of the distal humerus just proximal to the medial epicondyle, where the median nerve passes behind the humerus.105,106 This is termed Matev’s sign (Fig. 20-30). Immediate exploration should be undertaken once the diagnosis of nerve entrapment has been made. If the nerve is functionally intact, as demonstrated by nerve stimulation, simple removal of the nerve from the joint is sufficient treatment. If the nerve is obviously severely damaged, crushed, or scarred and nonfunctional, resection of the damaged section with end-to-end reanastomosis is recommended.99,107

321

FIGURE 20-30 Median nerve entrapment 3 months after injury. The arrow points to a cortical depression with interruption of periosteal reaction. (From Matev, I.: Radiological sign of entrapment of the median nerve in the elbow joint after posterior dislocation. J. Bone Joint Surg. 58:353, 1976.)

Injury to the brachial artery to the extent of complete occlusion is not commonly observed in dislocations of the elbow in children. The brachial artery may be stretched over the distal humerus, and if the force is sufficient, damage to the artery may occur. This is evident by the usual signs of vascular impairment, which then demand exploration of the artery. The elbow should always be reduced before making a final assessment of the vascular status of the limb because it simply may be occluded subsequent to the elbow deformity.100,103,104,106 In assessing vascular integrity in a child’s arm, caution must be advised in putting too much faith in capillary filling. Collateral circulation may be sufficient to provide excellent capillary filling but insufficient to adequately vascularize the extremity. Vascular Injury

Recurrent Dislocation of the Elbow Recurrent dislocation of the elbow in children is very uncommon, as is an unreduced dislocation.69 Today, recurrent dislocation is known to occur with a deficient lateral ulnar

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collateral ligament.93 Inadequate treatment, in which the elbow has been kept flexed at less than 90 degrees, especially when associated with a fracture of the coronoid process, may result in redislocation of the elbow and reinjury and recurrent dislocation.111-121 It is uncommon to experience recurrent dislocation. Uncommonly, this may be secondary to severe generalized ligamentous laxity, as occurs in Ehlers-Danlos syndrome. In a review of the Ehlers-Danlos syndrome by Beighton and Horan,111 19 of 100 patients suffered dislocations of one or more joints, with three having dislocation of the elbow. Recurrent dislocations of the elbow were reported by Rames and Strecker120 in a 9year-old girl who subsequently required a repair of the lateral capsule and ligamentous structures with drill holes through the lateral epicondyle to firmly anchor the capsule, as described by Osborn and Cotterill.119 Recurrent subluxation of the elbow recently was described by O’Driscoll and Morrey,118 who noted the etiology as deficiency of the lateral ulnar collateral ligament. Of note, like the shoulder, recurrence of the elbow dislocation is greater in adolescents than in adults. This may be treated successfully with an orthosis designed to block the last 15 degrees of extension associated with muscle strengthening to protect and stabilize the elbow. If this fails, surgery to reconstruct the lateral collateral ligament complex is required.

SUMMARY Dislocations about the elbow are common in children. Because they often accompany fractures in the region of the joint, care must be taken to examine the environs of the elbow systematically for evidence of skeletal injury coexisting with the dislocation. Particular care should be exercised to ensure that the radial head is in its proper relationship with the capitellum. Because most problems encountered in elbow dislocations in children are the result of missed diagnoses of associated injuries, the value of a thorough clinical and radiographic examination of the elbow cannot be overemphasized.

References TRAUMATIC DISLOCATION OF THE RADIAL HEAD 1. Beddow, F. H., and Corckery, P. H.: Lateral dislocation of the radial humeral joint with greenstick fracture of the upper end of the ulna. J. Bone Joint Surg. 42B:782, 1960. 2. De Lee, J. C.: Transverse divergent dislocation of the elbow in a child. J. Bone Joint Surg. 63A:322, 1981. 3. Heidt, R. S., and Stern, P. J.: Isolated posterior dislocation of the radial head. Clin. Orthop. Rel. Res. 168:136, 1982.

4. Hudson, D. A., and DeBeer, De. V.: Isolated traumatic dislocation of the radial head in children. J. Bone Joint Surg. 68B:378, 1986. 5. Kirkos, J. M., Beslikas, T. A., and Papavasiliou, V. A.: Posteromedial dislocation of the elbow with lateral condylar fracture in children. Clin. Orthop. Rel. Res. 408:232, 2003. 6. Lincoln, T. L., and Mubarek, S. J.: “Isolated” traumatic radial head dislocation. J. Pediatr. Orthop. 14:454, 1994. 7. Macias, C. G., Wiebe, R., and Bothner, J.: History and radiographic findings associated with clinically suspected radial head subluxations. Pediatr. Emerg. Care 16:22, 2000. 8. Pudas, T., Hurme, T., Mattila, K., and Svedstrom, E.: Magnetic resonance imaging in pediatric elbow fractures. Acta Radiol. 46:636, 2005. 9. Schubert, J. J.: Dislocation of the radial head in the newborn infant. J. Bone Joint Surg. 47A:1010, 1965. 10. Stelling, F. H., and Cote, R. H.: Traumatic dislocation of the head of the radius in children. J. A. M. A. 160:732, 1956. 11. Storen, G.: Traumatic dislocation of the radial head as an isolated lesion in children. Acta Clin. Scand. 116:144, 1958. 12. Vesely, D. G.: Isolated traumatic dislocation of the radial head in children. Clin. Orthop. Rel. Res. 50:31, 1967. 13. Wiley, J. J., Pegington, J., and Horwich, J. P.: Traumatic dislocation of the radius at the elbow. J. Bone Joint Surg. 56B:501, 1974. 14. Wright, P. R.: Greenstick fractures of the upper end of the ulna with dislocation of the radial humeral joint or displacement of the superior radial epiphysis. J. Bone Joint Surg. 45B:727, 1963. 15. Yates, C., and Sullivan, J. A.: Arthrographic diagnosis of elbow injuries in children. Pediatr. Orthop. 7:54, 1987. 16. Zivkovic, T.: Traumatic dislocation of the radial head in a 5-year-old boy. J. Trauma 18:289, 1978. DEVELOPMENTAL DISLOCATION OF THE RADIAL HEAD 17. Cummings, R. J., Jones, E. T., Reed, F. E., and Mazur, J. M.: Infantile dislocation of the elbow complicating obstetric palsy. J. Pediatr. Orthop. 16:589, 1996. 18. De Boeck, H.: Treatment of chronic isolated radial head dislocation in children. Clin. Orthop. Rel. Res. 380:215, 2000. 19. Hirayama, T., Takemitsu, Y., Yagihara, K., and Mikita, A.: Operation for chronic dislocation of the radial head in children. Reduction by osteotomy of the ulna. J. Bone Joint Surg. 69:639, 1987. 20. Lloyd-Roberts, G. C., and Bucknill, T. M.: Anterior dislocation of the radial head in children-etiology. Natural history and management. J. Bone Joint Surg. 59B:402, 1977. 21. Pletcher, D., Hofer, M. M., and Koffman, D. M.: Nontraumatic dislocation of the radial head in cerebral palsy. J. Bone Joint Surg. 58A:104, 1976. 22. Peeters, R. L. M.: Radiological manifestations of the Cornelia de Lange syndrome. Pediatr. Radiol. 3:41, 1975.

Chapter 20 Dislocations of the Child’s Elbow

23. Salama, R., Weintroub, S., and Weissman, S. L.: Recurrent dislocation of the radial head. Clin. Orthop. Rel. Res. 125:156, 1977. 24. Silberstein, M. J., Brodeur, A. E., and Graviss, E. R.: Some vagaries of the radial head and neck. J. Bone Joint Surg. 64A:1153, 1982. 25. Southmayd, W., and Parks, J. C.: Isolated dislocation of the radial head without fracture of the ulna. Clin. Orthop. Rel. Res. 97:94, 1973. 26. Subbarao, J. V., and Kumar, V. N.: Spontaneous dislocation of the radial head in cerebral palsy. Orthop. Rev. 16:457, 1987. CONGENITAL DISLOCATION OF THE RADIAL HEAD 27. Almquist, E. E., Gordon, L. H., and Blue, A. I.: Congenital dislocation of the head of the radius. J. Bone Joint Surg. 51A:1118, 1969. 28. Bell, S. N., Morrey, B. F., and Bianco, A. J. Jr.: Chronic posterior subluxation and dislocation of the radial head. J. Bone Joint Surg. 73:392, 1991. 29. Carevias, D. E.: Some observations on congenital dislocation of the head of the radius. J. Bone Joint Surg. 39B:86, 1957. 30. Cockshott, W. P., and Omololu, A.: Familial posterior dislocation of both radial heads. J. Bone Joint Surg. 40B:484, 1958. 31. Gattey, P. H., and Wedge, J. H.: Unilateral posterior dislocation of the radial head in identical twins. J. Pediatr. Orthop. 6:220, 1989. 32. Gunn, D. R., and Pilley, V. K.: Congenital dislocation of the head of the radius. Clin. Orthop. Rel. Res. 84:108, 1964. 33. Kelikian, H. (ed): Dislocation of the radial head. In Congenital Deformities of the Hand and Forearm. Philadelphia, W. B. Saunders Co., 1974, p. 902. 34. Kelly, D. W.: Congenital dislocation of the radial head: spectrum and natural history. J. Pediatr. Orthop. 1:295, 1981. 35. Mardam-Bey, T., and Ger, E.: Congenital radial head dislocation. J. Hand Surg. 4:316, 1979. 36. Mital, M. A.: Congenital radial ulnar synostosis and congenital dislocation of the radial head. Orthop. Clin. North Am. 7:375, 1976. 37. Miura, T.: Congenital dislocation of the radial head. J. Hand Surg. 15B:477, 1990. 38. Mizuno, K., Usui, Y., Kohyama, K., and Hirohata, K.: Familial congenital unilateral anterior dislocation of the radial head: differentiation from traumatic dislocation by means of arthrography. J. Bone Joint Surg. 73A:1086, 1991. MONTEGGIA FRACTURE-DISLOCATION OF THE ELBOW IN CHILDREN 39. Bado, J. L.: The Monteggia lesion. Clin. Orthop. Rel. Res. 50:71, 1967. 40. Boyd, H. B., and Boals, J. C.: The Monteggia lesion: a review of 159 cases. Clin Orthop 66:94, 1969. 41. Bruce, H. E., Harvey, J. P. W., and Wilson, J. C., Jr.: Monteggia fractures. J. Bone Joint Surg. 56A:1563, 1974. 42. Bell-Tawse, A. J. F.: The treatment of malunited anterior Monteggia fractures in children. J. Bone Joint Surg. 47B:718, 1965.

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43. Cappellino, A., Wolfe, S. W., and Marsh, J. S.: Use of a modified Bell Tawse procedure for chronic acquired dislocation of the radial head. J. Pediatr. Orthop. 18:410, 1998. 44. Dormans, J. P., and Rang., M.: The problem of Monteggia fracture dislocations in children. Orthop. Clin. North Am. 21:251, 1990. 45. Evans, E. M.: Pronation injuries of the forearm with special reference to the anterior Monteggia fracture. J. Bone Joint Surg. 31B:578, 1949. 46. Fahmy, N. R. M.: Unusual Monteggia lesions in children. Injury 12:399, 1981. 47. Freedman, L., Luk, K., and Leong, J. C.: Radial head reduction after a missed Monteggia fracture: brief report. J. Bone Joint Surg. 70:846, 1988. 48. Hume, A. C.: Anterior dislocation of the head of the radius associated with undisplaced fracture of the olecranon in children. J. Bone Joint Surg. 39B:508, 1957. 49. Hurst, L. C., and Dubrow, E. N.: Surgical treatment of symptomatic chronic radial head dislocation: a neglected Monteggia fracture. J. Pediatr. Orthop. 3:227, 1983. 50. Kalamchi, A.: Monteggia fracture dislocation in children. Late treatment in two cases. J. Bone Joint Surg. 68:615, 1986. 51. Letts, M., Locht, R., and Weins, J.: Monteggia fracture dislocations in children. J. Bone Joint Surg. 67:724, 1985. 52. Mullick, S.: The lateral Monteggia fracture. J. Bone Joint Surg. 59A:543, 1977. 53. Olney, B. W., and Menelaus, M. B.: Monteggia and equivalent lesions in childhood. J. Pediatr. Orthop. 9:219, 1989. 54. Ovesen, O., Brok, K. E., Arreskov, J., and Bellstrom, T.: Monteggia lesions in children and adults: an analysis of etiology and long-term results of treatment. Orthopedics 13:529, 1990. 55. Papavasiliou, V. A., and Nenopoulos, S. P.: Monteggiatype elbow fractures in children. Clin. Orthop. Rel. Res. 233:230, 1988. 56. Peterson, H. A., and Seel, M. J.: Management of posttraumatic chronic radial head dislocation in children. Presented at the 1998 Annual Meeting of the Pediatric Orthopaedic Society of North America, Cleveland, Ohio, May 7, 1998. 57. Ravessoud, F. A.: Lateral condylar fracture and ipsilateral ulnar shaft fracture: Monteggia equivalent lesions. J. Pediatr. Orthop. 5:364, 1985. 58. Ring, D., and Waters, P. M.: Operative fixation of Monteggia fractures in children. J. Bone Joint Surg. 78B:734, 1996. 59. Spinner, M., Freundlich, B. D., and Teicher, J.: Posterior interosseous nerve palsy as a complication of Monteggia fractures in children. Clin. Orthop. Rel. Res. 58:141, 1968. 60. Stein, F., Grabias, S. L., and Deffer, P. A.: Nerve injuries complicating Monteggia lesions. J. Bone Joint Surg. 53A:1432, 1971. 61. Theodorou, S. D.: Dislocation of the head of the radius associated with fractures of the upper end of the ulna in children. J. Bone Joint Surg. 51B:70, 1969.

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62. Tompikins, D. G.: The anterior Monteggia fracture. Observations on etiology and treatment. J. Bone Joint Surg. 53A:1009, 1971. 63. Wang, M. N., and Chang, W. N.: Chronic posttraumatic anterior dislocation of the radial head in children: thirteen cases treated by open reduction, ulnar osteotomy, and annular ligament reconstruction through a Boyd incision. J. Orthop. Trauma 20:1, 2006. 64. Wiley, J. J., and Galey, J. P.: Monteggia injuries in children. J. Bone Joint Surg. 69B:728, 1985. 65. Wright, P. R.: Greenstick fracture of the upper end of the ulna with dislocation of the radiohumeral joint or displacement of the superior radial epiphysis. J. Bone Joint Surg. 45B:727, 1963. ACUTE DISLOCATION OF THE ELBOW IN CHILDREN 66. Aitken, A. P., and Childress, H. M.: Inter-articular displacement of the internal epicondyle following dislocation. J. Bone Joint Surg. 20:161, 1938. 67. Aufranc, O. E., Jones, W. M., Turner, R. H., and Thomas, W. H.: Dislocation of the elbow with fracture of the radial head and distal radius. J. A. M. A. 202:131, 1967. 68. Beghin, J. L., Bucholz, R. W., and Wenger, D. R.: Intracondylar fractures of the humerus in young children. J. Bone Joint Surg. 64A:1083, 1982. 69. Bilett, D. M.: Unreduced posterior dislocation of the elbow. J. Trauma 19:186, 1979. 70. Blatz, D. J.: Anterior dislocation of the elbow in a case of Ehlers-Danlos syndrome. Orthop. Rev. 10:129, 1981. 71. Bulut, G., Erken, H. Y., Tan, E., Ofluolu, O., and Yildiz, M.: Treatment of medial epicondyle fractures accompanying elbow dislocations in children. Acta Orthop. Traumatol. Turc. 39:334, 2005. 72. Caravias, D. E.: Forward dislocation of the elbow without fracture of the olecranon. J. Bone Joint Surg. 39B:334, 1957. 73. D’Ambrosia, R., and Zink, W.: Fractures of the elbow in children. Pediatr. Ann. 11:541, 1982. 74. Davidson, R. S., Markowitz, R. I., Dormans, J., and Drummond, D. S.: Ultrasonographic evaluation of the elbow in infants and young children after suspected trauma. J. Bone Joint Surg. 76A:1804, 1994. 75. De Lee, J. C.: Transverse divergent dislocation of the elbow in a child. J. Bone Joint Surg. 63A:322, 1981. 76. De Lee, J. C., Wilkens, K. E., Rogers, K. F., and Rockwood, C. A.: Fracture separation of the distal humeral epiphysis. J. Bone Joint Surg. 62A:46, 1980. 77. Eppright, R. H., and Wilkins, K. E.: Fractures and dislocations of the elbow. In Rockwood, C. A. Jr., and Green, D. P. (eds.): Fractures, Vol. 1. Philadelphia, J. B. Lippincott Co., 1975, p. 487. 78. Fowles, J. V., Slimane, N., and Kassab, M. T.: Elbow dislocation with avulsion of the medial humeral epicondyle. J. Bone Joint Surg. 72:102, 1990. 79. Grantham, S. A., and Tietjen, R.: Transcondylar fracturedislocation of the elbow. J. Bone Joint Surg. 58A:1030, 1976. 80. Heilbronner, D. M., Manili, A., and Little, R. E.: Elbow dislocation during overhead skeletal traction therapy. Clin. Orthop. Rel. Res. 147:185, 1981.

81. Holbrook, J. L., and Green, N. E.: Divergent pediatric elbow dislocation. A case report. Clin. Orthop. Rel. Res. 234:72, 1988. 82. Kaplan, S. S., and Reckling, R. W.: Fracture separation of the lower humeral epiphysis with medial displacement. J. Bone Joint Surg. 53A:1105, 1971. 83. Lee, H. H., Shen, H. C., Chang, J. H., Lee, C. H., and Wu, S. S.: Operative treatment of displaced medial epicondyle fractures in children and adolescents. J. Shoulder Elbow Surg. 14:178, 2005. 84. Lejman, T., Kowalczyk, B., and Felu, J.: Does coexistent fractures impair the results of treatment of elbow dislocations in children? Chir. Narzadow Ruchu Ortop Pol. 71:137, 2006. 85. Linscheld, R. L., and Wheeler, D. K.: Elbow dislocations. J. A. M. A. 194:1171, 1965. 86. McAuliffe, T. B., and Williams, D.: Transverse divergent dislocation of the elbow. Injury 19:279, 1988. 87. Meyn, M. A., Jr., and Quibley, T. B.: Reduction of posterior dislocation of the elbow by traction on the dangling arm. Clin. Orthop. Rel. Res. 103:106, 1974. 88. Oury, J. H., Roe, R. D., and Laning, R. C.: A case of bilateral anterior dislocations of the elbow. J. Bone Joint Surg. 12:170, 1972. 89. Patrick, J.: Fracture of the medial epicondyle with displacement into the elbow joint. J. Bone Joint Surg. 28:143, 1946. 90. Protzman, R. R.: Dislocation of the elbow joint. J. Bone Joint Surg. 60A:539, 1978. 91. Rang, M.: Children’s Fractures. Philadelphia, J. B. Lippincott Co., 1983. 92. Rasool, M. N.: Dislocations of the elbow in children. J. Bone Joint Surg. 86B:1050, 2004. 93. Schwab, G. H., Bennett, J. B., Woods, G. W., and Tollos, H. S.: Biomechanics of elbow instability—the medial collateral ligament. Clin. Orthop. Rel. Res. 146:42, 1980. 94. Smith, F. M.: Children’s elbow injuries: fractures and dislocations. Clin. Orthop. Rel. Res. 50:7, 1967. 95. Smith, F. M.: Displacement of the medial epicondyle of the humerus into the elbow joint. Ann. Surg. 124:410, 1946. 96. Sovio, O. M., and Tredwell, S. J.: Divergent dislocation of the elbow in a child. J. Pediatr. Orthop. 6:96, 1986. 97. Tachdjian, M. O.: Pediatric Orthopaedics, Vol. 2. Philadelphia, W. B. Saunders Co., 1972, p. 1604. COMPLICATIONS OF DISLOCATION OF THE ELBOW IN CHILDREN 98. Boe, S., and Holst-Neilson, F.: Intra-articular entrapment of the median nerve after dislocation of the elbow. J. Hand Surg. 12:356, 1987. 99. Floyd, W. E., 3rd, Gebhardt, M. C., and Emans, J. B.: Intraarticular entrapment of the median nerve after elbow dislocation in children. J. Hand Surg. 12:704, 1987. 100. Grimer, R. J., and Brooks, S.: Brachial artery damage accompanying closed posterior dislocation of the elbow. J. Bone Joint Surg. 67:378, 1985. 101. Green, N. E.: Entrapment of the median nerve following elbow dislocation. J. Pediatr. Orthop. 3:384, 1983. 102. Hallet, J.: Entrapment of the median nerve after dislocation of the elbow. J. Bone Joint Surg. 63B:408, 1981.

Chapter 20 Dislocations of the Child’s Elbow

103. Kerian, R.: Elbow dislocation and its association with vascular disruption. J. Bone Joint Surg. 51:756, 1969. 104. Louis, D. S., Ricciardi, J., and Sprengler, D. M.: Arterial injuries: a complication of posterior elbow dislocation. J. Bone Joint Surg. 56A:1631, 1974. 105. Matev, I.: A radiological sign of entrapment of the median nerve in the elbow joint after posterior dislocation. J. Bone Joint Surg. 58B:353, 1976. 106. Noonan, K. J., and Blair, W. F.: Chronic median-nerve entrapment after posterior fracture-dislocation of the elbow. J. Bone Joint Surg. 77A:1572, 1995. 107. Rubens, M. K., and Aulicino, P. L.: Open elbow dislocation with brachial artery disruption: a case report and review of the literature. Orthopaedics 9:539, 1986. 108. Stiger, R. N., Larrick, R. D., and Meyer, T. F.: Median nerve entrapment following elbow dislocations in children. J. Bone Joint Surg. 51A:381, 1969. 109. Tayob, A. A., and Shively, R. A.: A bilateral elbow dislocation with inter-articular displacement of medial epicondyle. J. Trauma 20:332, 1980. 110. Thompson, H. C., and Garcia, A.: Myositis ossificans after massive elbow injuries. Clin. Orthop. Rel. Res. 50:129, 1967. RECURRENT DISLOCATION OF THE ELBOW IN CHILDREN 111. Beighton, P., and Horan, F.: Orthopaedic aspects of the Ehlers-Danlos syndrome. J. Bone Joint Surg. 51B:444, 1969. 112. Hall, R. M.: Recurrent posterior dislocation of the elbow joint in a boy. J. Bone Joint Surg. 35B:56, 1953. 113. Hassmann, G. C., Brunn, F., and Neer, C. S.: Recurrent dislocation of the elbow. J. Bone Joint Surg. 57A:1080, 1975. 114. Hening, J. A., and Sullivan, J. A.: Recurrent dislocation of the elbow. J. Pediatr. Orthop. 9:483, 1989. 115. Jacobs, R. L.: Recurrent dislocation of the elbow: a case report and review of the literature. Clin. Orthop. Rel. Res. 74:151, 1971.

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116. Mantle, J.: Recurrent posterior dislocation of the elbow. J. Bone Joint Surg. 48B:590, 1966. 117. Morrey, B. F.: Complex instability of the elbow. J. Bone Joint Surg. 79A:460, 1997. 118. O’Driscoll, S. W., Bell, D. F., and Morrey, B. F.: Posterolateral rotatory instability of the elbow. J. Bone Joint Surg. 73A:440, 1991. 119. Osborne, G., and Cotterill, P.: Recurrent dislocation of the elbow. J. Bone Joint Surg. 48B:340, 1966. 120. Rames, R. D., and Strecker, W. B.: Recurrent elbow dislocations in a patient with Ehlers-Danlos syndrome. Orthopaedics 14:707, 1991. 121. Trias, A., and Comeau, Y.: Recurrent dislocation of the elbow in children. Clin. Orthop. Rel. Res. 100:74, 1974. PULLED ELBOW 122. Amir, D., Frank, J., and Pogrund, H.: Pulled elbow and hypermobility of joints. Clin. Orthop. Rel. Res. 257:94, 1990. 123. Boyette, D. P., Ahoski, H. C., and London, A. H., Jr.: Subluxation of the head of the radius-”nursemaid’s elbow.” J. Pediatr. 32:278, 1948. 124. Choung, W., and Heinrich, S. D.: Acute annular ligament interposition into the radiocapitellar joint in children (nurse maid’s elbow). J. Pediatr. Orthop. 15:454, 1995. 125. Hart, G. M.: Subluxation of the head of the radius in young children. J.A.M.A. 169:1734, 1969. 126. Magill, H. K., and Aitken, A. P.: Pulled elbow. Surg. Gynecol. Obstet. 98:753, 1954. 127. Mehta, L.: Subluxation of radial head in children with reference to radial head and neck diameters. J. Ind. Med. Assoc. 166:220, 1972. 128. Nussbaum, A. J.: The off-profile proximal radial epiphysis: another potential pitfall in the x-ray diagnosis of elbow trauma. J. Trauma. 23:40, 1983. 129. Salter, R. B., and Zaltz, C.: Anatomic investigations of the mechanism of injury and pathologic anatomy of “pulled elbow” in young children. Clin. Orthop. Rel. Res. 77:141, 1971.

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CHAPTER

21

Post-Traumatic Elbow Stiffness in Children Anthony A. Stans and Bernard F. Morrey

ETIOLOGY Elbow stiffness can be categorized as either extraarticular or intra-articular in origin. Heterotopic ossification and soft tissue contracture are two common causes of extrinsic contracture. Early aggressive passive rangeof-motion (ROM) exercises or repeated forceful manipulation during fracture reduction have been associated with heterotopic ossification and elbow stiffness.25,27 Delayed open reduction and internal fixation have also been shown to increase the risk of developing heterotopic ossification.14 Intra-articular T-condylar fractures are rare in children, but when they occur, they frequently are associated with elbow stiffness.9,23 Soft tissue contracture frequently occurs following immobilization or surgical treatment.29 Fracture malunion, callus formation, and degenerative changes are common intra-articular causes of elbow stiffness.30 Anatomic reduction of displaced intraarticular elbow fractures is important to prevent posttraumatic arthritis as well as to maintain the precise anatomic relationships among the three bones that make up the elbow and is required for normal elbow motion.21 If malunion does occur, resulting in articular incongruity or bone impingement, secondary degenerative changes often follow causing intrinsic elbow stiffness (Fig. 21-1).

INCIDENCE Although it is not common, elbow stiffness may occur following almost any form of elbow trauma. Henrikson6 reported stiffness in 3% to 6% of patients treated for supracondylar humerus fractures. Loss of motion following supracondylar humerus fractures may be due to soft tissue contracture or heterotopic ossification. Wedge and Roberson29 reported some loss of elbow motion following radial neck fractures in 33% of patients undergoing open reduction, and in 100% of patients when internal fixation was used. Aside from fractures, patients frequently experience loss of extension following elbow dislocation.11

PRESENTATION Persistent stiffness is the universal presenting chief complaint, but sometimes, particularly in children, it is difficult to know when early stiffness following treatment is appropriate, when the stiffness is a temporary phase of the healing response, and when the stiffness is inappropriate and likely to result in permanent limitation in ROM. After initial treatment of the injury, patients who have not made significant progress toward restoration of normal motion by 2 to 3 months following their injury are at risk for developing permanent elbow stiffness. This is a reasonable period of time to expect stiffness following initial treatment to be significantly improved. Loss of motion accompanied by pain is an infrequent presenting complaint in young patients and was present in only 3 of 28 patients in a series from the Mayo Clinic.26 Symptoms such as catching or locking may be present and suggest the presence of loose bodies within the elbow.

EVALUATION HISTORY A detailed history of the injury and subsequent treatment is typically all that is necessary to determine whether the etiology for the stiffness is extrinsic or intrinsic. Important information to gather includes the mechanism and time of the initial injury, the precise nature of the nonoperative or operative treatment, and the length of the period of immobilization. Knowledge of the nature and duration of any physical therapy is helpful. Information regarding any complication such as a wound healing problem or infection is also useful. Factors commonly seen in the child that strongly suggest an extrinsic etiology include extra-articular fracture, especially supracondylar involvement, simple dislocation without associated fracture, and immobilization lasting longer than 4 weeks. Crush injuries and highenergy injuries with local soft tissue damage also predispose the patients to developing extrinsic contracture. Patients with an associated head injury are at risk for developing an extrinsic contracture due to heterotopic ossification.19 Post-traumatic intrinsic stiffness is most common following an intra-articular fracture. Because these more commonly require open reduction, surgical treatment may contribute to intrinsic etiology, especially if associated with malunion, excess callus formation, or retained hardware. Detailed questioning about the length of time elapsed since the injury and the specific treatment received for the elbow stiffness is

Chapter 21 Post-Traumatic Elbow Stiffness in Children

327

125 degrees of flexion. Extension is the most common portion of the arc affected. Limitation of pronation and supination is observed almost exclusively after radial head and neck fractures and suggests involvement of the radiocapitellar joint or proximal radioulnar synostosis if no rotational motion is present.

Stability Varus or valgus instability is classified by the method of Morrey.20 The elbow is stable if there is no varus or valgus laxity. Mild instability exists if varus or valgus laxity is present but is less than 5 degrees in either direction. Elbows were considered moderately unstable if varus or valgus laxity was considered to be 5 to 10 degrees and associated with mild symptoms. Severely unstable elbows had greater than 10 degrees varus and valgus laxity and caused limitations in daily activities. Varus and valgus instability associated with elbow stiffness is uncommon in children unless bone has been resected.

IMAGING STUDIES Plain Film Radiographs Anteroposterior and lateral radiographs are taken for all patients and provide helpful information regarding fracture union, fracture reduction, elbow alignment, loose bodies, and bone stock.

FIGURE 21-1

A, A 16-year-and-10-month-old boy sustained an injury to his right elbow while playing football, did not seek medical attention, and presented 2 years later with pain, locking, and elbow range of motion from −40 degrees extension to 130 degrees flexion. B, Six months following excision of ectopic bone, excision of loose bodies, anterior capsulotomy, radial head excision, and continuous passive motion with elbow range of motion from −30 degrees extension to 130 degrees flexion.

helpful in determining improvement.

the

likelihood

of

future

EXAMINATION Motion Accurate measurement of elbow range of motion (ROM) with a goniometer is essential. The functional arc of elbow motion is from 30 to 130 degrees.21 Patients with elbow ROM greater than this arc rarely suffer any functional limitation, but it is reasonable to attempt to restore normal ROM through a trial of nonoperative treatment. We have found that the use of splints is helpful and better tolerated than physical therapy (see Chapter 11). Very seldom is surgical treatment indicated for patients with less than 0 degrees of extension loss or greater than

Computed Tomography With the development of high-speed thin slice scanners, in conjunction with software allowing high-resolution two- and three-dimensional reconstruction images, computed tomography (CT) has recently replaced standard tomography as the best means of imaging elbow osseous anatomy. Reconstruction images in the coronal and sagittal planes are the most helpful views in assessing the etiology of elbow stiffness. Lateral reconstruction images are especially helpful in elbows of patients sustaining intra-articular fractures to assess joint congruity and coronal (A-P) plane reconstruction images are most useful when assessing distal humeral anatomy. CT also provides accurate imaging of loose bodies and other osseous pathology impeding elbow ROM, which greatly facilitates preoperative planning and helps ensure that all pathologic conditions contributing to elbow stiffness are identified and addressed at surgery.

Magnetic Resonance Imaging Recent literature has recommended magnetic resonance imaging (MRI) of the stiff elbow.3 However, MRI does not image osseous anatomy as well as other radiographic techniques. For specific indications, MRI can provide helpful information. Evaluation for possible avascular necrosis, physeal injury, and soft tissue lesions

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is often facilitated by MRI. In general, as with CT, transverse images are less helpful in assessing elbow contracture.

TREATMENT: INDICATIONS AND CONTRAINDICATIONS NONOPERATIVE TREATMENT The amount of time transpiring between the injury and the presence of an established contracture affects treatment. Early and aggressive passive ROM exercises have been demonstrated to cause heterotopic ossification in pediatric patients.25 During the first 1 to 3 months following injury; therefore, active ROM is used primarily. We have found swimming to be a very beneficial activity for the treatment of pediatric elbow stiffness. Although the exact mechanism is not clear, it is easy to imagine how swimming or playing in the water is relaxing, soothing, nonthreatening, and safe for children and adolescents. Therefore, we strongly encourage patients to swim regularly as soon as possible following injury or treatment.

Physical Therapy If decreased elbow ROM is present later than 2 to 3 months following injury, passive ROM exercises and stretching may be employed. Passive ROM and stretching should be limited by elbow swelling, pain, and inflammation. Any significant inflammation about the elbow caused by aggressive therapy may worsen elbow stiffness. The use of ice and a scheduled nonsteroidal anti-inflammatory drug (NSAID) often reduces inflammation and improves patient comfort, allowing greater progress to be made with therapy. Ideally, a physical therapist with an interest and competency in upper extremity rehabilitation instructs the patient on a home program of active and gentle passive stretching exercises that the patient performs daily and that are used in combination with ice and NSAIDs. In fact, because the likelihood of the therapist’s being knowledgeable is limited, we prefer splinting to formal physical therapy.

Splinting Previous authors have described the use of static and dynamic splinting to improve elbow ROM. Green and McCoy5 reported the use of a turnbuckle splint for elbow contracture, whereas others have advocated dynamic splinting.7 Our current practice is to use a static splint primarily at night, with an adjustable hinge that can be fixed in any degree of flexion (see Chapter 11). Each night before retiring, the patient applies the brace to the affected elbow. Preferably this is immediately following a session of stretching. Patients with a primary

limitation in extension place the elbow and splint in maximal extension to the point of tolerance and fix the hinge in this position. Conversely, patients with a primary limitation in flexion fix the splint in maximal flexion, again limited by pain. Patients with significant limitation in both planes alternate nights in flexion and extension. This nonoperative regimen of active and passive ROM exercises, NSAIDs, and splinting should be tried for a minimum of 1 and up to 3 months before its effectiveness can be determined.

SURGICAL TREATMENT Patients whose injuries are more than 6 months old and who have failed an adequate trial of nonoperative treatment as described earlier and who experience significant functional limitation due to elbow stiffness may be considered for operative treatment. Successful surgical treatment addresses all extrinsic and intrinsic pathologic elements contributing to stiffness.22 In the pediatric patient, release of the extrinsic soft tissue contracture is typically performed in a manner similar to the technique described by Husband and Hastings8 or Mansat and Morrey.16 Anterior capsulectomy is performed through a lateral Kocher incision for flexion contracture. If the medial capsule cannot be adequately released through the lateral incision, a medial incision is made through which the anterior capsular release is completed.12 Occasionally, the lateral collateral and medial collateral ligaments must also be released to restore adequate motion. Posterior capsulectomy is performed through the same lateral incision if extension contracture is present, hence the term column procedure.16 Thorough inspection of the joint is also performed, and intraarticular pathology causing limitation of elbow motion is treated. The olecranon tip should be excised if it is impinging on the posterior humerus in extension, and the coronoid tip should be excised if it is impinging within the coronoid fossa in flexion (Fig. 21-2). Lysis of adhesions is performed if necessary and any additional pathologic condition, such as loose bodies, addressed. If marked degenerative changes are present at the radiocapitellar joint, causing restricted ROM, radial head excision may be considered in skeletally mature patients (Fig. 21-3). Occasionally, excessive callus formation or malunion results in a bone block to motion, which may be removed deftly using burr or rongeur. We rarely release muscle/tendon units, because these will stretch out after surgery. An important lesson learned is that patients undergoing posterior release for limited elbow flexion frequently develop ulnar neuritis postoperatively. To prevent ulnar neuritis, we are increasingly proactive and in many patients performing in situ decompression of the ulnar nerve within the cubital tunnel, or subcutaneous

Chapter 21 Post-Traumatic Elbow Stiffness in Children

329

FIGURE 21-2

A, A 21-year-old boy sustained a hyperextension injury to his right elbow 6 months previously and presented with elbow range of motion from ±55 degrees extension to 140 degrees flexion. B, Tomographs confirm the presence of a previous olecranon fracture. C, One year following excision of the olecranon tip, anterior capsulotomy, and continuous passive motion, radiographs demonstrate additional ectopic bone formation about the elbow. Range of motion measured −20 degrees extension and 140 degrees flexion.

anterior ulnar nerve transposition at the time of contracture release. This is performed through the medial incision used to complete elbow contracture release. Patients with extensive intra-articular pathology limiting motion, but who have at least 50% of the articular cartilage intact, may benefit from distraction arthroplasty. A recent publication by Mader reported significant elbow motion improvement in 14 pediatric and adolescent patients treated with mechanical distraction.1,15 Patients with intrinsic contracture and less than 50% of the articular cartilage remaining may be considered for fascial interposition arthroplasty.20 It is less common to require these modalities in the pediatric population. Following closure and application of a soft dressing, the patient is allowed to awaken from anesthesia enough to allow neurovascular assessment. If the patient is neurovascularly intact, an indwelling brachial plexus catheter is inserted and continuous passive motion (CPM) is begun immediately. ROM in the CPM machine is rapidly increased to the amount of motion obtainable intraoperatively (see Chapter 10). The brachial plexus

catheter and CPM are continued on an inpatient basis until satisfactory motion is achieved and the patient is able to tolerate continued use of CPM without the brachial plexus catheter. After a total of approximately 3 to 4 days in the hospital, the patient is discharged home with a portable CPM machine to be used for approximately 6 weeks. When not using CPM, the patient typically uses a static adjustable splint. This regimen requires some compliance not readily attainable in the very young patient; as noted earlier, we attempt to defer surgery in those with open physes if possible. If surgery is performed in the younger child, the above-described regimen is modified according to what is attainable by that particular patient.

RESULTS There is a paucity of literature available on the results of treatment for the stiff elbow in pediatric patients. No published results can be found describing nonoperative results in pediatric patients, and only four papers could

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FIGURE 21-3

A, Elbow dislocation with an associated radial head fracture was treated nonoperatively in this 19-year-old patient. B, Tomographs taken 2 months following the injury confirmed persistent displacement and radial head fracture nonunion. Six months after the injury, elbow range of motion measured −35 degrees extension to 115 degrees flexion, and the patient underwent excision of the radial head fragment, anterior capsulectomy, and posterior capsulotomy. C, Eighteen months following his surgery, small remnants of ectopic bone are present about the elbow, and elbow range of motion measures −10 degrees extension to 145 degrees flexion.

be identified describing operative results for the treatment of elbow stiffness in pediatric patients.2,15,18,26 Mih and Wolf18 reported a series of nine pediatric patients treated surgically for elbow stiffness. Six of the nine patients had post-traumatic stiffness, and the remaining three patients had stiffness secondary to juvenile rheumatoid arthritis, hemophilia, or avascular necrosis of the capitellum. Preoperatively, patients had a mean total arc of motion of 55 degrees, which improved to 108 degrees at a mean duration of follow-up of 17 months. We have reviewed our experience with patients age 21 or younger who underwent surgical treatment for elbow stiffness at the Mayo Clinic since 1979.26 Thirtynine patients were identified, 28 of whom developed stiffness following trauma. Excluding nontraumatic eti-

ology, eight patients had a complex fracture with associated elbow dislocation, seven sustained an isolated intra-articular elbow fracture, five patients an isolated elbow dislocation, four patients an extra-articular distal humerus fracture, and four patients a soft tissue injury or contusion without an elbow dislocation or fracture. All patients had failed a trial of nonoperative treatment and had functional limitation because of restricted ROM. Surgical procedures performed are listed in Table 21-1; as noted, virtually all underwent anterior release. Mean preoperative and postoperative ROMs are displayed in Table 21-2. The mean arc of motion improved from 66 degrees preoperatively to only 94 degrees after surgery. These results suggest that, at least in our

Chapter 21 Post-Traumatic Elbow Stiffness in Children

experience, pediatric patients tend to regain less motion than adult patients treated for post-traumatic elbow stiffness (Fig. 21-4).4,8,20,28 Also of note is that, unlike in the adult population, three patients regained no motion or even lost motion after surgery.

ARTHROSCOPIC RELEASE Arthroscopic elbow contracture release has gained increasing popularity in the treatment of adult patients with elbow stiffness10,13,24 and has been used with increasing frequency in pediatric and adolescent patients Surgical Procedures Performed in 28 Pediatric Patients with Elbow Stiffness

TABLE 21-1 Procedure

Number of Patients

Anterior capsulotomy

26

Posterior capsulotomy

12

Olecranon tip excision

9

Radial head excision

7

Osteophyte/heterotopic bone excision

6

External fixation

5

Fascial arthroplasty

3

Hardware removal

3

Loose body removal

3

Coronoid tip excision

2

Humeral contouring

2

TABLE 21-2

331

at the Mayo Clinic.17 Between 1997 and 2004, 45 pediatric and adolescent patients underwent arthroscopic elbow contracture release at the Mayo Clinic. In Table 21-3, motion arc improvement following arthroscopic release in pediatric patients is compared with improvement following open surgical treatment in pediatric patients and following open surgical treatment in adult patients from the same institution. The results of arthroscopic pediatric elbow contracture release appear to be slightly better than open contracture release for pediatric patients but not as successful as open contracture release in adult patients. It is unclear at this time if the improved motion following arthroscopic surgery is a consequence of arthroscopic technique or the result of more consistent use of CPM, static adjustable splinting or other factors.

COMPLICATIONS The combination of previous surgery, extensive dissection, external fixation, and immediate ROM following surgery places surgical patients at risk for complications. In the Mayo series, there was one deep wound infection requiring surgical débridement, one transient radial nerve palsy, one postoperative hematoma that required surgical evacuation, and three patients with persistent contracture without improvement following surgery. Patients undergoing distraction arthroplasty or fascial interposition arthroplasty are at greater risk for complications than patients treated with surgical release without external fixation.20

Preoperative and Postoperative Elbow Ranges of Motion Extension

Flexion

Total Arc

Pronation

Supination

Preoperative

−51

117

66

63

64

Postoperative

−32

129

94

73

64

120° 101°

129° 117°

92°

97° 49°

66°

52°

54° 0°

A

0°

32° Pediatric

B

28° Adult

FIGURE 21-4

The mean motion in the pediatric patient averaged about 65 degrees before and 95 degrees after surgery (A). This is less than the 60 degree improvement often seen in the adult (B).

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Part IV Conditions Affecting the Child’s Elbow

Comparison Between Open Adult, Open Pediatric, and Arthroscopic Pediatric Elbow Contracture Release

TABLE 21-3

Motion Arc Improvement

Mansat

45

Stans

28

McIntosh

38

AUTHORS’ CURRENT PRACTICE The assessment and surgical techniques for treating contracture in the child is similar to that of the adult. However, because of compliance issues as well as problems with less predictable response to surgery, we make every effort to avoid surgical release until the physes have closed. In children and adolescents at risk of developing elbow stiffness, we immediately initiate a patient and family directed active and active-assisted home stretching program. Encouraging children to swim early and often is frequently very helpful. The use of splints before surgery is particularly helpful to improve the motion arc to the extent that surgery may be able to be avoided, it allows assessment of compliance, and splints can be used after surgery should this become necessary. A home splint therapy program is preferred to formal physical therapy and is most effective when used within 3 to 6 months after the onset of stiffness. Surgical treatment for elbow stiffness in the pediatric patient is to be avoided whenever possible, and the unpredictable nature of the procedure must be carefully explained to the patient and his or her family before surgery is undertaken. When performing surgical contracture release, we currently have a low threshold for ulnar nerve decompression in patients lacking flexion or in patients with any symptoms of ulnar neuritis. Depending on surgeon experience as well as concomitant factors such as retained hardware, we may perform the release open or arthroscopically. Postoperatively, the use of CPM for approximately 6 weeks following surgery and compliance with a static adjustable splinting program remain essential to preserving the motion improvement achieved at surgery.

References 1. Ayoub, K., Gibbons, P., and Bradish, C. F.: Compass elbow hinge: Short-term results in five adolescents. J. Pediatr. Orthop. Part B 13:395, 2004. 2. Bae, D. S., and Waters, P. M.: Surgical treatment of posttraumatic elbow contracture in adolescents. J. Pediatr. Orthop. 21:580, 2001.

3. Fortier, M. V., Forster, B. B., Pinney, S., and Regan, W.: MR assessment of post-traumatic flexion contracture of the elbow. J. Magnet. Res. Imag. 5:473, 1995. 4. Gates, H. S., Sullivan, F. L., and Urbaniak, J. R.: Anterior capsulotomy and continuous passive motion in the treatment of post-traumatic flexion contracture of the elbow. J. Bone Joint Surg. 74A:1229, 1992. 5. Green, D. P., and McCoy, H.: Turnbuckle orthotic correction of elbow-flexion contractures after acute injuries. J. Bone Joint Surg. 61A:1092, 1979. 6. Henrikson, B.: Supracondylar fracture of the humerus in children. Acta Chir. Scand. 369:1, 1966. 7. Hepburn, G. R., and Crivelli, K. J.: Use of elbow Dynasplint for reduction of elbow flexion contracture. J. Sports Ther. 5:269, 1984. 8. Husband, J. B., and Hastings, H.: The later approach for operative release of post-traumatic contracture of the elbow. J. Bone Joint Surg. 72A:1353, 1990. 9. Jarvis, J. G., and D’Astous, J. L.: The pediatric T-supracondylar fracture. J. Pediatr. Orthop. 4:697, 1984. 10. Jones, G. S., and Savoie, F. H.: Arthroscopic capsular release of flexion contractures (arthrofibrosis) of the elbow. Arthroscopy 9:277, 1993. 11. Josefsson, O., Gentz, C., and Johnell, O.: Surgical versus nonsurgical treatment of ligamentous injuries following dislocations of the elbow joint. A prospective randomized study. J. Bone Joint Surg. 69A:605, 1987. 12. Jupiter, J. B., O’Driscoll, S. W., and Cohen, M. S.: The assessment and management of the stiff elbow. Instruc. Course Lect. 52:93, 2003. 13. Kim, S. J., and Shin, S. J.: Arthroscopic treatment for limitation of motion of the elbow. Clin. Orthop. Rel. Res. 375:140, 2000. 14. Lal, H. M., and Bhan, S.: Delayed open reduction for supracondylar fractures of the humerus. Int. Orthop. 15:189, 1991. 15. Mader, K., Koslowsky, T. C., Gausepohl, T., and Pennig, D.: Mechanical distraction for the treatment of posttraumatic stiffness of the elbow in children and adolescents. Surgical Technique. J. Bone Joint Surg. 89A(Part 1, Suppl 2):26, 2007. 16. Mansat, P., and Morrey, B. F.: The column procedure: a limited lateral approach for extrinsic contracture of the elbow. J. Bone Joint Surg. 80A:1603, 1998. 17. McIntosh, A., and O’Driscoll, S. W.: Arthroscopic treatment of elbow stiffness in pediatric and adolescent patients. Presented at the American Shoulder and Elbow Surgeons Specialty Day, AAOS Annual Meeting, San Diego CA, Feb. 17, 2007. 18. Mih, A. D., and Wolf, F. G.: Surgical release of elbow-capsular contracture in pediatric patients. J. Pediatr. Orthop. 14:458, 1994. 19. Mital, M. A., Barber, J. E., and Stinson, J. T.: Ectopic bone formation in children and adolescent with head injuries: its management. J. Pediatr. Orthop. 7:83, 1987. 20. Morrey, B. F.: Post-traumatic contracture of the elbow. J. Bone Joint Surg. 72A:601, 1990. 21. Morrey, B. F., Askew, L. J., An, K. N., and Chao, E. Y.: A biomechanical study of normal functional elbow motion. J. Bone Joint Surg. 63A:872, 1981.

Chapter 21 Post-Traumatic Elbow Stiffness in Children

22. Papandrea, R., Waters, P. M.: Posttraumatic reconstruction of the elbow in the pediatric patient. Clin. Orthop. (370):115126, 2000. 23. Papvasilious, V. A., and Beslikas, T. A.: T-condylar fractures of the distal humeral condyles during childhood: an analysis of six cases. J. Pediatr. Orthop. 6:302, 1986. 24. Phillips, B. B., and Strasburger, S.: Arthroscopic treatment of arthrofibrosis of the elbow joint. Arthroscopy 14:38, 1998. 25. Pirone, A. M., Graham, H. K., and Krajbich, J. I.: Management of displaced extension-type supracondylar fractures of the humerus in children. J. Bone Joint Surg. 70A:641, 1988. 26. Stans, A. A., Maritz, N. G. J., O’Driscoll, S. W., and Morrey, B. F.: Operative treatment of elbow contracture in patients

27.

28.

29.

30.

333

21 years of age or younger. J. Bone Joint Surg. 84A:382, 2002. Thompson, H. G., and Garcia, A.: Myositis ossificans: aftermath of elbow injuries. Clin. Orthop. Rel. Res. 50:129, 1967. Urbaniak, J. R., Hansen, P. E., Beissinger, S. F., and Aitken, M.: Correction of post-traumatic flexion contracture of the elbow by anterior capsulotomy. J. Bone Joint Surg. 67A:1160, 1985. Wedge, J. H., and Roberson, D. E.: Displaced fractures of the neck of the radius. J. Bone Joint Surg. 64B:256, 1982. Zionts, L. E., and Mirzayan, R.: Fracture of the lateral epicondyle of the humerus in a child: A case report. J. Bone Joint Surg. 84A:818, 2002.

SECTION

A

FRACTURES AND DISLOCATIONS

CHAPTER

22

Current Concepts in Fractures of the Distal Humerus Shawn W. O’Driscoll

INTRODUCTION Dramatic changes have occurred in the treatment of elbow fractures in recent years. This is especially true for distal humerus fractures. Although improvements in fracture-specific fixation devices have occurred, the most important advances can be attributed to a principlebased approach to these fractures. Recovery of painless and satisfactory elbow function after a fracture of the distal humerus requires anatomic reconstruction of the articular surface, restitution of the overall geometry of the distal humerus and stable fixation of the fracture fragments to allow early and full rehabilitation.2,4,5,7-9,14 Although these goals are obvious, the orthopedic community would agree that they may be technically difficult to achieve, especially in the presence of substantial osteoporosis or comminution.14 The techniques proposed by the AO/ASIF group had been standard for fixation of distal humerus fractures in the past.8,14 Their recommended technique included fixation of the articular fragments with screws and column stabilization with two plates at a 90-degree angle to one another.3,8,19 Fracture stability is only as secure as the fixation of the distal fragment to the shaft. Using standard AO/ASIF techniques, different authors

have reported unsatisfactory results in 20% to 25% of patients.2,4,5,7-9 Improvements in the treatment of these fractures recently have been predicated on understanding and overcoming the limitations and reasons for failure of previous techniques. When treatment of severe distal humerus fractures fails, it typically is due to either nonunion at the supracondylar level or stiffness resulting from prolonged immobilization that has been used in an attempt to avoid failure of inadequate fixation.14 Either way, the limiting factor is fixation of the distal fragments to the shaft. In an effort to increase the yield of excellent and satisfactory results obtained after fixation of distal humerus fractures and to reproducibly obtain stable fixation in the presence of osteoporosis or comminution, I recommend (and have used for two decades) an alternative philosophy and technique based on principles that maximize fixation in the distal fragments and compression at the supracondylar level.11-13,15,17 The key to the stability achieved with this fixation construct is that it combines the features and stability of an arch while locking the two columns of the distal humerus together. The stability achieved allows routine commencement of an intensive rehabilitation program postoperatively, including full active motion with no external protection. The following discussion expands on the general principles of our current approach to these fractures, the specific technical details, the postoperative program, and the potential complications.

PRINCIPLE-BASED FIXATION PRINCIPLES AND TECHNICAL OBJECTIVES Before discussing the details of surgical techniques, it is imperative that the treating surgeon understand the principles (Box 22-1) and technical objectives (Box 22-2) that, if followed and achieved respectively, will maximize the likelihood of a successful outcome from treatment of these fractures. 337

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Part V Adult Trauma

PRINCIPLE-BASED SURGICAL TECHNIQUE BOX 22-1

Principles of Fracture Fixation Surgery The surgical technique is performed in five steps:

The principles by which the earlier mentioned goals are achieved, and the technical objectives at the time of surgery for achieving them, are 1. Maximize fixation in the distal fragment. 2. All fixation in distal fragments should contribute to stability between the distal fragments and the shaft.

BOX 22-2

Technical Objective Checklist

Concerning screws in the distal fragments (articular segment): 1. Each screw should pass through a plate. 2. Each screw should engage a fragment on the opposite side that is also fixed to a plate. 3. An adequate number of screws should be placed in the distal fragments. 4. Each screw should be as long as possible. 5. Each screw should engage as many articular fragments as possible. 6. The screws should lock together by interdigitation, thereby creating a fixed angle structure and linking the columns together. Concerning the plates used for fixation: 7. Plates should be applied such that compression is achieved at the supracondylar level for both columns. 8. Plates used must be strong enough and stiff enough to resist breaking or bending before union occurs at the supracondylar level.

EXPOSURE The operation is performed with the patient in the supine position. A sterile tourniquet is inflated only for dissection of the ulnar nerve, which is transposed anteriorly. The triceps-anconeus reflecting pedicle (TRAP) approach provides adequate exposure for a surgeon experienced with the technique.10 This technique involves combining the Bryan-Morrey and modified Kocher approaches to reflect the triceps in continuity with the anconeus. However, I believe that an olecranon osteotomy provides even greater exposure and is recommended in the setting of intra-articular comminution. The TRAP approach is indicated if total elbow replacement is necessary.

1. 2. 3. 4. 5.

Articular reduction Plate application and provisional fixation Distal fixation Supracondylar compression Final fixation

Stability and function are restored by achieving eight technical objectives (see Box 22-2) derived from the principles of (1) maximizing fixation in the distal fragments, and (2) ensuring that all fixation in the distal segment contributes to stability at the supracondylar level (see Box 22-1) (Fig. 22-1). All eight of these objectives are achieved with the technique of what we term parallel plating. The medial plate is placed on the medial aspect of the medial column, and the lateral plate is placed laterally, rather than posteriorly, on the lateral column. Although we refer to them as parallel, each plate is actually rotated posteriorly slightly out of the sagittal plane such that the angle between them is often in the range of 150 to 160 degrees. This orientation permits insertion of at least four long screws completely through the distal fragments from one side to the other. These screws interdigitate, thereby creating a fixed-angle structure and greatly increasing stability of the construct. Contact between screws is intended to enhance the locking together of the two columns. The plates must be contoured to fit the geometry of the distal humerus if precontoured plates are not available, but the latter facilitate anatomic reconstruction. Interfragmentary compression is obtained between articular fragments as well as at the metaphyseal level through the use of large bone clamps that provide compression during the insertion of the screws attaching the articular segment to the shaft. In the distal fragments, fully threaded screws inserted in this manner provide maximum thread purchase in the distal fragments. Additional compression at the metaphyseal level results from slight undercontouring of the plates and the use of dynamic compression holes in the plates. The specific steps of the surgical technique are detailed below.

STEP 1. ARTICULAR SURFACE REDUCTION Once the fracture is exposed, the first step is reassembly of the articular surface. The proximal ulna and radial head can be used as a template for the reconstruction of the distal humerus. The articular fragments are provisionally fixed with smooth Kirschner wires

Chapter 22 Current Concepts in Fractures of the Distal Humerus

339

FIGURE 22-1

The technical objectives described in this paper are illustrated. The screws in the distal fragments interlock, providing additional stability to the construct by “closing the arch.” Interlocking is best achieved by contact between the screws. The combination of multiple screws crisscrossing in close proximity with bone between them gives a “rebar” (reinforced concrete) type structure.

Fragment rotation

FIGURE 22-2

Step 1

(K wires) (Fig. 22-2). In cases with extensive comminution, fine threaded wires (1 to 1.5 mm) are used, then cut off and left in as definitive adjunctive fixation. K wires permit assembly of the joint surface fragments in a manner that is analogous to the use of dowels

Step 1. Articular reduction. The articular fragments, which tend to be rotated toward each other in the axial plane, are reduced anatomically and provisionally held with 0.035 inches or 0.045 inches smooth Kirchner wires. It is essential that the wires be placed close to the subchondral level, to avoid interference with later screw placement, and away from where the plates will be placed on the lateral and medial columns. One or two strategically placed pins can be used to provisionally hold the distal fragments aligned with the shaft.

in furniture making. It is necessary that these wires be placed close to the subchondral level so as not to interfere with the passage of screws from the plates into the distal fragments; specifically, no screws are placed in the distal fragments until the plates are

340

Part V Adult Trauma

applied. The articular fragments are fixed in the following order: 1.a. Anterior trochlea and capitellum 1.b. Medial trochlea 1.c. Posterior fragments The articular surface of the distal humerus should be reconstructed anatomically unless bone is missing. In the event of absent bone, two important principles should be taken into consideration. First, the anterior aspect of the distal humerus is the critical region that needs to be restored in order to have a functional joint; reconstruction of the posterior articular surface of the distal humerus is less critical. Second, stability of the articulation requires the presence of the medial trochlea in combination with either the lateral half of the trochlea or the capitellum; thus, the medial trochlea is essential to obtain a stable and well-aligned joint.

STEP 2. PLATE APPLICATION AND PROVISIONAL FIXATION We routinely use precontoured medial and lateral plates from the Mayo Congruent Elbow Plate System (Acumed, Hillsboro, OR) (Fig. 22-3). The medial plate can be extended

to the articular margin in very distal or comminuted fractures and is contoured to the shape of the medial epicondyle. The ulnar nerve must be transposed if this extended plate is used. The distal end placed more posteriorly to prevent impinging on, or cutting into, the common extensor tendon and lateral collateral ligament complex. Both plates should be slightly undercontoured to provide additional compression at the metaphyseal region when applied. The length of the plates is selected so that at least three screws are placed both medially and laterally proximal to the metaphyseal component of the fracture. These plates are designed so that in any combination they will end at different levels to avoid the creation of a stress riser proximally. The plates are then provisionally applied according to the following steps: 1. Two smooth Steinmann pins (2.0 to 2.5 mm) are introduced at the medial and lateral epicondyles through holes in the plates while they are held accurately against the bone; the most commonly used holes are the second one laterally and the third medially. These pins are left in place until after step 4 (see later). The pins create pilot holes for later replacement with screws, are easy to drill around, and do not interfere as much with placement of the two distal screws, as would be the case if they were replaced by screws earlier. 2. The appropriate reduction of the distal fragments to the humeral shaft at the supracondylar level is confirmed. 3. One cortical screw is loosely introduced into a slotted hole to hold each plate in place. Use of slotted holes for these screws facilitate later adjustments in plate positioning.

STEP 3. DISTAL FIXATION

Step 2 FIGURE 22-3

Step 2. Plate application and provisional fixation. Medial and lateral precontoured plates are placed and held apposed to the distal humerus, while one smooth 2 or 2.5 mm Steinmann pin is inserted through hole #2 (numbered from distal to proximal) of each plate, through the epicondyles, and across the distal fragments, to maintain provisional fixation of the plates to the distal fragments. A screw is placed in the slotted hole (#5) of each plate, but not fully tightened, leaving some freedom for the plate to move proximally later during compression. Because the undersurface of each plate is tubular in the metaphyseal and diaphyseal regions, the screw in the slotted hole only needs to be tightened slightly to provide excellent provisional fixation of the entire distal humerus.

Once the plates are provisionally applied, medial and lateral screws are introduced distally to provide stable fixation of the intraarticular fragments and rigid anchorage to the plates (Fig. 22-4). 1. Two distal screws, one medial and one lateral, are inserted using a targeted drill guide. As stated earlier, the screws should be as long as possible, pass through as many fragments as possible, and engage in the opposite column. Before screw insertion, a large bone clamp is used to compress the intra-articular fracture lines, unless there is a gap in the articular surface. This ensures interfragmentary compression without the need for lag screws.

STEP 4. SUPRACONDYLAR COMPRESSION The plates are then fixed proximally under maximum compression at the supracondylar level (Fig. 22-5A and B).

Chapter 22 Current Concepts in Fractures of the Distal Humerus

341

Step 3

FIGURE 22-4

Step 3. Screws are inserted through hole #1 of the lateral plate and across the distal articular fragments from lateral to medial, and tightened. This step is repeated on the medial side, using hole #3. In young patients, 3.5-mm cortical screws are used (to prevent breakage), whereas long 2.7-mm screws are used in patients with osteoporotic bone. The distal screws should be as long as possible, passing through as many fragments as possible, and engaging the condyle or epicondyle of the opposite column.

1. The slotted proximal screw on one side is backed out, and a large bone clamp is applied distally on that side and proximally on the opposite cortex to eccentrically load the supracondylar region. A second proximal screw is inserted through the plate in compression mode and then the screw in the slotted hole retightened. Care should be taken not to change the varus-valgus or rotational alignment of the articular surface when the bone clamps are applied. 2. The same steps are followed on the opposite side. Following this step the fixation should be stable. 3. The remaining diaphyseal screws are then introduced, providing additional compression as a result of the undercontoured plates being pulled down to the underlying bone. To avoid having the screws strip the bone, this last step is best performed by squeezing the plates against the bone with a large clamp rather than relying on the screws to deform the plates.

Step 4A

A

B

Step 4B

FIGURE 22-5

Step 4. A, Using a large tenaculum to provide interfragmentary compression across the fracture at the supracondylar level, the lateral column is fixed first. A screw is placed in dynamic compression mode (inset) in hole #4 of the lateral plate. Tightening it further enhances interfragmentary compression at the supracondylar level (converging arrows) to the point of causing some distraction at the medial supracondylar ridge (diverging arrows). B, The medial column is then compressed in a similar manner using the large tenaculum, and a screw is inserted in the medial plate in dynamic compression mode. If the plates are slightly undercontoured, they can be compressed against the metaphysis with a large bone clamp, giving further supracondylar compression.

STEP 5. FINAL FIXATION

DEALING WITH METAPHYSEAL BONE LOSS

The smooth Steinmann pins are removed, and then the remainder of the screws are inserted (Fig. 22-6). The intraoperative elbow motion should be full unless significant swelling has already developed. One deep and one subcutaneous drain are placed during the closure. The skin should be closed with staples or interrupted sutures.

Adequate bony contact with interfragmentary compression in the supracondylar region is necessary to ensure the stability of the construct and eventual fracture union. If metaphyseal bone loss or comminution precludes an anatomic reconstruction with satisfactory bony contact, the humerus can be shortened at the metadiaphyseal fracture site, provided that the overall alignment and

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Part V Adult Trauma

Step 5

FIGURE 22-6

Step 5. The smooth Steinmann pins are all removed and the remainder of the screws inserted. The distal screws interdigitate for maximum fixation in the distal articular fragments (as described in Fig. 22-1).

geometry of the distal humerus is correct. We refer to this alternative reconstructive technique as supracondylar shortening (Fig. 22-7A to G). This technique is especially useful in cases of combined soft tissue and bone loss. Shortening by 1 cm or less has only a slight effect on triceps strength in terminal extension,6 and in cases of severe soft tissue and bone loss, up to 2 cm of shortening can be tolerated without serious disturbance of elbow biomechanics.6

POSTOPERATIVE MANAGEMENT Immediately after wound closure, the elbow is placed in a bulky noncompressive Jones dressing with an anterior plaster slab to maintain full extension and the upper extremity is kept elevated for 3 days or more, depending on the extent of soft tissue damage. Those fractures with severe soft tissue damage, which include most open fractures and high-energy closed fractures, are immobilized and elevated in elbow extension for 3 to 7 days postoperatively. While elevated, the limb is let down for a few minutes once or twice each hour to permit

shoulder movement, to relieve discomfort, and to prevent perfusion disturbance. Closed fractures without severe swelling or fracture blisters are removed from the Jones dressing after 3 days, and a nonconstrictive elastic sleeve is applied over an absorbent dressing placed on the wound. A physical therapy program including active and passive motion is then initiated. All patients are permitted active use of the hand and instructed not to lift (or push or pull) anything heavier than a glass of water or a telephone receiver for the first 6 weeks. No form of external protection, such as casts or braces is needed if the technical objectives have been achieved. If postoperative motion fails to progress as expected, a program of patient-adjusted static splinting is instituted as soon as the soft tissues are healed. The torque across the elbow applied with such a patient-adjusted splint was low enough to cause discomfort but not pain, and therefore not of concern with regard to the security of the fracture fixation. Continuous passive motion (CPM) is helpful in speeding the recovery of motion if the soft tissues will tolerate CPM. In cases of severe soft tissue trauma, it may be wise to postpone or avoid using CPM.

STRUCTURAL STABILITY VERSUS FRACTURE STABILITY I wish to emphasize that this principle-based technique is not just a different method of fracture fixation. It is a whole new concept based on the idea that stability of the distal humerus is achieved by the creation of an architectural structure. The bone fragments rely on their integration with the whole structure for stability, rather than on fixation of each bone fragment by screw threads. The concept is borrowed from modern architecture and the application of civil engineering principles to surgery. The interdigitation of screws within the distal segment rigidly attaches the articular fragments to the shaft by linking the two columns together. This permits stability to be achieved in such cases as low transcondylar (Fig. 22-8A to D) or severely comminuted (Fig. 22-9A to D) fractures. The concept follows the architectural principles of an arch, in which two columns are anchored at their base (on the shaft of the humerus) and linked together at the top (long screws from the plates on each side interdigitating within the articular segment). The interdigitation is best achieved by contact between the screws. However, multiple screws separated by small gaps within the bone will function as a “rebar” construct (steel rods inside concrete). Fixation of the bone fragments is thus reliant not on screw purchase in the bone, but on the stability of the hardware framework, in just the same way that a modern building derives its stability from the grid

Chapter 22 Current Concepts in Fractures of the Distal Humerus

343

Fragment rotation

A

B

C

E

D

H

I

F

G

FIGURE 22-7

In cases of supracondylar bone loss, and in some cases of severe comminution, anatomic placement of the distal humerus with respect to the shaft would leave a large structural defect in one or other column, and only point contact in the other. In such cases when structural bone graft is not an option, a supracondylar shortening osteotomy can be performed. A, This involves reshaping the distal end of the shaft (dark lines) (never the articular segments) to enhance contact between the distal articular segment and the shaft. Usually, only a small amount of bone is resected from the distal end of the shaft, and sometimes from one side of it as well (for side-to-side apposition and compression). B and C, The limb is shortened through the fracture site to permit interfragmentary compression between the trochlea and the distal shaft, between the capitellum and the distal shaft, and side to side on one or both sides. Once these surfaces have been compressed and fixed with the plates, stability is strong enough to permit immediate motion and rehabilitation. It is acceptable to translate the distal segment medially or laterally, and also slightly anteriorly, provided that rotational and valgus alignment is maintained. D to G, Preoperative and most recent radiographs of a severe distal humerus fracture with substantial bone loss that was treated with shortening. H and I, Elbow range of motion at most recent follow-up was 0 to 150 degrees.

work of steel assembled and bolted or welded together inside its walls and columns. The screws in the distal segment are converted into fixed angle screws by two of the technical objectives. First, several long screws in the distal fragments lock together by interdigitation. Second, these screws pass through a plate on one side and into a bone fragment

on the other side that itself is also anchored by a plate. From an engineering perspective, this technique of creating fixed angle screws enhances fixation in the distal fragments. It also permits rigid linkage and compression between the distal segment and the shaft. The combined use of clamps, strong and slightly undercontoured plates, dynamic compression holes, and selected metaphyseal

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C

A

B D FIGURE 22-8

Low supraintercondylar fractures through osteopenic bone (A and B) require placement of the plates distal enough to allow secure fixation. Excellent stability can still be obtained with the technique of parallel plating, employing a medial plate that is contoured around the epicondyle onto the medial side of the trochlea along with a lateral plate (C and D).

Chapter 22 Current Concepts in Fractures of the Distal Humerus

A

345

C

D B FIGURE 22-9

A severely comminuted fracture (A and B) that healed uneventfully after open reduction and internal fixation. C and D, Fine-threaded K-wires, fully embedded in the bone, were used to assemble the articular fragments, just as dowels are used when pieces of wood are glued together to make furniture.

shortening provides interfragmentary compression at the supracondylar level. The stability of the construct is such that a rehabilitation program can be commenced in the immediate postoperative period without fear of hardware failure.

Role of Locking Screws Although fixed angle locking plates are available, I prefer to use variable angle locking screws (TAPLOC Acumed, Hillsboro, OR) for the distal segment to prevent the problem of incorrect screw positioning due to the fixed

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angles predetermined other plate designs. With the use of locking screws, fewer screws are thought necessary. However, based on my experience, and that of colleagues, I do not believe that locking screws are necessary if the principles and technical objectives for structural stability are achieved.

POTENTIAL COMPLICATIONS The main complications that have been reported after internal fixation of distal humerus fractures are residual decreased range of motion, fixation failure with nonunion or malunion, nerve dysfunction, extensor mechanism dysfunction, post-traumatic degenerative changes, wound and skin problems, and avascular necrosis.1,2,4,5,7-9,20 The combination of ischemic skin and a subcutaneous hematoma is an indication for surgical lavage and reclosure of the wound. With the internal fixation technique described earlier, we have experienced only one case of fixation failure in the past two decades. A 3.5 reconstruction plate experienced fatigue fracture 6 months after surgery in a patient with a severe open injury treated by supracondylar shortening and flap coverage. The lateral column had healed, necessitating only refixation and bone grafting of the medial column, which did result in union. His final range of motion was 20 to 120 degrees. Decreased range of motion may occur secondary to heterotopic ossification, intra-articular adhesions, or capsular contracture. If heterotopic ossification prevents recovery of motion, the patient may require excision of the heterotopic bone and a capsular release that can be performed 3 to 6 months after the surgery. If the surgery is performed later, the hardware can be removed if the fracture is completely healed. However, if it is removed too early, refracture may occur. Dysfunction of the extensor mechanism may occur if the triceps tendon fails to heal to the olecranon. Careful attention to reattachment of the extensor mechanism at surgery should help prevent this complication. The reconstruction should be solid enough to allow passive elbow flexion. Weakness does not seem to be a major problem with use of the TRAP approach for distal humerus fractures although it has not been specifically evaluated. Should discontinuity or subluxation of the extensor mechanism occur, it can be surgically treated by primary repair or augmentation with an Achilles tendon allograft. Olecranon nonunion can be treated by plate fixation and bone grafting. Joint deterioration may be secondary to the cartilage damage sustained at the initial injury or the avascular necrosis secondary to the devascularization of some articular fragments in severely comminuted injuries.

We have had one case of severe osteonecrosis in a severe multifragmentary fracture. To minimize the likelihood of this complication, it is necessary to leave all soft tissues attached to the distal fragments during surgery. Some cases of osteonecrosis may actually represent mechanical destruction due to instability of one or more articular fragments. It can be expected that if a fragment is mobile, it will cause progressive bone erosion.

PITFALLS AND TIPS One pitfall to avoid is the placement of a free screw into the distal fragments prior to application of a plate. Such a screw does not contribute to supracondylar stability (principle #2) and is not as secure as it might have been if it had passed through a plate (principle #1). It also potentially interferes with the passage of the screws through the plate into the distal articular segment. Another pitfall is the inappropriate placement of K-wires for provisional fixation. These should be placed in the subchondral region rather than in the center of the articular segments where the screws will go. They also need to be placed where they will not interfere with the plates. Anticipating where the plates will be positioned on the bone before placing the temporary K-wires avoids this problem. Some surgeons experience difficulty with placement of the distal articular screws through the plates and across to the other side without violating the joint or the olecranon fossa. This maneuver is facilitated by the use of a targeted drill guide and by waiting to replace the 2 or 2.5 mm Steinmann pins in the distal articular segments until after having placed at least one screw through a second hole of each plate. These pins reserve a pathway for screws to be placed across the distal segment from each side. They also are easy to drill past and place a screw past, whereas if they are replaced by screws immediately, the subsequent drilling is rendered more difficult by the larger diameter screw. Moreover, when drilling through the distal segment, a drill bit may be prone to hitting a screw and break. This problem can be avoided by drilling with the drill on reverse or by drilling with a smooth Steinmann pin; the pin will tend to deflect off a screw rather than breaking. With respect to the soft tissues, a common pitfall and misunderstanding is the assumption that the technique of parallel plating requires additional soft tissue stripping. Although the lateral skin flap must be raised around to the lateral supracondylar ridge and the lateral epicondyle, there is no additional stripping of the deep soft tissues from the lateral column compared to traditional plating of a distal humerus fracture. In all circumstances, the soft tissues should be retained on the articular fragments.

Chapter 22 Current Concepts in Fractures of the Distal Humerus

Excessive contouring of the distal end of the lateral plate can cause entrapment of the common extensor origin or lateral collateral ligament complex. This can result in loss of motion and even necrosis of the underlying soft tissues. This is avoided by placing the plate such that it stops at the epicondyle rather than distal to it and by ensuring that the plate does not wrap around the epicondyle and compress the soft tissues. This will give the appearance on the postoperative radiograph of the tip of the plate sitting away from the bone, but this

space is required to accommodate the soft tissues under the plate. The single biggest impediment to successful application of this principle-based technique is the misconception that plates must be applied in two perpendicular planes. Although that used to be true when very weak 3.5 one-third tubular plates were used, it most certainly is not true when strong plates are used. The “parallel” double-plate construct has been shown to provide excellent stability even in the presence of supracondylar

A

B

FIGURE 22-10 Lateral column failure (varus). A, Failure fixation often occurs in the lateral column through repetitive gravitational forces that apply repetitive varus stress across the elbow. If the anteroposterior radiograph of the elbow is turned horizontally, one can readily appreciate the way in which varus stresses are applied. B, This mechanism of failure can be minimized by placing the lateral column plate in the sagittal plane on the lateral surface and having the screws pass all the way through to the medial side. C, With the elbow flexed to 90 degrees, varus stresses pull the lateral column and capitellum away from the posterior plate on the lateral column. Screw failure is by direct pullout from the soft and/or comminuted bone.

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C

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gaps.18 In fact, Schemitsch et al.18 showed that the combination of a medial reconstruction and lateral DuPont plate in parallel planes was stronger than two reconstruction plates placed in two planes 90 degrees to each other, as is recommended by the AO/ASIF group and currently employed by most surgeons. When failure occurs, it is likely to start in the lateral column. With only one to three short screws into the capitellum, it can pull away from a posteriorly placed plate (Fig. 22-10A to C). We strongly recommend the use of this technique for comminuted distal humerus fractures, and prefer its use routinely for less complex fractures as well, because the stability is such that intensive rehabilitation is possible. However, for noncomminuted fractures in good quality bone, either technique can be used reliably. The efficacy of this approach to achieving structural stability was conclusively documented in a series of 32 consecutive complex distal humeral fractures.16 Twentysix fractures were AO type C3, and 14 were open. Despite extensive comminution, bone loss, osteoporosis, or open wounds, neither hardware failure nor fracture displacement occurred in any patient. Union of 31 of the 32 fractures was achieved primarily. No patients required surgery to treat elbow stiffness unless heterotopic ossification had formed. There was one deep infection that resolved without hardware removal and did not impede union. At the time of the most recent followup, 28 elbows were either not painful or only mildly painful, and the mean flexion-extension arc was 99 degrees. In summary, this principle-based approach to achieving “structural stability” in distal humerus fractures has many advantages. Complex fractures are able to be fixed with sufficient stability to permit immediate intensive rehabilitation. Some fractures that have been thought to be unfixable have been very satisfactorily fixed by applying the principles outlined herein. More straightforward fractures are easily fixed using the same techniques. In our experience, the stability achieved with this approach is so much greater than that with traditional methods of fixing distal humerus fractures that bone graft has only very rarely been required, despite the severity of injuries so typical of the tertiary referral nature of our practice.

References 1. Ackerman, G., and Jupiter, J. B.: Non-union of fractures of the distal end of the humerus. J. Bone Joint Surg. 70-A:75, 1988. 2. Gabel, G. T., Hanson, G., Bennett, J. B., Noble, P. C., and Tullos, H. S.: Intraarticular fractures of the distal humerus in the adult. Clin. Orthop. Rel. Res. 216:99, 1987.

3. Helfet, D. L., and Hotchkiss, R. N.: Internal fixation of the distal humerus: A biomechanical comparison of methods. J. Orthop. Trauma. 4:260, 1990. 4. Henley, M. B., Bone, L. B., and Parker, B.: Operative management of intra-articular fractures of the distal humerus. J. Orthop. Trauma 1:24, 1987. 5. Holdsworth, B. J., and Mossad, M. M.: Fractures of the adult distal humerus. J. Bone Joint Surg. 72-B:362, 1990. 6. Hughes, R. E., Schneeberger, A. G., An, K. N., Morrey, B. F., and O’Driscoll, S. W.: Reduction of triceps muscle force after shortening of the distal humerus: a computational model. J. Shoulder Elbow Surg. 6:444, 1997. 7. John, H., Rosso, R., Neff, U., Bodoky, A., Regazzoni, P., and Harder, F: Operative treatment of distal humeral fractures in the elderly. J. Bone Joint Surg. 76-B:793, 1994. 8. Jupiter, J. B., Neff, U., Holzach, P., and Allgower, M.: Intercondylar fractures of the humerus. J. Bone Joint Surg. 67A:226, 1985. 9. Letsch, R., Schmit-Neuerburg, K. P., Sturmer, K. M., and Walz, M.: Intraarticular fractures of the distal humerus. Surgical treatment and results. Clin. Orthop. Rel. Res. 241:238, 1989. 10. O’Driscoll, S.: The triceps-reflecting anconeus pedicle (TRAP) approach for distal humeral fractures and nonunions. Orthop. Clin. North Am. 31:91, 2000. 11. O’Driscoll, S. W.: Optimizing stability in distal humeral fracture fixation. J. Shoulder Elbow Surg. 14(1 Suppl S):186S, 2005. 13. O’Driscoll, S. W., Jupiter, J. B., Cohen, M. S., Ring, D., and McKee, M. D.: Difficult elbow fractures: pearls and pitfalls. Instr. Course Lect. 52:113, 2003. 12. O’Driscoll, S. W., Sanchez-Sotelo, J., and Torchia, M. E.: Management of the smashed distal humerus. Orthop. Clin. North Am. 33:19, 2002. 14. Ring, D., and Jupiter, J. B.: Fractures of the distal humerus. Orthop. Clin. North Am. 31:103, 2000. 15. Sanchez-Sotelo, J., Torchia, M., and O’Driscoll, S. W.: Principle-based internal fixation of distal humerus fractures. Tech. Hand Up. Extrem. Surg. 5:179, 2001. 16. Sanchez-Sotelo, J., Torchia, M. E., and O’Driscoll, S. W.: Complex distal humeral fractures: internal fixation with a principle-based parallel-plate technique. J. Bone Joint Surg. Am. 89:961, 2007. 17. Sanchez-Sotelo, J., Torchia, M. E., and O’Driscoll, S. W.: Complex distal humeral fractures: internal fixation with a principle-based parallel-plate technique. J. Bone Joint Surg. Am. 90(Suppl 2):31, 2008. 18. Schemitsch, E. H., Tencer, A. F., and Henley, M. B.: Biomechanical evaluation of methods of internal fixation of the distal humerus. J. Orthop. Trauma 8:468-475, 1994. 19. Self, J., Viegas, S. F., Buford, W. L., and Patterson, R. M.: A comparison of double-plate fixation methods for complex distal humerus fractures. J. Shoulder Elbow Surg. 4:11, 1995. 20. Sodergard, J., Sandelin, J., and Bostman, O.: Postoperative complications of distal humeral fractures. 27/96 adults followed up for 6 (2-10) years. Acta Orthop. Scand. 63:85, 1992.

Chapter 23 Nonunion and Malunion of Distal Humerus Fractures

CHAPTER

23

Nonunion and Malunion of Distal Humerus Fractures Joaquin Sanchez-Sotelo

INTRODUCTION Nonunion and malunion are two of the most common and challenging complications of distal humerus fractures. Newer internal fixation principles and techniques have improved our ability to achieve stable fixation of complex distal humerus fractures18 (see Chapter 22, Current Concepts in Fractures of the Distal Humerus). However, some fractures will fail to unite, leaving the patient with an unstable, dysfunctional, and oftentimes painful upper extremity requiring additional surgery. Distal humeral malunion is well characterized in the pediatric population after supracondylar fractures (see Chapters 14 and 15) but has not been analyzed as extensively in the adult population.4,8 This chapter reviews the prevalence, risk factors, pathology and treatment options for distal humeral nonunions and the clinical relevance and treatment options for distal humeral malunion.

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extensive comminution or when suboptimal fixation techniques are used. Other risk factors for fracture nonunion include smoking, use of immunosuppressive medications, severe associated soft tissue injuries, osteopenia, and poor compliance with postoperative instructions.

PATHOLOGY Distal humeral nonunions share a constellation of pathologic findings that need to be addressed at the time of surgery (Fig. 23-1). The nonunion is usually located at the supracondylar level; most of the time, the distal fragments heal in a more or less anatomic position. Progressive bone reabsorption at the nonunion site may lead to severely compromised bone stock. Previously placed hardware may compromise bone stock even further, especially when screw loosening results in a windshield-wiper effect. Additionally, severe stiffness develops, and when the patient tries to flex and extend the elbow, most motion occurs through the nonunion site, not through the joint.7 Failure to release the associated elbow contracture at the time of fixation of the nonunion may contribute to failure; otherwise, when elbow motion is rehabilitated excessive loads are transmitted through the nonunion site. Not uncommonly, ulnar nerve excursion is compromised by scarring, especially when there has been previous surgery. Excessive motion at the nonunion site may further compromise the function of the ulnar nerve by stretching. Attention should be paid to the ulnar nerve at the time of surgery.

EVALUATION AND TREATMENT OPTIONS History and Physical Examination

DISTAL HUMERAL NONUNION PREVALENCE AND RISK FACTORS Distal humerus nonunion with hardware failure and fracture redisplacement usually presents within the first few months after surgery. The prevalence of hardware failure is difficult to determine, because in some cases, hardware failure may allow ultimate fracture healing with residual secondary displacement. In addition, some potential failures of fixation may be avoided by prolonged postoperative immobilization, leading to fracture healing but very limited motion. Nonunion or hardware failure have been reported in approximately 8% to 25% of recent series on distal humerus fractures.6,9,14,19,20 In our experience, poor initial fracture fixation is the most common risk factor for fracture nonunion. Stable fixation is difficult to achieve, especially in fractures with

The history and physical examination should help delineate the details of the initial injury and subsequent treatment attempts. Risk factors for bone nonunion should be identified, including smoking and use of medications that may inhibit bone formation. It is also important to document the location and status of previous skin incisions, identify the location and ulnar nerve, and examine the neurovascular function of the upper extremity. Patients should be specifically questioned about symptoms or signs of infection after previous surgeries.

Imaging Studies When possible, sequential radiographs should be evaluated to understand the initial fracture pattern, assess the quality of the initial fixation when previously attempted, and determine the amount of bone loss. Recent radiographs will help determine the feasibility of repeated internal fixation versus

Simple Radiographs

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A FIGURE 23-1

Anteroposterior radiograph of a patient with a distal humerus nonunion after failed internal fixation. Bone stock is compromised by the nature of the initial injury and the effects of loose hardware.

arthroplasty and the need for structural bone graft and special tools for hardware removal. Computed tomography with three-dimensional reconstruction is an invaluable tool when repeated internal fixation is planned (Fig. 23-2), because it provides a better understanding of the remaining bone stock and any degree of associated malunion, and facilitates planning of plate and screw placement in order to achieve the maximum anchorage of the fixation devices.

Computed Tomography

Aspiration and Laboratory Studies Every patient presenting with a distal humerus nonunion and previous surgery or suspicious findings in the history or physical examination should be evaluated for infection. An abnormal cell blood count and elevated sedimentation rate and C-reactive protein should raise the possibility of infection. Aspiration of the elbow joint and the nonunion site provide invaluable information; the aspiration may be performed under fluoroscopy when access is difficult. Ideally, patients on antibiotics should discontinue their treatment between 2 and 4 weeks before the aspiration. Samples should be sent for cell count, gram stain, cultures and sensitivities.

B FIGURE 23-2

A, Computed tomography represents an excellent imaging modality for understanding and surgical planning in distal humerus nonunion. B, Threedimensional reconstruction may help understand rotational and angular deformities and assist in proper reduction at the time of surgery.

Chapter 23 Nonunion and Malunion of Distal Humerus Fractures

INTERNAL FIXATION Internal fixation is the treatment of choice for the majority of patients presenting with a distal humerus nonunion. The goals of internal fixation are (1) to achieve an adequate reduction and stable internal fixation, (2) stimulate bone healing with bone graft or substitutes, (3) release the associated joint contracture to help achieve a functional range of motion and decrease the stresses on the fixation, and (4) protect the ulnar nerve.

Surgical Technique Surgical Approach and Ulnar Nerve Decompression Most patients with previous surgery will have a

posterior midline skin scar that may be used for the revision procedure. If the previous fixation was attempted through separate lateral and medial incisions, most of the time, it is better to ignore those and create a new posterior midline skin incision, unless the skin quality is compromised and wound problems are anticipated. Next, the ulnar nerve should be identified; when a previously transposed ulnar nerve is asymptomatic, additional nerve dissection should be avoided as long as the procedure can be performed without further nerve exposure and the ulnar nerve can be protected and reassessed at the end of the procedure. The nerve should be formally isolated and transposed when it was left in situ during previous surgeries.7 Neurolysis should be

considered in patients with a previously transposed symptomatic ulnar nerve. Several deep exposures may be used. A nonunited previous olecranon osteotomy should be used for exposure whenever present. Similarly, when a tricepsreflecting or triceps reflecting anconeus pedicle (TRAP) approach was used for previous surgeries, the same approach should be used if incomplete healing of the extensor mechanism to the olecranon is found at the time of surgery.11 For extra-articular nonunions with an intact extensor mechanism, the so-called bilaterotricipital approach (working on both sides of the triceps without violating the extensor mechanism) provides good exposure while preventing complications such as olecranon nonunion or triceps weakness (Fig. 23-3).2 Olecranon osteotomy provides an excellent exposure and is used by many surgeons for fixation of distal humerus nonunion (Fig. 23-4).15 Alternatively, a tricepsreflecting (Bryan-Morrey or Mayo-modified extensile Köcher) or TRAP approach is selected when the decision to proceed with fixation versus arthroplasty will be taken intraoperatively.3 Once the deep exposure is complete, tissue should be sent routinely for pathology and microbiology. Capsular contracture is a constant feature of distal humerus nonunions. Failure to release the contracture will limit final range of motion and

Capsular Release

FIGURE 23-3

A

B

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A, Anteroposterior radiograph showing an extra-articular distal humerus nonunion. B, These injuries can be fixed working on both sides of the triceps.

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FIGURE 23-4

Most complex distal humerus nonunions require a more extensile approach such as an olecranon osteotomy for fixation.

increase the stress transmitted to the nonunion site, which may contribute to fixation failure. The posterior capsule and posterior band of the medial collateral ligament can been accessed and resected easily through any of the posterior approaches mentioned earlier. The anterior capsule may be released through the nonunion site (Fig. 23-5). Care should be taken to identify and protect the radial and median nerves at the time of the anterior capsular release. The anterior band of the medial collateral ligament and the lateral collateral ligament complexes should be preserved, along with the muscular attachments on the medial and lateral epicondyles, which are responsible for most of the blood supply to the distal segments. The fixation technique that we recommend for internal fixation of distal humerus nonunions follows the same principles, objectives, and steps described for fixation of acute distal humerus fractures in the previous chapter (see Chapter 22).18 However, bone reabsorption at the nonunion site usually makes it difficult to apply compression at the supracondylar level if the reduction is anatomic, and the concept of metaphyseal shortening (see Chapter 22) often needs to be applied.12 Correct orientation of the distal fragment relative to the diaphysis may be difficult, especially in cases with Fixation Technique and Bone Grafting

FIGURE 23-5

The anterior elbow capsule may be resected through the nonunion site to avoid residual stiffness and decrease stress on the fixation construct.

more extensive bone loss. Care should be taken to avoid excessive flexion, extension, valgus, varus, or malrotation when the distal portion is aligned with the diaphysis. After reduction and provisional fixation of the nonunion with Kirschner wires, the quality of the reduction may be assessed under fluoroscopy, if necessary. Correct rotational alignment will place the forearm in roughly symmetrical positions with shoulder internal and external rotation. Excessive flexion or extension will shift the elbow arc into more flexion or more extension respectively. If shortening at the nonunion level is needed to achieve adequate bone contact and compression, the distal segment should be translated anteriorly to provide room for the coronoid and radial head in flexion; extension will be limited until a new olecranon fossa is recreated by excavating bone at the posterior aspect of the diaphysis. Once the reduction is considered satisfactory, the need for structural bone graft should be assessed and dealt with accordingly. Tricortical iliac crest bone graft may be needed to reconstruct large areas of bone loss. Two parallel plates are then applied medially and laterally, and fixed with multiple distal long screws, which most of the time will interdigitate and interlock, increasing the stability of the construct (Fig. 23-6). Compression at the nonunion site is achieved by a combination of maneuvers including the use of a large reduction

Chapter 23 Nonunion and Malunion of Distal Humerus Fractures

FIGURE 23-6

A

Parallel-plating internal fixation provides satisfactory stability even in cases with severe bone loss. Note the posterior to anterior screws on the lateral radiograph to fix iliac crest bone graft.

B

clamp, proximal screw insertion in the compression mode, and slight undercontouring of the plates. Cancellous bone autograft or a bone graft substitute is then placed at the nonunion site to promote bone healing. Our preference is to fashion two thin corticocancellous plates from the iliac crest and fix them with one or more screws across the nonunion site on the medial and lateral columns (Figs. 23-6 and 23-7).

Postoperative Management After closure, the elbow is immobilized with an anterior plaster splint in full extension and kept elevated to minimize postoperative swelling. Motion is initiated as soon as the condition of the soft tissues allows, provided a stable construct has been achieved. However, when fixation of a nonunion is attempted, bone healing takes precedence over motion. If the distal humerus nonunion heals with residual stiffness, contracture release is very reliable; on the contrary, if the new fixation attempt fails, progressive loss of bone stock will compromise treatment options. Continuous passive motion or patientadjusted static splints are commonly used to maintain the motion achieved at the time of surgery. When intraoperative cultures become positive a few days after internal fixation in a patient with a previously unknown infection, the patient should receive 6 weeks of intravenous antibiotic therapy, and consideration should be given to chronic oral antibiotic suppression.

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FIGURE 23-7

Intraoperative photograph showing iliac crest bone graft fixed posteriorly with screws.

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Outcome There are several studies on the results of internal fixation for distal humerus nonunions. Some articles have included a wide spectrum,5 from delayed unions and nonunions affecting one column to infected nonunions with bone loss and associated deep infection. Other authors have studied more specific group of patients, such as flail or osteochondral nonunions.16,17 It is important to understand the information summarized below as it pertains to the particular case presenting for treatment. Early treatment attempts for distal humerus nonunions were somewhat discouraging. Mitsunaga et al10 reported on 25 patients treated with internal fixation; close to 30% of the patients required additional surgery for revision fixation or bone grafting. Ackerman and Jupiter1 published a higher union rate of 94% in a series of 20 patients, but the functional results were fair or poor in 65% of the cases, and only one patient was considered to have an excellent result. The authors noted that most patients continue to have a major long-term disability despite achieving successful union. The results of internal fixation for distal humerus nonunions were improved with the introduction of better fixation constructs and attention to capsular release and the ulnar nerve.7 The more recent literature on the outcome of internal fixation for distal humerus nonunions shows improved overall results,5 but there are some specific subsets of patients in which internal fixation continues to provide suboptimal outcomes.16,17 Helfet et al5 recently published their experience with internal fixation in 52 patients presenting with a delayed union (13 patients) or a nonunion (39 patients) of the distal humerus. Most (39 patients) but not all patients had undergone previous failed surgery. There was a wide range of patterns of nonunion included in this study. Only 13 nonunions were intercondylar; the remaining were supracondylar in 27 patients, transcondylar in 6 patients, and lateral or medial condylar in 6 patients. Union was achieved in all but one patient, and the average final arc of motion was 94 degrees. However, additional surgery was performed in approximately 30% of the patients, mostly to improve motion, address the ulnar nerve, or remove prominent hardware. Ring et al16,17 have analyzed the outcome in two specific subsets of distal humerus nonunions. In their first study, these authors reported on the outcome of so-called unstable nonunions, defined as those in which the hand and the forelimb cannot be supported against gravity. Union was achieved in 12 of the 15 patients included in their study, but additional surgery was performed in six of the 12 elbows with healing, again to improve motion, address the ulnar nerve, or remove hardware. Osteochondral nonunions were addressed in a separate paper including only three patients who all

achieved union and improved motion without evidence of osteonecrosis.16,17 The Mayo Clinic experience with internal fixation and bone grafting for distal humerus nonunion using the parallel-plating technique described in this chapter has been reviewed recently in a subset of patients with low nonunions requiring shortening. Twelve patients with a low distal humerus nonunion and severe bone loss were treated with internal fixation using a parallel-plating technique, shortening of the humerus at the nonunion site, capsular release, and bone grafting. Union was achieved primarily in all cases, but two elbows developed collapse of the articular surface after union and were revised to a total elbow arthroplasty. At an average follow-up of 2.5 years, eight of the remaining patients had no pain, mean flexion was 113 degrees, and mean extension 22 degrees. Complications included deep infection in one case and heterotopic ossification requiring surgical removal in one case. The mean Mayo Elbow Performance Score was 80 points (range, 30 to 100 points); all patients had an excellent result with no complications.

Infected Nonunions The treatment of infected nonunions is challenging and should be approached individually. A staged approach is probably best for most patients with previous surgery and retained hardware or draining wounds. The first procedure should remove all foreign material and infected tissues including bone. Antibiotic-loaded bone cement beads provide a high local dose of antibiotics. In patients with severe bone loss and poor condition of the soft tissues, temporary external fixation provides adequate stability and allows better wound care. The author has no experience with external fixation as a definitive treatment modality for infected distal humerus nonunion, but its use has been reported by others. When external fixation is not used, the elbow should be kept immobilized in a cast or brace until the second procedure, and 6 weeks of intravenous antibiotics usually are recommended based on the results of the cultures and sensitivity studies. Repeat aspiration to identify residual infection is performed between 2 and 4 weeks after the antibiotic therapy is discontinued. The bone stock remaining after the débridement will largely dictate the second procedure. If bone stock is severely compromised, consideration should be given to elbow arthroplasty instead of internal fixation. The relative risk of recurrent infection after fixation or arthroplasty is unknown, but most surgeons would recommend a longer period of time between surgeries if arthroplasty is selected, owing to concerns of periprosthetic deep infection and the more predictable restoration of motion if the joint is replaced after a long period of immobilization.

Chapter 23 Nonunion and Malunion of Distal Humerus Fractures

ELBOW ARTHROPLASTY Elbow arthroplasty has emerged as a safe and effective treatment option for selected patients with distal humerus nonunion. The details regarding total elbow arthroplasty for the salvage of distal humerus nonunion are described in Chapter 59.

DISTAL HUMERAL MALUNION IN THE ADULT PATIENT The clinical features and treatment options for distal humerus malunions have been studied and reported mostly in the pediatric population, as detailed in Chapters 15 and 16. Malunion also occurs in the adult population, but there is limited information on the evaluation and treatment of distal humerus malunion in adults.4,8

EVALUATION Most patients with malunion after a distal humerus fracture present with a combination of pain and stiffness. In the absence of associated degenerative changes or other pathology, stiffness is usually much more

A FIGURE 23-8

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prominent than pain. However, pain and stiffness may be present in patients with a previous distal humerus fracture complicated by capsular contracture, heterotopic ossification, post-traumatic osteoarthritis, infection, or avascular necrosis. The evaluation of patients with a distal humerus malunion should help determine to what extent correction of the malunion is needed in order to improve pain and function. Plain radiographs are useful mostly to assess the status of the articular cartilage and identify associated pathology (Fig. 23-8). In addition, marked deformity is easily identified in plain radiographs, but computed tomography with three-dimensional reconstruction represents the ideal imaging modality to understand the deformity and determine if there is an associated nonunion of part of the articular surface, because some patients will present with a combination of nonunion on one side of the joint and malunion on the other side of the joint.8 The malunion may be mostly extraarticular, mostly intra-articular, or a combination of the two. The evaluation should be completed with studies to identify infection in patients with previous surgery, risk factors or suspicious findings on the history and physical exam.

B

Anteroposterior (A) and lateral (B) radiographs of a patient with pain and decreased motion secondary to distal humerus malunion.

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TREATMENT Patients with symptomatic distal humerus malunion may be offered several alternatives (Box 23-1). Osteotomy for correction of extra-articular and intra-articular deformities is appealing because it provides the potential to preserve the native joint and improve pain and motion. However, some patients may present with severe joint destruction not amenable to osteotomy. Arthroplasty may represent a good alternative for older patients willing to limit their upper extremity use and prevent mechanical failure. When moderate extraarticular deformity limits motion secondary to impingement of the proximal ulna and radius with the deformed distal humerus, recontouring of the distal humerus by selective removal of bone provides a reasonable alternative with relatively low morbidity. Joint fusion may be considered for patients with severe pain who are not candidates for other surgical alternatives, but most patients with limited motion secondary to a distal humerus malunion are reluctant to have their elbow fused.

Osteotomy Patients with an extra-articular malunion of the distal humerus may benefit from extra-articular osteotomy. Correction of the malunion may improve range of motion and cosmesis. In addition, varus malunion may be associated with progressive ulnar neuropathy as well as gradual attrition of the lateral collateral ligament complex and tardy posterolateral rotatory instability.13 Closing-wedge osteotomies are usually preferred because humeral shortening is relatively well tolerated. Medial or lateral translation of the distal fragment should be considered to avoid a serpentine aspect of the distal humerus. Usually, extra-articular osteotomies are performed through a bilaterotricipital approach and fixed with medial and lateral plates (Fig. 23-9). Capsular release and ulnar nerve transposition may be associated as needed.

Treatment Options for Patients with Distal Humerus Malunion

BOX 23-1

• Osteotomy • Extra-articular • Intra-articular • Combined • Arthroplasty • Distal humerus hemiarthroplasty • Total elbow arthroplasty • Recontouring of the distal humerus • Arthrodesis

Intra-articular osteotomies may be indicated when intra-articular malunion is thought to be responsible for pain or limited motion and joint salvage is not compromised by the severity of joint destruction, avascular necrosis or secondary degenerative changes. Intraarticular osteotomies usually require a more ample approach, such as olecranon osteotomy or reflection of the extensor mechanism. Care should be taken to protect the articular cartilage and bone graft is usually required to fill the defects created by correction of the deformity. Whenever an intra-articular osteotomy is performed, an alternative salvage procedure, such as interposition arthroplasty or joint replacement should be available because the degree of joint destruction is difficult to fully appreciate before surgery.

Arthroplasty Elbow arthroplasty may be considered for older patients with intra-articular distal humerus malunion and posttraumatic osteoarthritis. Elbow arthroplasty offers reliable improvements in pain and motion. However, it introduces the potential for implant-related complications, including mechanical failure. Not uncommonly, distal humerus malunion is associated with a substantial deformity; failure to achieve an adequate soft tissue balance at the time of arthroplasty may be associated with eccentric polyethylene loading and excessive early wear.

Bone Recontouring Malunion of the distal humerus into excessive extension limits elbow flexion; similarly, flexion malunion, which is less common, limits elbow extension. Elbow motion may be improved in these circumstances by removing bone from the distal humerus to accommodate the coronoid and radial head in elbow flexion or the olecranon in elbow extension. When performed through an arthroscopic approach, this procedure is associated with much less morbidity than osteotomy or arthroplasty. The technique involves the use of an arthroscopic burr to deepen the supracondylar region of the distal humerus anteriorly or posteriorly. Capsulectomy may be associated if needed to restore motion. Care should be taken not to weaken the distal humerus to the point of facilitating a postoperative fracture.

OUTCOME There is very limited information about the outcome of surgical correction of distal humerus malunion. Cobb et al4 reported on three patients treated with an intraarticular derotational opening-wedge osteotomy for a distal humerus malunion. Motion was improved in all three patients, but one required conversion to interposition arthroplasty.

Chapter 23 Nonunion and Malunion of Distal Humerus Fractures

A

C

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B

FIGURE 23-9 A, Extra-articular nonunion may be corrected with a supracondylar osteotomy. B, Intra-articular fluoroscopy showing the planned osteotomy. C, Healed osteotomy after internal fixation with two parallel plates.

More recently, McKee et al.8 reported on a heterogeneous group of 13 patients with intraarticular distal humerus malunion or nonunion following fracture. Six fractures had healed in a malunited position, two elbows presented a combination of

lateral malunion and medial nonunion, and the remaining five presented a nonunion. An intra-articular osteotomy was performed in the eight patients with malunion; results were rated as satisfactory in seven patients.

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The results of arthroplasty in patients with distal humerus malunion are difficult to dissect out of the studies analyzing arthroplasty for the sequelae of trauma (see section on arthroplasty). As noted, the main concern is the increased rate of polyethylene wear found in patients with preoperative angular deformity.

References 1. Ackerman, G., and Jupiter, J. B.: Non-union of fractures of the distal end of the humerus. J. Bone Joint Surg. Am. 70:75, 1988. 2. Alonso-Llames, M.: Bilaterotricipital approach to the elbow. Its application in the osteosynthesis of supracondylar fractures of the humerus in children. Acta Orthop. Scand. 43:479, 1972. 3. Bryan, R. S., and Morrey, B. F.: Extensive posterior exposure of the elbow. A triceps-sparing approach. Clin. Orthop. Rel. Res. 166:188, 1982. 4. Cobb, T. K., and Linscheid, R. L.: Late correction of malunited intercondylar humeral fractures. Intra-articular osteotomy and tricortical bone grafting. J. Bone Joint Surg. Br. 76:622, 1994. 5. Helfet, D. L., Kloen, P., Anand, N., and Rosen, H. S.: Open reduction and internal fixation of delayed unions and nonunions of fractures of the distal part of the humerus. J. Bone Joint Surg. Am. 85-A:33, 2003. 6. Henley, M. B.: Intra-articular distal humeral fractures in adults. Orthop. Clin. North Am. 18:11, 1987. 7. Jupiter, J. B., and Goodman, L. J.: The management of complex distal humerus nonunion in the elderly by elbow capsulectomy, triple plating, and ulnar nerve neurolysis. J. Shoulder Elbow Surg. 1:37, 1992. 8. McKee, M., Jupiter, J., Toh, C. L., Wilson, L., Colton, C., and Karras, K. K.: Reconstruction after malunion and nonunion of intra-articular fractures of the distal humerus. Methods and results in 13 adults. J. Bone Joint Surg. Br. 76:614., 1994. 9. McKee, M. D., Wilson, T. L., Winston, L., Schemitsch, E. H., and Richards, R. R.: Functional outcome following

10.

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

surgical treatment of intra-articular distal humeral fractures through a posterior approach. J. Bone Joint Surg. Am. 82-A:1701, 2000. Mitsunaga, M. M., Bryan, R. S., and Linscheid, R. L.: Condylar nonunions of the elbow. J. Trauma 22:787, 1982. O’Driscoll, S. W.: The triceps-reflecting anconeus pedicle (TRAP) approach for distal humeral fractures and nonunions. Orthop. Clin. North Am. 31:91, 2000. O’Driscoll, S. W., Sanchez-Sotelo, J., and Torchia, M. E.: Management of the smashed distal humerus. Orthop. Clin. North Am. 33:19, vii, 2002. O’Driscoll S. W., Spinner, R. J., McKee, M. D., Kibler, W. B., Hastings, H. 2nd, Morrey, B. F., Kato, H., Takayama, S., Imatani, J., Toh, S., and Graham H. K.: Tardy posterolateral rotatory instability of the elbow due to cubitus varus. J. Bone Joint Surg. Am. 83-A:1358, 2001. Pajarinen, J., and Bjorkenheim, J. M.: Operative treatment of type C intercondylar fractures of the distal humerus: results after a mean follow-up of 2 years in a series of 18 patients. J. Shoulder Elbow Surg. 11:48, 2002. Ring, D., Gulotta, L., Chin, K., and Jupiter, J. B.: Olecranon osteotomy for exposure of fractures and nonunions of the distal humerus. J. Orthop. Trauma 18:446, 2004. Ring, D., Gulotta, L., and Jupiter, J. B.: Unstable nonunions of the distal part of the humerus. J. Bone Joint Surg Am. 85-A:1040, 2003. Ring, D., and Jupiter, J. B.: Operative treatment of osteochondral nonunion of the distal humerus. J. Orthop. Trauma 20:56, 2006. Sanchez-Sotelo, J., Torchia, M. E., and O’Driscoll, S. W.: Complex distal humeral fractures: internal fixation with a principle-based parallel-plate technique. J. Bone Joint Surg. Am. 89:961, 2007. Sanders, R. A., Raney, E. M., and Pipkin, S.: Operative treatment of bicondylar intraarticular fractures of the distal humerus. Orthopedics 15:159, 1992. Soon, J. L., Chan, B. K., and Low, C. O.: Surgical fixation of intra-articular fractures of the distal humerus in adults. Injury 35:44, 2004.

Chapter 24 Radial Head Fracture

CHAPTER

24

Radial Head Fracture PART A General Considerations, Conservative Treatment, and Open Reduction and Internal Fixation Roger P. van Riet, Francis Van Glabbeek, and Bernard F. Morrey

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stances, up to about 90% of body weight can be demonstrated across the radial head.84 The greatest amount of force transmission occurs with the forearm in pronation. This is because of a screw-home mechanism that occurs during pronation with proximal radial migration. Stability Traditional force-displacement studies have attributed 30% of the resistance to valgus stress to the radial head.57,83,96 Our studies have shown no significant resistance to valgus stability when the medial collateral ligament is intact. On the other hand, if the medial collateral ligament is deficient, the radial head is an important secondary stabilizer in preventing the elbow from dislocating.85 Other investigators115 have also shown a complementary relation of the lateral collateral ligament to the competency of the annular ligament. Therefore, the radial head may be considered a secondary stabilizer to valgus stress, and it does provide an important contribution to joint force transmission (Fig. 24-1).

INCIDENCE OF FRACTURE

INTRODUCTION HISTORICAL REVIEW Before 1933,10 the literature has been well summarized by Schwartz and Young.110 The first description was probably made by Paul of Aegina (AD 625-690): “The ulna and radius are sometimes fractured together and sometimes one of them only, either in the middle or at one end as at the elbow or the wrist.”2 Early difficulty in making the diagnosis was encountered because of “thick muscle covering.”33,93 In 1891, Hoffa described two types of radial head fractures, displaced and undisplaced.55 Hoffa55 and Helferich50 recommended resection of the radial head for late deformity. Three to 4 weeks of immobilization,122 passive motion, avoidance of “operative interference,”45 removal of the fracture fragment, and excision of the entire head for severe comminution54 were all recommended in the early 1900s. The first descriptions of a successful osteosynthesis of the fractured radial head was by Albin Lambotte in 1909.71 Other pertinent contributions include the suggestion that surgery is not a matter of election but rather of selection.54 Although much subsequently has been written about this fracture, the focus has changed to the more complex fractures.16,30,67

BIOMECHANICS AND FUNCTION OF THE RADIAL HEAD Force Transmission Studies in our laboratory have shown that, under the most demanding of circum-

Fracture of the radial head and neck has been variously reported as 1.7% to 5.4% of all fractures.27,66,86 Radial head fractures occur in about 17% to 19% of cases of elbow trauma134,137 and account for about 33% of elbow fractures.77 Approximately one in three cases is associated with another injury.127 In general, about 10% to 15% of these fractures involve the neck,86,122,127 usually in children in whom the physis has not closed.15 Recent demographic data127 from our institution suggest some changes when compared with previously published reports.5,22,23,29,30,135 Gender ratio is approximately 1 : 1. The male population has more severe fracture types and more often sustain associated injuries. Compared with the literature,22,23,29,30 the age of patients sustaining radial head fractures has increased to a mean age of 45 years, 48 years old for women and 41 years for men.127 Age and Sex

MECHANISM OF FRACTURE An axial load on the pronated forearm consistently produces a fracture of the radial head similar to that seen in clinical experience (Fig. 24-2).122 Odelberg-Johnsson88 observed precisely the same effect, noting that the fracture (1) occurred with posterior subluxation of the “forearm as far as the ligaments allowed,” and (2) involved the most anterior portion of the radial head when the forearm was pronated. Because the head of the radius is eccentric to the central axis of the neck,118 the posterolateral aspect of the radial head comes into intimate

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RADIAL HEAD REMOVED Valgus instability (%)

100 80 Arc of Injury 60 40 80º

20 0 MCL intact

Fracture

MCL released

35°

FIGURE 24-1

Relative contribution of radial head and medial collateral ligament to resist valgus stress. These data define the radial head as a secondary stabilizer to resist valgus stress.

Component

Arc

Coronoid

0-35º

Radial Head/Neck

0-80º

0º

FIGURE 24-3

Laboratory data reveal that either the coronoid or the radial head may be fractured with an axial load in extension. With increasing flexion, the radial head is selectively fractured. (Modified from Amis, A. A., and Miller, J. H.: The mechanisms of elbow fractures: An investigation using impact tests in vitro. Injury 26:163, 1998.)

ASSOCIATED INJURIES CONCURRENT FRACTURES ABOUT THE ELBOW

FIGURE 24-2

The mechanism of injury of most radial head fractures is a fall on the outstretched hand with the elbow partially flexed and pronated. A variable amount of valgus force accounts for the associated injuries that are occasionally seen.

contact with the capitellum during pronation. The common occurrence of an anterolateral fracture fragment supports this theory.29,66 A direct blow is another uncommon cause of radial head fracture.29,41 Amis and Miller3 recently enhanced our understanding of this and other fractures by correlating the fracture and the angle of flexion (Fig. 24-3). As is seen experimentally, either the coronoid or radial head may be fractured with the elbow in full extension, but the radial head can be fractured at greater degrees of flexion, approaching 80 degrees of the flexion arc.

Based on our assessment of 333 radial head fractures seen at the Mayo Clinic, we observed that the likelihood of associated injuries strongly correlates with the severity of the radial head fracture.127 The incidence of associated injuries increases from 20% in nondisplaced fractures to 80% in comminuted radial head fractures. The vast majority of these injuries (90%) are fractures about the elbow, mostly articular surface lesions. Approximately 20% of these articular injuries include the distal humerus, whereas in more than 90%, the proximal ulna is involved. Fractures or cartilage injuries of the capitellum are common101,133 but not always appreciated.19 The associated fracture of the capitellum has been studied in some detail by Ward and Nunley.132 About one half of capitellar fractures were shown to have associated radial head fractures, whereas approximately 2% of radial head fractures had associated capitellar fractures. Thus, this combination is rather rare.127,132 Fracture of both the olecranon and the radial head is usually considered a variety of the Monteggia fracture and has been analyzed in detail by Scharplatz and Allgower108 and others.44,70,94,112 In 15% of patients, the radial head fracture is complicated by a coronoid fracture.127 Fractures of the coro-

Chapter 24 Radial Head Fracture

noid have been discussed in detail by Regan and Morrey.100 If the fragment is large, significant elbow instability may occur.47,101,112 In our series, an elbow dislocation was found in about 15% of radial head fractures,127 as compared with approximately 10% quoted in the literature.1,7,27,29 Combined radial head and coronoid fractures are commonly seen in elbow dislocations. The coronoid process is involved in 80% of patients that sustain a radial head fracture as part of an elbow dislocation. Bilateral radial head fractures are uncommon and occur in about 2% of patients.29,127

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positive arthrographic findings in 4% of type I, 21% of type II, and 85% of type III injuries. Using magnetic resonance imaging in patients with types II or III radial head fractures, Itamura and associates63 recently found lesions in the medial collateral ligament in 54%, lateral ulnar collateral ligament in 80%, and lesions of both ligaments in 50%. This suggests that many ligamentous lesions remained subclinical. Unless formal examinations are used, associated ligamentous lesions may be undetected immediately and may predispose patients to develop chronic symptoms. The management of ligamentous injuries is discussed separately.

LIGAMENTOUS INJURY AT THE ELBOW Some degree of ligamentous injury often occurs with radial head fracture; this association is not always fully appreciated (Fig. 24-4).17,49,65,88,133 An incompetent ulnar collateral ligament is suggested by an increased valgus position.22,86,109 Approximately 50% of associated lesions to the elbow involve clinically significant ligamentous injuries. About 10% of patients are diagnosed with a lateral or medial collateral ligament rupture, or a combination of both.127 These clinically relevant injuries are markedly less common than previously described. Wagner130 observed 24 patients with calcification in the medial collateral ligament, and Arner and associates5 described a 12% incidence of ulnar collateral ligament calcification. Arvidsson and Johansson6 found ligament or capsular disruption by arthrography with various types of radial head fractures. Johansson65 demonstrated

OTHER INJURIES About 10% of patients with a radial head fracture sustain associated injuries other than elbow injuries. Fractures of the hand or wrist are found in about 6%.127 Conversely, radial head fractures are found in 6% of all scaphoid fractures.136 Shoulder injuries are uncommon (2%) and are usually found in nondisplaced radial head fractures.127 A ligamentous injury sustained at the distal radioulnar joint at the time of the radial head fracture15,28,116 is diagnosed in less than 1% of acute cases128 but is well recognized as the Essex-Lopresti injury and has been the subject of several reports.36,46,124 Shortening of 5 to 10 mm can be anticipated (Fig. 24-5).46 Open reduction and internal fixation to stabilize the proximal radius is recommended. Trousdale and associates125 reviewed Mayo experience with 20 patients. Fifteen had radial

FIGURE 24-4

A, Radial neck fracture that developed nonunion. B, Resection of this fracture unmasked an associated medial collateral ligament disruption with resulting symptomatic unstable elbow.

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FIGURE 24-5 A, Fracture of the radial head treated without surgery. B, Widening of the distal radioulnar joint was present after the fracture had healed. C, The radial head was removed, and 5 mm of proximal migration occurred during the next 2 years (D).

Chapter 24 Radial Head Fracture

head resection without knowledge of the wrist injury. Such late detection was treated by reconstructive procedures, with a success rate of only 14%. Proper initial diagnosis was associated with an 80% satisfactory outcome and early treatment.

NEUROVASCULAR COMPLICATIONS The uncomplicated fracture of the radial head is rarely associated with any neurovascular symptoms. Severe anterior displacement may affect the radial nerve, and a rare case of posterior interosseus nerve injury has been described in the literature.121

MUSCULAR INJURY By definition, elbow dislocation must violate the brachialis muscle, and this factor is thought to be an important variable in the development of myositis ossificans.75,123 The significance and management of this complication are discussed later in this book.

CLASSIFICATION OF FRACTURE The first classifications of radial head fractures were described by Speed in 1924117 and Eliason in 1925.37 A year later, Cutler reported a second classification29 and this presented the basis for all currently used classifications. The most commonly used classification of radial head fracture is that proposed by Mason (Fig. 24-6).77 A fourth type, the fracture dislocation, was added by Johnston.66 In 1962, Johansson65 added the degree of displacement to his classification and this was later combined with the original Mason classification to form the most recent adaptation of the original Mason classification.57

TYPE I

A

MAYO MODIFICATION OF MASON CLASSIFICATION In the previous versions of this book, Morrey added a degree of sophistication to Mason’s classification of radial head fractures by dividing them into simple and complex fractures, depending on associated lesions.81,82 However, the division between simple and complex fractures can sometimes be difficult, for example, when suspected ligamentous lesions are not formally investigated due to the limited clinical implications. Therefore, based on our clinical experience of more than 333 cases, we propose to add a suffix to the original fracture type in order to quantify associated lesions about the elbow.129 A suffix m is used if a medial collateral ligament injury is suspected or proven, but this has questionable impact on elbow stability. A capital M is used if there is an impact on stability, enough to warrant treatment. For lateral ligament injuries, l and L is used respectively. The same is done to document associated fractures to the ulna (U, u) or humerus (H, h). The suffix P is used to indicate that some sort of procedure was performed (Fig. 24-7); x for excision and F for ORIF.

FRACTURE MANAGEMENT In general, the treatment of radial head fractures is based on the fracture type and the presence of any associated injury. These injuries involve the ligaments or articular elements with variable implications to prognosis and management (Fig. 24-8). Associated injuries should be treated on their own merit, and the following discussion will be limited to the treatment of the radial head fracture as such.

TYPE II

B

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TYPE III

C

FIGURE 24-6 A to C, The Mason classification of uncomplicated radial head fractures. The exact definition of the type II fracture is often difficult to determine. Type IV is not included because it represents a complicated fracture.

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CHARACTERISTICS Type II F,m,L Mayo extended classification Definition Fracture type

I II III

Treatment

Associated lesion m l d c o

M L D C O

Radial head treatment

X F P Rx: upper case

A

C Type II m,l

FIGURE 24-7

B

Clinical findings include hemarthrosis and painful rotation of the forearm, especially with palpation of the radial head. Radiographs are not always conclusive, but an elbow fat pad effusion in an otherwise normal radiograph is indicative of an occult radial head fracture in almost 90% of patients89 (Fig. 24-9). Computed tomography scanning may give additional information on the morphology of the fracture57,126 and may aid in planning and assessing the feasibility of a surgical reconstruction (Fig. 24-10).

CONSERVATIVE TREATMENT Conservative treatment of nondisplaced53 or minimally displaced radial head fractures52 has been shown to yield good results at a long-term follow-up of 21 and 19 years, respectively. Results of conservative treatment of displaced radial head fractures are less favorable, and patients have increased pain and decreased strength when compared with surgically managed patients.68,120

A, Mayo classification of radial head fracture, which allows description of associated injuries. B, Hence, this type II fracture of the radial head with dislocation is termed II m,e. C, After treatment with open reduction and internal fixation and LCL repair it is termed II m L F.

Sedation,111 mobilization,* or immobilization with78,98,114 or without111 a plaster cast have been advocated as conservative treatment options. Minor soft tissue injuries rarely need to be addressed.65,78,135 There is little question that the type I fracture (Fig. 24-11), because of its favorable prognosis and lack of concurrent soft tissue or other osseous injury, should be managed with early motion. Mason and Schutkin,76 reporting a military experience, found a mean period of disability of 4 weeks in 18 patients treated with early motion, compared with 7 weeks in seven individuals treated with 3 weeks of immobilization. Immediate mobilization is recommended, but a delay of up to 5 days has no functional implication after a 4-week follow-up.74 The major residuum is loss of extension rather than pain.29 Mason77 reported that about one third of his 62 patients with this fracture lost an average of 7 degrees of extension. This may be associated with hemarthrosis *See references 1, 5, 7, 21, 23, 43, 65, 74, 87, 98, 111, 133, and 135.

Chapter 24 Radial Head Fracture

A

C

B

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of the joint. In a cadaveric study, McGuigan and Bookout80 demonstrated a decrease in the flexion arc of 2 degrees per milliliter fluid injected into the elbow joint. To facilitate immediate motion, aspiration of the joint, is therefore recommended32,34,40,56,97 and pain relief could be increased by infiltrating some local anesthetic into the joint.27 The most frequent complication of conservative treatment of nondisplaced radial head fractures is degeneration of the articular surfaces, which is found at long-term follow-up in about 80% of patients.52,53 Other complications include displacement or nonunion102 (Fig. 24-12).

D

FIGURE 24-8

A, Elbow stability requires articular and ligamentous integrity. B, Absence of the radial head does not cause instability if the ulnar collateral ligament and distal radioulnar joint are intact. C, Proximal migration can occur if distal ligaments are ruptured. D, Valgus laxity may be present if the ulnar ligament is violated.

FIGURE 24-9

The presence of a fat pad sign as seen here suggests an articular fracture and should be further assessed by a computed tomography study.

FIGURE 24-10 The computed tomography scan is extremely helpful to diagnose subtle associated articular injuries.

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FIGURE 24-11 A, Type I fracture involving approximately 50% of the head but with less than 2 mm of displacement. B, Minimally angulated neck fracture is also considered a type I fracture.

Delayed excision of the entire radial head can be considered only if any of these complications become symptomatic (Fig. 24-13).26,52,53,102 Among 21 patients treated with delayed excision at the Mayo Clinic, Broberg and Morrey13 reported 75% with decreased pain and 77% with improved motion. The time to delayed excision ranged from 1 month to 20 years (Fig. 24-14). A rare complication of nondisplaced radial head fractures treated conservatively is arthrofibrosis, which reportedly can be managed successfully with arthroscopic débridement.18,72

RESECTION OF THE RADIAL HEAD

FIGURE 24-12

alone.

This nonunion was asymptomatic and left

The authors consider this issue somewhat controversial and unresolved. In general, resection is reserved for uncomplicated type III fractures (Fig. 24-15). Rochwerger and colleagues104 compared the treatment of 22 type II fractures. With mean surveillance of 5 years (2 to 23 years), osteosynthesis was found to be superior to resection, as the latter had satisfactory results in just more than 50% of cases. Similar results were found in 28 patients with type III, comminuted radial head fractures. Using a meticulous surgical technique, Ikeda et al60,61 found improved results in the group treated with open

Chapter 24 Radial Head Fracture

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FIGURE 24-13 A, Type I undisplaced fracture of the left nondominant extremity in a 49-year-old man. Treatment by early motion as tolerated resulted in displacement of the fragment (B), which progressed to a nonunion (C). D, Treatment by late excision of the radial head 4 months after the fracture decreased the pain and improved pronation and supination 6 months after the procedure. (Courtesy of E. T. O’Brien, San Antonio, Texas.)

reduction and internal fixation (ORIF) over the group of patients treated with resection of the radial head. Yet, there has been a surprising resurgence of interest in the earlier treatment of choice, which is simple excision.

Janssen et al64 reported 20 of 21 excellent or good results between 16 and 30 years after excision for comminuted radial head fractures. These investigators did exclude known dislocations. On the other hand, SanchezSotelo et al106 described excision in the face of 10 dislo-

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FIGURE 24-14 A, Type II radial head fracture was treated nonoperatively. B, Persistent pain and limitation of motion resulted in a delayed excision of the radial head. The patient had a satisfactory result.

cations, which is consistent with a Mason type IV classification. In this group, nine of 10 were considered satisfactory, similar to that of Janssen. However, they did note a 5-degree increased valgus carrying angle and early asymptomatic degenerative changes of the ulnohumeral joint with a mean of about 4.5 years surveillance (Fig. 24-16). There have been other recent reports regarding excision without radial head replacement that have yielded surprisingly consistent outcomes. A study from Scandinavia of 61 resections noted that the timing of the resection, whether acute or delayed, was much less important than the Mason classification of the lesion. Similar observations were made from Asia by Ikeda, who reported good results at 10 years after 15 patients (four with type II and 11 with type II treated by excision). They did, however, notice that pain was present in about a third of these patients52a and, as noted above, favor fixation.60,61 Wallenbock et al. evaluated radial head resection in 23 instances with a mean follow-up of 17 years with personal evaluation of the entire sample. They demonstrated that 22 of 27 patients had a satisfactory outcome. They observed those with resection after a type III or IV did less well than after a type II fracture. Interestingly, there was no distinction in their group and their observations whether the patients were treated by excision in the early or in the more chronic period.131 Similarly, a report from Italy by Celli of 31 fracture-dislocations noted that only 40%

were satisfactory and 60% were unsatisfactory after various treatment options.24 This is consistent with Herbertsson’s observations that the fracture type has greater prognostic importance than the acuteness of the treatment. The basic treatment rationale, therefore, of simple resection for those fractures that cannot be reduced and fixed does have some merit. This was well summarized by Wallenbock and Potsch,131 who stated that resection is recommended “as long as there are no better longterm results of prosthetic substitution of the radial head.” We hope that prosthetic substitution will prove valuable and effective. However, realistically the long-term followup data of those treated by resection certainly justify consideration of this as a treatment option, particularly in those that do not have an associated injury.

OPEN REDUCTION AND INTERNAL FIXATION Surgical treatment of displaced radial head fractures has evolved from excision of fracture fragments or the entire head of the radius, to several techniques of ORIF and modern types of radial head replacement. ORIF was used sporadically in the past, largely because of the perception that it had “not proved successful in anyone’s hands.”98 The poor earlier results were probably due to an inadequate understanding of anatomy and less refined techniques for effective internal fixation.

Chapter 24 Radial Head Fracture

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FIGURE 24-15 A, Type III fracture demonstrating comminution. B, With long-term follow-up of 10 years, there is osteophyte formation at the ulnohumeral joint after radial head excision, but symptoms are mild. (C) The patient had no wrist symptoms.

A

B

C

The fracture fragment frequently has a periosteal hinge, indicating that its viability is possible.48 The ideal fracture for fixation is a simple, large (constituting 30% of the head) fragment that involves the anterolateral margin of the head (Fig. 24-17). However, despite the

bigger technical challenge of fixing smaller fragments, biomechanical studies have also shown a benefit of fixation of fragments smaller than one third of the radial head.8,9 The anterolateral margin of the head does not articulate with the lesser sigmoid notch; instrumented

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fixation of this fragment does not result in impingement (Fig. 24-18).20,113 If there are multiple but large fragments, open reduction can still be performed,48 but results can be disappointing.69,103 In general, experience with ORIF is satisfactory in more than 90% of cases.38,91,95,99,103,111

Geel and coworkers42 reported less than a 10-degree loss of extension and a 10-degree loss of pronation and supination in 19 patients who underwent ORIF. A similar outcome was observed by Sanders and French107 in eight patients treated for difficult type III fractures. In a study of 56 patients, Ring and coworkers103 reported excellent results in patients with minimally comminuted fractures with three or fewer articular fragments. However results were unfavorable in patients with more comminuted fractures or if the fracture was associated with an elbow dislocation. Ikeda et al62 reported excellent and good results in nine out of 10 patients, using lowprofile mini-plates for severely comminuted radial head fractures. Nine patients required hardware removal. The Herbert screw has been reported to provide virtually normal function.14 The traditional AO technique using the 2.0 or 2.7 screws has been reported as satisfactory in 100% of patients with Mason type II fractures but in only 33% of those with Mason type III fractures.69 A small buttress plate can be used for radial neck fractures.73 Esser and colleagues38 reported on 26 cases of osteosynthesis, 11 with type II and nine with type III. All were graded as satisfactory after osteosynthesis (Fig. 24-19).

FIGURE 24-16 A comminuted radial head fracture was excised in a patient with elbow dislocation. The patient had a good result 15 years after surgery but had radiographic evidence of arthritis.

LOW-PROFILE FIXATION We have recently compared the outcome of 10 patients with radial neck fracture managed by plate fixation to

FIGURE 24-17 A, Large, single fragment treated with open reduction and internal fixation (B) in a 40-year-old man. The result was classified as good, with 15 to 20 degrees of extension deficit, normal rotation and no pain.

Chapter 24 Radial Head Fracture

371

70º 120º

A

B FIGURE 24-18

A, The mechanism of slice fracture tends to shear the anterolateral portion of the head. B, This constitutes the 70 degrees of the circumference of the radial head that articulates with the lesser sigmoid fossa, which is devoid of articular cartilage. This anatomic feature allows and justifies the use of AO screws with protruding heads if the fracture is through this portion of the radius.

a comparable injury managed by a new “low-profile fixation” technique. In the latter instance, the fracture is fixed by inserting a threaded Kirschner wire (K-wire) or cannulated screw through the margin of the radial head across the fracture and engaging the opposite radial cortex (Fig. 24-20). A statistically significant better forearm arc of motion and elbow flexion arc was documented with the low-profile axial fixation technique.114 Some other technique modifications have been proposed recently. Fibrin adhesive seal was used as early as 1995, but despite excellent short-term results, this has never become a mainstream technique.4 Bioabsorbable polylactic pins have also been used since the early 1990s, for fixation of radial head fractures.51,59,92 In a recent prospective randomized study of 135 patients, results of fixation using polylactic pins have been shown to yield at least comparable results compared to other types of fixation.51 However, despite favorable results, biocompatibility may be an issue unique to this type of fixation.11,92

In comparison to resection or prosthetic replacement of the radial head, ORIF has been shown to be preferable if a stable fixation can be achieved. In a recent cadaveric study, ORIF has biomechanically been shown to be superior to resection or prosthetic radial head replacement.25 In a retrospective study by Parasa and Maffulli90 of 29 patients with radial head fractures managed with different surgical methods, ORIF showed the best results in Mason type II fractures, followed by type III. Comparing different techniques, the best outcome was observed with screw fixation, followed by excision of the radial head, K-wire fixation, partial excision, Silastic implant, and plating. One prospective study by Khalfayan and associates68 compared the results of 16 patients treated by closed reduction and 20 by ORIF. The former had only 44% satisfactory results, compared with 90% in the group treated by ORIF. Boulas and coworkers12 compared results of ORIF with resection, Silastic radial head replacement, and conservative treatment in 36

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A

B

FIGURE 24-19 Comminuted fracture of head and neck (A) fixed with mini plate and screws (B and C).

C

FIGURE 24-20

So-called low-profile fixation employs axially aligned screw fixation from the margin of the head down the shaft of the proximal radius.

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patients. The best clinical scores were found in patients treated with ORIF, and the authors recommended this type of treatment for displaced radial head fractures. Arthroscopically Assisted Reduction and Internal Fixation As has been described in intra-articular frac-

tures in other joints,125 arthroscopic techniques to reduce and fix radial head fractures are currently under development.31,105

AUTHOR’S PREFERRED TREATMENT NONDISPLACED RADIAL HEAD FRACTURES Type I fractures are treated by joint aspiration for immediate pain relief. From the author’s personal experience, the infiltration of a local anesthetic does not provide much additional relief; on the contrary, it was painful to receive a volume of fluid into the joint. A collar and cuff is given, and immediate motion as tolerated is advised. We see the patient in about 7 to 10 days and perform repeat radiographs for the rare event of secondary displacement. If so, ORIF may still be performed at this stage. We do not routinely use physical therapy in these patients.

DISPLACED FRACTURES Depending on the nature of the fracture and the presence or absence of associated injury, we tend to fix these fractures. Radial head replacement is discussed later. Evaluation of the number, size, and displacement of fracture fragments is extremely difficult from plain radiographs. The fracture and associated bony lesions are therefore routinely assessed using computed tomography (CT) scanning of the elbow (Fig. 24-21). If the displacement is more than 2 mm, ORIF is performed with headless screws or occasionally special plates (Fig. 24-22). The distal radioulnar joint injury is treated by ORIF of the radial head and may also require surgical stabilization by an open procedure or percutaneous cross-pinning to maintain radial length. Even with the aid of CT scanning, the severity of the fracture can sometimes be underestimated from imaging studies; therefore, it is our clinical practice to have screws and plates and also a prosthetic device available during surgery (Fig. 24-23). The radial head and other bony injuries are addressed first, and stability of the elbow and wrist is tested following adequate bony reconstruction. If necessary, ligamentous repair is undertaken. If the elbow remains unstable following bony and soft tissue repair, a hinged elbow external fixation device is applied.

FIGURE 24-21 The computed tomography scan accurately depicts subtle fractures and the precise amount of displacement.

Elbow flexion and extension are allowed within the first week, usually on the third or fourth day after surgery. The surgical technique is described below. Surgical Technique An extended lateral incision is made over the lateral margin of the humerus, extending over the lateral epicondyle and the radial head. The incision is carried distally, parallel to the axis of the forearm. A posterior midline incision may also be used.35 This is especially helpful if associated medial-sided injuries need to be addressed surgically. The Kocher approach between the anconeus and the extensor carpi ulnaris is the most frequently used exposure of the radiocapitellar joint. In traumatic situations, however, a musculocapsular rent is often present and should be incorporated in the approach, without further disruption of the soft tissue envelope. Care should be taken, not to disrupt the lateral ulnar collateral ligament (Fig. 24-24). Hematoma is evacuated and the forearm is rotated to expose the fragment. The forearm should be pronated, and the use of retractors behind the radial head and neck should be avoided in order to protect

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A FIGURE 24-22

A

B Fracture seen in figure is fixed with headless screw (A and B).

B

FIGURE 24-23 If the neck is involved, a mini plate may be used (A and B), but the senior author prefers low-profile fixation (see Fig. 24-20).

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Capsular incision

Radial collateral lig.

A

Lat. ulnar collateral lig.

C

the posterior interosseus nerve.119 Reduction and provisional fixation can be achieved with a 0.45 K-wire. Depending on the anatomy of the fracture and size of the fragments, one or two 2.0, 2.7 AO, or Herbert screws,14,79,91 bioabsorbable pins,51,59,92 bladeplates,103 or plates and screws62 are inserted in as perpendicular a position to the joint and fracture surface as possible.39,48,61,111 If necessary, the head is counter-sunk and care is taken to ensure that the screw tip has not violated the opposite cortex (Fig. 24-25). The lateral soft tissues, including the annular ligament are repaired, and, if no associated injuries are present, immediate motion is begun. The aim of all types of ORIF is to obtain a stable fixation that allows for immediate mobilization of the elbow joint. In radial neck fractures, plates tend to produce excessive scar formation, necessitating removal in almost all instances.61,62 If possible, we therefore avoid plate fixation and prefer “axial, low-profile” fixation for neck fractures. Our review of 24 fractures revealed a mean forearm rotation of 113 and 160 degrees for the plate plus lowprofile screw, respectively (P < .05).114 Thus, we prefer

B

FIGURE 24-24 Excision through the annular ligament must be performed proximal so as to avoid injury to the lateral ulnar collateral ligament (A). Clinical examples (B and C).

the “low-profile” screw fixation technique. The technique consists of the use of either threaded K-wires or 2.7-mm cannulated screws placed from the margin of the head, across the fracture to engage the opposite cortex (see Fig. 24-20). The development of low-profile plates such as shown in Figure 24-26 may lessen the tendency for scarring and improve forearm rotation after their use. We must await data to determine if this expectation will be realized.

TYPE III FRACTURES—AUTHORS’ PREFERENCE In uncomplicated type III fractures, we prefer complete and early excision (within 24 hours of injury), followed by active motion in 3 to 5 days if ORIF is not possible. However, fractures are (1) almost always (>80%) associated with additional articular or ligamentous injuries,127 (2) are too comminuted for fixation, and hence, are treated most commonly by prosthetic replacement, especially if the fracture consists of more than four

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Non-articular margin Countersink Forearm fully pronated

FIGURE 24-25 The head of the AO screw is countersunk to lessen the likelihood of impingement or soft tissue irritation.

A

B

C

FIGURE 24-26 The low-profile radial head/neck plate with variable angle locking screws may lessen the likelihood of postoperative scarring. (Courtesy of Small Bone Innovations, Morrisville, NJ.)

Chapter 24 Radial Head Fracture

SBI: RADIAL HEAD MANAGEMENT ALGORITHIM Acute injury

Yes

Slice Fx

References Yes