Handbook of Orthopaedic Trauma Implantology 9789811975394, 9789811975400

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Arindam Banerjee Peter Biberthaler Saseendar Shanmugasundaram Editors

Handbook of Orthopaedic Trauma Implantology

Handbook of Orthopaedic Trauma Implantology

Arindam Banerjee • Peter Biberthaler • Saseendar Shanmugasundaram Editors

Handbook of Orthopaedic Trauma Implantology With 1441 Figures and 69 Tables

Editors Arindam Banerjee NH Narayana Superspeciality and Multispeciality Hospitals Howrah, West Bengal, India

Peter Biberthaler Technical University of Munich Munich, Germany

Saseendar Shanmugasundaram Sri Lakshmi Narayana Institute of Medical Sciences Puducherry, India

ISBN 978-981-19-7539-4 ISBN 978-981-19-7540-0 (eBook) https://doi.org/10.1007/978-981-19-7540-0 © Springer Nature Singapore Pte Ltd. 2023 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Paper in this product is recyclable.

Foreword 1

This book represents an important and new compilation of relevant aspects to improve fracture healing and trauma care. It combines several areas of focus, such as conditions relevant for bone regeneration, bioengineering and biomechanics. It covers all areas of the human body that are important for orthopaedics and trauma and focuses on implants as well as options for bone grafting. Thereby, it offers a complete picture of fracture management. It is important to mention that unlike other books on musculoskeletal condition, it contains a strong focus on spinal care. The authors are to be congratulated well-rounded book that fills a gap in modern orthopaedic and trauma care. It even covers additional aspects of imaging, the future of implantology and certain aspects of elective surgeries, such as arthroplasties and paediatric management. This new contribution should be highly recommended to residents in training and in those that are keen to expand their horizon in the care of adolescent and adult patients with musculoskeletal issues. Universitätsspital Zürich Klinik für Traumatologie Zürich, Switzerland

Prof. Dr. med. Hans-Christoph Pape

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Foreword 2

I am very pleased to write this foreword to the “Handbook of Orthopaedic Trauma Implantology”, a significant work in today’s advancing medical field. This book is the first of its kind as this topic has never been addressed in orthopaedic academic literature before. The term “Implantology” in reference to orthopaedic trauma is being coined for the first time by the editors; as previously, the term was exclusively associated with dental implants. This is a book of considerable magnitude spanning more than 2100 pages, 157 international authors and 1500 illustrations (majority colored) with high quality figures and photographs. In fact, the publisher even humorously speculated whether the editors had embarked on writing the Mahabharata (an Indian epic) and doubted if it could ever be completed! I have known Dr. Arindam Banerjee for more than two decades as an academician interested in presenting new and useful works. This handbook thoroughly explores orthopaedic trauma implantology, covering all aspects comprehensively. From foundational principles to advanced technologies, it serves as a valuable reference resource. The handbook delves into the science of orthopaedic trauma implantology, examining implant design, the interplay of internal and external fixation, predicting implant failure, materials’ evolution, biomechanics and their applications in fractures. All regions of the body are systematically covered. Upper and lower limbs, spine, pelvis and pediatrics all have their separate sections. The book has also included a section on bone grafts, which though not an implant in the strictest sense of the word, is something frequently “implanted” during an operation. This book only deals with primary trauma including polytrauma and patients with multiple fractures. Revision trauma, arthroplasty or other types of implants which are not related to trauma have been deliberately left out as those segments merit separate treatises. Designed for orthopaedic surgeons, medical students, researchers and professionals, this handbook is a valuable asset. I commend the authors, editors and other contributors for their work in creating this book. As a surgeon dealing with modern trauma for the past 55 years, I have watched and participated in the progress and development of this great specialty from the time it was an approximate science to a period where perfection is the norm and not an exception. The “Handbook of Orthopaedic Trauma Implantology” will surely serve as a guiding resource for vii

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Foreword 2

current and future orthopaedic surgeons, enriching their learning journey. And it is for this reason that Springer Nature had designated it as a MRW project (Major Reference Work). I wish a grand success for this book and hope for the second edition soon as newer implants are flooding the market. Department of Orthopaedics Maharashtra University of Health Sciences Nashik, India

Prof. GS Kulkarni

Preface

This is probably the first comprehensive book on the subject of orthopaedic trauma implantology in medical literature. In fact, we believe that such a project has never been attempted before. The efforts taken in execution of this project have been Herculean. Orthopaedic surgeons and traumatologists from five continents have contributed to, conceptualized and compiled information leading to the creation of this book and making it a truly global effort. Orthopaedic Trauma Implantology (OTI) as a sub-specialty of orthopaedics is at once a science, an art as well as commerce. We need to therefore look at this subject holistically in order to understand why it stands where it stands today. Human beings (and animals) come armed with the natural capacity to repair injured bone (as well as other musculo-skeletal tissue). But the sequelae of this “natural” repair often leaves the injured portion of the skeleton in a sub-optimal state of function and structure. This is where human endeavour has stepped in. The science of implantology has allowed the healing process to be more predictable with a better outcome by restoring pre-injury anatomy and physiology and by preventing avoidable pathology. The scientific principle has been to allow nature to do its healing in a more orderly and controlled way. But the discovery of “the laws of healing” has been chaotic and painstaking, and the path to “good science” has hardly been linear. The art of orthopaedic implantology has been used to design thousands of successful and not so successful metallic (and very rarely non-metallic) frameworks to support the injured musculo-skeletal tissue. But, since the shapes of most bones are irregular, some implants are forced to be. It is important to realise that the design process has been through many a trial and error. It has had to satisfy various scientific fads and fashions which were later found to be bio-mechanically erroneous and fallacious. Or they violated or retarded the body’s “natural laws of healing”. The discovery of these “laws” was not easy. Consequently, some designs failed, driving back the designer to the drawing board for a better model. Other designs were successful from the onset, but later day innovators could still improve upon them.

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Preface

Commerce has always played a dominant role in this specialty. Very early on, entrepreneurs realised the commercial prospects of this science and therefore took an early interest in this subject. Today, the industry is worth hundreds of billions of dollars in turnover and generates countless jobs. Commerce in this discipline has acted as a two-edged sword as investment drove innovation. But it also managed to keep knowledge cloistered in the form of patents and commercial deals. This is one of the reasons that academic work in this sub-specialty has lagged behind. The objectives of this book are to chart out and document this non-linear path, to look back with hindsight and explain why and how the story evolved and to throw light on the logic behind the twists and turns and the to-ing and fro-ing of principles and designs. Our role is like a cartographer who maps out the roads of a city so that a future-day town planner can grasp the lie of the land at a glance and plan the next stage of development. This handbook has several general sections dealing with the principles of orthopaedic implantology and other regional chapters, such as upper and lower limbs, spine and pelvis. It deals with paediatrics, orthopaedic infrastructure and various ancillary services, which are essential to conduct a successful surgical implanting procedure. On this note, another important issue should be noted. Traditionally, operating surgeons have been more concerned about anatomy and pathology rather than physiology and critical care. They have also considered soft tissue as an impediment to surgery rather than an ally of healing. Any surgery is a temporary or permanent insult to biological tissue. Attempts to avoid this iatrogenic damage has a huge bearing on implant design today. In this book, we have tried to give readers a 360 view of the subject by incorporating anatomy, physiology, pathology, biomechanics, design, ancillary services and infrastructure as well as the changing dynamics of human requirements in a comprehensive collage of information. It is very important to understand that this is a book about orthopaedic trauma implantology (OTI). Each of the three words is important. It is not a book about traditional traumatology – so we have generally left out classifications of fractures or their in-depth management (including detailed operative steps). It also does not deal with tumour implants or soft tissue implants. Similarly, it also does not discuss arthroplasty implants unless required in primary trauma. Revision trauma or re-do surgery does not lie within the scope of this book. However, staged procedures for primary trauma have been included. We have also included a section on bone grafts and substitutes – which though not implants have an important role to play in trauma implantology. This book is primarily meant for the practicing orthopaedic surgeon. However, it should be of great help to academicians, students (at all levels of medical training), orthopaedic nurses and technicians. We would like to thank Springer Nature for commissioning this epic work and designating it as a MRW (Major Reference Work) as well a “living book”. On their recommendation, we have limited ourselves to what is considered accepted knowledge today and tertiary references. We have tried to avoid outlying concepts and

Preface

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implants. We hope that this handbook will help you the next time you face a question or dilemma in orthopaedic trauma implantology. Kolkata, India Munich, Germany Puducherry, India October 2023

Arindam Banerjee Peter Biberthaler Saseendar Shanmugasundaram

Background to Writing This Book on Orthopaedic Trauma Implantology

Several triggers motivated me to contemplate writing a book on the subject of orthopaedic trauma implantology. The first trigger was my extensive involvement with trauma implants between 2015 and 2018, during which I had the privilege of leading two prominent national organizations dedicated solely to trauma. While preparing scientific programs for various conferences, we consistently conducted workshops to explore the latest available implants. Some of these implants proved highly successful, while others faded into obscurity or were sidelined over time. This led me to reflect on the need to document the life history of these implants. Many of the vanished implants possessed intriguing technical innovations and unique features, but their demise resulted from various deficiencies. Often, they suffered from inadequate marketing or lacked champions to promote their adoption. Another trigger emerged from my clinical practice, where medical representatives frequently introduced me to new implants. Peer pressure compelled me to consider adapting or changing my surgical techniques, particularly in relation to femoral nails, which underwent a series of improvements over the past two decades. Whenever a new implant entered the market, older instruments would vanish. This posed difficulties when it became necessary to remove an older implant, as obtaining the required inventory for its removal proved challenging. This realization further emphasized the inadequate documentation of operative hardware. Despite thorough internet searches, academic literature on this topic was scarce. The available sources were primarily commercial catalogues. In fact, this book marks the first instance of the term “implantology” being used in the field of orthopaedics. Prior to this, the term was solely employed in dental science, without any acknowledgement of its relevance to orthopaedic advancements. During this time, Dr. Peter Biberthaler, then the President of “The Association for the Rationale Treatment of Fractures (ARTOF)”, Munich, Germany, a global trauma grouping of which I am a part, invited me to write two chapters for a book on regional trauma. This opportunity brought me into contact with Springer Nature. After careful consideration, I sent their London office a book proposal on limb trauma implantology, comprising approximately 300 pages. Their response was overwhelmingly positive, which became the final and most important trigger. Springer Nature recognized the absence of academic work on this subject and proposed that I undertake the writing of a Major Reference Work (MRW) covering xiii

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Background to Writing This Book on Orthopaedic Trauma Implantology

all aspects of trauma implantology. However, given my primary experience in limb surgery, I initially questioned whether it would be possible to undertake such a significant endeavour. As I delved deeper into this project, I began discussing it with my colleagues, mentors and peers. At this stage, several other individuals became involved. Dr. Ashok Johari took charge of Paediatric Orthopaedics, Dr. Ramesh Sen of pelvi-acetabular, Dr. Ravi Bharadwaj of upper limb, Dr. Chinmay Nath of Spine and Dr. Ujjwal Debnath suggested incorporating a section on grafts, which, although technically not implants, hold relevance to the topic. Dr. Saumitra Misra organized meetings to discuss this project with interested authors at his hospital. Dr. Debabrata Kumar took an intitiative in the table of contents (TOC) and consistently introduced me to surgeons who wanted to contribute chapters. Unfortunately, Debabrata relocated to the UK shortly afterwards and couldn’t devote as much time to us later on. However, his contact, Dr. Saseendar Shanmugasundaram, joined us online from Oman and became one of the major pillars of this venture. He soon became my co-editor and contributed significantly to the hard work behind its completion. Without his assistance, this undertaking might never have been accomplished. In addition, our long supportive families have sacrificed their personal time day-afterday so that this book could be written and edited. Other individuals who made substantial contributions include Drs. M. Shantharam Shetty, Gaur Gautam Kar, Srinivas Kambhampati, Ajit Kumar, Samundeeswari Saseendar and Shiuli Dasgupta. At the beginning of the project, Shiuli Dasgupta, an enthusiastic medical student, provided valuable assistance with computer work related to editing. Ms. Srabani Mitra, a professional artist, helped us by drawing with some of the medical illustrations. Of course, the book’s foundation lies in the brilliant chapters authored by various individuals and groups of authors. Finally, it is essential to acknowledge the support of Dr. Naren Aggarwal, who is in charge of Springer Nature’s Delhi office. When he saw the list of 114 planned chapters, he looked at me with a hint of sadness and said, “Doctor, do you realize that you are trying to write a Mahabharat (an Indian epic)? Do you think you can finish this project?” Well, Mr. Aggarwal, we have ultimately managed to do so! This achievement owes no small thanks to the excellent contributions of Springer Nature’s project managers, Mr. John Jebraj and Ms. Divya Nithyanandam. Additionally, we were aided by the COVID-19 epidemic, which afforded busy doctors more time for academic pursuits as their clinical workload reduced. Consequently, we made substantial progress during the pandemic. This proves the old adage that behind every crisis lies an opportunity! However, there is a significant gap in this project. Initially, my intention was to catalogue individual implants, similar to projects such as the global seed bank in Svalbard, Norway or the banks of microorganisms found worldwide. This book primarily focuses on generic implants and the principles of implantology. Nonetheless, it serves as a valuable starting point.

Background to Writing This Book on Orthopaedic Trauma Implantology

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Addressing the implant bank issue requires further thought, planning and, of course, funding. The primary concern is to prevent the loss of knowledge, necessitating careful storage for current and future generations. Kolkata, India

Dr. Arindam Banerjee

Contents

Volume 1 Part I General Introduction to Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2

3

4

5

6

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The Science, Art, and Commerce of Orthopaedic Trauma Implantology: How to Use This Book . . . . . . . . . . . . . . . Arindam Banerjee, Saseendar Shanmugasundaram, and Shiuli Dasgupta The Drivers of Change in Orthopaedic Trauma Implant Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arindam Banerjee, Saseendar Shanmugasundaram, and Shiuli Dasgupta

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3

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Defining the Clinical and Radiological Endpoint of a Successfully Fixed Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sriram Srinivasan, Amit Bishnoi, and Vasantha Kumar Ramsingh

35

Trying to Predict Implant Failure in Orthopaedic Traumatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nipun Rana and Shamal Das De

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Orthopaedic Nails Versus Orthopaedic Plates: An Evolutionary Tale for Dominance and Relevance . . . . . . . . . . . . . . . . . . . . . . . . Arindam Banerjee, Saseendar Shanmugasundaram, and Shiuli Dasgupta

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Internal Fixation Versus External Fixation in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rodrigo Donoso, S. Samundeeswari, and Sebastián Irarrázaval

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Predicting the Future of Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vaibhav Bagaria, Amit Sharma, and Omkar Sadigale

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Contents

Part II

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143

General Principles of Intramedullary Nailing for Long Bone Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. Shantharam Shetty

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Evolution of Intramedullary Nails for Long Bone Fractures in the Upper Limb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shailesh Pai and Muthur Ajith Kumar

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Evolution of Intramedullary Nails for Long Bone Fractures in the Lower Limb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. Shantharam Shetty and K. Yogesh

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Principles of Orthopaedic Plating . . . . . . . . . . . . . . . . . . . . . .

209

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General Principles of Orthopaedic Plating and Overview . . . . . . Shyamasunder N. Bhat and Muthur Ajith Kumar

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Conventional Orthopaedic Plating . . . . . . . . . . . . . . . . . . . . . . . . Shyamasunder N. Bhat

227

14

Orthopaedic Locking Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amrish Kumar Jha

235

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Orthopaedic Anatomical Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . Muthur Ajith Kumar and Mohamed Faheem Kotekar

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Antegrade and Retrograde Femoral Nailing Wasudeo Gadegone and Piyush Gadegone

Part III

Part IV 16

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Principles of Orthopaedic Nailing

Principles of External Fixation in Orthopaedics

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Principles and Overview of External Fixators in Orthopaedic Traumatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dipankar Sen

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Use of External Fixation in Primary Management of Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prashanth Naik, Lara Elizabeth McMillan, Badri Narayan, and Karthikeyan. P. Iyengar

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External Fixator as an Augment or Alternative to an Internal Fixator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Subrata Basu

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Principles and Usage of Ilizarov Techniques in the Management of Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chandrachur Bhattacharyya and Ravi Ganesh Bharadwaj

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Contents

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Computer-Aided External Fixation Systems in the Management of Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ishani Milind Chaudhary, Arjun Naik, Mohit Bansal, and Milind Madhav Chaudhary

Part V

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Bone Replacement in Orthopaedic Traumatology . . . . . . . . .

391

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Natural Sources of Bone Grafts Emrah Caliskan and Bulent Erol

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Techniques of Bone Grafting and Bone Augmentation Ujjwal K. Debnath, Rishi Thakral, and Zack P. Burrow

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Advances in Bone Grafting Technology . . . . . . . . . . . . . . . . . . . . Ujjwal K. Debnath

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Principles of Bone Grafting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vaibhav Gautam, Abhishek Vaish, and Raju Vaishya

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Silicone Implants in Orthopaedic Traumatology . . . . . . . . . . . . . Christian M. Lozano, S. Samundeeswari, and Saseendar Shanmugasundaram

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Primary Arthroplasty for Fractures of the Acetabulum Prashanth D’sa and Khitish Mohanty

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Primary Arthroplasty for Fractures of the Proximal Femur . . . . Prashanth D’sa and Khitish Mohanty

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Primary Arthroplasty for Fractures Around the Knee Prashanth D’sa and Khitish Mohanty

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Primary Arthroplasty for Proximal Humeral Fractures and Fracture Sequelae Following Implant Failure . . . . . . . . . . . . Hari K. Ankem and Srinath Kamineni

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Part VI

Other Implants Used in Orthopaedic Implantology . . . . . . .

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Titanium Elastic Nails in the Management of Fractures . . . . . . . Saseendar Shanmugasundaram, Smruti Ranjan Panda, S. Samundeeswari, and Debabrata Kumar

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Importance of Orthopaedic Screws . . . . . . . . . . . . . . . . . . . . . . . . Rajagopalan Iyer and S. Samundeeswari

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Role of K-wires in Orthopaedic Traumatology . . . . . . . . . . . . . . . Ananda Mandal and Gautam Gupta

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Tension Banding, Cerclage Wires and Cables in Management of Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. Rex and S. Vijaya Anand

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Contents

Implants Used for Periprosthetic Fractures . . . . . . . . . . . . . . . . . Sidhant Goyal, Gokulraj Dhanarajan, Mohamed Nazir Ashik, and Girish Gadekar

Part VII Metallurgy and Biomechanics in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

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Evolution and Principles of Metals and Alloys Used in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . Satish Mutha

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Biomechanics of Orthopaedic Implants Demystified Ananda Kisor Pal and Debadyuti Baksi

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Less Used Orthopaedic Implants . . . . . . . . . . . . . . . . . . . . . . . . . Srinivas B. S. Kambhampati, R. Senthilvelan, and Mounika N. S. Chodavarapu

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Volume 2 Part VIII Strategies in Choosing Orthopaedic Trauma Implants in Complex Cases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

39

40

41

Multidisciplinary Approach to Major Trauma: Changing Strategies and Priorities in Orthopaedic Implantology . . . . . . . . Peter Biberthaler and Saseendar Shanmugasundaram Orthopaedic Implant Fixation Strategies in Multiple Limb Injury Combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Alexander Burdach, Peter Biberthaler, and Saseendar Shanmugasundaram

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Orthopaedic Implant Fixation Strategies for Multiple Fractures in a Single Bone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kai Hoffeld, Peter Biberthaler, and Saseendar Shanmugasundaram

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Using Different Implant Combinations to Improve Fracture Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Olivia Mair, Peter Biberthaler, and Saseendar Shanmugasundaram

741

Part IX Infrastructure Necessary for Orthopaedic Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

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Importance of Orthopaedic Infrastructure and Ancillary Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Luis A. Bahamonde, Álvaro I. Zamorano, and Pierluca Zecchetto

751

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Contents

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43

Orthopaedic Tables and Their Evolution . . . . . . . . . . . . . . . . . . . Manas Saha

44

Intraoperative Imaging Techniques in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jose Ricardo Castro Obeso, S. Samundeeswari, and Saseendar Shanmugasundaram

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47

48

49

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How 3D CT Scans Are Revolutionizing Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gaur Gautam Kar

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Cutting Tools Used in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arindam Chatterjee and Gaur Gautam Kar

813

Role of Vacuum Suction Therapy in Orthopaedic Wound Closure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Álvaro I. Zamorano, Pierluca Zecchetto, and Luis A. Bahamonde

829

Computer Navigation and Robotics in Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. Aziz, K. Alva, and R. Pandey

841

Components of Infrastructure Necessary for a Successful Implantation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gaur Gautam Kar

849

Part X

Bone Healing and Removal of Implants . . . . . . . . . . . . . . . . .

867

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Bone Healing in the Presence of Orthopaedic Implants . . . . . . . . Siddhartha Gupta

869

51

Removal of Orthopaedic Implants . . . . . . . . . . . . . . . . . . . . . . . . D. D. Tanna and Srinivas B. S. Kambhampati

905

Part XI Why Orthopaedic Trauma Implantology Is in a State of Flux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

53

Impact of Changing Epidemiology on Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . David Torres, Guillermo Araujo-Espinoza, and Saseendar Shanmugasundaram Impact of Increased Life Expectancy on Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Christian M. Lozano, S. Samundeeswari, Guillermo AraujoEspinoza, and Saseendar Shanmugasundaram

929

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Contents

Impact of Increased Body Mass Index on Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Saseendar Shanmugasundaram, Atul Bandi, S. Samundeeswari, and Debabrata Kumar

965

Changing Fracture Geometry and Its Impact on Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diego Costa Astur and Davi Casadio

975

Understanding and Appreciating Fracture and Fixation Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chandan Pathak

989

57

Changing Fracture Classifications in the Age of Three-Dimensional Computed Tomography Imaging . . . . . . . . . 1011 Arjun Jain, S. Samundeeswari, Saseendar Shanmugasundaram, and Debabrata Kumar

58

Quest for Better Fracture Reduction in Orthopaedic Traumatology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1039 Sutanu Hazra

Part XII Changes in Attitudes to Soft Tissue and Their Effect on Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1061 59

Indirect Reduction Techniques in Primary Fracture Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1063 Debajyoti Bose and Arindam Chatterjee

60

Evolution of Entry Points in Nailing of Long Bone Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1077 Kalyan Kumar Guha

61

MIPPO Techniques and Bridge Plates . . . . . . . . . . . . . . . . . . . . . 1093 Nikhilesh Das

62

Role of Spanning Implants in Fracture Management Jaydip Mukhopadhyay

63

Low-Contact Plates in Orthopaedic Trauma Implantology . . . . . 1129 Biplab Kumar Dolui and Rajarshi Ghosh

Part XIII

. . . . . . . . . 1111

Upper Limb Orthopaedic Trauma Implantology . . . . . . . . . 1137

64

Implantology of Fractures of the Clavicle . . . . . . . . . . . . . . . . . . . 1139 M. Shantharam Shetty and Mohamed Faheem Kotekar

65

Acromioclavicular Dislocation: Current Perspective on Optimal Surgical Techniques and Implants . . . . . . . . . . . . . . . . . 1157 Gaurav Gupta

Contents

xxiii

66

Implantology of Scapula and Glenoid Fractures . . . . . . . . . . . . . 1173 Vivek Trikha and Saubhik Das

67

Implantology of Fractures of the Proximal Humerus . . . . . . . . . . 1201 Abheek Kar

68

Implantology of Fractures of the Shaft of Humerus . . . . . . . . . . . 1223 Ujjwal K. Debnath

69

Implantology of Fractures of the Distal Humerus Karthik Vishwanathan

70

Implantology of Fractures of the Radial Head and Neck . . . . . . . 1277 Christopher Jukes, Margo Dirckx, and Joideep Phadnis

71

Implantology of Olecranon and Coronoid Fractures . . . . . . . . . . 1299 Margo Dirckx, Christopher Jukes, and Joideep Phadnis

72

Implantology of Fractures of the Shaft of Radius and Ulna . . . . . 1317 Gaur Gautam Kar

73

Implantology of Distal Radius and Distal Ulna Fractures . . . . . . 1333 Ravi Ganesh Bharadwaj

74

Implantology of Fractures of the Carpal Bones . . . . . . . . . . . . . . 1359 Soumen Das De

75

Implantology of Metacarpal Fractures . . . . . . . . . . . . . . . . . . . . . 1373 Balaji Dhandapani and Abhijeet L. Wahegaonkar

76

Implantology of Phalangeal Fractures . . . . . . . . . . . . . . . . . . . . . 1387 Jose Ricardo Castro Obeso

77

Upper Limb Orthopaedic Trauma Implantology in a Nutshell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1407 Ravi Ganesh Bharadwaj

. . . . . . . . . . . . 1245

Volume 3 Part XIV

Lower Limb Orthopaedic Trauma Implantology . . . . . . . . . 1413

78

Implantology of Fractures of the Head of Femur . . . . . . . . . . . . . 1415 John Mukhopadhaya and Janki Sharan Bhadani

79

Implantology of Fractures of the Neck of Femur . . . . . . . . . . . . . 1421 John Mukhopadhaya and Janki Sharan Bhadani

80

Implantology of Intertrochanteric Fractures . . . . . . . . . . . . . . . . 1439 Wasudeo Gadegone and B. Shivshankar

81

Implantology of Subtrochanteric Fractures . . . . . . . . . . . . . . . . . 1459 B. Shivashankar and Wasudeo Gadegone

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Contents

82

Implantology of Fractures of the Shaft of Femur Including Segmental and Combination Fractures . . . . . . . . . . . . . . . . . . . . 1479 Saumitra Misra

83

Implantology of Fractures of the Distal Femur Vivek Trikha and Anupam Gupta

84

Implantology of Fractures of the Proximal Tibia . . . . . . . . . . . . . 1527 Karthik Vishwanathan and Sudipta Ghosh

85

Implantology of Fractures of the Shaft of the Tibia Including Segmental Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1563 Amrish Kumar Jha

86

Implantology of Distal Tibia Fractures with Pilon Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1591 Rajiv Chatterjee and Mainak Chandra

87

Implantology of Ankle Fractures . . . . . . . . . . . . . . . . . . . . . . . . . 1609 Abhijit Bandyopadhyay

88

Implantology of Fractures of the Foot Nilesh Makwana and Salam Ismael

89

Lower Limb Orthopaedic Trauma Implantology in a Nutshell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1647 Arindam Banerjee

Part XV

. . . . . . . . . . . . . . 1503

. . . . . . . . . . . . . . . . . . . . . 1625

Paediatric Orthopaedic Trauma Implantology . . . . . . . . . . . 1651

90

Principles and Overview of Paediatric Orthopaedic Trauma Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1653 Federico Canavese, Antonio Andreacchio, and Ashok Johari

91

Implantology of Paediatric Upper Limb Fractures . . . . . . . . . . . 1675 Antonio Andreacchio, Flavia Alberghina, Federico Canavese, and Ashok Johari

92

Implantology of Paediatric Lower Extremity Fractures . . . . . . . . 1697 Blake K. Montgomery and Steven L. Frick

93

Extended Applications of Trauma Implants to Prevent or Treat Fractures in Pathological Bone . . . . . . . . . . . . . . . . . . . . . . 1715 Ashok Johari, Antonio Andreacchio, Federico Canavese, and Mohit J. Jain

Contents

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Part XVI Orthopaedic Trauma Implantology in Pelvi-acetabular Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1729 94

General Instrumentation and Implantology for Pelvi-acetabular Reduction and Fixation . . . . . . . . . . . . . . . . . . . 1731 Sameer Aggarwal and Vishal Kumar

95

Screws in Pelvic-acetabular Fracture Fixation . . . . . . . . . . . . . . . 1753 Madhav Karunakar, Abhay Elhence, and Gaurav Saini

96

Plate Designs and Their Applications in Acetabular and Pelvic Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1767 Mehool R. Acharya and Walid A. ElNahal

97

External Fixation in Pelvi-acetabular Implantology . . . . . . . . . . . 1783 Abhay Elhence and Akshat Gupta

98

New Ideas and Innovations in Pelvi-acetabular Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1797 Ramesh Kumar Sen

Part XVII 99

The Implantology of Spinal Surgery . . . . . . . . . . . . . . . . . . 1807

Introduction and History of Spinal Implantology Chinmay Nath and Dinesh Kumar Jaiswal

. . . . . . . . . . . . 1809

. . . . . . . . . . . . . . . . . . . . . . . 1831

100

Biomechanics of the Cervical Spine Ujjwal K. Debnath

101

Biomechanics of the Thoracic Spine . . . . . . . . . . . . . . . . . . . . . . . 1853 Ahmad Hammad, Vijay Goel, and Alaaeldin A. Ahmad

102

Biomechanics of the Lumbar Spine . . . . . . . . . . . . . . . . . . . . . . . 1871 Abhijeet Ghoshal and Michael J. H. McCarthy

103

Bioengineering of Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . 1895 Christopher John Gerber, Anindya Basu, and Selvin Prabhakar Vijayan

104

Allied Devices and Their Influence on Spinal Implants . . . . . . . . 1915 Luis E. Nuñez Alvarado

105

Complications of Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . . 1935 Abhishek Ray

106

Recent Advances in Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . 1949 Abhishek Ray

107

Craniovertebral Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1977 Saumyajit Basu and Somashekar Doddabhadre Gowda

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Contents

108

Anterior Cervical Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . 1991 Saikat Sarkar

109

Posterior Cervical Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . 2013 Dinesh Kumar Jaiswal

110

Cervico-thoracic Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . . 2023 Gomatam Vijay Kumar

111

Posterior Thoracic Spinal Implants Chinmay Nath

112

Anterior Thoracic Spinal Implants . . . . . . . . . . . . . . . . . . . . . . . . 2075 Kiran Kumar Mukhopadhyay and Chinmay Nath

113

Lumbar and Lumbo-sacral Spinal Implants Chinmay Nath and Susmit Naskar

114

Sacral and Sacro-pelvic Implants . . . . . . . . . . . . . . . . . . . . . . . . . 2123 Saumyajit Basu and Somashekar Doddabhadre Gowda

. . . . . . . . . . . . . . . . . . . . . . . 2039

. . . . . . . . . . . . . . . . 2093

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2139

About the Editors

Arindam Banerjee has more than 35 years’ work experience in five countries. He is Consultant Orthopaedic Surgeon at Narayana Super-specialty and Multispecialty Hospitals, India, as well as Founder-Director of Medline Nursing Home. His special interests are traumatology (including Polytrauma and Implantology) and hip and knee arthroplasty. Dr. Banerjee currently holds the posts of Secretary General and President-Elect of World Orthopaedic Concern (WOC) International. Concomitantly, he is the secretary-general of the Indian chapter of WOC. He is an examiner of SICOT Diploma (World Congress of Orthopaedics) and chair of the Education Committee of SICOT, having been the former Chair of its Education Day Committee. He is member at Large of ARTOF (Association of Rational Treatment of Fractures) based in Munich, Germany. In the past, he has served as President, NAILS (National Association of Interlocking Surgeons) and AOTS (Association of Orthopaedic Trauma Surgeons). He is a former treasurer of the West Bengal Orthopaedic Association (WBOA) and has been the organising secretary or organising chairperson of several large academic conferences including the Silver Jubilee WBOACON, NAILSCON and Trauma Update, in Kolkata, India. He is a founder member of the West Bengal Arthroplasty Society and its former treasurer. He was selected Valedictorian of Vienna University in 1989, during his training. He was Senior IOS (UK) Fellow in 2008 (currently known as British India Orthopaedic Society) and Indo-Bavarian Travelling Fellow (2016) and guest lecturer at Munich Technical University. xxvii

xxviii

About the Editors

This book, Handbook of Orthopaedic Trauma Implantology, has been classified by Springer Nature as a MRW (Major Reference Work) and is the first book of its kind on the subject. Prof. Dr. Peter Biberthaler is Director and Chief of Trauma Surgery at the Klinikum rechts der Isar, Technical University of Munich (TUM). TUM is a level 1 trauma centre and deals with polytrauma and complex fractures and joint injuries. Dr. Biberthaler’s personal expertise includes fracture and replacement surgery of the hip, arthroscopic surgery and replacement surgery of the shoulder, as well as complex joint fractures affecting the shoulder, knee and ankle. He has performed over 9000 surgical procedures. He is the recipient of multiple awards including the Innovation Award of the German Association of Trauma Surgeons (2002), Otto Goetze Award of the Association of Bavarian Surgeons (2004), Education Award from US Shock Society (2005) and Herbert Lauterbach Award (2006), amongst others. He was President of the Association for the Rational Treatment of Fractures (ARTOF) from 2007 until 2016. He has published numerous articles in various journals and served as an editor for textbooks and improved various surgical techniques. Dr. Saseendar Shanmugasundaram is Professor of Orthopaedics and Clinical Lead of Arthroscopy and Sports Medicine at Sri Lakshmi Narayana Institute of Medical Sciences in Puducherry, India. He is also the founder of “CARE Sports Injury”, a dedicated centre for Arthroscopic Surgery and Rehabilitation. His areas of interest include orthopaedic traumatology and arthroscopy and sports surgery. Dr. Saseendar Shanmugasundaram is actively involved in clinical research and serves on the editorial board of various indexed orthopaedic journals – of note being his position as deputy editor of the Journal of Clinical Orthopaedics and Trauma published by Elsevier.

About the Editors

xxix

Dr. Saseendar Shanmugasundaram serves as an examiner for Orthopaedic Postgraduates. He currently holds the position of vice-chair of the Education Committee of SICOT (Société Internationale de Chirurgie Orthopédique et de Traumatologie) and is also examiner for the Diploma SICOT Examination. Furthermore, he occupies executive committee roles in prominent international and national orthopaedic organizations such as SICOT, WOC (World Orthopaedic Concern) and TNAS (Tamil Nadu Arthroscopy Society). He was awarded the Lester Lowe Award by SICOT, Belgium, underscoring his contributions to the field. He was the International Society of Orthopaedic Centres Travelling Fellow in 2012, APKASS-SLARD Travelling Fellow in 2018 and SKRF-BIOS Travelling Fellow in 2019. He is also the Valedictorian at JIPMER (Jawaharlal Institute of Postgraduate Medical Education and Research) in 2010.

Section Editors

Arindam Banerjee NH Narayana Superspeciality and Multispeciality Hospitals Howrah, India

Ravi Ganesh Bharadwaj Department of Orthopaedics Apollo Multispecialty Hospitals Kolkata, India

Peter Biberthaler Department of Orthopaedics Technical University of Munich Munich, Germany

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xxxii

Section Editors

Rajiv Chatterjee Department of Orthopaedics Manipal Hospital Kolkata, India

Ujjwal K. Debnath Department of Orthopaedics Jagannath Gupta Institute of Medical Sciences Kolkata, India

Sandip Ghosh Department of Orthopaedics R G Kar Medical College & Hospital, Kolkata Kolkata, India

Sidhant Goyal Department of Orthopaedics MGM Medical College & Hospital Aurangabad, India

Section Editors

xxxiii

Ashok Johari Children’s Orthopaedic Centre Mumbai, India

Srinivas B. S. Kambhampati Sri Dhaatri Orthopaedic, Maternity & Gynaecology Center Vijayawada, Andhra Pradesh, India

Gaur Gautam Kar Department of Orthopaedics MGM Medical College Kishanganj, Bihar, India

xxxiv

Section Editors

Muthur Ajith Kumar Department of Orthopaedics and Trauma, Tejasvini Hospital Mangalore, Karnataka, India

Debabrata Kumar Department of Trauma and Orthopaedics Buckinghamshire NHS Trust Buckinghamshire, England

Christian M. Lozano Department of Orthopaedics Clinica Anglo Americana Lima, Peru

Section Editors

xxxv

Saumitra Misra Department of Orthopaedics Manipal Hospital Kolkata, India

Chinmay Nath Apollo Multispecialty Hospital Kolkata, India

Ananda Kisor Pal Department of Orthopaedics and Traumatology Jalpaiguri Government Medical College and Hospitals Jalpaiguri, West Bengal, India

xxxvi

Section Editors

S. Samundeeswari Department of Orthopaedics Sri Lakshmi Narayana Institute of Medical Sciences Puducherry, India

Ramesh Kumar Sen Institute of Orthopaedic Surgery Max Hospital Mohali, Chandigarh Tricity, India

Saseendar Shanmugasundaram Department of Orthopaedics Sri Lakshmi Narayana Institute of Medical Sciences Puducherry, India

M. Shantharam Shetty NITTE University, Tejasvini Hospital Mangalore, Karnataka, India

Section Editors

xxxvii

David Torres Department of Orthopaedics Clinica Anglo Americana Lima, Peru

Álvaro I. Zamorano Department of Orthopaedics and Traumatology University of Chile Clinical Hospital and Mutual de Seguridad Clinical Hospital Estación Central, Región Metropolitana, Chile

Contributors

Mehool R. Acharya Pelvic and Acetabular Reconstruction Unit, Southmead Hospital, Bristol, UK Sameer Aggarwal Department of Orthopedic Surgery, PGIMER Chandigarh, Chandigarh, India Alaaeldin A. Ahmad Pediatric orthopedic, Annajah Medical School, Nablus, Palestine Flavia Alberghina Regina Margherita, Children’s Hospital, Turin, Italy K. Alva Department of Trauma and Orthopaedic Surgery, University Hospitals of Leicester, Leicester, UK S. Vijaya Anand Rex Ortho Hospital, Coimbatore, India Antonio Andreacchio Pediatric Orthopedic Surgery Department, Children’s Hospital “Vittore Buzzi”, Milan, Italy Hari K. Ankem Department of Orthopaedic Surgery, University of Louisville, Louisville, KY, USA Guillermo Araujo-Espinoza Clinica Anglo Americana, Lima, Peru Mohamed Nazir Ashik Department of Orthopaedics, ESIC Medical College & PGIMSR, Chennai, India Diego Costa Astur Orthopaedic Surgeon from Sports and Traumatology Division from Orthopedic and Traumatology Department of Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil S. Aziz Department of Trauma and Orthopaedic Surgery, University Hospitals of Leicester, Leicester, UK Vaibhav Bagaria Department of Orthopaedics, Sir HN Reliance Foundation Hospital, Mumbai, India

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Contributors

Luis A. Bahamonde Orthopaedic and Traumatology Department, University of Chile Medical School, Santiago, Chile Lower Extremities Trauma Unit, Orthopaedic and Traumatology Service, Mutual de Seguridad Clinical Hospital, Santiago, Chile Orthopaedic Surgery, University of Chile Clinical Hospital, Santiago, Chile Debadyuti Baksi Department of Orthopaedics, Sri Ramakrishna institute of Medical Sciences, Durgapur, India Atul Bandi King Hamad University Hospital, Al Sayh, Bahrain Abhijit Bandyopadhyay Orthopaedic Department, Woodland Multispecialty Hospital, Kolkata, India Arindam Banerjee Orthopaedic Surgery, NH Narayana Superspeciality and Multispeciality Hospitals, Howrah, West Bengal, India Mohit Bansal Kings College Hospital, London, UK Anindya Basu Institute of Neurosciences Kolkata, Kolkata, India Saumyajit Basu Kothari Medical Centre, Kolkata, West Bengal, India Subrata Basu Department of Orthopaedics, Howrah Orthopedic Hospital, Howrah, India Janki Sharan Bhadani Paras HMRI Hospital, Patna, India Ravi Ganesh Bharadwaj Apollo Multispecialty Hospitals, Kolkata, India Department of Orthopaedics, Apollo Gleneagles Hospitals, Kolkata, India Shyamasunder N. Bhat Department of Orthopaedics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Udupi District, Karnataka, India Chandrachur Bhattacharyya Ramkrishna Mission Seva Pratisthan Hospital, Kolkata, India Peter Biberthaler Technical University of Munich, Munich, Germany Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany Amit Bishnoi Leicester Hospitals, Leicester, UK Debajyoti Bose Sonoscan Hospital, Malda, India Alexander Burdach Technical University of Munich, Munich, Germany Zack P. Burrow Department of Orthopedic Surgery and Rehabilitation, University of Oklahoma College of Medicine, Oklahoma City, OK, USA Emrah Caliskan Departments of Orthopaedics and Traumatology, Koc University Hospital, Istanbul, Turkey

Contributors

xli

Federico Canavese Pediatric Orthopedic Surgery Department, Lille University Center, Jeanne de Flandre Hospital, Lille, France Faculty of Medicine, Nord-de-France Lille University, Lille, France Davi Casadio Orthopaedic Surgeon from Sports and Traumatology Division from Orthopedic and Traumatology Department of Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil Jose Ricardo Castro Obeso Hand and Upper Limb Surgery, Clinica Anglo Americana, Lima, Peru Mainak Chandra R G Kar Medical College and Hospital, Kolkata, India Arindam Chatterjee Orthopaedics, IPGMER and SSKM HOSPITAL, Kolkata, West Bengal, India Rajiv Chatterjee Manipal Hospital Kolkata, Kolkata, India Ishani Milind Chaudhary Institute- Center For Ilizarov Techniques, Akola, India Milind Madhav Chaudhary Institute- Center For Ilizarov Techniques, Akola, India Mounika N. S. Chodavarapu Siddhartha Medical College, Vijayawada, India Prashanth D’sa Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK Nikhilesh Das Peerless Hospital and B.K. Roy Research Center, Kolkata, West Bengal, India Saubhik Das Orthopaedics, Rajendra Institute of Medical Sciences (RIMS), Ranchi, Jharkhand, India Shamal Das De University Orthopedics, Hand & Reconstructive Microsurgery cluster, National university Hospital, Singapore, Singapore Soumen Das De Department of Hand & Reconstructive Microsurgery, National University Health System, Singapore, Singapore Shiuli Dasgupta KPC Medical College and Hospital, Kolkata, West Bengal, India Ujjwal K. Debnath Jagannath Gupta Institute of Medical Sciences (JIMSH), Kolkata, West Bengal, India AMRI Hospital, Kolkata, West Bengal, India Gokulraj Dhanarajan Department of Orthopaedics, Fortis Hospitals, Chennai, India Balaji Dhandapani Department of Upper Limb, Hand and Microvascular Reconstructive Surgery, Sahyadri Hospitals, Jehangir Hospital, Sancheti Institute for Orthopedics and Rehabilitation, Pune, India

xlii

Contributors

Margo Dirckx Shoulder & Elbow Unit, Brighton and Sussex University Hospitals, Brighton, UK Somashekar Doddabhadre Gowda Specialist Hospital, Bengaluru, Karnataka, India Biplab Kumar Dolui Desun Hospital, Kolkata, India Rodrigo Donoso Orthopedic Surgery, Pontifical Catholic University of Chile, Santiago, Chile Abhay Elhence AIIMS Jodhpur, Jodhpur, Rajasthan, India Walid A. ElNahal Pelvic and Acetabular Reconstruction Unit, Southmead Hospital, Bristol, UK Trauma and Orthopaedic Department, Cairo University Hospitals, Cairo, Egypt Bulent Erol Departments of Orthopaedics and Traumatology, Marmara University Pendik Research and Training Hospital, Istanbul, Turkey Steven L. Frick Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA, USA Piyush Gadegone Gadegone Orthopaedic and Trauma Care Hospital, Chandrapur, India Wasudeo Gadegone Gadegone Orthopaedic and Trauma Care Hospital, Chandrapur, India Girish Gadekar Department of Orthopaedics, MGM Medical College & Hospital, Aurangabad, Maharashtra, India Vaibhav Gautam Department of Orthopaedics and Joint Replacement Surgery, Indraprastha Apollo Hospitals, New Delhi, Delhi, India Christopher John Gerber Institute of Neurosciences Kolkata, Kolkata, India Rajarshi Ghosh Kothari Medical Centre, Kolkata, West Bengal, India Sudipta Ghosh Woodlands Multispeciality Hospital Limited, Kolkata, India Abhijeet Ghoshal University Hospital of Wales, Cardiff, UK Vijay Goel Engineering Center for Orthopedic Research Excellence (E-CORE), University of Toledo, Toledo, OH, USA Sidhant Goyal Department of Orthopaedics, MGM Medical College & Hospital, Aurangabad, Maharashtra, India Kalyan Kumar Guha Woodlands Multispeciality Hospital Limited, Kolkata, India Akshat Gupta AIIMS, Jodhpur, India Anupam Gupta Orthopaedics, AIIMS, New Delhi, Delhi, India

Contributors

xliii

Gaurav Gupta Fortis Hospital, Kolkata, India Gautam Gupta Orthopedic, Techno India DAMA Hospital, Kolkata, West Bengal, India Siddhartha Gupta Shree Jain Hospital and Research Center, Kolkata, West Bengal, India Ahmad Hammad American University of Beirut, Beirut, Lebanon Sutanu Hazra AMRI Mukundapur, Medica Superspecialty Hospital, Kolkata, India Kai Hoffeld Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany Sebastián Irarrázaval Pontifical Catholic University of Chile, Santiago, Chile Salam Ismael Trauma and Orthopaedic Specialist Trainee, The Robert Jones and Agnes Hunt Hospital Foundation Trust, Oswestry, Shropshire, UK Karthikeyan. P. Iyengar Southport and Ormskirk NHS Trust, Southport, UK Rajagopalan Iyer Department of Orthopaedics, Pondicherry Institute of Medical Sciences, Kalapet, India Arjun Jain Sri Aurobindo Medical College and PG Institute, Indore, India Mohit J. Jain Clinical Fellow in Orthopedic Sports Medicine, Jefferson Health NorthEast, Philadelphia, PA, USA Dinesh Kumar Jaiswal ILS Hospital, Kolkata, West Bengal, India Amrish Kumar Jha Niramaya: Jha’s Superspeciality Centre for Orthopaedics, Dumdum, Kolkata, West Bengal, India Ashok Johari Children’s Orthopaedic Centre, Mumbai, MH, India Christopher Jukes Shoulder & Elbow Unit, Brighton and Sussex University Hospitals, Brighton, UK Srinivas B. S. Kambhampati Sri Dhaatri Orthopaedic, Maternity & Gynaecology Center, Vijayawada, India Srinath Kamineni Department of Orthopaedic Surgery (Elbow Shoulder Research Center), University of Kentucky, Lexington, KY, USA Abheek Kar Shoulder Clinic, Apollo Multispeciality Hospitals, Kolkata, India Gaur Gautam Kar Department of Orthopaedics, MGM Medical College and LSK Hospital, Kishanganj, Bihar, India Department of Orthopaedics, Apollo Gleneagles Hospitals, Kolkata, West Bengal, India

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Contributors

Madhav Karunakar Department of Orthopaedic Surgery, Carolinas Medical Center, Atrium Musculoskeletal Institute, Charlotte, NC, USA Mohamed Faheem Kotekar Department of Orthopaedics, Tejasvini Hospital, Mangalore, Karnataka, India Debabrata Kumar International Training Fellow (Hip & Knee)-Department of Trauma and Orthopaedics, Russells Hall Hospital, Dudley, West Midlands, England Muthur Ajith Kumar Department of Orthopaedics and Trauma, Tejasvini Hospital, Mangalore, Karnataka, India Vishal Kumar Associate Professor, Department of Orthopaedics, Post-Graduate Institute of Medical Education and Research, Chandigarh, India Christian M. Lozano Department of Orthopaedics, Clinica Anglo Americana, Lima, Peru Olivia Mair Department of Trauma Surgery, Klinikum rechts der Isar, Technical University Munich, Munich, Germany Nilesh Makwana Consultant Trauma and Orthopaedic Surgeon, The Robert Jones and Agnes Hunt Hospital Foundation Trust, Oswestry, Shropshire, UK Ananda Mandal CK Birla Hospital, Calcutta Medical Research Institute, Kolkata, West Bengal, India Michael J. H. McCarthy University Hospital of Wales, Cardiff, UK Lara Elizabeth McMillan Southport and Ormskirk NHS Trust, Southport, UK Saumitra Misra Manipal Hospital, Kolkata, India Khitish Mohanty Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK Blake K. Montgomery Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA, USA John Mukhopadhaya Paras HMRI Hospital, Patna, India Jaydip Mukhopadhyay Binayak Multispeciality Hospital, Kolkata, India Kiran Kumar Mukhopadhyay N R S Medical College & Hospital, Kolkata, India Satish Mutha Hinduja Healthcare Services, Mumbai, India Arjun Naik Kings College Hospital, London, UK Prashanth Naik Aintree University Hospital, Liverpool, UK Badri Narayan Limb Reconstruction Service, Liverpool University Hospitals, Liverpool, UK Susmit Naskar Narayana superspeciality hospital, Howrah, India

Contributors

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Chinmay Nath AMRI Hospital, Kolkata, West Bengal, India Luis E. Nuñez Alvarado Pediatric Orthopedic Surgery, National Institute of Child Health – San Borja, Lima, Peru Department of orthopedics and traumatology, Clinica Anglo Americana, Lima, Peru Shailesh Pai Tejasvini Hospital, Mangalore, India Ananda Kisor Pal Department of Orthopedics, Jalpaiguri Government Medical College and Hospitals, Jalpaiguri, India Department of Orthopedics, IPGMER and SSKM Medical College, Kolkata, India The Centre of Excellence, Kolkata, India Smruti Ranjan Panda Mercy Hospital, Kolkata, West Bengal, India R. Pandey Department of Trauma and Orthopaedic Surgery, University Hospitals of Leicester, Leicester, UK Chandan Pathak Howrah Orthopaedic Hospital, Eastern Railway, Howrah, West Bengal, India Joideep Phadnis Shoulder & Elbow Unit, Brighton and Sussex University Hospitals, Brighton, UK Vasantha Kumar Ramsingh Pilgrim Hospital, Boston, UK Nipun Rana Department of Orthopedics, Sir Ganga Ram Hospital, New Delhi, India Abhishek Ray The Mission Hospital, Durgapur, West Bengal, India C. Rex Department of Orthopedics, Rex Ortho Hospital, Coimbatore, India Omkar Sadigale Department of Orthopaedics, Sir HN Reliance Foundation Hospital, Mumbai, India Manas Saha Anandalok Hospital, Kolkata, West Bengal, India Gaurav Saini Institute of Orthopaedic Surgery, Max Hospital Mohali, Mohali, Punjab, India S. Samundeeswari Department of Orthopaedics, Sri Lakshmi Naryana Institute of Medical Sciences, Puducherry, India Saikat Sarkar Manipal Hospitals, Columbia Asia Hospital, Kolkata, West Bengal, India Dipankar Sen Department of Orthopaedics, IQ City Medical College Hospital, Durgapur, India Ramesh Kumar Sen Institute of Orthopaedic Surgery, Max Hospital, Mohali, India

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R. Senthilvelan MIOT, Chennai, India Saseendar Shanmugasundaram Department of Orthopaedics, Sri Lakshmi Naryana Institute of Medical Sciences, Puducherry, India Amit Sharma Spine Surgery, Saifee Hospital, Mumbai, India M. Shantharam Shetty NITTE University, Tejasvini Hospital, Mangalore, Karnataka, India B. Shivashankar Iyer Orthopaedic Centre, Solapur, Maharashtra, India Sriram Srinivasan Royal Stoke Hospital, Stoke-on-Trent, UK D. D. Tanna Jaslok Hospital and Research Centre, H. N. Reliance Hospital, Saifee Hospital, Bhatia Hospital, Mumbai, Maharashtra, India Rishi Thakral Department of Orthopedic Surgery and Rehabilitation, University of Oklahoma College of Medicine, Oklahoma City, OK, USA David Torres Clinica Anglo Americana, Lima, Peru Vivek Trikha JPNATC, AIIMS, New Delhi, India Abhishek Vaish Department of Orthopaedics and Joint Replacement Surgery, Indraprastha Apollo Hospitals, New Delhi, Delhi, India Raju Vaishya Department of Orthopaedics and Joint Replacement Surgery, Indraprastha Apollo Hospitals, New Delhi, Delhi, India Gomatam Vijay Kumar Neurosurgery, Fortis Hospital, Kolkata, West Bengal, India Selvin Prabhakar Vijayan Institute of Neurosciences Kolkata, Kolkata, India Karthik Vishwanathan Department of Orthopaedics, Parul Institute of Medical Sciences and Research, Parul University, Vadodara, India Abhijeet L. Wahegaonkar Department of Upper Limb, Hand and Microvascular Reconstructive Surgery, Sahyadri Hospitals, Jehangir Hospital, Sancheti Institute for Orthopedics and Rehabilitation, Pune, India K. Yogesh Tejasvini Hospital, Mangalore, Karnataka, India Álvaro I. Zamorano Lower Extremities Trauma Unit, Orthopaedic and Traumatology Service, Mutual de Seguridad Clinical Hospital, Santiago, Chile Orthopaedic Surgery, University of Chile Clinical Hospital, Santiago, Chile Pierluca Zecchetto Lower Extremities Trauma Unit, Orthopaedic and Traumatology Service, Mutual de Seguridad Clinical Hospital, Santiago, Chile Orthopaedic Surgery, University of Chile Clinical Hospital, Santiago, Chile

Part I General Introduction to Orthopaedic Trauma Implantology

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The Science, Art, and Commerce of Orthopaedic Trauma Implantology: How to Use This Book Arindam Banerjee, Saseendar Shanmugasundaram, and Shiuli Dasgupta

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Has Changed in Orthopaedic Traumatology over the Years? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Why Are There So Many Different Kinds of Trauma Implants? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . What Are Orthopaedic Trauma Implants? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Factors Which Influence Implantology and Choice and Evolutions of Implants . . . . . . . . . . . . . . . Rationale of Trauma Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective of a Trauma Implant and How It Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Management of Fractures Without Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Management of Fractures with Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reduce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Retain (with Implants) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bone Augmentation Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Implantology has evolved a lot over the decades from being an inexact science to offering the very latest in biological and patient-specific fixation options. In the 1960s, the AO-ASIF laid the foundation stone of modern orthopaedic trauma implant. The group brought about precision, standardization in the implant structure, and predictability in the surgical technique, converting an approximate discipline into an exact science. In this book, we coin the word “Orthopaedic A. Banerjee (*) Orthopaedic Surgery, NH Narayana Superspeciality and Multispeciality Hospitals, Howrah, West Bengal, India e-mail: [email protected] S. Shanmugasundaram Department of Orthopaedics, Sri Lakshmi Naryana Institute of Medical Sciences, Puducherry, India S. Dasgupta KPC Medical College and Hospital, Kolkata, West Bengal, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_1

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Implantology”, and discuss in detail the evolution and principles of use of various implants region wise. We hope that this book will inspire the study of orthopaedic implantology as a separate subspecialty. We have delved into the reason orthopaedic implants have changed so much over the decades, the rationale behind the use of trauma implants, and the various types of implants (plates and screws, rigid nails, elastic nails, external fixators, cannulated screws, Kirchner wires, stainless steel wires and cables, prostheses, bone augmentation devices, etc.) that have dominated orthopaedic implant surgeries over the years. Keywords

Orthopaedic implantology · Orthopaedic implants · Plates · Nails · Screws · External fixators

Introduction Implants have been used to fix fractures for over a hundred years. However, historically, implantology was an inexact science dependent heavily on the preferences of individual surgeons and local manufacturers. Many surgeons designed an implant or two (often in his own name) which was often only used by him and perhaps a few others. At that point of time, the types and availability of implants were completely arbitrary and haphazard. In the 1960s, four famous Swiss surgeons got together and formed the AO-ASIF group. The AO-ASIF completely revolutionized this attitude. Bringing in industriallevel precision to the manufacture of implants and orthopaedic equipments, it brought standardization to the table. Predictability in technique and results became commonplace. The AO-ASIF group therefore converted an approximate discipline into an exact science [1]. Since then the journey became more systematic. In many cases these improvements and innovations were logical like putting brick upon brick. At other times, there were impractical ideas which clinicians championed long before their time had come. Biomechanical principles were often ill-understood or material sciences and surgical skills lagged behind. Some ideas could not withstand the rigors of clinical demands. In vitro and in vivo testing is different in the life sciences as opposed to physical sciences. Wrong turns and dead ends were numerous. But what is baffling is the lack of documentation of this path of human progress except in the occasional journal article or conference presentation. Orthopaedic academic literature has by and large ignored this journey. The current book attempts to fill this lacuna. It will provide an overview of the story as it unfolds trying to show a degree of coherence in the advancements of fracture fixation methodology. This story will not be told from the point of view of a historian but from the scientific scholarship of a traumatologist. In this book, we coin the word implantology which has hitherto only been used for dental implants [2]. Yet orthopaedic traumatologists use implants much more

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frequently than dental surgeons. We will also attempt to study this subject as a separate subspecialty, a subset of orthopaedic traumatology. In this book, we will however not document other subsets of implantology such as arthroplasty implantology or tumour implantology where medical literature and documentation already exists.

What Has Changed in Orthopaedic Traumatology over the Years? Our* generation of orthopaedic traumatologists have been associated with implantology for more than three decades. The subject has undergone a sea of change in front of our eyes. Practically none of the operations which were taught to do in our training period are done today. The few that have survived have been modified beyond recognition. Almost all aspects have changed. We are enumerating a few so that the degree of change involved can be appreciated: • • • • • • • • •

Surgical incisions Surgical exposures of fractures and protection of neurovascular structures The handling of soft tissues The variety of orthopaedic general instruments available Specialized orthopaedic equipment availability The purpose of the operation The surgical steps and the goal of surgery The radiology involved such as a C-arm or 3D CT scans The furniture required like orthopaedic traction tables, radiolucent hand tables, etc. • Material sciences – metal alloys and polyethylene, flexible reamers, etc. • Anaesthetic techniques with regional blocks, antibiotics regimes, and intensive care support • MIPPO techniques, minimally invasive surgery, indirect reduction of fractures, and entry points for nailing And finally: • Orthopaedic implants *The generation of the senior (first) author of this chapter Implants have changed the most. They attracted commercial enterprises into traumatology, and these enterprises themselves fuelled the progress of traumatology by continuous investment into material sciences, surgical techniques and courses as well as design R&D. However, these courses and workshops championed by various commercial firms have taught traumatologists their techniques, familiarized them with their implants so that their products could be sold. All these have been done in the name of quality control.

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Quality control is important in surgery. In the early days of total hip surgery, Sir John Charnley would not allow any surgeon to use his arthroplasty implants until (s) he underwent a suitable training course successfully. This led to regulation of standards in the early days of arthroplasty. However, if regulation is too rigid it can strangle progress and stifle innovation leading to stagnation. But if no regulation and oversight is exercised, it may allow commercial enterprises to seize the initiative. Obviously there has to be a control mechanism to prevent the growth of substandard implants and prosthesis but it must not be in the hands of commercial organizations. It should be under the charge of academic authorities [3].

Why Are There So Many Different Kinds of Trauma Implants? In orthopaedic conferences one may frequently hear a debate such as: Nailing versus plating – which is better for a specific fracture? This is usually a generic debate. What is not acknowledged is that for that specific fracture there might be three types of nails and four different plates. So, which one is better? Nail no. 1 or plate no. 4? It is very likely the number of cases done of each will not throw up statistically significant results leaving no one any wiser after the discussion is over. But it does invite the next question – why are there so many types of nails and plates for the same body region? Is it the inventiveness of the surgeon or the need to make changes in the original prototype to avoid patency laws? Or is it our experience with implant failure that we begin to appreciate the subtle nuances of fractures geometry? The type of operation of a particular fracture is often guided by the fracture classification. Historically, fracture classifications were haphazard. Again, it was often in the name of a specific surgeon and only used by his colleagues and acquaintances. Here the AO-ASIF again made a significant contribution. The AO group tried to bring all fracture classifications under one system. This allowed us to catalogue different fracture types under one system so that it became possible to compare different treatment modalities for the same or similar fractures and compare their outcomes [4]. Today, however, the AO classification of all fractures is under threat from subsequent developments and may need further and significant modifications. Traditionally all fracture classifications have been based on X-ray films (including the AO). In time, traumatologists became conscious that a fracture is a 3D entity and cannot be appreciated in its entirety using a 2D investigation such as an X-ray plate. 3D CTs have changed our understanding of fracture geometry. The column and pillar concept of fractures is gaining ground gradually. With time it is possible that all classifications will be challenged and with it the treatment modality as well as implantology may change [5]. Apart from fracture geometry, there are other important factors which have hitherto been ignored. They too may have bearing on future classifications and fixations. A few are enumerated below:

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Comorbidities influence treatment outcomes significantly. Surgical physiology is an equal partner of fracture geometry [6]. Different injury combinations in the same person can influence treatment and outcomes. This is another under-researched area of traumatology. A fracture of the femur and tibia on the contralateral or ipsilateral limb may have an influence on the implantology used and the timing of surgery. If we add an upper limb fracture or fractures of the axial skeleton to the equation, the approach to treatment may become more complex. Another factor which would influence implantology is the presence of multiple fractures within the same bone. A lot of discussion has been generated between usage of a single implant versus usage of multiple implants. The scope of this book is to pioneer the science of orthopaedic implantology. It will address the following issues about different implants: • • • •

How did this particular implant evolve – history and geography? Why did this particular implant evolve – what was the challenge it faced? Did it adequately solve the challenge? What issues were still unresolved? How did other sciences such as material sciences help develop this particular implant? • Did this implant survive the test of time? • How and why did it succeed and how and why did it fail? Biomechanics of the implant and operation. • What is the possible future of this particular implant or implant group? This book is primarily divided into two parts – general and regional. The general chapters deal with the core issues and different fracture fixation philosophies. The regional section deals with actual implants as used in limbs, spine, and pelvis. There is also a section which deals with paediatrics and another which deals with bone grafts. It will serve as a handbook for anyone who needs to brush up or reinforce his/her knowledge before operating. While the target audience remains orthopaedic trauma surgeons, we feel that it will be an important reference book for paramedics, physiotherapists, orthopaedic nurses, scientists as well as medical students of traumatology. We have therefore kept our approach to the simple. This chapter only deals with the basics of implantology. Details are incorporated in the relevant sections and subsections.

What Are Orthopaedic Trauma Implants? An orthopaedic trauma implant is a medical device manufactured to support a damaged bone or joint [7]. They are usually made from fabricated stainless steel and titanium alloys for strength with occasional plastic coating (such as polyethylene). The purpose of the implant is to stabilize movements at the fracture site and allow them to heal in a position which is closest to the pre-injury status. It acts as

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scaffolding to facilitate fracture union and consolidation. The characteristics of an ideal implant would be: • • • • • • • • • • • • •

Sufficient strength to neutralize the deforming forces acting on the fracture site Shape has to be compatible with the bone to be fixed Biomechanically stable and not prone to breakage Easy to insert for the surgeon Learning curve of the technique should not be steep The operation should not be dangerous to life or to a body part Easy to remove when necessary MRI compatible if possible Able to avoid damage to key neurovascular and locomotor units of the bone and muscles Thickness and profile should allow skin closure without tightness Easy to anchor to bone with holding devices such as screws Chemically inert and biocompatible Inexpensive if possible

In addition, the ideal implant material should also have the following characteristics [8]: • • • •

High fatigue resistance Low elastic modulus Absolutely corrosion proof Good wear resistance

Factors Which Influence Implantology and Choice and Evolutions of Implants There are many different types of orthopaedic implants. Not all of are used in trauma surgery. Non-trauma-related orthopaedic implants are used in: 1. Arthroplasty 2. Musculoskeletal tumour surgery 3. Implants to augment soft tissue surgery during arthroscopy, etc. This book will only deal with implants used during trauma. Occasionally implants used for non-trauma have extended indications for usage in trauma. We will include those. There are 208 bones in the human body almost all of them different from each other. A single episode of trauma can break one or several bones (depending on the energy of the injury). Some of these fractures may heal automatically. Many do not require or need fixation. The fracture pattern or fracture geometry [4] as it is called is

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unique to every injury and therefore needs different fixation implants. The fracture geometry and other factors enumerated below dictate the implant choice. Some of the other factors are: Shape of bones – most of them are irregular geometrically. This irregularity is three dimensional. The shape of the implant therefore may need to be irregular. Side – usually bones of the left or right are mirror images of each other. But because the shape of the bone is irregular, implants of the left side may not fit the right side and vice versa. Some implants such as rectangular plates or nails are straight in the sagittal plane (such as a K-nail or standard tibial nail) and fit both the left and right sides. It is important to understand that the more sophisticated an implant is, the more likely it will fit only one side of the body. Size (due to gender variations) – frequently females require smaller implant sizes. Therefore, manufacturers must provide a comprehensive range for the operating surgeon. Size (due to racial characteristics) – some races are bigger or smaller than others. While designing the PFN, it was necessary to make special sizes for Asian patients known as the PFNA2. Age – adult bones change with age. Patients above 40 years may have bone fragility or joint degeneration. As osteoporosis and the human life span have been rising globally, implants have had to be redesigned keeping this factor in mind. Fragility fractures spawned an entire new batch of locking plates with locking screws. Age – children’s bones have growth centres which gradually coalesce and morph into adult bones. Implants may damage active growth centres causing subsequent deformity. Therefore, design of implants in children may have to be different from adults. It is important to realize that children also are not a homogenous group of patients and may be of different builds. In fact, the current epidemic childhood obesity is changing the shape of children and their implant requirements. The shape of the bone and the growth centres are also different at different ages during childhood leading requirement of different varieties of implant at different stages of growth. With the rise of global childhood obesity, children often need adult size implants though the design might need to be special as damage to the growing part of the bone has to be avoided. It is important to realize that children are not young adults. They are physiologically and anatomically different [9]. Pathological bone (congenital or environmental) – some bones do not have normal anatomy or physiology. The consistency of bone may interfere with implant fixation and special design characteristics may have to be used. Tumours might require a completely different set of implants such as nails, prosthesis, or cement as opposed to standard plate fixation. Anatomical variations are normal in bone and design may have to accommodate these variations. For this either custom-build implants might be required in the occasional patient.

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Rationale of Trauma Implants An implant used during trauma is fundamentally different from the other subgroups of implants. Bone is living tissue. The human body has an inherent capacity to deal with musculoskeletal trauma. We carry a mechanism to repair and regenerate injured musculoskeletal tissue. Fracture union usually happens in most bones if the internal environment is favourable known as homeostasis [10]. Union usually occurs in undisplaced or minimally displaced fractures without much trouble as the nutrition to the bone is rarely disrupted. The exception is an intracapsular fracture where the tamponade effect of the hemarthrosis may cause nutritional disruption and subsequent avascular necrosis [11]. In displaced fractures the attempt at repair is strong. But the mechanism to restore the original anatomy is weak (apart from the role of gravity-induced traction in certain humeral fractures). This can lead to malunion. The muscles attached to a bone have specific functions which are linked to the functional anatomy of the bone. When the bone is deformed after a malunion, muscles and adjacent joints cannot act optimally. The best we can hope for is suboptimal muscular function and less than normal range of movements in adjacent joints. In the past, human beings were less demanding and more willing to accept imperfection. Nowadays, however, they often aspire to be restored to their pre-injury state of activity and performance as soon and as much as possible. This is one of the driving forces behind the development of a new generation of implants and operations. The objective of these implants is to prevent malunion by restoring anatomy and prevent stiffness by restoring physiology. Trauma implants are fundamentally different from the other implants used in orthopaedic subspecialties. Implants of all other subgroups of orthopaedics other than trauma are mostly replacement implants (prostheses). Prosthesis do not help with bone repair and is therefore designed to last a lifetime. In traumatology, however, the implant needs to last until the fracture unites and consolidates and until physiology is restored. Most fractures usually unite within a few months. Consolidation of the fracture usually occurs within a year or 18 months. It therefore follows that it should be possible to remove all trauma implants within 2 years of fixation. At 2 years, the trauma implant should make itself redundant by causing union and consolidation of the fracture. While we may not choose implant removal as an option in every single patient (as we are concerned that important adjacent neurovascular structures may be damaged during a second surgery at the same site), there should be no contraindication from the point of view of healing. Similarly, it is perfectly acceptable in principle to have a biodegradable trauma implant which is absorbed by the body after 2 years similar in principle to using a self-absorbing suture such as Vicryl [12]. The role of the trauma implant is similar to a nurse maid who holds the hand of a child to cross the road. By “crossing the road” we mean the path of repair and regeneration. The support of the implant is only to help and guide the process so that the outcome is satisfactory and optimum and functionality as close to the pre-injury state is achieved.

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The tools of an orthopaedic surgeon are remarkable, similar to a carpenter’s equipment. Nevertheless, there is a major difference which sets the two disciplines apart. An imperfectly fixed bone can go on to heal with time, restoring near perfection of function. A chair or table if built imperfectly will deteriorate with time. Consequently, an orthopaedic surgeon can theoretically get away with less exactness than a carpenter! While this concept might seem like a joke, it is not. The principles of carpentry on living and dead tissues are different.

Objective of a Trauma Implant and How It Works Musculoskeletal tissue is present all over the body. The purpose of any musculoskeletal unit in the body is movement. It comprises of bones, muscles, ligaments, tendons, and joints. The format of mobility is explained in the following line diagram (Fig. 1). The different parts of intact bone have adequate strength to resist the pull of a muscle and move together. They occasionally move relative to each other such as the radius encircling the ulna during pronation/supination. All movements take place at the joint which is a purpose-built structure to allow movement (Fig. 2). Fig. 1 Illustration of a unit of the musculoskeletal system consisting of the musculotendinous unit with its proximal and distal attachments, the joint and the bone. Most interventions in orthopaedic traumatology revolve around restoring this concept of the musculoskeletal system

Fig. 2 Illustration of the rotation of the radius around the ulna in (a) supination and (b) pronation

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There are 640 named skeletal muscles in the human body. Every muscle has origin(s) and insertion(s). The muscle is normally in a state of relaxation at rest but contracts when it is used. It has fibres running in multiple directions depending on its function. These muscles fibres often merge into a common tendon which has fibres running purposefully in a single direction. The tendinous insertions then merge into the periosteum for a good grip of the bone. This anatomical continuity allows the muscle to act on the part of the bone via the tendon. Multiple tendons pull different parts of the same bone in different directions (as they are inserted in the different surfaces and planes of a bone three dimensionally) resulting in diverse types of movement at the adjacent joints such as flexion, extension, supination, etc. This process acts by a complex process of coordination involving prime movers and synergists, which is controlled by the nerve supply (Figs. 3, 4, 5, 6, and 7).

Fig. 3 Illustration of the major group of muscles attached to the proximal and distal fragment in a subtrochanteric femur fracture. The proximal fragment is flexed, abducted, and externally rotated and the femoral shaft is adducted and shortened [13] Fig. 4 Illustration of various displacements happening in femoral fracture types – (a) varus, flexion, and external rotation in proximal fractures; (b) varus, internal rotation, and angular deformity in mid-shaft fractures; and (c) valgus and recurvatum in distal fractures

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Fig. 5 Physiological forces acting on the bone cause deformities in the presence of fracture. This deformity is reversed by fixation in reduced position

Fig. 6 Illustration of the deforming forces in proximal humeral shaft fractures. The pectoralis major adducts and internally rotates, while the deltoid abducts the proximal humerus

Management of Fractures Without Implants When there is a fracture of bone – one of the following scenarios can happen: An undisplaced fracture remains in the pre-injury position. Implants may not be necessary to treat such a fracture and an extraneous support such as a cast or slab or brace which prevents fracture mobility may be sufficient to relieve pain. Rest and immobility may allow the bone to heal by itself [14].

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Fig. 7 Use of a proximal humeral locking plate for a proximal humerus fracture

Some partially displaced fractures have serrated fracture edges which are locked into each other and prevent further displacement. This is known as an impacted fracture [4]. Such a fracture can be reduced (or disimpacted) by another reversing extraneous force (such as traction). In such a case it may be possible to avoid implant usage as the fracture components are not mobile and can progress to healing. Immobility is a factor which promotes union. The position of an impacted fracture is usually acceptable without much angulation. A certain degree of shortening however may be unavoidable. A good example of this type of fracture would be an impacted distal radial fracture with a stable fracture line. In the past, certain stable valgus fractures of the proximal femur were also treated conservatively. Currently, however, almost all fractures of the proximal femur are being fixed (Fig. 8) [11]. In a third scenario – gravity acts as a force of traction and gradually over a period of weeks reverses the deforming and displacing force. A prime example of that would be treatment of a slightly displaced greater tuberosity proximal humeral fracture where the position improves after a few weeks in a sling or a U-slab, the weight of which adds to the gravitational pull (Fig. 9) [15].

Management of Fractures with Implants In many cases, however, the nature of the injury does not allow conservative options. In such a situation the orthopaedic surgeon has to follow a different plan. Here we are only dealing with the basics and principles. The rest of the book has entire sections devoted to detail. The plan can be summed up in three simple words starting with R:

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Fig. 8 Anteroposterior radiograph of a valgus impacted neck of femur fracture

Fig. 9 Use of the aid of gravity for fracture reduction and healing

Reduce Restore the original anatomy of the displaced bone by reversing the deforming forces. There are several methods: Closed reduction – when the deforming forces are reduced without breaching the overlying soft tissue envelope. Open reduction – when the bone is surgically exposed to the exterior and the fracture fragments returned to the undisplaced state as best possible.

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Fig. 10 Illustration of the use of a femoral distractor for fracture reduction before fixation with a locking plate

Direct reduction – when the surgeon uses his hands or instruments to manually restore anatomy. Indirect reduction – when a fracture table or an instrument such as a femoral distractor is used (Fig. 10). Usually these are used when a lot of strength (more than the physical strength or capacity of the surgeon) is required to reduce the fracture. Sometimes only one component of a bone needs reduction such as a fractured greater trochanter in proximal femoral nailing. In such a case Schanz screws are used as a joystick. Similar functions can be performed by K-wires in smaller bone. Some of the modern implants are designed in such a way that they themselves are able to reduce bone. Most manufacturers expressly discourage this practice due to legal issues.

Retain (with Implants) An orthopaedic implant as used in traumatology is a manufactured device used to support damaged or injured bone. The purpose is to keep (retain) the fracture fragments in the reduced position. Various types of implants perform retention of fracture fragment in several different ways. Here only the principles are enumerated. Detail will be found in the individual chapters and sections of this book.

Plates and Screws A plate lies on a fractured bone (onlay implant) (Fig. 11). It has slots for screws. The screws have two parts. The proximal part is tightly attached to the plate. The distal part of the screw holds one fracture fragment. Frequently this is the opposite cortex

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Fig. 11 Illustration of an onlay implant

of the bone which is strong allowing “purchase” to the screw. In traditional plates, the bone is pulled to the plate and held tightly. Sometimes it is necessary to use locking plates with locking screws (when the hold of metal on bone is tenuous either due to poor bone quality or due to osteoporosis of the fragment). In such cases a system is used when the locking screw head obtains strength of fixation from the locking slot of the plate primarily and not from its grip onto bone. The plate has to be sufficiently strong and long so that the fractured fragments act as one bone. A good implant and technically correct fixation will not allow relative movements of the fractured components. It will however allow full movement of the adjacent joints. This is necessary for rapid union and prevention of malunion and allows optimum return of function and range of motion.

Rigid Nails To a lay person, the term “nail” can be a misnomer. It should perhaps be called a rod. In fact, this term is still in use in some parts of the world like the USA. To be more particular, as per presently used terminology, a nail has small holes drilled at both ends through which screws or pins are inserted to fix the device to the bone. Whereas rods are inserted inside the bone but are not fixed at the ends with screws or pins. However, often the term “nail” is used to address both these devices [16]. We will continue to use the term “nail” for the purpose of this book. A nail lies within the medullary cavity (inlay implant). Modern nails have slots for screws. One part of the nail lies within the proximal part of the fracture and another within the distal part. Each of these fractured components is held by screws to the nail. Modern nails have more locking options that allow good purchase of the bone to the nail. This is particularly important for fracture fragments in proximal or distal parts of the bone. Nails need to be sufficiently strong and long to prevent the deforming muscle pulls at the fracture site. Again, similar to plates, a properly fixed nail allows relative stability to the fracture components while permitting a good range of movement at the joint interface allowing early weight bearing and rehabilitation (Fig. 12). TENs (Titanium Elastic Nails) This is a nail variant often used in children. Usually they have no locking screws and the nails are flexible (elastic). They are able to follow the medullary cavity by bending slightly. They are usually inserted in pairs with three-point contact and give rigidity by counteracting the elasticity of each other. This allows the TENs to hold continuity in

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Fig. 12 Anteroposterior and lateral radiographs of the leg showing the use of an interlocking intramedullary nail (inlay implant) for fixation of a tibial shaft fracture. The patient also had a medial malleolus fracture that was fixed with malleolar screws with washer

the fracture (Fig. 13). However, these nails are not strong enough for immediate movement as they are non-rigid devices and cannot offer absolute stability [17]. Children’s fractures unite very quickly and usually the stability offered by TENs is sufficient. Also, TENs has to be removed rapidly as lack of anchorage allows it to migrate to undesirable parts of the body or penetrate adjacent neurovascular structures. Early removal of implants is a necessity in paediatric fractures as the bone can overgrow metal making it difficult to remove later. TENs therefore are appropriate for many paediatric fractures. TENs also has some limited usage in adult fractures in special cases where continuity rather than strength and rigidity is required. They have been used in humerus, radius, and ulna fractures and occasionally in geriatric femoral fractures (where the patient is not fit for major surgery). However, for these patients better implants are available today.

External Fixators In some open fractures, internal fixation can lead to infection. In such cases, the fracture is held indirectly by putting the screws in normal bone and holding the entire bony component as a single piece with the help of an external rod (Fig. 14). This method allows relative stability of the fracture but avoids the introduction of a foreign body in potentially infected tissues which can aggravate it. Avoiding internal fixation in wartime situations with contaminated wounds was an important lesson in orthopaedics and part of our learning curve in surgical physiology [18]. External fixation was found to save lives and limbs. Today, however, if the grade of an open fracture and the tissue contamination is low, external fixation may not be required in every case. This is because of the invention of strong IV antibiotics, good wound debridement, and modern wound

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Fig. 13 Illustration and radiographs showing the concept of elastic nailing in paediatric long bone fractures. The nails do not cross the physeal plate and hence do not impede the growth of the physis Fig. 14 Illustration of the use of an external fixator in an open tibia fracture

coverage techniques. If, however, the fracture is severely contaminated or exposed to organic products, early internal primary fixation can have disastrous consequences. In such a patient, external fixation is the only option available even today.

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External fixation has several other important applications which have only recently been appreciated. Some badly damaged fractures near the knee (proximal tibia) or ankle (distal tibia) develop wound problems if internally fixed too early. This is because they have internal degloving injuries which compromise nutrition to the affected part leading to wound sloughing and/or infections [19]. In such a case a two-stage fixation is done – the first stage with an ex-fix. A spanning ex-fix is applied allowing the soft tissues to recover. This will also allow the surgeon to purchase time to plan his surgery. This time is used fruitfully to conduct investigations such as a 3D-CT or in improving the general condition of the patient. The dictum span-scan-plan was born leading to improved outcomes in these difficult subgroups of fractures. Once the condition of soft tissues and the general condition of the patient are stabilized, a second-stage surgery is conducted. This is usually an internal fixation of the fracture so that mobilization of the joints can be commenced. This conversion to ORIF takes about 2–3 weeks or whenever the conditions for safe internal fixation are optimum. The reason the ex-fix is changed after 2–3 weeks is because ORIF gives better fracture stability and is more suitable in the long run for healing and rehabilitation. Also, long-term external fixation gives rise to bone infections some of which are difficult to eradicate.

Cannulated Screws This is a novel system where the principles of minimally invasive surgery are married to the intelligent usage of a C-arm. The fracture is carefully localized with the imaging device and the fracture reduced using minimalistic techniques. A small access point in the bone is identified often with a stab incision carefully staying away from important neurovascular structures. A guide wire is used to penetrate the fracture at the desired location. Once we are satisfied with our position, we railroad a cannulated screw (with a hollowed interior) over the guide wire and compress the fracture to the desired effect (Fig. 15). Kirchner Wires Kirchner wires are devices similar to the skewers in the preparation of meat dishes over a fire. They are firm and straight and come in different diameters. They hold pieces of bone together. Since the K-wire is a fragile implant it works well where the demand for strength is low, as in finger fractures, wrist injuries (Fig. 16), paediatric fractures, or where they can be supplemented with a cast or the force of gravity (distal humeral fractures). Stainless Steel Wires and Cables These implants are used as part of orthopaedic constructs such as tension band wiring, cerclage wires, etc. The wires are looped and twisted. Knots are applied using special tools. This creates pressure on fractured bones holding them together or to implants. Frequently, they are used in avulsion fractures to counteract the strong tendinous pull of the quadriceps (Fig. 17), triceps (Fig. 18), or rotator cuff (which can pull a part of bone to an undesirable location). Stainless steel wires are wires that

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Fig. 15 Illustration showing percutaneous use of a cannulated cancellous screw for fixation of a medial femoral condyle fracture Fig. 16 Illustration showing the use of Kirschner wires for the fixation of a distal radius fracture

are malleable and stored in loops. Cables work on the same principle with designs copied from engineering allowing greater strength per unit of metal.

Replacement of Fractured Bones with Prosthesis Bone healing cannot happen unless there is an adequate blood supply to the component parts. Sometimes fractures occur in parts of the bone where the blood supply is badly damaged. An example of this is an intracapsular neck femur fracture (Fig. 19). At other times the quality of the bone stock is so poor or the fracture so comminuted that a bone preserving fixation is not an option as in the proximal humerus or around the elbow joint. In such a situation the surgeon might realize that the chances of achieving union of the fracture are low and decides to replace the part of bone with an artificial

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Fig. 17 Illustration and radiographs showing use of stainless steel wires and cables in the form of tension band wiring for fixation of a patella fracture

Fig. 18 Illustration and radiographs showing use of stainless steel wires and cables in the form of tension band wiring for fixation of an olecranon fracture

Fig. 19 Illustration and radiographs showing use of a hemiarthroplasty prosthesis for replacement of the head of femur in a patient with fracture of the neck femur

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implant such as a prosthesis. This approach was initially used in the proximal femur with success [20]. Gradually it has been extended to the shoulder and other joints. However, success at the knee or elbow joints have been limited till date.

Rehabilitation Once the fracture fragments are satisfactorily fixed, anatomy is restored. Now is the time to restore physiology. Movement is life is an appropriate mantra coined by the AO group [21]. The joints adjacent to the fractured bone have to be exercised adequately so that early return to function is possible. Rehabilitation is a very important component of traumatology and influences outcomes. However, the details lie beyond the purview of his book. All we need to understand is that good fixation of bone is necessary for good rehabilitation and movement. And for the good fixation of bone we require good implants.

Bone Augmentation Techniques These are not orthopaedic implants. However, they are a very important aspect of trauma surgery and have been mentioned here for the sake of completing this concept. Occasionally a surgeon has to work with insufficient quantity or very poor quality bone. In such a scenario he/she might have to supplement the available bone with external bone or its substitutes. The purpose is usually one of the following: • • • •

Adding strength Adding biology Plugging holes and filling gaps Speeding up union

The best source of bone is from the patient’s own resources (autograft). Usually bone from the iliac crest is chosen though other sources of rich cancellous bone may be used (Fig. 20). Sometimes a fibular strut is used as inlay strength. Cortico-

Fig. 20 Illustration of the use of iliac crest autograft for filling up bone defect in a tibial shaft fracture with bone loss

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cancellous may also be chosen as a composite source of strength as well as for biology. Allographs (from sterilized cadaveric bone) are often used to fill in large gaps if the hospital has access to a bone bank. Autografts are better than allographs in all respects but the supply is finite. Bone substitutes are synthetic substances which can also be used as fillers. They are usually calcium-sulphate variations. Occasionally growth factors such as BMP may have a role to play. Ceramic substitutes such as hydroxyapatite are used in arthroplasty and have a very limited role in trauma.

Conclusion The science of orthopaedic trauma implantology and its evolution is quite fascinating when studied holistically. We begin to see the patterns in change and direction of progress. Modern medicine is often about seeing associations in disease – describing and understanding them and finally treating them. Orthopaedic trauma implantology combines bioengineering principles with the biology. By a close study of this subject, we begin to see patterns from among previously seemingly isolated and random inventions. Reptiles, fish, amphibians, and mammals coexisted for millennia but only the close analysis of their characteristics revealed how each species or genus evolved, competed among themselves, merged from one to another, and survived or died out. Orthopaedic implants while inanimate have had their own evolution. They too changed, adapted, evolved, and competed for dominance and survival. Most of them disappeared from the narrative like an extinct species or merged into other implants. In this book, we will only deal with important inflexion points ignoring the irrelevant footnotes. ▶ Chapter 5, “Orthopaedic Nails Versus Orthopaedic Plates: An Evolutionary Tale for Dominance and Relevance,” elaborates on this specific topic comparing the evolution of nails and plates in limb fractures. Although most of the described implants are state of the art, the most critical factor about successful treatment for the patients is the surgeon! All the above discussion of nail, plate, etc. breaks down to the final question: With which implant will you obtain the best result? We hope that by giving relevant details about various implants we can help you, and surgeons might make an informed and appropriate choice for a given patient and fracture.

References 1. Hodgson S. AO principles of fracture management. Ann R Coll Surg Engl. 2009;91(5):448–9. https://doi.org/10.1308/003588409X432419f. PMCID: PMC2758473. 2. Gaviria L, Salcido JP, Guda T, Ong JL. Current trends in dental implants. J Korean Assoc Oral Maxillofac Surg. 2014;40(2):50–60. https://doi.org/10.5125/jkaoms.2014.40.2.50. Epub 2014 Apr 28. PMID: 24868501; PMCID: PMC4028797.

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3. Gomez PF, Morcuende JA. A historical and economic perspective on Sir John Charnley, Chas F. Thackray Limited, and the early arthoplasty industry. Iowa Orthop J. 2005;25:30–7. PMID: 16089068; PMCID: PMC1888784. 4. Meinberg EG, Agel J, Roberts CS, Karam MD, Kellam JF. Fracture and dislocation classification compendium-2018. J Orthop Trauma. 2018;32(Suppl 1):S1–S170. https://doi.org/10.1097/ BOT.0000000000001063. 5. Thomas TP, Anderson DD, Willis AR, et al. A computational/experimental platform for investigating three-dimensional puzzle solving of comminuted articular fractures. Comput Methods Biomech Biomed Eng. 2011;14(3):263–70. https://doi.org/10.1080/ 10255841003762042. 6. Wei J, Zeng L, Li S, Luo F, Xiang Z, Ding Q. Relationship between comorbidities and treatment decision-making in elderly hip fracture patients. Aging Clin Exp Res. 2019;31(12):1735–41. https://doi.org/10.1007/s40520-019-01134-5. 7. Jin W, Chu PK. Orthopedic implants. In: Narayan R, editor. Encyclopedia of biomedical engineering. Elsevier; 2019. p. 425–39. 8. Kumar A, Misra RD. 3D-printed titanium alloys for orthopedic applications. In: Titanium in medical and dental applications. Woodhead Publishing; 2018. p. 251–75. 9. Güngör NK. Overweight and obesity in children and adolescents. J Clin Res Pediatr Endocrinol. 2014;6(3):129–43. https://doi.org/10.4274/Jcrpe.1471. PMID: 25241606; PMCID: PMC4293641. 10. Vi L, Baht GS, Whetstone H, et al. Macrophages promote osteoblastic differentiation in-vivo: implications in fracture repair and bone homeostasis. J Bone Miner Res. 2015;30(6):1090–102. https://doi.org/10.1002/jbmr.2422. 11. Ly TV, Swiontkowski MF. Management of femoral neck fractures in young adults. Indian J Orthop. 2008;42(1):3–12. https://doi.org/10.4103/0019-5413.38574. PMID: 19823648; PMCID: PMC2759588. 12. Dhillon MS, Prabhakar S, Prasanna C. Preliminary experience with biodegradable implants for fracture fixation. Indian J Orthop. 2008;42(3):319–22. https://doi.org/10.4103/0019-5413. 41856. PMID: 19753159; PMCID: PMC2739475. 13. Froimson AI. Treatment of comminuted subtrochanteric fractures of the femur. Surg Gynecol Obstet. 1970;131(3):465–72. 14. Sarmiento A, Latta LL. The scientific basis of closed functional management of fractures. In: Closed functional treatment of fractures. Berlin/Heidelberg: Springer; 1981. https://doi.org/10. 1007/978-3-642-67832-5. 15. Thompson RG, Compere EL, Schnute WJ, Compere CL, Kernahan WT Jr, Keagy RD. The treatment of humeral shaft fractures by the hanging cast method. J Int Coll Surg. 1965;43:52–60. 16. von Keudell A, Collins M, Jupiter JB. Principles of fracture fixation: plates/screws and intramedullary nails. In: Case competencies in orthopaedic surgery. Elsevier; 2017. p. 223–38. https://doi.org/10.1016/C2014-0-01321-4. 17. Saseendar S, Menon J, Patro DK. Complications and failures of titanium elastic nailing in pediatric femur fractures. Eur J Orthop Surg Traumatol. 2010;20(8):635–44. 18. Manring MM, Hawk A, Calhoun JH, Andersen RC. Treatment of war wounds: a historical review. Clin Orthop Relat Res. 2009;467(8):2168–91. https://doi.org/10.1007/s11999-009-0738-5. 19. Lekuya HM, Alenyo R, Kajja I, et al. Degloving injuries with versus without underlying fracture in a sub-Saharan African tertiary hospital: a prospective observational study. J Orthop Surg Res. 2018;13:2. https://doi.org/10.1186/s13018-017-0706-9. 20. Robertson GA, Wood AM. Hip hemi-arthroplasty for neck of femur fracture: what is the current evidence? World J Orthop. 2018;9(11):235–44. https://doi.org/10.5312/wjo.v9.i11.235. PMID: 30479970; PMCID: PMC6242732. 21. Bavonratanavech S. The origins of the AO Foundation. BKK Med J [Internet]. 2012 Sep 20 [cited 2020Sep.11];4(1):117. Available from: https://he02.tci-thaijo.org/index.php/ bkkmedj/article/view/218000

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The Drivers of Change in Orthopaedic Trauma Implant Designs Arindam Banerjee, Saseendar Shanmugasundaram, and Shiuli Dasgupta

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Patient-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fracture-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surgeon-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Infrastructure-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Medical and Ancillary Infrastructure (Non-exhaustive List) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surgical and Ancillary Infrastructure (Non-exhaustive List) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Impact of Material Sciences and Progress in Other Non-medical Specialities . . . . . . . . . . . . . . . . . . Industry-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . War-Driven Demands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Orthopaedic implantology is a vastly changing subject. Orthopaedic surgeons face varying demands in patient care and varying patterns and combinations of fractures, all changing based on behavioural and activity changes of the population. In this chapter, we discuss the drivers of this change in order to enable the surgeon to choose the best implants.

A. Banerjee (*) Orthopaedic Surgery, NH Narayana Superspeciality and Multispeciality Hospitals, Howrah, West Bengal, India e-mail: [email protected] S. Shanmugasundaram Department of Orthopaedics, Sri Lakshmi Naryana Institute of Medical Sciences, Puducherry, India S. Dasgupta KPC Medical College and Hospital, Kolkata, West Bengal, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_2

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Keywords

Orthopaedic implantology · Fracture patterns · Changing demands · Changing infrastructure · Early recovery

Introduction Change is the only constant in life. (Heraclitus, Greek philosopher)

This statement is true for all sciences. And it is expressly valid for the science of orthopaedic trauma implantology. In order to understand why an implant design keeps changing it is necessary to clearly understand the drivers of this change. These drivers are the demands which an implant must satisfy in order to be successful. The demands are enumerated below: • • • • • •

Patient-driven demands Fracture-driven demands Surgeon-driven demands Infrastructure-driven demands Industry-driven demands War-driven demands

Patient-Driven Demands Every patient is different and has specific requirements in order to lead his or her life to their full potential and desire. We list here (not exhaustively) several patient factors which influence the design of orthopaedic implants: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Age Sex BMI Race (anthropometric measurements) Activities of daily living (ADL) Occupation Leisure and recreational activities Level of sporting activities Diseases related mainly to bone (osteoporosis and diseases which alter bone-like malignancy) Diseases bearing on the musculoskeletal system (e.g., rheumatoid arthritis and hormonal problems) Comorbidities Other associated injuries (e.g., impending ARDS) Economic considerations

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Fracture-Driven Demands Every fracture has a unique pattern. This is often called the “personality” of the fracture. Traditionally fractures have been evaluated by sets of radiographs. And radiographs have always been two-dimensional representations on an X-ray plate or screen (anteroposterior and lateral views and occasionally special views) of a threedimensional object. Naturally, it provides incomplete information allowing partial or inadequate assessment. Thus, classifications of fracture patterns which have been made in the past are often found wanting. One of the game changers in the recent past is the advent of the 3D CT scan. This allows us to assess the fracture pattern in three dimensions. Also, the current software technology allows us to look at structures virtually in incredible detail. Three-dimensional printing is a further extension of this concept allowing the surgeon to convert “virtual” images into “real” models, as well as allowing the surgeon to template fractures better and plan surgery more comprehensively. In the past, orthopaedic surgeons focused exclusively on bone neglecting the injured surrounding soft tissue which had a significant bearing on the stability of the fracture. Historically, the only time soft tissue dynamics was considered was in avulsion fractures where a tension band wiring was done to counteract the strong forces of the triceps or quadriceps [1, 2]. Consequently, surgeons and radiologists realized that they had often misjudged the original fracture pattern by restricting their assessments to radiographs. The new understanding of fracture dynamics is leading to reclassification of fractures and the consequent redesign of implants. Sometimes the original concept of the implant was retained and additional features were added like conversion of first-generation nails and plates into a third-generational model [3].

Surgeon-Driven Demands Every surgeon in the world is unique. They are not a homogenous entity. These differences must be appreciated by the implant designers so that they can perform safe surgery. We enumerate some of the differences between them (not exhaustive): 1. 2. 3. 4. 5.

Surgical training and background, experience, and skills Risk taking capacity and ability Access to infrastructure (sophistication of hospital and department) Support level from surgical team Ancillary support available – paramedics, other allied disciplines, as well as administrative and financial

Infrastructure-Driven Demands This headline is particularly important. Modern-day implantology is getting more and more complex. In order for the surgeon to be able to deliver safe and predictable surgical outcomes, (s)he would require a proper backup system. This has been

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shown effectively by the improvements in outcome seen after the introduction of ATLS protocols [4, 5]. Orthopaedic and trauma infrastructure can be categorized under three broad headings: • Medical and ancillary infrastructure • Surgical and ancillary infrastructure • Impact of progress of material sciences and progress in other non-medical specialities

Medical and Ancillary Infrastructure (Non-exhaustive List) 1. Intensive care backup 2. Medical teams available for patient care 3. Ancillary medical teams like dialysis unit, cath labs, etc.

Surgical and Ancillary Infrastructure (Non-exhaustive List) 1. Anaesthetic backup including access to skill sets such as regional blocks and anaesthetic workstations 2. Other trauma subspecialities such as plastic surgeons, neurosurgeons, and general surgeons 3. Cutting tools including power saws, reamers, drills, and diathermy 4. Tourniquets 5. Patient transporting devices – equipped ambulance, pelvic binders, and portable life-saving devices 6. Radiolucent orthopaedic tables 7. Imaging devices – C-arm, CT scans, ultrasonograph (abdominal trauma), and Doppler scans (vascular injuries) 8. Basic orthopaedic operating sets and special sets for specific trauma surgery The ability of the surgical team to practice safe surgical implantology depends on the summation of the above factors. In the absence or suboptimum availability of key infrastructure such as C-arm, tourniquets, or fracture tables, the surgeon may have to consider a different choice of implants. An example would be the necessity of doing an open K-nailing instead of a closed interlocking nail when facilities are insufficient.

Impact of Material Sciences and Progress in Other Non-medical Specialities This subgroup is perhaps the least appreciated. Sometimes a particular operation is technically difficult or even impossible because allied material sciences have not developed. Once the necessary progress in the allied field has happened it is possible to make the quantum jump (Fig. 1).

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Fig. 1 Illustration of how technology evolves over time

As an example, the invention of the flexible reamers in orthopaedics allowed long bone nailing to move from a retrograde surgery to an antegrade procedure. Similarly, the advent of titanium alloys allowed implantology to become MRI friendly.

Industry-Driven Demands This is the elephant in the room that everyone avoids talking about. Industry thrives on change. If they stop innovating, competitors catch up and start bringing in “me too” products. Business flourishes if an industry can obtain first-mover advantage. Frequently a newer model is superior to the previous one. But occasionally these business-driven newer models are not as good as the old product. This often may lead to abandonment or further change in the new technique or implant leaving its path many unsatisfied customers (both patients and surgeons). In fact, it is safe to say that the multiplicity and repeated remodelling of products is more due to the orthopaedic trauma industry than any other factor [6]. It is also important to realize that the industry is far from monolithic. It encompasses many stakeholders including scientists and surgeons (backed by industry) who are always trying to break technical boundaries. It is like a strong vehicle capable of driving progress forward, backward, or sideways but also is accident prone. Flexibility is both a strength and weakness in this model! Human progress in any field has never been linear. It can be compared to an S-shaped curve. But it may not be a single curve, rather a cumulation of many. Also, as the top of a curve of human progress plateaus due to a road block, a bypass is

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Fig. 2 Moore’s law in orthopaedic implantology

found by a better technology – a medical form of Moore’s law but perhaps not so dramatic (Fig. 2).

War-Driven Demands If we analyse the historical outcomes of treatment of the same fractures during the First World War, the Second World War, and the Vietnam war, we will see that the results have continued to improve with time. This is because a war is a challenge and crisis like no other. Often to survive and sometimes to remain ahead of the competition, human beings must innovate and find better technologies. Techniques improve and the next generation of implants get invented. This leads to better outcomes [7]. During peacetime, breakthrough military technologies are adapted for civilian and medical use. War-time submarine technology of the 1940s led to the development of the ultrasound in 1956 and to its later generation progeny such as echocardiograms and the handheld Doppler devices just to name a few adaptations [8, 9].

Conclusion Progress in any scientific or technical sphere is expected and is often inevitable. Saturation or stifling of any subject leads to its demise. The advancement of orthopaedic trauma implantology is not unique in any way. What is unique is how

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little of this progress has been studied and documented in orthopaedic academic literature. We have enumerated the drivers of change of design of implant in this chapter. In ▶ Chap. 5, “Orthopaedic Nails Versus Orthopaedic Plates: An Evolutionary Tale for Dominance and Relevance,” we will focus on two groups of implants which have continued to develop, namely orthopaedic plates and nails and try to show how and why this change has occurred. We have charted and compared their progress and evolution – their fight to remain dominant and relevant. ▶ Chapter 6, “Internal Fixation Versus External Fixation in Orthopaedic Trauma Implantology,” will conduct a similar exercise on external fixation versus internal fixation.

References 1. Benjamin J, Bried J, Dohm M, McMurthy M. Biomechanical evaluation of various forms of fixation of transverse patellar fractures. J Orthop Trauma. 1987;1(3):219–22. https://doi.org/10. 1097/00005131-198701030-00004. 2. Zderic I, Stoffel K, Sommer C, Höntzsch D, Gueorguiev B. Biomechanical evaluation of the tension band wiring principle. A comparison between two different techniques for transverse patella fracture fixation. Injury. 2017;48(8):1749–57. https://doi.org/10.1016/j.injury.2017. 05.037. Epub 2017 May 29. PMID: 28622833. 3. Russell TA. Intramedullary nailing: evolutions of femoral intramedullary nailing: first to fourth generations. J Orthop Trauma. 2011;25(Suppl 3):S135–8. https://doi.org/10.1097/BOT. 0b013e318237b2eb. PMID: 22089849. 4. Vestrup JA, Stormorken A, Wood V. Impact of advanced trauma life support training on early trauma management. Am J Surg. 1988;155:705–7. 5. Anderson ID, Woodford M, De Dombal FT, et al. Retrospective study of 1000 deaths from injury in England and Wales. BMJ. 1988;296:1305–8. 6. Javaid M, Haleem A. Impact of industry 4.0 to create advancements in orthopaedics. J Clin Orthop Trauma. 2020;11(Suppl 4):S491–9. https://doi.org/10.1016/j.jcot.2020.03.006. Epub 2020 Mar 18. PMID: 32774017; PMCID: PMC7394797. 7. Manring MM, Hawk A, Calhoun JH, Andersen RC. Treatment of war wounds: a historical review. Clin Orthop Relat Res. 2009;467(8):2168–91. https://doi.org/10.1007/s11999-0090738-5. 8. Carovac A, Smajlovic F, Junuzovic D. Application of ultrasound in medicine. Acta Inform Med. 2011;19(3):168–71. https://doi.org/10.5455/aim.2011.19.168-171. 9. Zhou Y, Qiu W, Huang Z. Translational and emerging clinical applications of medical ultrasound. BioMed Res Int. 2018, 2018:Article ID 6908393, 2 pages. https://doi.org/10.1155/2018/ 6908393.

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Defining the Clinical and Radiological Endpoint of a Successfully Fixed Fracture Sriram Srinivasan, Amit Bishnoi, and Vasantha Kumar Ramsingh

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Clinical Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Radiological Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Callus and Consolidation on Radiographs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Bone healing is a complex biological process involving various anatomical and mechanical events along with expression of various genes, allowing changes in cells and leading to fracture union. There are primarily two ways the bone heals; primary bone healing and secondary bone healing. Primary bone healing in other words is direct intramembranous healing whereas the indirect bone healing involves both intramembranous and enchondral bone formation. In a well-fixed fracture, the bone is expected to heal with direct bone healing as the bone is anatomically reduced and fixation provides stable environment. We discuss the endpoint for a successful fixation based on clinical examination and radiological support. Fracture union remains largely a clinical diagnosis. The triad of displacement, stability, and biology dictates fracture union. In a well-fixed fracture, radiological

S. Srinivasan (*) Royal Stoke Hospital, Stoke-on-Trent, UK A. Bishnoi Leicester Hospitals, Leicester, UK V. K. Ramsingh Pilgrim Hospital, Boston, UK © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_3

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tests provide little evidence on healing line cutting cone mechanism. Pain, weight-bearing status, and clinical examination remain the tool of choice for surgeons in decision making. Keywords

Bone healing · Callus · Malunion · Fracture union · Radiological fracture union · Clinical fracture union

Introduction Bone healing is probably the most important essence of trauma and orthopaedic surgery. This lays the foundation for learning of biological process of bone healing and its interactions with implants that changes the environment with different strain and stresses. As Perren [1] described that the stiffness is the main function of bone and healing is the restoration of this stiffness. The cyclical transformation of tissues under different strain is a unique property of bone, and fracture fixation utilized this property to restore the bone function. The biological process is described in different phases which will be discussed in detail later in the chapter. These phases are controlled by biological signalling and sensitive to the mechanical environment. Primary and secondary healing of bone is well established where there is callus formation in the latter. Fixing the fracture of application of a device/plate shortens the different phases and possibly provides a quicker access to later stages of bone healing. The triad of displacement, stability, and biology is immensely helpful in decision making and lays the foundation for some basic principles for fracture management. 1. Reduction: of the displacement. 2. Fixation: to stabilize the fracture. 3. Biology: to aid fracture healing. Bone healing is all about controlling the cyclical micromotion. In early stages, the motion is reduced, but for later stages, micromotion is required for bone healing. This was once succinctly put by John Hunter as “fractures heal by a species of necessity”. Bone healing is variable and the healing time depends upon age, type of fracture, type of bone, etc. In essence it is dependent on blood supply. Blood brings the cells required for healing as we know “Cells form bone”. Abundant and rich blood supply is available in the thick periosteum of children, which helps to heal fracture earlier than the same injury in the elderly.

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Bone biology is crucial when deciding the treatment for a fracture. Orthopaedic hardware supports the bone but in the process the blood supply can be damaged and thus healing process can be compromised. Researchers have shown us to use the differentiation properties of Mesenchymal stem cells in bone healing. Different cells will make different tissues in different environment. Clinical use has been applied in non-unions and healing critically sized defects.

Clinical Features There is no precise definition of fracture healing that exists, due to disagreement between the clinicians. Definition of clinical fracture union encompasses absence of pain or tenderness at the fracture site on palpation, able to weight bear without any pain, and is more a clinician’s impression. Research done in the past is not quite sure whether clinical union corresponds to patient-related outcomes such as quality of life, pain, or function. The type of fracture healing that occurs with the fixation is with the compression plate, which is primary (direct) bone healing. With external fixation and intramedullary nailing secondary bone healing with enchondral ossification occurs. The most important factor that affects fracture healing is the blood supply. The above factor is important in consideration when choosing the mode of fixation for clinical union. There is a controversy about whether periosteal vascular system or the medullary system is important for the fracture Union. Using a plate and the screw for fracture fixation causes local Issues with the blood supply to the bone. Reamed intramedullary nail causes damage to the medullary blood supply. Other factors that can cause effects of fracture healing are bony soft tissue attachments, location of injury, and pattern of the fracture and mechanical stability of the fracture. Clinical examination plays a vital role in determining clinical union. Bhandari et al. in their work describe that ability to weight bear is the most important criteria in clinical union of fracture. Patients perceive clinical union differently but that of the surgeons it is important to use patient-related outcome measurements in clinical practice [2]. Other forms of validated measures such as SF 36 or musculoskeletal functional assessment are used as patient-related outcome measures for clinical union as end point. Functional Index for trauma has been developed to assess clinical fracture healing on the assessment of able to weight bear and pain [3]. Stiffness is an important property of the bone for it to perform its mechanical function. Fracture stiffness is important in bone healing for the bone to return to its best function. It is important to measure fracture stiffness as a part of clinical union. Fracture stiffness is the stiffness of healing structure without any immobilization support and it is measured by stiffness of soft issues as well as the bone. Stiffness is measured by the formula: stiffness ¼ load/displacement.

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Radiological Features Plain radiograph is the most commonly used tool to assess fracture healing. Low cost, easy access, and limited exposure to radiation work in favour of its widespread use. Measurement of fracture union in radiographs depends on the amount of callus formation, cortical bridging, and fracture gap filling [4]. Because of varying patterns of bone bridging (endosteal, periosteal, and intercortical) that can occur, quantitative assessment of fracture healing using radiology can be difficult. In their seminal paper on cross-sectional survey of 577 international orthopaedic surgeons, Bhandari et al. found there was a lack of consensus in the assessment of fracture healing and definition of non-union and malunion in tibial shaft fractures. Bridging of the fracture site by callus, trabeculae, or bone, bridging of fracture sites at three cortices, and obliteration of fracture line are the most common definitions of the fracture healing described in studies involving plain radiographs [5]. Over the years there were several scoring systems described to define radiological fracture union. The Lane-Sandhu scoring system [6] scores fracture healing from 0 to 5 based on the callus formation and estimation of stability of the fracture.

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Points 0 1 2 3 4

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Callus and fracture line No callus formation 25% callus tissue, fracture clearly visible 50% callus tissue, fracture line blurry 75% callus formation, fracture line barely visible 100% callus tissue, no fracture line

Whelan et al. in 2010 [7] developed a scoring system to assess the radiological union of diaphyseal tibial fracture after intramedullary nailing called Radiological Union Score for Tibial fractures (RUST) score. It is based on the anteroposterior (AP) and lateral radiographs of the tibial shaft. It is scored on the basis of visibility of fracture line and callus formation.

Score per cortex 1 2 3

Callus Absent Present Present with bridging

Fracture line Visible Visible Not seen

Each cortices on both AP (medial and lateral cortices) and lateral (anterior and posterior cortices) projections are scored to a minimum score of 4 where the fracture is definitely not healed and a maximum score of 12 which indicates the fracture has healed completely. Their study demonstrated substantial improvement in reliability and a reproducible tool of assessment of fracture healing in tibia. A further modification to RUST score was developed by Litrenta et al. in 2015 [8]. In the modified RUST score, a fracture with callus is subdivided into callus that is simply “Present” or “Bridging” which predicts the progression to fracture union. Therefore in the modified score each cortex is scored as below: Score 1 2 3 4

Callus No callus seen Callus present Callus present with bridging but fracture line visible No fracture line, callus remodelled

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Total score ranges from 4 to 16. In their study Litrenta et al. [8] compared the interrater agreement for RUST and modified RUST scores for metadiaphyseal fracture treated with nails and plates. They considered the fracture was united with the RUST score of 9 and modified RUST score of 11. There was a substantial agreement of modified RUST score than the RUST score and moderate agreement for fracture union with modified RUST. Ninety percent of the reviewers assigned definite union when the score was 10 (RUST) and 13 (modified RUST). Modified RUST value of 20 years) or permanently implantable device to preserve the function and stability of the joint and limb and enhance the quality of the life of the patient. These implants can be made up of ceramics, polymers, or metals that are mechanically stable and show minimal immune host response when implanted [16]. The biologically inert implants are known to minimize the implant-cell interactions [17]. These biomaterials have a layer of adsorbed proteins on their surface that promotes the formation of the provisional matrix and functions as a buffer between the implant and host tissue. 2. Biomaterials for regeneration – These biomaterials are aimed in regeneration of the lost tissue and structure and restore the function [18]. These biomaterials should degrade over a period of time while regenerating the lost matrices [19, 20].

Biomaterials of the Future An implant can be temporary, permanent, or bioabsorbable. Future orthopaedic implants will find their place in regeneration of the living tissue. The research will be concentrated more over the inherent qualities of biomaterials and their role in immune modulation. The focused assessment of biomaterial’s immune response may give rise to new set of immune modulating biomaterials that can direct the

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active innate immune system for better incorporation of the implants in the host bone or near normal tissue regeneration [21].

Manufacturing Technology Implant failure has always been a common problem in orthopaedic application that has been a prominent cause for pain and stress for the patients, increased rates of revision surgery, extensive antibiotic therapy with simultaneous increase hospitalization time, and health expenditure. Hence, selecting an optimum porous structure with an appropriate manufacturing process and surface modification approach will be crucial to combat the implant failure. The porosity and the design of orthopaedic implants play an important role in vascularization, diffusion of nutrients, and osseointegration. The commonly described techniques for porous design include computer-aided design (CAD), image-based design, implicit surface design, and topology optimization. The porous structures like titanium have been extensively fabricated with metal-based additive manufacturing methods such as electron beam melting (EBM), selective laser melting (SLM), and selective laser sintering (SLS). Moreover, chemical surface modification methods, such as acid etching, anodization, and coatings, are introduced to improve the mechanical properties and biocompatibility, increase surface roughness, and promote osseointegration and bone regrowth.

Additive Manufacturing or 3D printing Also known as rapid prototyping or 3D printing, this procedure is used to manufacture and fabricate different structures based on the solid model and involves building of the model layer by layer. Additive manufacturing has proven its potential to revolutionize the various applications across the medical sector. It is the layer by layer manufacturing process in which a computer-assisted predesigned model is sliced into layers and each layer is deposited successively on the previous layer to develop the final determined product [22]. The laser and electron beam powder additive manufacturing forms the next generation in additive manufacturing of orthopaedic metallic implants. The additive management stands apart from the routine procedures of manufacturing with its striking ability to form implants of shapes that cannot be formed with any other technologies. This property can be significantly favourable in manufacturing the patient-specific implants in extraordinary circumstances involving the complex anatomy encountered in malunited or dysplastic bones [22, 23]. Though the technology has numerous challenging issues in medical 3D printing and manufacturing, it has a potential of reducing the surgical times, enhancing patient recovery, and improving the anatomical alignment while simultaneously providing a good value for money in the future. 3D printing can also be utilized to manufacture routine implants in bulk quantities [15] (Fig. 4).

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Fig. 4 Various types of 3D printers

Additive manufacturing can also be used to produce different composite materials, e.g., PEEK with hydroxyapatite, to produce an implant with beneficial qualities of different metals/alloys. Formation of nano-PEEK/HA composites prevents

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Fig. 5 (a) Talus mould for 3D printing (b) 3D printed talus ready for implantation

debonding between the components. 3D-printed PEEK-titanium composites provide a modulus of elasticity closure to the bone and at the same time create a rough surface for osseointegration (Figs. 5, 6, 7, and 8). 3D printing to manufacture implants can be done by either creating the following: 1. Use of customized 3D-printed die casts 2. Direct alloy and biomaterial implant printing

Customized 3D-Printed Die Casts As the cost of direct metal printing is high, for mass production, traditional die cast can be used. The only difference is that the die is created using CAD model and subsequently 3D printed in acrylonitrile-butadiene-styrene (ABS). They may undergo secondary post finish processing.

Direct Metal Printing The gold standard for additive manufacturing is direct metal implant printing. As the cost of printing hardware decreases and availability becomes widespread, this particular segment will receive a major boost. One important aspect will be ensuring the quality of metal powders. Thus far, the industry standards and FDA regulations mandate the use of good-quality and rigorously tested products.

Surface Modification Various surface modification techniques are available which changes the surface characteristics of the implant. These changes are useful for osseointegration of the implant, can provide osteo-inductive properties, and can also be utilized to prevent infection.

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Fig. 6 3D printed acetabulum (titanium)

Major surface modification techniques are as follows: • Subtractive methods In these methods, part of the surface is removed from the implant to achieve desired changes in surface morphology, e.g., grit blasting, acid etching, or a combination of these. • Additive methods A layer with desired surface quality is added to existing implant surface, e.g., plasma spraying, pulsed laser deposition, sol-gel deposition, sputtering coating, and electron spray deposition.

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Fig. 7 3D printing in for cranioplasty

Fig. 8 3D printed calcaneum plate in calcaneum fractures

• Subtractive/additive methods A combination of both the techniques is used, e.g., anodization.

Coatings of Biomaterials The coatings of the orthopaedic biomaterial improve the mechanical properties and osseointegration, by enhancing the implant surface and osteoblasts reactions at the implant surface and surrounding tissue. The coatings (organic and inorganic components) establish the foreign implant material reactions, accelerating the early and strong fixation of implant to the bone [24–26].

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Inorganic Coatings The calcium phosphates (CaP) are known to have identical mineral phase to the bone, HA being the more similar in phase. Coating of the implants increases the signalling of the cells at the implant surface. Moreover, the CaP ceramics form a chemical bond between the implant and the tissue, enhancing the bioactivity properties. The interaction is reported to form a carbonate apatite layer on the surface of implant that is chemically similar to the bone that enhances healing process. The plasma spray is the most common method of application among the well-described magnetron sputtering, pulsed laser deposition, and sol-gel-deposition. The plasma sprays are used to aim powdered hydroxyapatite on the implant surface; this solidifies on the surface of the implant as a coating. The advantages of this are the higher deposition rates and the ability to coat larger area. On the contrary, it is difficult to coat areas with irregular shapes in uniform fashion. Also, the strength of the HA coating is decreased after prolonged immersion in simulated body fluids, due to degradation of intermolecular bonds in the coating, indicating the questionable long-term performances of HA coatings. There is a poor control over the coating thickness and final morphology of the coating, which has adverse effects on the osseointegration.

Organic Biomolecule Coatings The organic biomolecule coatings are used to immobilize the organic proteins, enzymes, and peptide chains over the implant surface in order to improve the osseointegration and tissue response. These coatings are applied by methods like immobilization and physical deposition.

Physiochemical Adsorption This is the process in which the implant is immersed in the peptide contained under controlled conditions allowing the molecules to physically entrap and adsorp onto the implant surface. This method does not ensure the controlled deposition of the biomolecules which is needed for initiated interactions with the tissue. Add to this, the desorption of the biomolecules is also uncontrolled.

Covalent Binding This method is used widely to bind the biomolecules on the implant surface with covalent bonds, in order to immobilize the peptides, enzymes, and proteins on the surfaces of titanium implants. Again, this process does not allow the control over the surface density of the biomolecules, which affects the biological response of the body to implant.

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Peptide Inclusion In this method, the peptide sequences are immobilized onto the titanium surfaces that promote the cell adhesion. The cellular responses and processes can be controlled by the immobilized peptide chains and extracellular matrix proteins. This influences the cell adhesion, proliferation, migration, morphological change, gene expression, and cell survival, through intracellular signalling.

Ion Implantation It is a physical process of bombardment of ions in the electric field on the surface layer of the substrate in a vacuum. This method allows us to produce high-purity layers with ability to control concentration and impurity and depth distribution with higher precision [27, 28]. The process is conducted below the critical temperatures that don’t alter the mechanical properties of the implant material. The main application of this method is to improve the osseointegration of titanium implants. This technique can also be used in conjunction with HA coating, enhancing the precipitation of HA in solution. The oxygen ions implanted over titanium have been reported to improve the stability of the oxide layer; similarly, the cobalt ions onto titanium alloy have been proven to improve osseointegration [29]. It has also been reported that this process improves the blood compatibility and antibacterial properties on the polymer substrates [30]. PEEK implants have a smooth surface, and thus, osteo-integration of the surface of PEEK implants is often compromised. This leads to loosening of the implant, especially spine interbody cages. Surface of the PEEK implant can be converted to a trabecular structure using 3D printing technology. This trabecular surface facilitates osseointegration. Surface of the PEEK cages can be plasma sprayed with titanium alloy which provides better osseointegration of implant surface. However, delamination of titanium surface during cage insertion can lead to localized inflammatory reaction due to metal particles. Titanium layers can also act as a carrier for bone morphogenetic protein (BMP) to enhance fusion. Coating PEEK surface with mouse betadefensin (MBD) showed inhibition of bacterial growth. Experimental models have also shown antibacterial activities of implant surface coated with simple calcium phosphate or gentamicin mixed with hydroxyapatite. Similarly, a titanium implant surface can also be altered for better osseointegration. Acid surface etching, HA coating, and trabecular tantalum coating on surface of titanium implant will render surface more biocompatible for better osseointegration.

Patient-Specific Orthopaedics The orthopaedic implant companies have gradually begin to focus on the biological differences in the patients and in turn produce the more anatomical compatible

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implant devices that will improve the implant longevity and patient-reported clinical outcomes and in turn reduce the healthcare expenditure. With the ease of availability of the customized and patient-specific orthopaedic implants, the concept of one size fits all will not be an appropriate choice for improving the clinical outcomes. In the past, getting the patient-specific implants meant a compromise in the speed or cost. The sequence of events to get these customized implants included the following steps: 1. 2. 3. 4.

Computed tomography (CT) scan of the patient. Scan sent to implant company. Implant solution is designed and a model is sent back to surgeon. Surgeon’s approval and implant manufactured.

The process was time-consuming (many weeks), when the patient is suffering, and with increasing costs burden on either the patient or healthcare systems. The patient-specific implants were reserved for knee revisions or tumour surgeries. The patient specific instrumentation (PSI) offers several intraoperative as well as postoperative advantages:

Intraoperative Advantages • • • • • •

Smaller incision than the conventional methods Reducing the surgical time by reducing certain surgical steps Reducing instrumentation and number of trays opened Minimizing the mismatch between the bone and the jigs for instrumentation Change in planned size of implant Minimizing the recuts

Postoperative advantages • • • • •

Better and anatomical restoration of the lib axes Shorter surgery lessen the blood loss Faster post-surgery rehabilitation Better postoperative functional parameters Lesser instrumentation, low revision rates, small surgery time, less personnel employed, and decrease in cost of inventory and maintenance that supports the cost-effectiveness.

PSI in the last decade was logistically a difficult concept to introduce in orthopaedics. The present era is just the beginning of patient-specific orthopaedics, it will be interesting to see how the stakeholders and manufacturing technology will adapt to abovementioned perceived advantages of PSI in an efficient manner. The future has to offer a huge introduction of patient-specific implants that will incline the dynamics more toward the patient care and satisfaction.

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Future Directions in Implantology The additive manufacturing techniques involve high energy that affects the mechanical properties of the structure; the future direction will be more focused on the techniques that do not disturb the mechanical properties of the material. The artificial intelligence optimization methods can be applied to topology optimization in order to achieve groups of optimized solutions. The chemical surface modifications are short-term solutions; future directions should include the study measures to increase the longevity of these coatings. The future surface modifications should be directed toward improving the antibacterial properties of the coatings. Investigations and moderating the changing parameters related to final morphology and bacterial properties of the substrate are currently being tested.

In the Era of Digital Orthopaedic The widespread inculcation of the newer technologies enabling the healthcare providers to provide care for the patients remotely has potential to change the expectations of the way the care is provided in orthopaedic surgery. In the future era of digital orthopaedics, we will see a gradual and non-disruptive integration of the technology in the support of the patient’s journey of successful management of musculoskeletal disease and improving the quality of life.

Summary/Conclusion Newer Manufacturing Process Process 3D printing Coatings

Advantage Customization, ability to use newer material Osseointegration, enhance osteo-induction, prevent infection

Newer Materials Material Tantalum Modified titanium PEEK PLA

Advantage Osseointegration, Osteo-incorporation Modulus of elasticity closure to the bone, relative MRI compatibility, and non-toxic High strength, toughness, and tissue biocompatibility Biodegradable, good tensile strength, and elastic modulus

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References 1. Rahyussalim AJ, Marsetio AF, Saleh I, Kurniawati T, Whulanza Y. The needs of current implant technology in orthopaedic prosthesis biomaterials application to reduce prosthesis failure rate. J Nanomater. 2016;2016:9. https://doi.org/10.1155/2016/5386924. 2. Markatos K, Tsoucalas G, Sgantzos M. Hallmarks in the history of orthopaedic implants for trauma and joint replacement. AMHA-Acta Medico-Historica Adriatica. 2016;14(1):161–76. 3. Brand RA. Sir William Arbuthnot Lane, 1856–1943. Clin Orthop Relat Res ®. 2009;467(8): 1939–43. 4. Paganias CG, Tsakotos GA, Koutsostathis SD, Macheras GA. Osseous integration in porous tantalum implants. Indian J Orthop. 2012;46:505–13. 5. D’Angelo F, Murena L, Campagnolo M, Zatti G, Cherubino P. Analysis of bone ingrowth on a tantalum cup. Indian J Orthop. 2008;42:275–8. 6. Bobyn JD, Toh KK, Hacking SA, Tanzer M, Krygier JJ. Tissue response to porous tantalum acetabular cups: a canine model. J Arthroplast. 1999;14:347–54. 7. Balla VK, Bodhak S, Bose S, Bandyopadhyay A. Porous tantalum structures for bone implants: fabrication, mechanical and in vitro biological properties. ActaBiomater. 2010;6(8):3349–59. https://doi.org/10.1016/j.actbio.2010.01.046. Epub 2010 Feb 2. PMID: 20132912; PMCID: PMC2883027. 8. Kurtz SM, Devine JN. PEEK biomaterials in trauma, orthopedic, and spinal implants. Biomaterials. 2007;28(32):4845–69. 9. Harting R, Barth M, Bührke T, Pfefferle RS, Petersen S. Functionalization of polyethetherketone for application in dentistry and orthopedics. BioNanoMaterials. 2017;18(1–2):20170003. https://doi.org/10.1515/bnm-2017-0003. 10. Haleem A, Javaid M, Vaish A, Vaishya R. Three-dimensional-printed polyether ether ketone implants for orthopedics. Indian J Orthop. 2019;53:377–9. 11. Wong KC. 3D-printed patient-specific applications in orthopedics. Orthop Res Rev. 2016;8:57. 12. Kirmanidou Y, Sidira M, Drosou ME, Bennani V, Bakopoulou A, Tsouknidas A, Michailidis N, Michalakis K. New Ti-alloys and surface modifications to improve the mechanical properties and the biological response to orthopedic and dental implants: a review. Biomed Res Int. 2016;2016:2908570. 13. Long M, Rack HJ. Titanium alloys in total joint replacement – a materials science perspective. Biomaterials. 1998;19(18):1621–39. 14. Kamrani S, Fleck C. Biodegradable magnesium alloys as temporary orthopaedic implants: a review. Biometals. 2019;32(2):185–93. 15. Williams DF. On the nature of biomaterials. Biomaterials. 2009;30:5897–909. 16. Brown BN, Ratner BD, Goodman SB, Amar S, Badylak SF. Macrophage polarization: an opportunity for improved outcomes in biomaterials and regenerative medicine. Biomaterials. 2012;33:3792–802. 17. Franz S, Rammelt S, Scharnweber D, Simon JC. Immune responses to implants–a review of the implications for the design of immunomodulatory biomaterials. Biomaterials. 2011;32: 6692–709. 18. Sridharan R, Cameron AR, Kelly DJ, Kearney CJ, O’Brien FJ. Biomaterial based modulation of macrophage polarization: a review and suggested design principles. Mater Today. 2015;18: 313–25. 19. Anderson JM, Rodriguez A, Chang DT. Foreign body reaction to biomaterials. Semin Immunol. 2008;20:86–100. 20. Langer R. I articles. Science. 1993;260:5110. 21. Im GI. Biomaterials in orthopaedics: the past and future with immune modulation. Biomater Res. 2020;24(1):7.

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22. Ni J, Ling H, Zhang S, Wang Z, Peng Z, Benyshek C, Zan R, Miri AK, Li Z, Zhang X, Lee J. Three-dimensional printing of metals for biomedical applications. Mater Today Bio. 2019;3: 100024. 23. Shah S, Bagaria V. 3D printing- creating a blueprint for the future of orthopedics: Current concept review and the road ahead!. J Clin Orthop Trauma. 2018;9(3):207–212. https://doi.org/ 10.1016/j.jcot.2018.07.007. 24. Leeuwenburgh SCG, Wolke JGC, Jansen JA, Jonge LT d. Organic-inorganic surface modifications for titanium implant surfaces. Pharm Res. 2008;25(10):2357–69. https://doi.org/10.1007/ s11095-008-9617-0. 25. Kulkarni M, Mazare A, Schmuki P, Iglic A, Seifalian A. Biomaterial surface modification of titanium and titanium alloys for medical applications. Nanomedicine. 2014;111:11. 26. Shahali H, Jaggessar A, Yarlagadda PK. Recent advances in manufacturing and surface modification of titanium orthopaedic applications. Procedia Eng. 2017;174:1067–76. 27. Jemat A, Ghazali MJ, Razali M, Otsuka Y. Surface modifications and their effects on titanium dental implants. Biomed Res Int. 2015;2015:791725. https://doi.org/10.1155/2015/791725. 28. Rautray TR, Narayanan R, Kwon TY, Kim KH. Surface modification of titanium and titanium alloys by ion implantation. J Biomed Mater Res B Appl Biomater. 2010;93B(2):581–91. https:// doi.org/10.1002/jbm.b.31596. 29. Braceras I, Alava JI, Oñate JI, Brizuela M, Garcia-Luis A, Garagorri N, de Maeztu MA. Improved osseointegration in ion implantation-treated dental implants. Surf Coat Technol. 2002;158:28–32. https://doi.org/10.1016/S0257-8972(02)00203-7. 30. Huang N, Yang P, Leng YX, Wang J, Sun H, Chen JY, Wan GJ. Surface modification of biomaterials by plasma immersion ion implantation. Surf Coat Technol. 2004;186(1):218–26. https://doi.org/10.1016/j.surfcoat.2004.04.041.

Part II Principles of Orthopaedic Nailing

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General Principles of Intramedullary Nailing for Long Bone Fractures M. Shantharam Shetty

Contents Hollow Nails Versus Solid Nails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

Abstract

Nailing of fractures of long bones is the mainstay of management today and perhaps will continue to be so. Though the basic general principles of nailing has remained the same from 1940s it has evolved to a considerable extent and the mechanical and biological aspects of bone healing is taken more into consideration. The entry points, the reaming, the length and width of the nail, to lock or not to lock and how to lock, the material used and more than all the importance of soft tissue encompassing the fracture are considered and debated. In short, we have dealt all these aspects and finally what counts is the final outcome of a good nailing, where the general principles are taken into account. Keywords

Nail · Characteristics · Principles · Length · Width · Reaming · Locking

Ever since the great visionary Gerhard Kuntschner (Fig. 1) scientifically evolved and presented to the world the concept of intramedullary nailing, much water has indeed flown both under and over the bridges. From the original Kuntschner nail (Fig. 2), various types of nails have evolved for fixing every single long bone, facilitating the comfort of the patient and the surgeons alike. The tibial and femoral nails have evolved (Fig. 3) much more than humeral and the forearm nails [3] mainly because of the challenges of increased high-velocity M. S. Shetty (*) NITTE University, Tejasvini Hospital, Mangalore, Karnataka, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_8

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Fig. 1 Gerhard Küntscher (1900–1972)

injuries, because of significant soft tissue injuries, unstable fractures patterns, open and polytrauma situations, and sometimes inability to maintain reduction, more than all the difference between their anatomy of the shape, the curves, and width of medullary cavity, specially between Asians, Caucasians, and perhaps even Africans and also between males and females. For the fractures of the upper limb long bones, the humerus (Fig. 4a–d), and specially both bones of the forearm (Fig. 5), satisfactory nail is still not in vogue. This is not mainly because of the shape of these bones, the narrowness of the medullary cavity, entry-point controversy, and the complexity of the shoulder and elbow and wrist joints. The shoulder is an unstable ball and socket joints, the elbow is a hinge joint, the superior radial nerve joint with the head of the radius articulating with capitellum is a pivot joint, and the wrist with the inferior radial nerve joint is a complex gliding joint. With the age expectancy of the population of different countries of the world increasing year by year, geriatric hip fractures have considerably increased. The use of intramedullary nailing is the mainstay of these fractures and thereby various modifications, designs have came into vogue to suit the osteoporotic nature and comminuted pattern of these fractures (Fig. 6a–g). The basic principles of the length of the nail, the breadth of the nail when to ream and when not to ream, and static locking of the nail have fairly been standardized today [1, 2]. But nailing of any long bone fracture should not be taken as a magic wand. The great Latin words of “primum non nocere” perhaps fit in with every nailing which is

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Fig. 2 Kunstscher nail for shaft of femur

Fig. 3 Expert tibial nail

undertaken. The treating surgeon should be convinced of the absolute indication of the procedure and should look into the fracture pattern, the fracture extension into the articular surface, the narrowness or deformation of the medullary canal, the possibility of pathological fractures, and the surgical resources and skill he has in difficult unwarranted situations.

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Fig. 4 Antigrade nail humerus for gunshot injury shaft humerus: (a) retrograde humeral nail; (b) humeral nail set

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Fig. 5 Intramedullary nailing of both bones forearm

The treating surgeon should also understand why an intramedullary nail fails. Apart from comorbid conditions like smoking, the noncompliance, the fracture personality is usually blamed for the support of the failed nailing. The surgeon should be aware that once the fracture fails to unite, the internal fixation device used will fail and may even bend or break. Thereby an early action is necessary to prevent the disaster of a nail breakage or bending. Biomechanically, interlocking nails act as splints internally that share the loads like compressive, tensional, torsional, and even bending forces (Fig. 7). The stability of any nail depends on [3]: 1. Nail characteristics. 2. The coronal section, the diameters, and nail shape.

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Fig. 6 Different types of I M nails in use today

3. The nail ends and the working length will have to be taken into consideration. 4. Reamed or unreamed. 5. Pattern of fracture and the quality of bone. The stability of the nail construct also depends on: 1. Material prospects of the metal used. 2. Cross-section and shape, diameters of curves (Fig. 8a and b). The usual materials used for the interlocking nails are an alloy of titanium or stainless steel 316 L. 316 L SS steel has double the modulus elasticity of cortical bone, and the alloy of titanium has elastic modulus close to the cortical bone. The ability to resist any tension is the modulus. The interlocking screws usually bend or break, when the nail does not have a cortical contact, thereby the interlocking screws take the compressive load and break.

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Fig. 7 Characteristics of the nail

Fig. 8 Cross section of the nail

Typically nail or screws break because principles of fixation have not been taken into consideration (Fig. 9a–c), and it is to be noted that the nail’s diameter is directly proportional to its bending rigidity.

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Fig. 9 (a) Broken nail; (b) bent nail; and (c) broken screws

Hollow Nails Versus Solid Nails Efficiency • A hollow nail is more efficient as less material can be used for equivalent values of bending and torsional rigidity [1, 2]. Bending Stiffness [1–3] • The cylindrical cross-section of the nail directs the stiffness in bending which is directly related to the fourth power of its radius. • In the case of a hollow cylinder, the bending stiffness is proportional to the fourth power of the outer radius minus the fourth power of the inner radius. • The solid cylinder is more stiff than a hollow cylinder, when it is of the same diameter. • However, the material volume used in the making of an IM nail of fixed length, then the use of a nail which is hollow will allow outer radius to be used which is greater, results in a nail which is stiffer.

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• A Synthes 13 mm nail (6.5 mm radius) has a 1.2 mm wall thickness. D ¼ 6.5 mm, D1 ¼ 5.3 mm (which is 6.5 – 1.2). So (D4 – D14) ¼ 1785 – 789 ¼ 996. Torsional Rigidity • The rigidity of torsion of the nail increases by a factor of 16 when the radius of the nail is doubled. Working Length of a Nail • Working length is defined as the length of a nail spanning the fracture site from its distal point of fixation in the proximal fragment to its proximal point of fixation in the distal fragment. • It is calculated by the length between the two points on each of the sides of the fracture where the metal firmly grips the bone. • Thereby the majority of the load across the fracture site is the unsupported portion of the nail between the two major bone fragments. • The bending rigidity of a nail is inversely proportional to the square of its working length. • Torsional rigidity is inversely proportional to a nail’s working length. • For a strong fixation with a shorter working length, the bending and torsional rigidity of the nail should be taken into consideration. • The nail and its working length can vary depending on: a) Bending and torsion force. When the bone bends at the fracture site, the nail may become fixed to the bone by 3-point fixation. b) Type of fracture (fracture pattern) and if the fracture is reduced. c) Interlocking. This modifies the working length of a nail and increases torsional stability. d) Reaming. This prepares a uniform canal, allows a larger diameter nail to be used, improves nail/bone fixation, and reduces the working length of the nail.

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• A nail has a shorter working length in bending with fixation of a transverse fracture than when used to stabilize a comminuted fracture. Thereby in a circular nail that is solid, the rigidity of bending is equal to the third power of the diameter of the nail. Whereas, it is equal to the fourth power of the diameter when there is a torsional force. When inserting a nail, the axial force generates a circumferential stress expansion in the bone which is called the hoop stress. That is why when inserting a nail, one should not use great force which can result in higher hoop stress which can shatter the bone and should be avoided at all costs. It is also better to over-ream the entry hole at least posteriorly by a millimeter which will reduce the hoop stress. The working length of the nail and the total length of the nail will also have to be taken into consideration (Fig. 10). The number and location of the interlocking screw has an important bearing on fracture healing. Multiplanar location of the screws in multiple planes can reduce minor movements (Fig. 11). And it is also important to note that if you place the distal locking screws very close to the fracture site, it will result in less contact of the nail being less to the cortex, thereby it will have definitive stress on the locking screws. Reaming: Biomechanically, when you ream further by 1 mm, the contact area of the nail to the bone surface increases by approximately 38%, thereby it increases all-round stability and the working length is reduced [4]. It is proved beyond doubt that biomechanically reamed nails provide firmer fixation than the unreamed ones (Figs. 12 and 13).

Fig. 10 The working length and anatomical length of the nail

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Fig. 11 Multiplanar locking nails from the AO Research

Fig. 12 Double segmental fracture femur treated with femoral locking nail second generation

Fig. 13 Short and long PFN for intertrochanteric fractures femur

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Fig. 14 Multiloc nail done for fracture-dislocation shoulder

In the upper limb long bone fractures, biomechanically and anatomically a nail is a poor fixation bringing about more bending and torsional stress and entry-point problems. However, the newer multiloc nail for fractures of humerus both the upper end and shaft of the humerus are showing better results because of the changed entry point and the multiplanar and multiloc configuration of locking screws (Fig. 14). In short, locked intramedullary nails specially for fractures of femur and tibia are a boon to the surgeons’ armamentarium in treating the fractures of these bones (Fig. 12). However, newer designs of nails for the long bones of the upper limb are emerging with modifications of the older ones. But, proper knowledge of the nail used, its biomechanical properties, and the reduction techniques is quite essential for a successful outcome. The gratification of the patient after a properly done intramedullary nailing far outweighs any other method of fixation of a long bone specially of the lower limb.

Bibliography 1. AO Foundation Surgery Reference. surgeryreference.aofoundation.org. AO Surgery Reference is a resource for the management of fractures, based on current clinical principles, practices and available evidence. 2. Books and e-books – AO Trauma – AO Foundation. aotrauma.aofoundation.org/journals-andpublications/books-and-e. As with the recently published Manual of Fracture Management. 3. Orthopaedic Surgery | AO Manual of Fracture Management. www.thieme.com/books-main/ orthopaedic-surgery/product/32. AO Manual of Fracture Management: internal fixators. Concepts and cases using LCP/LISS. item-3246-pubid-1591800761. 4. Tanna’s Interlocking Nailing, 4th Edition. D.D Tanna et al.

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Evolution of Intramedullary Nails for Long Bone Fractures in the Upper Limb Shailesh Pai and Muthur Ajith Kumar

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nailing for Humerus Shaft Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evolution of Nail Designs for Humeral Shaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nailing in Proximal Humerus Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nailing in Forearm Shaft Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Nailing in fractures of the upper limb has evolved a long way, but has not paralleled the impact it has made in fractures of the lower limb. This chapter describes the evolution of the nails that are used to treat fractures in upper limb bones and systematically describes the pros and cons of each device. Keywords

Intramedullary nails · Upper limb · Evolution

Introduction Intramedullary interlocking nailing is considered the gold standard for the treatment of long bone fractures, especially in the lower limb. The success of this technique in treating diaphyseal fractures has made the surgeons extend the indications to include even metaphyseal and some partial articular fractures too. “As the Surgeon’s experience increases, the range of indications will be widened.” This statement is S. Pai Tejasvini Hospital, Mangalore, India M. A. Kumar (*) Department of Orthopaedics and Trauma, Tejasvini Hospital, Mangalore, Karnataka, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_10

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attributed to Richard Maatz, who wrote this on a hospital ship in the Mediterranean in 1945 [1]. This was published in the famous book “Die Technik der Marknagelung” [“The Technique of Intramedullary Nailing”] by Gerhard Kuntscher. Strangely though, in cases of fractures of long bones in the upper limbs, nailing is not considered as the gold standard by most trauma surgeons around the world. Similar results are not replicable in upper limb bones primarily due to the narrow medullary canals as well as the fact that plating in these bones is giving excellent outcomes. Also, the fact that these bones are not “weight-bearing”, the concept of load-sharing devices that are associated with the intramedullary nail is not applicable. To understand the applicability and evolution of the nails used in upper limbs, it would be prudent to divide them into regional subheadings like proximal humerus, shaft humerus, distal humerus, and forearm shaft. Nails are not used for distal humerus intra-articular fractures and hence only the other three regions will be dealt with in this chapter.

Nailing for Humerus Shaft Fractures Intramedullary interlocking nailing for humeral shaft fractures is the first line of treatment in very few centres across the globe. The choice of nailing as a treatment option is met with scepticism. This is chiefly attributed to the fact that open reduction with plate osteosynthesis is considered safe, reproducible, effective treatment and has an advantage of mostly being done without radiation exposure intraoperatively. The problems associated with nailing humeral fractures were multifactorial. 1. Entry either antegrade or retrograde is required to open the adjacent joint more often than not and this itself deemed it unnecessary, especially in open fractures or patients with diabetes for risk of septic arthritis. 2. Reaming the canal was difficult especially in thin-built individuals especially in short-statured Asian females, and hence, snug fit of the nail was not possible, leading to mechanical shortcomings. 3. Humerus is subjected to extreme torsional forces due to high rotational movements of the shoulder and uniaxial movement of the elbow, and it is proved biomechanically that nails do not tolerate torsional forces well often leading to its failure. 4. Antegrade entry point is required to enter through the sulcus where the footprint of the rotator cuff lies. This often led to inadvertent damage to the cuff either during insertion or due to the implant per se if it was proud proximally even by 2 mm (Fig. 1). 5. Retrograde entry would sometimes lead to fracture at the entry site, especially in narrow canal patients, which would be disastrous (Fig. 2). 6. Humerus does not tolerate distraction, and hence, if the fracture was fixed in distraction it would definitely lead to non-union which was usually the case with older generation nails in which the intraoperative compression device was non-existent (Fig. 3).

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Fig. 1 (a) Radiograph showing the “proud” humerus nail which will irritate the rotator cuff. (b) Anatomy picture of rotator cuff

7. With the radial nerve in close proximity to the bone especially in the middle third, any fracture in this area which is the most common site of fracture in the humerus shaft, any inadvertent passage of the nail or guide wire posteriorly outside the canal could lead to neuropraxia. This along with impingement of the nerve at the fracture site or in the callus (as union with nailing is with secondary healing) could also be the cause for radial nerve palsy postoperatively. Due to all these issues, nailing took a back seat and plating is considered the gold standard in treating these fractures as most of these issues are unique to nailing and not seen with plating. But with better understanding of these complications and with newer designs, most of these problems were countered, and nailing today has provided an efficient strategy to treat these injuries.

Evolution of Nail Designs for Humeral Shaft The first surgeon to design an intramedullary nail for the humerus and then publish its results on a large series of patients was the visionary, Gerhard Kuntscher [2]. This was a non-locking nail and hence did not gain much popularity. Similar non-locked nails like Ender’s nail, rush nail were used for treating humeral shaft fractures at various centres. There were many complications chiefly attributable to non-locking aspect namely the proximal migration of implant leading to prominent hardware and its mechanical problems. Also, the lower torsional stiffness lead on to delayed union and non-union. Hence, the current indications for use of these nails are restricted to pediatric fractures. Sidel was the first to develop an interlocking nail which was introduced in the 1980s, and it was a reamed nail [3]. The canal was reamed up to 10 mm and a 9 mm nail was inserted antegrade with proximal locking and distal locking was by a unique spreading mechanism. This too ran out of favour as there were reports of rotator cuff damage during reaming and the distal locking mechanism did not work in many cases. Due to all these factors, standard intramedullary

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Fig. 2 Fracture at the entry point of the retrograde humeral nail

interlocking nails akin to femoral nails were introduced (Fig. 4). These too were modified to second-generation nails with multiangular locking options or a spiral blade design for better purchase options, especially in proximal humerus. The biggest problem with antegrade humeral nailing was injury to the rotator cuff, thereby leading to painful and decreased shoulder range of movements leading to an unsatisfied patient functionally. Hence, a retrograde nailing technique was developed, and these nails were inserted in retrograde fashion, minimizing shoulderrelated complications (Fig. 5). But this technique had its own set of complications like iatrogenic distal humerus fractures especially if due care was not taken to create a trough for insertion of the awl/nail at the entry point. The current designs of nails have evolved to provide better torsional stability by incorporating multiangular locking bolts. This is expected to withstand the significant torsional forces that are existent in the humeral shaft (Fig. 6).

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Fig. 3 Radiograph showing the distraction at the fracture site

Advantages of nailing over other devices in humerus shaft fractures 1. Biological implant considering that the fracture site does not require to be exposed, and in most cases, it is done with closed reduction techniques. 2. Multiangular locking bolts provide enough stability to withstand torsional forces. 3. Able to span nearly the entire length of the bone which is useful, especially in osteoporotic fractures, thereby providing some mechanical support to the implanted humerus in these patients who are prone to frequent falls. 4. Peri-implant fracture is extremely rare as compared to plate fixation. The plate increases the stresses at its ends and could lead to fractures. Fracture incidence is also higher after implant removal of a plate versus a nail. 5. Smaller incisions are definitely cosmetically superior as compared to open plating scars. 6. Implant of choice in pathological fractures as the entire bone span will be bridged.

Nailing in Proximal Humerus Fractures Nailing as a treatment option for proximal humerus fractures has evolved a long way considering that it was not even one of the treatment choices considered for these injuries about a couple of decades ago. Nailing was carried out in Neer’s 2-part

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Fig. 4 Standard intramedullary interlocking nail of humerus

fracture that too only in centres which were “avid nailers”. The modification of the universal nail to provide an option for a spiral blade (Fig. 7) in the proximal part resulted in it being considered in many centres as an option for 2-part fracture humerus since it provided better rotational stability. But this nail design did not provide reliable fixation options in more complex 3and 4-part fractures. Hence, other nail designs which had multiple proximal bolts in different angles (multiangular) were designed and were favoured. These included Polarus, T2, or the Targon-nail which had three-dimensional locking properties proximally (Fig. 8). Good to excellent outcomes were reported with the use of these so-called “Christmas tree” nails [4–7], since the top of nail with the screws looks like a Christmas tree. The issues facing the use of these nails were (a) Rotator cuff problems due to insertion of instruments or nail, reaming which caused part of the rotator cuff footprint to be damaged leading to chronic pain. (b) Tuberosities repositioning was tough as the nail would be seated exactly at the location where the greater tuberosity (GT) should be relocated. This would lead

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Fig. 5 Retrograde humeral nailing

to lateralizing the reduction of GT which would impede functional outcome (Fig. 9). (c) Varus malreduction would be a concern since the nail entry would be from a lateral point with respect to the anatomical axis of the humerus (Fig. 10). (d) The bolts which were to be inserted through the nail often led to splintering of the GT fragment as more often than not these fragments are very thin and friable. These factors were considered, and the next generation of nails was designed. The MULTILOCTM nail (Fig. 11) is a straight nail design with its entry medial to the sulcus through the articular cartilage (Fig. 12). The entry being in line with the anatomical axis prevented not only the damage to the rotator cuff but also varus

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Fig. 6 Radiograph of a multiloc nail used for fracture mid-shaft humerus

malreductions. Also, the repositioning of the GT fragment to its anatomical location was easier considering that the nail occupied a position very medial. The bolts of this newer generation nail were conically tapered due to which the stress distribution would be more uniform and on a wider area thus preventing point-forces on the flimsy GT fragment thereby preventing its splintering. Other unique features of the nail: 1. The option of the calcar screw, also called the “kick stand” or the C-screw, is present in the nail. This is the same concept of the calcar screw which is present in the PHILOS plate. The screw is at a trajectory of 135 to the long axis of the nail and is inserted into the inferomedial calcar region. 2. The locking bolts of the proximal nail have a built-in hole to accommodate one more locking screw (3.5 mm) which locks into the bolt. This “screw-in-screw” configuration increases the cut-out resistance. The locking screw goes outside the nail at is inserted into the posterior aspect of the humeral head where there is a better bone stock (Figs. 13 and 14). 3. The bolts also have small holes to enable the GT and LT to be pulled to its position using sutures (similar to the holes in the PHILOS plate).

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Fig. 7 Spiral blade option in a humeral nail

4. The bolts hole in the nail is in line with polyethylene bushing which imparts additional stability to the bolts and resists cut-out forces. The unique features of this nail have aided the surgeons to extend the indications and use it in all types of proximal humerus fractures that are 2, 3, and 4-part fractures (Figs. 15 and 16) and even those which are associated with dislocation either anterior or posterior. The multiangular locking bolts in the proximal segment aids to secure the GT and LT properly, and the biomechanical advantages of the nail over a plate have yielded superior outcomes as evidenced by recent literature [8, 9]. Advantages of the MULTILOC nail over other devices in proximal humerus fractures

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Fig. 8 Schematic representation of the Polarus nail (on left) and the T2 Targon nail (on right)

1. Shorter lever-arm and hence better cut-out resistance as compared to a plate. 2. No issues with regards to the presence of medial comminution which is present in about 60% of the fractures, especially in the young. In the presence of medial comminution, isolated PHILOs plating is more prone to failure and often requires either augmentation plating on the medial side or an intramedullary fibula strut graft. 3. Due to the wider arc of the trajectory of screws, increased cut-out resistance. Also, the screw in screw configuration adds on to the stability. 4. As there is no chance of secondary collapse postoperatively, the bolts could be inserted up to the sub-chondral bone unlike a plate in which 8 mm short of the sub-chondral surface is recommended. 5. Better implant anchorage due to the anchorage though the entry point in the humeral head which has a strong bone. This is the concept of “proximal anchoring point” [10]. 6. No incidence of screw back-out even when tested with supra-physiological forces in labs [10]. 7. No incidence of secondary displacement of the fixed construct which occurs in almost all cases of fixation with a plate.

Nailing in Forearm Shaft Fractures Fractures of the shaft of the forearm were always considered intra-articular fractures considering that the inter-osseous membrane was attached to the entire length of the radius and ulna shaft (Fig. 17). This membrane was important for pronation-

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Fig. 9 Malpositioning of GT due to the nail impeding its anatomical reduction

supination movements and unless the proper length of both the bones was achieved, these movements were restricted. Also due to the complex nature of the radius in which the radius is bent not only in the antero posterior plane but also in the medio-lateral plane, inserting a straight nail into the curved bone was considered an issue causing relative lengthening of the straightened-out radius with respect to ulna. Hence, nailing for these fractures were not recommended, and it was only reserved in pediatric fractures and in those fractures where the soft tissue prevented plating of these injuries. On the other hand, ulna being a relatively straight bone, nailing was considered by a few surgeons as preferable. But the

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Fig. 10 Varus malreduction due to the lateral entry of the nail

narrow dimensions of these bones prevented interlocking options, and hence these non-locked nails seldom provided the rotational stability that is required for optimal healing of these bones. Unlike the other long bones like humerus shaft, femur shaft, and tibia shaft, malunion of even minimal degree of angulation is unacceptable in forearm fractures as it would lead to loss of pronation and supination and hence it was recommended for anatomical reduction and stable fixation of these bones to prevent malunion that might occur as a result of non-locked nails. Isolated ulna shaft injuries were considered good indication for nailing since the intact radius would provide additional stability. But there were few complications associated with the entry point of the nail. If the nail is left sticking proud, outside the bone, it could lead to olecranon

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Fig. 11 The MULTILOCTM nail

Fig. 12 Schematic representation of the entry point for the MULTILOCTM nail

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Fig. 13 The locking bolt showing the hole for the screw in screw configuration and also the holes for passing the sutures to secure the GT and LT

Fig. 14 The screw in screw configuration on the left and the diagram showing the position of the locked screw outside the nail and reaching the posterior area

bursitis or even sloughing out of the overlying skin in extreme cases. On the other hand, isolated radius shaft fractures are more unstable and not considered suitable for intramedullary nailing. Various nails like the square nail, enders nail, rush nail, TENS have been used for fixation of these fractures with variable outcomes (Figs. 18 and 19). Of late, even interlocking nails have been designed for their use with various multiangular locking options (Fig. 20). But the results of these are considered moderate at best and are not the preferred modality of treatment across the globe. The literature is sporadic, and plating is still considered the gold standard for treatment of these injuries and at this point all that could be noted is that the nails have a long journey to undertake to be considered as a primary treatment option for fractures in the forearm shaft.

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Fig. 15 Case example of a 39-year-old patient with 3-part fracture proximal humerus treated by a MULTILOC nail

Fig. 16 Case example of a 42-year-old patient with 4-part fracture proximal humerus treated by a MULTILOC nail

172 Fig. 17 Schematic representation of the forearm bones with inter-osseous membrane

Fig. 18 Fracture forearm shaft fixed with square nails

S. Pai and M. A. Kumar

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Fig. 19 Fracture forearm shaft fixed with rush nails Fig. 20 Fracture forearm shaft fixed with interlocking nails

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References 1. Gradl G. Focus on upper extremity nailing – risk or benefit? Injury. 2016;47(Suppl 7):S1–2. 2. Küntscher G. Praxis der Marknagelung. Stuttgart: Schattauer; 1962. 3. Varley GW. The Seidel locking humeral nail: the Nottingham experience. Injury. 1995;26(3): 155–7. 4. Gradl G, et al. Angular and sliding stable antegrade nailing (Targon PH) for the treatment of proximal humeral fractures. Arch Orthop Trauma Surg. 2007;127:937–44. 5. Stedtfeld HM, Mittlmeier T. Fixation of proximal humeral fractures with an intramedullary nail: tips and tricks. Eur J Trauma Emerg Surg. 2007;33:367–74. 6. Mathews J, Lobenhoffer P. Marknagelunginstabilerproximaler Humerusfrakturen. Oper Orthop Traumatol. 2007;19:255–75. 7. Lin J. Effectiveness of locked nailing for displaced three-part proximal humeral fractures. J Trauma. 2006;61:363–74. 8. Hessmann MH, et al. Internal fixation of fractures of the proximal humerus with the Multiloc Nail. Oper Orthop Traumatol. 2012;24:418–31. 9. Hao TD, Huat AW. Surgical technique and early outcomes of intramedullary nailing of displaced proximal humeral fractures in an Asian population using a contemporary straight nail design. J Orthop Surg. 2017;25(2) 2309499017713934 10. Euler SA, Petri M, Venderley MB, Dornan GJ, Schmoelz W, Turnbull TL, Plecko M, Kralinger FS, Millett PJ. Biomechanical evaluation of straight antegrade nailing in proximal humeral fractures: the rationale of the “proximal anchoring point”. Int Orthop. 2017;41(9):1715–21.

Evolution of Intramedullary Nails for Long Bone Fractures in the Lower Limb

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M. Shantharam Shetty and K. Yogesh

Contents History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics: Evaluation and Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Locking of Intramedullary Nails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Slotted Versus Non-slotted Nails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Titanium Alloy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Latest Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximal Femoral Nail (PFN) Anti-Rotation A2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Intramedullary nails have been the most commonly used and more stable implants especially in the lower limb long bone fractures. It is paramount to know the biomechanical aspects of the implant for a good functional outcome. In this chapter, we discuss the history, various biomechanical properties of intramedullary nails, and the know-how of modern implants. Any nail, however, should not only be biocompatible but should overcome all stresses at the fracture site. Keywords

Küntscher · Cross-section · Reaming · Working length · Locking · Length of the nail · Static and dynamic

M. S. Shetty NITTE University, Tejasvini Hospital, Mangalore, Karnataka, India K. Yogesh (*) Tejasvini Hospital, Mangalore, Karnataka, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_9

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History One of the methods of managing the fractures way back in 1870 by Bérenger Féraud was to use ivory pegs! Later in the Victorian era, ivory pegs were used in fracture treatment even as an intramedullary tool (Fig. 1) [2]. Later Nicolas Senn of Chicago used tubular splints made from the bones of a cow. A system of operative surgery [3] by Burghard in 1914 mentions screws, nails, and pegs made of steel and Bellevue Hospital in New York used aluminium splints. Later in 1937 [5] Rush et al. used stainless steel wires to stabilize broken bones. Method continued and further developed by the Ender School in Vienna and even in the modern era Rush nails are used in treating fractures of children. In 1938, Robert Danis of Brussels used intramedullary implants in different types of fractures – implants made of steel. There was a revolution in 1940 by Gerhard Küntscher of Kiel when he introduced intramedullary nails and emphasized the entry points away from the fracture without opening the site of the fracture and stressed the importance of metal used, the cross-section of the nail, and the nail extending to the full length of the medullary canal. He reported his success in 13 cases at the German Surgical Society meeting in 1940 which caught the imagination of surgeons around the world.

Fig. 1 Pegs inserted into the medullary canal in 1870

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Biomechanics: Evaluation and Challenges The great designs, material selection, and functional simplicity of the current intramedullary devices came into being with extensive research on the concepts of biomechanical laws and their understanding. Going through the literature, Nicolaysen [3, 4] contributed immensely to the importance of the length and circumference of the implant in maintaining the stability of the fracture. Hey Grooves [1, 5–7] claimed in his publications later that solid nails were better than hollow nails which proved contradictory later. Smith Peterson in the 1950s (Fig. 2) brought in the concept of triflanged nails for fixing fractures of the neck of femur. In 1932, Sven Johnson introduced the cannulated feature into this nail and Lawson Thornton attached a side plate with these nails to give more rotational stability. Corrosion of metal was a problem in these nails, thereby failure of fractures and complications because of electrochemical reaction which was later corrected by the introduction of Vitallium, a cobalt base alloy. Vitallium was used extensively though it had much less strength. However, with the 18.8 stainless steel coming in with its better resistance to corrosion, it stood the test of time. The advances made in the field of antiseptic surgery, microbiology, and antibiotics made the advancement of orthopaedic surgery with implants much easier and with fewer complications. After the Küntscher cloverleaf design, various modifications in the cross-section, its length, the shape, and the metal used evolved (Fig. 3). Till the 1940s, the technique of intramedullary nails could not catch up with the imagination of the surgeon mainly because of the lack of understanding of biomechanics and callus formation, thereby the healing of the fracture. The loading experiments of the implant on the bone could not be perfectionized and the experiments are continued even today.

Fig. 2 The cross-section of intramedullary nails year-wise

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Fig. 3 Different intramedullary designs with cloverleaf and V-shaped cross-sections

The credit for introducing reamers to ream the medullary canal goes to Fischer [8] in 1950. G. Küntscher, a great innovator, innovated and guided flexible reamers which got widespread acceptance from the surgeon community. This method enhanced the possibility of tight-fitting nails so that there would be rotational stability. Smith et al., [10] in their experiments, proved that by tight-fitting nails the contact area of the nail increased by nearly 38%, thereby the rigidity of the nail increased and the torsional bending force controlled. However, what is paramount is the good reduction of the fracture.

Locking of Intramedullary Nails Intramedullary nails with good nail-bone contact, no doubt, brought good results especially in transverse and short oblique fractures, but in comminuted fractures or fractures with bone loss and the proximal and upper 1/3 fractures, the stability was at stake resulting in delayed or non-union [12, 16] and even shortening because of the collapse of fragments and even implant protrusion occurred. To control this, in 1953 Modny and Bambara [9] introduced the concept of locking the nail so that collapse or rotational instability at the fracture site will not occur. Klaus Klemm in 1960 introduced the mediolateral and later anteroposterior holes in the nail for locking with screws. The second-generation nails were introduced with newer methods of placement of locking screws. However, the working length of the nail which is measured by

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Fig. 4 Working length

calculating the distance between the bottom and the top position and maintaining the working length of the nail is important to maintain the load across the fracture site. The shorter the working length, the better would be stability. Once the biomechanical principles of the nailing of the long bones were understood well, the newer designs were designed for the betterment of the healing of the fracture (Fig. 4).

Slotted Versus Non-slotted Nails Gimeno et al. in the 1980s reported that alteration in the thickness of the material of the nail resulted in breakage [11] Stedtfeld [13] in his studies emphasized that the thinner walls of the intramedullary nails may lead to stronger bending loads resulting in deformation and also the curvature of the bone specially like the femur can cause deformation of the nail during implantation. However, loop stress which occurs at the time of insertion of the nail was an added factor even in non-slotted nails (Fig. 5). Russel Taylor in 1986 introduced the large diameter non-slotted nail which was possible because of the gun drilling machine technique, with better rotational stabilization. In the early 1990s from non-slotted cannulated solid nails [21] came into being.

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Fig. 5 Slotted: Flexibility and bending strength increased. Non-slotted: Torsional stiffness is increased

Dynamization Reaming, no doubt, brought about bone implant stiffness and most of the load carried by the nail, but a shielding of the stress and strain stimulus was necessary because of rigidity caused by interlocking screws fixed in the static mode. Thereby many delayed and non-union entered [11]. So, Grosse and Kempf thoughtfully brought in the concept of dynamization by delayed removal of screws at one end of the nail-bone construct. This also leads to the inclusion of a longitudinal oval hole called the dynamic locking hole which also prevented a secondary procedure within six to eight weeks bringing sometimes undesirable results and a burden economically on the health care system as well. This locking mode also brought about an increase in load at the fracture site bringing about better healing [12, 18]. Controversies cropped up with the reamed and non-reamed techniques. Though it was accepted that in open fractures, undreamed nails are the choice, the damage of

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too much of reaming results in thinning of cortical wall and the endosteal blood supply. So, limited reaming techniques were recommended with reamer increments only to 0.5 mm till the acceptable diameter is achieved. So, a well-fitting smaller nail diameter without damaging the blood supply and pressuring the strength of the cortical wall was accepted for better healing [11, 13, 20]. Thereby it was a race between stresses and the healing of bone. But what we should understand is that the nail which is a load-sharing device will initially bear most of the load, but as the fracture heals as Young’s modulus increases most of the load gets transferred to the fracture site bringing about micro-moments inducing better callus formulation.

Titanium Alloy In the field of material development in 1990 titanium was introduced as an alternative to medical-grade stainless steel (AISI 136 LUM ASTM F 138). Titanium was found to be less stiff and hence avoided nail breakage and non-union of fractures. Another advantage of titanium is that it shows less magnetic imaging and biocompatible interference than stainless steel implants.

Latest Developments For any fracture to heal, not only the biology but also mechanical stability and the stimulus at the fracture site are important. That is why the intramedullary nails are constantly improved to bring down the healing time and maintain the quality of the callus. Both titanium and stainless steel have variable young’s modulus, thereby shielding the bone from stress. Many authors [14] experimented on different biomaterials like resorbable reinforced composites, magnesium alloy, and memoryshaped alloys. Yet another reinforced composite material is the polymethyl methacrylate medullary nail. These have shown proven positive results. Even in osteoporotic fractures, biodegradable Mg-Na-Zn-Zr nails with the delivery of magnesium products and zoledronic acid in a stipulated manner. Nitinol-based materials with proven biocompatibility have also come in. What is more interesting is transcutaneous induction heating stimulus to bring about the dynamization of nails have also emerged. However, in spite of the welcome results with the proven biomaterials, intramedullary nails of either titanium or stainless steel are preferred the world over because of durability, compatibility, and related toughness. Another area of research was in the nail-screw interface and various modifications like means to increase angular stability, angular locking system (ASLS) which brings about nail-screw tight fit with different screw diameters as shown in Fig. 6. This aims at selective stress shielding which favours healing by controlling bending torsion. This brought about the Flexible Axial Stimulation (FAST) concept providing axial interfragmentary motion. But with all these developments in the last two decades,

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Fig. 6 Angular Stable Locking System

the full potentialities of intramedullary nails are yet to be explored for the benefit of patients. Further, research should bring about an ideal mechanical and biological environment for good healing of fractures [13]. Perhaps computational techniques with finite stimulation coupled with a robust passively powered wireless system may improve the nailing system. These innovations are likely to help early detection of likely non-union and thereby intervene soon for the benefit of the patient. Further, research also is going on as to how to prevent implant-related infections through local delivery of antibiotics and even controlled release of bone morphogenic proteins and other osteoinductive growth factors for the healing of fractures. Some of the modifications of nails related to bone morphology and stature of patients have also been introduced.

Proximal Femoral Nail (PFN) Anti-Rotation A2 It is well known that the Asian subcontinent people have smaller stature. To suit their stature and anatomy Proximal Femoral Nail (PFA) A2 has been introduced which has a lateral flattened cross-section which facilitates easy insertion. It also has a mediolateral angle of 5 which also eases the insertion of the nail at the tip of the greater trochanter. PFN A2 also allows either static or dynamic locking via the aiming arm. This option with dynamization is provided in the short, medium, and long PFN A2 Nails. Moreover, it has a single spiral blade which compacts the cancellous bone and anchors it, thereby controlling or preventing rotation and varus collapse. Even the cut-out resistance has been proven to be better in PFN A2. PFNA has been found to be well-suited for pertrochanteric, intertrochanteric, and even high subtrochanteric fractures. However, it is not indicated in low subtrochanteric or femoral shaft or isolated fractures of the femoral neck. The original PFNA has two screws proximally with 8 mm screws distally and 6 mm proximally had a higher rate of failures specially screw cut-out and varus collapse (Fig. 7). Static or dynamic locking can be performed via the aiming arm with PFNA-II standard, small, and long. The PFNA-II long additionally allows for secondary dynamization (Fig. 8). Titanium Trochanteric Fixation Nail (TFN) system which has come into vogue lately permits an intramedullary approach for fractures of the femur. This system is made of titanium and has a full complement of cannulated helical blades, cannulated

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Fig. 7 PFNA-II short nail

Fig. 8 Different modes of distal locking

femoral neck screws, and cannulated nail series with end caps and locking screws and bolts. The use of 11.0 new helical blade compared to a single screw provides better cut-out and results in better rotational control especially of the medial fracture

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segment. A helical blade thereby has been developed to be a better device, especially in osteoporotic fractures. The cross-sectional area of the helical blade has been focused to be 38% of the lag screw, thereby reducing the bone chewing in the femoral neck and head. It has also been found to have a longer fatigue life (Fig. 9). The TFN is indicated in stable and unstable per- and intertrochanteric fractures, in basal neck fractures, and even in subtrochanteric fractures and ipsilateral trochanteric and femoral shaft fractures (Fig. 10). Fig. 9 Bone removed in two different screw designs

Fig. 10 Long and short TFN

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Expert A2 FN is a modulated intramedullary system with anatomical design (Fig. 11). A flattened lateral surface reduces impingement of the lateral cortex and decreases medialization. This nail also has multiple locking options both distally and proximally with dynamization options along with anti-rotational stability (Fig. 12). This nail is ideally suited for fractures of the shaft of the femur and ipsilateral femoral neck fractures. However, it is not suitable for subtrochanteric fracture isolated neck fractures, supracondylar and intertrochanteric and pertrochanteric fractures. The fractures of the tibia have been facilitated better with the inclusion of an Expert Tibial Nail especially, the upper 1/3 and lower 1/3 fractures. There are fine locking options proximally in various directions and four distally. These multidirectional screws create a fixed angle construct and also provide either primary compression or secondary controlled dynamization. There is provision for end caps which prevent the ingrowth of tissues to ease out the removal of nails whenever necessary (Fig. 13). Both reamed and undreamed techniques can be advocated; even 3 mm ball-tipped guide wires can be removed through nail and nail assembly so that the exchange of tubes is not required. Anatomical bend provides easy insertion and even solid nail options for unreamed technique are available. Titanium alloy provides better

Fig. 11 TFN with a lateral flattened surface

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Fig. 12 TFN

Fig. 13 Expert Tibial Nail with multiple locking options

mechanical and fatigue properties and all locking screws have a double thread closer to the screw head providing better purchase in the cancellous bone. A newer supra patellar approach to the proximal tibial fractures has opened new horizons with extended indications and relatively fewer complications. The entry is above the patella through the medial reticulum with lateral subluxation of the patella in semi-extended position of the limb. Herzog’s curve is 10 . Studies of both Boyko Gueorguiev et al. [22] and Kasper et al. [8] have found angle stable locking of intramedullary nails in tibial fractures results in less fracture gap movement and biomechanically superior fracture healing better.

Conclusion The history of nailing for fractures of the lower limb has been the history of grit and determination of researchers and surgeons around the world to bring out intramedullary nails to be perfect. Ever since the great visionary Gerhard Küntscher

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introduced his clover leaf nail in 1940, various newer nail designs and newer biocompatible materials used for the nails have evolved. Though the biomechanical principle of Küntscher has remained the same even today, we have moved on from simple strain theory to bring out nails made of materials which have higher strength, biocompatibility, and stability.

References 1. Bong MR, Koval KJ, Egol KA. The history of intramedullary nailing. Bull NYU Hosp Jt Dis. 2006;64:94–7. 2. Knothe U, Tate MLK, Perren SM. 300 years of intramedullary fixation – from Aztec practice to standard treatment modality. Eur J Trauma. 2000;26:217–25. 3. Bartonı’cˇek J. Early history of operative treatment of fractures. Arch Orthop Trauma Surg. 2010;130:1385–96. 4. Nelson FRT, Blauvelt CT. A manual of orthopaedic terminology. 8th ed. Philadelphia: Elsevier Health Sciences; 2015. 5. Young S. Orthopaedic trauma surgery in low-income countries: follow-up, infections and HIV. Acta OrthopScandSuppl. 2014;85:1–35. 6. King R. Ku¨ntscher nailing of the tibia – a new tibial jig. Injury. 1980;11:256–7. 7. Groves EWH. Ununited fractures, with special reference to gunshot injuries and the use of bone grafting. Br J Surg. 1918;6:203–47. 8. Fischer AW, Maatz R. Weitere Erfahrungenmit der MarknagelungnachKu¨ntscher. Arch KlinChir. 1942;203:531. 9. Modny MT, Bambara J. The perforated cruciate intramedullary nail: preliminary report of its use in geriatric patients. J Am Geriatr Soc. 1953;1:579–88. 10. Smith J, Greaves I, Porter K. Oxford desk reference – major trauma. New York: Oxford University Press; 2010. 11. Gimeno MS, Albareda JA, Vernet JMC, et al. Biomechanical study of the Grosse-Kempf femoral nail. Int Orthop. 1997;21:115–8. 12. Furman BR, Saha S. Torsional testing of bone. In: An YH, Draughn RA, editors. Mechanical testing of bone and the bone-implant interface. Boca Raton: CRC Press; 2000. p. 219–39. 13. Stedtfeld HW. Rationale of intramedullary nailing. In: Rommens PM, Hessmann MH, editors. Intramedullary nailing: a comprehensive guide. 1st ed. London: Springer; 2015. p. 13–25. 14. DeCoster T. A brief history of medullary nailing, New Mexico perspective. UNMO Orthop Res J. 2012;1:46–54. 15. Wong MK. Intramedullary techniques. In: Porteous M, Bäuerle S, editors. Techniques and principles for the operating room. Davos Platz: Thieme; 2010. p. 157–61. 16. Letechipia J, Alessi A, Rodriguez G, et al. Design and preliminary testing of an active intramedullary nail. Clin Transl Invest. 2014;66:70–8. 17. Da GZ, Wang TM, Liu Y, et al. Surgical treatment of tibial and femoral fractures with TiNi shape-memory alloy interlocking intramedullary nails. In: Proceedings of the international conference on shape memory and superelastic technologies and shape memory materials, Kunming, China, 2–6 September 2001, p. 37–40. 18. Kojic N, Rangger C, Özgün C, et al. Carbon-fibre-reinforced PEEK radiolucent intramedullary nail for humeral shaft fracture fixation: technical features and a pilot clinical study. Injury. 2017;48(S5):S8–S11.

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19. Lewis D, Lutton C, Wilson LJ, et al. Low cost polymer intramedullary nails for fracture fixation: a biomechanical study in a porcine femur model. Arch Orthop Trauma Surg. 2009;129:817–22. 20. Li G, Zhang L, Wang L, et al. Dual modulation of bone formation and resorption with zoledronic acid-loaded biodegradable magnesium alloy implants improves osteoporotic fracture healing: an in vitro and in vivo study. Acta Biomater. 2018;65:486–500. 21. Garlock NA, Donovan J, LeCronier DJ, et al. A modified intramedullary nail interlocking design yields improved stability for fatigue cycling in a canine femur fracture model. Proc IMechE Part H J Eng Med. 2012;226:469–76. 22. Gueorguiev B, Wahnert D, Albrecht D, Ockert B, Windolf M, Schwieger K. Effect on dynamic mechanical stability and interfragmentary movement of angle-stable locking of intramedullary nails in unstable distal tibia fractures: a biomechanical study. J TRAUMA-Injury Infect Critical Care. 2011;70(2):358–65.

Antegrade and Retrograde Femoral Nailing

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Wasudeo Gadegone and Piyush Gadegone

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Kuntscher Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interlocking Intramedullary Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antegrade Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Position of the Patient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Entry Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Piriformis Fossa Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unreamed and Reamed Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interlocking of Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic Versus Static Interlocking Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Retrograde Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nailing in Comminuted and Segmental Femur Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rotational Malalignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prognosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Complications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Most femoral shaft fractures are treated surgically. Early surgical stabilization is linked to lower mortality and fewer complications An intramedullary nail is a metal rod that is placed across the fracture and into the medullary cavity of a bone to give the damaged bone a strong support. The most effective method of treating femoral shaft fractures is intramedullary nailing (IMN). Early fixation within 24–48 h after systemically stable patients’ onset lowers the risk of pulmonary problems, infection rates, and mortality. Intramedullary nailing is currently the “gold standard” for treating femoral shaft fractures. Intramedullary nailing has W. Gadegone (*) · P. Gadegone Gadegone Orthopaedic and Trauma Care Hospital, Chandrapur, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_11

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benefits such as short hospital stays, quick fracture healing, and early limb function. Patients with multiple injuries who were hemodynamically stable benefited the most from early fixation. The IMN’s insertion site lies outside the area of injury, keeping the blood flow in the area and conserving the hematoma’s helpful bone development hormones. Early weight-bearing after intramedullary nailing has additional advantages for maintaining muscle mass, function, strength, and mobility. Intramedullary nailing of diaphyseal femur fractures provides a stable fixation construct that can be applied using indirect reduction techniques and yield high union rate. Extended indication of nailing in complex fractures, a variety of intramedullary nails with modifications in designs, and related procedures are available depending on the pattern of the fracture. Keywords

Fracture of the femoral shaft · Interlocking nail · Entry point · Reaming · Rotational malalignment

Introduction High-energy trauma, such as motor vehicular collisions, is typically the cause of femoral shaft fractures. Incidence of femoral shaft fracture is more common in young males than females of which ratio is 1.74–1. The peak age of femoral shaft fractures in men is between 15 and 24 while the peak age in women at 85 years and beyond [1]. Femoral shaft fractures are occasionally accompanied by polytrauma (several injuries in three or more different bodily areas), which can be fatal. These fractures have the potential to cause severe and long-lasting disabilities, like limb shortening and rotational deformities of the leg. Infection, lingering discomfort, delayed union, and nonunion are additional frequent side effects of these fractures [2]. Ipsilateral femoral neck fractures were discovered in 2–6% of cases, and they were frequently basicervical, vertical, and nondisplaced since the majority of the energy was lost through the femoral shaft. In 19–31% of cases, the femur’s missing neck fracture is discovered [3]. Contrary to unilateral fractures, bilateral femur fractures carry a higher risk of mortality and pulmonary complications. Infrequently do ipsilateral acetabular fractures occur; however, there is a strong correlation with ipsilateral tibial shaft fractures. The primary goal of treatment in the modern era is to stabilize femoral fractures as soon as possible. Fracture fixation via nailing helps to enhance function and lessen long-term consequences like discomfort. Additionally, nailing helps to preserve the blood flow during surgery and reduces damage to the soft tissues close to the bone, which promotes fracture healing and a good functional recovery. In modern era various nailing designs are available to fix the fracture and it is now a gold standard treatment for femoral fractures [4, 5].

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History Aztecs were the first to describe femoral shaft intramedullary nails in the sixteenth century, but Gerald Kuntcher’s successful treatment of femoral shaft fractures in 1939–1940 was made possible by emphasizing the restoration of anatomic alignment while handling soft tissue as little as possible [6]. He is the pioneer in introduction and use of intramedullary nails as the current standard of care for femoral shaft fractures. The Küntscher nail was developed as a cloverleaf nail, which was typically inserted into the medullary canal after the medullary reaming to insert a large diameter nail that provides more nail strength and greater contact areas with the femoral shaft. However, drawbacks of this first-generation nail system included the need for medullary cortical reaming, inability to prevent the collapse at the comminuted sector, and less effective fixation in the metaphyseal fracture. After success in diaphyseal fracture they later realized that in order to have better control over the length and rotation of the fragments, it was necessary to extend the indication of IM nailing to the proximal and distal metaphysis of the femur. As a result, long and some minor developments were described around the world after his pioneering work. Later, Klemm and Schellman (1972)/Kempf et al. (1976) developed the interlocking femoral nails, which could fix the proximal and distal fractures [7, 8]. However, it was found that in the metaphysis, insufficient fixation of the proximal femur and screw failure became the main issues of failure of secondgeneration nails; therefore, to fix the femoral neck and head effectively, thirdgeneration nails with expanded proximal bodies expanded the surgical indications of femoral nailing in proximal fractures, e.g., gamma nails and proximal femoral nails (cephallomedullary).

The Kuntscher Nail For the intramedullary internal fixation of femoral shaft fractures, Gerhard Kuntscher invented the cloverleaf nail in 1940. Later research demonstrated that only isthmic femoral shaft fractures of Winquist types I and II should be treated with the unlocked Kuntscher nail (K-nail). Lack of rotational stability was the primary problem in using K-nails in various forms of femoral shaft fractures. K-nail usage in Winquist type I and type II isthmic fractures is still debatable but it is extensively used in nations with weak health care infrastructure (Fig. 1). The treatment can be performed without an image intensifier and has a comparable functional outcome to an interlocking nail (ILN) in these sorts of fractures. The reasons for this include shorter surgical times, lower implant costs, and less radiation exposure. Introduction of reaming and interlocking bolts proximally and distally improved rotational stability. The interlocking intramedullary nails are now almost universally utilized in developed nations to treat femoral shaft fractures.

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Fig. 1 (a, b) Kuntschner nail with fixation radiograph

Interlocking Intramedullary Nail Early primary stabilization of the femoral shaft is a prime mode of treatment; however, presurgical planning is essential. Almost all types of femoral shaft fractures can now be treated with interlocking intramedullary nailing because of its superior rotational stability and early rehabilitation. Insertion of nail can be done by antegrade and retrograde portals.

Antegrade Nailing Majority of the femoral shaft fracture can be fixed with the antegrade nailing technique. Antegrade techniques frequently need additional support like Poller screws to stabilize the femoral metaphyseal fracture [9, 10]. The antegrade insertion is still today the standard in locking nailing [11].

Position of the Patient Under general or spinal anesthesia, IM nailing for femoral shaft fracture can be done while the patient is lying supine on fracture table (Fig. 2).

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Fig. 2 Illustration of (a) supine positioning on a fracture table with torso tilted to opposite side and opposite leg in lithotomy and (b) lateral position

The most common technique is supine because, especially in highly comminuted fractures, maintaining steady traction is the most important step in closed reduction, reaming, nail insertion, and distal interlocking. The biggest disadvantage of this position is that some patients have difficulty obtaining a proper piriformis entry or trochanteric fossa. The difficulty comes from the bulky soft tissue in obese patients, the restricted space between the greater trochanter and iliac crest in small patients, and the overhanging of the larger trochanter over the trochanteric fossa. Alternate positioning laterally on the radiolucent table, particularly with subtrochanteric fracture and in obese patient flexing the hip, makes it simple to locate an unimpeded path to the entry site. Make incision approximately 3 cm above GT in line with femur move incision superior if the patient is obese. Dissect down to greater trochanter use

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cautery through subcutaneous tissue and sharp dissection through the fascia lata, palpate tip of greater trochanter, and make a entry portal at piriformis fossa or tip of the trochanter. Pass a guide wire after fracture reduction and check in C-arm distal location. The reaming is done, appropriate length and diameter nail is passed, and proximal and distal locking is carried out. Most difficult part is it necessitates constant monitoring to protect the fracture from loss of reduction while nailing and also to prevent rotational malalignment.

Entry Points The lateral entrance, piriformis, and tip of the trochanter are the three commonly utilized methods for inserting a nail.

Piriformis Fossa Entry When employing the piriformis fossa entry approach, a straight design nail is used, and its trajectory aligns with the long axis of the femur. In the area of the piriform fossa, the central axis of the medullary canal exhibits greater precision in the coronal view. The apex of the greater trochanter features a small, shallow depression known as the piriform fossa. The piriform fossa serves as the optimal site for the insertion of straight nails [12] (Fig. 3). This method has several drawbacks, including potential damage to the blood supply of the femoral head and injury to the abductor muscles, which can result in a Trendelenburg gait. The following factors contribute to the difficulties associated with this method: the presence of bulky soft tissue in obese patients, the narrow

Fig. 3 Illustration depicting a piriformis fossa entry femoral nail (a), preoperative, and postoperative radiographs (b), demonstrating the application of the nail for a diaphyseal femur fracture

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space between the greater trochanter and iliac crest in smaller patients, and the overhanging of the greater trochanter over the trochanteric fossa. When using a straight nail in this method, there is a risk of perforating the anterior cortex or starting too far posterior on the greater trochanter. However, employing the medial trochanteric entry technique helps to spare the abductors to a greater extent and facilitates establishing the correct starting point. Additionally, the anterior and lateral bow of the nail conforms to the curvature of the femur, reducing the risk of perforation. It is important to note that using a straight nail in this approach still poses a potential risk of anterior cortex perforation or an incorrect starting point on the greater trochanter [13, 14]. Alternatively, the entry points located in the anterior third and posterior two-thirds of the tip of the greater trochanter are widely accepted. Trochanteric tip entry: The greater trochanter’s tip was employed as an entry point with the introduction of the angled nail in order to prevent septic arthritis and potential disruption of the blood supply to the femoral head after intracapsular infection at the time. In comparison to the piriformis entrance approach, the trochanteric entry technique requires less time during surgery and fluoroscopy (Fig. 4). Long-term functional results are comparable between the two methods. A successful IM nailing results from a good entry point. Medial to the tip of the trochanter is the well-accepted entry portal for proximal femoral fractures. Therefore, it is better to invest significant time in creating a proper entry site even though you may make a few poor attempts [15, 16]. Lateral trochanteric entry: This entry point was used when angled nail were used in the treatment fractures of intertrochanteric and subtrochanteric region. To avoid avascular necrosis of the femoral head after antegrade femoral nailing in a young patient, it is essential to avoid the trochanter fossa. When doing nailing on young adolescents, it is typically employed to spare the trochanteric epiphysis where nailing is indicated. For best results that do not adversely effect bone development, a solid understanding of

Fig. 4 Illustration depicting a trochanteric entry femoral nail (a) and preoperative and postoperative radiographs (b) demonstrating the application of the nail for a diaphyseal femur fracture

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anatomy and biomechanics is necessary. After the age of 16, using trochanteric entry nails is safe and does not hinder the growth of the trochanter [17].

Unreamed and Reamed Nailing In theory, unreamed nailing is expected to be faster, simpler, and less disruptive to blood flow, promoting healing and reducing the risk of infection. However, inadequate fixation of a fracture is the primary cause of difficulties associated with regular nailing procedures. Studies have shown that fractures treated with nonreamed nailing have slightly higher rates of delayed union and nonunion compared to those treated with reamed nails in femoral shaft fractures [18]. Currently, it is mainly used in compound fractures for the initial stabilization of the fracture. Intramedullary nailing benefits from medullary canal reaming techniques both mechanically and biologically. Reaming deposits osteoprogenitor cells and inductive chemicals at the fracture site, acting as a bone graft. Reaming significantly reduces nonunion rates by more than four times. Reamed and locked intramedullary nails have reported union rates between 97% and 100%, whereas nonreamed approaches have union rates of 84% [18]. Initially, reaming was believed to increase the risk of pulmonary problems such as fat emboli syndrome or inflammatory responses affecting respiratory function. This was attributed to the venous embolization of fat caused by increased pressure in the femoral canal during the insertion of tools or implants. However, studies have shown that although reaming increases blood fat levels, it does not worsen pulmonary impairment. Although reaming increases intraosseous bleeding, patients’ postoperative transfusion needs remain the same [19]. In the case of a lengthy oblique or spiral fracture at the isthmus, flexible reamers are used, which wrap around the fracture zone while missing one cortex. Long-term use of bisphosphonates can also lead to the formation of hard endosteal callus, which may obstruct or cause the cortex to rupture in the event of an atypical femoral fracture. In such cases, it may be necessary to remove the callus using a long, narrow chisel to widen the medullary canal before inserting the femoral nail. When the fracture is located in the distal part of the femoral shaft, the nail tip must be inserted into the femoral condyle for distal interlocking. The nail tip can be advanced until it contacts the V-shaped corner formed by the lower Blumensaat and upper intercondylar articular lines.

Interlocking of Nail Generally, the locking procedure involves the insertion of two screws from the lateral to medial side. The targeting guide, which is attached, typically provides the holes for inserting the proximal interlocking screws. For distal fixation, a freehand technique is commonly used. The option that will achieve appropriate proximal fixation should be chosen. Modern femoral nails offer a range of interlocking solutions for treating associated fractures in the proximal (femoral neck and trochanteric) and distal (supracondylar) regions (Fig. 5).

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Fig. 5 Illustration showing lesser trochanter transverse locking (a) and trochanter to head neck oblique locking (b)

One of the challenges in proximal interlocking is the right positioning of the femoral neck and head screw (reconstruction screw), which is most frequently locked in place at the level of the lesser trochanter from the lateral to the medial. Contrary to placing an oblique screw from the larger to the lesser trochanter, inserting a reconstructive screw requires specific expertise, especially if two are needed. The level of the proximal interlocking holes in the nail must coincide with the anteversion and neck of the femur. The long reconstruction screw’s tip must be positioned in the lateral view in the center of the femoral head in order to be effectively inserted into the bone [20].

Dynamic Versus Static Interlocking Fixation By the late twentieth century, most nails only had static round holes as a mode of interlocking; as a result, it was necessary to remove all interlocking screws from one main piece in order to produce the dynamization effect (Figs. 6 and 7).

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Fig. 6 Preoperative (a) and postoperative (b) radiographs showing static locking in a short oblique femoral shaft fracture

Load-bearing on the fracture callus is believed to assist in fracture healing and patient rehabilitation, as advocated by proponents of routine dynamization. However, according to Brumbeck et al. [21], most fractures healed successfully when treated in the static mode, leading to the recommendation against routine dynamization. While static locking of intramedullary nails in femoral shaft fractures does not significantly hinder fracture healing, transverse and short oblique fractures at the isthmic zone often necessitate dynamic locking. Although occasional cases may require it, comminuted unstable fractures do not typically require routine conversion to dynamic fixation. Furthermore, the dynamic unlocking mode occasionally resulted in angular instability and excessive shortening in 10% of patients due to displacement of the undiagnosed fracture line. Consequently, the static mode became the standard approach for interlocking fixation in femoral nailing. Modern femoral nail systems generally provide two options for interlocking fixation, namely dynamic and static modes, in both the distal and proximal sections. Each proximal and distal component features a single dynamic hole [22].

Retrograde Nailing Retrograde nailing has gained popularity in recent years due to the availability of nails offering multiple locking options, variable length, and the ability to achieve secure fixation in distal femoral and distal junctional fractures [23]. In addition to

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Fig. 7 Preoperative (a) and postoperative (b) radiographs showing dynamic locking in a short oblique fracture of the shaft of femur

these advantages, retrograde nailing is indicated in cases of ipsilateral femoral neck fractures, acetabular fractures, bilateral femur fractures, tibia fractures (floating knee injuries), pregnancy, and morbidly obese individuals. Similar results for antegrade nailing have been shown in studies. The rates of unionization (100% vs. 99%), malunion (11% vs. 13%), and nonunion (6% vs. 6%) are comparable for antegrade and retrograde techniques. In contrast to anterograde nailing, which causes hip pain and stiffness, retrograde nailing frequently results in knee pain and stiffness [24, 25]. Supine position on a radiolucent table in 30–40 degree of flexion of knee establishes the entry point 2–3 mm anterior to Blumensaat’s line in the midline. Once the correct entry point is determined, a guide wire is inserted 3–4 cm. Do not enter posterior to the Blumensaat’s line, to prevent damage to the anterior cruciate ligament upon reaming. The radiograph shows the desired 30 flexion of the knee joint (Fig. 8). With reduced flexion, the insertion of the guide wire into the tibial plateau becomes more difficult. Conversely, excessive flexion poses a risk to the articular surface and obstructs the path of the patella. After the fracture is reduced using a clamp, poller screws, or an external fixator distractor, the guide wire is passed and confirmed using a C-arm. Subsequently, reaming is performed along the guide wire until reaching the trochanter. This procedure starts approximately 2–3 mm anterior to the distal end of Blumensaat’s line on the femur, within the intercondylar notch. Reaming can be accomplished through the sleeve, allowing for the passage of an appropriate length and diameter nail up to the level of the lesser trochanter to

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Fig. 8 Clinical picture (a) showing the positioning of the patient and intraoperative fluoroscopy images (b) showing the entry point in retrograde femoral nailing

stabilize the fracture. Distal locking is performed using a jig, while proximal locking at the lesser trochanter is done manually (Figs. 9 and 10). There is a risk of iatrogenic damage to the knee’s ligaments and cartilage with this technique. The introduction of new designs of distal spiral blades has effectively addressed rotational instability in distal femoral fractures. Additionally, the use of retrograde nail insertion may offer a simpler procedure, reduced blood loss, and alleviate the common problems and pain associated with knee surgery [26].

Nailing in Comminuted and Segmental Femur Fractures These fractures present challenging and intriguing difficulties. Segmental fracture intramedullary nailing is technically challenging yet produces outstanding results in these otherwise challenging fractures. Proper length nail and diameter nail intramedullary nailing is successful in stabilizing the bones in patients with grade I and grade II comminuted fractures. Comminuted fractures of grades III and IV can

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Fig. 9 Preoperative and postoperative radiographs showing retrograde nailing for fixation of a spiral distal femoral fracture

shorten and rotate because they are unstable. Therefore, we think that doing an open reduction and cerclage wire of these fractures is feasible in order to achieve anatomic restoration in a young patient. Preoperative traction, the increased use of cerclage wire, and augmentation plate nearly eliminated these more frequent problems of shortening and rotation. Multiple locking proximally and distally achieves adequate stability to mobilize the patient early to prevent complication of knee stiffness (Figs. 11 and 12). Determining leg length can be exceptionally challenging when dealing with comminuted fractures [27, 28]. Furthermore, complications may arise, such as knee sepsis, stiffness, and hyperextension of the femoral component, resulting from an incorrect nail entry point. Additionally, there is a risk of distal interlocking screws loosening due to poor bone quality in the periprosthetic supracondylar region. Moreover, retrograde nailing can lead to reduction loss, potentially resulting in nonunion or malunion.

Rotational Malalignment Malrotation is a relatively common complication that can occur following femoral nailing, with a frequency of up to 25%. When the femur is malrotated by more than 14 degrees from its neutral position, it can significantly affect gait mechanics and efficiency. While there is ongoing debate regarding the precise definition of malrotation, it is generally agreed upon that rotational malalignment of less than 10 degrees is acceptable, while malrotation exceeding 30 degrees is considered a deformity requiring correction.

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Malrotation of more than 14 degrees from the neutral position can have adverse effects on gait mechanics and efficiency. Interestingly, patients tend to tolerate internal misalignment better than external misalignment. To measure rotation, two useful landmarks are cortical overlap and fluoroscopic comparison of the rotation of the lesser trochanter. However, the most accurate method for determining rotation is performing a computed tomography scan on both limbs.

Fig. 10 Preoperative radiographs demonstrating an acute fracture of the shaft of femur and a refracture of an united tibia fracture (floating knee injury) being fixed with retrograde femoral nailing and tibial nailing

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Fig. 10 (continued)

Patients with malrotation of the femur may experience various issues affecting their hips, knees, or lower leg. Distal femoral shaft fractures are particularly prone to rotational malalignment, with higher incidence rates. Transverse, segmental, and comminuted fractures are among the fracture patterns that are most susceptible to malrotation [29, 30].

Prognosis Reamed nailing has demonstrated excellent functional outcomes with a 100% retrograde and 99% antegrade union rates. Patients who undergo early definitive fixation experience superior results, encounter fewer complications, and have lower mortality rates. Following intramedullary nailing, patients are permitted to bear weight as tolerated, which accelerates their rehabilitation and restores their preoperative mobility. However, in the elderly population, recovery may pose greater challenges due to multiple comorbidities, often resulting in slowed progress. Bilateral femoral fractures, especially when accompanied by additional injuries and physiological instability, significantly increase the risk of mortality. Patients with unilateral shaft fractures exhibited an overall in-hospital death rate of 1.4%. In contrast, those with bilateral femur fractures, along with associated injuries, faced

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Fig. 11 Preoperative (a) and postoperative (b) radiographs showing fixation of a comminuted femoral shaft fracture with a reconstruction nail

Fig. 12 Preoperative and postoperative radiographs showing retrograde nailing for fixation of a segmental and comminuted femoral shaft fracture

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mortality rates of 31.6% and 9.8%, respectively. It is crucial to note that the risk of death increases fivefold if treatment is delayed beyond 48 hours [31].

Complications The antegrade nailing of the femur offers several advantages, including a high union rate and a low risk of malunion. However, this procedure is associated with potential complications in the hip region due to its entry point and route. One notable complication is heterotopic ossification around the hip. During antegrade nailing, nerve injuries can occur, both iatrogenic (caused by medical intervention) and positioning related. For example, about 15% of pudendal nerve injuries are caused by patients being positioned with a perineal post [24]. Retrograde nailing, which involves inserting the nail in the opposite direction, can lead to damage to the sciatic nerve, especially from excessive traction or surgical equipment. Intraoperative complications during femoral nailing may include malalignment, compartment syndrome, thermal necrosis, iatrogenic fractures, and neurovascular damage. Reaming, a process of enlarging the intramedullary canal, can generate temperatures as high as 57 degrees Celsius, resulting in thermal necrosis due to enzyme denaturation and potentially delaying fracture healing [32]. The deep femoral artery (DFA) or superficial femoral artery (SFA) may sustain vascular damage following instrument or implant penetration. Despite the utilization of safe zones for implant insertion, abnormal anatomy can put patients at risk of iatrogenic harm. Fracture propagation is a concern during nail insertion through the greater trochanter, knee, and implant, and anterior cortical perforation may occur after surgery. Excessive anterior femoral bow, caused by an excessively low radius of curvature, increases the likelihood of anterior perforation. Additionally, postoperative fractures most commonly occur at the ends of intramedullary nails or plates due to stress risers. Postoperative complications of femoral nailing encompass hip and knee discomfort, pulmonary embolism, infection, osteomyelitis, malunion, delayed union, and nonunion. Delayed union is more prevalent than nonunion in femoral fractures [33]. Nonunion occurs when a fracture fails to heal or shows no evidence of healing after six months. Infection is one potential cause of nonunion and should be considered during the diagnostic process. Surgical intervention for nonunion may involve revision fixation with or without a bone graft, depending on the underlying cause.

Conclusion With the introduction of the locking system and the inclusion of straight and angled nails with specific curvature for each side, interlocking nails combine the advantages of closed medullary nailing. They provide a stable nail-bone construct during the

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healing process. Interlocking nails are particularly beneficial for fractures that are not suitable for standard medullary fixation, including those with severe comminution, bone loss, and fractures beyond the isthmic zone. By using transfixing interlocking screws, these fractures can be effectively fixed. Antegrade and retrograde nailing of the femur offer a high rate of union and minimal risk of malunion. However, it is crucial to adhere to surgical principles to avoid complications. Both retrograde and antegrade nailing techniques yield excellent results, with retrograde nails being advantageous for distal third fractures and antegrade nailing for proximal femoral fractures. Skill and minimally invasive surgery are necessary for favorable outcomes in both techniques.

References 1. Salminen ST, Pihlajamäki HK, Avikainen VJ, Böstman OM. Population based epidemiologic and morphologic study of femoral shaft fractures. Clin Orthop Relat Res. 2000;(372):241–9. https://doi.org/10.1097/00003086-200003000-00026. PMID: 10738433 2. Fakhry SM, Rutledge R, Dahners LE, Kessler D. Incidence, management, and outcome of femoral shaft fracture: a statewide population-based analysis of 2805 adult patients in a rural state. J Trauma. 1994;37(2):255–60. https://doi.org/10.1097/00005373-199408000-00018. 3. Wolinsky PR, Johnson KD. Ipsilateral femoral neck and shaft fractures. Clin Orthop Relat Res. 1995;318:81–90. 4. Winquist RA, Hansen ST Jr, Clawson DK. Closed intramedullary nailing of femoral fractures. A report of five hundred and twenty cases. J Bone Joint Surg Am. 1984;66(4):529–39. 5. Rudloff MI, Smith WR. Intramedullary nailing of the femur: current concepts concerning reaming. J Orthop Trauma. 2009;23(5 Suppl):S12–7. https://doi.org/10.1097/BOT. 0b013e31819f258a. 6. Küntscher G. The marrow nailing method, translation by U.S. Germany: Fleet Naval Forces; 1947. (reprint of the original edition by Stryker) 7. Klemm K, Schellmann WD. Dynamic and static locking of the intramedullary nail. Monatsschr Unfallheilkd Versicher Versorg Verkehrsmed. 1972;75:568–75. 8. Kempf L, Grosse A, Lafforrgned L. L’enclouae avec blocage de la rotation on clou bloque principles, technique, indications et premiers resultants. Communication ala journee d’hiver SOFCOT; 1976. 9. Krettek C, Miclau T, Schandelmaier P, Stephan C, Mohlmann U, Tscherne H. The mechanical effect of blocking screws (“Poller screws”) in stabilizing tibia fractures with short proximal or distal fragments after insertion of small-diameter intramedullary nails. J Orthop Trauma. 1999;13:550–3. 10. Krettek C, Stephan C, Schandelmaier P, Richter M, Pape HC, Miclau T. The use of Poller screws as blocking screws in stabilising tibial fractures treated with small diameter intramedullary nails. J Bone Joint Surg Br. 1999;81:963–8. 11. Court-Brown CM, Browner BD. Locked nailing of femoral fractures. In: Browner BD, editor. The science antegrade femoral nailing for femoral shaft fracture science and practice of intramedullary nailing. 2nd ed. William & Wilkins; 1996. p. 161–82. 12. Nork SE. Femoral shaft fracture. In: Court-Brown CM, et al., editors. Rockwood and Green’s fractures in adult. 8th ed. Philadelphia: Wolters Kluwer; 2015. p. 2149–228. 13. Grechenig W, Pichler W, Clement H, Tesch NP, Grechenig S. Anatomy of the greater femoral trochanter: clinical importance for intramedullary femoral nailing anatomic study of 100 cadaver specimens. Acta Orthop. 2006;77(6):899–901. 14. Farhang K, Desai R, Wilber JH, Cooperman DR, Liu RW. An anatomical study of the entry point in the greater trochanter for intramedullary nailing. Bone Joint J. 2014;96-B:1274–81.

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15. Papadakis SA, Shepherd L, Babourda EC, Piriform PS, trochanteric fossae. A drawing mismatch or a terminology error? A review. Surg Radiol Anat. 2005;27:223. 16. Gausepohl T, Pennig J, Koebke J, Harnoss S. Antegrade femoral nailing: an anatomical determination of the correct entry point. Injury. 2002;33(8):701–5. 17. Townsend DR, Hoffinger S. Intramedullary nailing of femoral shaft fractures in children via the trochanter tip. Clin Orthop Relat Res. 2000;376:113–8. 18. Li AB, Zhang WJ, Guo WJ, Wang XH, Jin HM, Zhao YM. Reamed versus unreamed intramedullary nailing for the treatment of femoral fractures. A metaanalysis of prospective randomized controlled trials. Medicine. 2016;95(29):e4248. 19. Hӧgel F, Gerlach UV, Südkamp NP, Müller CA. Pulmonary fat embolism after reamed and unreamed nailing of femoral fractures. Injury. 2010;41:1317–22. 20. Kempf I, Grosse A, Beck G. Closed locked intramedullary nailing. J Bone Joint Surg Am. 1985;67(5):709–20. 21. Brumback RJ, Uwagie-Ero S, Lakatos RP, Poka A, Bathon GH, Burgess AR. Intramedullary nailing of femoral shaft fractures. Part II: fracture-healing with static interlocking fxation. J Bone Joint Surg Am. 1988;70(10):1453–62. 22. Clatworthy MG, Clark DI, Gray DH, Hardy AE. Reamed versus unreamed femoral nails a randomised prospective trial. J Bone Joint Surg (Br). 1998;80-B:485–9. 23. Kim JW, Oh CW, Oh JK, Park KH, Kim HJ, Kim TS, Seo I, Park EK. Treatment of infra-isthmal femoral fracture with an intramedullary nail: is retrograde nailing a better option than antegrade nailing? Arch Orthop Trauma Surg. 2018;138(9) 24. Ricci WM, Bellabarba C, Evanoff B, Herscovici D, DiPasquale T, Sanders R. Retrograde versus antegrade nailing of femoral shaft fractures. J Orthop Trauma. 2001;15(3):161–9. 25. Carmack DB, Moed BR, Kingston C, Zmurko M, Watson JT, Richardson M. Identification of the optimal intercondylar starting point for retrograde femoral nailing: an anatomic study. J Trauma. 2003;55(4):692–5. 26. Sanders R, Koval KJ, DiPasquale T, Helfe DL, Frankle M. Retrograde reamed femoral nailing. J Orthop Trauma. 2014;28(Suppl 8):S15–24. 27. Agarwala S, Menon A, Chaudhari S. Cerclage wiring as an adjunct for the treatment of femur fractures: series of 11 cases. J Orthop Case Rep. 2017;7:39–43. 28. Wang T-H, Chuang H-C, Kuan F-C, Hong C-K, Yeh M-L, Su W-R, Hsu K-L. Role of open cerclage wiring in patients with comminuted fractures of the femoral shaft treated with intramedullary nails. J Orthop Surg Res. 1 29. Yang KH, Han DY, Jahng JS, Shin DE, JPark JH. Prevention of malrotation deformity in femoral shaft fracture. J Orthop Trauma. 1998;12:558–62. 30. Ju B, Moon YJ, Lee KB. Use of lesser trochanter profle as a rotational alignment guide in intramedullary nailing for femoral shaft fracture. J Bone Joint Surg Am. 2021;103:e89. (1–6). 29 31. Olerud S. The effects of intramedullary nailing. In: Browner BD, editor. The science and practice of intramedullary nailing. 2nd ed. William & Wilkins; 1996. p. 71–6. 32. Berkes MB, Little MTM, Lorich DG. Complications of intramedullary nailing. In: Rommens P, Hessmann M, editors. Intramedullary nailing. London: Springer; 2015. https://doi.org/10.1007/ 978-1-4471-6612-2_8. 33. Wu KJ, Li SH, Yeh KT, Chen IH, Lee RP, Yu TC, Peng CH, Liu KL, Yao TK, Wang JH, Wu. The risk factors of nonunion after intramedullary nailing fixation of femur shaft fracture in middle age patients. WT Medicine (Baltimore). 2019;98(29):e16559. https://doi.org/10.1097/ MD.0000000000016559. PMID: 31335740

Part III Principles of Orthopaedic Plating

General Principles of Orthopaedic Plating and Overview

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristics of Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications of Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disadvantages of Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functions of Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Types of Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

The screw was invented by Archimedes in the third century BC. Lane introduced a metal plate for internal fixation for the first time. Over the period of years, the plates and screws have evolved into different sizes and shapes by different people. The material used for making the plates and screws also has improved in characteristics. A bone plate is a load-bearing device. Absolute stability is achieved when bone heals with primary healing. An ideal implant should be biocompatible, durable, and inert, and with minimum failure. Stainless steel of 316 L grade was being used until recently. Titanium is more biocompatible and permits bending and contouring during surgery and has become popular. It is also magnetic resonance compatible.

S. N. Bhat (*) Department of Orthopaedics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Udupi District, Karnataka, India e-mail: [email protected] M. A. Kumar Department of Orthopaedics and Trauma, Tejasvini Hospital, Mangalore, Karnataka, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_12

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This chapter describes the history, characteristics, biomechanics, indications, disadvantages, functions, and types of bone plates. Keywords

Principles of plating · Characteristics of plates · Biomechanics · Disadvantages · Functions · Types of plates

Introduction Plate osteosynthesis has evolved to address the three important aspects of fracture management: giving stable and durable fixation, preserving normal biology, and enhancing fracture healing [1]. An ideal implant should be biocompatible, inert, and long lasting, with minimum failure rate. Open reduction and anatomical fixation with interfragmentary compression reduced the fixation failures.

History Archimedes invented the screw in the third century BC. The system of fracture fixation using screws and plates was introduced by three European surgeons (Carl Hansmann [1853–1917], William Arbuthnot Lane [1856–1943], and Albin Lambotte [1866–1956]) independently toward the end of the nineteenth century. Hansmann (Fig. 1) of Heidelberg University, Germany, used plates first for fixation of long bone fractures in 1886 [2, 3] (Fig. 2). Fig. 1 Hansmann (1853–1917) of Heidelberg University

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Fig. 2 Hansmann’s plate

Fig. 3 Lambotte’s plate

Fig. 4 Sherman’s plate

A few years later, in 1895, Lane introduced a plate made of metal for internal fixation. Lane’s plate had problems of corrosion and eventually lost popularity. Lambotte invented a plate (1909) which was thin and had round tapered ends [1, 2] (Fig. 3). Sherman designed a plate with round holes (Fig. 4) and also published the properties of bone screws in 1912. Both Lambotte’s and Sherman’s designs were eventually abandoned due to their insufficient strength. Stainless steel was introduced for use in implants in 1926 [4].

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The Eggers plate (1948) (Fig. 5) was designed with two long slots permitting the screw heads to slide. Eggers presumed it could compensate for the bone resorption at the fracture ends. The limitations of his plate were weak which resulted in loss of fixation [5]. Bagby et al. [6] designed low-profile plate with oval holes for eccentric screw placement. Phillips and Woodrugg designed screw heads without slipping at the driver–head interface [7]. Eggers [8] used the term contact compression factor, which has been described to stimulate osteogenesis. Point-contact fixator (PC-Fix) (Fig. 6) is actually an internal fixator. The unicortical screws locked into the plate, provided angular stability, and prevented the bone from being pulled toward the plate. The compression plate was first designed by Robert Danis. He also modified the machine screws for orthopaedic use. Danis’ plate (1949) prevented interfragmentary motion (Fig. 7). The side screw had to be tightened to achieve the stability of fixation by interfragmentary compression [3]. Fig. 5 Eggers plate

Fig. 6 Point-contact fixator

Fig. 7 Danis’ compression plate

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In 1958, Müller and three more Swiss surgeons formed the Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation (AO/ASIF). They are the pioneers of modern plating.

Characteristics of Plates A bone plate is a load-bearing device; it bears the load transmission when it is used to fix the fracture. In contrast, interlocking nails are load sharing devices, which share the load with bone. A plate is most effective when placed on the tension side. When the fracture is not comminuted and is well reduced, the transfer of load is shared by the plated bone [9]. The plate will be subjected to bending forces, if there is a gap at the fracture site. Usually, it happens when the fractured bone is misaligned. In some cases, the plate may bend to and fro as the improper bone-plate construct is loaded, causing fatigue failure of the plate. The designing of a plate needs several factors to be considered: 1. The system of fixation should be a stable construct when plates and screws are used. 2. Healing of the fracture complex requires adequate blood supply. The blood supply of the bone should be disrupted minimally, either by the surgical technique or by the implant. 3. The plate should be minimally stressed. 4. Uninjured tissues are taken care to prevent damage. 5. The plate should be made of proper materials to prevent fatigue failure. Titanium is more biocompatible and permits bending and contouring plates during surgery. Though expensive, it is biologically more inert and less allergic than stainless steel. Titanium plates have already become popular for internal fixation. One important thing is to know that plates and screws must be of the same material to prevent corrosion [5].

Biomechanics Here are some of the terminologies related to the characteristics of a plate. 1. The working distance of the plate is the length between the two screws nearest to the fracture on each end of the fracture. 2. The stiffness of the fixation construct increases with lesser working distance. 3. Bending rigidity is proportional to the third power of thickness. 4. Young’s modulus of elasticity of titanium closely approximates the cortical bone.

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The surgical treatment of long bone fractures with plates and screws is a standard technique. It is the gold standard to have anatomic reduction and rigid fixation using compression plating, following the AO/ASIF principles. However, locking plate technology and less invasive surgical techniques have recently become accepted modalities to treat complex fractures. Locking plate has been widely accepted for fixing osteoporotic bone fractures [10]. Elastic fixation allows bending, torsion, and shear and is not recommended because of possible delayed healing of fracture. Rigid plates carry a significant load relieving the plated bony fragments from stimuli needed for osteogenesis and to maintain bone mass. Plates and screws are used to fix bone fractures using any one of these two following methods and principles [10]: 1. Open, anatomic reduction of the fracture and interfragmentary compression (method) achieving absolute stability (principle) 2. Restoration of the alignment and splinting of the fractured ends (method) achieving relative stability (principle) Absolute stability is when constructs heal with primary bone healing. There must be a low strain at the fracture site with high fixation stiffness. Screws that lock into threaded plate holes provide an alternative method of achieving angular stability in locking plates by having purchase in the metaphyseal fragment of the bone and locking into the plate holes. The locking plate and screw systems are very suitable in the osteoporotic bone of the elderly by acting as internal fixators.

Indications of Plates There are several indications for plates. Plates are load-bearing devices in contrast to interlocking nails, which are load-sharing devices. Plates can be used in any of the following situations but not limited to: • • • • • • • • •

Shaft and periarticular fractures of long bones. When rigid fixation of fractures is desired. When fractures need accurate anatomical realignment. Where screws alone are inadequate, after an interfragmentary fixation, it needs to be protected. When load sharing can be achieved with or without bone grafting at the site. When intramedullary nail is contraindicated like open growth plate, narrow medullary canal, deformity due to malunion, severely contaminated open/infected fractures, and fracture extending to the line of locking screws. Non-union of long bones. After a corrective osteotomy for malunion. Periprosthetic fractures.

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Disadvantages of Plates There are some drawbacks of plate osteosynthesis. • The surgical approach requires periosteal stripping jeopardizing the blood supply of bone. • Healing of bone is by primary intention, especially when compression is used. • There is no callus formation resulting in poor bone welding. • There may be osteonecrosis at fracture site if excessive compression is used. • The screw holes are weak points after implant removal and refracture may occur. Some fractures are more prone to complications when fixed with plates like transverse diaphyseal fractures in weight-bearing bones. Such fractures are contraindications for plate fixation.

Functions of Plates Standard plate fixation involves the following steps: exposure of the fracture site, hematoma removal, accurate reduction, and sometimes with interfragmentary fixation. The periosteal blood supply is important for bone healing, and periosteum stripping should be minimum to promote healing [11]. Careless soft tissue handling also may jeopardize local blood supply and delays union. Plate fixation of the diaphysis by an accurate reduction and interfragmentary compression provides absolute stability. Sometimes, plates are indicated in periarticular fractures to neutralize the axial forces on the compression screws to promote healing [9]. A fracture anatomically reduced without a gap and fixed with absolute stable fixation will heal primarily. A plate can be used in several ways on the bone [10]. Concave plates: Using with a concave bend on the plate to ensure compressive forces on both the far and near cortices of the fracture (Fig. 8). Neutralization plates: A primary fixation with an interfragmentary screw and spanned by using a plate, neutralizing the disruptive forces (Fig. 9). Buttress plates: Many fractures shorten and displace under axial load. Such a fracture needs to be stabilized by applying a plate to the main fragment buttressing the other fragment, preventing displacement (Fig. 10). Bridge plates/Waveplates: In comminuted diaphyseal fractures, a plate can be applied to the main fragments spanning the fractured portion. It helps to restore length, axial alignment, and rotational alignment and preserves the biology of the comminuted zone (Fig. 11). Tension band plates: If a plate is fixed on the tension side of the bone, the same load generates compression across the fracture interface (Fig. 12). Compression plates: By placing a cortical screw eccentrically into an oval hole in the plate, compression can be achieved at the fracture site. Compressing together the main fragments of a linear fracture will result in absolute stability (Fig. 13).

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Fig. 8 Concave plate producing compression

Fig. 9 Neutralization plate

Types of Plates In 1958, AO devised plates for long bone fractures, starting with a round-holed plate called Müller’s plate (to be used with an external compression device) [10] (Fig. 14a, b). Thinner bones like radius, ulna, and fibula used to be fixed with semi-tubular or one-third tubular plates. They have a semi-tubular or one-third tubular cross-section; they have round holes like a Müller’s plate. They are weak plates (Fig. 15a, b). The dynamic compression plate (DCP) was developed by AO in 1969. The DCP has a self-compressing oval hole design [3] (Fig. 16). The flat undersurface of the DCP interferes with the blood supply of the underlying bone cortex when compressed by the screws. The mid-portion of the plate should be at the fracture site, and compression is achieved by putting eccentric screws in the holes near the fracture. Remaining screws are put centrically. The “footprint” of a plate is the area of the bony cortex in contact with the undersurface of the plate (Fig. 17).

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Fig. 10 Buttress plating

The preservation of the blood supply of the underlying cortex required a reduction in the footprints of plates, and hence limited contact dynamic compression plate (LC DCP) (1994) (Fig. 18a, b) was created. The LC DCP has a fluted undersurface reducing the plate bone contact. In this plate, the holes are uniformly arranged. Compression can be achieved in either direction. It is useful in short segmental fractures, to achieve compression at both the fractures. Before the introduction of locking plates, angular stability for the management of metaphyseal fractures was achieved using fixed angle devices. The 95 angled blade plate is one such implant (Fig. 19). In distal radius and tibial plateau fractures, anatomical reduction of the intraarticular fracture prevents the secondary arthritis. A stable articular and metaphyseal fixation is achieved using buttress plates (Fig. 20a, b) to facilitate the union of fracture [12]. Titanium alloys came into the picture in the 1970s [4]. In 2001, the locking compression plate (LCP), with combination holes, was designed by AO (Fig. 21). The combination hole permits the insertion of both

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Fig. 11 Bridge and wave plates

standard screws and locking screws. The locking screws have threaded heads that get locked into the threaded portion of the hole of the locking plate. The locking compression plates were made of titanium and are MRI compatible. There is another category of plates called reconstruction plates (Fig. 22) having notched edges. They can be bent “on the flat” and by conventional bending (Fig. 23). They are commonly used in various complex anatomical sites, such as the distal humerus, the pelvis, the clavicle, etc. The latest inventions are the anatomical locking plates. They are precontoured to the shape of the bones and are side specific (Fig. 24). Calcaneal plates (Fig. 25) are a type of locking plates which are also side specific. A calcaneal plate has multiple holes and can address various fracture patterns of the calcaneum. Biodegradable implants (plates and screws) made of poly-L-lactic acid (PLA) and polyglycolic acid are being tried to avoid the necessity of implant removal. An axially compressible plate (ACP) which inserts press-fit around screw holes has been designed. The evidence suggests that bone loss is caused by stress shielding and not by interference with cortical blood supply secondary to the bone–plate interface. These bioresorbable inserts allow for

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Fig. 12 Tension band plates Fig. 13 Compression plating

Fig. 14 (a, b) Müller’s plate. Note the slot on the undersurface to fix the compression device

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Fig. 15 (a, b) One-third tubular plate, superior and undersurface

Fig. 16 Dynamic compression plate. A 3.5 system plate and 4.5 system heavy duty plate

Fig. 17 Cross-section of bone with the plate showing the area of contact

Fig. 18 (a, b) Limited contact dynamic compression plate, both surfaces. The undersurface design reduces the footprint

1. Micromotion in the axial plane, which promotes healing during fracture healing 2. Degradation over time to decrease stress shielding during the remodeling phase Ongoing experimental results were encouraging.

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Fig. 19 A 95 angled condylar blade plate

Fig. 20 (a, b) A 3.5 system buttress plate (a) and 4.5 system buttress plate (b)

Fig. 21 (a, b) A 3.5 system locking compression plate (top) and 4.5 system locking compression plate (bottom)

Fig. 22 Reconstruction plate, commonly called a recon plate in short

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224 Fig. 23 Reconstruction plate being bent to fit the shape of a bone. Useful for fixation of clavicle and pelvis

Fig. 24 Various anatomical plates, from left to right, olecranon plate, lower radius plate, lower ulna plate, proximal humerus (PHILOS) plate, medial lower tibial plate, and lateral lower tibial plate

Fig. 25 Calcaneal plate

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Conclusion The operative treatment of the fractures using plates and screws is a standard successful technique. It is very important to know that plates and screws must be of the same material to prevent corrosion of the implants. Absolute stability is when constructs heal with primary bone healing. Compressing together the main fragments of a single plane fracture can result in absolute stability. Plates can be used in many indications and in several ways on the bone. The periosteal blood supply is important for bone healing, and this periosteum must be preserved to promote healing. Plates are available in 316 L stainless steel and titanium alloys. Biodegradable plates and screws using poly-L-lactic acid and polyglycolic acid are being tried to avoid the necessity of implant removal. Ongoing experimental results are encouraging.

References 1. Battula S, Schoenfeld A, Vrabec G, Njus GO. Experimental evaluation of the holding power/ stiffness of the self-tapping bone screws in normal and osteoporotic bone material. Clin Biomech. 2006;21:533–7. 2. Augat P, von Rüden C. Evolution of fracture treatment with bone plates. Injury. 2018;49:S2–7. 3. Uhthoff HK, Poitras P, Backman DS. Internal plate fixation of fractures: short history and recent developments. J Orthop Sci. 2006;11:118–26. 4. Li J, et al. Materials evolution of bone plates for internal fixation of bone fractures: a review. J Mater Sci Technol. 2020;36:190–208. 5. Key JA, Reynolds FC. Contact splints Eggers vs. standard bone plates in the fixation of experimental fractures. Ann Surg. 1953; https://doi.org/10.1097/00000658-195306000-00018. 6. Bagby GW, Janes JM. The effect of compression on the rate of fracture healing using a special plate. Am J Surg. 1958;95:761–71. 7. Roberts TT, Prummer CM, Papaliodis DN, Uhl RL, Wagner TA. History of the orthopedic screw. Orthopedics. 2013;36:12–4. 8. Eggers GWN, Shindler TO, Pomerat CM. The influence of the contact-compression factor on osteogenesis in surgical fractures. J Bone Joint Surg Am. 1949;31A:693–716. 9. Perren SM. Basic aspects of internal fixation. In: Manual of internal fixation. Berlin/Heidelberg: Springer; 1991. p. 1–158. https://doi.org/10.1007/978-3-662-02695-3_1. 10. Frigg R, Frenk A, Wagner M. Biomechanics of plate osteosynthesis. Tech Orthop. 2007;22: 203–8. 11. Seybold D, Citak M, Königshausen M, Gessmann J, Schildhauer TA. Combining of small fragment screws and large fragment plates for open reduction and internal fixation of periprosthetic humeral fractures. Int J Shoulder Surg. 2011; https://doi.org/10.4103/0973-6042. 91004. 12. Yu Z, Zheng L, Zhang Y, Li J, Ma B. Functional and radiological evaluations of high-energy tibial plateau fractures treated with doublebuttress plate fixation. Eur J Med Res. 2009;14:200.

Conventional Orthopaedic Plating

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interfragmentary Screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neutralization Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compression Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Benders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

The primary aim of fixation of fracture is to make the fractured bone stable, to promote healing, and to restore function of the injured extremity. Conventional bone plates were once in common usage and are made of stainless steel 316 L grade. Plating provides secure fixation when the required number of cortices are held by using screws depending on the size of the bone. Conventional plating involves plating with or without interfragmentary screw(s). Keywords

Conventional plate · Interfragmentary screw · Neutralization · Plate bender

Introduction The primary aim of fixation of fracture is to make the fractured bone stable, to promote healing, and to return to function of the injured extremity [1]. S. N. Bhat (*) Department of Orthopaedics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Udupi District, Karnataka, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_13

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Conventional bone plates were once in common usage are made of stainless steel 316 L grade, which is strong, cheap, and easy to manufacture. However, stainless steel plates do not tolerate stress reversals. A process known as “passivation” using a light coat of a protective layer of nitric oxide on stainless steel implant prevents crevice corrosion in vivo. Hence it is essential that this protective layer is not damaged before the implant is inserted. Stainless steel contains nickel, which can cause an allergic reaction to some individuals. Aikawa [2] reported open reduction and conventional plate fixation of radius and ulna fractures in miniature dogs as an effective method. An in vitro study by Bruce [3] did not demonstrate any differences between performance of Dynamic Compression Plate and Locking Compression Plate construct while testing for acute failure. Plating provided secure fixation when the required number of cortices are held by using screws depending on the size of the bone. Forearm bones require at least 4 cortices’ hold, humerus requires hold of 6 cortices, whereas femur requires 10–12 cortices hold on each side of the fracture. Conventional plating involves plating with or without interfragmentary screw(s). An interfragmentary screw is put to achieve compression at the fracture site to achieve absolute stability.

Interfragmentary Screw This technique is used when the fracture is a long oblique or a spiral fracture. In a typical case, the fracture is reduced with the help of two bone holding forceps and kept reduced. A drill hole is made in the near cortex using a 3.2 mm drill bit perpendicular to the fracture site. A 3.2 mm drill guide is passed through the drill hole, and the far cortex is drilled using a 2.5 mm drill bit. The depth of the screw hole is measured. The distant cortex hole is tapped using a 3.2 mm tap. If needed, the near cortex can be counter-sinked to the shape of the undersurface of the screw head. A 3.5 mm cortical screw of measured length is passed from the near cortex toward the far cortex. As the screw is tightened, it achieves compression at the fracture site (Fig. 1).

Neutralization Plate A plate of adequate length protects the above construct by putting screws through the centre of the holes of the plate, i.e., without “loading”. This plate is called a neutralization plate. The plate used can be a Müller’s plate, a dynamic compression plate or even a locking compression plate (Fig. 2). Fig. 1 Interfragmentary screw to achieve compression at the fracture site

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Fig. 2 Interfragmentary screw protected by a neutralization plate

Compression Plate Plates allowing dynamic compression in the axial plane have resulted in a revolution in fixation of fracture [4]. When load is applied to the plate for achieving compression at the fracture site after the reduction of the fracture, it is called a compression plate. Such plating can be used in transverse or short oblique fracture. How to achieve compression with a plate? Before the invention of the dynamic compression plate by AO, surgeons used Müller’s compression device (Fig. 3). Müller’s plate has round holes and slots at either end. After the fracture is reduced, bone is held with the plate using a pair of bone holding forceps. One end of the plate is fixed to the bone using one cortical screw. On the other end of the plate, the compression device is attached to the slot and fixed to the bone using a cortical screw. The threaded portion in the compression device is tightened to achieve 1–2 mm of compression at the fracture site. A cortical screw is applied to the plate on the same side of the compression device. (Fig. 4) Once the screw is tightened, the compression device is removed. Then remaining all screws are applied. A similar effect can be achieved using the dynamic compression plate (DCP). A DCP has oval holes which are designed in such a way that the screw head slides in the screw hole. It is designed such that the screw holes permit the screws to slide toward the middle of the plate (Fig. 5a, b, c). The fracture is reduced, held with two bone-holding forceps with a dynamic compression plate underneath. The middle of the plate should be over the fracture site in an even holed plate. In an odd holed plate, one should be careful to note the sliding direction of the holes. The two holes have more distance between them than the remaining holes. A drill hole is made into the hole adjacent to the fracture site using an eccentric drill guide. The arrow in the guide is directed toward the fracture site (Fig. 6a, b, c). The depth is measured, and the drill hole is tapped to create threads. The measured length of the cortical screw is applied, but not tightened fully. Similarly, on the other side of the fracture, close to the fracture, a drill hole is made using the eccentric drill guide with the arrow pointing to the fracture site. The drill hole is measured and tapped. A screw of measured length is put. Now sequentially, the bone holding forceps are loosened on one side (but not removed), and the screw is tightened. The plate slides to achieve 1 mm compression on that side (Fig. 7a, b). The bone holding forceps are tightened, and the other one is loosened. Now the other screw is tightened to achieve one more mm compression. Now the remaining holes of the plate are drilled using the neutral drill guide, tapped and fixed with

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Fig. 3 Müller’s compression device

Fig. 4 Achieving compression using the Müller’s compression device. Initial compression occurs at the far cortex

screws (Fig. 8a, b, c). The bone-holding forceps are released. In this manner, a maximum of 2 mm compression can be achieved. The compression effect can also be achieved to some extent by pre-bending the plate (Fig. 9a, b, c). Plate fixation enables direct healing of the fracture fragments by securing the fracture fragments and maintaining alignment. However, being a highly invasive approach, it results in an immense amount of biologic stress around the fracture site.

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Fig. 5 (a) Dynamic Compression Plate. Note the gap between the two middle holes (white arrow) and the gap between side holes (black arrow). (b) Picture showing the design of the screw holes in DCP. (c) Section of a hole of DCP. Red interrupted line shows the sliding of the screw as it is tightened

Fig. 6 (a) DCP with the eccentric guide and a drill bit in place. (b) DCP with the eccentric guide and drill bit in place showing the eccentric location of the drill bit in the screw hole. (c) A section of the hole of DCP with a screw in situ being loaded eccentrically

In addition, there can be delayed union, infection, and poor fixation in osteoporotic bone. In contrast to conventional plating, the newer locked plates provide some flexibility inducing the formation of periosteal callus through interfragmentary motion [5]. Soileau [6] reviewed several research papers which compared the biomechanics of conventional and non-locked plates on osteoporotic fractures.

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Fig. 7 A section of a DCP hole showing sliding of the plate as the screw is tightened

Fig. 8 (a) DCP with the neutral guide and a drill bit in place. (b) DCP with the neutral guide and the drill bit in place showing the central location of the drill bit in the screw hole. (c) A section of the hole of DCP with the screw in situ put in the neutral position

Though many advantages of the newer locking plates have been described, there are still several indications for conventional compression plating [7, 8]. In a study of humeral fractures, plating had significant risk of infection and radial nerve palsy. There was no significant difference for non-union and revision rate when compared to nails [9]. Another meta-analysis by Ouyang et al. [10], describes both plating and nailing giving similar results on humeral shaft fractures.

Plate Benders Bone plates are bent in two situations. 1. Pre-bending: Produces concavity compression of the far cortex. 2. To contour bone plates to fit the anatomical shape of the bone.

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Fig. 9 (a, b, c) Figures showing how a prebent plate achieves compression at the fracture site on tightening the screws

Fig. 10 A large plate bender, pressing type

Different types of plate benders are available. (Figs. 10 and 11a, b). A bone plate should be bent in a single direction. Overbending and then correcting results in stress reversal, damaging the crystalline structure of the plate, weakening it. Hence the fatigue life may be reduced.

Conclusion Conventional plates can act in two different ways: compression providing absolute stability and splinting providing relative stability. While applying the principles of plate fixation, proper preoperative planning is essential. A mixture of two principles/ methods of fixations are to be avoided.

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Fig. 11 Bone plate benders. We need two of them to bend a plate

References 1. Taljanovic MS, Jones MD, Ruth JT, Benjamin JB, Sheppard JE, Hunter TB. Fracture Fixation. Radiographics. 2003;23(6):1569–90. https://doi.org/10.1148/rg.236035159. 2. Aikawa T, Miyazaki Y, Shimatsu T, Iizuka K, Nishimura M. Clinical outcomes and complications after open reduction and internal fixation utilizing conventional plates in 65 distal radial and ulnar fractures of miniature- and toy-breed dogs. Vet Comp Orthop Traumatol. 2018;31(03):214–7. https://doi.org/10.1055/s-0038-1639485. 3. Bruce CW, Gibson TWG, Runciman RJ. A comparison of conventional compression plates and locking compression plates using cantilever bending in an ilial fracture model. Vet Comp Orthop Traumatol. 2014; https://doi.org/10.3415/VCOT-14-01-0001. 4. Uhthoff HK, Poitras P, Backman DS. Internal plate fixation of fractures: Short history and recent developments. J Orthop Sci. 2006; https://doi.org/10.1007/s00776-005-0984-7. 5. Augat P, von Rüden C. Evolution of fracture treatment with bone plates. Injury. 2018;49:S2–7. https://doi.org/10.1016/S0020-1383(18)30294-8. 6. Soileau R, Cartner J, Zheng Y. Locked versus conventional plate-screw fixation in osteoporotic bone: a review. Tech Orthop. 2007;22(4):247–52. https://doi.org/10.1097/BTO. 0b013e31815dccdd. 7. Gardner MJ, Helfet DL, Lorich DG. Has locked plating completely replaced conventional plating? Am J Orthop (Belle Mead). 2004; 8. Fulkerson E, Egol KA, Kubiak EN, Liporace F, Kummer FJ, Koval KJ. Fixation of Diaphyseal fractures with a segmental defect: a biomechanical comparison of locked and conventional plating techniques. J Trauma Inj Infect Crit Care. 2006;60(4):830–5. https://doi.org/10.1097/01. ta.0000195462.53525.0c. 9. Dai J, Chai Y, Wang C, Wen G. Dynamic compression plating versus locked intramedullary nailing for humeral shaft fractures: a meta-analysis of RCTs and nonrandomized studies. J Orthop Sci. 2014; https://doi.org/10.1007/s00776-013-0497-8. 10. Ouyang H, Xiong J, Xiang P, Cui Z, Chen L, Yu B. Plate versus intramedullary nail fixation in the treatment of humeral shaft fractures: an updated meta-analysis. J Shoulder Elb Surg. 2013; https://doi.org/10.1016/j.jse.2012.06.007.

Orthopaedic Locking Plates

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History of Locking Plates [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics of Locking Bone Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of Different Forces on a Locked Screw-Plate Construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bending and Axial Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Optimized Plate Anchorage with Divergent or Convergent Locked Screws . . . . . . . . . . . . . . . . . . Working Length of a Screw (Fig. 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unicortical Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hazards of Unicortical Insertion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications of Bicortical Screw Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flexible Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Far Cortex Locking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load Distribution in FCL Screws [7] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Progressive Stiffness [8] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parallel Interfragmentary Motion [8] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Length and Plate Working Length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Screw Type and Placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Choosing the Number of Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Choosing the Position of Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate-Screw Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Choosing the Material of Implants: Stainless Steel or Titanium . . . . . . . . . . . . . . . . . . . . . . . . . . . Effect of Screw Position on Axial and Torsional Stiffness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics of Locking Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Countersink . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Runout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Screw Thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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© Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_14

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Core Diameter (Fig. 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thread Diameter (Fig. 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics of Locking Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Locking Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fixed-Angle Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Variable-Angle Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Undersurface of a Locking Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications of Locking Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Contraindications of Locked Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disadvantages of Locked Internal Fixator Plate (LIFP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Plating long bone fractures is a practice with a long history, evolving from basic techniques to today’s advanced plating systems. Anatomic reduction using dynamic compression plates has traditionally been considered the gold standard for many fractures. However, minimally invasive approaches combined with biologically friendly internal fixation have now become accepted methods for treating complex fractures. Orthopaedic literature has shown advantages when comparing locking plate techniques to traditional compression plating techniques in certain situations. Each system has its own set of advantages and disadvantages. Non-locking plates have been used for a long time until we recognized their limitations in certain situations, such as intraarticular and periarticular fractures, osteoporotic fractures, highly comminuted fractures, and periprosthetic fractures. The biomechanical properties of locking plates have distinguished them and defined their clinical use compared to traditional plates. A thorough understanding of these properties will assist users in choosing the appropriate construct when faced with a difficult fracture. Compression plating requires absolute stability for bone healing, whereas locking plates function as “internal fixators” with multiple anchor points, similar to external fixators. This type of fixed-angle device converts axial loads across the bone into compressive forces across fracture sites, minimizing gap length and strain. In contrast to conventional DCP, locking plates promote secondary bone healing through increased callus formation. Further promotion of callus formation occurs when biologically friendly surgical approaches are combined with locking plate “internal fixators”. As the indications for fracture surgery increase, there is now more scope for using such implants. Additionally, as we encounter more difficult metadiaphyseal and osteoporotic fractures, locking plates are gaining importance in orthopaedic fracture fixation. The literature demonstrates low rates of non-union and overall complication rates with locking plates in challenging metaphyseal and diaphyseal fractures. Anatomic reduction of the articular surface remains of paramount importance. Hybrid techniques that combine the benefits of compression plate fixation with the biological and biomechanical advantages of locking plates represent the most advanced evolution in the plating system for fractures. Designs

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in screws, screw holes, locking mechanisms, and plate morphology, as well as plating techniques are continuously evolving, and many more clinically useful changes are yet to come in the future. Keywords

Locking plates · Locking screws · Screw threads · Biomechanics · Plate-screw construct · Plate stiffness · Axial load · Torsional load

Introduction Orthopaedics has advanced to a great extent in all fields and fracture fixation is not an exception. Thanks to Parren, who developed dynamic compression plate, which allowed rigid fixation of fractures allowing early joint movements and mobilization. Since the advent of surgical fracture care, orthopaedic surgery has seen many great advances. Early concept of rigid fixation although had many advantages but it sometimes sacrificed the biology of fracture healing leading by compromising blood supply to the bone leading to resorption of fractures ends resulting in nonunion. In 1990s, a Switzerland surgeon, Davos developed a technique of locked plating, which is considered as a revolution in fracture fixation. Since the advent of locked plating, it has become the part of our essentials in fracture fixation tools and techniques. However, the concept of the locking plate should be well understood by the surgeons and it should be used in justifiable manner. Locking screws have threaded heads which locks with the threads of the plate on tightening providing a fixed-angle construct which is less prone to loosening or toggling when compared with non-locking constructs. In an unlocked plate, the screw is not formally attached to the plate and toggling or loosening of the screw can occur through bone. First-generation locking plates are designed in a way that compels us to insert a locking screw in a fixed axis. With the advent of current variable-angle locking plates, surgeons have the freedom to use screws in different angles which sometimes proves very beneficial as in intra-articular and metaphyseal fractures. Several locking mechanisms and hole designs are evolving day by day making fracture fixation more surgeon friendly, and biomechanically superior and so ensuring better results and less failure on physiological loading.

History of Locking Plates [1] It is the shift in concept in true sense, and not an implant, which lead us to shift from non-locking to locking plates. Monocortical fixator by Carl Hansman in 1886 is supposed to the earliest move in locking plate evolution. Gradually Litos system (1974), Zespol system (1982), and finally the foundation of current locking plate system 1995) came into the practice. Then concept was developed by Patrick Sürer

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with the Surfix system independently, unchanged since its beginnings, and then by the AO through many stages. First of all, in the line was the point contact fixator (PC-fix) (2005) and the LISS (2001) and then followed the new generation locking compression plate (LCP) with all its versions. The Schuli locking nut systems (1998) was a completely new system where a common screw could be locked in a plate that could be qualified as “normal”. Varieties of further evolution in plate design, locking hole configuration, locking mechanism and locking screw designs, and biomechanics have taken place. During the flow of different topics, we will come across a few of them.

Biomechanics of Locking Bone Plates Locking plates are made of stainless steel (ASTM Fi38) or titanium alloy (Ti-GAI-4V). Metals, because of their elastic properties, work well for internal fixators, which function like a splint. Plates, as splints, act a devise that reduces the elastic deformation of the bone under applied load. To increase the flexibility, the dimensions of the metal implants is reduced deliberately, which in turn results in favourable outcome. Usually, the plate that is used is slightly reduced in size and made of an easily deformable metal, such as titanium. Hypersensitivity, rather an uncommon phenomenon after plating, is generally associated with a very high concentration of products of galvanic, fretting, and crevice corrosion in the surrounding tissues. The corrosive behaviour of metals reduces the fatigue life of an implant in a biological environment. The locked internal fixator plate is analogous to the external fixator where threaded head of screw acts like a Schanz pin and is locked in the threaded hole in a plate (Fig. 1). The locked units are axially and angularly stable. When this construct bears physiological loads, the forces are transferred from one segment to another through the locked screws. The locking screw just connects the plate with the bone and unlike a conventional plate, it does not compress the plate onto the bone. Unlike compression screws, locking screws are mostly exposed to banding loads and less to tensile forces. For this reason, the core diameter of these locking screws is thicker than that of conventional bone screws. The plate with locked screws forms a monoblock construct. Such fixation is less dependent on the quality of the bone and all the anatomic anchoring regions. LIFP acts like an implanted external fixator (internal external fixator). It represents a novel, bio-friendly approach to internal fixation [2]. It stimulates abundant callus formation by bone healing by secondary pattern. Widely spaced locked screws behaving as external fixator pins and the plate functioning as the connecting bar are placed extremely close to the mechanical axis of the bone. This closeness increases stability compared with the monoplaner external fixator. In conclusion, a locking plate system causes the least vascular damage in comparison to intramedullary nailing or conventional plating.

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Fig. 1 (a) Showing analogy between unilateral external fixator and unicortical locked plate construct. (b) A locked internal fixator plate is analogous to the pin-clamp-road complex of an external fixator

Effect of Different Forces on a Locked Screw-Plate Construct It responds differently than a conventional non-locking screw-plate assembly.

Bending and Axial Load A locked plate acts as a fixed-angle device. It controls the axial orientation of the screw to the plate, so enhancing screw-plate-bone construct stability by creating an intrinsically stable single-beam construct. It converts shear forces to compressive forces at the screw-bone interface; this force conversion is beneficial in fracture fixation because the cortical bone is stronger against compressive loads than against shear loads (Fig. 2). Locked plates have inherent angular and axial stability which further improves fixation. Fixation rigidity of an external fixator is a function of the Schanz pin (its material, length, and diameter) and dimensions of the fixator bar, analogous to a locked screw and plate. The short screw length (10–15 times shorter than for external

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Fig. 2 Effect of bending and axial loads on locked plate design. (a) Unloaded construct. (b) Bending load applied. A locked screw does not loosen and resists pullout (c) Failure with pure pullout (although rare) requires all the screws to fail simultaneously. (d) An axial load applied. A locked screw does not loosen; it experiences the majority of the load perpendicular to its axes

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fixators) in the locked plate construct substantially increases its rigidity. Stability across the fracture becomes a function of the mechanical properties of the plate and the amount of load applied. The locking of the screw in the locking plate does not require any axial preloading of the screw and so the relative position of the plate with the bone stays unchanged and the stable anchorage is achieved. This is also why we do not need to contour the locking plate exactly to the bone shape.

Optimized Plate Anchorage with Divergent or Convergent Locked Screws The locked screws impart angular stability to the plate similar to an angled-blade plate. The toggle seen in the conventional plate is absent in the locked plate construct which prevents loss of fracture reduction. The pullout failure mechanism of a screw is by shearing as the pullout force exceeds the pullout resistance, a screw tears out a bone “cylinder” proportional to the size of the screw diameter. The screws inserted in divergent mode provides several times increased pullout strength of the construct. This pullout strength is even more in locking plate systems because the fixed-angle stable divergent construct offers a larger resistance to the pullout forces. It does not toggle to align with the pullout forces also and so produces extremely large volume of pullout resistance (Fig. 3).

Working Length of a Screw (Fig. 4) The working length or fixation strength of a screw is dependent on the thickness of the bone cortex; the thicker the cortex, the longer is the working length. The working length depends on the total number of engaged threads; it does not matter whether one or both of the cortices are engaged by the screw. A satisfactory working length is

Fig. 3 Bending the plate allows the insertion of locking screws divergently or convergently which in turn improves the pullout resistance of the construct

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Fig. 4 The working length of a unicortical screw is longer in healthy bone (a) than in porotic bone (b). When a bone is loaded with torque, a healthy bone (c) has more resistance than a porotic bone (d) to the applied torque. (e) In all situations, bicortical screw fixation gives the maximum working length

achieved when a total of three to four threads are fully engaged in the bone cortex. In all situations, the bicortical purchase gives maximum working length.

Unicortical Screws In a LIFP construct, the screws lock into the plate and the plate remains in closed proximity to the bone; unicortical screws can be used without compromising the strength and stability of the construct. This locked unicortical screw functions like a conventional bicortical screw, but it requires a strong anchorage for proper function

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Fig. 5 Self-drilling selftapping locked screw

within a cortex of normal thickness. Hence, it is inefficient in a metaphyseal cancellous bone that has minimal cortical thickness. Unicortical screws are easier to place percutaneously and allows use of self-drilling, self-tapping screw. A self-drilling and self-tapping screw is made by reducing the length of threaded portion and adding a drill and a tap section to the screw tip (Fig. 5). The benefits of using these screws are that the surgical technique is simplified, screw length measurement is not necessary, smaller inventory is needed as screw need not to be available in small increments, and self-tapping screw tip cuts exact thread profile into the bone that improves screw-bone anchorage. It also prevents damage to the intramedullary blood supply. Although unicortical screws can be used in diaphyseal fractures, its holding capacity is less than half of a bicortical screw. The number of unicortical screws required depends on their spacing, their loading, and the quality of the bone. Unicortical application is no longer preferred, and in a poor-quality bone, bicortical engagement is recommended. As demonstrated in Fig. 4, the advantages of bicortical fixation with regard to the screw working length far outweigh the advantages conferred by a healthy cortical bone. Bicortical screws tolerates loading better then unicortical screws as these have increased working length as well as additional bone purchase. Bicortical locked screws are preferred in places where high torsion loading is expected. It also provide a greater interface and therefore greater stability to the construct.

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Fig. 6 Length discrepancies in the use of unicortical screws. (a) In bones with small diameters, the tip of a self-tapping screw can contact the far cortex before the head has engaged in the plate hole, resulting in damage to bone threads in the near cortex. (b) So, in such a situation, the far cortex should be drilled and (c) a bicortical self-tapping locked screw should be inserted

Hazards of Unicortical Insertion Even the shortest possible self-tapping unicortical locked screw would destroy the bone threads if the screw tip touches the far cortex before the screw firmly locks in the plate hole (Fig. 6); to avoid the problem, it is safer to measure the correct length of the screw after drilling. A fixed-angle unicortical locking screw may have a precarious hold in the cortex (Fig. 7). The differences in the sticking-out length of self-drilling and self-tapping screws are very important to safeguard the safety of neurovascular tissues. A self-drilling screw should not protrude beyond the bone, while a self-tapping screw needs to protrude up to the first complete thread to obtain a good purchase on the far cortex (Fig. 8).

Indications of Bicortical Screw Fixation Although bicortical screw fixation should be preferred whenever in doubt, there are some must-use situations [3]. • Osteoporotic bones • Bone with thin cortex

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Fig. 7 (a) Placing a unicortical screw in an eccentrically placed plate leads to a small sector cortical purchase of the screw. (b) A better purchase is gained by inserting a bicortical self-tapping screw. (c) An even better alternative is to use a conventional bicortical screw at an angle to gain maximum trajectory

Fig. 8 (a) A self-drilling self-tapping screw should be used as a unicortical screw only to avoid damage to the neurovascular structures beyond the far cortex. (b) The self-tapping screw has a relatively smooth tip and is safer in terms of neurovascular damage and so to provide good anchorage its tip should protrude slightly beyond the far cortex

• Anticipated high torsional forces during rehabilitation as in the case of preoperative stiff joints • Short main fragment

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Small medullary diameter Replacement of a cortical reduction screw with a locked screw Accidental damage to bone thread in the near cortex Multiple attempts to insert a locking screw

Flexible Fixation A locking plate-screw construct has a superior hold in an osteoporotic bone but it has a stiffer construct as compared with a conventional screw plate construct, reduces interfragmentary movement, and discourages callus formation. So, a flexible construct has been deployed which is known as “bridging plating” to overcome these shortcomings and to encourage callus formation leading to secondary bone healing. Although even with bridging construct, callus formation is deficient, inconsistent, and asymmetrical and causes delayed union, non-union, and late implant failure [4].

Far Cortex Locking Two types of far cortical locking screws are available – (a) Zimmer’s MotionLoc Screw and (b) dynamic locking screw of the AO foundation (Fig. 9). Flexible shaft of FCL screw promote micromotion at the fracture site. The FCL screw fits into the plate and locks into the far cortex. The shaft of FCL screws is devoid of any threads. It is a new variety of locking screws that induces and enhances parallel interfragmentary movement at the near and far cortex (Fig. 10). An FCL construct resembles an external fixator where pins are secured in the far cortex and rod has been applied close to the bone surface. The working length of FCL screws approximates that of the external fixator pins. The FCL construct reduces the stiffness of a locked plating construct by 80–88% and actively promotes callus formation similar to an external fixator [7].

Load Distribution in FCL Screws [7] Load is evenly distributed between FCL screws to lessen stress risers at the last screw (end screw; Fig. 11). Standard locking plates do not transmit load by plate-tobone compression but pass on the load through fixed-angle screws. This mode of load transfer induces stress concentration at the screw-bone interface, particularly at the outermost locking screw; in a porotic bone, this stress concentration increases the fracture risk at the end of the plate. When FCL screws are used in a construct, there is no stress riser at the outermost screw; a stress riser always exists in a standard locked plate construct.

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Fig. 9 FCL uses a flexible shaft of the screw to promote micromotion at the fracture site. (a) Zimmer’s MotionLoc ® Screw [5] is used only in the diaphyseal fractures where screw purchase is obtained in the far cortex. These should not be used in the metaphysis or epiphysis. (b) Dynamic locking screw of AO foundation [6] may be used in metaphysis as well as in diaphyseal. During both above screw insertions, it is recommended to keep the plate elevated from the bone surface using two suitable temporary spacers. Two cautions to be taken – first, the plate should not be elevated more than 3 mm, and, second, standard locking screws should not be inserted in the same fragment where FCL screws are installed

Progressive Stiffness [8] FCL constructs shows biphasic stiffness where initially low stiffness is exhibited through the flexible screw shafts and then gradually stiffness increases when the load rises. Clinically, this initial low stiffness of the FCL construct allows more interfragmentary motion (IFM) in the early healing phase when the patients are allowed partial load bearing. In an eventuality of an elevated loading in the initial healing phase, the near-cortex support protects the fracture site and prevents it from excess motion.

Parallel Interfragmentary Motion [8] An axially loaded locked plate in a bridging construct undergoes flexion (i.e., elastic plate bending). This flexion facilitates interfragmentary motion because the plate

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Fig. 10 (a) MotionLoc far cortical locking – reducing the diameter of the shaft increases the working length of the screw. (b) Dynamic locking screw for far cortical locking has a pin-sleeve arrangement that permits slight deflection and stimulates micromotion at the fracture site within the angular stable fixation in the bone plate

acts as a hinge and permits interfragmentary motion in a gradually increasing quantity toward the far cortex opposite the plate. The moment pattern leads to asymmetrical gap closure, whereby interfragmentary motion at the near cortex is suppressed by five times leading to less callus formation at the near cortex. This interfragmentary movement has a large component of shear motion and less of axial motion [9]. In an FCL construct, the FCL screw’s flexible shafts act as cantilever beams and undergo S-shaped flexion to induce near-parallel IFM at both the cortices with true axial motion and no shear motion. FCL construct induces parallel interfragmentary movement by cantilever bending of FCL screws leading to symmetrical abundant callus formation at both near and far cortices.

Plate Length and Plate Working Length The actual plate length depends upon the fracture pattern and the treatment principle to be employed for the particular fracture. Plate length is also based on the intended biomechanical behaviour at the fracture site.

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Fig. 11 (a) Showing equal flexion of each screw and equally distributed strain along the entire working length when FCL screws are used. (b) Showing focused strain closed to the near cortex in standard locking plate-screw construct

To treat a multifragmentary fracture, relative stability is desirable and flexible splinting without compression is the method of choice. This situation needs a plate twice or thrice the fracture length. The same calculation will apply; a simple transverse fracture has a short length which is treated with compression where we recommend keeping the plate length 8–10 times longer than the fracture length. The plate length and screw placement and thus the plate span width and the plate-screw density determine the loading condition of the plate [10]. The plate span width is defined as the plate length divided by fracture length (Fig. 12). It is recommended to be twice to thrice in a comminuted fracture and 8–10 times the length of a simple fracture. Plate-screw density is defined by the number of screws divided by no. of screw holes. Plate-screw density should be calculated for each bone segment and for the entire bone separately [11].

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Fig. 12 Calculating the plate span width and plate-screw density for mechanically stable fixation of a multifragmentary diaphyseal fracture of the lower limb. (For the method of calculation, please refer to the text)

It is known that the axial stiffness of a construct is reduced when a shorter plate is used in place of a long one, with the same number of screws; therefore, long plates should be used to optimize axial stability. The torsional rigidity of a construct is not compromised by any change in the plate length. The plastic deformation of the plate is most dependent on the screws closest to the fracture site and so when these screws are removed, plastic deformation decreases significantly as the working length is increased and more flexibility is tolerated (Fig. 13). The working length of a plate refers to the distance between the two screws closest to the fracture on either side. It determines the elasticity of the fracture fixation and distribution of induced deformation caused by external load, a factor more important for the durability of the implant. A longer working length of a plate distributes the deformation over a longer distance and avoids the undesirable plastic deformation. As a result, it avoids breakage of an overloaded short plate section. A spanning distance of three empty screw holes over the fracture line ensures an elastic construct that distributes the induced stress over an adequate plate length.

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Fig. 13 Relation between working length and strain at the level of the fracture. (a) Leaving three to four plate holes empty increases the working length and (b) too stiff construct leading to the short working length resulting in breakage of the plate

Fracture gap size is also important factor for plate failure. As the working length increases over a fracture gap size of 6 mm or more, the plate fatigues earlier. This trend is not seen when the fracture gap size is 1 mm or less [12].

Screw Type and Placement Integrated holes of LIFP can accept four types of screws as follows: 1. 2. 3. 4.

Conventional cortical screws – allows variance in insertion angle. Conventional cancellous screws. Locking self-drilling self-tapping screws – used only as unicortical screw. Locking self-tapping screws – for first-generation locking plates, they must be inserted perpendicular to the screw hole (insertion angle should not exceed 5 degrees) and so the use of a sleeve or another aiming device is recommended. The current generation locking screws can be inserted at an angle within the 15-degree base radius of a cone as the plate hole permits the drilling of variable angle holes up to 15 degrees’ deviation from the normal trajectory of the locking hole.

Choosing the Number of Screws For safety, the general recommendation is for the insertion of a minimum of three screws in each main fragment of bone. Stoffel et al. [13] recommended at least three to four screws on each side of the fracture of the humerus and forearm bones because of rotational loads.

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Choosing the Position of Screws Induced implant deformation is defined by the strain-dependent closing and opening of a fracture gap. The longer distance between the two screws on either side of the fracture ends distributes the deformation forces over a longer distance. Ultimately, it reduces the chances of plastic deformation of an overloaded, short segment of plate [13]. When bridging a large gap, screws should be closed to the fracture line because such placement decreases the stresses on the plate and protects it from fatigue failure. Conversely, when bridging a small gap, screws should be moved away leaving two to three screw holes empty which helps to distribute the induced stress over an adequate plate length resulting in less chances of fatigue failure [14].

Plate-Screw Density It is calculated as the number of screws inserted divided by the number of screw holes in the plate. In simple and multifragmentary fractures, it should be 0.4–0.3 and 0.5–0.4, respectively.

Choosing the Material of Implants: Stainless Steel or Titanium A stainless steel implant is under higher stress than a titanium implant when supporting a small fracture gap of 10 degrees in older children 4. Monteggia fractures and radial head fractures

Steps Flynn and Jones suggested that the radius should be fixed first [18], while Myers et al. proposed starting with the bone with the greatest deformity [19]. 1. The ulnar nail requires only a prebend of about 10 degrees, as the bone is almost straight. This allows three-point fixation of the nail and also acts as a counter for the prebend in the radius nail. 2. The radius nail is usually prebent to 30 degrees. 3. The more difficult bone (often the radius) is nailed first. 4. Turn the tips of both nails towards each other to spread the interosseous membrane. 5. Retrograde nailing of radius dorsally and antegrade nailing of the ulna through the posterolateral part of the olecranon is the preferred technique (Figs. 15 and 16). 6. If closed reduction fails for more than 3 attempts, the fracture site must be opened, in order to avoid compartment syndrome. A “10-minute rule” should be followed

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Fig. 14 Preoperative radiograph, intraoperative C-arm picture and postoperative radiograph of shaft of humerus fracture treated with unipolar retrograde elastic nails

and if the surgeon is unable to navigate the nails across the fractures site in 10 min, open reduction must be considered [20]. In dorsal radial approach, EPL rupture has been reported due to injury with the sharp nail end. In a lateral approach to the radius, the superficial radial nerve should be identified and protected (Fig. 17). Delayed union or even non-union (most

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Fig. 15 Anteroposterior and lateral radiographs of forearm showing united fracture of both bones of the forearm after retrograde radius and antegrade ulna elastic nailing

Fig. 16 Preoperative and postoperative radiographs of forearm showing retrograde radius and retrograde ulna elastic nailing

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Fig. 17 Insertion of radial nail between the first and second extensor interval (Listers tubercle) with direct vision of structures

commonly in the middle 1/3rds of the ulna, which has a “watershed-zone” for the interosseous circulation) is an existing complication. In children less than 9 years of age, we can accept complete displacement, 15 degrees of angulation and 45 degrees of malrotation. In children 9 years of age and older, we can accept bayonet apposition, 30 degrees of malrotation and acceptable angulation of 10 degrees [21]. However, these criteria should always be individualized, being more lenient for younger patients and more distal fractures. Early hardware removal, open reduction and open fractures are associated with an increased chance of refracture.

Radial Neck An elastic nail of 1.5–2.5 mm is used. The nail is curved in its middle portion and is advanced retrograde all the way to the radial neck. The elbow is positioned in extension, the nail tip is passed into the radial head and the nail is rotated by 180 , causing reduction of the fragment (Fig. 18) [22]. An immobilization of 2 weeks, followed by ROM exercises, follows. Implant removal is performed anywhere after 8 weeks, after fracture union.

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Fig. 18 Illustration of Metaizeau technique for reduction of displaced radial head fracture

Clavicle The principle is three-point fixation with single curved nail.

Indications 1. 2. 3. 4.

Open fractures Polytrauma More than 2 cm shortening / displacement Floating shoulder

Relative Contraindications 1. Segmental fractures 2. Grossly comminuted fractures

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Steps The clavicle is a curved bone with a narrow medullary diameter, especially in the middle 1/3 of the clavicle (average IM diameter is 6.7 mm). A 2.0 mm or 2.5 mm nail is usually used. Entry point is from the anterior cortex of the clavicle, medially (1 cm lateral to the sternoclavicular joint). The nail is passed across the fracture site with gentle oscillating movements under fluoroscopic control (Fig. 19). Open reduction is performed if closed reduction fails. Postoperative care includes a shoulder sling and early mobilization as tolerated. Heavy load bearing is delayed until fracture consolidation. Implant removal is advised after fracture consolidation. TENS leads to a faster fracture healing along with better restoration of clavicular length and lowers the rates of non-union and delayed union in simple mid-shaft clavicle fractures. In comminuted fractures, it is advisable to perform plating instead of TEN when clavicular shortening is significant (>7% length shortening) [23]. Clavicular shortening leads to an increase in the sternoclavicular joint angle, thereby changing the resting position of the scapula and the preload of the muscles of the shoulder girdle. This leads to limitations in overhead motion, pain and weakness.

Fig. 19 Preoperative (a) and postoperative (b) radiographs and intraoperative C-arm picture (c) of TEN for clavicle fractures

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TENS is eligible only in simple fractures and comminuted fractures with moderate (30 degrees in sagittal and > 10 degrees in frontal plane), unstable fractures 2. Age 5–15 years 3. Polytrauma 4. Open fractures

Steps Closed reduction and casting is the mainstay of treatment for these fractures, though plating, K-wire fixation and elastic nailing are also commonly performed when required. Elastic prebent nails provide adequate stability that allow commencement of early mobilization (Fig. 20).

Fig. 20 Preoperative and postoperative radiographs of an angulated little finger metacarpal shaft fracture in a skeletally mature adult, treated satisfactorily with titanium elastic nail fixation. (Adapted from Mohammed et al. [33] under Creative Commons CC BY 2.0 (http:// creativecommons.org/licenses/by/2.0))

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Advantages of elastic nailing include: 1. 2. 3. 4.

Minimally invasive percutaneous technique No disturbance of the joint capsule Accelerated fracture healing and No disturbance of the extensor tendons

While TEN of metacarpal fractures allows cast-free treatment, early postoperative mobilization and rapid return to daily activities, plating is still preferred for displaced multi fragmentary fractures [25].

Ribs The fixation follows three-point fixation principle with a single curved IM nail.

Indications Polytrauma and flail chest.

Relative Contraindication Segmental fractures.

Principles of Fixation Rib fixation can significantly reduce the period of ventilator dependency in a patient with flail chest. Plating, that has been traditionally used, requires extended incisions that lead to more pain and further destruction of the various muscle layers. Kirschner wires often back out or migrate, thereby posing a risk for injury of the surrounding soft tissues and vital organs. The region from fourth to the ninth ribs comprises the largest volume of the entire chest cavity. Fractures in this region can cause severe deformation of the chest wall, especially when combined with flail chest. Rib fractures in this region are suitable for fixation. Fractures on the anterior lateral side can be fixed because injuries in this region usually cause severe chest wall deformation (Fig. 21). The posterior third ribs, especially near the thoracic vertebral spine, do not require fixation. In case of multiple rib fractures, alternate ribs fixation will be adequate to align the rest of the fractured ribs [26].

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Fig. 21 Postoperative oblique radiograph of the chest showing use of TENS for fixation of fractured ribs. (Reproduced from Tarng et al. [26] under Creative Commons CC BY 4.0 (http:// creativecommons.org/ licenses/by/4.0))

Benefits and Limitations TENS Benefits 1. Small incisions and relatively simple instrumentation. 2. Maintenance of length and alignment without violation of the physes/growth plate. 3. Micromotion at the fracture site unique to elastic nailing encourages rapid healing with bridging callus. 4. Preservation of biology allows faster and stronger fracture healing. 5. Percutaneous procedure means less risk of infection and non-union. 6. Other advantages of titanium – higher strength, lighter weight, corrosion resistance and MRI compatibility.

Complications and Failures of TENS The simplicity of TENS should not be construed as a relaxation from following the basic principles of the procedure. Most failures are not failures of implants, but failures of surgical technique. Particular attention is needed on the surgical principles as nowadays the indications are being increasingly widened, with more unstable fracture patterns being treated with this method.

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Failure of the Surgical Principle Prebend TENS work on the principle of three-point fixation, which must be strictly adhered to. Most errors occur from inadequate internal bracing where the nails do not touch the inner surface of the cortex adequately, due to insufficient prebending (Fig. 22). Two nails of the same size and similar prebend should always be used. The circular muscle mantle, along with the elastic forces of the prebent nails, pull the fragments back into an anatomical position. Nail Diameter In scenarios where two nails are used in a single bone (femur, tibia, humerus), each nail should be 40% of the isthmic diameter. Exceptions are the forearm and the clavicle, where only one nail of thickness at least 60% of the isthmic diameter should be used. Too thin nails can lead to axial malalignment or angulation (Fig. 23). Nails of two different diameters can lead to frontal or sagittal plane deformity with potential functional and cosmetic impairment. Insertion Point • Asymmetric insertion points can influence the biomechanics due to differing internal tensions between the nails and thereby lead to deformity. Exceptions are the monolateral/monopolar nailing of the femur for distal metaphyseal femoral fractures and humeral supracondylar and proximal humeral fractures.

Fig. 22 (a) Nails with good contact with the inner cortical layer, (b) Nails with poor contact with the inner cortical layer

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Fig. 23 Anteroposterior and lateral radiographs of femur showing thin titanium elastic nails used for the fixation of the shaft of femur with adequate prebend, also showing corkscrewing of the nails

• Diaphyseal insertion can cause muscle irritation and restricted motion. • Selecting a dorsal insertion point for the distal radius and a radial insertion point for the proximal ulna avoids potential superficial radial nerve and ulnar nerve injuries. • Insertion points too close to the epiphysis can injure the growth plate. • Nails that are too long outside the bone or are bent away from the bone (Fig. 24) can cause severe skin irritation or skin breakdown (Fig. 25). A similar irritation of the ileotibial tract can cause limitation of knee flexion.

Corkscrew Phenomenon Often an unwary surgeon tends to rotate the second nail by more than 180 , while having difficulty in reducing the fracture and this may lead to one nail being wound around the other, a process termed “corkscrew phenomenon” (Fig. 26). It is more easily possible when the nail size is below the recommended diameter. This phenomenon caused neutralization of the internal tension in the two nails and results in a simple central nail which is neither axially and rotationally unstable. When this is identified in fluoroscopy, the second nail has to be removed and replaced by a rightly placed one.

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Fig. 24 Postoperative radiographs of forearm (a) and C-arm picture of supracondylar region (b) showing nails that are too long outside the bone and are bent away from the bone

Fig. 25 Picture of the knee showing titanium elastic nail penetrating through the skin

Fracture-Specific Errors Failures in Femoral Nailing Perforation of the nail proximally: When the nail is advanced too much, the medial or lateral nail can perforate the cortex (Fig. 27). The nail has to be retracted and then directed ventrally. Subperiosteal positioning of the nail: One or both of the nails, in a long spiral fracture, could come to lie subperiosteally instead of inside the medullary canal.

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Fig. 26 (a) C-arm image and (b) Postoperative radiographs showing corkscrewing of elastic nails during fixation of the tibia

Often this is missed because the stability is initially good due to the subperiosteal position of the nail. Fluoroscopy helps, and the nail is repositioned again.

Failures of Forearm Nailing • Inadequate tensioning of the two nails leads to lack of adequate tensioning of the interosseous membrane. • Radial shaft fractures in the distal thirds and metaphyseal regions are not ideal indications for TEN fixations. In this scenario, the nail must be prebent considerably near the end. • Anterograde nailing of the radius is usually avoided due to risk of injury to the deep branch of the radial nerve. Failures of Humeral Nailing • High lateral entry points in the distal humerus can damage the radial nerve. • Medial insertion point should be avoided to prevent injury to the ulnar nerve. Failures of Tibia Nailing • The tibia bone lies completely eccentric in the musculature and has a triangular cross-section, with a dorsal base and diagonal sides. Hence, symmetrical nails inserted in the coronal plane will result in recurvatum deformity in the tibia (Fig. 28). The correct method would be to have the planes of the nails aligned diagonally, with tension being directed in a dorsal direction.

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Fig. 27 Postoperative radiograph of the proximal femur showing proximal penetration of nail in femur

• Non-union and pseudarthrosis are common in tibia. Distraction at the fracture site should be avoided. • Retrograde tibial nailing for proximal fractures should be avoided as the nail entry (distal) can damage tendons and the strong pull of the patellar ligament cannot be countered by elastic nails.

Complications Complications following elastic nailing can be broadly categorized into major and minor. Major complications include all those which require surgical intervention and/or have long-term morbidity: (1) major angulation (>10 in sagittal/coronal planes, >10 malalignment), (2) major limb length discrepancy (>2 cms lengthening/shortening), (3) deep-seated infections, (4) loss of reduction necessitating further intervention/surgery, (5) compartment syndrome, (6) neurological damage and (7) non-union. Minor complications are those which do not require any surgical intervention or lead to any long-term morbidity: (1) pain at the nail insertion site, (2) minor angulation (150 >110,000 90–100 >1 Normal range >35  C >350 AIS I or II O II A AIS I or II

Borderline 80–100 2–8 Approx 2.5 No data II–III 50–150 90,000–110,000 70–80 Approx 1 Abnormal 33–35  C 300 AIS  2 I–II III B or C AIS II–III

Unstable 60–90 5–15 >2.5 No data III–IV 90 ) at the base of the distal phalanx (this is approximately 1 cm distal to K2) and another bend on each end of the pin. Thus, the skeletal traction is applied when it is engaged in the horns of the first wire. The main advantage of this device is that it provides stability and distraction and, at the same time, allows early motion [47, 48] (Fig. 11).

Intra-articular Fracture of the Distal Interphalangeal Joint The condylar fractures of the middle phalanx are very unstable and should be treated operatively. The treatment is similar to proximal phalangeal fractures, as we described previously, with K-wires or lag screws and trying to perform percutaneously. Nevertheless, the bicondylar fractures of the middle phalangeal with or without severe comminution are really a challenge where we recommended using K-wires configuration or external fixation [47] (Fig. 12). Moreover, in the avulsion fracture of the extensor insertion site, an operative treatment is suggested when the articular component is more than 30% of the articular surface or it is compromised with volar subluxation. Most surgeons prefer the Ishiguro technique, which is performed under fluoroscopy and the distal interphalangeal joint is flexed, then a first K-wire is placed through the

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Fig. 11 (a) Postoperative images of base of the middle phalangeal with severe comminution where is underwent a dynamic external fixation described by Alejandro Badia. (b) This fracture was operated after 3 weeks of the trauma for that reason, it was necessary open reduction and in the red circle shows bending of the end of the first K-wire and this frame configuration causes skeletal traction. (Courtesy by Dr. Dalyn Chavez from Almenara Hospital)

extensor tendon with 45 inclination into the middle phalanx. This K-wire is used as a lever that pushes on the bony fragment once the distal interphalangeal joint is extended, finally the second K-wire is put across the joint to block flexion [49] (Fig. 13).

Conclusion The phalanx fractures are common lesions and a cause of frequent attendance to the emergency department. For that reason, it is crucial that all surgeons choose the adequate treatment between non-operative and surgical management. This choice depends on many factors such as incomplete or complete fracture, displacement, site, comminution, and type of the fracture, open or closed injury. In relation to surgical treatment, the implantology in this type of fracture has had a significant influence over better outcomes and that means a more stable reduction and fixation to allow passive and active motion during the bone healing time. Implant devices are constantly evolving, and can be divided into three categories: (1) Kirschner wires (as temporary or definitive treatment, bearing a list of both advantages and disadvantages), (2) plates and screws (including lag screws, locking plates, and external fixation), and (3) minimally invasive/fracture-specific plates (including low profile, variable angle locking plates and the use of headless screws). All of these remain valid nowadays and carry different pros and cons.

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Fig. 12 (a) AP and lateral radiographs of bicondylar fracture of the middle phalangeal with severe comminution and soft tissue injury. (b) This patient underwent K-wire fixation and block of the distal interphalangeal joint and full thickness skin graft on the wound defect. (c) Postoperative control at 4 weeks which shows healing of the condylar fracture and total integration of the skin graft. In addition, we use a splint protector during these 4 weeks (red circle)

Nevertheless, the choice of implants depends on the pattern and site of fracture, the comminution, the involvement of surrounding soft tissue and surgeon skill. Finally, the hand surgeon may use one or a combination of more implants to obtain an adequate stability and early mobilization.

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Fig. 13 (a) AP and lateral radiographs of avulsion fracture of extensor tendon with articular component more than 30% of the surface with volar subluxation (bony mallet finger). (b) This patient was underwent Ishiguro technique assisted with fluoroscopy

References 1. Karl JW, Olson PR, Rosenwasser MP. The epidemiology of upper extremity fractures in the United States. J Orthop Trauma. 2015;29(8):e242. 2. Minhas SV, Catalano LW III. Comparison of open and closed hand fractures and the effect of urgent operative intervention. J Hand Surg Am. 2018;44:65.e1. 3. Anakwe RE, Aitken SA, Cowie JG, Middleton SD, Court-Brown CM. The epidemiology of fractures of the hand and the influence of social deprivation. J Hand Surg Eur Vol. 2011;36(1): 62–5. 4. Laugharne E, Bhavsar D, Rajaratnam V. The distribution of hand fractures: a British perspective. Eur J Plast Surg. 2013;36:367–70. 5. Watson-Jones R, Wilson JN. Fractures and joint injuries. 6th ed. Edinburgh/New York: Churchill Livingstone; 1982. 6. Carpenter S, Rohde RS. Treatment of phalangeal fractures. Hand Clin. 2013;29:519–34. 7. Graebe A, Tsenter M, Kabo JM, Meals RA. Biomechanical effect of a new point configuration and a modified crosssectional configuration in Kirschner-wire fixation. Clin Orthop. 1992;283: 292–5. 8. Karmani S, Lam F. The design and function of surgical drills and K-wires. Curr Orthop. 2004;18:484–90. 9. Wang D, Sun K, Jiang W. Mini-plate versus Kirschner wire internal fixation for treatment of metacarpal and phalangeal fractures. J Int Med Res. 2020;48(3):1–13. 10. Stahl S, Schwartz O. Complications of K-wire fixation of fractures and dislocations in the hand and wrist. Arch Orthop Trauma Surg. 2001;121:527–30. 11. Heim U, Pfeiffer KM. Internal fixation of small fractures. Technique recommended by the AO-ASIF Group. 3rd ed. Tokyo: Springer; 1988. p. 5–63. 12. Page SM, Stern PJ. Complications and range of motion following plate fixation of metacarpal and phalangeal fractures. J Hand Surg. 1998;23:827–32. 13. Berman KS, Rothkopf DM, Shufflebarger JV, Silverman R. Internal fixation of phalangeal fractures using titanium miniplates. Ann Plast Surg. 1999;42:408–10. 14. Richards RG. The relevance of implant surfaces in hand fracture fixation. In: Herren DB, Nagy L, Campbell DA, editors. Osteosynthesis in the hand: current concepts. FESSH Instructional Course 2008. Basel: Karger; 2008. p. 20–30.

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15. Metsemakers WJ, Schmid T, Zeiter S, Ernst M, Keller I, Cosmelli N, Daniel Arens T, Fintan Moriarty R, Richards G. Titanium and steel fracture fixation plates with different surface topographies: influence on infection rate in a rabbit fracture model. Injury. 2016;47:633–9. 16. Ruchelsman DE, Mudgal CS, Jupiter JB. The role of locking technology in the hand. Hand Clin. 2010;26:307–19. 17. Mudgal CS, Jupiter JB. Plate and screw design in fractures of the hand and wrist. Clin Orthop Relat Res. 2006;445:68–80. Lippincott Williams & Wilkins 18. Lenz M, Wahl D, Gueorguiev B, Jupiter JB, Perren SM. Concept of variable angle locking–evolution and mechanical evaluation of a recent technology. J Orthop Res. 2015;33:988. 19. Baumgart FW, Cordey J, Morikawa K, Perren SM, Rahn BA, Schavan R, Snyder S. AO/ASIF Self-tapping screws (STS). Injury. 1993;24(Suppl 1):S1. 20. Herbert TJ, Fisher WE, Leicester AW. The Herbert bone screw: a ten year perspective. J Hand Surg Am. 1992;17B(4):415. 21. Liodaki E, Kisch T, Wenzel E, Mailander P, Stang F. Percutaneous cannulated compression screw osteosynthesis in phalanx fractures: the surgical technique, the indications, and the results. Eplasty. 2017;17:e8. 22. del Piñal F, Moraleda E, Rúas JS, de Piero GH, Cerezal L. Minimally invasive fixation of fractures of the phalanges and metacarpals with intramedullary cannulated headless compression screws. J Hand Surg Am. 2015;40:692. 23. Aita MA, Mos PAC, Leite G d PCM, Alves RS, Credídio MV, da Costa EF. Minimally invasive surgical treatment for unstable fractures of the proximal phalanx: intramedullary screw. Rev Bras Ortop. 2016;51(1):16–23. 24. Lambotte A. L’intervention ope’ratoire dans les fractures recentes et anciennes. Bruxelles: Lamertin; 1907. 25. De Kesel R, Burny F, Schuind F. Mini external fixation for hand fractures and dislocations: the current state of the art. Hand Clin. 2006;22:307–15. 26. Fitoussi F, Ip WY, Chow SP. External fixation for comminuted phalangeal fractures: a biomechanical cadaver study. J Hand Surg (Br). 1996;21(6):760–4. 27. Walter FL, Papandrea RF. A mini external fixator for hand and finger fractures constructed from readily available materials. Tech Hand Up Extrem Surg. 2011;15(4):215. 28. Suzuki Y, Matsunaga T, Sato S, Yokoi T. The pins and rubbers traction system for treatment of comminuted intraarticular fractures and fracture-dislocations in the hand. J Hand Surg (Br Eur Vol). 1994;19B:98–107. 29. Badia A, Riano F, Ravikoff J, Khouri R, Gonzalez-Hernandez E, Orbay JL. Dynamic intradigital external fixation for proximal interphalangeal joint fracture dislocations. J Hand Surg Am. 2005;30A(1):154. 30. Eberlin KR, Babushkina A, Neira JR, et al. Outcomes of closed reduction and periarticular pinning of base and shaft fractures of the proximal phalanx. J Hand Surg Am. 2014;39(8):1524–8. 31. Faruqui S, Stern PJ, Kiefhaber TR. Percutaneous pinning of fractures in the proximal third of the proximal phalanx: complications and outcomes. J Hand Surg Am. 2012;37(7):1342–8. 32. Faruqui S, Stern PJ, Kiefhaber TR. Percutaneous pinning of fractures in the proximal third of the proximal phalanx: complications and outcomes. J Hand Surg. 2012;37A:1342. 33. Al-Qattan MM. Displaced unstable transverse fractures of the shaft of the proximal phalanx of the fingers in industrial workers: reduction and K-wire fixation leaving the metacarpophalangeal and proximal interphalangeal joints free. J Hand Surg Eur Vol. 2011;36(7):577–83. 34. Day CS, Stern PJ. Fractures of the metacarpals and the phalanges. In: Wolfe S, Pederson W, Hotchkiss R, Kozin S, editors. Green’s operative hand surgery, vol. 1. Philadelphia: Elsevier/ Churchill Livingstone; 2011. p. 239–90. 35. Gaston RG, Chadderdon C. Phalangeal fractures: displaced/nondisplaced. Hand Clin. 2012;28(3):395–401. 36. Giesen T, Gazzola R, Poggetti A, Giovanoli P, Calcagni M. Intramedullary headless screw fixation for fractures of the proximal and middle phalanges in the digits of the hand: a review of 31 consecutive fractures. J Hand Surg (Eur Vol). 2016;41(7):688–94.

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37. Henry MH. Fractures of the proximal phalanx and metacarpals in the hand: preferred methods of stabilization. J Am Acad Orthop Surg. 2008;16:586–95. 38. Black DM, Mann RJ, Constine RM, et al. The stability of internal fixation in the proximal phalanx. J Hand Surg Am. 1986;11:672–7. 39. Firoozbakhsh KK, Moneim MS, Howey T, et al. Comparative fatigue strengths and stabilities of metacarpal internal fixation techniques. J Hand Surg. 1993;18:1059–68. 40. Verver D, Timmermans L, Klaassen RA, van der Vlies CH, Vos DI, Schep NWL. Treatment of extra-articular proximal and middle phalangeal fractures of the hand: a systematic review. Strat Trauma Limb Reconstr. 2017;12:63–76. 41. Prevel CD, Eppley BL, Jackson JR, et al. Mini and micro plating of phalangeal and metacarpal fractures: a biomechanical study. J Hand Surg. 1995;20:44–9. 42. Adams JE, Miller T, Rizzo M. The biomechanics of fixation techniques for hand fractures. Hand Clin. 2013;29:493–500. 43. Lögters TT, Lee HH, Gehrmann S, Windolf J, Kaufmann RA. Proximal phalanx fracture management. Hand. 2018;13(4):376–83. 44. Robinson LP, Gaspar MP, Strohl AB, et al. Dorsal versus lateral plate fixation of finger proximal phalangeal fractures: a retrospective study. Arch Orthop Trauma Surg. 2017;137(4):567–72. 45. Onishi T, Omokawa S, Shimizu T, et al. Predictors of postoperative finger stiffness in unstable proximal phalangeal fractures. Plast Reconstr Surg. 2015;3(6):e431. 46. Shewring DJ, Miller AC, Ghandour A. Condylar fractures of the proximal and middle phalanges. J Hand Surg Eur Vol. 2015;40E(1):51–8. 47. Oak N, Lawton JN. Intra-articular fractures of the hand. Hand Clin. 2013;29:535–49. 48. Mansha M, Miranda S. Early results of a simple distraction dynamic external fixator in management of comminuted intra-articular fractures of base of middle phalanx. J Hand Microsurg. 2013;5(2):63–7. 49. Botero SS, Diaz JJH, Benaïda A, Collon S, Facca S, Liverneaux PA. Review of acute traumatic closed mallet finger injuries in adults. Kor Soc Plastic Reconstr Surg. 2016;43(2):134.

Upper Limb Orthopaedic Trauma Implantology in a Nutshell

77

Ravi Ganesh Bharadwaj

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Current Concepts in Upper Limb Implantology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

The past few decades have witnessed growing urbanisation leading to an increase in high energy injuries resulting in complex fracture patterns, especially of the upper limb. Improvements in our understanding of the biomechanics of these injuries, coupled with technological advancements in imaging, metallurgy, computeraided design and 3D printing, have led to development of a variety of specific implants to enable fixation of difficult fractures. It is up to the operating surgeon to understand the fracture personality as well as biomechanical principles of the available implants and make a judicious choice based on these considerations. Keywords

Ideal implant · Upper limb fractures

Introduction The past few decades have witnessed growing urbanisation leading to an increase in high energy injuries resulting in complex fracture patterns. R. G. Bharadwaj (*) Apollo Multispecialty Hospitals, Kolkata, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_77

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Improvements in our understanding of the biomechanics of these injuries, coupled with technological advancements in imaging, metallurgy, computer-aided design and 3D printing, have led to development of a variety of specific implants to enable fixation of difficult fractures. An ideal implant should have a modulus of elasticity similar to cortical bone, be biologically inert, be sufficiently low profile, respect biology by allowing for stable fixation without much soft tissue disruption or stripping, be versatile enough to tackle various fracture patterns and also enable easy removal, should it be necessary.

Current Concepts in Upper Limb Implantology The individual upper limb fractures, along with the available implants to treat them, have already been discussed in the preceding chapters. This chapter is a summary of the current consensus regarding upper limb implants. Clavicular fractures were traditionally treated conservatively. With time, it became evident that significantly displaced fractures and fractures of the lateral end of the clavicle did not do well with non-operative treatment. A variety of intra-medullary and extra-medullary devices have been used to fix fractures of the clavicle [1]. Intramedullary nailing of the clavicle is indicated in mid-shaft bending or fragmented-wedge clavicle fractures in young and active patients and offer the advantage of being minimally invasive as well as allowing early mobilization. The implants that have found most favour are the present generation of anatomical locking plates with different implants that allow either superior or anterior placement over the shaft, or over the lateral end of the clavicle. Stable fixation of even small distal fragments of the lateral end of the clavicle are possible with the use of these plates. Tightropes with endo-button fixation are being used to treat ligamentous injuries of the acromio-clavicular joint. Proximal humerus fractures have long posed to be a challenge, especially in the elderly. Numerous classification systems have been developed to classify, prognosticate and offer treatment guidelines for these fractures. Factors determining the preferred treatment depend on the fracture pattern, bone quality, patient’s age and general health, handedness, functional demand and any other associated injuries. While many proximal humerus fractures can be treated conservatively, displaced two-, three- or four-part fractures, head split fractures, fracture dislocations, open fractures and fractures in the setting of associated neurovascular or other skeletal injuries are treated operatively. Primary arthroplasty options (hemi, total or reverse shoulder arthroplasty) are considered when dealing with unreconstructible fractures, head split fractures or fracture dislocations, especially those with delayed presentation, fractures in the elderly with associated rotator cuff and glenoid pathology [2]. Internal fixation with plates is preferred in most other cases. Proximal humerus locking plates and the peri-articular locking plates have proved to be very useful in this situation. These implants are designed to accommodate a

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number of multi-directional locking screws in the head. This offers a combination of angular and rotational stability, which is a particularly useful feature for fracture fixation in elderly patients with osteoporotic bone [3]. Proper repositioning of the tuberosities is essential and many plate systems offer suture-holes through which non-absorbable sutures can be passed to augment the fixation of the tuberosities. Use of a calcar screw to support the medial calcar offers additional stability against varus collapse [4]. Despite this, screw cut-out and loss of fixation is common due to poor bone quality, increased implant stiffness and stresses at the implant-bone-interface. Augmentation with bone cement, intra-medullary fibular bone graft [5] and addition of a small plate anteriorly [6] (orthogonal double plate fixation) are different strategies that have been used to deal with this particular problem. Proximal humeral intra-medullary nails with multiple locking options are also gaining popularity in treatment of these fractures [7]. Contemporary nails feature a straight design, with a more central entry point. Although many shaft humerus fractures can be treated conservatively, some of them are treated operatively to allow anatomical reduction and early mobilization, or where open reduction is a requirement to explore the radial nerve for a concomitant radial nerve palsy. Several designs of locking plates as well as intra-medullary nails are now available for the treatment of these fractures [8]. Implants like the distal humerus extra-articular locking plate offer the advantages of anatomical reduction and stable fixation in distal third humeral shaft as well as supracondylar fractures in adults. Intra-articular fractures of the distal humerus are treated by internal fixation. Depending on the fracture pattern, exposure may sometimes require an olecranon osteotomy to visualize the fracture fragments and facilitate the reduction and fixation. Although a variety of implants have been used to fix the lateral and medial columns of the distal humerus, the use of anatomically contoured locking distal humerus plates has gained popularity in recent times [9]. The current generation of anatomical locking plates offers a variable angle feature to allow accurate screw placement, thus avoiding the passage of screws into the fracture site. The distal humerus plates can be applied either in a parallel or a perpendicular configuration. The fundamental principle is to reconstruct the articular surface accurately and to enable secure fixation of the articular block to the lateral and medial columns, extending to the shaft of distal humerus. If an olecranon osteotomy is used, it is usually fixed employing a tension band wiring technique using stainless-steel wire loop and K-wires or an intramedullary screw. Alternatively, an anatomically contoured olecranon locking plate can be used. Isolated shear fractures of the capitellum and the trochlea (without comminution of the posterior cortex) are usually fixed using headless compression screws [10]. Involvement of the posterior cortex may necessitate the addition of a buttress plate. Radial head fractures usually require a computed tomography (CT) scan for better understanding of the fracture geometry. It is possible to fix two- or three-part fractures with mini screws or a radial head T-plate. Comminuted fractures of the radial head with more than three fragments are usually treated by a radial head prosthetic replacement [11]. It is important to size the prosthesis correctly, to avoid

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overstuffing the joint. Concomitant ligamentous injuries (in the setting of a terrible triad of the elbow) are often repaired with suture anchors. A large coronoid process fracture may compromise the elbow stability and these fractures can be approached through a separate medial approach and fixed with a coronoid buttress plate or a suture lasso [12]. Transverse olecranon fractures are usually treated by tension band wiring while more complex, comminuted olecranon fractures are usually fixed with an anatomically contoured olecranon locking plate. Fractures of the shaft of the radius and ulna are treated on the principles of intraarticular fractures and require anatomical reduction with accurate restoration of the radial bow. This is usually achieved by plate fixation. The use of dynamic compression plates allows compression at the fracture site. Locking plates are useful in osteoporotic bone. Most plates offer the option of using both locking and cortex screws [13]. Fractures of the distal ulna can pose a challenge because of the subcutaneous location and thin bone diameter. The availability of specific low profile distal ulna locking plates has made fixation of the small distal fracture fragments easier. There has been an improved understanding of wrist biomechanics in the past three decades. The three-column concept and the fragment specific classification as well as the four-corner concept have led to the development special low-profile plates for fragment specific fixation [14]. The current generation of volar locking plates allows stable fixation of most distal radius fractures. In some instances, fragment-specific dorsal plates, radial styloid plates or hook plates for the volar lunate fossa fragment may be required. Very distal fractures may require the use of rim plates which extend beyond the watershed line. These are usually removed after fracture union. Wrist spanning distraction plates can be used for extremely comminuted distal radius fractures that are not amenable to primary stable fixation. These plates are applied via a dorsal approach, and function as an internal “external fixator”. These are removed usually around 3 months and further definitive surgery carried out if and as necessary. Increasing use of CT and MRI scans as well as wrist arthroscopy have contributed greatly to our understanding of wrist pathologies. The scaphoid is the most commonly fractured carpal bone. Displaced fractures of the scaphoid are usually treated by headless compression screw fixation, either through an open, percutaneous or arthroscopy assisted technique. Scaphoid plates are also available for comminuted scaphoid fractures presenting with a hump-back deformity. The use of suture anchors has greatly facilitated the management of ligamentous injuries of the wrist. Other carpal fractures like the trapezium, capitate, hamate, etc. can be treated either by small headless screws or mini screws. Unstable metacarpal and phalangeal fractures can be fixed with low profile mini plates and screws. These allow anatomical reduction are early mobilization, thus avoiding stiffness. The current generation of plates offer a variable angle locking option also. Articular fractures can be fixed using mini-screws. The use of intramedullary headless compression screws for transverse metacarpal and proximal phalanx fractures is also gaining popularity [15], [16]. Avulsion fractures can be treated using suture anchors. Sometimes, K-wires and external fixation are also useful.

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Conclusion When confronted by the wide array of available implants for each fracture, it is expected that the treating surgeon should be aware of the treatment principles, fracture biomechanics, fracture personality as well as the implant characteristics of the chosen implant and make a judicious choice based on these considerations.

References 1. Clinical practice guidelines (CPG) for the treatment of clavicle fractures, American Academy of Orthopaedic Surgeons (AAOS), January 2023. 2. Chalmers PN, Slikker W, Mall NA, Gupta AK, Rahman Z, Enriquez D, Nicholson GP. Reverse total shoulder arthroplasty for acute proximal humeral fracture: comparison to open reductioninternal fixation and hemiarthroplasty. J Shoulder Elb Surg. 2014;23:197–204. 3. Voigt C, Geisler A, Hepp P, Schulz AP, Lill H. Are polyaxially locked screws advantageous in the plate osteosynthesis of proximal humeral fractures in the elderly? A prospective randomized clinical observational study. J Orthop Trauma. 2011;25:596–602. 4. Gardner MJ, Weil Y, Barker JU, Kelly BT, Helfet DL, Lorich DG. The importance of medial support in locked plating of proximal humerus fractures. J Orthop Trauma. 2007;21:185–91. 5. Chow RM, Begum F, Beaupre LA, Carey JP, Adeeb S, Bouliane MJ. Proximal humeral fracture fixation: locking plate construct  intramedullary fibular allograft. J Shoulder Elb Surg. 2012;21:894–901. 6. Hessmann MH, Korner J, Hofmann A, Sternstein W, Rommens PM. Angle-fixed plate fixation or double-plate osteosynthesis in fractures of the proximal humerus: a biomechanical study. Biomed Tech (Berl). 2008;53:130–7. 7. Dilisio MF, Nowinski RJ, Hatzidakis AM, Fehringer EV. Intramedullary nailing of the proximal humerus: evolution, technique, and results. J Shoulder Elb Surg. 2016;25:e130–8. 8. Zhao JG, Wang J, Meng XH, Zeng XT, Kan SL. Surgical interventions to treat humerus shaft fractures: a network meta-analysis of randomized controlled trials. PLoS One. 2017 Mar;12(3): e0173634. 9. Haglin JM, Kugelman DN, Egol KA, et al. Intra-articular distal humerus fractures: parallel versus orthogonal plating. HSS J. 2021 Apr;18(2) https://doi.org/10.1177/15563316211009810. 10. Watson JJ, Bellringer S, Phadnis J. Coronal shear fractures of the distal humerus: current concepts and surgical techniques. Shoulder Elbow. 2020 Apr;12(2):124–35. 11. Swensen SJ, Tyagi V, Uquillas C, Shakked RJ, Yoon RS, Liporace FA. Maximizing outcomes in the treatment of radial head fractures. J Orthop Traumatol. 2019 Mar 23;20(1):15. 12. Lor KKH, Toon DH, Wee ATH. Buttress plate fixation of coronoid process fractures via a medial approach. Chin J Traumatol. 2019 Oct;22(5):255–60. 13. Leung F, Chow SP. Locking compression plate in the treatment of forearm fractures: a prospective study. J Orthop Surg. 2006;14(3):291–4. 14. Slutsky DJ, Osterman AL. Fractures and injuries of the distal radius and carpus-the cutting edge. Philadelphia: Saunders/Elsevier; 2009. 15. Dyrna FGE, Avery DM, et al. Metacarpal shaft fixation: a biomechanical comparison of dorsal plating, lag screws, and headless compression screws. BMC Musculoskeletal Disord. 2021;22:335. 16. Lögters TT, Lee HH, Gehrmann S, Windolf J, Kaufmann RA. Proximal phalanx fracture management. Hand (N Y). 2018 July;13(4):376–83.

Part XIV Lower Limb Orthopaedic Trauma Implantology

Implantology of Fractures of the Head of Femur

78

John Mukhopadhaya and Janki Sharan Bhadani

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History of development of implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Femoral head fractures, also known as Pipkins fractures, are more common in young and are usually caused by high-energy trauma. Controversies in the management of Pipkins fracture still exist between excision, osteosynthesis, and arthroplasty. For internal fixation, multiple implants have been tried including Smillie pins, Kirschner wires, screws including mini- or small-fragment cortical screws (2.0–3.5 mm) with countersinking of the head, headless screws like the Herbert screw, and bioabsorbable pins. Fixation can be challenging and may be best done through a safe surgical dislocation using a trochanteric flip osteotomy or through an anterior modified Smith-Peterson approach. Total hip arthroplasty as well as hemiarthroplasty are also advocated for these fractures in certain situation. Keywords

Femoral head fracture · Pipkins fracture · Hip fracture · Proximal femur fracture · Osteosynthesis · Arthroplasty

J. Mukhopadhaya (*) · J. S. Bhadani (*) Paras HMRI Hospital, Patna, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_78

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J. Mukhopadhaya and J. S. Bhadani

Introduction Femoral head fracture also known as Pipkins fracture is a rare injury. It is usually due to high-energy trauma. It is common in young patients and associated with posterior dislocation of hip joint, fracture of adjacent bone, and injury to other parts of body. Birkett et al. reported the first description of fracture of femoral head in a 35-year-old female after her death following fall from height in 1869 [1]. Controversies about its management still exists between excision, osteosynthesis, and arthroplasty. For internal fixation, multiple implants were described in literature including nonabsorbable stainless steel and biodegradable implants. Epstein et al., believed that close reduction should not be performed if open reduction and fixation is planned [2]. Like any other intra-articular fracture, anatomical reduction and stable fixation is prerequisite to fix these fractures.

History of development of implants Most of Pipkins fractures are treated surgically. Conservative treatment is only acceptable in case of anatomical reduction of fracture fragments of head on postreduction CT [3]. All procedures should therefore focus on the best possible restoration of the joint anatomy [3]. Small articular bone or free small piece of bone, as well as loose bodies beneath the fovea can be safely excised without altering the load across hip joint [3, 4]. Small labral tear should debrided while large labral tear should be fixed with suture anchor [5]. While fixing the large fragments of femoral head with intact inferior retinaculum, the inferior retinaculum should be preserved as these fragments mostly get their blood supply through the retinaculum. Multiple implants have been tried for fixation of osteochondral fractures of weight-bearing joint including femoral head fractures that include Smillie pins, Kirschner wires, screws including mini- or small-fragment cortical screws (2.0–3.5 mm) with countersinking of the head, headless screws like the Herbert screw, and bioabsorbable pins. Herbert screw was designed to overcome the problems associated with fixation of the fractured scaphoid [6, 7], and later used for Pipkins fractures. It has differential threads, that is, a greater pitch thread at leading end than the trailing end for compression of fracture fragment. It is headless to avoid articular cartilage damage and impingement [5]. Fixation may also be done with mini- or small-fragment cortical screws (2.0–2.7 mm) after countersinking head of screw below the cartilage level [9] (Fig. 1). Three-millimetre cannulated screws with threaded washers were also tried, which achieved excellent compression, reportedly higher than many other implants. The 3 mm screws worked very well, and were associated with excellent compression and outstanding radiographic results in the early follow-up. However, there is high chance of screw backout and degenerative arthritis [8].

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Fig. 1 Type II Pipkin fracture with posterior dislocation of hip joint: (a and b) preoperative imaging: X-ray: AP and lateral views; (c and d) CT scan with 3D reconstruction, axial CT cut; (e) intraoperative photographs showing trochanteric flip osteotomy site, reduction, and fixation of head of femur by multiple screws; and (f) postoperative radiograph AP view

Bioabsorbable screw (polyglycolide and polylactide implants) can also be used to fix these fractures without the need of implant removal [9]. Arthroscopic osteosynthesis had also been done by Yamamoto et al., using bioabsorbable screws. However, due to limited joint space in the hip joint, this cannot be done in all types of Pipkins fracture. This technique allows early rehabilitation and is expected to prevent the development of osteoarthritis after hip trauma [10]. Bioabsorbable pins have been reported to achieve inadequate compression in few of the studies. It can also result in delayed inflammatory reaction, sterile sinus, and delayed wound swelling [11]. Femoral head fractures associated with femoral neck fracture are considered as type III Pipkin fracture. Literature is divided regarding management of these types of fractures between arthroplasty and osteosynthesis. Many surgeons favour primary arthroplasty even at a young age due to the risk of avascular necrosis, which is as high as 50% as reported by Giannoudis et al. [12] In young patients, however, it may be worth trying to fix these fractures to delay the need for arthroplasty [13]. Fixation can be challenging and may be best done through a safe surgical dislocation using trochanteric flip osteotomy [14, 15] (Fig. 2). Similarly type IV fracture may be fixed using the posterior Kocher-Langenbeck approach to fix the acetabular fracture and then using the safe surgical dislocation to fix the femoral head. Total hip arthroplasty as well as hemiarthroplasty was also reported for these fractures [15] (Fig. 3).

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Fig. 2 Type III Pipkin fracture: (a and b) preoperative imaging: CT scan with 3D reconstruction, (c) intraoperative photographs after open reduction and fixation of fractured neck, head of femur, and trochanteric flip osteotomy site by multiple locking screws, and (d) postoperative radiographs

Fig. 3 Type IV Pipkin fracture: femoral head and acetabular fracture associated with posterior dislocation of hip joint: (a) preoperative radiograph: AP, (b) CT scan with 3D reconstruction, (c and d) sagittal and axial CT cut, (e) postoperative radiograph AP view showing fixation of head with locking screw, acetabular fracture using Matta plate, and fixation of trochanteric flip osteotomized site using cortical 3.5 mm screws

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Conclusion A fracture of the head of the femur is a separate entity altogether. It is common in the young due to high-energy trauma, unlike the hip fractures in the elderly, which are usually caused by low-energy trauma. Multiple implant options to manage these fractures have been described in the literature. Decision-making and appropriate treatment of these fractures are challenging. Preservation of native hip in the young is of prime importance. However, risk of avascular necrosis (AVN) will always be there which may require subsequent surgery.

References 1. Birkett J. Description of a dislocation of the head of the femur, complicated with its fracture; with remarks. Med Chir Trans. 1869;52:133–8. 2. Epstein HC, Wiss DA. Traumatic anterior dislocation of hip. Orthopaedics. 1985;8:132–4. 3. Henle P, Kloen P, Siebenrock KA. Femoral head injuries: which treatment strategy can be recommended ? Injury. 2007;38(4):478–88. 4. Holmes, et al. Biomechanical consequences of excision of displaced pipkin femoral head fractures. J Orthop Trauma. 2000;14:149–50. 5. Murray P, McGee HM, Mulvihill N. Fixation of femoral head fractures using the Herbert screw. Injury. 1988;19(3):220–1. 6. Herbert TJ, Fisher WE. Management of the fractured scaphoid using a new bone screw. J Bone Joint Surg Br. 1984;66(1):114–23. 7. Murray P, McGee HM, Mulvihill N. Fixation of femoral head fractures using the Herbert screw. Injury. 1988;19(3):220–1. https://doi.org/10.1016/0020-1383(88)90023-x 8. Stannard JP, Harris HW, Volgas DA, Alonso JE. Functional outcome of patients with femoral head fractures associated with hip dislocations. Clin Orthop Relat Res. 2000;377:44–56. 9. Jukkala-Partio K, Partio EK, Hirvensalo E, Rokkanen P. Absorbable fixation of femoral head fractures. A prospective study of six cases. Ann Chir Gynaecol. 1998;87(1):44–8. 10. Yamamoto Y, Ide T, Ono T, Hamada Y. Usefulness of arthroscopic surgery in hip trauma cases. Arthroscopy. 2003;19(3):269–73. 11. Kulkarni RK, Moore EG, Hegyeli AF, Leonard F. Biodegradable poly(lactic acid) polymers. J Biomed Mater Res. 1971;5:169–81. 12. Giannoudis PV, Kontakis G, Christoforakis Z, Akula M, Tosounidis T, Koutras C. Management, complications and clinical results of femoral head fractures. Injury. 2009;40(12):1245–51. 13. Mukhopadhaya J, Bhadani JS, Shyam A. Functional outcome of pipkin type iii fracture managed by osteosynthesis through trochanteric flip osteotomy in a young patient after 5 years follow-up – a case report and literature review. J Orthop Case Rep. 2021;08:101–6. 14. Ganz R, Gill TJ, Gautier E, Ganz K, Krügel N, Berlemann U. Surgical dislocation of the adult hip a technique with full access to the femoral head and acetabulum without the risk of avascular necrosis. J Bone Joint Surg Br. 2001;83(8):1119–24. 15. Yu X, Pang QJ, Chen XJ. Clinical results of femoral head fracture-dislocation treated according to the Pipkin classification. Pak J Med Sci. 2017;33(3):650–3.

Implantology of Fractures of the Neck of Femur

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John Mukhopadhaya and Janki Sharan Bhadani

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History of Development of Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Use of Fixation Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neck of Femur Fracture in Pediatric Age . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arthroplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monopolar Prosthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bipolar Hemiarthroplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Total Hip Arthroplasty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

About two centuries ago Sir Astley Cooper differentiated between the extracapsular and intra-capsular fractures of the neck of femur and noticed poor prognosis in the latter. Intra-capsular fractures are also known as unsolved fracture, as over the years numerous methods of treatment including conservative as well as surgical have been tried, but we are yet to come with an adequate solution. Surgical management includes osteosynthesis and arthroplasty. Multiple implants for fixation including screw(s) in different configurations, different types of nails, combination of nail-plate system, bone graft, etc. still exist, especially in younger age, non-displaced, and reducible fractures. While in other cases arthroplasty continues. Different materials like ivory, wood, silver steel, Vitallium, titanium, etc. were used. Before the development of the idea of using inert material and concept of biocompatibility there was high failure rate. Mixture of plaster of Paris and powdered pumice were also tried before use of PMMA in cemented arthroplasty. There were many landmark contributions in arthroplasty, J. Mukhopadhaya (*) · J. S. Bhadani (*) Paras HMRI Hospital, Patna, India e-mail: jsbhadani@orefindia.com © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_118

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including Judet, Thompson FR, and Austin Moore for monopolar prosthesis, James Ennis Bateman for bipolar prosthesis, and Sir John Charnley and Peter Ring for cemented as well as uncemented total hip arthroplasty, respectively. Keywords

Femoral neck fractures · Hip fracture · Proximal femur fracture · Osteosynthesis · Arthroplasty · Dynamic hip screw · Cannulated screws · Femoral neck system Abbreviation

3D CT AMP AO AP BDSF CCS CT DHS DS FNS MABP P.M.M. A SCAP FN SP Nail THA THR

Three-dimensional computed tomography Austin Moore prosthesis Arbeitsgemeinschaft für osteosynthesefragen Anteroposterior Biplane double-supported screw fixation Cannulated cancellous screws Computed tomography Dynamic hip screw Derotation screw Femoral neck system HA Medial anatomical buttress plate Polymethyl methacrylate Slide compression anatomic place-femoral neck Smith-Peterson Nail Total hip arthroplasty Total hip replacement

Introduction Intra-capsular fractures of the neck of femur is one fracture which has continued to be a challenge for surgeons. Over the years numerous methods of treatment have been tried but problems of non-union, avascular necrosis, failures of fixation, and shortening continue to be significant complications for which we are yet to come with adequate solutions. Speed et al., called these as “the unsolved fracture” due to the high failure rate [1]. The first historically documented case of femoral neck fracture may be from the fourteenth century, when the Roman Emperor Charles IV (1316–1378) was thought to have died following a fracture neck femur [2]. The first clinical report of this fracture is by Ambroise Paré (1510–1590) in his “Works of Ambroise Pare”. He was the personal doctor of four French kings [1]. He also described a method of reducing the fracture and holding it together in a brace. Heister (1683–1758) and Ruysh (1638–1731) subsequently described the pathology based on autopsy findings [3]. In the following years, multiple methods were devised by different surgeons to reduce and splint these fractures. Mainly three types of conservative treatment have been historically described: hip spica, traction, and a

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combination of both. Traction is the oldest method of treating proximal femoral fractures. Royal Whitman (1898) introduced abduction treatment for fractures of the hip with the aid of a plaster spica [4].

History of Development of Implants Sir Astley Cooper (1768–1841) was the first to recognize the difference between the extra-capsular fractures and intra-capsular fractures of the neck of femur. He was also the first to recognize the difference in prognosis between the two fracture types [5]. Albin Lambotte (1866–1955) coined the term osteosynthesis [6]. Robert Smith described the basis of healing of fracture by aligning the fragments. Thus, he reported that impacted intra-capsular fractures were more likely to heal [7].

Use of Fixation Devices Surgical fixation for a non-union of fracture neck of femur was probably first performed by von Langenbeck in around 1850 using a fine gimlet percutaneously. However, the patient had an infection and died [8]. Later Franz König (1875) was able to successfully achieve healing of the fracture in a young patient using percutaneous insertion of the gimlet with aseptic precautions [2]. At the beginning of the twentieth century the method of surgical treatment for proximal femur fractures was improved by European surgeons Lambotte, Delbet, and Putti [8]. In cadaveric studies, Friedrich Trendelenburg tried using ivory pegs, ivory screws, and silver screws for intra-capsular fractures [8]. In 1891, Dollinger probably was the first who successfully did open reduction of an extra-capsular fracture of the femoral neck and fixation using sutures of silver wire [8]. Julius Nicolaysen (1897) reported on 13 cases of fracture neck of femur treated with a steel spike. The spike was used to fix the fracture after reduction with traction and the head of the spike was left outside the skin and incorporated into a spica cast which was maintained for 8–10 weeks. He operated on these patients without anesthesia [3]. Healing of non-union of these fractures was reported by stepwise resection of the scarred fibrous tissue followed by fixation using silver wire by Russian surgeons, Derjushinski and Michalkin [8]. External fixation was advised for intra-capsular fractures by Clayton Parkhill (1898). Internal fixation using bone and ivory peg were used by Arthur J. Gillette (1898) for inveterate fractures of the femoral neck after greater trochanter resection [8]. Albin Lambotte (1906) successfully managed transtrochanteric fractures and basicervical-type femoral neck fractures by open reduction and internal fixation using two screws [8]. Screws with threads were first used by Pierre Delbet in 1907. These screws were available in different lengths and were partially wormed (threaded), so they actually helped to compress the fracture [3]. He also used a targeting device called the Delbet cannon which was the first targeting device recorded in the literature [8]. Albee in 1912 used an autogenous bone peg as a fixation device. He used a tibial graft. Pierre Delbet was probably the first to use a

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free fibular graft as a fixation device while Ellis Johnson reported on a trochanteric transplantation graft as a fixation device [3]. In 1914, Preston from New York designed the first prototype of a 110 -angled blade plate for internal fixation of fractures of the femoral neck; however, he did not use it [8]. In 1923, Martin and King [8] from New Orleans published their method of internal fixation of fractures of the femoral neck by using two wood screws to eliminate long-term postoperative immobilization. They stated, “two screws properly inserted will hold far better than one”. Carpentry screws were used by Ernest William Hey Groves (1926) [9]. Smith-Peterson in 1925 introduced the tri-flanged nail for fixation of these fractures which ushered in a new era in the fixation of fractures of the neck of femur. Along with Cave and Vangorder, he described the technique of open reduction and internal fixation of these fractures. He also emphasized the importance of anatomical reduction and reported on their results in 1931 [3]. Sven Johansson further refined this into cannulated nail to insert the nail over a guide wire under radiological control. Thus, closed reduction with internal fixation with minimally invasive techniques became possible [10].Thornton (1937) first came with the idea of a metallic plate combined with Smith-Petersen nail and McLaughlin devised a plate combined with the SmithPeterson nail where the nail could be at different angles from the plate (so-called multiple-angle device) [9, 11]. Bousquet. E.L. Jewett (1941) manufactured a threewinged fixed angle nail-plate system [12]. However, there was high incidence of cut through and implant failure as it did not allow collapse. To counteract the shortcoming of this device, Pugh (1955) developed a telescoping nail-plate system using 135 degrees fixed angle plate to allow impaction [13]. Charnley (1956) devised a compression screw-plate system to maintain compression between fracture fragment with “springloading” allowing for bone resorption [14]. However, it also had tendency to cut out of the femoral head [15]. Together with the Pugh nail plate, this device was taken into consideration for the development of Richards compression screw system which was used more commonly for trochanteric fracture [16]. AO introduced angled blade plate, a fixed angle implant in 1960s which needs surgical expertise and 3D orientation of proximal femur (Fig. 1). It is used for fracture treatment including unstable fracture neck of femur, revision surgery, and correction osteotomies and serve as a tension band plate [17]. Crossed screw fixation was advocated by Garden using two crossed screws for the fixation of fracture neck femur in which screws were ideally crossed in both planes. Smyth combined two crossed screws with a plate in triangular fashion. In this method he followed the trabecular columns which supports the femoral neck [18]. In both of these techniques, the first screw was to be inserted almost transversely through the anterior part of trochanter into inferior part of femoral head. The second screw to be inserted below the first one in oblique fashion by either using a guide (Garden) or through triangular connecting plate (Smyth). This was followed by the advent of cannulated cancellous screws in which parallel screws were used to allow for compression of the fracture during fixation and also allow for healing of these fractures. Most common implants for osteosynthesis of fracture neck of femur currently used are multiple cannulated screws or dynamic hip screw (DHS)+ derotation screw

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Fig. 1 Radiographs showing AO angled blade plate in AP (anteroposterior) and lateral view

(DS) with a side plate. In case of undisplaced intra-capsular hip fracture or when stable acceptable reduction was achieved in displaced fracture, currently close reduction cannulated screw system or sliding screw device with a short plate with or without derotation screw are considered as option. Number of cannulated screws, their optimal position (parallel or divergent), and using it with or without washer are still debatable. Number of CCS: Krastman et al. suggested two percutaneous cannulated hip screws for Garden I/II fractures, or for anatomically reduced Garden type III/IV fractures, irrespective of the Pauwels classification [19]. Most surgeons who use a cannulated screw system prefer to use three screws in parallel inverted triangle configuration such a way that these are in an inferior, central, and superior position on the AP view and superimposing each other in the central portion of the head on the lateral view. Four screws in diamond configuration can also be used [20] (Fig. 2). Orientation of screws: When a lag screw inserted from the greater trochanter towards inferior neck with other 2–3 cancellous screws in parallel after reduction of intra-capsular fracture, this is known as Pauwel screw configuration. This construct would perform better than parallel screws configuration [21].. Pauwels configuration showed 70% more stiffness when compared with parallel screws in a biomechanical study [22]. Godoy Moreira (1938) invented sliding compression with cannulated system of drilling to minimize implant failure for fracture neck of femur. William Massie introduced a sliding hip nail. He also explained that non-anatomic fixation in valgus with high-angle telescoping nail decreases the risk of non-union but not osteonecrosis [23]. Multiple modifications of this device were done time to time, including a blunt-tipped cannulated screw design coupled to a forged side plate, multiple neck angles, and keyed slot for more rotational stability [20]. Biomechanical studies suggest that although a sliding hip screw provides greater resistance to shearing force, multiple cannulated cancellous screws (CCS) provide greater resistance to rotational forces. Shearing and rotational forces are first and second most common causes of implant failure, respectively. More recently to deal with

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Fig. 2 (a) CCS with guide wire, (b) dynamic hip screw. Radiographs showing modes of fixation of femoral neck fractures: (c, d) AP and lateral views: using three CCS in inverted triangle pattern, (e, f) AP and lateral views: using four CCS in diamond configuration, (g) AP view: using DHS+ derotation screw

shortcoming of these implants system, like excessive collapse seen with use of cannulated cancellous screw, multiple newer implants were developed with limited success. (A) Biplane double-supported screw fixation (BDSF) method in femoral neck fractures developed by O. Filipov is based on the concept of the establishing two supporting points for the implants and their biplane positioning at obtuse angle in the femoral neck and head (Fig. 3). This method is original with the three screws being laid in two planes. In this method the entry points of two screws are much more distal in the solid cortical bone of proximal diaphysis. These screws should also lean onto the strong femoral neck distal cortex to establish two points of support. The position of the distal screw and the middle screw turns them into a simple beam with an overhanging end, loaded by a vertical force. This configuration successfully supports the head fragment, bearing the body weight and transferring it to the diaphysis. The position of the screws allows them to slide under stress at minimum risk of displacement. This method allows early rehabilitation and better long-term outcomes than conventional method of screw fixation, even in non-cooperative patients [24]. (B) Targon FN system is made of titanium alloy and designed for minimally invasive surgery for the neck of femur fracture. It consists of a small locking side plate, with two distal locking shaft screw options and four proximal locking telescoping screw options that allow for up to 20 mm of sliding compression. Linking all these screws with the side plate gives a much more stable construct with rotational and angular stability. Initially, there were some difficulties in using this in Japanese women with the smaller femoral neck. So, an additional guide was

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Fig. 3 Radiographs showing fixation of femoral neck fractures using the biplane double-supported screw fixation (BDSF): (a) preoperative X-ray (b) postoperative X-ray

developed to sort out this issue. This implant combines the best features of the multiple cancellous screws and the sliding hip screw fixation methods. The Aesculap Targon system has been in use in Europe since 2007 [25–27]. (C) The Smith and Nephew Conquest system also has the benefits of the cannulated screw and sliding hip screw fixation, as does the Aesculap Targon system. It consists of a stainless steel plate in left and right specific orientation, one- or three-hole options for proximal screws, and locking or non-locking options for shaft screws. The proximal screws can telescope up to 10 mm for guided compression intraoperatively, and have an integrated internal spring that allows for continued controlled compression postoperatively. It is FDA approved in the USA for intra-capsular femoral neck fractures since 2017 [27]. (D) FNS implant. To deal with high failure rate of conventional implants for these fractures, AO with Depuy Synthes came out with the FNS implant. It consists of an antirotation screw, a bolt, and a side plate with one or two holes. These components are inserted through a targeted insertion handle over one central guide wire. Biomechanical study done by Stoffel et al. showed a significantly higher construct stability compared to three cannulated screws in an unstable femoral neck (Pauwels type III) fracture model. However, no significant difference between the FNS and the DHS systems was observed clinically in this study. Therefore, angle stable devices were recommended for unstable femoral neck fractures [28] (Fig. 4). (E) To avoid shortcoming of high failure rate of multiple cannulated screws due to screw back-out, Mir and Collinge introduced that additional medial buttress plate in case of vertical femoral neck fractures [29]. One-third tubular plate or a medial anatomical buttress plate (MABP) can be used with cannulated screws for this purpose. MABP designed by Li et al. can be used to augment cannulated screws. This combination is a more stable fixation as compared with multiple cannulated cancellous screw or CCS with medial one-third tubular plate, because it perfectly fits with the existing anatomic structure of medial femoral neck [30].

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Fig. 4 Femoral neck system: (a) implant kit includes a bolt antirotation screw and one- or two-hole plate; (b) implant with zig/instrument combination for insertion; (c, d) C-Arm picture: AP and lateral view

(F) Li et al. devised a new fixed angle implant called SCAP-FN (slide compression anatomic place-femoral neck) keeping neck shaft angle of Chinese population (122 on average) in mind. SCAP-FN resists shearing and rotational force better than CCS or DHS+DS on biomechanical study. New design combines features of both CCS and DHS by using three dynamic screws at a fixed angle with a side plate [31].

Neck of Femur Fracture in Pediatric Age Over time poor result of conservative management of pediatric proximal femur fracture was observed. While there was improving results of operative management in adults. Therefore, osteosynthesis with or without hip spica was gradually accepted in pediatric fracture [32]. Cancellous bone screws, pins, and Kirschner wires were commonly used for this purpose.

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Pins and nail (Knowles, Moore, Haggie, Steinman, and ivory): Knowles pins were introduced in 1936. It was chromium-plated steel pins, with a sharp point and threaded at the proximal end. There was a ring on this pin to prevent it from being screwed more inside. On the other hand, Moore pins have a screw thread at the distal end for better purchase. Haggie pins have screw (threads at both ends). Steinman pins (no threads) and ivory pin or a “nail” were not used in the treatment of these fractures. Physiological curvature and narrow dimension of pediatric femoral neck impede insertion of the nail in these fractures [32]. Thick Kirschner wires were also used for internal fixation of the proximal femur. Although as compared with cancellous bone screws and Knowles pins it is less stable. Cancellous bone screws of stainless steel or of Vitallium are also used for better purchase (Fig. 5), although Vitallium screws is often difficult to remove after fracture healing. Intertrochanteric osteotomy and fibular graft transplantation: Allende and Lezame (1951) advised intertrochanteric osteotomy if Pauwels angle is more than 50 with minimal displacement. It should be augmented with fibular graft in case of marked displacement. The paediatric LCP hip plate provides a stable fixation of the

Fig. 5 (a) Preoperative X-ray showing neck of femur fracture; (b) postoperative X-ray showing reduction and fixation with two screws and washer (Rt) femur; and (c) AP and lateral radiograph of pediatric LCP hip plate, which can be used for proximal femur fracture or with inter- and subtrochanteric varus, valgus, and derotation osteotomies. It is an anatomically tailored plate consisting of high level of flexibility

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proximal femoral osteotomy (Fig. 5c). Conservative treatment with hip spica application is suggested if the Pauwels angle is less than 50 [33]. After internal and transepiphyseal fixation of proximal femoral fractures there is still a risk of avascular necrosis or damage to the epiphyseal plate resulting in premature fusion [34]. Growth of granulation tissue from femoral neck into femoral head following internal fixation ensures better vascularization [32].

Arthroplasty German surgeon Themistocles Glück performed the first hip replacement in 1891, in resected tuberculous joints, using an ivory ball and socket fixed to the bone with nickel-plated screws, and provided fixation through a mixture of plaster of Paris and powdered pumice [35]. Failure of these implants due to chronic infection lead to development of the concept of biocompatibility (Table 1). Table 1 Landmarks in arthroplasty [7, 12, 35–42, 45, 47, 62] 1891–1901 1923–1925

Themistocles Gluck Marius Smith Petersen

1938 1938

Judet Philip Wiles

1951 1952 1956–1960 1956–1959 1966– 1977 1970 1971–1980

McKee Lippman Mckee Farrar Shivash Muller

1951 1940 1950

Boutin Pillar and Galante Haboush Moore and Bohlman Thompson FR

1962

Sir John Charnley

1960–1970

Peter Ring

Introduced ivory head to replace the femoral head Created first mould prosthesis out of glass 1930s – Smith-Peterson and Wiles trialled stainless steel prosthesis 1938 – developed Vitallium prosthesis 1970s – developed cemented metal on poly-resurfacing Developed short stemmed acrylic prosthesis Introduced the concept of a femoral head attached to a rod. The first concept of an acetabular reaming was developed, so was born the concept of total hip arthroplasty Develops first cementless metal on metal THR Developed first cemented metal on metal Developed cementless THR Developed curved stem with 28 and 32 mm articulation and later the straight stem Developed ceramic on ceramic and later modular ceramic bearing Introduced the concepts of cementless prosthetic components and the bone growth and pressurization (press fit) Implanted first metal on metal resurfacing First surgeon to replace hips with a metal prosthesis Developed a curved endoprosthesis for sequelae of fracture neck of femur. Later, it was also used for used for fresh fractures Introduced the concepts of low-friction arthroplasty. He used high molecular weight polyethylene associated with methyl methacrylate (cement) and 22 mm femoral head PTFE double cup implant “Greenhouse” clean air enclosure Developed cementless metal on metal

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Reintroduction of ivory as stemmed head to replace native femoral head was done by Ernest W. Hey Groves in 1927 [36].Marius Smith Petersen (1923) developed the idea of using inert material in arthroplasty by serendipity when he observed a synovial sac around a glass piece while excising it from the back. He also observed few drops of clear yellow fluid resembling synovial fluid. He tried glass moulds interposed between the newly shaped surfaces of the head of the femur and the acetabulum. There was high failure rate due to breakage of these moulds. He also investigated Pyrex, Bakelite, etc. A dentist, Cooke, suggested to him Vitallium which proved most biologically tolerant, easily shaped, and had enough strength. Smith-Petersen developed an arthroplasty cup constructed from this material in 1938 [37].The longest reported survival of a Smith-Petersen hip prosthesis was 56 years [38]. Vitallium was also used by Thompson and Moore in the first stems that were fixed with any success to the femoral canal [39]. Harold R. Böhlman in 1939 developed a prosthesis using a CoCr ball fitted to a nail [40]. First biomechanically designed acrylic polyethylene hemiarthroplasty implant was introduced by Jean and Robert Judet in France (1940). There was limited success with this implant, which was replaced by CoCr later [41].Philip Wiles described the first ball and socket implants (THA) that were introduced in 1948, but they failed mechanically after a short time [42]. This first THA was improved by Kenneth McKee [43], but still failed due to loosening and mechanical complications.

Monopolar Prosthesis Monopolar prostheses were starting to gain popularity during 1950s for the treatment of various hip conditions including fractures. There was great contribution of inventing stable metallic monopolar prosthesis by Judet, Thompson FR, and Austin Moore. These implants satisfied the anatomical, functional, and mechanical demands of the hip in a better way. These implants consisted of a head, neck, and a collar with a long intramedullary stem with a neck-shaft inclination angle of 135 degrees for more natural distribution of forces.

Moore Prostheses In 1940, Austin Moore (South Carolina) in collaboration with Bohlman was the first surgeon to replace hips with a metal prosthesis. The patient was first seen in 1934, presenting with a 15-month-old non-union of a femoral neck fracture. After several operations and development of a giant-cell tumor, a wax model was made based on radiographs, and an approximately 12-inch long Vitallium prosthesis with a smooth head was used. A periprosthetic fracture followed that eventually healed. Functional outcome was excellent until the patient died from cardiac failure almost 2 years after the implantation of the prosthesis [44]. The design was improved over time, with two portals in the proximal stem, to fill with autologous bone grafts taken from the extracted femoral head. It allows bone ingrowth and formation of a bone bridge through the prosthesis, thus improving stability [45]. Early results were promising, but complications remained high in several studies throughout the next decades.

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Thompson Prosthesis Thompson developed a curved endoprosthesis for sequelae of fracture neck of femur like non-union and aseptic necrosis. Later, it was widely used for fresh fractures also [46]. British surgeon McKee who first experimented with various uncemented designs further refined the Thompson prosthesis for his cemented total hip arthroplasty design. It was widely used until the discovery of high implant failure [47]. Later Watson Farrar (1960) refined McKee prosthesis [43].

Bipolar Hemiarthroplasty Christiansen (1960) had taken the first steps towards a bipolar hemiarthroplasty in the late 1960s. The Christiansen prosthesis had a built-in trunnion bearing that allowed some movement between the stem and the head of the prosthesis. The results were promising [48], but acetabular protrusion remained a problem. James Ennis Bateman designed a hemiarthroplasty (1974) which was the first true bipolar model with a ball and socket joint between the femoral stem and the prosthetic head [49]. Many series with short- and long-term follow-up showed less pain and decreased protrusion of the acetabulum than the one-piece prostheses. Dr A K Talwalkar bipolar prosthesis was developed to suit the Indian condition. It incorporates the principles laid down by Dr. Bateman. It is a single-unit component, which consists of a stainless steel femoral head captive in high-density polyethylene cup. Stems could be of two types: I) Austin Moore type of stem and II) Thompson type of stem [50].

Cemented Versus Uncemented Hemiarthroplasties Many studies were conducted to compare the result of cemented versus uncemented hemiarthroplasty with majority favouring cemented arthroplasty for fracture neck of femur (Fig. 6) (Table 2). Comparison Between Two Different Uncemented Hemiarthroplasties Livesley (1993) reported better functional outcome with HA-coated implants when he compared 48 hydroxyapatite-coated Furlong bipolar hemiarthroplasties with Fig. 6 AP and lateral radiograph showing cemented modular bipolar prosthesis used to treat neck of femur fracture

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Table 2 Cemented versus cementless hemiarthroplasties

Parker (2010) [51] Foster (2005) [52] Lo (1994) [53] Mayer (1981) [54]

Study design RCT

Retrospective Retrospective Retrospective

Cemented implants Thompson (189)

Cementless implants AMP (189)

Thompson (174) Bateman (190) Christiansen (40)

AMP (70) Bateman (261) AMP (43)

Remarks Cemented group: better functional outcome, mobility, and less pain Cementless group: more risk of periprosthetic fracture Less pain in cemented group Better functional outcome in cemented group

34 Moore bipolars [55]. Bezwada (2004) reported excellent results in a series of 256 Taperloc uncemented bipolar hemiarthroplasties with a proximal press fit design [56]. Cement-related cardiovascular and respiratory complications and fatalities have been well known since the advent of cementing techniques. A cemented femoral stem may be associated with a small increase in mortality compared with an uncemented stem [57].

Total Hip Arthroplasty Sir John Charnley was the pioneer in the development of THR, although initially developed for chronic problem such as osteoarthritis, rheumatoid arthritis, etc. of the hip where the hip joint was beyond salvage. It became an option in the treatment of fracture neck of femur where the hemiarthroplasty was indicated as success for fixation for displaced fractures in the elderly was limited. There were many studies which show better functional result and longevity with use of THR when compared to hemiarthroplasty. THA has been referred to as “the operation of the century”. THA fixation methods are basically divided into two main groups: cemented, using a self-setting acrylic cement as fixation component, and uncemented (Fig. 7). The birth of widespread hip replacement began in the UK in the late 1950s and early 1960s when British orthopedic surgeon Sir John Charnley (cemented stem with metal-on polyethylene-bearing surface) and Peter Ring (uncemented) started hip replacements. German chemist Otto Rohm (1933) invented and reserved the name “PLEXIGLAS” as the first form of industrial use of PMMA, although chemically it was firstly invented in 1877 by the German chemists Fitting and Paul [58]. Nowadays this polymer is available in the following types: a) with a radiolucent barium sulphate and b) with antibiotics. In the cemented arthroplasty stem is circular and bulky in proximal part. Their specially shaped surface with vertical and perpendicular ridges intends to modify the linear forces into compression in the cement-

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Fig. 7 (a, b) Radiographs of cemented total hip arthroplasty: AP and lateral view; (c, d) radiographs showing fracture neck of femur left side treated with hybrid THR

implant surface [58]. The invention and use of cement also modified the biomaterials of the implants. It has been proved that chromium-cobalt alloys mixed with other minor metals had assisted in better application of forces, stabilizing the area, and so they prevailed [59]. In Exeter, England, Prof Robin Ling and Prof Clive Lee were pioneer of double tapered Exeter stem. It has been in use since 1970, with good results [60]. It has one of the highest survivorships in published results [61].

Cementless Arthroplasty Uncemented hip replacement were introduced by Peter Ring. The Ring stem, as metal-on-metal articulation, was introduced in 1962. It performed well and later served as an inspiration for the new generation of metal-on-metal models [62]. Titanium is still preferred metal in cementless arthroplasty because of its property of excellent mechanical strength and biocompatibility [59]. The first use of hydroxyapatite (HA) coating in orthopedics was reported at St Thomas’ Hospital, London [59]. Layer of hydroxyapatite, by means of its absorption, increases the

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contact forces between metal and bone. Uncemented prostheses which allow bone ingrowth have become increasingly popular [63]. The most commonly used uncemented femoral stem in Norway is the Corail stem, with a survival of above 97% after 15 years of follow-up [64]. The articulation has moved from UHMWPE to highly cross-linked polyethylene with either ceramic or cobalt chromium heads as a result of lower wear properties [65]. Similarly, there has been a trend towards using hybrid or reverse hybrid hip replacement where cement is used on one side and on the other side an uncemented prosthesis is used [60]. The modern THA: Evolution and innovation continue to improve implant survival. There are plenty of implants commercially available. However, patient satisfaction is the ultimate key to success. The modern THA typically consists of a femoral stem, a femoral head, and a cup replacing the acetabulum. The femoral neck may be a fixed part of the femoral stem or may be modular with variety of angulations, lengths, and offset of the femoral neck. The femoral head is typically made of metal alloy or ceramics, and the acetabular liner consisting of cross-linked polyethylene or ceramics.

Conclusion Developments and innovations continue to improve implants, either for fixation of these fractures and in arthroplasty. Despite the presence of numerus implants, internal fixation methods, and arthroplasty for the surgical management of femoral neck fractures, the ideal methods of management are still under discussion. The prevalence of osteonecrosis remains high, regardless of the method of osteosynthesis, and the implant used. It is necessary to achieve anatomical reduction wherever possible either by closed or open means and to achieve stable fixation. Older patients are often best served by THR or hemiarthroplasty. Implant selection and timely intervention are critical for both osteosynthesis as well as arthroplasty.

References 1. Speed K. The classic the unsolved fracture. Clin Orthop Relat Res. 1980;152:3–9. 2. Bartonicek J, Vlcek E. Femoral neck fracture–the cause of death of Emperor Charles IV. Arch Orthop Trauma Surg. 2001;121(6):353–4. 3. Cordasco P. Evolution of treatment of fracture of neck of femur. Arch Surg. 1938;37(6): 871–925. 4. Mostof SB. Who’s who in orthopedics. London: Springer; 2005. 5. Sir CA. A treatise on dislocations and on fractures of the joints: fractures of the neck of the thigh-bone. Clin Orthop Relat Res. 2007;458:6–7. 6. Jeannet JP. Osteosynthesis explained. In: Leading a surgical revolution. Cham: Springer; 2019. 7. A treatise on fractures in the vicinity of joints, and on certain forms of accidental and congenital dislocations. Medico-Chir Rev. 1847;6(11):137–152. 8. Bartonícek J. Proximal femur fractures: the pioneer era of 1818 to 1925. Clin Orthop. 2004;419: 306–10.

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9. Markatos K, et al. Hallmarks in the history of orthopaedic implants for trauma and joint replacement. Acta Med Hist Adriat. 2016;14(1):161–76. 10. Johansson S. On the operative treatment of medial fractures of the neck of the femur. Acta Orthop Scand. 1932;3:362–92. 11. Frandsen PA, Andersen PE Jr. Treatment of displaced fractures of the femoral neck. SmithPetersen osteosynthesis versus sliding-nail-plate osteosynthesis. Acta Orthop Scand. 1981;52(5):547–52. https://doi.org/10.3109/17453678108992145. 12. Kamangu M, Burette JL. Cinquante ans de survie d’une prothèse acrylique de Judet [Fifty-year survival of a Judet acrylic prosthesis]. Acta Orthop Belg. 2002;68(4):408–11. 13. Pugh WL. A self-adjusting nail-plate for fractures about the hip joint. J Bone Joint Surg Am. 1955;37-a(5):1085–93. 14. Charnley J. Treatment of fractures of the neck of the femur by compression. J Bone Joint Surg. 1956;388:772. 15. Hargadon EJ, Pearson JR. Treatment of intracapsular fractures of the femoral neck with the Charnley compression screw. J Bone Joint Surg (Br). 1963;45-B:305–11. 16. Brown JT, Abrami G. Transcervical femoral fracture: a review of 195 patients treated by sliding nail-plate fixation. J Bone Joint Surg (Br). 1964;46-B:648–63. 17. Broos PL, Vercruysse R, Fourneau I, Driesen R, Stappaerts KH. Unstable femoral neck fractures in young adults: treatment with the AO 130-degree blade plate. J Orthop Trauma. 1998;12(4):235–9; discussion 240. 18. Watson-Jones R. Fractures and joint injuries. 7th ed. Elsevier; 2009. p. 830–45. 19. Krastman P, van den Bent RP, Krijnen P, Schipper IB. Two cannulated hip screws for femoral neck fractures: treatment of choice or asking for trouble? Arch Orthop Trauma Surg. 2006;126(5):297–303. 20. Rockwood CA, David PG, James DH, Robert W. B. Rockwood and Green’s fractures in adults. Philadelphia: Lippincott Williams & Wilkins; 2011. Print. 21. Hoshino CM, Christian MW, O’Toole RV, Manson TT. Fixation of displaced femoral neck fractures in young adults: fixed-angle devices or Pauwel screws? Injury. 2016;47(8):1676–84. 22. Hawks MA, Kim H, Strauss JE, Oliphant BW, Golden RD, Hsieh AH, et al. Does a trochanteric lag screw improve fixation of vertically oriented femoral neck fractures? Clin Biomech (Bristol Avon). 2013;28:886–91. 23. Brand RA. 50 years ago in CORR: function fixation of femoral neck fractures; telescoping nail technic. William K. Massie MD. CORR 1958;12:230-255. Clin Orthop Relat Res. 2009;467(7): 1929–30. 24. Filipov O. Biplane double-supported screw fixation (F-technique): a method of screw fixation at osteoporotic fractures of the femoral neck. Eur J Orthop Surg Traumatol. 2011;21(7):539–43. 25. Takigawa N, Yasui K, Eshiro H, et al. Clinical results of surgical treatment for femoral neck fractures with the Targon® FN. Injury. 2016;47(Suppl 7):S44–8. 26. https://www.bbraun.com/en/products/b0/femoral-neck-targonfn.html 27. Duffin M, Pilson HT. Technologies for young femoral neck fracture fixation. J Orthop Trauma. 2019;33(Suppl 1):S20–6. https://doi.org/10.1097/BOT.0000000000001367. 28. Stoffel K, Zderic I, Gras F, et al. Biomechanical evaluation of the femoral neck system in unstable Pauwels III femoral neck fractures: a comparison with the dynamic hip screw and cannulated screws. J Orthop Trauma. 2017;31(3):131–7. 29. Mir H, Collinge C. Application of a medial buttress plate may prevent many treatment failures seen after fixation of vertical femoral neck fractures in young adults. Med Hypotheses. 2015;84(5):429–33. 30. Li J, Yin P, Zhang L, Chen H, Tang P. Medial anatomical buttress plate in treating displaced femoral neck fracture a finite element analysis. Injury. 2019;50(11):1895–900. 31. Li J, Zhao Z, Yin P, et al. Comparison of three different internal fixation implants in treatment of femoral neck fracture – a finite element analysis. J Orthop Surg Res. 2019;14:76. 32. Hoekstra HJ. Fractures of the proximal femur in children and adolescents. [S.n.]; 1982. 299 p.

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Implantology of Fractures of the Neck of Femur

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33. Allende G, Lezama LG. Fractures of the neck of the femur in children. A clinical study. J Bone Joint Surg. 1951;33A:387–95. 34. Dial BL, Lark RK. Pediatric proximal femur fractures. J Orthop. 2018;15(2):529–35. https:// doi.org/10.1016/j.jor.2018.03.039. PMID: 29681707; PMCID: PMC5909031. 35. Brand RA, Mont MA, Manring MM. Biographical sketch: Themistocles Gluck (1853–1942). Clin Orthop Relat Res. 2011;469:1525–7. 36. Szostakowski B, Jagiello J, Skinner JA. ArtiFacts: ivory hemiarthroplasty: the forgotten concept lives on. Clin Orthop Relat Res. 2017;475(12):2850–4. 37. Smith-Petersen MN. Evolution of mould arthroplasty of the hip joint. J Bone Joint Surg Br. 1948;30b(1):59–75. 38. Wright DM, Alonso A, Rathinam M, et al. Smith-Petersen mould arthroplasty: an ultralongterm follow-up. J Arthroplast. 2006;21:916–7. 39. Moore AT. Metal hip joint; a new self-locking vitallium prosthesis. South Med J. 1952;45:1015–9. 40. Bohlman HR. Replacement reconstruction of the hip. Am J Surg. 1952;84:268–78. 41. Judet J, Judet R. The use of an artificial femoral head for arthroplasty of the hip joint. J Bone Joint Surg Br. 1950;32-B:166–73. 42. Wiles P. The surgery of the osteoarthritic hip. Br J Surg. 1958;45:488–97. 43. McKee GK, Watson-Farrar J. Replacement of arthritic hips by the McKee-Farrar prosthesis. J Bone Joint Surg Br. 1966;48:245–59. 44. Moore AT, Bohlman HR. Metal hip joint: a case report. 1942. Clin Orthop Relat Res. 2006;453: 22–4. 45. Thompson FR. An essay on the development of arthroplasty of the hip. Clin Orthop Relat Res. 1966;44:73–82. 46. Montgomey SP, Lawson LR. Primary Thompson prosthesis for acute femoral neck fractures. Clin Orthop Relat Res. 1978;137:62–8. 47. McKellop H, Park SH, Chiesa R, Doorn P, Lu B, Normand P, Grigoris P, Amstutz H. In vivo wear of three types of metal on metal hip prostheses during two decades of use. Clin Orthop Relat Res. 1996;(329 Suppl):S128–40. 48. Soreide O, Lerner AP, Thunold J. Primary prosthetic replacement in acute femoral neck fractures. Injury. 1975;6(4):286–93. 49. Bateman JE. The classic: single-assembly total hip prosthesis-preliminary report. 1974. Clin Orthop Relat Res. 2005;441:16–8. 50. Naser, et al. Evaluation of treatment of fracture neck of femur with uncemented bipolar prosthesis. Int J Recent Trends Sci Technol. 2014;12(2):353–7. 51. Parker MI, Pryor G, Gurusamy K. Cemented versus uncemented hemiarthroplasty for intracapsular hip fractures: a randomised controlled trial in 400 patients. J Bone Joint Surg Br. 2010;92(1):116–22. 52. Foster AP, Thompson NW, Wong J, Charlwood AP. Periprosthetic femoral fractures–a comparison between cemented and uncemented hemiarthroplasties. Injury. 2005;36(3):424–9. 53. Lo WH, Chen WM, Huang CK, Chen TH, Chiu FY, Chen CM. Bateman bipolar hemiarthroplasty for displaced intracapsular femoral neck fractures. Uncemented versus cemented. Clin Orthop Relat Res. 1994;302:75–82. 54. Meyer S. Prosthetic replacement in hip fractures: a comparison between the Moore and Christiansen endoprostheses. Clin Orthop Relat Res. 1981;160:57–62. 55. Livesley PJ, Srivastiva VM, Needoff M, Prince HG, Moulton AM. Use of a hydroxyapatitecoated hemiarthroplasty in the management of subcapital fractures of the femur. Injury. 1993;24(4):236–40. 56. Bezwada HP, Shah AR, Harding SH, Baker J, Johanson NA, Mont MA. Cementless bipolar hemiarthroplasty for displaced femoral neck fractures in the elderly. J Arthroplast. 2004;19 (7 Suppl 2):73–7. 57. Parvizi J, Holiday AD, Ereth MH, Lewallen DG. The Frank Stinchfield Award. Sudden death during primary hip arthroplasty. Clin Orthop Relat Res. 1999;369:39–48.

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58. Park J, Lakes RS. Biomaterials- an introduction. 3rd ed. New York: Springer; 2007. p. 9–10. 59. Anderson J, Neary F, Pickstone JV. Surgeons, manufacturers and patients: a transatlantic history of total hip replacement (Science, technology & medicine in modern history). New York: Palgrave Macmillan; 2007. p. 1–18. 60. https://www.bbc.com/news/uk-england-devon-59213835. 61. Ling RS, Charity J, Lee AJ, Whitehouse SL, Timperley AJ, Gie GA. The long-term results of the original Exeter polished cemented femoral component: a follow-up report. J Arthroplast. 2009;24(4):511–7. 62. Ring PA. Replacement of the hip joint. Ann R Coll Surg Engl. 1971;48:344–55. 63. Schwarzkopf R. Modern techniques in Total hip arthroplasty: from primary to complex. 1st ed. Jaypee Brothers; 2014. 64. Hallan G, Lie SA, Furnes O, Engesaeter LB, Vollset SE, Havelin LI. Medium- and long-term performance of 11,516 uncemented primary femoral stems from the Norwegian arthroplasty register. J Bone Joint Surg Br. 2007;89(12):1574–80. 65. Fabry C, Zietz C, Baumann A, Bader R. Wear performance of sequentially cross-linked polyethylene inserts against ion-treated CoCr, TiNbN-Coated CoCr and Al2O3 ceramic femoral heads for total hip replacement. Lubricants. 2015;3:14–26. https://doi.org/10.3390/lubricants3010014.

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nails Without Side Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Static Nails Including Side Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Condylar Blade Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mode of Failure/Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic Nails Including Side Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Trochanteric Buttress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gotfried Percutaneous Compression Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intramedullary Nails for Intertrochanteric Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kuntscher Y Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zickel Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enders Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Third-Generation Intramedullary Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximal Femoral Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximal Femoral Nail Antirotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intertan Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Advanced Trochanteric Fixation (Trochanteric Femoral Nail or TFN) . . . . . . . . . . . . . . . . . . . . . . . Halifax Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Arthroplasty in the Treatment of Intertrochanteric Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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W. Gadegone (*) Gadegone Orthopaedic And Trauma Care Hospital, Chandrapur, India e-mail: [email protected] B. Shivshankar Iyer Orthopaedic Centre, Solapur, Maharashtra, India e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_79

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Abstract

Hip fractures are the most significant public health concern facing orthopaedic surgeons across the globe. The majority of hip fractures in the elderly are low-energy fractures owing to longevity and osteoporosis. Their treatment occupies an increasing proportion of the health care budget. The purpose of treatment is to restore function with as few surgical and medical consequences as feasible. Successful treatment of trochanteric fractures depends on reduction and secure fixation. In the last 70 years, several implants have been developed for the treatment of intertrochanteric fractures of the hip, as well as modifications in implant design to ensure stable fixation and early mobility. With the introduction of science and technology and the improvements in the designs of implant, there is increasing acceptance of intramedullary devices in preference to the sliding hip screw (SHS) for the treatment of intertrochanteric fractures despite little good quality evidence to support their use in most fractures. However, there is a consensus among orthopaedic surgeons worldwide that extramedullary implants are used for stable femoral fractures. This chapter describes several implant designs and their benefits and drawbacks, from basic nail plates to advanced intramedullary implant systems. Keywords

Intertrochanteric fracture · Extramedullary implants · Intramedullary implants · Nail with side plates · Buttress plate · Dynamic Hip Screw · Proximal femoral nail · Arthroplasty

Introduction The incidence of intertrochanteric fractures has grown globally due to increasing life expectancy. 90% of these fractures occur in the elderly after a household fall or minor trauma. The occurrence of this fracture varies from nation to nation. The majority of the senior population is affected by osteoporosis, which causes bone thinning. Elderly patients are more likely to fall and sustain extracapsular and intracapsular femoral neck fractures. In India, specific statistics on intertrochanteric fractures are unavailable, but by 2040, hip fractures would become a serious health concern with socioeconomic consequences. The AO has divided intertrochanteric fractures into two basic categories: stable and unstable. Classification influences the selection of implant and fracture prognosis. For orthopaedic surgeons, the treatment of intertrochanteric hip fractures, particularly the unstable kind, in the elderly remains a difficulty. For the treatment of intertrochanteric fractures, there is no agreement about the optimal implant and procedure to be applied. Surgeons disagree on whether extramedullary or intramedullary implants provide the greatest fixation and result. For some writers, arthroplasty is the treatment of choice for older individuals. To accomplish stable stabilization of hip fractures, therefore, several implants are devised and continual changes are proposed.

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History In the sixteenth century, Ambroise Pare was the first to accurately characterize Proximal femoral fractures. Prior to this, all of these fractures were assumed to be dislocations. In 1851, Cooper distinguished between two kinds of proximal femur fractures: extracapsular fractures that demonstrated union and intracapsular fractures that did not. He recommended bed rest with moderate extension and steady support of the limb in its natural position until pain subsides, followed by the use of crutches and a cane, and then an elevated shoe, all in an effort to save the patient’s life, if not the limb. Cooper asserted that union occurs in patients with extracapsular hip fractures. Whitman (1925) achieved consolidation of fracture in some patients for the first time by reducing the fracture and then placing the patient in a spica cast, a cast that included the trunk, pelvis, and lower limb. At the same time, Codevilla (1904) and later Steinmann (1919) achieved successful results by employing skeletal traction by means of a trans osseous pin in some cases of extracapsular fractures by inserting the pins either through the distal femur. In 1936, Hohenegg summed up the situation as follows: “The hip fracture is a common ailment among the elderly and is often the beginning of the end.” Most patients die from pneumonia, urinary sepsis, or decubitus. To prevent this, clinicians should do their best to get patients out of bed. Axhausen initially discovered evidence of fracture union during an autopsy. He was able to show that a fracture with a completely necrotic head had united [1].

Nails Without Side Plates Trans fixation across fracture to maintain reduced position without compression was the principle of fracture fixation. The first major step in this direction was a three-flanged nail devised by Smith-Petersen in 1925. However, the nail had to be inserted after an arthrotomy. Johansson (1932) used a nail with a central bore and a guide wire. The procedure gained fast acceptance in Europe and permitted surgery even in elderly persons. They were mainly used for intracapsular fracture rather than extracapsular fractures. The following designs of nails were devised: (1) noncannulated nail similar to the Smith-Petersen nail, (2) small, cannulated nail designed by Johansson in 1932, (3) broad flanged nail of L. Bôhler with spikes, (4) Felsenreich nail with broad flanges, (5) Aesculap SP-nail with inner threads at the end, and (6) Thornton nail made from Vitallium (Fig. 1). JW. Davis described the treatment of intertrochanteric fractures with the SmithPetersen nail in 1947 [2]. KM. Lewis described the internal fixation of intertrochanteric fractures with the Smith-Petersen nail and extension bar [3].

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Fig. 1 (a) and (b) Smith Petersen nail and designs

Fig. 2 A Smith Peterson nail with Mclaughlin plate

Static Nails Including Side Plates Thornton was the first to add a plate to the caudal end of the nail. McLaughlin (1947), Massie (1958), and Bohler (1996) created side plates connected to the nail using the same technique. Smith Peterson nail with detachable Mclaughlin plate was used to provide angular stability which may provide increased stability and rigidness to the construct [4] (Fig. 2). Various combined plate-nail systems were developed including (1) Szilagyi nail made in Hungary in 1960; (2) Aesculap nail with plate; (3) nail made in the former

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Fig. 3 (a) Radiograph showing Jewett nail plate; (b) Jewett nail plate

German Democratic Republic; (4) Pugh telescoping nail made from Vitallium allowing a settling [5]; (5) McLaughlin nail with side plate made either from titanium or Vitallium; and (6) Jewett nail-plate. Jewett (1941) developed his nail-plate implant as one piece to provide angular stability and rigid fixation in the treatment of intertrochanteric fractures [6] (Fig. 3).

Condylar Blade Plate In 1977, Muller et al. and the researchers of the AO/ASIF group devised condylar blade plate a static implant which considerably increased the stability of the construct. Further modifications improved the treatment of trochanteric fractures considerably [7]. The 95 Condylar Blade Plate was effective in treating patients with intertrochanteric femoral fractures. Due to the indirect reduction and internal fixation using condylar blade plate, the surgical time and blood loss were minimized. Early patient rehabilitation was initiated, and the complications were decreased (Fig. 4).

Mode of Failure/Disadvantages Angle-stable lateral buttressing plate that allowed backing out, impaction/resorption (settling) at the fracture site, and thus the shortening of the neck. Jewett nail plate frequently perforated the femoral head, especially in elderly patients. In younger patients, this caused a distraction, as the nail had a solid purchase in the strong subchondral bone. This resulted in a non-union and then a fatigue fracture of the nail.

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Fig. 4 (a) and (b) the condylar blade plate and radiograph showing fixation

Dynamic Nails Including Side Plates Putti (1942) was the first to introduce screw fixation instead of rigid nailing. In 1951, Pohl invented a telescoping screw that allowed to compensate for impaction/resorption (settling) of the fracture. This sliding hip screw, later refined in the United States (Schumpelick and Jantzen 1955), permitted auto-compression of a neck fracture. Main purpose of these modified designs were to provide adequate rotational stability via enhanced design and controlled collapse at fracture site acquiring secondary stability to help in union with intraoperative compression of fracture [8] (Fig. 5). DHS is a prototype implant that has withstood the test of time in the last 40 years for management of intertrochanteric fractures. It has also been considered a gold standard for managing stable intertrochanteric fractures, as DHS fixation produces reproducibly reliable results [9, 10]. However, in unstable fractures, the device performs less well, with a higher incidence of internal fixation failure [11, 12]. Failure modes of the Dynamic hip screw include excessive fracture collapse, cutout and plastic deformation of the implant, separation of the side plate from the femoral shaft, fracture of the implant, and disengagement of the cervico-cephalic compression screw from the side plate barrel [13].

Plate Trochanteric Buttress It can be used in unstable trochanteric fractures to provide lateral buttressing to the lateral wall when combined with a Dynamic hip screw. Through the plate, additional fixation can be achieved by inserting screws into the neck and head. This prevents excessive sliding of the dynamic screw, thereby reinforcing the lateral wall. However, the procedure requires a lengthy exposure time and substantial blood loss [14] (Fig. 6).

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Fig. 5 Dynamic hip screw (DHS): (a) DHS systems of various lengths; (b) demonstration of the components of the DHS system; and (c) radiograph showing DHS fixation

Fig. 6 (a) and (b) Dynamic compression screw with trochanteric buttress plate

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Gotfried Percutaneous Compression Plate Gotfried developed the PerCutaneous Compression Plate (PCCP) for minimalapproach osteosynthesis of pertrochanteric fractures, resulting in shorter theatre and surgical time and reduced postoperative pain. The cutout rate was significantly lower than in the DHS group in unstable fractures. However, the PCCP treatment showed a higher mechanical complication rate [15].

Intramedullary Nails for Intertrochanteric Fractures The use of an intramedullary nail for the treatment of proximal femur fractures was proposed to enhance the biological and mechanical properties of the construct. In the beginning, there were two methods of nailing proximal femur, one Y nail of Gerhard Kuntsher and another elastic nailing of Enders.

Kuntscher Y Nail Centromedullary nailing was introduced for the purpose of reducing bending moments compared to surface implants with neck fixation. The beginnings of intramedullary nailing of proximal femoral fractures are connected with the names of G. Kuntscher and R. Maatz. After successfully introducing intramedullary nailing of femoral shaft fractures, Kuntscher, in 1940, developed a conical nail for treatment of proximal femur fractures. This nail was inserted from the apex of the greater trochanter. Shortly afterward, this advance was followed by its modification, the so-called Y-nail, a precursor to the reconstruction nails in present use. In 1962, Kuntscher reversed his approach by inserting the transverse nail into the femoral neck first and then the intramedullary nail from the greater trochanter into the medullary canal. Kuntscher’s modified Y nail is composed of two parts, a fenestrated nail for the neck and an ordinary medullary nail which passed through the hole in the other. The neck nail was oval in cross section in its outermost third and of tapering U section in the remainder of its length. With this technique, Kuntscher later on reported the results of having successfully treated more than 150 pertrochanteric fractures [16, 17] (Figs. 7 and 8).

Zickel Nail In 1967, Zickel described another intramedullary nail. The Zickel nail mirrored the shape of the femoral medullary cavity, with its proximal portion curved in both valgus and anteversion. It consisted of the following three parts: (1) a specially shaped intramedullary rod, [2] a modified Smith Petersen nail that penetrates the rod called a crossed nail, and [3] a set screw. A tri-fin nail was inserted into the femoral head at an angle of 125 with the help of a targeting device and a guidewire

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Fig. 7 Illustration of the use of a Kuntscher Y nail for intertrochanteric fracture of the femur

Fig. 8 Illustration of the modified Y nail

through the medullary nail after reaming. The locking bolt was inserted from the apex of the widened proximal part of the intramedullary nail [18]. Due to the angled and curved nature of the rod, the left and right side nails are also distinct (Fig. 9).

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Fig. 9 Illustration of the Zickel nail in intertrochanteric fracture fixation

Enders Nail Condylocephalic nailing, with a bundle of supple nails, provided a temporary mechanical solution for early weight bearing. This method was received with much enthusiasm, and in the 1970s and 1980s, many proximal femoral fractures (mostly pertrochanteric and subtrochanteric) were treated with Ender nailing, but it was eventually replaced by intramedullary nailing. It is a minimally invasive, costeffective, and weight-bearing early mobilization approach. However, backout of the nails through the femoral condyles, resulting in discomfort and bursitis necessitating removal. Complications such as malunion, unacceptable shortening, implant cutout at the femoral neck, bone flaking, and fracture at the insertion place were reported [19] (Fig. 10).

Third-Generation Intramedullary Nail In an effort to reduce fracture deformity and loss of reduction or fixation, thirdgeneration reconstruction nails for use with a trochanteric entry portal were developed. The principle of this nail was a cephalomedullary nail with a single neck compression screw that could be locked to provide compression as well as rotational stability. The Gamma Nail was designed for the treatment of trochanteric hip fractures in the mid-1980s and was introduced into clinical usage in 1988. It was

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Fig. 10 (a) Enders nails; (b) radiograph showing fixation of a comminuted intertrochanteric fracture with Ender nails

developed by Dr. S. C. Halder in Halifax, United Kingdom, in an effort to solve some of the clinical issues associated with the Zickel nail [20, 21]. The Standard Gamma Nail (SGN) was introduced in 1992 and is used for subtrochanteric hip fractures, femoral shaft fractures, and combined trochanterodiaphyseal fractures of the femur. The Long Gamma Nail (LGN) was introduced in 1992 and is used for subtrochanteric hip fractures, femoral shaft fractures, and combined trochantero-diaphyseal fractures of the femur. The Trochanteric Gamma Nail (TGN), a modified version of the SGN, was created in 1997 by reducing its length by 2 cm, lowering its mediolateral bend from 10 to 4 , and providing just one orifice for distal locking. After more than 15 years of clinical experience, the Gamma 3 nail was developed in 2001 and released in 2003. The proximal diameter of the nail decreased from 17 mm to 15.5 mm without compromising its strength. The patented shape of the strength improvement groove was the main factor allowing minimization of the proximal part of the nail. This screw cannot rotate in the nail due to a locking bolt; however, it can move diolaterally in specially integrated grooves [22] (Figs. 11 and 12).

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Fig. 11 Illustration of first Gamma nail versions

Fig. 12 Illustration and picture of a Trochanteric Gamma Nail

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Proximal Femoral Nail Introducing by AO/ASIF in 1996 with the idea that a single lag screw is unable to withstand the forces of proximal femur and cannot provide rotational stability led to introduction of PFN with 24 cm in length with proximal diameter of 17 mm [23]. Proximal diameter of nail is reduced from 17 mm to 15.5 mm to suit the anatomy of the Asian population. It is commonly used to treat stable and unstable intertrochanteric fractures and available in three forms, long (36–42 mm), standard (24 mm), and short nail (18 mm) [24, 25] (Fig. 13). The advantage of this design is that the addition of a 6.5 mm hip pin acts as a derotation pin, providing additional rotational stability with the possibility for static and dynamic locking. A tapered distal portion of the nail with slots to distribute the bending forces over a longer portion of the femoral shaft, thereby reducing the risk of femoral shaft fracture at the nail tip. However, this nail not only reduced the frequency of intraoperative femoral shaft fractures, but also introduced additional issues, such as screw backing out, Z effect, and reverse Z effect, that led to nail failure [26, 27].

Fig. 13 (a) Illustration of AO/ASIF proximal femur nail. (b) Picture of Asian proximal femoral nails; (c) preoperative and postoperative radiographs showing standard PFN fixation (24 cm length); and (d) preoperative and postoperative radiographs showing short PFN fixation (18 cm length)

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Proximal Femoral Nail Antirotation The AO/ASIF developed the PFNA system in 2004. It was designed with a single head component to counteract the complications of the two-screw device PFN and to provide better rotational stability. The main design characteristic of the implant is the use of a single blade with a large surface area [28]. Main advantage is the compaction of bone by blade insertion rather than removal. The tip of the nail is specially shaped to reduce stress concentration, as in the PFN. Biomechanical tests indicate the blade has a significantly higher cutout resistance than commonly used screw systems. Distal locking can be static or dynamic through a single hole. Possible complications like cut through, cutout of helical blade, backing out, and difficulty to tighten the blade intraoperatively are detriments of the Helical blade method [29]. The newer designs of PFNA nail, instead of helical lade prototype of Gamma screw, can be passed to prevent the penetration in to the hip joint (Fig. 14).

Fig. 14 (a) Illustration of PFNA with helical blade and screw; (b) PFNA with helical blade and screw; (c) postoperative radiograph showing PFNA2 nail with blade Fixation; and (d) postoperative radiograph showing PFNA2 nail with screw fixation

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Fig. 15 (a) Illustration of Intertan nail; (b) radiograph showing Intertan nail being used for fixation of intertrochanteric fracture

Intertan Nail Intramedullary nail with proximal integrated screw design was created by Smith & Nephew and introduced in 2006 to achieve and sustain extremely strong compression throughout fracture site. The integrated compression screws provide a second point of fixation in the femoral head. Strong interfragmentary friction and increases construct stability to resist complications like rotation and varus collapse [30]. Inappropriate reduction and inadequate implant placement may lead to construct failure via cutout, cut through, and implant breakage. Difficult implantation of the nail in patients with changed morphology, resulting in preimplant fractures, is also a problem [31] (Fig. 15).

Advanced Trochanteric Fixation (Trochanteric Femoral Nail or TFN) As the normal femur is a slightly curved bone, a straight nail may not perfectly match the curvature of the femur. To address this issue, the Zimmer Natural Nail or ZNN implant was created (Zimmer, Germany). This innovative form of implant accommodated the proximal femur’s whole anatomical structure. The short nail has a radius of curvature of 1275 mm, an anteversion angle of 15 , and two distinct centre-columndiaphyseal (CCD) angles (125 /130 ). The diameter of the lag screw is 10.5 mm. It has also been shown that ZNN has positive clinical benefits. The nail is side specific because of anatomical configuration of nail. The results of the research comparing PFN A2 and ZNN in terms of hip function have not changed much. Johnson & Johnson’s intramedullary nail, introduced in 2015, closely matches the anatomy with either a helical blade or screw option, with injection cement provided into the femoral head via the blade or screw to increase holding capacity within weak bone. Reduced critical width and lateral relief cut avoids impingement on lateral cortex. Titanium alloy and BUMP CUT Design of proximal hole provide improved fatigue strength compared to existing nails of comparable size. TFNA Helical Blade technology is

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Fig. 16 (a) and (b) illustration of helical blade or screw with cement injection option; (c) and (d) illustration of helical blade or screw with cement injection option; (e) radiograph showing cement augmentation in a patient who underwent fixation with this device

designed to compress bone during insertion, which enhances implant anchorage and may reduce the risk of cutout [32, 33] (Fig. 16).

Halifax Nail The Halifax Nail was developed by Dr. Halder in 2013 to treat both intra- and extracapsular femoral fractures by close reduction and fixation. This new implant is called the Halifax Nail. A set of “Tri-Wire” is incorporated inside the Lag screw. The

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Fig. 17 (a) and (b) show the Halifax hip screw; and (c) radiograph showing Halifax nail fixation

“Tri-wire” extend to the periphery of the femoral head in subchondral bone area to give a better rotational stability to the fracture. However, this nail is recently introduced and there are no reported long-term results [34] (Fig. 17).

Arthroplasty in the Treatment of Intertrochanteric Fractures Vast majority of intertrochanteric fractures treated with some form of internal fixation heal. However, some unfavourable fracture patterns, osteoporosis, and poor hardware placement can lead to fixation failure leading to malunion and nonunion. The purpose of replacing the fractured proximal fragment with a stable prosthesis with reconstruction of the greater trochanter is to make the construct

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stable enough to allow early mobilization with weight bearing (Figs. 17 and 18). A variety of replacement options from cemented to uncemented calcar preserving to calcar replacing, from short stem to long stem, and from bipolar to total hip replacements, coxofemoral by pass, have been tried with success [35, 36].This major surgical procedure in geriatric patients may lead to systemic problems resulting from greater blood loss, prolonged surgery, cementing, dislocations, infection, fixation failure of GT repair, and intraoperative or postoperative periprosthetic fracture [37] (Figs. 18 and 19).

Fig. 18 Preoperative and postoperative radiographs showing cemented bipolar hemiarthroplasty performed for intertrochanteric fracture

Fig. 19 Preoperative and postoperative radiographs showing cemented total hip arthroplasty performed for intertrochanteric fracture

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Conclusion In the past 70 years, extramedullary and intramedullary implants have been developed to treat stable and unstable intertrochanteric fractures, but there is still conflicting evidence to guide the choice of implant for unstable fractures. It is difficult to prove the superiority of extramedullary and intramedullary methods clinically over each other. We believe that, extramedullary and intramedullary, both methods are good alternatives for each other. However, it often requires supplementary implants to achieve stable fixation in both methods. This chapter deals with evolution of implants and their advantages and disadvantages.

References 1. Kazár G, Manninger J. Historical retrospection. In: Manninger J, et al., editors. Internal fixation of femoral neck fractures. Vienna: Springer; 2007. p. 85–103. 2. Davis JW. The treatment of intertrochanteric fractures using the Smith-Petersen nail. N C Med J. 1937;8(9):588–91. PMID: 20263650 3. Lewis KM. Internal fixation using Smith-Petersen nail and extension bar in the treatment of intertrochanteric fractures of the femur; a study of 132 cases. Am J Surg. 1950;80(6):669–79. PMID: 14790108 4. Nielsen BP, Jelnes R, Rasmussen LB, Ebling A. Trochanteric fractures treated by the McLaughlin nail and plate. Injury. 1985;16(5):334–6. 5. Pugh WL. A self-adjusting nail-plate for fractures about the hip-joint. J Bone Joint Surg Am. 1955;37-A:1085–93. 6. Gathercole ANJ, Pena MA. Penetration in trochanteric fractures of the femur treated with rigid nail plates. Injury. 1982;13(5):363–9. MARCH 01, PMID: 7085047 7. Suriyajakyuthana W. Intertrochanteric fractures of the femur: results of treatment with 95 degrees Condylar Blade Plate. J Med Assoc Thai. 2004;87(12):1431–8. PMID: 15822536 8. Sahlstrand T. The Richards compression and sliding hip screw system in the treatment of intertrochanteric fractures. Acta Orthop Scand. 1974;45:213–9. https://doi.org/10.3109/ 17453677408989142. 9. Ecker ML, Joyce JJ 3rd, Kohl EJ. The treatment of trochanteric hip fractures with a compression screw. J Bone Joint Surg Am. 1975;57-A:23–30. 10. Clawson D, Kay MD. Trochanteric fractures treated by the sliding screw plate fixation technique. J Trauma. 1964;4(6):737–52. Williams & Wilkins 1964 11. Kyle RF, Gustilo RB, Premer RF. Analysis of 622 intertrochanteric hip fractures. J Bone Joint Sug Am. 1979;61:216–21. https://doi.org/10.1055/s-0030-1267060. 12. Schipper IB, Marti RK, Werken C. Unstable trochanteric femoral fractures: extramedullary or intramedullary fixation. Review of literature. Injury. 2004;35(2):142–51. https://doi.org/10. 1016/S0020-1383(03)00287-0. 13. Davis TR, Sher JL, Horsman A, et al. Intertrochanteric femoral fractures: mechanical failure following internal fixation. J Bone Joint Surg. 1990;72-B(1) https://doi.org/10.1302/0301620X.72B1.2298790. 14. Madsen JE, et al. Dynamic hip screw with trochanteric stabilizing plate in the treatment of unstable proximal femoral fractures: a comparative study with the gamma nail and compression hip screw. J Orthop Trauma. 1998;12(4):241–8. 15. Kosygan KP, Mohan R, Newman RJ. The Gotfried percutaneous compression plate compared with the conventional classic hip screw for the fixation of intertrochanteric fractures of the hip. J Bone Joint Surg Br. 2002;84(1):19–22. 16. Küntscher G. Die Marknagelung von Knochenbrüchen. Arch KlinChir. 1940;200:443–55. Klinische Wochenschrift, 1940 – Springer

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W. Gadegone and B. Shivshankar

17. Küntscher G (1972) Praxis der Marknagelung. SchattauerVerlag, Stuttgart. Google Scholar. 18. Zickel RE. A new fixation device for subtrochanteric fractures of the femur: a preliminary report. Clin Orthop Rel Res. 1967;54:115–30. 19. Marsh CH. Use of ender’s nails in unstable trochanteric femoral fractures. J R Soc Med. 1983;76(7):550–4. https://doi.org/10.1177/014107688307600705. 20. Halder SC. The gamma nail for Peri trochanteric fractures. J Bone Joint Surg. 1992;74(3): 340–4. 21. Kempf I, Grosse A, Taglang G, Favreul E. Gamma nail in the treatment of closed trochanteric fractures. Results and indications apropos of 121 cases. Revue de Chirurgie Orthopedique et Reparatrice de L’appareil Moteur. 79(1):29–40. PMID: 8284466 22. Abram SG, Pollard TC, Andrade AJ. Inadequate ‘three-point’ proximal fixation predicts Gamma nail failure. Bone Joint J. 2013;95-B(6):825–30. https://doi.org/10.1302/0301-620X. 95B6.31018. 23. Boldin C, Seibert FJ, Fankhauser F, Peicha G, Grechenig W, Szyszkowitz R. The proximal femoral nail (PFN) – a minimal invasive treatment of unstable proximal femoral fractures: a prospective study of 55 patients with a follow-up of 15 months. Acta Orthop Scand. 2003;74(1): 53–8. https://doi.org/10.1080/00016470310013662. 24. Gadegone WM, Salphale YS. Proximal femoral nail – an analysis of 100 cases of proximal femoral fractures with an average follow up of 1 year. Int Orthop. 2007;31(3):403–8. https://doi. org/10.1007/s00264-006-0170-3. 25. Gadegone WM, Salphale YS. Short proximal femoral nail fixation for trochanteric fractures. J Orthop Surg. 2010;18(1):39–44. https://doi.org/10.1177/2309499010018001094. 26. Windolf J, Hollander DA, Hakimi M, Linhart W. Pitfalls and complications in the use of the proximal femoral nail. Langenbeck’s Arch Surg. 2005;371(1):59–65. https://doi.org/10.1007/ s00423-004-0466-y. 27. Strauss EJ, Kummer FJ, Koval KJ, Egol KA. The Z-effect phenomenon is defined: a laboratory research. J Orthop Res. 2007;25(12):1568–73. 28. Xie Y, Dong Q, Xie Z. Proximal femoral nail anti-rotation (PFNA) and hemi-arthroplasty in the treatment of elderly intertrochanteric fractures. Acta Orthop Belg. 2019;85(2):199–204. PMID: 31315010 29. Chapman T, Zmistowski B, Krieg J, et al. Helical blade versus screw fixation in the treatment of hip fractures with cephalomedullary devices: incidence of failure and atypical “medial cutout”. J Bone Jt Surg Am. 2018;90:700–7. PMID: 30035756 30. Jiang Y, Li J, Dib HH, Li YC. Implantation of INTERTAN™ nail in four patients with intertrochanteric fractures leading to single or comminute fractures: pitfalls and recommendations: a case series. J Med Case Rep. 2014;8:383. https://doi.org/10.1186/1752-1947-8-383. 31. Zheng XL, Park YC, Kim S, An H, Yang KH. Removal of a broken trigen itertan intertrochanteric antegrade nail. Injury. 2017;48(2):557–9. PMID: 28041613 32. A Lenich, E Mayr, A Rüter, C Möckl First results with the trochanter fixation nail (TFN): a report on 120 cases. Arch Orthop 2006 126, pages706–712. 33. An Sermon, et al. Impact of bone cement augmentation on the fixation strength of TFNA blades and screws. Medicina. 2021;57(9):899. PMCID: PMC8465598 34. Halder SC. Tips and tricks master of intramedullary nailing, vol. 1. 1st ed. The Royal College of Surgeons of England. 35. Choy WS, Ahn JH, Ko JH, Kam BS. Cementless bipolar hemiarthroplasty for unstable intertrochanteric fractures in elderly patients. Clin Orthop Surg. 2010;2(4):221–6. https://doi. org/10.4055/cios.2010.2.4.221. 36. Sancheti K, Sancheti P, Shyam A, Patil S, Dhariwal Q, Joshi R. Primary hemiarthroplasty for unstable osteoporotic intertrochanteric fractures in the elderly: a retrospective case study. Indian J Orthop. 2010;44:428–34. https://doi.org/10.4103/0019-5413.67122. 37. Bao NR, Zhao JN, Zhou LW, Zeng XF. Complications of bipolar hemiarthroplasty for the treatment of unstable intertrochanteric fractures in the elderly. China J Orthop Traumatol. 2010;23(5):329–31. PMID: 20575280

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Imaging and Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evolution of Surgical Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jewett Nail Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Condylar Blade Plate or Angled Blade Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pugh Nail and Sliding Hip Screw Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic Condylar Hip Screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Medoff Sliding Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Locking Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intramedullary Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kuntscher K Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kuntscher Y Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zickel Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enders Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Russel Taylor Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Third-Generation Reconstruction Nail: Gamma Nail and Halifax Nail . . . . . . . . . . . . . . . . . . . . . . . The Trochanteric Gamma Nail (TGN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximal Femoral Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Proximal Femoral Nail Antirotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Advanced Trochanteric Fixation (Trochanteric Femoral Nail or TFN) . . . . . . . . . . . . . . . . . . . . . . . Trigen Nail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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B. Shivashankar and W. Gadegone

Abstract

Subtrochanteric fractures are a subtype of proximal femur fractures found between the lesser trochanter and 5 cm distal to it. Due to its muscle insertions, the subtrochanteric region of the femur is susceptible to several deforming stresses and is an area of high stress concentration. Due to the prevalence of cortical bone, the subtrochanteric area has a more fragile vascularization than the trans-trochanteric zone, making it more difficult to consolidate fractures. Implantrelated problems and fracture non-union are found to be prevalent in proximal femur fractures with a high reoperation rate. The bimodal occurrence of subtrochanteric fracture in young and elderly patients poses a problem when selecting the optimal implant to restore function with the lowest risk of surgical and medical problems. The undamaged medial and lateral cortex under the lesser trochanter offers a buffer to fracture impaction following fixation, hence preventing its collapse. The degree of comminution of the posteromedial cortex and osteoporotic bone increases the degree of instability. Increased comminution reduces axial loading support via cortical contact. A fracture is rendered unstable if any of these cortical areas is deficient. Implant fixation aims to produce stable reduction and fixing of the fracture, allowing for rapid mobilization. The orthopaedic community continues to discuss the reasoning for the design of extramedullary fixation for subtrochanteric fractures of the femur. Subtrochanteric fractures have been treated using intramedullary devices (SHS, condylar blade plate, and proximal femoral locking plate) rather than extramedullary implants (SHS, condylar blade plate, and proximal femoral locking plate) over the last 25 years. This chapter discusses the reasons for and suggestions for implant changes, as well as the implant of choice currently in use. Keywords

Subtrochanteric fractures · Extramedullary implants · Intramedullary implants · Enders nails and proximal femoral nails

Introduction The subtrochanteric area of the femur is the proximal femoral shaft lying within 5 cm of the lesser trochanter. Subtrochanteric fractures are frequently found in elderly individuals with osteoporosis after low-energy trauma and in younger patients with high-energy trauma (Fig. 1). The subtrochanteric region of the upper femur is the strongest cortical bone region in the body and is subject to the greatest stress pressures. Muscle attachments cause the concentration of tension. The iliopsoas is responsible for flexion, the

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Fig. 1 Illustration of subtrochanteric region of femur B. Radiograph showing subtrochanteric fracture

gluteus medius for abduction, and the external rotators for external rotation. As the adductors are joined further distally, the proximal pieces of these fractures tend to move in varus. The majority of cortical bone, which must support all these stresses, has a tenuous vascularity, which makes healing and consolidation of fractures in this region problematic, particularly if medial cortical support is absent [1]. Therefore, even the toughest of implants may fail in this area. Fractures in this region may result in considerable problems and poor clinical results, including failure of fixation, shortening, malrotation, and non-union, if not correctly handled and if incorrect implants are used [2, 3]. Therefore, fractures in the subtrochanteric region of the femur provide a challenging treatment challenge for the orthopaedic surgeon. Since the 1940s, many techniques of internal fixation have been developed for the treatment of these fractures. The purpose of this page is to discuss the development of different nail plates, compression screws with side plates, and intramedullary devices used to treat subtrochanteric fractures.

Imaging and Classification Initial imaging of a patient with a suspected subtrochanteric fracture consists of an AP pelvic film and a full-length femur film. These early imaging studies will allow for accurate injury diagnosis and fracture classification. The significance of finding atypical fractures linked with bisphosphonates stems from the fact that there is a significant prevalence of bilateral fractures that can be detected and diagnosed with

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great accuracy. Advanced imaging modalities, such as CT or MRI, may be used to discover hidden fractures in circumstances when plain radiographs are ambiguous. Classification of fractures is necessary for determining the implant of choice for a given fracture type. The most notable categories are the Russel Tylor Classification, Seinsheimer’s Classification, and AO Classification, which number over 15 kinds. Russel Taylor’s classification takes into account fractures affecting the piriformis fossa or the trochanteric fossa, as they were categorized based on the implants available at the time to treat these fractures and to provide guidelines for implant utilization in such fractures. Fractures of type I do not involve the trochanteric fossa (Type IA) without extension to lesser trochanter and (Type IB) with extension to lesser trochanter. Fractures of type II extend to the trochanteric fossa (Type IIA without comminution of lesser trochanter and Type IIB with comminution of lesser trochanter). The categorization of Seinsheimer fractures is determined by the fracture’s location, pattern, amount of displacement, and degree of comminution. There are five kinds of fractures. This classification is beneficial because it detects fractures with lack of medial stability (types IIIA and IV) that have a higher risk of healing problems. The AO’s exhaustive classification is based on fracture pattern and degree of comminution. It does not account for the amount of displacement. The range of this classification is 32 AI to 32 C3. With the aging of the population and the prevalence of high-velocity injuries in younger patients, many fractures cannot be precisely categorized into a single kind, and the classification may not be able to advise the surgeon in implant selection for a specific variation. Therefore, the authors consider that there is no definitive categorization available for these fractures, and they have selected the AO/OTA Classification to facilitate communication. [4] In the previous 80 years, several extramedullary and intramedullary implant types have been developed for the treatment of subtrochanteric fractures.

Evolution of Surgical Implants There are many varieties of extramedullary and intramedullary implants available for treating subtrochanteric fractures in the last 80 years.

Jewett Nail Plate Eugene Jewett introduced and published the first one-piece flanged hip nail in the Journal of Bone and Joint Surgery in October 1941. This nail is now commonly known as the Jewett Nail. From the 1940s until the 1970s, this implant was widely utilized for subtrochanteric fractures with positive outcomes. Although it offered

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Fig. 2 (a) Picture of Jewett nail plates (b) Radiograph showing Jewett nail plate fixation (Incidentally a broken guide wire is present in the femoral head at the tip of the Jewett nail)

appropriate attachment of the proximal fragment and stability of the fracture to the shaft with a plate, it did not permit fracture impaction; as a result, intra-articular migration, screw cutout, and implant distortion were frequent. Overall, Jewett nail plate fixation for subtrochanteric fracture had unsatisfactory outcomes (Fig. 2).

Condylar Blade Plate or Angled Blade Plate The introduction of the AO/ASIF 95 fixed angled condylar blade plate in 1970 was introduced for the treatment of unstable trochanteric and subtrochanteric fractures. This design permitted further calcar screw fixation in the proximal fragment for acute high-energy proximal femur fractures, including subtrochanteric fractures. The 95 condylar blade plate provided sufficient attachment, and a high rate of union was observed. This system needed precise blade positioning in three dimensions and a very challenging technique. The use of laterally based plate and screw structures, such as the sliding hip screw and angled blade plate, has dropped progressively during the last two decades. Certain injuries may be best treated with plate fixation, such as fractures extending into nail entry sites in the proximal femur and extensively displaced high-energy injuries with a simple fracture pattern amenable to open reduction, anatomical reduction, and fracture site compression. This serves as a reminder to the orthopaedic trauma community that the 95 angled blade plate is still an outstanding therapeutic choice for adequately chosen fractures when applied correctly [5] (Fig. 3).

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Fig. 3 A Picture of condylar blade plate designs B Radiograph showing condylar blade plate fixation for subtrochanteric fracture

Pugh Nail and Sliding Hip Screw Plate The sliding nail, invented by Willis Pugh [6] in the mid-1950s particularly for intracapsular fractures, seemed to solve some of the issues associated with fixedtype devices. These nails, created specifically for femoral neck fractures, might let fracture collapse and avoid penetration into the joint. To prohibit rotation of the nail, a keyway was incorporated into the inner surface of the tube, and a pin or key was attached to the nail section to correspond with the keyway. A friction ring was also placed toward the distal end of the nail to provide tension, preventing the nail from backing out of the head in the case of absorption near the end of the nail. The friction ring is crucial because it provides the appropriate gap between the nail and the tube, allowing the nail to glide and guaranteeing adjustability by preventing binding. Friction ring offered the most suitable, simple, and practical method for constructing an internal fixation that is adjustable and can be relied upon in every instance not to bind, while still providing sufficient resistance to prevent the flanged portion of the nail from backing, or failing, out of the head. The length of the tube or barrel of the barrel plate is enough to alleviate side stress and avoid binding. Experiments with engineers revealed that short tube construction could not accomplish full sliding inside the tube when side push was met, thus a long tube angle support or brace was developed. In response to reports from Germany regarding the Pohl gliding screw plate and following a conversation with Ian McKenzie about his similar screw, this type of apparatus, manufactured by Richards Manufacturing Company in Memphis, Tennessee, became the standard method for treating trochanteric fractures. This sliding hip screw is also often referred to as Richards hip screw and sliding hip screw, based on the first major manufacturer and its sliding mechanism, respectively. Dynamic hip screw/sliding hip screw has been widely used to fix subtrochanteric fractures, despite being designed for the treatment of intertrochanteric fractures. However, due to the biomechanics of subtrochanteric fractures, Joglekar et al. [7] reported unsatisfactory

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Fig. 4 A Picture of dynamic hip screw and plate sliding hip screw B Radiograph showing DHS plate fixation for subtrochanteric fracture

results due to uncontrolled medialization in over 70% of their cases because DHS was a dynamic system. This increasing, uncontrolled medialization of the diaphysis led to fixation failure (Fig. 4).

Dynamic Condylar Hip Screw The AO group developed the dynamic condylar screw to facilitate the application across the condylar blade plate. The dynamic condylar screw is a two-part device with a similar design to the condylar blade plate. Following reaming and tapping, the screw is installed on the guide wire. This implant became popular due to the simplicity of screw insertion in the neck and head and its capacity to address varus and valgus as well as flexion and extension malalignment. With this implant, the purchase of a screw for the neck is preferable to the purchase of a condylar blade plate. However, additional screws are necessary for rotational stability in addition to the dynamic screw. With the emergence of the dynamic hip screw, however, the use of dynamic condylar screws was limited to indirect reduction and fixation of subtrochanteric fractures. Implants were a promising alternative for treating subtrochanteric fractures, particularly when indirect reduction and biological fixation techniques were used. Even though DCS and blade plates are less expensive, they continue to be among the most effective treatments for subtrochanteric fractures, particularly when minimally invasive procedures are used. The typical open reduction and internal fixation often leads to devascularization, an increase in infection rates, and failure of osteosynthesis. The 95 dynamic condylar screw and the angled blade plate were produced (by AO / AISF) as an alternative to the early implants and remained the basis for producing more successful results while new nail designs were also developed. Although technically hard, the angled blade plate has remained an outstanding device for surgeons familiar with this implant, particularly when utilized with tissue-sparing procedures [8] (Fig. 5).

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Fig. 5 (a) and (b) Pictures of dynamic condyle hip screw (c) Radiograph showing condylar screw fixation of comminuted subtrochanteric fracture

Fig. 6 Illustration of Medoff sliding plate

Medoff Sliding Plate In 1996, Lunsjo et al. [9] from Sweden introduced the Medoff sliding plate (MSP) as a novel device for treating intertrochanteric and subtrochanteric fractures. There were three sliding options: along the shaft, the neck of the femur, or a combination of the two. The higher dynamic capability afforded by the MSP’s combined compression decreases the danger of problems. The series’ low rate of technical failure compares well to that of the sliding hip screw and the Gamma nail. They proposed that randomized studies comparing the MSP with alternative hip screw systems are essential to determine the real function of the MSP and its sliding modes (Fig. 6).

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Locking Plates Andrew H Schmidt from Minneapolis created an anatomical proximal femoral locking plate in 2007 for unstable intertrochanteric and subtrochanteric fractures with lateral wall involvement in which the use of blade plates was technically difficult and sliding hip screws caused collapse, shortening, and rotational deformity due to the instability of the sliding device or progressive deformity due to rotational instability of the proximal fragment. Due to a lack of experience with conventional fixed angle plates and the rising popularity of locking plate technology, many proximal femoral fractures are treated using locking plates (PFLPs). Early biomechanical data, familiarity with locking technology, and the capacity for percutaneous insertion led to broad acceptance and usage. Multiple studies, however, have shown poor clinical success with the use of PFLPs for proximal femur fractures, making this a less-than-ideal treatment for these troublesome fractures. Due to the significant risk of complications associated with PFLPs, their usage in primary surgery is limited. In recent years, the proximal femoral locking compression plate (PF-LCP) has been used; nevertheless, few papers have indicated positive outcomes, particularly in bones of high quality. Authors such as Saini et al. [10] assert that biological fixation with PF-LCP in comminuted subtrochanteric fractures promotes stable fixation, with a high rate of consolidation and a low rate of complications, despite the fact that numerous articles demonstrate failures in cases treated with PF-LCP, particularly in elderly osteoporotic bones. According to Wirtz et al. [11], the most significant consequences of PF-LCP are infection, cutout, and varus collapse, which need further surgical procedures. These authors underlined that, unlike intramedullary implants, PF-LCPs do not permit fracture collapse, which is essential for fracture consolidation in the absence of posteromedial support (Fig. 7).

Intramedullary Implants Intramedullary fixation and stabilization is one of the most effective methods. As it has biomechanical benefits over other types of surface fixation, interlocking nailing has become the most popular method of fixation for these fractures, with a lower rate of fixation failures and non-unions. Intramedullary devices have the benefit of permitting indirect fracture reduction while retaining vascularity in the fracture zone. At the fracture site, reaming may also induce periosteal response and autogenous graft material. The ability to insert the device percutaneously may save surgical time, and studies have shown that intramedullary devices result in much reduced intraoperative blood loss compared to plate structures. In addition, intramedullary nails are load-sharing implants that may permit sooner postoperative weight-bearing and rehabilitation. Contrary to plate devices, intramedullary devices span the whole femur without substantial soft tissue incision,

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Fig. 7 (a) Illustration of proximal femoral locking plate (b) Radiograph showing proximal femoral locking plate fixation for subtrochanteric fracture

enabling simultaneous treatment of damage to the distal femoral shaft. These intramedullary nails use a piriformis or trochanteric entry site, but their proximal interlocking fixation secures the femoral neck and head. It has been shown that they provide improved biomechanical fixation for subtrochanteric fractures with considerable comminution at the level of the lesser trochanter or in patients with severe osteopenia. Constant advancements in the design of intramedullary implants have led to their classification as first-, second-, and third-generation implants. First-generation femur nails were only useful for fractures extending beyond the lesser trochanter; hence, Russel Taylor invented second-generation femur nails in the early 1990s. In a series of over 200 subtrochanteric fractures treated with reconstructive nails, Russell and Taylor reported a 100% union rate without serious complications, and additional studies have recorded comparable favourable outcomes. Subtrochanteric fractures with extensive trochanteric and piriformis fossa comminution complicate the application of a cephalomedullary device. In these instances, insertion of the nail through these locations may trigger further displacement of the intertrochanteric fracture components. When a fracture extends into the entrance point, the nail may move posteriorly via the fracture site. Excellent clinical and radiological outcomes have been shown in studies involving the use of cephalomedullary implants for fractures affecting the entrance site [12]. Intramedullary devices have technical drawbacks due to the deforming stresses operating on the proximal fragment. Abduction of the proximal fragment makes it difficult to locate a beginning point and often necessitates the use of lateralized guide wires and reamers. In addition, bending of the proximal fragment by the iliopsoas

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might induce excessive reaming of the proximal fragment’s posterior cortex. There may be a need for further procedures to acquire and sustain reduction for passage of the intramedullary device. These include trocars with pointed tips, fracture manipulation using Schanz pins, and fracture site opening with provisional fixation. After intramedullary fixation of subtrochanteric fractures, residual apical anterior angulation with bending of the proximal fragment is a drawback of these implant devices. For subtrochanteric fracture nailing, lateral placement of the patient under traction is advised. By bending the afflicted extremity at the hip, reduction of the fracture may be easily aided and nail insertion can be made simpler.

Kuntscher K Nail Gerhard Kuntscher wrote for the first time in 1940 from the University Clinic in Kiel about the usage of his unique cloverleaf nail in 132 instances, which he named hip nail at the time (Arch. f. Klin. chir. 200: 443, 1940). These nails were often utilized for fractures of the femoral shaft, particularly high-stress areas such as subtrochanteric fractures. Kuntscher later improved these nails to treat proximal femoral fractures in particular.

Kuntscher Y Nail Kuntscher created a conical nail for treating fractures of the proximal femur. This nail was inserted from the greater trochanter’s apex. This innovation was quickly followed by its modification, the so-called Y-nail, a forerunner to the current reconstruction nails. A 32-cm-long U-shaped intramedullary nail was inserted into the medullary cavity of the femoral shaft from the apex of the greater trochanter. This nail featured a hole 8 cm from its proximal end for inserting a shorter (11.5 cm) transverse nail with a double T shape. This transverse nail was inserted at an angle of 135 into the femoral neck and head with the aid of a targeting device connected to the diaphyseal nail. Kuntscher used highly sophisticated tools for their time (Fig. 8).

Zickel Nail In 1967, Robert E Zickel [13] from New York designed a combination of intramedullary rod which can accommodate a nail in the head and neck, which consisted of three parts: (1) a specially shaped intramedullary rod, (2) a modified Smith Petersen nail that penetrates the rod called a crossed nail, and (3) a set screw. The proximal portion of the intramedullary rod is large and square to accommodate the wide greater trochanteric medullary canal, and then it tapers conically to create a long, square intramedullary stem. The big proximal section is equipped with a

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Fig. 8 (a) and (b) Illustration of Kuntscher Y Nail and modified Kuntscher Y Nail

slanted tunnel to accommodate the cross nail. When seen from the side, the rod is likewise curved to match the natural anterior bow of the femoral shaft. The intersection of the rod’s stem and conical parts has a valgus angle of 12 when seen from the front. The unusual cross nail has three fins that are placed in the head, but laterally it is a cylinder with four circumferential grooves that allow a set screw to be installed from the top using an Allan screwdriver. To interact with these grooves, a tiny set screw is inserted into a threaded hole at the top of the rod. This threaded hole also assists to situate the driver during intramedullary rod insertion. Due to the angled and curved nature of the rod, the left and right side nails are also distinct (Fig. 9).

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Fig. 9 Illustration of the design and placement of Zickel nail

Fig. 10 (a) Enders nail. (b) Preoperative and postoperative radiographs showing fixation by Enders nailing

Enders Nailing The year 1969 saw the introduction of a second intramedullary nailing technique by Ender and Simon-Weider, based on Hackethal’s principles and concepts (Fig. 10). In the 1970s and 1980s, numerous proximal femoral fractures (mainly pertrochanteric and subtrochanteric) were treated by Enders nailing. However, the procedure caused significant difficulties in patients with unstable fractures, and it

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was eventually abandoned. Few benefits of condylocephalic nails were decreased deep wound infection, surgical time, and intraoperative blood loss. The disadvantages of these condylocephalic nails, which include an increased rate of femoral head cut through and reoperation rates, as well as limb length shortening and external rotation deformity in over 30% of cases, etc., exceed their benefits, leading to their disfavour. A study of the literature reveals no substantial series of subtrochanteric fractures treated with flexible intramedullary nailing alone [14].

Russel Taylor Nail The second generation of interlocking nails, which were stronger than slotted nails of the same thickness and had a tubular cross-section, were launched as Russel Taylor nail with proximal locking into the head and neck. For the treatment of proximal third femoral fractures, these nails gained popularity quite fast. The diameter of these nails was reduced by a technique known as crimping, which increased their strength, resulting in smaller diameter nails with the strength of larger diameter nails. As these nails were straight, they were passed through the piriform fossa entry way in the same manner as conventional femur nails (Fig. 11).

Third-Generation Reconstruction Nail: Gamma Nail and Halifax Nail Dr. Subhsah Halder of Halifax [15], UK, invented a nail in the mid-1980s, had it produced by Howmedica, and exhibited his work between 1986 and 1988 under the moniker Halifax nail. During the same time period, a comparable nail was produced

Fig. 11 (a) Picture of Russel Taylor nail (b) Radiograph showing fixation with Russel Taylor nail

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and sold in Strasbourg, France, based on the design of the Halifax nail. After a series of clinical studies and adjustments to both implants and equipment, a single design emerged in 1992 and was called Gamma nail for greater acceptability [16] Following this, “The Standard Gamma Nail” (SGN). The long Gamma nail (LGN) was invented in 1992 for the treatment of subtrochanteric hip fractures, femoral shaft fractures, and combination of trochantero-diaphyseal fractures of the femur. In the 1990s, this Gamma nail with a single neck compression screw that can be locked and provides compression as well as rotational stability became popular.

The Trochanteric Gamma Nail (TGN) A modified version of the SGN was created in 1997 by reducing its length by 2 cm, lowering its mediolateral bend from 10 to 4 , and leaving just one hole for distal locking via which both static and dynamic locking may be accomplished. After more than 15 years of clinical experience, the development of the third generation of gamma nail began in 2001, and the Gamma 3 nail was introduced in 2003. The nail’s proximal diameter was reduced from 17 mm to 15.5 mm without losing its strength. The patent-protected form of the strength-improving groove was the primary reason in the proximal nail length reduction. The diameter of the anchor screw was reduced from 12 mm to 10.5 mm. These nails are offered with 120 , 125 , and 130 neck shaft angles, and the distal locking screw has been reduced from 6.28 to 5 mm (Fig. 12).

Fig. 12 Trochanteric Gamma nail versions

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Fig. 13 (a) Picture of proximal femoral nail (b) Preoperative and postoperative radiographs showing proximal femoral nailing performed for subtrochanteric fractures

Proximal Femoral Nail In 1996, the proximal femoral nail (PFN) was created as an intramedullary device for the treatment of such fractures, in response to the increasing problems associated with the conventional Gamma nail (peri-implant fracture, superior cutting of single neck screw, etc.). [17] In addition to all of the advantages of an intramedullary nail, it has a number of other advantageous characteristics, including the ability to be dynamically locked, a tapered design that facilitates the nail’s passage, stress distribution over a larger area to prevent peri-implant fracture, an additional de-rotational screw that prevents the cutting through of neck screws, early mobilization, high rotational stability, and minimal soft tissue damage. With this, an analysis of the union of the subtrochanteric fracture treated internally with PFN was conducted. The universal straight PFN became the implant of choice for intertrochanteric and high subtrochanteric fractures, while the side-specific long PFN with an anterior curve that matches the natural femoral bow became the implant of choice for subtrochanteric fractures [18]. Proximal diameter of nail is reduced from 17 mm to 15.5 mm to suit the anatomy of the Asian population and available in three forms, long (36–42 mm), standard (24 mm), and short nail (18 mm). (Fig. 13).

Proximal Femoral Nail Antirotation Several examples of the Z-effect, reflecting lateral migration of the lag screw and perforation of the femoral head by the antirotation screw due to varus collapse of the head neck fragment, were connected with the proximal femoral nail. In order to

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Fig. 14 (a) Illustration of PFNA with helical blade and screw, (b) PFNA with helical blade and screw

address this issue, the proximal femoral nail antirotation (PFN-A) was designed with a helical neck blade that is inserted by impaction to create bone compaction around the blade, therefore retarding rotation and varus collapse. In biomechanical experiments comparing the fixation stability of the standard lag screw design to that of the helical blade system, inferior femoral head displacement was shown to be greatly reduced with the helical blade system. This reduces the possibility of subsequent displacement (Fig. 14).

Advanced Trochanteric Fixation (Trochanteric Femoral Nail or TFN) As the normal PFN and PF were curved, a straight nail may not perfectly match the curvature of the femur. To address this issue, the Zimmer natural nail or ZNN implant was created (Zimmer, Germany). This innovative form of implant accommodated the proximal femur’s whole anatomical structure. The short nail has a radius of curvature of 1275 mm, an anteversion angle of 15 , and two distinct centre-column-diaphyseal (CCD) angles (125 /130 ). The diameter of the lag screw is 10.5 mm. It has also been shown that ZNN has positive clinical benefits. The results of the research comparing PFN A2 and ZNN in terms of hip function have not changed much [19] (Fig. 15).

Trigen Nail Trochanteric antegrade entrance was used to build a novel device for the treatment of mostly intertrochanteric fractures that utilizes two cephalocervical screws in an integrated mechanism that permits linear intraoperative compression and rotational stability of the head/neck fragment. The Trigen Intertan nail (Smith & Nephew,

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Fig. 15 Trochanteric fixation nail

Fig. 16 (a) Illustration of Intertan nail; (b) and (c) Preoperative and postoperative radiograph showing fixation of subtrochanteric fracture with Intertan nail

Memphis, Tennessee) [20] was released in 2005, and according to the manufacturer, the nail’s form is intended to improve stability and provide more resistance to implant cutout. Although the piriformis fossa entrance site is readily accessible when the patient is lateral, it is often more difficult to identify when the patient is supine. This is particularly true for obese people, hence the proximal lateral bend of this nail was engineered to assist insertion into the greater trochanter. Theoretically,

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this design lowers the risk of varus malalignment and fracture comminution that was previously seen with straight nails introduced via this entrance point. The trapezoidal form of the proximal portion of the nail with cervical with integrated neck screws and a slot for passing the second screw will result in linear compression owing to differential pitch (Fig. 16).

Conclusion Subtrochanteric fractures are subject to high compression pressures applied from the medial direction and tensile stresses from the lateral direction; hence, reduction and maintenance of reduction following fixation are usually challenging. Various extramedullary and intramedullary implants have been explored during the last 70 years, but there is no ideal answer, and typically additional surgeries are required to establish secure fixation. This chapter discusses the development of different implants, as well as their pros and downsides, in order to avoid any issues that might result in implant failure. The intramedullary approach of subtrochanteric fracture fixation is better to the extramedullary method because it offers protection against varus angulation. However, it is difficult to demonstrate the clinical advantage of one approach over the other.

References 1. de Toledo Lourenço PRB, Pires RES. Subtrochanteric fractures of the femur: update. Rev Bras Ortop. 2016;51(3):246–53. https://doi.org/10.1016/j.rboe.2016.03.001. 2. Nordin M, Frankel VH. Basic biomechanics of the musculoskeletal system. 4th ed. Baltimore: Lippincott Williams & Wilkins, A Wolters Kluwer Business; 2012. p. 84–5. Google Scholar 3. Bedi A, Le Toan T. Subtrochanteric femur fractures. Orthop Clin North Am. 2004;35(4): 473–83. PMID: 15363922 4. Rizkalla M, Nimmons SJB, Jones AL. Classifications in brief: the Russell-Taylor classification of subtrochanteric hip fracture. Clin Orthop Relat Res. 2019;477(1):257–61. https://doi.org/10. 1097/CORR.0000000000000505. 5. Berkes MB, Schottel PC, Weldon M, Hansen DH, Achor TS. Ninety-five degree angled blade plate fixation of high-energy unstable proximal femur fractures results in high rates of union and minimal complications. J Orthop Trauma. 2019;33(7):335340. https://doi.org/10.1097/BOT. 00000000000015059. 6. Pugh WL. A self-adjusting nail-plate for fractures about the hip joint. J Bone Joint Surg Am. 1955;37(5):1085–109. 7. Joglekar SB. Contemporary management of subtrochanteric fractures. Orthop Clin. 2015;46(1): 21–35. https://doi.org/10.1016/j.ocl.2014.09.001. PMID: 25435032 8. Pai C-H. Subtrochanteric femur fractures with greater trochanteric extension treated with a dynamic condylar screw. J Orthop Trauma. 1996;10(5):317–22. https://doi.org/10.1097/ 00005131-199607000-00005. PMID: 8814572 9. Lunsjo K, Ceder L, Stigsson L, Hauggaard A. Two-way compression along the shaft and the neck of the femur with the medoff sliding plate: one-year follow-up of 108 intertrochanteric fractures. J Bone Joint Surg Br. 1996;78(3):387–90. https://doi.org/10.1302/0301-620X.78B3. 0780387.

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10. Saini P, Kumar R, Shekhawat V, Joshi N, Bansal M, Kumar S. Biological fixation of comminuted subtrochanteric fractures with proximal femur locking compression plate. Injury. 2013;44(2):226–31. https://doi.org/10.1016/j.injury.2012.10.037. PMID: 23200761 11. Wirtz C, Abbassi F, Evangelopoulos DS, Kohl S, Siebenrock KA, Krüger A. High failure rate of trochanteric fracture osteosynthesis with proximal femoral locking compression plate. Injury. 2013;44(6):756. https://doi.org/10.1016/j.injury.2013.02.020. PMID: 23522837 12. Garrison I, Domingue G, et al. Subtrochanteric femur fractures: a review of the current treatment. EFORT Open Rev. 2021;6(2):145–51. https://doi.org/10.1302/2058-5241.6. 200048. PMID: 33828858 13. Zickle RE. A new fixation device for subtrochanteric femoral fractures: an preliminary report. Clin Orthop. 1967;54:115. Lippincott-Raven Publishers 14. Steen Jensen J, Sonne-Holm S. Critical analysis of ender nailing in the treatment of trochanteric fractures. Acta Orthop Scand. 1980;51(1–6):817–25. https://doi.org/10.3109/ 17453678008990879. 15. Halder SC. Gamma nail treatment for Peritrochanteric fractures. J Bone Joint Surg Br. 1992;74: 340–4. https://doi.org/10.1302/0301-620X.74B3.1587873. PMID: 1587873 16. Borens O, et al. Long gamma nail in the treatment of subtrochanteric fractures. Arch Orthop Trauma Surg. 2004;124(7):443. https://doi.org/10.1007/s00402-004-0711-4. PMID: 15243759 17. Maa K-L, et al. Proximal femoral nails antirotation, Gamma nails, and dynamic hip screws for fixation of intertrochanteric fractures of femur: a meta-analysis. Orthop Traumatol Surg Res. 2014;100(8):859–66. https://doi.org/10.1016/j.otsr.2014.07.023. PMID: 25453927 18. Gadegone WM, Salphale YS. Proximal femoral nail – an analysis of 100 cases of proximal femoral fractures with an average follow up of 1 year. Int Orthop. 2007;31(3):403–8. https://doi. org/10.1007/s00264-006-0170-3. PMID: 16823585 19. Chen J, Zuo CH, et al. Comparison of two cephalomedullary nails (zimmer natural nail and proximal femoral nail antirotation) in the treatment of intertrochanteric fractures in the elderly. Beijing Da Xue Xue Bao Yi Xue Ban. 2019;51(2):283–7. https://doi.org/10.19723/j.issn.1671167X.2019.02.016. 20. Ruecker AH, Rupprecht M, Gruber M, et al. The effectiveness of an intramedullary nail with integrated cephalocervical screws and linear compression in the treatment of intertrochanteric fractures. J Orthop Trauma. 2009;23(1):22–30. https://doi.org/10.1097/BOT. 0b013e31819211b2. PMID: 19104300

Implantology of Fractures of the Shaft of Femur Including Segmental and Combination Fractures

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Historical Perspective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operative Treatment of Femoral Shaft Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Fixation of Femoral Shaft Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intramedullary Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special Situations: Segmental Fractures and Combined Fractures of the Hip and the Shaft of Femur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Femoral shaft fractures are major injuries and are associated with many complications. The treatment evolved over many centuries with surgeons tried to stabilise the fracture with various means. The historical aspect of this treatment evolution has been discussed in detail. The biomechanical rationale for the choice of various implant has been discussed. Locking intramedullary nails are the implant of choice in most of the scenarios, with plates and external fixators having few indications. The design of interlocking intramedullary nails is also changing over time and the current generation nails are capable of treating periarticular fractures as well. Keywords

Femur fracture · Femoral shaft fracture · Internal fixation · Interlocking nail · Plates · External fixator

S. Misra (*) Manipal Hospital, Kolkata, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_80

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Introduction Fracture shaft of femur, usually caused by high energy trauma, is frequently associated with considerable blood loss leading to hypovolemic shock, multiple other injuries, open wounds, pulmonary dysfunction and multiple organ failure. Many aspects of this injury can be life-threatening and deserve early and informed attention. After the introduction of intramedullary nailing by Kuntscher during Second World War, outcome and survival have improved to a great extent. With better understanding of patho-mechanics of femoral shaft fracture combined with improvement of nailing technique, we have been able to treat these fractures with increasing success and lower complication rate.

Historical Perspective Treatment of fracture shaft femur before the Second World War was mainly conservative barring few unsuccessful attempts of intramedullary fixation. Aztec physicians used wooden sticks in the intramedullary canal as fracture stabiliser [1]. From the middle of nineteenth century till the first decade of twentieth century, intramedullary fixation of fracture femur was attempted with ivory pegs. The majority of this fixation technique was reported in German literature [2, 3]. In 1890, Gluck reported first interlocking device, where and intramedullary ivory contained holes at the end for passage of ivory pins [4]. In 1897, Nicolaysen of Norway described the biomechanical principles of intramedullary fixation [5]. He proposed that the length of intramedullary device should be maximised to achieve better fixation. The first recognised attempt of internal fixation with metal rod was done by Hey Groves from Bristol, England, during World War I. He used nails of varied design particularly in patients with gunshot wounds and also for non-unions [6, 7]. His technique appeared to have many complications like reaction, metal failure and infection and was not accepted universally. Smith-Petersen in 1931 reported successful use of stainless steel nail for fixation of fracture neck of femur and following this, use of stainless steel nail for intramedullary fixation expanded rapidly [8]. Kuntscher in 1940 reported his experience of intramedullary fixation of fracture shaft of femur with intramedullary rod [9]. Kuntscher was inspired by intramedullary fixation of fracture neck of femur by Smith Petersen and designed V shaped nail which was subsequently modified to cloverleaf design (Fig. 1). The nail was initially used by open method and insertion through fracture ends. With advent of radiographic control, he refined his technique to perform closed antegrade nailing. He advocated the use of guide wire through small incision in the region of greater trochanter and reaming the canal over the guide wire. This enabled him to use large diameter nail with proper intramedullary fit. Development of metallurgy has also enabled him to fabricate his nail with good quality stainless steel. This experience of Kuntscher marked the beginning of golden era of intramedullary fixation of fracture shaft of femur.

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Fig. 1 Demonstration of a Kuntscher nail and the cloverleaf cross section of the nail

During the same period in the USA, intramedullary fixation of femur was started by Leslie Rush [10]. He used thin rod to achieve three-point fixation. He first developed the system in 1938 and reported his 30 years of experience of treating 190 closed femoral shaft fractures in 1968 with no infection and only two non-union. His outstanding experience unfortunately has not been reproduced by others. A similar system which does not attempt very stable fixation was Ender’s pins which were passed either antegrade or retrograde. Rod migration and unacceptable motion at fracture site are frequent complications of these methods. The Hansen-Street nail was introduced in the USA in 1947. It was a diamond-shaped solid nail designed to resist rotational force by compressive fit achieved in cancellous bone [11]. In the 1960s with the enthusiasm of compression plating, further development of nailing took a backseat. More and more fractures were fixed with plates. Despite this, cephalomedullary nail was first introduced in this decade. Zickel nail came in 1967, which has a hole in the proximal portion, so that another nail can be inserted to head and neck through lateral cortex. A set screw, which is present in all current generation nails, could be inserted through the proximal portion of the nail to prevent back out of the head and neck nail [12]. More and more complications of compression plating started pouring in, and renewed interest in the development of nailing technique appeared in 1970s and 1980s. Important development in this period was interlocking nails, which used locking screws or bolts through the nail proximally and distally to provide rotational stability to the nail-bone construct. The AO and Gross-Kempf nails were front runners. They were slotted cloverleaf shaped interlocking nails. This design of interlocking nail was predominant for many years and provided solution to most of the femoral shaft fractures. Brumback and colleagues reported 98% union rate in statically locked reamed interlocking nailing in 87 femur fractures [13–15]. Further development was to replace the slotted cloverleaf design to non-slotted design to increase torsional rigidity (Fig. 2). Titanium nail came in 1990s, and it gradually became the metal of choice for future nails. Cephalon-medullary nails came like the Gamma nail [16]. Locking options improved with time. Multiplanar, multidirectional locking options are now available at both ends of the nail. Nail design modified according to the entry point of the nail. We have options for trochanteric fossa entry as well as greater trochanter entry. The greater trochanter entry nails have a proximal lateral angulation for ease of insertion and to

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Fig. 2 Non-slotted anatomically curved locking femoral nail (AO) conforming to the anterior curvature of the femur

accommodate in the femoral canal. New nail came for retrograde entry through knee [17]. All these developments allowed the surgeon to use interlocking nail for proximal and distal femoral shaft fractures. In 1999, Brumbck and associates studied and published data of immediate weightbearing in comminuted femoral shaft fracture fixed with intramedullary nailing. They concluded that immediate weightbearing is possible in these fractures fixed with large diameter interlocking nails, and this allows rapid mobilisation of trauma patients with multiple injuries of the extremities [18].

Operative Treatment of Femoral Shaft Fracture External Fixation of Femoral Shaft Fracture External fixator is very rarely used as definitive form of treatment, but it has certain defined indications. In a polytrauma situation, for rapid stabilisation of the femoral fracture, an external fixator is used as part of damage control orthopaedic surgery (Fig. 3) [19, 20]. In high-grade open fractures with severe soft tissue damage and contamination, external fixator is applied for stabilisation of bone and soft tissue and facilitation of repeated soft tissue inspection and debridement (Fig. 4). In femur fractures associated with vascular injury, external fixator can be applied to stabilize the fracture prior to vascular repair. It is also used in infected non-union which require implant holiday. In all these indications, external fixation is used as temporising device and later converted to internal fixation as soon as feasible. Disadvantages of external fixation are due to its long-term use. Pin track infection [21] and scarring of iliotibial band and quadriceps [22] are common complications. Implants required for external fixation are 5 mm schanz pins with minimum of four pins, two on either side of the fracture. Pins can be placed anteriorly, anterolaterally, or laterally, depending on the situation and fracture location. Clamps and rods depend on the system used. The commonly used system has tubular rods of varying sizes with universal and tube to tube clamps (Fig. 5). For more stronger construct, Orthofix device can be used (Fig. 6).

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Fig. 3 A knee-spanning external fixator being used for multiple fractures of the limb

Fig. 4 A knee-spanning external fixator being used for a high-grade open fracture of the femur

Plate Fixation Plate fixation as a routine method of treatment has few indications. When compared with nailing, plate fixation has certain disadvantages. It requires an extensive exposure with more bleeding and increased chance of infection. Fracture biology is disturbed. Injury to quadriceps muscle occurs with subsequent scaring and knee stiffness. Plates are load-bearing device so it is difficult to weight bear on the limb

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Fig. 5 Components of an external fixator Fig. 6 Illustration of an Orthofix device

before fracture union. In spite of these drawbacks, there are certain situations where plating is required. Femur with narrow canal is difficult to nail. Fracture in presence of previous malunion or deformity is an indication of plate fixation. Shaft fractures with proximal or distal femoral fracture can be treated with plates. Femoral shaft fracture associated with unstable pelvis fracture may necessitate plating to avoid

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Fig. 7 Design of the DCP – superior surface (a) and undersurface (b)

Fig. 8 Design of the LCDCP – superior surface (a) and undersurface (b)

Fig. 9 Design of an LCP and illustration of the degree of its conformance to the shaft of femur

placing the patient on traction table. Periprosthetic or peri-implant fractures also require plating. In the presence of associated vascular injury requiring repair, plating is a convenient option. In femoral shaft, non-union plating is sometimes used in combination with nail for increased stability [23]. Broad or narrow dynamic compression plate (DCP) (Fig. 7) or limited contact DCP (Fig. 8) were the implants used for femur fractures from the 1970s till the end of 1990s. The design of DCP and LCDCP allowed compression across the fracture according to AO principle of absolute stability. They also allowed placement of screws without compression across the fracture. Subsequently these plates were replaced by locking compression plate (LCP) in the first decade of twenty-first century. LCP allows screws to be placed for compression of fractures and as well as locking screws through their dynamic compression unit (Fig. 9). This makes the implant suitable for use in both simple fractures as well as multi-fragmentary fractures. The plate can be straight or anatomically curved (Fig. 10) to fit the femoral bow. There are two techniques of applying plates for femur fractures, one is the open method and the other is the submuscular method using minimally invasive plate osteosynthesis (MIPO) technique. Technique is chosen depending on the fracture configuration. A simple fracture pattern requiring accurate reduction, direct open method with compression plating as per AO principle is advisable (Fig. 11). For multi-fragmentary fracture bridge plating technique is advisable to protect the vascularity of the fragments and submuscular plating is recommended in this

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Fig. 10 Design of an anatomically curved LCP and illustration of the degree of its conformance to the shaft of femur

Fig. 11 Simple fracture in deformed femur with narrow medullary canal, treated with open compression plating with LCDCP

scenario (Fig. 12). Minimally invasive technique preserves more blood supply to soft tissue than open technique [24]. For periprosthetic fractures, there are special locking screws available, called periprosthetic screw. These screws have blunt tip to prevent damage to the implanted prosthesis. There are also special attachment plates called locking attachment plate

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Fig. 12 Multi-fragmentary femoral shaft fracture with pelvic injury treated with MIPO plating

Fig. 13 Locking attachment plate with multiple screw options for periprosthetic fractures

designed for periprosthetic fractures to increase fixation around prosthetic stem. These plates can be attached to the LCP with limbs go around for screw fixation in different planes (Figs. 13, 14 and 15).

Intramedullary Nailing Nailing is a natural choice for the treatment of fractures of the femoral shaft due to its tubular anatomy and relatively uniform medullary canal. Except a few instances, most femoral shaft fractures can be successfully treated with medullary nailing (Fig. 16). Intramedullary nails are load-sharing device and a statically locked nail can take loads many times the patient’s body weight. For this biomechanical property, patients can be mobilised early with full weight bearing on the treated

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Fig. 14 Locking attachment plate – black arrow

limb. Contraindications to intramedullary nailing are narrow medullary canal (Fig. 11), pre-existing deformity like malunion. Periprosthetic fractures around femoral stem cannot be treated with nailing. Shaft fractures with extension to proximal or distal part can sometimes pose difficulty to nailing. Closed nailing of the femur is commonly performed through antegrade approach, entry through pyriform fossa [25] or greater trochanter tip [26] (Fig. 17). In some situations, nailing can be done through retrograde approach, with entry through the intercondylar area of the femur [27] (Fig. 18). Nails are designed to accommodate the natural anterior curvature of femur. Radius of curvature of intramedullary nail of femur varies from 1000 to 2000 mm across various manufacturer. Studies of nail curvature and its effect on nail position in the femur found that nails with smaller radius of curvature have more central placement in distal femur, thereby avoiding anterior cortical impingement and sometimes perforation. So newer design nails have less radius of curvature. Nails

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Fig. 15 Periprosthetic screw – white arrow

Fig. 16 Bilateral femoral shaft fractures treated with bilateral interlocking nailing with transverse locking option

designed to go through piriform fossa are straight at the proximal end (Fig. 19), while nails with greater trochanter entry have 4–6 lateral bend (Figs. 20 and 21). Locking options have also evolved with time. Antegrade nails can have multiple locking options proximally with screws going to femoral neck and head, screws from greater trochanter to lesser trochanter, and also standard transverse static and dynamic locking options (Figs. 22 and 23).

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Fig. 17 Antegrade nailing done by pyriform fossa entry (a) and through greater trochanter entry (b)

Fig. 18 Retrograde nailing – entry through intercondylar area

There are many combinations by which these options can be exercised. Distal locking options have also changed over time. From two transverse locking options, it has been changed to multi-angular locking options and thereby making antegrade nails suitable for distal 1/3 femoral shaft fractures. Different multi-directional locking options are very useful for multi-fragmentary fractures with distal and proximal extension (Figs. 24 and 25). Multi-angular locking also increases stability of construct in osteoporotic fractures and non-unions.

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Fig. 19 Straight nail used for piriform fossa entry

Fig. 20 Nail with 6 lateral bend used for greater trochanter entry

Nails with retrograde entry (Fig. 26) have a straight or 5–10 distal posterior bend at the driving end for ease of insertion. Indications of retrograde nailing [28] can be multiple injured patients, bilateral femoral fractures, distal femoral shaft fractures (Figs. 27 and 28), morbid obesity, pregnancy, associated spine and pelvis fractures, ipsilateral femoral neck fractures, ipsilateral tibia or patella fractures, and ipsilateral through knee amputation. Retrograde nails have different distal locking options

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Fig. 21 Illustration of entry points and angle of the pyriform-entry nail and the greater trochanter-entry nail

Fig. 22 Antegrade Femoral Nail (A2FN Synthes) with cervical locking option

Fig. 23 Femoral Reconstruction Nail (FRN Synthes) with multidirectional proximal and distal locking option

available in the form of spiral blade or multi-angular locking for enhanced distal stability. Femoral non-union sometimes require combined fixation with intramedullary nail and plate for enhanced stability and compression across the non-union (Fig. 29).

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Fig. 24 Comminuted fracture of the shaft of femur nailed with multidirectional proximal and distal locking (FRN)

Fig. 25 Comminuted fracture of the shaft of femur nailed with locking screw to neck of femur (A2FN)

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Fig. 26 RAFN Synthes (Retrograde Antegrade Femoral Nail) with multidirectional and spiral blade locking options

Fig. 27 Segmental distal femoral shaft fracture treated with retrograde entry femoral nail and spiral blade locking option

Femoral non-union requires longer time to unite and combined fixation fares better than single implant in these situations.

Special Situations: Segmental Fractures and Combined Fractures of the Hip and the Shaft of Femur These are complex injuries and need special mention. Segmental fractures are usually very high-energy injury and the reduction of the intermediate segment requires special tricks either intramedullary (Fig. 30) or extramedullary. Sometimes need mini open reduction of the segment. Internal fixation is usually with either antegrade or retrograde reamed nailing. Careful reaming of central fragment is necessary to avoid further vascular damage. The fragment is sometimes controlled by external clamps and

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Fig. 28 Distal femoral shaft fracture with articular extension fixed with retrograde entry femoral nail with multidirectional locking

Fig. 29 Combination of nail and plate for femoral non-union

reamer is gently manoeuvred through the fragment. If the segmental fragment is multifragmentary, it may require wiring along with nailing (Fig. 31). The incidence of ipsilateral hip fracture with femoral shaft fracture varies from 1% to 10% across literature [29, 30]. Many of these hip fractures are minimally displaced and can be missed (Figs. 32 and 33) in 30–57% cases [31, 32]. Among many available internal fixation options, the two most common approaches are to use to separate implants for two fractures or use of single implant for both fractures. When two separate implants are used, hip is fixed with cannulated screw or side plate and compression screw and femur is fixed with retrograde nail or plate (Figs. 34 and 35). This approach yielded good outcome [33, 34]. Otherwise, a reconstruction nail can be used to fix

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Fig. 30 Intramedullary reduction technique of segmental fracture with reduction device

Fig. 31 Fragmented segment, wired and nailed

both the fractures. The use of reconstruction nail in these situations has been reported with higher incidence of non-union and loss of fixation of femoral neck fracture and therefore not the favoured implant for most of the surgeons [35, 36].

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Fig. 32 Missed femoral neck fracture (black arrow) with segmental femoral shaft fracture salvaged with cannulated screws to neck of femur

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Fig. 33 Missed hip fracture, displaced after femoral nailing, salvaged with revision nailing

Fig. 34 Ipsilateral intertrochanteric and segmental shaft of femur fractures treated with two separate implants – DHS and retrograde femoral nail with successful outcome

Conclusion Implants for femoral shaft fracture continues to evolve. Intramedullary nailing is natural choice for fracture shaft femur management due to its tubular anatomy and being a load-sharing device. The development of femoral nails has gone through many stages, and currently, surgeons have lot of choices in terms of antegrade or retrograde entry, locking options and biomaterials. Research is ongoing in making nails more suitable for periarticular fractures. Plates have few indications like deformity, narrow canal and non-union. External fixator is used as a damage control device in polytrauma scenario or temporising device in a high-grade open fracture.

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Fig. 35 Combined femoral shaft fracture and intertrochanteric fracture, fixed with retrograde entry femoral nail and dynamic hip screw fixation (DHS)

References 1. Farill J. Orthopedics in Mexico. J Bone Joint Surg Am. 1952;24:506–12. 2. Konig F. Uber die Implantation von Elfenbein zum Ersatz von Knochen und Gelenken. Nach experimentellen und klinischen Beobachtungen. Beitr Klin Chir. 1913;85:91–114. 3. Bircher H. Eine neue Methode unmittelbarer Retention bei Fracturen der Rohrenknochen. Arch Klin Chir. 1886;34:410–22. 4. Gluck T. Autoplastic transplantation. Implantation von Fremdkörpern. Berl Klin Wochenschr. 1890;19:421–7. 5. Nicolaysen J. Lidt on Diagnosen og Behandlungen av. Fr colli femoris. Nord Med Ark. 1897;8:1. 6. Hey Groves EW. On the application of the principle of extension to comminuted fractures of the long bone, with special reference to gunshot injuries. Br J Surg. 1914;2(7):429–43. 7. Hey Groves EW. Ununited fractures with special reference to gunshot injuries and the use of bone grafting. Br J Surg. 1918–1919;6:203–47. 8. Smith-Petersen MN. Intracapsular fractures of the neck of the femur. Treatment by internal fixation. Arch Surg. 1931;23:715–59. 9. Küntscher G. Die Marknalung von Knochenbruchen. Langenbecks. Arch Klin Chir. 1940;200: 443–55.

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10. Rush LV, Rush HL. A technique for longitudinal pin fixation of certain fractures of the ulna and of the femur. J Bone Joint Surg. 1939;21:619–26. 11. Street DM, Hansen HC, Brewer BJ. The medullary nail. Presentation of a new type and report of 4 cases. Arch Surg. 1947;35:423. 12. Zickel RE. A new fixation device for subtrochanteric fractures of the femur: a preliminary report. Clin Orthop Relat Res. 1967;54:115–23. 13. Brumback RJ, Reilly JP, Poka A, et al. Intramedullary nailing of femoral shaft fractures. Part I: decision-making errors with interlocking fixation. J Bone Joint Surg Am. 1988;70:1441–52. 14. Brumback RJ, Uwagie-Ero S, Lakatos RP, et al. Intramedullary nailing of femoral shaft fractures. Part II: fracture-healing with static interlocking fixation. J Bone Joint Surg Am. 1988;70:1453–62. 15. Brumback RJ, Ellison TS, Poka A, et al. Intramedullary nailing of femoral shaft fractures. Part III: long-term effects of static interlocking fixation. J Bone Joint Surg Am. 1992;74:106–12. 16. Stapert JW, Geesing CL, Jacobs PB, et al. First experience and complications with the long gamma nail. J Trauma. 1993;34:394–400. 17. Lucas SE, Seligson D, Henry SL. Intramedullary supracondylar nailing of femoral fractures. A preliminary report of the GSH supracondylar nail. Clin Orthop Relat Res. 1993;296:200–6. 18. Brumback RJ, Toal TR, Murphy-Zane MS, et al. Immediate weight-bearing after treatment of a comminuted fracture of the femoral shaft with a statically locked intramedullary nail. J Bone Joint Surg Am. 1999;81:1538–44. 19. Broos PL, Miserez MJ, Rommens PM. The monofixator in the primary stabilization of femoral shaft fractures in multiply-injured patients. Injury. 1992;23(8):525–8. 20. Nowotarski PJ, Turen CH, Brumback RJ, Scarboro JM. Conversion of external fixation to intramedullary nailing for fractures of the shaft of the femur in multiply injured patients. J Bone Joint Surg Am. 2000;82(6):781–8. 21. Dabezies EJ, Ambrosia RD, Shoji H, Norris R, Murphy G. Fractures of the femoral shaft treated by external fixation with the Wagner device. J Bone Joint Surg Am. 1984;66(3):360–4. 22. Alonso J, Geissler W, Hughes JL. External fixation of femoral fractures. Indications and limitations. Clin Orthop Relat Res. 1989;241:83–8. 23. Christiano Saliba Uliana CS, Fernando Bidolegui F, Kojima K, Giordano V. Augmentation plating leaving the nail in situ is an excellent option for treating femoral shaft nonunion after IM nailing: a multicentre study. Eur J Trauma Emerg Surg. 2021;47(6):1895–901. 24. Farouk O, Krettek C, Miclau T, Schandelmaier P, Guy P, Tscherne H. Minimally invasive plate osteosynthesis: does percutaneous plating disrupt femoral blood supply less than the traditional technique? J Orthop Trauma. 1999;13(6):401–6. 25. Papadakis SA, Shepherd L, Babourda EC, et al. Piriform and trochanteric fossae. A drawing mismatch or a terminology error? A review. Surg Radiol Anat. 2005;27(3):223–6. 26. Ricci WM, Schwappach J, Tucker M, et al. Trochanteric versus piriformis entry portal for the treatment of femoral shaft fractures. J Orthop Trauma. 2006;20(10):663. 27. Herscovici D Jr, Whiteman KW. Retrograde nailing of femur using an intercondylar approach. Clin Orthop Relat Res. 1996;332:98–104. 28. Ostrum RF. Retrograde femoral nailing: indications and techniques. Oper Tech Orthop. 2003;13(2):79–84. 29. Alho A. Concurrent ipsilateral fractures of the hip and the shaft of the femur: a systemic review of 722 cases. Ann Chir Gynaecol. 1997;86(4):326–36. 30. Watson JT, Moed BR. Ipsilateral femoral neck and shaft fractures: complications and their treatment. Clin Orthop Relat Res. 2002;399:78–86. 31. Alho A. Concurrent ipsilateral fractures of hip and femoral shaft: a meta-analysis of 659 cases. Acta Orthop Scand. 1996;67(1):19–28. 32. Yang KH, Han DY, Park HW, et al. Fracture of the ipsilateral neck of the femur in shaft nailing: the role of CT in diagnosis. J Bone Joint Surg Br. 1998;80(4):673–8.

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33. Chen CH, Chen TB, Cheng YM, et al. Ipsilateral fractures of the femoral neck and shaft. Injury. 2000;31(9):719–22. 34. Swiontkowski MF. Ipsilateral femoral shaft and hip fractures. Orthop Clin North Am. 1987;18(1):73–84. 35. Bedi A, Karunaker MA, Caron T, et al. Accuracy of reduction of ipsilateral femoral neck and shaft fractures – an analysis of various internal fixation strategies. J Orthop Trauma. 2009;23(4): 249–53. 36. Sing R, Rohilla R, Magu NK, et al. Ipsilateral femoral neck and shaft fractures: a retrospective analysis of two treatment methods. J Orthop Traumatol. 2008;9(3):141–7.

Implantology of Fractures of the Distal Femur

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Open Reduction and Internal Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Angle Blade Plate and Dynamic Condylar Screw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distal Femur Locking Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modern Locking Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distal Femoral Locking Compression Plate (DFLCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Variable Angle Locked Compression Plate (VA-LCP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plate Length and Screw Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Far Cortical Locking Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . New Implant Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . New Plate Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dual Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intramedullary Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nail + Plate Construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Distal Femoral Replacement (DFR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Distal femur fractures represent a notorious yet common injury pattern accounting for 0.4–1% of all fractures. Managed conservatively in the past, surgical fixation is the gold standard accepted treatment modality in the modern orthopaedic practice. Although several implants are currently available for osteosynthesis in distal femur fractures, none has proven preeminence over the

V. Trikha (*) JPNATC, AIIMS, New Delhi, Delhi, India e-mail: [email protected] A. Gupta Orthopaedics, AIIMS, New Delhi, Delhi, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_81

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other. Anatomical periarticular locking lateral plate is the most frequently used implant in ORIF of these fractures, but high complications rates led to the advent of newer treatment modalities. Dual plating, retrograde nailing, and nail-plate construct encompass some of the recent developed techniques that have significantly improved the clinical outcomes in complex distal femur fractures. Furthermore, improvements in implant material and design have led to more biological fixation rather than merely fixing the fracture fragments anatomically. Distal femur replacement is another recent technique that provides a viable treatment option in carefully chosen patients. Keywords

Distal femur fracture · Retrograde nailing · Distal femur replacement · Anatomical plates · DCS · Angled blade plate

Introduction Fractures of the supracondylar and intercondylar region of the femur constitute distal femoral fractures. Although not as frequent as proximal femoral fractures, fractures of distal femur account for 0.4–1% of all bony injuries and about 3–6% of all femur fractures [1]. These fractures occur in a bimodal distribution: (i) young male patients present following high velocity trauma secondary to a motor vehicle accident or a history of fall while, (ii) elderly patients particularly females present after a low energy trauma such as fall from standing height [1]. Of peculiar importance is the rising incidence of the periprosthetic fractures around distal femur. The incidence of distal femur fractures subsequent to a primary total knee replacement has been described to be around 0.3–5.5%, and this percentage can reach up to 30% ensuing a revision knee arthroplasty [2]. Till 1970, majority of the distal femur fractures were managed conservatively; however, better understanding of fracture healing, alarming incidence of angular deformities, post-traumatic arthritis, joint stiffness, limb length discrepancy, as well as complications associated with prolonged recumbency led to improved modalities of treatment [3, 4]. During the past five decades considerable improvement in the operative techniques and implants have led to internal fixation as the standard of care for treatment of most distal femur fractures. The goals of management involve AO principles of anatomic reduction of the joint surface, restoration of limb length, alignment and rotation, and stable fixation that permits early mobilization and in turn timely rehabilitation. Despite phenomenal advancements in the available instrumentation and implant designs, surgical fixation of distal femur fractures remains challenging. Osteopenia, fracture comminution, articular involvement, complex anatomy, associated injuries around knee, and wide medullary canal make stable internal fixation often arduous to accomplish. Although, newer and better fixation modalities have markedly improved the clinical outcomes, the operative management of this notorious injury pattern is ever evolving.

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Open Reduction and Internal Fixation Since the 1970s, with the availability of newer and more reliable implants, better understanding of operative techniques and refined anaesthetic modalities, open reduction and internal fixation (ORIF) has gained widespread popularity for nearly all displaced distal femur fractures. Among the first implants used for management of such injuries were the 95* fixed angled devices including condylar blade plates (CBP) and dynamic condylar screw (DCS), rush rods, zickel devices, compressionscrew apparatus, and supracondylar plates [5]. However, fixed angled devices ubiquitously dominated the era before the early 2000s for fixation of most distal femoral fractures. Relatively frequent complications [5] including infection, nonunion, malunion (predominantly varus collapse), need for bone grafting, joint stiffness, post-traumatic arthritis; inability to address comminuted intra-articular fractures, poor functional outcomes, and development of AO techniques paved the way for introduction of anatomical distal femoral locking plates (DFLP). Ease of operative technique and improved clinical outcomes made DFLP universally accepted for fixing such fractures. In accordance with AO’s principle of preservation of vascular supply and to minimize the soft tissue trauma Less Invasive Stabilization System (LISS) (Synthes USA) and Minimal Invasive Plate Osteosynthesis (MIPO) techniques were developed. These techniques gained rapid popularity and became increasingly accepted. Simultaneously, building on this concept, manual/ percutaneous reduction along with retrograde femoral nailing became an established modality for fixing of distal femur fractures. This allowed for minimally invasive implant insertion that decreased soft tissue stripping and lowered intra-op haemorrhage and surgical duration. Fixed screw construct in traditional DFLP and insufficiency to stabilize complex fractures led to development variable angle locking DFLP. Also, high incidence of non-union or delayed union, implant failure, and varus collapse in fractures with medial comminution foreshadowed the development of dual plating and plate-nail constructs in distal femur fractures. In cases with severe osteoporosis, comminution, preexistent joint arthritis, or periprosthetic fractures, distal femur replacement (DFR) has been introduced by the reconstructive surgeons and has begun to play a significant role in the management of acute distal femur fractures [6]. Despite eminent evolution of the implants and the operative techniques, the optimal implant of choice remains elusive. Novel ideas comprising newer implant materials with better modulus of elasticity and improved plate designs are currently being investigated for improved fracture healing and eventually better clinical outcomes.

Angle Blade Plate and Dynamic Condylar Screw Dynamic Condylar Screw (DCS) and 95* Angled Blade Plate (ABP) (Fig. 1) dominated the surgeons’ armamentarium for fixation of distal femur fractures before the twenty-first century. Classic indications include extra-articular fractures, sagittal

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Fig. 1 (a) Angle Blade Plate, (b) Dynamic Condylar Screw

split unicondylar fractures and supracondylar as well as minimally comminuted intercondylar fractures.In the present-day context, these historical implants are mainly reserved for stabilization of malunions and non-unions. Instead of distal femoral fractures, currently they are rather increasingly used in the management of neglected proximal femoral fractures. The accurate placement of these devices is technically challenging and more so for ABP as it requires precise placement of the blade in all three planes simultaneously. The “summation technique” has been the most consistent method described for insertion of either the condylar screw or the blade. It employs three guide wires where the first wire is placed parallel to the tibiofemoral joint line, the second wire is positioned parallel to the patellofemoral joint while the third or the “summation” wire parallels the aforementioned wires, starting 1.5–2 cm above the tibiofemoral joint line in the anterior half of the femoral condyles. In case of ABP, a seating chisel is inserted whereas a triple reamer similar to a DHS is used for placing a condylar screw. This is followed by application of the plate and securing the shaft to the barrel plate with 4.5 mm cortical screws. Minimal inaccuracy in blade or the screw placement can result in uncorrectable malalignment and in turn unacceptable reduction. In one of the first series employing DCS, Sanders et al. [7] in 1989 reported excellent-good results in 71% and excellent-fair outcomes in 83% cases of distal femur fractures managed with DCS. They also described ease of insertion, ability to achieve good purchase even in osteoporotic bone, potential to obtain interfragmentary compression, and the flexibility of revising non-unions with a simple plate exchange are recognizable benefits of the DCS over the 95* ABP. Since then, several authors have reported good outcomes in supracondylar distal femur fractures using DCS [8]. Schatzker et al. [9] in a prospective series studying the results of DCS concluded that though DCS is nearly similar compared to ABP, several technical drawbacks are associated with the ABP use. These pitfalls include: (i) chances of fracture displacement, which has been previously reduced, while hammering in the CBP in case the bone is very hard, (ii) the bone may explode as the seating chisel is driven in because of the stresses it generates, (iii) difficulty to hammer in the chisel corresponding to the guide wire, particularly if the bone offers

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resistance, and (iv) malalignment of sitting chisel in the sagittal plane if its guide wire is not kept in line with the femoral shaft axis. With a very narrow margin for error, ABP being a monoblock device requires reinsertion of the seating chisel to correct even minimal mal-reduction, a task technically challenging. However, DCS itself is associated with multiple flaws: (i) bulky size of implant, which frequently requires substantial bone removal from lateral femoral condyle, (ii) irritation of iliotibial band (ITB), (iii) limited sizes of barrel plates predisposing to periprosthetic fractures, (iv) need for extensive surgical exposure leading to compromised local vascular supply, (v) inability to fix comminuted intra-articular fractures (AO/OTA 33-C3), (vi) conferring absolute stability instead of relative stability, and vii) non-locking nature resulting in frequent varus collapse compelled the need for a better implant design.

Distal Femur Locking Plate Although results with these non-locking fixed angled devices were an upgrade over non-operative management, they were still being used with the goal of absolute stability and primary bone healing and called for an invasive surgical approach. At this time, patients’ outcomes were still afflicted with local complications (including but not limited to non-union/delayed union, infection and implant failure) and less than optimal functional outcome despite “successful” surgery [10–12]. In 1989, Mast et al. first described the significance of minimizing soft tissue dissection and surgical handling of the fracture site to obtain fracture reduction. They called it “indirect reduction” of the fracture. This maintains vascularity of the fracture margins and thus decreases the chances of non-union [13]. Subsequently Krettek et al. [14–16], building on this concept, emphasized that attaining relative stability at the fracture fairs over absolute stability. They also advised minimal disruption of the fracture site, which can be achieved by submuscular plate “dragging” alongside the femur shaft, namely: Minimally Invasive Percutaneous Plate Osteosynthesis (MIPPO) [17]. In a cadaveric study model, Zlowodski et al. [18] showed that perforating blood vessels were preserved when plate was passed submuscularly beneath the vastus lateralis muscle. Compared to the traditional lateral approach, which involves elevation of vastus lateralis and dubious damage to the perforating vessels, MIPPO preserves periosteal as well as medullary perfusion additionally. This led to the development of anatomical periarticular locking plates in the late 1990s. Unlike classical plates, locking plates do not depend on friction at the bone–plate interface to achieve stability. Screws are fixed to the plate by certain locking mechanisms between the screw hole and head to allow them to be placed at a certain prefixed angle. Hence, locking plates are not in direct contact with the bone, which helps preserve periosteal vascular supply. Each locking screw acts as a fixedangle device augmenting the stability of the entire construct as the plate is secured to the bone at multiple points and this negates movement at plate–bone surface. These implants commonly employ MIPO techniques, locked screws that offer stable fixedangle purchase in distal articular fragment and the concept of “bridging” to address

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metaphyseal comminution. In cases with long oblique fractures fixed using lag screws, these plates also provide stability employing principles of “neutralization plating”. Locking plates can be used to stabilize both intra-articular as well as extraarticular distal femur fractures applied with or without MIPO technique that protects fracture biology [19]. Refined understanding of the fracture biology, importance of preserving an intact soft tissue envelope, and the introduction of anatomical locking plates led to the inception of biologically attached plate osteosynthesis of supracondylar distal femoral fractures by Less Invasive Stabilization System (LISS) (Synthes) (Fig. 2). The LISS acts as an internal fixator and employs the principle of “bridge-plating”. This technique was patented in 1990 and the first implantation of LISS was made in 1995. This advancement over standard available locking plates reduced the need for primary bone grafting [20, 21]. LISS was designed as an upgrade to MIPO technique that allowed for direct reduction of articular fragments and fixation using locked screws combined with indirect reduction of metaphyseal fracture site and percutaneous screw insertion for fixation of the shaft. Early results were quite promising, with union rate of more than 90% while avoiding primary bone grafting [21]. With minimally invasive techniques gaining popularity, the distal femur locking plates (DFLP) virtually replaced ABP and DCS for management of nearly all distal femoral fractures. Several authors reported successful management of nearly most distal femoral fractures using these locking plates and LISS technique [22–24]. Zlowodzki et al. [18] conducted a systemic review and reported that average rates of non-union, deep infection, fixation failure, and secondary surgery approached 5.5%, 2.1%, 4.9%, and 16.2%, respectively. Technical errors contributing to fixation

Fig. 2 (a) Less Invasive Stabilization System (LISS), (b) Jig along with various sleeve attachment

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failure included prolonged time interval for secondary bone grafting, early weight-bearing, and anterior placement of the plate over the femur shaft. Despite these pitfalls, a union rate of 100% and 88% excellent clinical outcome was achieved with LISS, as reported in several studies [23, 25]. The advantages of DFLP over earlier implants include: (i) minimal disruption of local vascular supply, (ii) better purchase in osteoporotic bone, (iii) imparting relative fracture stability, (iv) anatomical design, which allows it to be used as a “reduction mold”, directing the bone to the plate, (v) versatility in plate lengths, (vii) technically less demanding, and (vii) ability to fix complex intra-articular fractures including AO 33 C-3 type patterns. Distal femoral locked plates were also found to be biomechanically stable compared to the earlier non-locking devices. Higgins et al. [26] in a biomechanical study in cadavers with simulated AO 33 A-3 fractures concluded that the DFLP construct fared better compared to the angled blade plate with regard to both ultimate strength as well as cyclical loading. Despite numerous advantages over older fixed-angle constructs, the traditional DFLP did not live up to the definition of a “perfect implant”. The pitfalls with this DFLP were: (i) inability to fix complex intra-articular comminuted fractures and periprosthetic fractures due to fixed screw configuration, (ii) too rigid construct owing to locked screws in the proximal fragment, and (iii) high implant stiffness compared to parent bone.

Modern Locking Plates Despite remarkable improvement in the clinical results, high incidence of delayed union, non-union, and implant failure continued to plague traditional locking plates [27, 28]. Operative techniques significantly influence union and failure rates, necessitating the search for optimal techniques. Promoting micromotion between the fracture fragments by altering the stiffness of the construct encourages callous formation and thus union [29, 30]. Modern locking plates comprise several modifications that affect construct stiffness including plate length, material, screw type and density, and working length to improve bone healing.

Distal Femoral Locking Compression Plate (DFLCP) The need to achieve compression between the fracture fragments led to the development of distal femur locking compression plate (DFLCP) that allows for application of both locking as well as cortical screws in the same plate [31] (Fig. 3). This “hybrid”-fixation technique wherein cortical screws permit interfragmentary compression and locking screws offer increased pull-out strength especially in osteopenic bones has been demonstrated to be comparable to all-locking screw construct in biomechanical studies too. In an osteoporotic simple shaft humerus synthetic fracture model, Gardner et al. [32] showed that both locked plate and hybrid construct had comparable strength in torsional stiffness and cyclic loading in

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Fig. 3 (a) AO-Depuy Synthes distal femur LCP, (b) Zimmer distal femur LCP

torsion. Freeman et al. [33] compared the biomechanical properties of diaphyseal locking and cortical screws in an osteoporotic and a non-osteoporotic cadaveric supracondylar femur fracture model and reported that locking screws offered biomechanical advantage only in osteoporotic model. In contrast to DCS, fixation of the distal femoral fractures using DFLCP resulted in biomechanically superior construct in both ultimate strength and cyclic loading [34]. In another biomechanical study, Stoffel et al. [35] compared LCP with compression plate(CP) and locking plate(LP). In comminuted fractures, when tested under compression LP offered comparable fixation to CP while avoiding loss of reduction, whereas under torsional loading CP fared over LP in terms of stiffness, load to failure, and plastic deformation. Hence, they concluded that a combination (LCP) fixation seems prudent to address both intra-articular and extra-articular fractures with metaphyseal comminution.

Variable Angle Locked Compression Plate (VA-LCP) Fixed geometry of distal locking screws resulting in compromised fixation in fractures with severe articular comminution or patients with altered anatomy led to development of variable angle-locked compression plates (VA-LCP) (Fig. 4). Standard DFLCP offers unidirectional locking screws that employ a locking mechanism between the screw head and the plate to create a fixed angle construct, whereas variable angle locking plates offers multidirectional screw placement within certain

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Fig. 4 (a) Depuy Synthes 4.5 mm Variable-Angle LCP, (b) Zimmer Non-Contact Bridging (NCB) Distal femur Variable Angle plate, (c) NCB plate with Screw and locking mechanism, (d) Variable screw arrangement in Conventional vs Variable Angle LCP

limit (as much as 30* cone of variability) based on the applied locking mechanism. These polyaxial plating systems allow for selective placement of the locking screws that provides flexibility to capture, reduce, and stabilize complex fracture patterns and integrate to form a fixed-angle distal articular block. However, these implants typically cost higher compared to the traditional plates. A biomechanical study, Kenneth et al. [36] concluded that compared to uniaxial locking plates, VA-LCP construct is biomechanically stable in terms of ultimate load to failure, mean axial, and torsional stiffness for fixation of supracondylar femoral fractures. Similarly, Wilkens et al. [36] reported that variable angle screws provide increased strength under axial compression and torsion and reduces deformation under cyclic loading. Campana et al. [37] in a retrospective series of 42 patients managed with VA-LCP reported good clinical outcome and bone union compared to other standard distal femoral locking plates without any early mechanical failures. They also concluded that VA technology offers greater versatility for internal fixation of fractures and can also accommodate previously placed implants or prosthesis, as in periprosthetic fractures. McDonald et al. [38] in a retrospective series of 113 patients, managed with AO VA-LCP, deduced that VA-LCP is a lucrative option for distal femoral fractures with an admissible failure rate. Implant failure and reoperation rate approached 9.3% and 16.9%, respectively, while open fractures, presence of medial metaphyseal comminution, the length of comminution, and plate length correlated with higher implant failure rate. Tank et al. [39] evaluated the clinical outcomes in 67 patients managed with LISS plates, uniaxial DFLCP, and VA-LCP. They documented higher early biomechanical failure with VA-LCP in AO 33-C fractures compared to standard locking plates and also cautioned practicing surgeons against VA-LCP use for fixation of comminuted metaphyseal distal femoral fractures.

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Plate Length and Screw Density Plate length also plays a crucial role in union of distal femoral fractures. Longer plates with lower screw density decrease the construct rigidity. A plate length of 9 hole or more was found to be associated with decreased revision surgery rates by Ricci et al. [27]. Failure rate was 14% with eight-holed plates or less compared to 3% with nine or more hole plates. Apart from plate length, screw number also plays a salient role in regulating construct stiffness. Higher screw density in the proximal diaphyseal fragment decreases micromotion across the fracture site resulting in less callus formation [40, 41], especially true if majority of proximal screws are locking [42]. Hence, cortical screws or a combination of locking and non-locking screws (“hybrid fixation”) is preferred. Various authors have also recommended using half the available screws to fix the diaphyseal fragment and securing no more than eight cortical purchase to optimize construct stiffness [29]. In addition, the distal most screw in the proximal fragment independently affects plate rigidity [44] as it determines the working length of the construct [43]. The working length and thereby the micromotion necessary for fracture healing can be controlled by the surgeon by altering screw placement within the plate. Working length is inversely proportional to the construct stiffness and promotes interfragmentary motion, especially needed for healing of metaphyseal comminution. In a biomechanical study employing locked plates, Mardian et al. [43] demonstrated that when locking screws are used in the diaphyseal femur, fragment axial motion is higher on the medial side compared to the lateral side. Stiffer lateral side leads to imbalanced forces across the fracture site consequently affecting new bone formation, especially given the propensity for varus collapse in distal femur fractures that fail to heal [44]. Despite being in practice for several decades, the perfect plate/ working length for distal femur fractures remains elusive and determining this will help in better management of these fractures while avoiding complications (Fig. 5).

Far Cortical Locking Screws Despite best application of lateral DFLCP with preservation of micromotion, asymmetric callus generation is observed across the fracture site [44]. Proximity to the plate decreases micromotion at the lateral cortex. Concept of far cortical locking (FCL) is introduced to address this asymmetrical motion at the “stiffer” lateral cortex consistent with use of lateral DFLCP. FCL can be achieved either with specifically designed screws or by over-drilling the lateral cortex. In this way, the micromotion is preserved at the near cortex as the screw gains fixation only in the plate and the far medial cortex. This method promotes symmetric motion at both the medial and lateral aspects of the fracture site necessary for bone healing while providing comparable strength to standard locking and bicortical screw fixation [45]. Axial stiffness is reduced to one-fifth with the use of FCL screws while maintaining strength to failure and resistance to torsional and bending forces [30]. Biomechanical analysis by Doornink et al. [46] demonstrated 500% increased micromotion between the fracture fragments with properly applied FCL screws compared to standard

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Fig. 5 One year post-op radiograph depicting successful union of distal femur fracture. Note ideal screw and plate configuration: (i) Distal screw parallel to the knee joint line, (ii) nine hole plate, (iii) Distal extent of plate up to Blumensaat line, (iv) Sparsely placed proximal screws with eight cortical purchase

locking constructs. Also, it promotes symmetric motion at both medial as well as lateral femoral cortex theoretically minimizing the chances of asymmetric callus formation and thus probable non-union. In 2015, Adams et al. [47] examined the clinical effects with FCL screw use in 15 distal femur fractures. With no non-unions or implant failures and 24 weeks as average time to union, they opined that FCL screws may offer a lucrative option to avoid high non-union rate in comminuted distal femoral fractures fixed with traditional locked plates. Bottlang et al. [48] in a prospective observational series comprising 33 patients managed with FCL-plateconstructs documented successful healing in a mean time of 15.6 weeks with no evidence of implant failure. Building on this idea, Galal et al. [49] reported 100% union rate within a mean duration of 13.4 weeks in 20 patients with distal femoral fractures managed by “Dynamic” locked plating employing the near-cortex-overdrilling technique. A retrospective comparative study between FCL construct and traditional LP construct by Plumarom et al. revealed that the FCL group had significantly increased callus formation at all follow-up periods albeit insignificant differences in healing or complication rates between the two groups.

New Implant Materials Newer implant materials have paved the way for surgeons to improve the clinicradiological outcomes for distal femoral fractures. Compared to stainless steel alloys, titanium offers modulus of elasticity closer to bone and hence results in uniform

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Fig. 6 Carbon fibre reinforced-PEEK plate (Courtesy: Invibio Biomaterial Solutions)

callus formation [44]. In a series of 271 distal femoral fractures, Rodriguez et al. [50] reported that non-union rate was one-fourth with the use of titanium plates compared to stainless steel lateral LP. Recent advancements in the field of material sciences involve innovations in carbon fibre technology. Modulus of elasticity for carbon fibre plate (Fig. 6) is ten times close to the bone [51]. Mitchell et al. in a retrospective case series [52] involving 22 patients reported promising short-term results with carbon fibre reinforced–PEEK plate compared to plates made up of stainless steel, although the differences were minimal, necessitating the need for future studies with more sample size and study duration.

New Plate Designs Construct stiffness is pivotal to fracture healing stabilized using locked plates. In order to find the optimal implant, Schmidt et al. [53] compared four plate systems with different implant materials and designs in a distal femur fracture model (6 specimens each). Investigated systems include: (i) AxSOS (Stryker, Selzach, Switzerland), (ii) LCP (Synthes, Switzerland), (iii) PERI-LOC (Smith & Nephew, Memphis, TN, USA) (Fig. 7), and (iv) POLYAX system (DePuy, UK). Results

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Fig. 7 (a) Smith and Nephew Peri-Loc Distal Femur plate. The unique plate design allows for insertion of screws apart from the plate. This provides customized screw configurations to optimally treat each specific fracture

depicted that AxSOS ranked best for mean construct stiffness under axial loading (100.8 N/mm) followed by PERI-LOC (80.8 N/mm), LCP (62.6 N/mm), and POLYAX (51.7 N/mm) with half the stiffness of AxSOS. Under torsional loading, mean construct stiffness was comparable in the group of AxSOS and PERI-LOC (3.40 Nm/degree vs. 3.15 Nm/degree) and in the group of LCP and POLYAX (2.63 Nm/degree vs. 2.56 Nm/degree). The fourth load level of >75,000 cycles was reached by three of six AxSOS, three of six POLYAX, and two of six PERILOC constructs. All others including all LCP constructs failed prematurely. The authors concluded that plate material and design of these newer implants significantly affect construct stiffness and in turn bone healing. Micromotion at fracture site promotes callus formation essential to fracture healing; consistent with this school of thought, biomedical engineers from the AO Research Institute Davos (ARI), in concert with Queensland University of Technology (QUT), developed the “biphasic anatomical distal femur plate”. Due to its special design, it allows for the motion necessary for fracture union while avoiding overloading, contrary to the conventional plates. Additionally, the biphasic plate standardizes surgical procedures and is surgeon-friendly. Unfortunately, these plates are still experimental and unavailable in the market for clinical use.

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Dual Plating Despite remarkable advancements in the periarticular LCP designs, lateral locked plates alone are unable to provide the required biomechanical stability to various complex distal femur fracture patterns eventually resulting in non-union. Usually a result of high energy trauma in young patients, these fractures involve substantial metaphyseal comminution, extension into articular surface, and significant soft tissue injury. In cases with complex intra-articular fracture fragments fixed with individual screws, lateral DFLCP may not provide the desired stability as the fixed angled screws hinder with this preexisting hardware precluding their placement. Furthermore, in fractures with severe metaphyseal comminution, single lateral plate may result in an unstable construct due to increased gap at fracture site. In older individuals, although the fracture pattern is usually simple the complementary osteopenia results in inadequate bony purchase despite usage of locking screws. Peschiera et al. [54] reported that medial cortical bone defect, primary malreduction, severe axial bone gap, and unbalanced fixation are foremost predictors for nonunion. Both fracture biology as well as mechanics need to be addressed for successful management of such non-unions. With increasing complications following lateral plating alone and ever-rising severity of fracture patterns, an optimal solution was needed to increase the distal femur construct stiffness while respecting the fracture biology. Hence, dual plating for distal femur fractures, which comprises a lateral and a supplementary medial plate, was developed for improved radiological and functional outcomes (Fig. 8). The indications of dual plating [55] include: (i) medial supracondylar bone loss, (ii) low trans-condylar bicondylar fractures, (iii) medial Hoffa fracture, (iv) periprosthetic distal femur fractures, (v) non-union after failed fixation with single lateral plate, (vi) severe osteoporosis, and (vii) comminuted fractures (AO type C-3). Briffa et al. [56] compared medial vs lateral locked plating in unstable supracondylar femur fracture model. The authors reported that medial plating alone fared better than lateral plating in terms of fracture displacement and bending moment and strain at the fracture site in axial loading. Comparing single vs dual plating, studies have concluded that dual plating confers notably increased biomechanical stability in comminuted distal femur fractures [57–59]. Bai et al. [60] in a comparative study reported that mean surgical duration, intraoperative blood loss, time to bone union, and postoperative functional outcome are similar for both dual as well as single plating. Authors also proposed that a positive intraoperative varus stress test (after excluding lateral collateral ligament rupture) can be an indication for addition of medial plate in distal femur fractures. Sun et al. [61], in a series comprising 32 comminuted distal femur fractures, reported that medial plating in addition to a lateral plate increases the fracture stability and improves the healing rate. Distal femur non-union following fixation with lateral plate alone is associated with chronic pain, axial malalignment, loss of ambulation, and decreased knee ROM. Holzman et al. [62] reported successful radiographic union in 20 of the 21 non-unions within 12 months following addition of the medial

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Fig. 8 (a) Pre-op radiograph of 32 year male showing AO/OTA C3 fracture, (b, c) 3D CT-Scan depicting severe comminution, (d) Post-op radiograph demonstrating unacceptable varus collapse due to lack of adequate biomechanical stability, (e) Post-revision radiograph. ORIF with additional medial plate and synthetic bone graft done

plating. Rajasekaran et al. [63] after analysing 62 cases, devised an algorithmic approach to management of recalcitrant distal femoral non-unions. They suggested that after ensuring stable fixation and good alignment if there is no medial void, mere bone grafting is sufficient. But auxiliary structural medial metaphyseal allograft/ autograft is required if the medial void is 2 cm benefit from addition of medial plating. In order to minimize medial soft tissue stripping and iatrogenic injury to vascular structures during medial dissection, Ziran et al. [64] proposed orthogonal dual plating (anterior + lateral) using anterior approach. Authors reported successful healing in 72.7% patients using this technique.

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Intramedullary Nailing Minimally invasive implants and percutaneous reduction techniques have allowed for preservation of soft tissue envelope, decreased operative time, and blood loss while providing stable fixation. Retrograde distal femur intramedullary nail (Fig. 9) approximates the force vector of the femur and is recommended by the AO/ASIF group for closed management of supracondylar femur fractures. Insertion of retrograde intramedullary nail (RIMN) minimizes soft tissue trauma while preserving the blood supply and also facilitates early rehabilitation. Dwelling on this concept, retrograde intramedullary nailing (RIMN) is being increasingly adopted for management of distal femoral fractures. Indications of RIMN include AO/OTA type A, C1, and C2 fractures (Fig. 10). RIMN provides stable fixation along with adequate

Fig. 9 (a) Pre-op radiograph showing AO/OTA A1 distal femur fracture, (b) 1 year postoperative X-ray demonstrating successful union managed with Retrograde Intramedullary Nailing (RIMN)

Fig. 10 (a) Pre-op radiograph showing AO/OTA C2 fracture of distal femur, conventionally managed by ORIF with plating (b) Post-op X-ray. Articular reduction achieved with indirect reduction and percutaneous CCS fixation followed by RIMN

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micromotion between the fracture fragments and allows for early weight-bearing [65]. Compared to plating, RIMN is associated with more uniform callus formation [28, 44]. Although healing rates are similar to plating, RIMN provides higher patient satisfaction probably because of the minimally invasive approach and early mobilization [22]. Hence, RIMN can provide a rewarding fixation modality with comparable healing, if patients are selected judiciously [22, 40]. In a systemic review by Zlowodzki et al. [18] assessing the outcomes following RIMN in distal femur fractures, the complication rates included: non-union (5.3%), fixation failure (3.2%), infection (0.4%), and re-surgery (24.2%). Open fractures preclude usage of plating and impose a treatment dilemma, but RIMN has reported to provide stable fixation with early knee ROM without any increased incidence of septic arthritis and secondary degenerative lesions [66]. Henry et al. [67] conducted a comparative study and explored the benefits of percutaneous reduction techniques in RIMN. Percutaneous approach lessens the surgical duration, intra-op blood loss, need for secondary bone grafting, and incidence of non-union while enhancing postoperative knee rehabilitation. On prospectively comparing RIMN with plating [68, 69], the reported union rate was similar in both the groups, 90% vs 84.6%, but RIMN fared over plating in terms of knee ROM, early bone healing, infection, and complication rates. Furthermore, Markmiller et al. [70] in a prospective study reported equivalent and satisfactory clinic-radiological results with LISS and RIMN. However, RIMN resulted in statistically lower intra-op haemorrhage, surgical time, and duration of hospital stay. A systemic review by Shah et al. [71] concluded similar rates of bone healing and union time between DFLCP and RIMN in management of periprosthetic distal femoral fractures. Complication and reoperation incidence was lower among those managed with plating whereas rehabilitation and return to activities of daily living was earlier with RIMN. Hierholzer et al. [72] in a retrospective analysis of 115 patients reported that both constructs offer equivalent outcomes for distal femur fractures if used judiciously. Detailed preoperative planning and proper application of orthopaedic principles reduce complication rates, and clinical results are largely determined by surgical technique rather than the implant choice. Complications pertaining to RIMN comprise: (i) injury to deep femoral artery during proximal locking, (ii) anterior knee pain, (iii) iatrogenic femoral shaft fracture, (iv) stress fracture above the level of nail, (v) fatigue failure of the nail, (vi) intra-articular impingement, and (vii) varus malalignment [18, 31, 66]. Also, RIMN is unsuitable for AO type C-3 fractures. Antegrade IM nailing is suitable only for AO type A supracondylar femur fractures with distal fragment size >5 cm to allow for requisite distal fixation. Advantages of antegrade nails include (i) load sharing construct, (ii) minimal surgical manipulation of fracture site, and (iii) evading knee arthrotomy [11]. Zlowodzki et al. [18] in a systemic review on antegrade nailing for distal femur fracture reported good clinical outcomes with a cumulative incidence of 8.3%, 3.7%, 0.9%, and 23.1% for non-union, construct failure, infection, and reoperation, respectively.

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Nail + Plate Construct Rise in fracture incidence and severity led to increased use of dual plating. Also use of either RIMN or lateral plating is increasing with growing numbers of periprosthetic fractures. Lateral plating and RIMN constitute two established treatment modalities in fixation of periprosthetic distal femur fractures, but no consensus exists regarding superiority of any single method. As an addition to lateral plating, Chen et al. [73] used an intramedullary allograft strut in an osteoporotic fracture model and concluded that combination construct is more stable compared to lateral plate alone. High failure rates especially in osteoporotic bones necessitated the need for auxiliary fixation complementary to lateral plating and led to the development of nail-plate construct (NPC). Apprehension regarding construct stability following fixation with a single implant often leads to protracted weight-bearing, especially in osteopenic bones [74–76]. The goal is to achieve even distribution of forces among bone and implants while promoting early weight-bearing. While intramedullary nails act as a load sharing device and allows micromotion between fracture fragments, lateral plates are load bearing and allows more rigid fixation with stress shielding of medial cortex. Liporace et al. [77] hypothesized that placing an intramedullary nail moves the weight-bearing axis of the femur more medial to match the anatomic axis of the femur. The adjuvant lateral plate provides additional stability while decreasing motion between the fracture fragments. Combining these two fixation modalities while spanning the entire femur potentially provides a well-balanced, stronger fixation construct to provide confident, early weight-bearing following surgery (Fig. 11).

Fig. 11 (a) Pre-op radiograph of 25-year-old male with distal femoral non-union leading to implant failure, (b) Post-op radiograph. Patient managed with implant removal and ORIF with Zimmer VA-NCB application. RIMN was additionally added to act as an intramedullary strut and supplement stability

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Basci et al. [78] compared NPC with lateral plating and RIMN for their biomechanical stability. NPC yielded significantly more resistance compared to both in axial, torsional load testing and load to failure tests. Liporace et al. [77] managed 15 septuagenarian patients(nine peri-prosthetic + six native distal femur fractures) with nail and plate combination technique. One patient died in the follow-up period due to an unrelated cause, but in the remaining 14 patients, successful healing and satisfactory ambulatory status was achieved. In a retrospective series Attum et al. [79] observed 100% bone healing in all ten patients managed with a NPC and autogenous bone grating for non-union of distal femur fractures.

Distal Femoral Replacement (DFR) Significant intra-articular comminution, osteoporosis, unstable total knee arthroplasty (TKA) in situ, and ipsilateral knee osteoarthritis pose significant limitations to ORIF with plating or RIMN. DFR is an effective and upcoming surgical option, preferred by reconstructive surgeons. DFR comprises resection of the entire distal femur fracture fragment and substitution with a hinged knee prosthesis. DFR offers a worthwhile management strategy, although suitable for a specific subset of patients. Unfortunately, data regarding the exact indications and clinical outcomes following the procedure is limited at present. However, DFR constitutes a rewarding option in low-demand osteoporotic elderly with either/combination of the following: severe intra-articular comminution and associated osteoarthritis. The primary aim of DFR is to achieve pre-injury activity status as soon as possible while eliminating the fracture. Non-union rate approaches 18% in patients older than 70 years and comminuted fracture patterns managed with internal fixation [80]. Moreover, early resumption of weight-bearing in elderly individuals following osteosynthesis significantly influences duration of hospitalization and risk of complications like: venous thrombosis, pneumonia, pressure sores, joint stiffness, and urinary tract infections [81]. Compared to osteosynthesis, DFR has equivalent complication rate when used for management of either periprosthetic or naïve complex fractures [82–84]. Also, DFR leads to early return to preoperative ambulatory status compared to matched patients managed with plating. Although DFR seems to fare over ORIF in terms of postoperative outcomes, data regarding comparative intraoperative variables including blood loss and surgical duration is scarce. The current literature also reports similar 1-year mortality between DFR and osteosynthesis [40, 80]. For most patients, DFR will last for their remaining life span and provide them with better functional results compared to those undergoing ORIF. Although there is enough data to suggest that DFR is a viable modality for most judiciously selected patients, most of it is retrospective in nature. Few limitations that fetter this option include: (i) limited clinical experience, (ii) higher cost of implant; however, it is compensated by the decreased complication rate and shorter duration of hospitalization [83], (iii) time lapse to surgical intervention compared with ORIF. This likely results from finding an experienced and trained surgeon and the lead time necessary to procure

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the desired implants [64]. Despite these impediments, the advantages of DFR make it a valuable research topic for further exploration, especially with the rising proportion of elderly population, who requires this type of treatment.

Conclusion The treatment of distal femoral fractures improved ever since the 1970s, when operative intervention became the choice of management for such injuries. However, successful healing in distal femoral fractures is multifaceted. Fracture pattern, patient’s bone quality, and biomechanical properties of the fixation construct chiefly influence choice of optimal treatment protocol. Fixed angled devices, introduced among the first implants for management of these injuries, were quickly replaced by periarticular locking plates. Although these plates quickly gained popularity, the complications associated with construct stiffness forced the clinicians to search for better implants and techniques. Holistic understanding of the factors that affect stiffness of the construct and fracture biology paved way for improvements in the implant design and the clinical outcomes henceforth. These determinants include, but are not limited to, implant material, screw density, plate length, plate design, far cortical locking, and dual implants. Retrograde nailing is a treatment modality with some potential advantages over plate osteosynthesis and has shown promising results in several studies, in carefully selected patient population. DFR is an upcoming treatment method for managing distal femur fractures but warrants further exploration. The optimal implant choice for the management of distal femoral fractures still remains elusive and requires contemplation of both patient- and surgeon-related factors. Further research with larger cohort and study duration evaluating these techniques/implants will help improve the clinical outcomes.

References 1. Martinet O, Cordey J, Harder Y, Maier A, Bühler M, Barraud GE. The epidemiology of fractures of the distal femur. Injury. 2000;31:62–94. 2. Della Rocca GJ, Leung KS, Pape H-C. Periprosthetic fractures: epidemiology and future projections. J Orthop Trauma. 2011;25:S66–70. 3. Gates DJ, Alms M, Cruz MM. Hinged cast and roller traction for fractured femur. A system of treatment for the Third World. J Bone Joint Surg Br. 1985;67(5):750–6. 4. Butt MS, Krikler SJ, Ali MS. Displaced fractures of the distal femur in elderly patients: operative versus non-operative treatment. J Bone Joint Surg Br. 1996;78(1):110–4. 5. Moore TJ, Watson T, Green SA, Garland DE, Chandler RW. Complications of surgically treated supracondylar fractures of the femur. J Trauma. 1987;27(4):402–6. 6. Ricci WM. Periprosthetic femur fractures. J Orthop Trauma. 2015;29(3):130–7. 7. Sanders R, Regazzoni P, Ruedi TP. Treatment of supracondylar-intracondylar fractures of the femur using the dynamic condylar screw. J Orthop Trauma. 1989;3(3):214–22. 8. Ostrum RF, Geel C. Indirect reduction and internal fixation of supracondylar femur fractures without bone graft. J Orthop Trauma. 1995;9(4):278–84.

83

Implantology of Fractures of the Distal Femur

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9. Schatzker J, Mahomed N, Schiffman K, Kellam J. Dynamic condylar screw: a new device. A preliminary report. J Orthop Trauma. 1989;3(2):124–32. 10. Giles JB, DeLee JC, Heckman JD, Keever JE. Supracondylar-intercondylar fractures of the femur treated with a supracondylar plate and lag screw. J Bone Joint Surg Am. 1982;64(6): 864–70. 11. Schatzker J, Horne G, Waddell J. The Toronto experience with the supracondylar fracture of the femur, 1966–1972. Injury. 1974;6(2):113–28. 12. Siliski JM, Mahring M, Hofer HP. Supracondylar-intercondylar fractures of the femur. Treatment by internal fixation. J Bone Joint Surg Am. 1989;71(1):95–104. 13. Mast J, Jakob R, Ganz R. Reduction with plates. In: Planning and Reduction Technique in Fracture Surgery. Springer; 1989. p. 48–129. 14. Krettek C, Schandelmaier P, Miclau T, Bertram R, Holmes W, Tscherne H. Transarticular joint reconstruction and indirect plate osteosynthesis for complex distal supracondylar femoral fractures. Injury. 1997;28:A31–41. 15. Krettek C, Schandelmaier P, Nliclau T, Tscherne H. Minimally invasive percutaneous plate osteosynthesis (MIPPO) using the DCS in proximal and distal femoral fractures. Injury. 1997;28:A20–30. 16. Farouk O, Krettek C, Miclau T, Schandelmaier P, Guy P, Tscherne H. Minimally invasive plate osteosynthesis: does percutaneous plating disrupt femoral blood supply less than the traditional technique? J Orthop Trauma. 1999;13(6):401–6. 17. Krettek C, Müller M, Miclau T. Evolution of minimally invasive plate osteosynthesis (MIPO) in the femur. Injury. 2001;32:14–23. 18. Zlowodzki M, Bhandari M, Marek DJ, Cole PA, Kregor PJ. Operative treatment of acute distal femur fractures: systematic review of 2 comparative studies and 45 case series (1989 to 2005). J Orthop Trauma. 2006;20(5):366–71. 19. Hake ME, Davis ME, Perdue AM, Goulet JA. Modern implant options for the treatment of distal femur fractures. JAAOS-J Am Acad Orthop Surg. 2019;27(19):e867–75. 20. Perren SM. Fracture healing. The evolution of our understanding. Acta Chir Orthop Traumatol Cechoslov. 2008;75(4):241–6. 21. Kregor PJ, Stannard JA, Zlowodzki M, Cole PA. Treatment of distal femur fractures using the less invasive stabilization system: surgical experience and early clinical results in 103 fractures. J Orthop Trauma. 2004;18(8):509–20. 22. Hoskins W, Sheehy R, Edwards ER, Hau RC, Bucknill A, Parsons N, et al. Nails or plates for fracture of the distal femur? Data from the Victoria Orthopaedic Trauma Outcomes Registry. Bone Joint J. 2016;98(6):846–50. 23. Schütz M, Müller M, Regazzoni P, Höntzsch D, Krettek C, Van der Werken C, et al. Use of the less invasive stabilization system (LISS) in patients with distal femoral (AO33) fractures: a prospective multicenter study. Arch Orthop Trauma Surg. 2005;125(2):102–8. 24. Weight M, Collinge C. Early results of the less invasive stabilization system for mechanically unstable fractures of the distal femur (AO/OTA types A2, A3, C2, and C3). J Orthop Trauma. 2004;18(8):503–8. 25. Schandelmaier P, Partenheimer A, Koenemann B, Grün OA, Krettek C. Distal femoral fractures and LISS stabilization. Injury. 2001;32:55–63. 26. Higgins TF, Pittman G, Hines J, Bachus KN. Biomechanical analysis of distal femur fracture fixation: fixed-angle screw-plate construct versus condylar blade plate. J Orthop Trauma. 2007;21(1):43–6. 27. Ricci WM, Streubel PN, Morshed S, Collinge CA, Nork SE, Gardner MJ. Risk factors for failure of locked plate fixation of distal femur fractures: an analysis of 335 cases. J Orthop Trauma. 2014;28(2):83–9. 28. Henderson CE, Lujan T, Bottlang M, Fitzpatrick DC, Madey SM, Marsh JL. Stabilization of distal femur fractures with intramedullary nails and locking plates: differences in callus formation. Iowa Orthop J. 2010;30:61. 29. Beltran MJ, Gary JL, Collinge CA. Management of distal femur fractures with modern plates and nails: state of the art. J Orthop Trauma. 2015;29(4):165–72.

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V. Trikha and A. Gupta

30. Bottlang M, Lesser M, Koerber J, Doornink J, von Rechenberg B, Augat P, et al. Far cortical locking can improve healing of fractures stabilized with locking plates. J Bone Joint Surg Am. 2010;92(7):1652. 31. Crist BD, Della Rocca GJ, Murtha YM. Treatment of acute distal femur fractures. Orthopedics. 2008;31(7). 32. Gardner MJ, Griffith MH, Demetrakopoulos D, Brophy RH, Grose A, Helfet DL, et al. Hybrid locked plating of osteoporotic fractures of the humerus. JBJS. 2006;88(9):1962–7. 33. Freeman AL, Tornetta P III, Schmidt A, Bechtold J, Ricci W, Fleming M. How much do locked screws add to the fixation of “hybrid” plate constructs in osteoporotic bone? J Orthop Trauma. 2010;24(3):163–9. 34. Singh AK, Rastogi A, Singh V. Biomechanical comparison of dynamic condylar screw and locking compression plate fixation in unstable distal femoral fractures: an in vitro study. Indian J Orthop. 2013;47(6):615. 35. Stoffel K, Lorenz K-U, Kuster MS. Biomechanical considerations in plate osteosynthesis: the effect of plate-to-bone compression with and without angular screw stability. J Orthop Trauma. 2007;21(6):362–8. 36. Wilkens KJ, Curtiss S, Lee MA. Polyaxial locking plate fixation in distal femur fractures: a biomechanical comparison. J Orthop Trauma. 2008;22(9):624–8. 37. Campana V, Ciolli G, Cazzato G, Giovannetti De Sanctis E, Vitiello C, Leone A, et al. Treatment of distal femur fractures with VA-LCP condylar plate: a single trauma centre experience. Injury. 2019;S0020138319306849. 38. McDonald TC, Lambert JJ, Hulick RM, Graves ML, Russell GV, Spitler CA, et al. Treatment of Distal Femur Fractures With the DePuy-Synthes Variable Angle Locking Compression Plate. J Orthop Trauma. 2019;33(9):432–7. 39. Tank JC, Schneider PS, Davis E, Galpin M, Prasarn ML, Choo AM, et al. Early mechanical failures of the synthes variable angle locking distal femur plate. J Orthop Trauma. 2016 Jan;30(1):e7–11. 40. Henderson CE, Kuhl LL, Fitzpatrick DC, Marsh JL. Locking plates for distal femur fractures: is there a problem with fracture healing? J Orthop Trauma. 2011;25:S8–S14. 41. Cui S, Bledsoe JG, Israel H, Watson JT, Cannada LK. Locked plating of comminuted distal femur fractures: does unlocked screw placement affect stability and failure? J Orthop Trauma. 2014;28(2):90–6. 42. Harvin WH, Oladeji LO, Della Rocca GJ, Murtha YM, Volgas DA, Stannard JP, et al. Working length and proximal screw constructs in plate osteosynthesis of distal femur fractures. Injury. 2017;48(11):2597–601. 43. Märdian S, Schaser K-D, Duda GN, Heyland M. Working length of locking plates determines interfragmentary movement in distal femur fractures under physiological loading. Clin Biomech. 2015;30(4):391–6. 44. Lujan TJ, Henderson CE, Madey SM, Fitzpatrick DC, Marsh JL, Bottlang M. Locked plating of distal femur fractures leads to inconsistent and asymmetric callus formation. J Orthop Trauma. 2010;24(3):156–62. 45. Heyland M, Duda GN, Haas NP, Trepczynski A, Döbele S, Höntzsch D, et al. Semi-rigid screws provide an auxiliary option to plate working length to control interfragmentary movement in locking plate fixation at the distal femur. Injury. 2015;46:S24–32. 46. Doornink J, Fitzpatrick DC, Madey SM, Bottlang M. Far cortical locking enables flexible fixation with periarticular locking plates. J Orthop Trauma. 2011;25(Suppl 1):S29. 47. Adams JD Jr, Tanner SL, Jeray KJ. Far cortical locking screws in distal femur fractures. Orthopedics. 2015;38(3):e153–6. 48. Bottlang M, Fitzpatrick DC, Sheerin D, Kubiak E, Gellman R, Zandschulp CV, et al. Dynamic fixation of distal femur fractures using far cortical locking screws: a prospective observational study. J Orthop Trauma. 2014;28(4):181–8. 49. Galal S. Dynamic locked plating for fixation of distal femur fractures using near-cortical overdrilling: preliminary results of a prospective observational study. J Clin Orthop Trauma. 2017;8(3):215–9.

83

Implantology of Fractures of the Distal Femur

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50. Rodriguez EK, Zurakowski D, Herder L, Hall A, Walley KC, Weaver MJ, et al. Mechanical construct characteristics predisposing to non-union after locked lateral plating of distal femur fractures. J Orthop Trauma. 2016;30(8):403–8. 51. Hak DJ, Mauffrey C, Seligson D, Lindeque B. Use of carbon-fiber-reinforced composite implants in orthopedic surgery. Orthopedics. 2014;37(12):825–30. 52. Mitchell PM, Lee AK, Collinge CA, Ziran BH, Hartley KG, Jahangir AA. Early comparative outcomes of carbon fiber–reinforced polymer plate in the fixation of distal femur fractures. J Orthop Trauma. 2018;32(8):386–90. 53. Schmidt U, Penzkofer R, Bachmaier S, Augat P. Implant material and design alter construct stiffness in distal femur locking plate fixation: a pilot study. Clin Orthop Relat Res. 2013;471(9):2808–14. 54. Peschiera V, Staletti L, Cavanna M, Saporito M, Berlusconi M. Predicting the failure in distal femur fractures. Injury. 2018;49:S2–7. 55. Sain A, Sharma V, Farooque K. Dual plating of the distal femur: indications and surgical techniques. Cureus. 2019;11(12):e6483. 56. Briffa N, Karthickeyan R, Jacob J, Khaleel A. Comminuted supracondylar femoral fractures: a biomechanical analysis comparing the stability of medial versus lateral plating in axial loading. Strategies Trauma Limb Reconstr. 2016;11(3):187–91. 57. Park K-H, Oh C-W, Park I-H, Kim J-W, Lee J-H, Kim H-J. Additional fixation of medial plate over the unstable lateral locked plating of distal femur fractures: a biomechanical study. Injury. 2019;50(10):1593–8. 58. Zhang W, Li J, Zhang H, Wang M, Li L, Zhou J, et al. Biomechanical assessment of single LISS versus double-plate osteosynthesis in the AO type 33-C2 fractures: a finite element analysis. Injury. 2018;49(12):2142–6. 59. Zhang J, Wei Y, Yin W, Shen Y, Cao S. Biomechanical and clinical comparison of single lateral plate and double plating of comminuted supracondylar femoral fractures. Acta Orthop Belg. 2018;84:141–8. 60. Bai Z, Gao S, Hu Z, Liang A. Comparison of clinical efficacy of lateral and lateral and medial double-plating fixation of distal femoral fractures. Sci Rep. 2018;8(1):1–9. 61. Sun R, Zhang Y, Yu Z. Clinical efficacy of augmented medial assisted plate for treating comminuted metaphyseal fracture of the distal femur. Int J Clin Exp Med. 2018;11(4):3859–65. 62. Holzman MA, Hanus BD, Munz JW, O’Connor DP, Brinker MR. Addition of a medial locking plate to an in situ lateral locking plate results in healing of distal femoral nonunions. Clin Orthop Relat Res. 2016;474(6):1498–505. 63. Rajasekaran RB, Jayaramaraju D, Palanisami DR, Agraharam D, Perumal R, Kamal A, et al. A surgical algorithm for the management of recalcitrant distal femur nonunions based on distal femoral bone stock, fracture alignment, medial void, and stability of fixation. Arch Orthop Trauma Surg. 2019;139(8):1057–68. 64. Ziran B, Rohde R, Wharton A. Lateral and anterior plating of intra-articular distal femoral fractures treated via an anterior approach. Int Orthop. 2002;26(6):370–3. 65. Pekmezci M, McDonald E, Buckley J, Kandemir U. Retrograde intramedullary nails with distal screws locked to the nail have higher fatigue strength than locking plates in the treatment of supracondylar femoral fractures: a cadaver-based laboratory investigation. Bone Joint J. 2014;96(1):114–21. 66. Cieślik P, Piekarczyk P, Marczyński W. Results of retrograde intramedullary nailing for distal femoral fractures–own experience. Orthop Traumatol Rehabil. 2007;9(6):612–7. 67. Henry SL. Supracondylar femur fractures treated percutaneously. Clin Orthop Relat Res. 2000;375:51–9. 68. Hartin NL, Harris I, Hazratwala K. RETROGRADE NAILING VERSUS FIXED-ANGLE BLADE PLATING FOR SUPRACONDYLAR FEMORAL FRACTURES: A RANDOMIZED CONTROLLED TRIAL. ANZ J Surg. 2006;76(5):290–4. 69. Wu C-C, Shih C-H. Treatment of femoral supracondylar unstable comminuted fractures. Arch Orthop Trauma Surg. 1992;111(4):232–6.

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70. Markmiller M, Konrad G, Südkamp N. Femur–LISS and distal femoral nail for fixation of distal femoral fractures: are there differences in outcome and complications? Clin Orthop Relat Res. 2004;426:252–7. 71. Shah JK, Szukics P, Gianakos AL, Liporace FA, Yoon RS. Equivalent union rates between intramedullary nail and locked plate fixation for distal femur periprosthetic fractures–a systematic review. Injury. 2020;51(4):1062–1068. 72. Hierholzer C, von Rüden C, Pötzel T, Woltmann A, Bühren V. Outcome analysis of retrograde nailing and less invasive stabilization system in distal femoral fractures: a retrospective analysis. Indian J Orthop. 2011;45(3):243–50. 73. Chen S-H, Chiang M-C, Hung C-H, Lin S-C, Chang H-W. Finite element comparison of retrograde intramedullary nailing and locking plate fixation with/without an intramedullary allograft for distal femur fracture following total knee arthroplasty. Knee. 2014;21(1):224–31. 74. Hoffmann MF, Jones CB, Sietsema DL, Koenig SJ, Tornetta P III. Outcome of periprosthetic distal femoral fractures following knee arthroplasty. Injury. 2012;43(7):1084–9. 75. Ricci WM, Loftus T, Cox C, Borrelli J. Locked plates combined with minimally invasive insertion technique for the treatment of periprosthetic supracondylar femur fractures above a total knee arthroplasty. J Orthop Trauma. 2006;20(3):190–6. 76. Han H-S, Oh K-W, Kang S-B. Retrograde intramedullary nailing for periprosthetic supracondylar fractures of the femur after total knee arthroplasty. Clin Orthop Surg. 2009;1(4):201–6. 77. Liporace FA, Yoon RS. Nail plate combination technique for native and periprosthetic distal femur fractures. J Orthop Trauma. 2019;33(2):e64–8. 78. Başcı O. Combination of anatomical locking plate and retrograde intramedullary nail in distal femoral fractures: comparison of mechanical stability. Jt Dis Relat Surg. 2015;26(1):21–6. 79. Attum B, Douleh D, Whiting PS, White-Dzuro GA, Dodd AC, Shen MS, et al. Outcomes of distal femur nonunions treated with a combined nail/plate construct and autogenous bone grafting. J Orthop Trauma. 2017;31(9):e301–4. 80. Hart GP, Kneisl JS, Springer BD, Patt JC, Karunakar MA. Open reduction vs distal femoral replacement arthroplasty for comminuted distal femur fractures in the patients 70 years and older. J Arthroplast. 2017;32(1):202–6. 81. Streubel PN, Ricci WM, Wong A, Gardner MJ. Mortality after distal femur fractures in elderly patients. Clin Orthop Relat Res. 2011;469(4):1188–96. 82. Appleton P, Moran M, Houshian S, Robinson CM. Distal femoral fractures treated by hinged total knee replacement in elderly patients. J Bone Joint Surg Br. 2006;88(8):1065–70. 83. Atrey A, Hussain N, Gosling O, Giannoudis P, Shepherd A, Young S, et al. A 3 year minimum follow up of Endoprosthetic replacement for distal femoral fractures—an alternative treatment option. J Orthop. 2017;14(1):216–22. 84. Jassim SS, McNamara I, Hopgood P. Distal femoral replacement in periprosthetic fracture around total knee arthroplasty. Injury. 2014;45(3):550–3.

Implantology of Fractures of the Proximal Tibia

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Historical Aspects and Evolution of the Treatment of Tibial Plateau Fractures . . . . . . . . . . . . . . Internal Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bone Grafts and Substitutes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evidence from Biomechanical Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Extra-articular Comminuted Proximal Tibial Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker I Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker II Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker III Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker IV Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker V Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schatzker VI Fracture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fundamental Principles of Fixation of Tibial Plateau Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Guiding Principles and Crucial Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Skeletal Traction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Fixator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Modalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cannulated Cancellous Screws (6.5 mm CCS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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K. Vishwanathan (*) Department of Orthopaedics, Parul Institute of Medical Sciences and Research, Parul University, Vadodara, India S. Ghosh Woodlands Multispeciality Hospital Limited, Kolkata, India © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_82

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L Buttress Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T Buttress Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Types of T Buttress Plates (Fig. 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . One-Third Tubular Plate and Reconstruction Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lateral Tibial Head Buttress Plate 6.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP – Proximal Lateral Tibial Plate 5.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP – Lateral Proximal Tibial Plate 4.5 (Raft Plate 4.5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP – Lateral Proximal Tibial Plate 3.5 (Raft Plate 3.5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP – Medial Proximal Tibial Plate 4.5/5.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP – Medial Proximal Tibial Plate 3.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LCP Posteromedial Tibia Plate 3.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Variable Angle LCP Proximal Tibial Plate 3.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rim Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Tibial plateau fractures are major injuries around the knee joint. The historical aspects of the evolution of various methods of surgically treating extra-articular and intra-articular fractures of the proximal tibia have been described in the present chapter. The biomechanical rationale for the choice of various implants has also been discussed. An overview has been provided about various implants that are available to the present-day surgeon for effectively managing tibial plateau fractures. The current preference for Schatzker I to IV is to place 3.5 mm anatomical plates and screws on the lateral and the medial tibial plateau

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compared to the 4.5 mm plates and screws because the 3.5 mm plates are more malleable, less bulky, have better anatomical fit, and give the option to place more number of screws in the subchondral bone. Placement of smaller diameter screws proximally is biomechanically superior to placing fewer larger diameter screws. Schatzker V and VI fractures are highly unstable and the implants used must be effective against various deforming forces. If single-column fixation is deemed sufficient then a single laterally placed 4.5/5.0 anatomical locking plate is the preferred choice. If dual plating is contemplated, a 3.5 mm locking plate on the lateral side and medial sides are preferred. Keywords

Knee fractures · Tibial plateau fractures · Tibial fractures · Internal fixators · Internal fracture fixation · Bone plates

Introduction Tibial plateau fractures are intra-articular fractures and hence warrant anatomical reduction and stable fixation to promote early mobilization and good functional, clinical, and radiological outcomes. Though conservative treatment is reserved for undisplaced fractures, most of the fractures are displaced and hence require operative intervention. A bimodal distribution is observed in tibial plateau fractures with highenergy trauma being common in young patients and low-energy trauma being common in elderly patients. A road traffic accident involving a motorcycle is the most common cause of tibial plateau fracture [1]. Schatzker [2] classification is the most commonly described classification for tibial plateau fractures (Fig. 1). Schatzker I–IV can be classed as unicondylar fractures whereas Schatzker V–VI can be classed as bicondylar fractures. The incidence of complications such as stiffness and malunion are higher with bicondylar fractures compared with unicondylar fractures [3]. Schatzker type VI injuries are associated with significant soft-tissue injuries to the lateral collateral ligament, anterior cruciate ligament, and the menisci [4]. Hence, it is imperative to confirm the associated injuries using additional imaging investigations, such as MRI. Schatzker type VI injury is a significant risk factor for developing compartment syndrome of the leg [5]. The Schatzker classification was based on anteroposterior radiographic views. The three-column classification (Fig. 2) on axial CT by Luo et al. has described coronal plane fractures affecting the posteromedial and posterolateral aspects in high-energy trauma [6]. The utility of the classification is that the traditional locking plates applied on the anterolateral and anteromedial aspects of the proximal tibia do not effectively fix the fractures of the posterior column and hence buttress plating is undertaken separately of the involved posterior columns. Biomechanical studies have concluded that a coronal plane fracture line can compromise the

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Fig. 1 shows Schatzker classification (I – cleavage fracture of lateral tibial plateau; cleavage and depression fracture of lateral tibial plateau; III – depression fracture of lateral tibial plateau; IV – fracture of medial tibial plateau; V – bicondylar fracture with maintenance of continuity between epiphyseal and metaphyseal zones; VI – bicondylar fracture with no continuity between epiphyseal and metaphyseal zones)

stability of the medial part of the tibial plateau particularly on weight bearing [7–9]. A properly positioned buttress plate is the single most important step in stabilizing posteromedial fracture and a biomechanical study has reported that a conventional non-locking plate is as effective as a locking plate [10].

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Fig. 2 Three column classification by Luo et al. on axial views of CT scan. 3D CT scan images give better appreciation of the fractures affecting the posterior columns. The fracture lines in the posterior columns are depicted with red lines

Historical Aspects and Evolution of the Treatment of Tibial Plateau Fractures Internal Fixation Initially, tibial plateau fractures were treated conservatively but the results were poor due to failure to reduce the articular surface, stiffness, persistent pain, swelling, and early posttraumatic arthritis of the knee. Cast and cast bracing were used to treat tibial plateau fractures [11, 12]. Subsequently, these injuries were treated with skeletal traction and though the traction helped in achieving length at the fracture site, the results were good when traction was given along with early mobilization [13]. Then these fractures were treated with open reduction and internal fixation using cannulated cancellous screws. Though the screws helped in reducing the intraarticular fractures, there was a need to support the metaphyseal diaphyseal bone as well to prevent subsidence. Furthermore, there were issues of backing out of the screws on weight-bearing and failure of fixation. This led to the development and use of conventional buttress plates (T and L-shaped plates) and screws. In bicondylar fractures, the T and L-shaped conventional buttress plates were placed on the lateral proximal tibia and one-third tubular plate was placed on the medial proximal tibia. The conventional buttress plates were applied after the open reduction of the fractures and required larger skin incisions to fix the plates. This led to a high incidence of infection, wound breakdown, and skin necrosis. Since there was a loss of reduction in osteoporotic bones and comminuted fractures, anatomical and contoured locking plates (4.5 and 5 mm) having fixed angle stable configuration were developed which helped in achieving better results in these complex fractures. The advent of precontoured anatomical locking plates gave the freedom to the surgeons to use MIPPO (minimally invasive percutaneous plate osteosynthesis) techniques for the internal fixation of complex comminuted fractures at metaphyseal-diaphyseal locations. Some manufacturers also developed specialized external jigs (LISS – Less Invasive Stabilizing System) for passing screws

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through small incisions. The MIPPO technique has led to reduced incidence of skin infection, minimal disruption of the vascularity, soft tissue envelope, and fracture hematoma around the fracture site thereby leading to better union rates and better functional outcomes due to early and safe mobilization. The initially used 4.5 and 5 mm precontoured locking plates were bulky and prominence through the skin and soft tissues paved the way for the development of 3.5 mm fixed angle precontoured locking plates. The 3.5 mm locking plates also gave the option for passing more screws in the proximal holes of the plate thereby conferring a “raft” effect on the subchondral bone. The column theory propagated by the Luo classification helped a better understanding of some fracture patterns including the coronal fracture pattern involving the posteromedial and posterolateral surfaces of the tibial plateau. This led to the development of 3.5 mm precontoured locking plates that are designed to be applied on the posterior aspect of the proximal tibia. Presently, variable angle precontoured anatomical locking plates have been developed which give freedom to the surgeons to pass screws without breaching the articular surface or without coming in conflict with the direction of other screws. With the advent of advanced imaging techniques such as 3D CT reconstruction and MRI, certain uncommon fracture patterns have been recognized which are small in size but have an effect on the stability of the knee joint and consequent functional outcomes. Since these fractures cannot accept the standard commonly used screws but warrant fixation due to capsular or ligamentous attachments, specialized 2.7 mm locking rim plates can be used from the hand or foot and ankle set. These small plates can be negotiated under the collateral ligaments and screws can be placed anterior and posterior to the ligaments without breaching them.

Bone Grafts and Substitutes Furthermore, initially, cancellous autografts were used to maintain the height of the articular surface after surgically elevating the depressed articular surface. Presently, bone graft substitutes available in various forms (solid croutons, injectable liquid) are being used to effectively maintain the void after the elevation of the articular surface.

External Fixation Initially, rod and clamp external fixator was used for applying principles of ligamentotaxis for indirect reduction of intra-articular fractures and also comminuted fractures at the metaphysis. Though used for open fractures, these were used for closed fractures with severe soft tissue injury and in complex fracture patterns that were not amenable to internal fixation. The popularity of external fixators also increased due to the avoidance of surgical incisions and wound healing issues. The rod and clamp external fixators were used initially as definitive methods of fixation. Since the rod and clamp fixators were applied across the knee, there was a high

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incidence of knee stiffness due to prolonged immobilization. This prompted the need to prevent across-knee configuration and led to the use of circular fixators. The circular ring fixators were bulky and being circumferential had issues with patient satisfaction and acceptability. Hence, the hybrid fixator was developed that involved the use of the ring fixator proximally and the rod and clamp fixator distally. Presently, external fixators are used as a temporary modality of treatment even in open fractures and closed fractures till the local condition becomes amenable to safe internal fixation.

Evidence from Biomechanical Studies Extra-articular Comminuted Proximal Tibial Fracture A biomechanical study on synthetic bones reported that fixation using intramedullary expert tibial nails was stronger compared to fixation using a single lateral locking plate or dual locking plates [14]. A finite element analysis study observed that fixation using dual locking plates was stronger compared to standard intramedullary interlocking tibial nails [15]. A recent study on synthetic bones concluded that dual locking plates were stronger compared to the use of a single lateral locking plate, combined used of lateral locking plate and interlocking intramedullary tibial nail or the use of isolated interlocking intramedullary tibial nail [16].

Schatzker I Fracture Parker et al. [17] performed a biomechanical study on human cadavers and observed that there was no difference between the uses of either two or three lag screws. Furthermore, the use of an additional anti-glide lag screw below two proximally placed lag screws did not confer an additional biomechanical advantage. Another study [18] on human cadavers reported no difference between the use of two 6.5 mm cancellous lag screws, three 6.5 mm cancellous lag screws, two 6.5 mm cancellous lag screws with 4.5 mm cortical screws as anti-glide screw or the use of L-shaped buttress plate and screws. The authors concluded that the use of two 6.5 mm cancellous lag screws were sufficient to fix Schatzker I fracture.

Schatzker II Fracture A biomechanical study on synthetic bone models reported that cement augmentation and lateral angle stable L-shaped buttress plate fixation was stronger than cement augmentation and screw fixation [19]. Another study on human cadavers observed that designs using screws passing through the proximal holes of the plate are stronger compared to designs wherein screws are passed separately superior to the

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plate [20]. Since locking and non-locking screws provide equivalent stability, the routine use of locking screws in this fracture pattern is not justified biomechanically.

Schatzker III Fracture A study on synthetic bone models [21] reported that the placement of four 3.5 mm cortical screws as “rafting” screws was biomechanically stronger and more effective instead of using two 6.5 mm cancellous screws. On human cadavers, Mayr et al. [22] observed that in addition to cement augmentation, additional support using 3.5 lateral locking plates was biomechanically stronger compared to additional support using four 3.5 mm cortical raft screws. A recent biomechanical study [23] concluded that cement augmentation and lateral angle stable plate fixation was stronger than cement augmentation and screw fixation.

Schatzker IV Fracture Wu and Tai [24] evaluated synthetic bone models and observed that a T buttress plate applied on the medial surface provided more effective stability compared to a buttress plate applied on the lateral surface of the proximal tibia. Two biomechanical studies favored fixation with T plates compared to cannulated cancellous screws [25, 26].

Schatzker V Fracture A study on synthetic bones reported that LCP locking plate was stronger than the hybrid external fixator and the L plate [27]. Another study [28] observed that a 3.5 mm locking plate and a 4.5 mm locking plate have equivalent biomechanical strength.

Schatzker VI Fracture A human cadaver study reported less subsidence with dual conventional plating (4.5 mm non-locking proximal tibial plate on the lateral side and one-third tubular plate medially) compared to a single 4.5 angle stable lateral locking plate [29]. Another recent study on cadavers reported contradictory results with single lateral locked plating [3.5 mm raft screws plate] being as strong as dual plating [lateral locked plating and medial one third tubular plate] [30]. A study on sawbones reported that the triangular pattern of screws passed through the upper holes of the lateral locking plate was more effective than the horizontal pattern of screws passed through the upper holes in preventing displacement of the medial tibial plateau [31]. A biomechanical study on simulated Schatzker VI fracture with a posteromedial

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fragment on synthetic bones observed that dual plating using conventional plates was stronger than single-locking plating [32]. In the combination of a 3.5 mm lateral non-locking plate, the use of a third tubular plate on the posteromedial fragment is recommended instead of the use of an LC-DCP.

Fundamental Principles of Fixation of Tibial Plateau Fractures Guiding Principles and Crucial Concepts The choice of implant depends on the following: location of the fracture (subchondral/metaphyseal/diaphyseal/juxta-articular cortical), size of the bony fragment (small/large), the pattern of the fracture (Schatzker/Luo), involvement of one or both the tibial plateaus, comminution (absence/presence), quality of underlying bone (normal/osteoporotic) and quality of the surrounding soft tissues (open fracture/ closed fracture with extensive blisters). The objective of internal fixation of tibial plateau fractures is stable fixation and early mobilization. For simple articular fractures of the tibial plateau, lag screws are recommended whereas, for complex multi-fragmentary articular fractures, positioning screws are recommended (avoid lag screws because it will lead to over-tightening and mediolateral narrowing of the joint). The use of a fully threaded screw in non-lag mode is recommended. For simple fractures of the tibial metaphysis and diaphysis, absolute stability is recommended, whereas, for complex fractures involving the metaphysis and diaphysis, relative stability is recommended using indirect reduction methods and minimally invasive percutaneous plating technique is recommended to minimize longer surgical incisions with the consequent risk of infection, wound-healing problems, and bone-healing problems. Lag screws have to be inserted perpendicular to the primary fracture line to generate optimal compression. However, care has to be taken in extremely comminuted intra-articular fractures since over-compression due to the lag effect can lead to the narrowing of the tibial plateau. Lag screws can be placed either above the plate or through the proximal holes of the plate depending on the fracture pattern. In a young patient with good bone quality, the use of partially threaded cancellous screws is sufficient, whereas in the elderly patient with poor bone quality, the use of fully threaded cancellous screws is preferred. Buttress plates tend to compress one fracture segment against the other intact bony fragment in intra-articular fractures and are designed to counter vertical shear forces during weight bearing. The buttress plates tend to provide the support most commonly on the lateral side for the cortical breach as seen in the lateral wall comminuted cortical bone. Since these are usually precontoured plates, they tend to fit well on the part of the bone they are usually designed to be used on. Slight under-contouring is acceptable since it produces an effective buttressing effect. Overcontouring of the plate should be avoided. For effectively using a plate as a buttress, all screws proximal to the fracture must be placed eccentrically distally in

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the screw hole, whereas all screws distal to the fracture must be placed eccentrically proximally in the screw hole. The prerequisites for the use of conventional non-locking buttress plates and screws include good soft tissue envelope and good bone quality, simple tibial plateau fracture patterns, and non-comminuted fracture. Anti-glide plates are designed to primarily oppose shearing forces at the fracture site. The position of the anti-glide plate at the fracture site is important and here the role of a CT scan is very crucial. The anti-glide plates have to be placed at the apex of the fracture site and the initial screw should be placed just below the apex and very close to the fracture site to achieve the optimal anti-glide effect and effective compression of the plate against the proximal tibia. The anti-glide plate is usually applied on the medial, posteromedial, or the posterior aspect of the medial tibial plateau. Under contouring of the plate helps to achieve the optimal anti-shearing effect. The tendency to accurately contour the plate over the medial plateau surface should be avoided. Also, repeated contouring and straightening of the plate should be avoided. If one needs to err, it is better to err on the side of under-contouring the plate. Non-locking conical and cortical screws tend to provide interfragmentary compression by pressing the plate to the surface of the bone. Locking screws do not provide compression of the plate to the underlying bone. Hence, if reduction of the fracture is required, it is better achieved through a non-locking screw placed through the plate. If the locking screw has been placed and if reduction of fracture is required, then the locking screw has to be loosened first so that all threads on the screw head disengage completely from the threaded holes. The reduction should be done and then the locking screw should be re-tightened. The advent of locking plates and screws has minimized the chances of fixation failure that was observed in conventional plates and screws. Since the locking plates do not essentially need to be flush to the bone, they are also called internal fixators. The prerequisites for the use of plates with angular stability (Internal fixator) include closed fracture with significant soft tissue injury, poor bone quality, complex articular fracture patterns and comminuted fractures of the metaphysis and diaphysis. 4.5/ 5.0 mm plates are less malleable, slightly more bulky, and difficult to contour. However, they are stronger and are preferred for tibial plateau fractures associated with metaphyseal-diaphyseal comminution. Raft screws are placed subchondral parallel to the knee joint and are designed to prevent the displacement of the elevated articular fragments. They are not designed to provide compression. If compression is desired then lag screws have to be inserted. The raft screws can usually be inserted through the upper holes of the plate. The positioning of the plate is the single most important step in addition to the preliminary reduction and temporary fixation of the intra-articular fracture. If the plate is inadvertently placed distally then the screws through the upper hole would be unable to provide the rafting effect to the subchondral bone thereby leading to the collapse on weight bearing. If the plate placement is distal or if the plate does not allow the insertion of raft screws, then it is imperative to place the raft screws separately and superior to the plate to provide effective rafting support. If the raft plate is placed too proximally then the raft screws placed through the upper hole are

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at risk of unacceptable joint penetration. The distance of the raft screws from the joint line is a predictor for loss of reduction in tibial plateau fractures [33].

Skeletal Traction Indication Steinmann pin is inserted in the distal tibia in cases with significant displacement and shortening or knee subluxation to correct the limb alignment.

Description They are available in a diameter of 4 mm, 4.5 mm, and 5.0 mm. It is used along with the above-knee back slab for additional support. Skeletal traction with the help of ligamentotaxis helps to align the fracture and reduce pain and swelling. This is deployed as a temporary method of treatment before definitive treatment.

External Fixator Indications Open grade III fractures of the proximal tibia, closed fractures with significant soft tissue swelling (hemorrhagic blisters, compartment syndrome) wherein the local skin condition and devitalized soft tissue condition precludes safe internal fixation and as part of damage control orthopedics in the management of multiply injured patient with tibial plateau fracture.

Advantages It is usually used as a temporary measure for immobilization before definitive management. It can also be used intra-operatively to hold the reduction while the surgeon performs definitive internal fixation.

Disadvantages Since the fixation device lies outside the body, there is a risk of pin tract infection and also the potential for septic arthritis if limited internal fixation is performed or if the pin lies in the vicinity of the knee joint. The prevalence of infection is higher in external fixation compared to internal fixation for tibial plateau fractures [34]. Another cause for concern is the cosmesis aspect.

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Modalities Pin and Rod Fixator • It is used as an across-knee spanning fixator wherein the tibial plateau fracture. • Angulation, translation and rotational deformities are corrected during the application of the external fixator. • Gross acceptable reduction needs to be attained and in most fracture patterns, it is difficult to attain anatomical reduction. • Two 5 mm Schanz pins are inserted in the femur and two 5 mm Schanz pins are inserted in the tibia away from the proposed incision sites and away from the joints. The Schanz pins should be arranged in a near-near far-far configuration (the Schanz pins in each bone should be spread apart to increase the strength of the construct). • This is usually used as a temporary method of fixation before definitive fixation. Ring Fixator • A ring frame fixator can be used and bridging the knee joint can be avoided if adequate interfragmentary compression at the tibial plateau can be achieved with the use of tensioned olive wires. Sometimes, limited open reduction is done and 6.5 mm cannulated cancellous screw fixation is done and a ring fixator is applied for additional stability. • Avoidance of the use of a full ring around the knee joint would allow some range of motion at the knee joint. • However, since the ring fixator frame is bulky and disfiguring, the rate of patient dissatisfaction is high with this modality. Hence, patients have to be appropriately counselled before the use of this treatment modality. • However, a ring fixator is a versatile modality of treatment that allows the surgeon to deal with bone loss and correction of multiplanar deformities. This is best performed by fellowship-trained limb reconstruction surgeons and hence better to be avoided by general trauma orthopedic surgeons. • This is used as a definitive modality of fixation. Hybrid Fixator • This combines a ring fixator frame proximally at the periarticular site and is supplemented by the pin and bar frame distally at the diaphyseal location. Circumferential rings distally around the leg are avoided in this treatment modality. • This is usually used as a temporary method of fixation and very rarely used as a definitive method of fixation as well.

Cannulated Cancellous Screws (6.5 mm CCS) Indications Schatzker I fracture (AO – Type B1) with intact cortex over the place of screw insertion and simple fracture pattern in young patients with good bone quality. There should be no comminution at the metaphyseal fracture site.

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Fig. 3 6.5 mm CCS inserted across Schatzker I fracture (AO – Type B1)

Description The 6.5 mm cannulated cancellous screw is used as a lag screw to compress the lateral tibial plateau against the intact medial tibial plateau. It is available with 16 mm and 32 mm thread lengths. For the Schatzker I fracture, usually a 32 mm thread length screw is used. The lag effect is provided by the smooth shaft portion of the cannulated cancellous screw. Since these screws are not self-tapping, the near cortex will need to be tapped. If adequate closed reduction is achieved by indirect methods then the screws can be inserted percutaneously. A percutaneously inserted ball tip reduction clamp is helpful to hold the reduction. Usually, two 6.5 mm CC screws along with washers are inserted parallel to each other just below the joint lines (Fig. 3). The 13 mm washer has a flat side that rests against the bone cortex and has a conical side as well on which the screw head lies. The function of the washer is to evenly distribute the pressure of the screw head and prevent the screw head from perforating the thin cortex of the epiphyseal and metaphyseal location of the proximal tibia. Some surgeons prefer to use a 4.5 mm cortex screw with a washer placed at the inferior apex of the fracture line to provide an anti-gliding effect.

L Buttress Plate Indications Those fractures of the lateral tibial plateau having comminution of the lateral cortex are best fixed using an L buttress plate in young patients with good bone quality and good surrounding soft tissue envelope (Extra-articular metaphyseal fractures, Schatzker I, II). Furthermore, the size of the proximal segment should be large enough to comfortably accommodate 6.5 mm lag CCS through the upper holes of

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the plate. In Schatzker II fracture, the articular fragment that needs elevation should be singular and large enough to be supported by the 6.5 mm CCS of the proximal hole of the L buttress plate. On the lateral side, the posterior part of the horizontal limb of the L plate does not abut the fibular head and thereby more effective buttressing effect is created by the L plate compared to the T plate. In comminuted lateral wall fractures, CCS would perforate the lateral cortex despite the use of washers due to the proximity of the fracture.

Description The L buttress plate is designed to act as an anti-glide plate to resist longitudinal deforming forces at the knee joint and they provide no angular stability. The L buttress plate is precontoured to fit the lateral proximal tibia, and it is a thin plate that permits satisfactory apposition of the plate by the insertion of standard non-locking screws that compress the plate against the bone. Firstly, a 4.5 mm cortical screw is inserted in the oval hole of the plate. This screw can either be placed centrally and this would give the freedom to slide the plate slightly proximally or distally for adjusting the position of the plate. Alternatively, if the height of the plate is correct then the cortical screw can be placed in the proximal part of the oval hole to effectively function as an anti-glide plate (Fig. 4). Then, 6.5 mm cannulated cancellous screws are inserted in the screw holes of the proximal horizontal limb of the plate followed by the insertion of 4.5 mm cortical screws in the DCP holes of the distal vertical limb of the plate. The previous design of the L buttress plate allowed the placement of only 4.5 mm cortical screws through round holes but the present design of the L buttress LCP plate has combi-holes that allow the placement of either cortical non-locking screws or locking cortical screws in the diaphyseal part of the tibia. The L buttress plate is side specific and is available separately for the right and left sides.

T Buttress Plate Types of T Buttress Plates (Fig. 5) The T buttress plate to be placed on the lateral aspect of the proximal tibia has a precontoured double bend to accommodate the curve of the lateral proximal tibia. The T buttress plate to be placed on the anteromedial aspect of the medial tibial plateau has a single smooth curve.

Indications The prerequisites for using a T buttress plate include the presence of good quality bone, adequate and good surrounding soft tissue cover, and the presence of an intact cortical wall that will permit the insertion of proximal lag screws (6.5 mm CCS). The lateral T

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Fig. 4 The fracture is depicted as red interrupted line. For effective functioning of the Buttress plate as an antiglide plate, the 4.5 mm cortical screw (yellow circle) should be placed just below the fracture. This can be done accurately under fluoroscopy guidance intraoperatively. In most cases, the 4.5 mm cortical screw is placed eccentrically proximally in the oval hole

Fig. 5 Comparison of profiles of T buttress plates on the tibia bone model

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buttress plate is used for extra-articular tibial plateau fractures and Schatzker I, II, III, V, and VI fractures. The medial T buttress plate is used for Schatzker IV fracture.

Description The T buttress plate is designed to act as an anti-glide plate to resist longitudinal deforming forces at the knee joint and they provide no angular stability. The T buttress plates for the lateral tibial condyle (Fig. 6) and medial tibial condyle (Fig. 7) are thin and malleable. They can be accurately contoured to fit the contour of the condyles and the insertion of non-locking screws will firmly fix the plate to the bone. Cannulated cancellous screws of 6.5 mm are inserted in the screw holes of the proximal horizontal limb of the T buttress plate. A 4.5 mm cortical screw is inserted bi-cortically in the oval hole of the plate. Cortical screws of 4.5 mm are inserted in the DCP holes of the distal vertical limb of the plate. The only disadvantage is that on the lateral side, the posterior part of the horizontal limb of the T plate might abut on the fibular head and prevent effective buttressing of the lateral tibial plateau fracture. The previous design of the L buttress plate allowed the placement of only 4.5 mm cortical screws through round holes but the present design of the L buttress LCP plate has combi-holes that allow the placement of either cortical non-locking screws or locking cortical screws in the diaphyseal part of the tibia. Fig. 6 T buttress plate for lateral tibial plateau having double bend

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Fig. 7 T buttress plate for medial tibial plateau having single smooth bend

One-Third Tubular Plate and Reconstruction Plate Indications The one-third tubular plate and reconstruction plates are used as a buttressing plates on the medial tibial condyle in bicondylar fractures (Schatzker V and VI). The advantages of using these plates are the ease of contouring and molding of the plate, the low profile plate and the effectiveness in maintaining the stability of the medial condyle. Biomechanical study on human cadavers simulating posteromedial shear fracture patterns has shown that conventional plates such as DCP and one-third tubular plates are as stiff as modern locking plates in providing the buttressing effect [10]. These plates can also be placed over the tibial tuberosity for fractures involving the tibial tuberosity that are not amenable to lag screw fixation due to cortical comminution.

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Fig. 8 One third tubular plate on the posteromedial border of the medial tibial condyle

Description The one-third tubular plate is placed on the posteromedial border of the tibia if the apex of the medial condyle fracture is centered on the posteromedial border (Fig. 8). The reconstruction plate can be for fractures involving the medial condyle and also for posterior shear fractures of the tibial condyles (Fig. 9). The reconstruction plate needs to be contoured accurately to effectively function as a buttress anti-glide plate.

Lateral Tibial Head Buttress Plate 6.5 Indications This plate is used for fractures of the lateral tibial plateau (Schatzker I) that are associated with the fracture of the tibial diaphysis. This is used in patients with good bone quality and good soft-tissue cover.

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Fig. 9 Reconstruction plate used for fractures involving the medial condyle

Description The plate has a broad upper part that has a shape similar to a hockey stick hence this plate is referred to as a hockey stick plate (Fig. 10). Cannulated cancellous screws of 6.5 mm are passed through the upper five non-locking screw holes and hence this plate has no angular stability. The distal straight shaft portion of the plate has non-locking combi holes through which 4.5 mm cortical screws can be placed either in “buttressing” mode or “compression” mode. Both these concepts are depicted in Fig. 10. The plate is side specific and hence available separately for the right and left sides.

LCP – Proximal Lateral Tibial Plate 5.0 Indications This plate is used for fractures of the lateral tibial plateau (Schatzker I, II, III, V and VI) that are associated with the fracture of the tibial diaphysis. Since it is possible to place locking screws in both the proximal head and distal shaft parts of the plate, it provides angular stability (Fig. 11). This plate is suited for osteoporotic bone. This

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Fig. 10 Lateral tibial head buttress plate that has non-locking proximal screw holes for 6.5 mm CCS. Illustration of tibial condyle fracture (A) with shaft fracture (B) with 4.5 mm cortical screws (yellow circles). The upper two 4.5 mm cortical screws have been placed in buttress mode (closer to the proximal part of the screw holes) and the distal third 4.5 mm cortical screw has been placed in the dynamic hole of the DCP portion of the plate to provide compression at the diaphyseal fracture

plate system is not recommended for those fractures wherein the segment proximal to the fracture is too small to accept 6.5 mm CCS.

Description The plate is anatomically precontoured to sit on the lateral proximal tibia. The proximal curved and broad part of the plate has five holes arranged in a staggered manner that accepts 5.0 mm locking screws. Since the plate sits distally to the tibial flare and since the proximal holes accept locking cancellous screws, primary compression at the condylar fracture can be achieved by inserting lag screws proximally outside the plate (Fig. 12). The distal straight shaft part has combi holes that accept either a 4.5 mm cortical non-locking screw or a 5 mm locking screw. At least 4 screws each should be placed in the proximal segment and the distal segment. The plate is side specific and hence available separately for the right and left sides. The size of the plate

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Fig. 11 LCP – Proximal lateral tibial plate 5.0 with tiny holes to pass 2 mm Kirschner wires for temporary fixation and troughs on the side of the plate to hold the plate to the bone using ball tip reduction clamps

(size 5 to 13) is determined by the number of holes in the shaft portion of the plate. The plates are designed to be anatomically shaped and precontoured to match the shape of the underlying bone hence additional bending or twisting of the plate is not recommended since it can weaken the plate. The plate can either be applied after open reduction and internal fixation or be applied without opening the diaphyseal component of the fracture using the minimally invasive percutaneous plate application (MIPPO) technique. The plate is slid extraperiosteally under the musculature of the anterior compartment of the leg. This consequently causes less disruption of the vascularity of the tibia from the periosteal side.

LCP – Lateral Proximal Tibial Plate 4.5 (Raft Plate 4.5) Indications This plate is used for fractures of the lateral tibial plateau (Schatzker I, II, III, V and VI). Since it is possible to place locking screws in both the proximal head and distal shaft parts of the plate, it provides angular stability. This plate is specially designed to provide subchondral support to the elevated articular bone fragment(s).

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Fig. 12 Lag screws can be placed proximal to the plate (yellow rectangle) in order to gain compression of the tibial condyle fracture

Description This is an anatomically precontoured, fixed-angle locking compression plate that is applied on the lateral aspect of the proximal tibia. It is side specific and is available for the right and left sides. The plate has an upper horizontal part and a lower vertical part. The upper part has three locking screw holes that accept 5 mm cannulated locking screws or 5 mm cannulated conical screws. The proximal three screws must not be bicortical to avoid irritation of the medial collateral ligament of the knee. If interfragmentary compression is required at the articular surface, the first screw inserted should be the 5.0 mm cannulated conical screw. On the contrary, if the 5.0 mm cannulated locking screw is inserted, then subsequent insertion of the cannulated conical screw will not give any compression. After the insertion of one 5.0 mm cannulated conical screw, the rest of the two screws inserted are the 5.0 mm cannulated locking screws. Since the proximal cannulated locking screws are inserted in a convergent configuration, care has to be taken to insert the plate on the lateral aspect of the proximal tibia anterior to the fibula. If the plate is applied on

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the anterolateral aspect of the proximal tibia, there is a likelihood of the screws breaching the posterior cortex and thereby endangering the posterior neurovascular structures. The combi-holes in the distal vertical part permit the use of either a 4.5 mm cortical screw or 4 mm locking screw or 5 mm locking screw. Non-locking cortical screws should be inserted before the insertion of the locking screw to make the plate flush with the shaft of the tibia. There are three holes proximal to the combiholes. The proximal two holes are round and either a 6.5 mm Cannulated Cancellous screw or a 4.5 mm cortical screw can be inserted through them. The distal-most of the three holes is an angled locking hole through which a 5 mm locking cannulated cancellous screw is inserted to buttress a fracture of the medial tibial plateau.

LCP – Lateral Proximal Tibial Plate 3.5 (Raft Plate 3.5) Indications This plate is indicated primarily for Schatzker II, III wherein the size of the fracture fragment is small and precludes the application of the LCP proximal tibial plate 4.5. It can also be used for stabilization of the lateral column in Schatzker V and VI injuries along with the use of different plating stabilization of the medial column.

Description This plate combines the principles of anatomically precontoured, fixed angle construct with locking screw plate technology along with traditional plating. This plate works on the principle of using raft screws to buttress and support the subchondral articular fragment. As the diameter of the screws decreases, more number of locking screws can be placed proximally to support the articular fragments after elevation of the depressed fracture fragments. It is side specific and hence available separately for right and left sides. It has two parts: the proximal transverse limb and the distal vertical limb (Fig. 13). There are four locking screws holes that accept 3.5 mm locking screws. The proximal screws are parallel to each other (Fig. 13). Even non-locking 3.5 mm screw can be inserted if lag screw effect is needed to achieve interfragmentary compression at the articular fracture site. In cases of extreme fracture comminution, lag screw effect is not recommended in order to avoid over compression of the articular surface. Since the proximal screws provide “rafting” effect, the plate is designed to sit proximally on the lateral tibial plateau flare. The ideal positioning of the plate is demonstrated in Fig. 14. Too high placement of the plate can lead to intraarticular perforation of the screws mainly on the concave upwards medial tibial plateau and distal placement of the plate will lead to ineffective provision of raft effect and risk depression of the elevated articular fragments (Fig. 15). Partially threaded 3.5 mm non-locking screw is usually preferred for achieving lag screw compression effect in young adults with good bone stock. Fully threaded 3.5 non-locking screw usually preferred for achieving lag screw compression effect in elderly patients with poor bone

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Fig. 13 LCP lateral proximal tibial raft plate 3.5 showing plate design and ideal screw configuration in the proximal locking screw holes. The distal shaft has combi holes. There is a hole (yellow arrow) distal to the last combi-hole that permits the attachment of articulated tensioning device if additional compression is desired by the surgeon

stock. In the distal vertical limb, there are three screws holes proximally that orient the 3.5 mm locking screws obliquely so that they converge towards the medial tibial plateau on the coronal plane. The screw size should reduce by 5 mm as one goes distally to the last oblique locking screw. Different manufacturers have designed various options for screw holes in the distal shaft. Some manufacturers provide combi-holes that accept 3.5 mm non-locking cortical screw or 3.5 mm locking screws (Fig. 13), whereas other manufacturers provide separate holes for locking screws and for dynamic non-locking screws (Fig. 14). There is a hole terminally to admit the

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Fig. 14 Ideal placement of the plate on the lateral tibial plateau. The distal shaft has separate holes for locking screws and non-locking screws

Fig. 15 consequence of too high placement (left figure) and too distal placement (right figure)

articulated tensioning device (Fig. 13). This device is used to achieve primary compression in simple fracture patterns and is usually not recommended for complex comminuted metaphyseal fracture patterns.

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LCP – Medial Proximal Tibial Plate 4.5/5.0 Indications This plate is indicated for Schatzker IV fractures with a fracture pattern that is better fixed using a plate and screws on the anteromedial surface of the tibial plateau. This plate is most suitable for medial condyle fractures that are associated with significant depression of the articular fragment. After elevation of the depressed fragment and insertion of bone graft or bone graft substitute, this raft plate and screws are effective in preventing re-displacement of the articular fragments. The apex of the fracture should be on the anteromedial surface or the medial border of the tibial condyle surface.

Description The T-shaped, fixed-angular stable plate is contoured to fit onto the anteromedial surface of the medial tibial plateau. It has a smooth contour to approximate the medial tibial condyle flare. It is available separately for the right and left sides, and hence it is imperative to use the correct side plate for the fracture. The upper transverse part of the plate has three locking screw holes to accommodate three 5.0 mm non-locking conical or cannulated locking screws that act as raft screws to support the subchondral bone after elevating the depressed articular fragment. There are small holes proximal to the upper screw holes that are used for passing temporary 2 mm Kirschner wire for provisional plate fixation and also for passing meniscal sutures whenever a submeniscal arthrotomy approach is used. The distal vertical part of the plate has a limited contact plate design thereby reducing the compression effect on the periosteal blood vessels. There are two angled holes that permit the passing of two 5.0 mm locking screws in an oblique trajectory. The combi holes in the vertical limb of the plate allow the introduction of 4.5 mm cortical non-locking screws and 5.0 mm locking screws.

LCP – Medial Proximal Tibial Plate 3.5 Indications This plate is indicated for Schatzker IV fractures with a fracture pattern which is better fixed using a plate and screws on the medial surface of the tibial plateau. This plate is most suitable for medial condyle fractures that are associated with significant depression of the articular fragment. After elevation of the depressed fragment and insertion of bone graft or bone graft substitute, this raft plate and screws are effective in preventing re-displacement of the articular fragments. This plate is particularly useful when the surgeon decides that the articular fragments are small enough to be effectively held in position by the 5 mm proximal screws of the LCP medial proximal tibial plate 4.5/5.0. Furthermore, the medial proximal tibial plate 3.5 is less bulky compared to the 4.5 plate system. The overall build of the patient along

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with local anatomy will decide the appropriateness of the plate system to be used by the surgeon. Also, this plate system is used for Schatzker V and VI fractures wherein dual plate fixation is necessary. The medial condyle fracture pattern should be such that the apex of the fracture should lie on the medial border.

Description The oblique T-shaped LCP plate is contoured to fit onto the medial surface of the medial tibial plateau. The plate has a smooth curve that approximates the medial tibial condyle flare (Fig. 16). The oblique T is incorporated to mimic the native posterior tibial slope in the sagittal plane and hence this plate is side specific (Fig. 16). The upper screw holes in the oblique T part of the plate accommodates three 3.5 mm non-locking conical or locking screws that act as raft screws to support the subchondral bone after elevating the depressed articular fragment. The upper row screws are oriented parallel

Fig. 16 Ideal placement of the LCP medial proximal tibial plate 3.5 onto the medial surface of the proximal tibial plateau. The upper part of the plate is angled slightly posteriorly (saffron line) to match the natural posterior tibial slope (dark blue line)

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Fig. 17 The parallel orientation of the locking screws in coronal and axial planes

to each other in all the planes (Fig. 17). The distal vertical part of the plate has two angled holes that permit the passing of two 3.5 mm locking screws in an oblique trajectory. The combi holes in the distal vertical limb of the plate allow the introduction of 3.5 mm cortical non-locking screws and locking screws.

LCP Posteromedial Tibia Plate 3.5 Indications This plate is indicated in the Schatzker IV fracture with the apex of the fracture lying at the posterior or the posteromedial surface of the medial condyle, shear-type coronal split fracture involving the posterior part of the medial condyle and in Schatzker V and VI fractures wherein the apex of the fracture lie at the posterior or the posteromedial surface of the medial condyle and the medial condyle fracture is comminuted, unstable, and the bone quality is poor.

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Description The locking angular stable plate is precontoured to fit the posteromedial part of the medial tibial condyle (Fig. 18). There are three locking screw holes in the upper part in an inverted triangle configuration with two holes lying proximally at the same level and the third hole lying distally. The locking screws through the upper holes are angled to orient 3 inferior to the horizontal plane on the sagittal view to avoid penetrating the concave upwards surface of the medial tibial plateau (Fig. 19). On the axial plane, the proximal screws diverge by 5 (Fig. 20). Since there is a 7 posterior slope in the upper tibia, the locking screw through the distal single locking hole is angled 15 superior to the horizontal plane on the sagittal view to engaging the anterior proximal bone (Fig. 19). The upper holes can accept a 4 mm cancellous screw, 3.7 mm cannulated locking screw, 3.7 mm conical screw, 3.5 mm conical screw, and 3.5 mm locking screw. In the distal part of the plate, there is an elongated hole in the upper part of the shaft through which a 3.5 mm cortical screw is inserted. The elongated hole gives freedom to adjust and properly position the plate and also to effectively apply the buttressing effect (Fig. 21). The 3.5 mm cortical screw is inserted in the lower part of the elongated hole just below the primary fracture line. Furthermore, this screw need not be bicortical and a screw just short of the anterior tibial cortex will still be sufficient and buttress the plate to the bone. There are combi holes in the distal part of the shaft through which a 3.5 mm cortical or locking screw can be inserted. The plate has a limited contact profile thereby leading to the

Fig. 18 Ideal placement of the LCP posteromedial tibial plate 3.5

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Fig. 19 Illustration of the plate on the posterior surface with a simulated fracture (dark blue line)

Fig. 20 The screw divergence on the axial plane with a simulated fracture (dark blue line)

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Fig. 21 Close-up picture of the plate with an elongated screw hole that allows freedom for altering the position of the plate intraoperatively

preservation of the underlying periosteal blood supply to the bone and minimizing the stress-shielding effect of the plate.

Variable Angle LCP Proximal Tibial Plate 3.5 Indications The VA LCP proximal tibial plate 3.5 is used for Schatzker II, III, V, and VI fractures, wherein it is deemed necessary to capture posterior column injuries as well.

Description The variable angle locking option allows the surgeon to voluntarily choose the direction of screw placement and also the option to “lock” the screw to the screw hole. The surgeon has the option to alter the direction of the locking screw by 15 in any direction to avoid perforating the articular surface or to avoid another screw. The plate is available in two forms: small bend and large bend. The appropriate plate is the one that fits the proximal tibia after adequate reduction of the fracture. The surgeon needs to be aware that subtle subluxation and consequent widening due to inadequate fracture reduction might erroneously lead the surgeon to choose the large bend plate instead of the small bend plate. The difference in the bends is to accommodate the proximal tibia of various genders and races. The plate is available separately for the right and left sides. The plate can be described as having an upper epiphyseal part, a middle metaphyseal part and a distal diaphyseal part. The upper epiphyseal part has six locking holes through which 3.5 mm locking screws can be passed. There are four holes in the upper row and two holes in the distal row. The middle metaphyseal part has three screw holes. There is an upper oblique hole for passing a 3.5 mm locking screw. The screw trajectory converges toward the medial tibial plateau. There is a middle oval hole for passing the first 3.5 mm cortical screw to fix the plate firmly to the bone. There is a lower oblique hole for passing a 3.5 mm locking screw. The screw trajectory converges toward the medial tibial plateau. There are combi holes in the distal diaphyseal part through which either 3.5 mm cortical screws or 3.5 mm locking screws can be passed.

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Rim Plate Indications It is mainly used for capturing juxta-articular cortical bones that are too small to be reliably fixed with screws, have attachment of capsular and ligamentous structures or lie in the vicinity of crucial neurovascular structures that precludes extensive surgical approaches for all columns.

Fig. 22 The application of rim plates in tibial plateau fractures

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Description The rim plate is used to restore cortical continuity in the subarticular location. It can be inserted deep to crucial structures (neurovascular structures, capsule, ligaments), and it is not required to pass screws through the central part of the plate. Since there are no specifically designed plates for the use in juxta articular fractures with extensive subarticular cortical Comminution, the plates need to be carefully molded to fit the surface on which they are applied. The plate tends to fit on the cortical rim horizontally and screws are passed at the edges of the plate bypassing the central cortical comminuted zone. Usually 2.4 mm and 2.7 mm plates either from the handset or the foot and ankle set can be used for this purpose (Fig. 22). These plates have been placed on the medial cortical rim [35], posterolateral juxta-articular cortical rim [36], and the posterior juxta-articular cortical rim [37, 38]. One third tubular plates have also been used for this purpose [35, 37].

References 1. Reátiga Aguilar J, Rios X, González Edery E, De La Rosa A, Arzuza OL. Epidemiological characterization of tibial plateau fractures. J Orthop Surg Res. 2022;17(1):106. https://doi.org/ 10.1186/s13018-022-02988-8. 2. Schatzker J. Compression in the surgical treatment of fractures of the tibia. Clin Orthop Relat Res. 1974;105:220–39. 3. Stefanelli F, Cucurnia I, Grassi A, Pizza N, Di Paolo S, Casali M, Raggi F, Romagnoli M, Zaffagnini S. Post-operative complications of tibial plateau fractures treated with screws or hybrid external fixation. Musculoskelet Surg. 2022;106(4):469–74. https://doi.org/10.1007/ s12306-021-00726-7. 4. Yan B, Sun J, Yin W. The prevalence of soft tissue injuries in operative Schatzker type IV tibial plateau fractures. Arch Orthop Trauma Surg. 2021;141(8):1269–75. https://doi.org/10.1007/ s00402-020-03533-0. 5. Deng X, Hu H, Ye Z, Zhu J, Zhang Y, Zhang Y. Predictors of acute compartment syndrome of the lower leg in adults following tibial plateau fractures. J Orthop Surg Res. 2021;16(1):502. https://doi.org/10.1186/s13018-021-02660-7. 6. Luo CF, Sun H, Zhang B, Zeng BF. Three-column fixation for complex tibial plateau fractures. J Orthop Trauma. 2010;24(11):683–92. https://doi.org/10.1097/BOT.0b013e3181d436f3. 7. Samsami S, Herrmann S, Pätzold R, Winkler M, Augat P. Finite element analysis of bi-condylar Tibial plateau fractures to assess the effect of coronal splits. Med Eng Phys. 2020;84:84–95. https://doi.org/10.1016/j.medengphy.2020.07.026. 8. Samsami S, Pätzold R, Winkler M, Herrmann S, Augat P. The effect of coronal splits on the structural stability of bi-condylar tibial plateau fractures: a biomechanical investigation. Arch Orthop Trauma Surg. 2020;140(11):1719–30. https://doi.org/10.1007/s00402-020-03412-8. 9. Dehoust J, Münch M, Seide K, Barth T, Frosch KH. Biomechanical aspects of the posteromedial split in bicondylar tibial plateau fractures-a finite-element investigation. Eur J Trauma Emerg Surg. 2020;46(6):1257–66. https://doi.org/10.1007/s00068-020-01538-3. 10. Giordano V, Kfuri M, Belangero W, Venturini A, Silva AC, Soares EM, Pires RE, Koch HA. Non-locked and locked small fragment straight plates have a similar behavior in buttressing the posteromedial shear tibial plateau fragment: a biomechanical analysis of three different fixations. J Exp Orthop. 2020;7(1):2. https://doi.org/10.1186/s40634-020-0218-0.

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11. Scotland T, Wardlaw D. The use of cast-bracing as treatment for fractures of the tibial plateau. J Bone Joint Surg Br. 1981;63B(4):575–8. https://doi.org/10.1302/0301-620X.63B4.7298688. 12. Delamarter R, Hohl M. The cast brace and tibial plateau fractures. Clin Orthop Relat Res. 1989;242:26–31. 13. Marwah V, Gadegone WM, Magarkar DS. The treatment of fractures of the tibial plateau by skeletal traction and early mobilisation. Int Orthop. 1985;9(4):217–21. https://doi.org/10.1007/ BF00266506. 14. Lee SM, Oh CW, Oh JK, Kim JW, Lee HJ, Chon CS, Lee BJ, Kyung HS. Biomechanical analysis of operative methods in the treatment of extra-articular fracture of the proximal tibia. Clin Orthop Surg. 2014;6(3):312–7. https://doi.org/10.4055/cios.2014.6.3.312. 15. Chen F, Huang X, Ya Y, Ma F, Qian Z, Shi J, Guo S, Yu B. Finite element analysis of intramedullary nailing and double locking plate for treating extra-articular proximal tibial fractures. J Orthop Surg Res. 2018;13(1):12. https://doi.org/10.1186/s13018-017-0707-8. 16. Scolaro JA, Wright DJ, Lai W, Fraipont G, Hitchens H, Kwak D, McGarry M, Lee TQ. Fixation of extra-articular proximal tibia fractures: biomechanical comparison of single and dual implant constructs. J Am Acad Orthop Surg. 2022;30(13):629–35. https://doi.org/10.5435/JAAOS-D21-01089. 17. Parker PJ, Tepper KB, Brumback RJ, Novak VP, Belkoff SM. Biomechanical comparison of fixation of type-I fractures of the lateral tibial plateau. Is the antiglide screw effective? J Bone Joint Surg Br. 1999;81(3):478–80. https://doi.org/10.1302/0301-620x.81b3.9100. 18. Koval KJ, Polatsch D, Kummer FJ, Cheng D, Zuckerman JD. Split fractures of the lateral tibial plateau: evaluation of three fixation methods. J Orthop Trauma. 1996;10(5):304–8. https://doi. org/10.1097/00005131-199607000-00003. 19. Jordan MC, Zimmermann C, Gho SA, Frey SP, Blunk T, Meffert RH, Hoelscher-Doht S. Biomechanical analysis of different osteosyntheses and the combination with bone substitute in tibial head depression fractures. BMC Musculoskelet Disord. 2016 Jul 15;17:287. https://doi. org/10.1186/s12891-016-1118-4. 20. Cross WW 3rd, Levy BA, Morgan JA, Armitage BM, Cole PA. Periarticular raft constructs and fracture stability in split-depression tibial plateau fractures. Injury. 2013;44(6):796–801. https:// doi.org/10.1016/j.injury.2012.12.028. 21. Patil S, Mahon A, Green S, McMurtry I, Port A. A biomechanical study comparing a raft of 3.5 mm cortical screws with 6.5 mm cancellous screws in depressed tibial plateau fractures. Knee. 2006;13(3):231–5. https://doi.org/10.1016/j.knee.2006.03.003. 22. Mayr R, Attal R, Zwierzina M, Blauth M, Schmoelz W. Effect of additional fixation in tibial plateau impression fractures treated with balloon reduction and cement augmentation. Clin Biomech. 2015;30(8):847–51. https://doi.org/10.1016/j.clinbiomech.2015.05.016. 23. Heilig P, Faerber LC, Paul MM, Kupczyk E, Meffert RH, Jordan MC, Hoelscher-Doht S. Plate osteosynthesis combined with bone cement provides the highest stability for tibial head depression fractures under high loading conditions. Sci Rep. 2022;12(1):15481. https://doi. org/10.1038/s41598-022-19107-6. 24. Wu CC, Tai CL. Plating treatment for tibial plateau fractures: a biomechanical comparison of buttress and tension band positions. Arch Orthop Trauma Surg. 2007;127(1):19–24. https://doi. org/10.1007/s00402-006-0192-8. 25. Cift H, Cetik O, Kalaycioglu B, Dirikoglu MH, Ozkan K, Eksioglu F. Biomechanical comparison of plate-screw and screw fixation in medial tibial plateau fractures (Schatzker 4). A model study. Orthop Traumatol Surg Res. 2010;96(3):263–7. https://doi.org/10.1016/j.otsr.2009. 11.016. 26. Huang X, Zhi Z, Yu B, Chen F. Stress and stability of plate-screw fixation and screw fixation in the treatment of Schatzker type IV medial tibial plateau fracture: a comparative finite element study. J Orthop Surg Res. 2015;10:182. https://doi.org/10.1186/s13018-015-0325-2. 27. Faur CI, Niculescu B. Comparative biomechanical analysis of three implants used in bicondylar tibial fractures. Wien Med Wochenschr. 2018;168(9–10):254–60. https://doi.org/10.1007/ s10354-017-0551-9.

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28. Hasan S, Ayalon OB, Yoon RS, Sood A, Militano U, Cavanaugh M, Liporace FA. A biomechanical comparison between locked 3.5-mm plates and 4.5-mm plates for the treatment of simple bicondylar tibial plateau fractures: is bigger necessarily better? J Orthop Traumatol. 2014;15(2):123–9. https://doi.org/10.1007/s10195-013-0275-6. 29. Higgins TF, Klatt J, Bachus KN. Biomechanical analysis of bicondylar tibial plateau fixation: how does lateral locking plate fixation compare to dual plate fixation? J Orthop Trauma. 2007;21(5):301–6. https://doi.org/10.1097/BOT.0b013e3180500359. 30. García Vélez DA, Headford M, Suresh KV, Liberatos PM, Bledsoe G, Revak T. Biomechanical analysis of dual versus lateral locked plating in elderly bicondylar tibial plateau fractures: does medial comminution matter? Injury. 2022;53(10):3109–14. https://doi.org/10.1016/j.injury. 2022.08.039. 31. Baumann P, Ebneter L, Giesinger K, Kuster MS. A triangular support screw improves stability for lateral locking plates in proximal tibial fractures with metaphyseal comminution: a biomechanical analysis. Arch Orthop Trauma Surg. 2011;131(6):815–21. https://doi.org/10.1007/ s00402-010-1243-8. 32. Yoo BJ, Beingessner DM, Barei DP. Stabilization of the posteromedial fragment in bicondylar tibial plateau fractures: a mechanical comparison of locking and nonlocking single and dual plating methods. J Trauma. 2010;69(1):148–55. https://doi.org/10.1097/TA. 0b013e3181e17060. 33. Ye X, Huang D, Perriman DM, Smith PN. Influence of screw to joint distance on articular subsidence in tibial-plateau fractures. ANZ J Surg. 2019;89(4):320–4. https://doi.org/10.1111/ ans.14978. 34. Metcalfe D, Hickson CJ, McKee L, Griffin XL. External versus internal fixation for bicondylar tibial plateau fractures: systematic review and meta-analysis. J Orthop Traumatol. 2015;16(4): 275–85. https://doi.org/10.1007/s10195-015-0372-9. 35. Kumar D, Sodavarapu P, Aggarwal A, Hooda A, Sajid M. Management and outcome of a complex medial tibial plateau fracture: a case report of a rare knee Varus injury variant. JBJS Case Connect. 2020;10(4):e19.00626. https://doi.org/10.2106/JBJS.CC.19.00626. 36. Cho JW, Samal P, Jeon YS, Oh CW, Oh JK. Rim plating of posterolateral fracture fragments (PLFs) through a modified anterolateral approach in tibial plateau fractures. J Orthop Trauma. 2016;30(11):e362–8. https://doi.org/10.1097/BOT.0000000000000638. 37. Giordano V, Schatzker J, Kfuri M. The “hoop” plate for posterior bicondylar shear tibial plateau fractures: description of a new surgical technique. J Knee Surg. 2017;30(6):509–13. https://doi. org/10.1055/s-0036-1593366. 38. Foos JK, Josifi E, Large TM. Supine posterior hoop plating of bicondylar posterior coronal shear tibial plateau fractures without fibular osteotomy. J Orthop Trauma. 2023;37(1):45–50. https://doi.org/10.1097/BOT.0000000000002420.

Implantology of Fractures of the Shaft of the Tibia Including Segmental Fractures

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Open Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External Fixation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tibia Interlocking Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Closed Fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conservative Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interlocking Nailing of the Tibia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Flexible Intramedullary Nailing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plating of the Tibia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Technical Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fulcrum Effect (Fig. 15) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bridge Plating of the Tibia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tibial Locked Internal Fixator Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Nowadays closed interlocking nailing is the gold standard of treatment in tibial shaft fractures. This includes segmental fractures. There are many types of tibial nailing possible – including those inserted by the infrapatellar and by the suprapatellar approaches. Various nails have different Herzog angles. Some have multidirectional locking options in the distal and proximal ends (such as the Synthes Expert Tibial Nail). However, conservative treatment and plating still have a limited role in certain cases such as fractures in the young and where there is relatively less displacement. A. K. Jha (*) Niramaya: Jha’s Superspeciality Centre for Orthopaedics, Dumdum, Kolkata, West Bengal, India

© Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_83

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External fixation has a limited role and is used when there is significant soft tissue compromise or in open fractures. Nailing is superior to other techniques due to better patient satisfaction, less time off work, and lower knee stiffness. Keywords

Tibial fracture · Implants · Interlocking nailing of the tibia · Tibial plating · Segmental fracture of the tibia

Introduction Tibia fractures are the most common long bone fractures and represent about 17% of all lower extremity fractures. Tibial fractures occur in a bimodal pattern involving both high- and low-energy mechanisms. Most of these fractures can be treated conservatively with predictable union rate; however, such treatment is prolonged and results in unsatisfactory outcome because of joint stiffness and prolonged absence from work. Certain fractures are predicted to do poorly with nonsurgical treatment like open fractures, highly comminuted or unstable fractures, tibial shaft fractures with intact fibula susceptible to varus malunion, tibial shaft fractures associated with ipsilateral femur fractures, intraarticular fractures at knee or ankle, unstable spiral fractures of the tibia associated with fibula fractures at a different level, etc. [1] Surgical options include open reduction followed by plate and screw fixation, minimally invasive plate osteosynthesis (MIPO) or percutaneous plating, intramedullary (IM) nailing, external fixation, and titanium elastic nailing of pediatric tibial shaft fractures. Segmental fractures of the tibia are difficult and challenging to manage. The incidence of tibial fractures being truly segmental ranges between 3% and 12%. These fractures are usually the result of high-energy trauma and hence are often associated with substantial soft tissues damage. Because of precarious vascularity of the middle segment and severely damaged surrounding soft tissue, high rates of delayed union, nonunion, compartment syndrome, septic complications, and poor outcome have been reported in segmental fractures as compared with nonsegmental fractures of the tibia [2]. These fractures need specialized treatment by experienced trauma surgeons in specialized centers and intramedullary nailing, preferably with a suprapatellar approach, should be considered as the primary option after properly informing patients about the high chances of complications.

Biomechanics The anatomy of the tibia and the fibula is illustrated in Fig. 1. It is important to know the anatomy of the tibia and the structures around it at different levels to understand implant fixation options and to deliver good functional outcomes after surgery. The tibial shaft is triangular in cross-section. The proximal medullary canal is centered laterally, hence the lateral starting point during intramedullary nailing. Proximal

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Fig. 1 Anatomy of the tibia and the fibula: (a) Tibial tuberosity, (b) interosseous membrane, (c) medial condyle of the tibia, (d) lateral condyle of the tibia, (e) medial malleolus, (f) lateral malleolus, (g) articular surface of the tibia, (h) distal tibiofibular joint, (i) head of fibula

tibiofibular joint is a gliding synovial joint and the tibia is responsible for about 80–85% of lower extremity weight-bearing. Interosseous membrane is a fibrous structure interconnecting the tibia and the fibula and provides axial stability. At the tibiofibular syndesmosis, the fibula rests in distal tibial incisura and is stabilized by the syndesmotic ligaments – the anterior inferior tibiofibular ligament (AITFL), the posterior inferior tibiofibular ligament (PITFL), the inferior transverse tibiofibular ligament (ITL), and the interosseous ligament (IOL), which is a continuation of the interosseous membrane. Syndesmotic stability can be affected by distal, spiral tibial shaft fractures. Various options exist for the management of fractures of the shaft of the tibia including the segmental ones. These are being discussed in the following sections:

Open Fractures External Fixation This can be used as temporary fixation measure in the case of open fractures until wound healing is seen satisfactorily. Minimal internal implants such as Kirschner wires (K-wires) and cortical screws have been recommended to improve the

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performance of external fixation, however with increased chances of infection [3]. In fractures with delay in initial debridement of more than 8 h, staged nailing should be done, external fixation being applied in stage one. After a certain time, usually around 2 weeks, the external fixator is removed and definitive fixation is done. The chances of infection are higher if the external fixator pins have been in place for more than 2 weeks before reamed tibial nailing. External fixator may be applied as a permanent definitive treatment for some open fractures where the wound is grossly contaminated and the chances of wound healing are remote. Chances of nonunion are high in such injuries. The important indications of external fixation are as follows: • • • •

Damage control orthopedics in polytrauma patients Open tibia fractures Associated vascular injuries requiring revascularization Segmental or significantly comminuted fractures

Tibia Interlocking Nailing In grade I, II, and some tidy grade III open fractures, interlocking nailing is done as definitive surgery. If initial debridement is adequate and timely, definitive stabilization by reamed intramedullary tibial nailing can be done. In open fractures, use of a solid nail avoids large dead space present in a tubular nail where infection could flourish. A thinner, solid unreamed interlocking nail provides stability similar to that of a reamed nail and so may be an alternative to external fixation in open fractures, although the possibility of increased chances of infection is a concern.

Plating Surface implants as definitive surgery is usually avoided in open fractures. New implant designs and development of less traumatic techniques for plating have opened up some scope for plating in noncontaminated open tibial fractures along with concurrent use of elaborate techniques of early and adequate soft tissue coverage by the plastic surgery team [4].

Closed Fractures Conservative Treatment Conservative treatment is recommended for undisplaced or minimally displaced tibia shaft fractures. Displaced fractures that can be reduced and maintain acceptable alignment like simple transverse or oblique fractures especially with intact fibula can

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also be treated conservatively. The conservative treatment in tibia fractures is acceptable when the following criteria are met after reduction: [5]. • • • • • •

4 mm 3.5 mm Relative sagittal rotation >11
Positive stretch test Spinal cord injury Nerve root injury Disc narrowing (abnormal) Anticipated dangerous load

Pointsa 2 2 2 2 2 2 1 1 1

Unstable if total score > 5

different direction) [49]. The vector forces may be in flexion, extension, compression, or lateral bending.

Cervical Kinematics After Motion Preserving Surgery Laminoplasty Cervical laminoplasty is a non-fusion, decompression procedure of the spinal cord in a patient with cervical myelopathy [50]. The two most popular laminoplasty techniques are “open door laminoplasty” (ODL) and “French door laminoplasty” (FDL). These procedures are similar to a “door hinge” where one side of the lamina is kept intact and hinges on the contralateral side [50]. It is observed that the amount of canal expansion was higher with ODL [51]. ODL resulted in a higher functional outcome and recovery rate [50]. Laminoplasty can be performed over two to six (C2–C6) cervical levels according to the degree of involvement. There was no change in cervical ROM between the non-operated and laminoplasty spines (even if multiple-level laminoplasty was performed). Therefore, extension of laminoplasty to adjacent levels does not affect stability unless the facet joints are removed [52]. In a study, post-laminoplasty segmental cervical ROM was analysed using lateral radiographs. It was observed that cervical ROM at all cervical levels decreased significantly, except at C2–C3 and C7–T1 after a mean of 6 years [53]. Takeuchi et al. reported that axial rotation is much preserved if the semispinalis cervicis insertion is preserved during laminoplasty [54]. Nagamoto et al. used functional CT scan to describe ROM between C0–T1 in flexion–extension as well as rotation and found that C0–T1 ROM did not change significantly at 6 months follow-up [55].

Cervical Disc Arthroplasty (CDA) Cervical disc arthroplasty (CDA) preserves the segmental motion, restores the sagittal balance, and simulates natural kinematics of cervical spine, thus preventing adjacent segment disease (Fig. 9 a & b). Normal motion between two vertebrae

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Fig. 9 (a) AP radiograph of a 56-year-old female showing C5/6 cervical disc arthroplasty (CDA). (b, c) Lateral radiographs in flexion and extension showing the mobility of the CDA at C5/6

occurs around the COR. CDA devices attempt to maintain the COR of the normal spine [56], thus reproducing normal kinematics. An artificial disc could restore disc height and preserve the dynamic function of the involved cervical level. CDA allows patients to quickly return to routine activities. CDA has been shown to maintain the normal motion at the adjacent levels. Ideally the intervertebral motion following CDA should not be more than 11
difference in the range of motion between adjacent levels [57]. Following CDA, computational model analysis of disc stresses at the adjacent levels showed similar trends as motion. Analysis of facet forces at the index and adjacent levels suggested that facet forces increased to a great extent at the index level but decreased facet forces at the adjacent levels. On the contrary, facet forces are increased in cervical fusion [58]. In contrast, operated-level ROM was preserved with single- and two-level CDA under all loading conditions [59].

Biomechanics of Anterior Cervical Spinal Fusion (ACDF) In cervical fusion surgery, the goal is to minimize motion and achieve solid union between two vertebrae. ACDF (anterior cervical decompression and fusion) has been the gold standard treatment for cervical spondylosis with radiculopathy or myelopathy in patients with failed conservative management [60]. ACDF and ACCF (anterior cervical corpectomy and fusion) is favoured when a patient has kyphosis and neck pain with MRI confirmation of prolapsed disc herniation involving one or two levels [61]. Biomechanical analysis of single-level C5/6 fusion suggested that anterior cervical plate has a positive impact on the stress distribution at vertebrae and the bone graft. When the plate is used with a cage, the stress on the graft is further decreased [62]. Both the procedures (ACDF and ACCF) have proven to be reliable and effective in achieving a good clinical outcome. Biomechanical FEA analysis suggested that ACDF decreases the cage subsidence risk due to reduced stress on the end plates, while the ACCF induces increased stress on the bone graft and reduced stress on the fixation system, thereby benefiting bone fusion and long-term spinal stability [63].

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Studies comparing titanium versus PEEK cages suggested similar fusion rates, but rate of subsidence was increased with titanium cages [64]. Research on the immediate kinematic performance of locking and rotational plates suggest no significant differences when applied in two-level ACDF. But the rotational plate causes greater reduction in motion in lateral bending and axial rotation [65].

Biomechanical Comparisons Between Surgical Techniques CDA Versus ACDF CDA avoids the complications of anterior cervical plating, that is, pseudoarthrosis. Anderson et al. (2012) observed no significant difference in the ROM (both clinically and statistically) in the adjacent segment or COR after CDA as compared with ACDF. They also observed that the adjacent segments were more lordotic after CDA and higher angular ROM change after CDA [66]. A kinematic analysis compared one-level ACDF, one-level CDA, and an intact spine using porous-coated motion device (PCM). The analysis suggested increase of ROM at the adjacent level in ACDF group by 33%. The CDA group and intact spine had similar ROM in all direction. The CDA group’s COR closely mimicked the intact spine group [59]. Similar reliability has been observed for CDA and ACDF in providing relief from cervical disc disease in short- and mid-term outcome studies [67]. Fewer reoperations were required in CDA as compared to ACDF, suggesting CDA to be a safe and effective alternative to fusion for cervical radiculopathy and myelopathy [68].

Hybrid Surgery Hybrid surgery (HS) involves the combination of ACDF and CDA. This technique is increasingly used for patients with multi-level cervical degenerative disc disease (DDD). The combination of fusion and non-fusion technology can be tailored to the requirement. This combination allows for preservation of segmental motion at the index levels and minimizes adjacent levels’ hypermobility. A meta-analysis of HS technique has shown a clear advantage for motion preservation at the index levels and had less adverse effects at adjacent levels compared with ACDF or CDA alone [69].

MIS Fusion Versus ACDF Minimally invasive posterior cervical foraminotomy (MI-PCF) and percutaneous full-endoscopic anterior cervical discectomy (PEACD) have been increasingly used

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in the current years for treatment of cervical spondylotic radiculopathy (CSR). Finite element models of PEACD, PCF, and ACDF suggested that from a biomechanical point of view, PCF and PEACD were more suitable for surgical intervention for CSR than ACDF [70].

Summary It is difficult to simulate physiological loading and evaluate treatment of spine owing to its complex nature. Motion preservation devices allow motion and stability to the whole FSU, but we as clinicians require a means to biomechanically evaluate the potential for such treatments at the index and adjacent levels. Parameters for motion preservation devices should include parameters for quality of motion. High-quality imaging studies should be used for successful outcome studies in cervical spine for either motion preserving or fusion.

References 1. Sarig Bahat H, Weiss PL, Laufer Y. The effect of neck pain on cervical kinematics, as assessed in a virtual environment. Arch Phys Med Rehabil. 2010;91:1884–90. 2. Bovim G, Schrader H, Sand T. Neck pain in the general population. Spine (Phila Pa 1976). 1994;19:1307–9. 3. Cote P, Cassidy JD, Carroll LJ, et al. The annual incidence and course of neck pain in the general population: a population-based cohort study. Pain. 2004;112:267–73. 4. Panjabi MM, Dutancaeau J, Goel V, et al. Cervical human vertebrae. Quantitative three dimensional anatomy of the middle and lower regions. Spine (Phila Pa 1976). 1991;16:861–9. 5. Ng HW, Teo EC, Lee KK, Qiu TX. Finite element analysis of cervical spinal instability under physiologic loading. J Spinal Disord Tech. 2003;16(1):55–65. 6. Oda T, Panjabi MM, Crisco JJIII, Oxland TR, Katz L, Nolte LP. Experimental study of atlas injuries. II. Relevance to clinical diagnosis and treatment. Spine (Phila Pa 1976). 1991;16 (10 Suppl):S466–73. 7. Lopez AJ, Scheer JK, Leibl KE, Smith ZA, Dlouhy BJ, Dahdaleh NS. Anatomy and biomechanics of the craniovertebral junction. Neurosurg Focus. 2015;38(4):1–8. 8. Clark CR, White AAIII. Fractures of the dens. A multicenter study. J Bone Joint Surg Am. 1985;67:1340–8. 9. Dvorak J, Schneider E, Saldinger P, Rahn B. Biomechanics of the craniocervical region: the alar and transverse ligaments. J Orthop Res. 1988;6:452–61. 10. Tubbs RS, Kelly DR, Humphrey ER, Chua GD, Shoja MM, Salter EG, et al. The tectorial membrane: anatomical, biomechanical, and histological analysis. Clin Anat. 2007;20:382–6. 11. Parke WW. The vascular relations of the upper cervical vertebrae. Orthop Clin North Am. 1978;9:879–89. 12. Panjabi M, Dvorak J, Duranceau J, Yamamoto I, Gerber M, Rauschning W, et al. Threedimensional movements of the upper cervical spine. Spine. (Phila Pa1976). 1988;13:726–30. 13. Tubbs RS, Hallock JD, Radcliff V, et al. Ligaments of the craniocervical junction. J Neurosurg Spine. 2011;14:697–709. 14. Debernardi A, D’Aliberti G, Talamonti G, Villa F, Piparo M, Collice M. The craniovertebral junction area and the role of the ligaments and membranes. Neurosurgery. 2011;68(2):291–301. 15. Goel V, Clark C, Gallaes K, Liu Y. Moment-rotation relationships of the ligamentous occipitoatlanto-axial complex. J Biomech. 1988;21(8):673–80.

1850

U. K. Debnath

16. Dvorak J, Panjabi M, Novotny J, Antinnes J. In vivo flexion/extension of the normal cervical spine. J Orthop Res. 1991;9(6):828–34. 17. Iai H, Moriya H, Goto S, Takahashi K, Tamaki T. Three-dimensional motion analysis of the upper cervical spine during axial rotation. Spine, (Phila Pa 1976). 1993;18(16):2388–92. 18. Wolfla CE. Anatomical, biomechanical, and practical considerations in posterior occipitocervical instrumentation. Spine J. 2006;6(1):S225–32. 19. Panjabi M, Dvorak J, Crisco JJIII, et al. Effects of alar ligament transection on upper cervical spine rotation. J Orthop Res. 1991;9:584–93. 20. Ochalski PG, Spiro RM, Fabio A, Kassam AB, Okonkwo DO. Fractures of the clivus: a contemporary series in the computed tomography era. Neurosurgery. 2009;65(6):1063–9. 21. Chaput CD, Walgama J, Torres E, Dominguez D, Hanson J, Song J, et al. Defining and detecting missed ligamentous injuries of the occipitocervical complex. Spine (Phila Pa 1976). 2011;36(9): 709–14. 22. Alcelik I, Manik KS, Sian PS, Khoshneviszadeh SE. Occipital condylar fractures. Review of the literature and case report. J Bone Joint Surg (Br). 2006;88(5):665–9. 23. Anderson PA, Montesano PX. Morphology and treatment of occipital condyle fractures. Spine (Phila Pa 1976). 1988;13(7):731–6. 24. Vishteh A, Crawford N, Melton M, Spetzler R, Sonntag V, Dickman CA. Stability of the craniovertebral junction after unilateral occipital condyle resection: a biomechanical study. J Neurosurg Spine. 1990;90(1):91–8. 25. Clark JG, Abdullah KG, Mroz TE, Steinmetz MP. Biomechanics of the craniovertebral junction. In: Klika V, editor. Biomechanics in applications. IntechOpen. 2011;p. 189–204. https://doi.org/ 10.5772/21253. 26. Anderson LD, D’Alonzo RT. Fractures of the odontoid process of the axis. J Bone Joint Surg Am. 1974;56(8):1663–74. 27. Dickman CA, Crawford NR, Brantley AG, et al. Biomechanical effects of transoral odontoidectomy. Neurosurgery. 1995;36:1146–52. 28. Dickman CA, Lekovic CV. Biomechanical considerations for stabilization of the craniovertebral junction. Clin Neurosurg. 2005;52:205–13. 29. Lee C, Woodring JH. Unstable Jefferson variant atlas fractures: an unrecognized cervical injury. AJNR Am J Neuroradiol. 1991;12(6):1105–10. 30. Greene KA, Dickman CA, Marciano FF, Drabier JB, Hadley MN, Sonntag VK. Acute axis fractures. Analysis of management and outcome in 340 consecutive cases. Spine (Phila Pa 1976). 1997;22(16):1843–52. 31. Mead LB II, Millhouse PW, Krystal J, Vaccaro AR. C1 fractures: a review of diagnoses, management options, and outcomes. Curr Rev Musculoskelet Med. 2016;9:255–62. 32. Pan J, Huang D, Hao D, et al. Occipitocervical fusion: fix to C2 or C3? Clin Neurol Neurosurg. 2014;127:134–9. 33. Bosco A, Aleem I, La Marca F. Occipital condyle screws: indications and technique. J Spine Surg. 2020;6(1):156–63. 34. Helgeson MD, Lehman RA, Sasso RC, Dmitriev AE, Mack AW, Riew KD. Biomechanical analysis of occipitocervical stability afforded by three fixation techniques. Spine J. 2011;11(3): 245–50. 35. Hurlbert RJ, Crawford NR, Choi WG, et al. A biomechanical evaluation of occipitocervical instrumentation: screw compared with wire fixation. J Neurosurg Spine. 1999;90:84–90. 36. Oda I, Abumi K, Sell LC, et al. Biomechanical evaluation of five different occipito-atlanto-axial fixation techniques. Spine (Phila Pa 1976). 1999;24:2377–82. 37. Lehman RAJ, Dmitriev AE, Wilson KW. Biomechanical analysis of the C2 intralaminar fixation technique using a cross-link and offset connector for an unstable atlantoaxial joint. Spine J. 2012;12:151–6. 38. Uribe JS, Ramos E, Youssef AS, et al. Craniocervical fixation with occipital condyle screws: biomechanical analysis of a novel technique. Spine (Phila Pa 1976). 2010;35:931–8.

100

Biomechanics of the Cervical Spine

1851

39. Mestdagh H. Morphological aspects and biomechanical properties of the vertebroaxial joint (C2–C3). Acta Morphol Neerl Scand. 1976;14(1):19–30. 40. Duggal N, Chamberlain RH, Perez-Garza LE, Espinoza-Larios A, Sonntag VKH, Crawford NR. Hangman’s fracture: a biomechanical comparison of stabilization techniques. Spine (Phila Pa 1976). 2007;32:182–7. 41. Park JH, Kim SH, Cho KH. Clinical outcomes of posterior C2–C3 fixation for unstable Hangman’s fracture compared with posterior C1–C3 fusion. Korean J Spine. 2014;11(2): 33–8. 42. Panjabi MM, Lydon C, Vasavada A, Grob D, Crisco JJ, Dvorak J. On the understanding of clinical instability. Spine (Phila Pa 1976). 1994;23:2642–50. 43. Olson KA, Joder D. Diagnosis and treatment of cervical spine clinical instability. J Orthop Sports Phys Ther. 2001;31(4):194–206. 44. Van Mameren H, Drukker J, Sanches H, Beursgens J. Cervical spine motion in the sagittal plane (I) range of motion of actually performed movements, an X-ray cinematographic study. Eur J Morphol. 1990;28:47–68. 45. Swartz EE, Floyd RT, Cendoma M. Cervical spine functional anatomy and the biomechanics of injury due to compressive loading. J Athl Train. 2005;40(3):155–61. 46. Nightingale RW, McElhaney JH, Richardson WJ, Myers BS. Dynamic responses of the head and cervical spine to axial impact loading. J Biomech. 1996;29:307–18. 47. Penning L. Kinematics of cervical spine injury: a functional radiological hypothesis. Eur Spine J. 1995;4:126–32. 48. Oxland TR, Panjabi MM. The onset and progression of spinal injury: a demonstration of neutral zone sensitivity. J Biomech. 1992;25:1165–72. 49. Van Toen CY. Biomechanics of cervical spine and spinal cord injury under combined axial compression and lateral bending loading. Thesis for Univ of British Columbia, Vancouver. (2013). https://doi.org/10.14288/1.0072137. 50. Wiguna GLNAA, Magetsari R, Noor Z, Suyitno S, Nindrea RD. Comparative effectiveness and functional outcome of open-door versus French-door laminoplasty for multilevel cervical myelopathy: a meta-analysis. Open Access Maced J Med Sci. 2019;7(19):3348–52. 51. Luo W, Li Y, Zhao J, Gu R, Jiang R, Lin F. Open-versus French-door laminoplasty for the treatment of cervical multilevel compressive myelopathy: a meta-analysis. World Neurosurg. 2018;117:129–36. 52. Puttlitz CM, Deviren V, Smith JA, Kleinstueck FS, Tran QNH, Thurlow RW, et al. Biomechanics of cervical laminoplasty: kinetic studies comparing different surgical techniques, temporal effects and the degree of level involvement. Euro Spine J. 2004;13(3):213–21. 53. Baba H, Maezawa Y, Furusawa N, Imura S, Tomita K. Flexibility and alignment of the cervical spine after laminoplasty for spondylotic myelopathy. A radiographic study. Int Orthop. 1995;19: 116–21. 54. Nagamoto Y, Iwasaki M, Sugiura T, Fujimori T, Matsuo Y, Kashii M, et al. In vivo 3D kinematic changes in the cervical spine after laminoplasty for cervical spondylotic myelopathy. J Neurosurg Spine. 21:417–24. 55. Takeuchi K, Yokoyama T, Ono A, Numasawa T, Wada K, Kumagai G, et al. Limitations of activities of daily living accompanying reduced neck mobility after cervical laminoplasty. Arch Orthop Trauma Surg. 2007;127:475–80. 56. Aleksanderek I, Lazaro BCR, Fink M, Robin D, Dugal N. Analysis of in vivo kinematics of 3 different cervical devices: Bryan disc, ProDisc-C, and Prestige LP disc. J Neurosurg Spine. 2011;15(6):630–5. 57. Reitman CA, Mauro KM, Nguyen L. Intervertebral motion between flexion and extension in asymptomatic individuals. Spine. 2004;24:2832–43. 58. Gandhi AA, Kode S, DeVries NA. Biomechanical analysis of cervical disc replacement and fusion using single level, two level and hybrid constructs. Spine (Phila Pa 1976). 2015;40: 1578–85. https://doi.org/10.1097/BRS.0000000000001044.

1852

U. K. Debnath

59. Cunningham BW, Hu N, Zorn CM, McAfee PC. Biomechanical comparison of single- and two level cervical arthroplasty versus arthrodesis: effect on adjacent – level spinal kinematics. Spine J. 2010;10(4):341–9. 60. Gore DR, Sepic SB. Anterior discectomy and fusion for painful cervical disc disease: a report of 50 patients with an average follow-up of 21 years. Spine (Phila Pa 1976). 1998;23:2047–51. 61. Li JF, Zheng QX, Guo XD, et al. Anterior surgical options for the treatment of cervical spondylotic myelopathy in a long-term follow-up study. Arch Orthop Trauma Surg. 2013;133(6):745–51. 62. Fernandes PC, Fernandes PR, Folgado JO, Levy Melancia J. Biomechanical analysis of the anterior cervical fusion. Comput Methods Biomech Biomed Eng. 2012;15(12):1337–46. 63. Ouyang P, Li J, He X, Dong H, Zang Q, et al. Biomechanical comparison of 1-level corpectomy and 2-level discectomy for cervical spondylotic myelopathy: a finite element analysis. Med Sci Monit. 2020;26:e919270-1–e919270-11. 64. Seaman S, Kerezoudis P, Bydon M, Torner JC, Hitchon PW. Titanium vs. polyetheretherketone (PEEK) interbody fusion: meta-analysis and review of the literature. J Clin Neurosci. 2017;44: 23–9. 65. Tsitsopoulos PP, Voronov LI, Zindrick MR, Carandag G, Havey RM, et al. Biomechanical stability analysis of a stand-alone cage, static and rotational-dynamic plate in a two-level cervical fusion construct. Orthop Surg. 2017;9(3):290–5. 66. Anderson PA, Sasso RC, Hipp J, Norvell DC, Raich A, Hashimoto R. Kinematics of the cervical adjacent segments after disc arthroplasty compared with anterior discectomy and fusion: a systematic review and meta-analysis. Spine (Phila PA 1976). 2012;37(22 Suppl):S85–95. 67. Pisano A, Helgeson M. Cervical disc replacement surgery: biomechanical properties, postoperative motion, and postoperative activity levels. Curr Rev Musculoskelet Med. 2017;10: 177–81. 68. Zhong ZM, Zhu AY, Zhuang JS, Wu Q, Chen JT. Reoperation after cervical disc arthroplasty versus anterior cervical discectomy and fusion: a meta-analysis. Clin Orthop Relat Res. 2016;474(5):1307–16. 69. Jia Z, Mo Z, Ding F, He Q, Fan Y, Ruan D. Hybrid surgery for multilevel cervical degenerative disc diseases: a systematic review of biomechanical and clinical evidence. Eur Spine J. 2014;23: 1619–32. https://doi.org/10.1007/s00586-014-3389-5. 70. Chen C, Yuchi CX, Gao Z, Ma X, Zhao D, et al. Comparative analysis of the biomechanics of the adjacent segments after minimally invasive cervical surgeries versus anterior cervical discectomy and fusion: a finite element study. J Orthop Translat. 2020;23:107–12. 71. Smit TH, van Tunen MS, van der Veen AJ, Kingma I, van Dieën JH. Quantifying intervertebral disc mechanics: a new definition of the neutral zone. BMC Musculoskelet Disord. 2011;12:38. https://doi.org/10.1186/1471-2474-12-38. PMID: 21299900; PMCID: PMC3041726 72. Guo Z, Cui W, Sang DC, Sang HP, Liu BG. Clinical relevance of cervical kinematic quality parameters in planar movement. Orthop Surg. 2019;11(2):167–75. https://doi.org/10.1111/os. 12435. Epub 2019 Mar 18. PMID: 30884156; PMCID: PMC6594496 73. White AA III, Panjabi MM. Clinical Biomechanics of the Spine, 2nd ed. Baltimore, MD: Lippincott Williams & Wilkins; 1990. 74. Dvorak J, Froehlich D, Penning L, Baumgartner H, Panjabi MM. Functional radiographic diagnosis of the cervical spine: flexion/extension. Spine. 1988;13:748–755. 75. Penning L. Normal movement of the cervical spine. Am J Roentgenol. 1978;130:317–26. 76. Dvorak J, Panjabi MM, Gerber M, Wichman W. CT-functional diagnostics of the rotatory instability of the upper cervical spine. Spine. 1987;12:197–205. 77. White AA III, Panjabi MM. Update on the evaluation of instability of the lower cervical spine. Instr Course Lect 1987;36:513.

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Ahmad Hammad, Vijay Goel, and Alaaeldin A. Ahmad

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thoracic Spine As an Integrated System (Vertebral and Costal) . . . . . . . . . . . . . . . . . . . . . . . . . . Thoracic Spine As a Couple Between Cervical and Lumbar Spine: Thoracic Kyphosis . . . Anatomical Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thoracic Intervertebral (IV) Disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Functional Thoracic Spine Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Physical Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Basic Mechanisms of Load Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influence of Ageing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influence of Injury or Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influence of Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influence of Implants on Thoracic Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedicle Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sublaminar Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intervertebral Cages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Implants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rod-Hook Construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Long vs Short Fixation Construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Implant Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedicle Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sublaminar Wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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A. Hammad American University of Beirut, Beirut, Lebanon e-mail: [email protected] V. Goel Engineering Center for Orthopedic Research Excellence (E-CORE), University of Toledo, Toledo, OH, USA e-mail: [email protected] A. A. Ahmad (*) Pediatric orthopedic, Annajah Medical School, Nablus, Palestine © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_114

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Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1867 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1868

Abstract

The thoracic spine is the largest segment of the spinal column and is comprised of 12 vertebrae. It confers immense stability to the entire spine being an integrated unit between a vertebral system and a costal system. The functional spinal unit is the smallest functional motion spinal segment and is characterized by a neutral and an elastic zone that dictate spinal stability and stiffness, respectively. Several spinal fixation devices were introduced that aim at creating a rigid construct with the spine, a construct that maintains position, provides stabilization, and restores alignment. Spinal hardware may fail due to incorrect selection/placement or from migration, dislodgment, or implant failure with time. Keywords

Thoracic spine · Thoracic kyphosis · Functional thoracic spine unit · Pedicle instrumentation · Sublaminar wiring · Expandable corpectomy cage · Titanium mesh cage · 3D printed titanium vertebral body replacement · Implant failure

Introduction Thoracic Spine As an Integrated System (Vertebral and Costal) The thoracic spine is the portion of the spine found in the upper back. It starts at the neck base and ends at the bottom of the rib cage. It comprises 12 vertebrae labeled T1 to T12 and is considered to be the largest segment of the spinal column. The thoracic spine is unique because it is an integrated unit between two skeletal systems: a vertebral system and a costal system. The immense stability this combination confers to the thoracic spine has led some doctors and researchers to propose the addition of a “fourth column” to the classic three-column model of spinal stability with the rib cage and sternum being the core elements of the additional column. The vertebral body is the major load-bearing structure of the functional spinal unit (FSU) and acts as a buttress to compressive forces. Each vertebral body consists of an external cortical bone and an inner cancellous bone. The cortical bone is thin yet strong to resist torsion and bending, whereas the inner spongy matrix of the cancellous bone confers more elasticity, which maintains the shape of the bone during compression. Several features distinguish the thoracic vertebrae from other spinal segments. One feature is the presence of facets on vertebral body sides; these costal facets are smooth, small, and somewhat concave for ribs attachment. There are transverse processes that are thick, strong, and have a clubbed end with a small concave surface for vertebral articulation with the rib tubercle. For each of the 12 thoracic vertebrae, there is a corresponding pair of ribs attached to them through the costovertebral and costotransverse joints that

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distinguish thoracic from the cervical and lumbar spine. The costovertebral and costotransverse articulations occur from the 1st to 10th thoracic vertebrae and contribute to upper thoracic spine stability. The ribs articulate with the thoracic disc at the costovertebral joint, and with the transverse process at the costotransverse articulation. In a series of cadaveric sectioning study, it was found that ribs add stiffness to rotational and bending forces to the thoracic spine. The rib cage contributes to increased stability of the thoracic spine in flexion/extension (40%), lateral bending (35%), and axial rotation (31%) [1, 2]. The ribs accounted for 78% of mechanical thoracic stability and when the rib head is resected, ROM is increased from 70% to 80% in flexion, extension, and bending. In addition to stabilizing the thoracic spine in the mid-thoracic portion, the rib cage allows flexible transitions in the inferior and superior directions toward the lumbar and cervical spinal segments [3].

Thoracic Spine As a Couple Between Cervical and Lumbar Spine: Thoracic Kyphosis The human vertebral column is composed of a set of natural reciprocal curves that divide the spine into four distinct regions: cervical, thoracic, lumbar, and sacropelvic. These curves are responsible for the normal posture of the spine at rest or in a neutral position. The spine has characteristic radiographic alignment that manifests as straight when viewed in the coronal (frontal) plane but curved in the sagittal (lateral) plane; cervical and lumbar segments exhibit natural whereas thoracic and sacrococcygeal segments display natural kyphosis. These curves are thought to increase shock absorption and improve resistance to vertical loads. When the natural curvatures are maintained, compressive forces could be shared by the tension produced from stretching of muscles and connective tissues located on the side of each curve. It is interesting to note also that the important vital organs within the chest and pelvis lie within a space provided by the anterior concavity of the thoracic and sacral segments of the spine. The thoracic vertebral body height tends to increase posteriorly, which yields the physiologic thoracic kyphosis (TK). The customary definition of TK was the angle between T4 and T12 and measured to be between 10 and 40 [4]. A study to understand thoracic morphology, shape, and proportionality and analyse thoracic kyphosis by measuring kyphosis at T1–T12, T4–T12, and so forth [5]. T1–T12 contributes to more than 90% of the maximum TK and thus is more descriptive of TK than T4–T12, which seemingly underestimates the maximum whole spine kyphosis by 20%. When vertebral orientation was analysed, L1 was the most posteriorly tilted vertebra with a tilt of 20  8.2 whereas T7 was the least tilted (most horizontal). T7 represented the apex of kyphosis with a tilt of 0.1  7.4 . On further analysis, the most anteriorly tilted vertebra was T1 and the most stable vertebra was T9 (tilt of 10.8  6.9 ). TK and proportionality were found to be significantly correlated, i.e., as the TK increased, the portion of the thoracic curvature coming from above decreased and TK becomes more symmetric.

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Anatomical Differences One of the hallmarks of the thoracic spine is the physiological kyphotic sagittal alignment in the upper thoracic spine, which transitions through the relatively neutral thoracolumbar junction to reach the lordotic lumbar spine. As the thoracic spine matures, the superior costovertebral joint limits the degree of the rotation in all planes, while in old age, the ossification of the costal cartilages decreases the pliability of thorax relative flexibility [6]. Therefore, three spinal conditions are identified; first of which is the “mobile thorax” where the rib cage appears to be more mobile than thoracic spine. The second of which is the “stiff thorax” whereby the thoracic spine is more mobile than the rib cage. The third condition involves the same relative flexibility between thoracic spine and the rib cage [7]. Furthermore, the differences in the biomechanical behavior correlating with the anatomical differences between the segments dictate the following four regions in the thoracic spine.

Vertebromanubrial – Includes the first two thoracic vertebrae, 1st and 2nd ribs and the manubrium. – T1 is the transitional vertebrae, which shares characteristics with the cervical spine. Due to the reduced relative mobility of the first 2 ribs, the movement pattern at the vertebromanubrial region is similar to the “stiff thorax” pattern. Vertebrosternal – Includes vertebrae T3 to T6, third to sixth ribs and the sternum. – Typical thoracic vertebra with heart-shaped vertebral bodies, demifacets for the head of the ribs and transverse processes project posteriorly as well as laterally. Vertebrochondral – Includes T7–T10 vertebrae with the 7th–10th ribs. – T10 vertebral body articulates with the 10th rib only. Anteriorly, and through series of cartilaginous bars, ribs 8, 9, and 10 indirectly articulate with the sternum. Thoracolumbar – Includes vertebrae T11 and T12 and the 11th and 12th ribs – Ribs 11 and 12 are disconnected from the sternum and are called “floating ribs”. – T12 also has only one facet on each side. Being part of the transition to the lower back, this vertebra tends to have characteristics similar to those of the lumbar spine.

Thoracic Intervertebral (IV) Disc The intervertebral disc accounts for one-fifth of thoracic spinal length as reported by Aeby and colleagues [8]. The junction of two consecutive vertebral bodies and the intermediary IV disc form the interbody joint. The outer layer of the disc called the

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annulus fibrosus primarily withstands compression and allows bending movements. Enclosed within the annulus fibrosis is the nucleus pulposus, which is a gelatinous matrix that expands outward during compression thus increasing tension and stiffness, and rendering the systemic a dynamic one. Fluid flow in the IV disc follows a diurnal rhythm. During daytime, mechanical loading leads to increase in intradiscal pressure, expelling water from the disc, and the disc height is lost. Inversely, during unloading in supine position at night, the swelling pressure attracts fluid into the disc, increasing its height. The IV disc has a uniform thickness along the entire thoracic spine; however, both width and height of the disc increase as one progresses caudally down the thoracic spine corresponding with the increase in vertebral body size [9]. IV disc plays a large role in thoracic spine stability. IV disc degeneration leads to decreased range of motion in flexion/extension and lateral bending. The thoracic spine kinematics is determined by its own mechanical properties, morphology, and grade of degeneration of IV disc.

Functional Thoracic Spine Unit The smallest functional motion spinal segment is referred to as the functional spinal unit (FSU), which involves two adjacent vertebrae and the surrounding soft tissues. The facet joints fit between vertebrae allowing for movement and forming a neural foramen between the vertebrae, a space through which nerve roots travel. An FSU model allows for translation and/or rotation of the spine around three orthogonal axes, i.e., 12 of freedom which when combined facilitate more complex motions of flexion, extension, axial rotation, and lateral bending. Physiological spinal range of motion (ROM) demonstrates biphasic non-linear load displacement behavior, characterized by a neutral zone (NZ) and an elastic zone (EZ) [9, 10].

Physical Properties Spinal Stability: Neutral Zone and Soft Tissues The spinal column is unique in its ability to support bodily movements while maintaining structural stability and protecting neurovascular structures [10]. The physiologic spinal motion is naturally produced at minimal internal resistance. The intervertebral range at which such motion is produced is, and as described by Panjaib, a zone of high flexibility or laxity called the NZ. Muscle strengthening, osteophyte formation, and surgical fixation, or fusion surgery tend to decrease the NZ within a normal physiological range [9, 10]. Six human thoracic spinal motion segments from three segmental levels were analysed in an in vitro study [11]. Significant increases in the ROM were detected after resecting the anterior spinal ligaments with highest increases noticed after nucleotomy in all directions of motion. This study concluded that annulus fibrosis defines motion characteristics qualitatively. The annulus and ligaments restrict

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thoracic spinal segments’ mobility solely quantitatively and posterior ligament complex predominantly prevent hyperflexion [12]. Posterior element stability was crucial for the stability of the spine as previously described by Holdsworth in his “two-column theory”. Denis then proposed a novel element to classify thoracolumbar injuries, i.e., the “middle column”. As such, the anterior column consists of ALL (anterior longintudinal ligament) and ventral half of the vertebral body whereas the posterior column comprises of posterior elements and ligamentous structures. The middle column is made up of PLL (posterior longitudinal ligament), posterior annulus, and dorsal half of the vertebral column [13]. Henceforth, the integrity of the sternal complex is assumed to be an important contributing factor and a determinant of thoracic spinal stability especially in the transverse plane. The destabilizing impact of rib head release was more pronounced in the upper and middle segments of the thoracic spine compared to lower segments.

Stiffness: Elastic Zone, Tensile, and Compressive Stiffness EZ is the range of intervertebral motion from the end of NZ to the physiological limit of motion. It is characterized by high stiffness secondary to the internal resistance of several soft tissue elements and musculature [9]. A stress-strain curve illustrates the response of the spine to an external stressor. The stress is proportional to the strain at the beginning of the curve, which defines the EZ. The EZ ends at a yield point after which any further strain to the spine results in an irreversible deformation till a breaking point is reached and the spine fails. Posterior elements and ligaments of the spine play a large role in preventing structural failure by supporting tensile loads. The removal of ligamentum flavum and facet joints, however, leads to decrease in tensile stiffness in comparison to intact motion segment outputs [14].

Basic Mechanisms of Load Transfer Mathematical models, based on the concept of mechanical equilibrium and force balance, were utilized to predict the mechanisms of spinal load transfer. As such, Schultz et al. was the first to apply the finite element (FE) method to the spine, which was later on popularized by Shirazi Adl et al. and Goel et al. [15]. A series of sequential decompressive procedures on ten human cadaveric thoracic specimens were performed, which included spinal segment C7-L1, ribs, and sternum with intact articulations [16]. Compared to intact specimens, there were no significant differences in motion between T1–T12 or T7–T11 following sequential decompressive procedures in any of the three planes of motion. This demonstrates that decompression surgeries such as laminectomy, facetectomy, and costotransversecotmy did not have a destabilization effect on the lower thoracic spine. In contrast, a significant decrease in ROM was noticed in all axes following pedicle screw fixation. Such a decrease in motion following instrumentation was more notable in the lower segments of the thoracic spine than in the upper segments at the level of true ribs.

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Influence of Ageing It has been found to influence the load carrying capacity of biological materials. Lately investigators identified the importance of bone mineral density (BMD) on the vertebral body strength. The compressive strength of lumbar vertebral bodies depends on its bone mineral content, which decreases with ageing. Such observation is based on the fact that tensile and compressive properties of adult human IV discs decreases with age when compared to younger populations (20–39 years). In older specimens, mechanical response decreases and the decrease is greater in compressive than distractive properties [14]. It was also observed that compressive and tensile stiffness significantly varied between age groups but were not dependent on gender and segmental level. It has been observed that as age increases, TK increases [5]. This could be secondary to habitual posture, decreased muscle tone, and occupational tolls. However, with the cumulative centred angle measurements, the spine maintained its symmetry with older age.

Influence of Injury or Disease Injuries of the spine, congenital spinal diseases, and degenerative diseases are proven to weaken the spine and its supporting structures increasing the chances of it failing to fulfill its main functions. In 1957, Perey identified the first component of the FSU that fails when axial compression is applied to be the vertebral endplate; this is particularly true in young, non-degenerated specimens secondary to high central loading from the nucleus pulposus [15]. Denis however documented that isolated traumatic or iatrogenic posterior column injuries (during spinal deformity, surgery) did not result in acute instability of the thoracolumbar spine [13]. A retrospective analysis of unstable upper thoracic spinal traumatic fractures to T1–T6 segments treated with hook/rod constructs or pedicle screw fixation suggested 95% fusion with significant reduction in hospital stay [17]. Positive results followed surgical stabilization of the fractures including shorter hospitalization time and faster mobilization (in patients undergoing early surgery).

Influence of Fusion A clear relation exists between biomechanics and fusion, which is observed in the crankshaft phenomenon. This phenomenon, typically, is a consequence of spinal growth biomechanics in both space and time. It is observed when isolated posterior fusion is done on a scoliotic immature spine. In spite of a solid posterior fusion, anterior growth continues at the frontal growth plates resulting in lateral deviation, progressive deformity, and bending of the fusion mass until cessation of growth. When such scenario is anticipated, a preventive anterior epiphysiodesis is required simultaneously with posterior fusion [12].

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Influence of Implants on Thoracic Spine Spinal fixation devices aim at creating a rigid construct with the spine, a construct that maintains position, replaces lost bone, provides stabilization, restores alignment, and prevents motion. Spinal instrumentation is divided, at large, into anterior and posterior instrumentation based on the vertebral body part used to fix the implant to the vertebral column. Anterior instrumentation entails fixing the anterior column, vertebra body proper, while fixing the posterior column, lamina, facets, or pedicles is considered posterior instrumentation. The location of the pathology and the treating surgeon experience are the two most important factors affecting the choice of instrumentation method. Metal has unique properties of mechanical strength, ease of shaping, and for mass production that makes it superior to other materials. Anchoring metal members grip the spinal column at the bony parts and transmit the instrumentation force to the spinal column. As the implant contacts the bone directly, a bone–component interface forms. Anchoring members are divided into two subcategories. Screws and smooth posts belong to subcategory of penetrating anchors with pullout strength, a subcategory of anchors that change shape to offer pullout resistance after bone penetration. Gripping-type anchors, such as wires and hooks, “grip” the vertebra without bone penetration, i.e., lamina, pedicle, spinous process, and the transverse process [18]. Biomechanically, the pullout strength of gripping-type anchors rely on the surface area under the implant and the integrity of the bony structure to which the anchor is attached. The pullout strength decreases markedly even in cases of a minor fracture of the posterior element receiving the anchor. This is turn restricts the utility of such anchors in osteoporotic spine as the cortical bone fails to support the hardware with enough resistance. Gripping-type anchors may intrude the spinal canal increasing the risk of neurologic injury. Thus, gripping anchors are replaced by penetrating anchors. Most hardware will eventually fail from fatigue or non-fusion of bone; thus, and to promote fusion, bone graft material is utilized at the time of implant placement.

Pedicle Instrumentation In 1950, Boucher was the first to describe pedicle screw fixation of the spine; an instrumentation technique that was popularized a decade later by Roy Camille [19]. Even in posterior element defects or severe osteoporosis, such method offers unparalleled rigid fixation. It offers improved segmental control, enhanced deformity correction, and reduction of spinal fractures. Pedicle screws are more resistant to tangential and axial loading than other available implants. Compared to single pedicle screw fixation, triangulation of pedicle screws resulted in higher resistance to pullout and more secure vertebral manipulation [20]. Pedicle screw construct enables concurrent corrective forces in the coronal, sagittal, and rotational translation through providing the vertebral body with three-column fixation.

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In the era of spinal instrumentation, bilateral pedicle screw and rod (PSR) is considered the gold standard technique for spinal stabilization. In a comparative study between PSR and the transvertebral technique, it was found that the former technique (when spanning two levels) has a more stabilizing effect during axial ROM, 66% vs 38% of intact in flexion/extension and 47% vs 27% of intact in axial rotation [21]. However, transvertebral screw and bilateral rods fixation technique across more than one level is equivalent to PSR fixation in the thoracic spine [22].

Sublaminar Wiring Sublaminar wiring (SLW) is a posterior spinal internal fixation technique, requiring the passage of a stainless steel wire beneath a single or a series of contiguous laminae. In upper cervical spine, the wires are wrapped over an onlay bone graft and are placed in a vertical orientation on the posterior aspect of the laminae bilaterally. It is used in thoracolumbar segmental spinal instrumentation in management of scoliosis. In Luque’s technique of management of fracture dislocation, sublaminar wires provide spinal fixation and segmental correction through fixation to the metallic rods at each vertebral segment. Since the advent of pedicle screws, this technique of fixation is used rarely [23]. Biomechanically, SLW construct through contoured dual rods offers only sagittal plane and rotational and/or translational stability. In the absence of anterior column reconstruction, this construct may lead to vertebral collapse being semirigid and poor in axial stability. The surgeons, however, take advantage of this weakness and convert anteroinferior dislodgment forces acting at the site of the fracture into forces for fracture union by controlled collapse [24]. Fibrous tissue forms around the implant isolating metal from dura and acting as a protective shield when removing the wires. This shield protects the meninges against dissemination of infection from bone or soft tissue. During their practice, the authors deny any incidence of stenosis due to this fibrous tissue layers [25]. The wire-related adverse effects are comparable to any other system.

Intervertebral Cages When the vertebral body is compromised by trauma or oncologic vertebral disease, ensuing mechanical instability is regularly corrected with anterior column support to restore spinal integrity (Fig. 1a–d). The other most significant risk factor that predispose patients to interbody subsidence is low BMD. Unfortunately, many of these patients are medically compromised for a corpectomy and anterior column reconstruction. In such cases, to decrease stress on the bony endplates, it is necessary to maximize the end cap size of the implanted interbody cages. This helps sustaining the applied end cap pressure below Young’s modulus of the apposed endplates, thus preventing failure of the endplate and subsidence of the implant [26].

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Fig. 1 (a, b) AP and lateral radiographic view showing tuberculous D8 vertebral collapse in a 60-year-old female with paraplegia; (c, d) One year post-operative AP and lateral radiographic view treated with anterior column reconstruction after corpectomy, PEEK cage, rib graft, and posterior short construct. She had become independent walker after 5 months and bone fusion at 1 year of surgery

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Expandable Corpectomy Cage with a Self-Adjusting, Multiaxial End Cap Adjustable cages prior to compression may help to facilitate the goal of maximization of end cap size. A cadaveric investigation of an expandable corpectomy cage with a self-adjusting, multiaxial end cap showed that such a design significantly increases vertebral end plate contact area and suggests that a cage with such properties may help diminish the risk of subsidence in patients undergoing corpectomy and reconstruction [26]. In fact, wider models were shown to avoid subsidence and better restore segmental lordosis in stand-alone lateral interbody fusion [27]. In order to achieve perfect apposition, cage lordosis must match completely the post-compression segmental curvature at the constructed level. The properties of this corpectomy cage allow it to seal the anterior column defect entirely secondary to being expandable, and to ensure perfect cage-vertebral endplate apposition because of its multiaxial end cap construction. The cage allows this apposition and potentially facilitates bony ingrowth. The long-term fusion rates are as good as conventional, fixed angle cages. Perfect apposition of the cage to vertebral endplates increases baseline stiffness at the interface allowing for the transfer of strain through the interface and promoting local bone growth (Wolff’s law). Both advantages reduce the risk of pseudoarthrosis, a complication that requires revision surgery in more than 2% of the patients. Titanium Mesh Cage The first vertebral replacement cage to be widely used was the titanium mesh cage (TMC), which was introduced in 1986. The TMC fulfills the requirements of reinforcing of the anterior column with regular vertebral body replacement after corpectomy [28]. Extensive laminectomy after decompression, columnotomy, or tumor removal exposes the dura to compression or potential mechanical damage by scar formation and substantially reduces the bony surface thus jeopardizing fusion. Lamina reconstruction protects the dura against mechanical influences. The molded and readily cut TMC can replace the lamina by bridging the dura and is supported by the edges of the laminectomy. The stabilizing implants are kept in place by the elasticity of the titanium. Such reconstruction allows the placement of the bone graft entirely over the laminectomy site enhancing stability by solid continuous bone formation. Titanium Vertebral Body Replacement (VBR) – 3D With the advent of VBR designs, multiple studies have been done to compare different designs for a perfect replacement system. An in vitro study on six human thoracic spine specimens with intact rib cages compared personalized 3D printed titanium VBR to the standard expandable titanium implants. The study found significant, albeit small, changes between both VBR devices. There was increased stability in primary flexion, extension, and axial rotation as well as in lateral bending [29]. Henceforth, 3D printed titanium VBR devices are considered a promising and equivalent alternative to the standard expandable titanium cages.

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Other Implants Rod-Hook Construct Segmental rod-hook constructs share the three-point bending mechanics with the Harrington hook-rod system, which reduces and maintains thoracic kyphosis and prevents sagittal or coronal translation of the disrupted vertebral segments. In contrast to Harrington hooks, proximal and distal hook-pairs (claws) are not dependent on strong distraction forces thus providing a more stable fixation. The segmental systems permit screw or intermediate hooks placement and the rod-lamina contact point provides three-point correcting forces in the sagittal plane. This reduces the likelihood of fixation failure and improves construct stiffness by distributing corrective forces over more laminae. Replacing the hooks by pedicle screws increases fixation strength and maximizes torsional and pullout strength [22].

Long vs Short Fixation Construct Segmental constructs with pedicle fixation improves the strength of fixation and the stiffness of the construct, which in turn promotes a faster recovery with better longterm results for the patients. For thoracolumbar fracture, either a long or a short construct can be used. Long constructs are preferred in thoracic fractures, whereas short constructs work best for lumbar fractures. Extended pedicle screw constructs were introduced in aims to address thoracolumbar fractures [22]. They extend into the lower thoracic region with the least possible alteration of lumbar spinal mechanics and with the adequate corrective forces hence allowing surgeons to re-establish neutral or lordotic alignment and reverse sagittal deformity. The pedicle screw itself is the weak link in the extended construct, which explains the need for a supplemental offset laminar hook, anterior reconstruction, or extra levels of fixation. Otherwise, the pedicle screw bears huge cantilever bending loads that are concentrated between the screw and the lamina distal to the screw hub and distal to the contact point, which increases the risk of segmental collapse. Screws that break after healing are often asymptomatic. If the rod breaks prior to fracture consolidation, progressive material failure is expected, and sagittal collapse may follow even in braced patients. Short-segment pedicle instrumentation (SSPI) is the most widely practiced approach used for treatment of thoracolumbar and lumbar fractures [22]. This approach simultaneously corrects sagittal deformity and translation while immobilizing the shortest possible lumbar spinal section. The most effective method in treating thoracolumbar spine burst fractures is hyperlordotic reduction and SSPI along with an intermediate screw, because regardless of the fracture load-sharing classification score, the failure rate is very minimal [30]. Typically, SSPI constructs cannot provide three-point bending forces; instead, it depends on cantilever bending moments to withstand axial and rotational forces. SSPI, however, can hardly resist axial instability to maintain sagittal correction. In cases where anterior and middle

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spinal columns are unable to share substantial axial loads, the pedicle screw bears the load in a cantilever bending mode. Once the construct starts to fail, surgeons expect future collapse along with further increased incidence of loss of lordosis, pain, and deformity. It was discovered that pedicle screw failure is eliminated by manually elevating the fractured endplate and re-establishing vertebral height through performing transpedicular bone grafting [31]. As such, patients having intact or reconstructed anterior column tend not to experience screw failure. Regardless of surgical approach or length of instrumentation, thoracic spinal stability is maintained after VBR [32]. Long instrumentation may be recommended after VBR of the thoracic spine to avoid failure of the implant, loosening of the pedicle screw, or contiguous segmental disease. Short instrumentation, however, is an appropriate alternative in individuals who are medically compromised as it provides adequate primary stability.

Implant Failures Spinal fixation has undergone significant changes since the development of biocompatible materials in the 1940s. Such materials can be kept in position for life and can endure repeated stressors experienced during weight bearing or directional movements until fusion occurs. Spinal hardware may fail when incorrectly selected or placed. Late complications include migration, dislodgment (Fig. 2a–c), and implant failure. The hardware may fail at the fixation site such a loose screw, dislodged hook, broken wire, or a break at the junction of hardware components, for example, a rod might fracture at the middle portion or slide off the pedicle screw. Failure may as well follow bone fracture or infection resulting in fusion failure along with development of pseudarthrosis.

Fig. 2 (a) Lateral radiographic view showing severe thoracolumbar kyphosis; (b) 3 month postoperative lateral radiographs showing posterior fixation to L2 (near the apex of the curve); (c) One year postoperative lateral radiographs showing dislodgment of the distal screws required revision surgical fixation distally

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Hardware fracture occurs most commonly due to metal fatigue from the repeated stress of spinal movement. Other complications associated with the spinal hardware fixation include device malposition, lateral dislodgment or fracture, soft tissue injuries, or postoperative infection. Such complications contribute to further instability, pain, failure of fusion, and possible neurovascular damage [33]. However, an implant that can support different anatomical variations and still overcome all complications and unexpected difficulties remains unsound and impossible to design.

Pedicle Screws The pedicle screw construct was found to have the highest failure load than the other traditional constructs available suspected to be secondary to a difference in the device–bone interface [20]. To share the bending moment applied to pedicle screws, supplemental offset laminar hooks have been used. However, if the hook is used at the same level, there is no additional improvement in the failure load of the pedicle screws [20]. In cases of inadequate fixation conditions, such as osteoporosis, failure and loosening of the screws have been reported. Low BMD in osteoporosis also influences the pedicle screws to pull out of bone resulting in non-union of the construct, sagittal collapse or, painful kyphosis. As such, bone resorption follows especially around the screws and under the implant, which is in immediate contact with the bone. This results in instability and movement of the hardware thus leading to failure of fixation and fracture of the weak osteoporotic bone [20]. Henceforth, in elderly or osteoporotic patients, the use of pedicle screws is unfavourable and hook fixation is preferred [34]. Ninety-one patients with spinal problems who had 648 consecutively inserted pedicle screws were reviewed for complications [35]. Neurological injury was the most frequent complication. Blumenthal and Gill reported a 6% rate of complications vs 1.09% neurological complications rate although significant nerve injury rate by a screw was 0.15% [35].

Rods Rod fracture (RF) is a common complication after spinal fusion surgery (Fig. 3a–c). It was observed that 6.8% of adult spinal deformity cases and 15.8% of pedicle subtraction osteotomy (PSO) cases had a symptomatic RF [36]. This might be secondary to stress at the PSO site as it was noticed that early failure was most common after PSO. Nonideal choice of angle during placement, inadequate bone graft, postoperative sagittal malalignment, and poor fusion may play an important role in rod breakage and contribute to implant failure. One of the most important factors contributing to RF is insufficient correction [37]. In addition, sagittal imbalance progression can lead to hardware mobilization and breakage [38].

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Fig. 3 (a) AP radiographic view showing inappropriate fixation in a 16-year-old with thoracic scoliosis (One long and one short rod); (b) Postoperative AP radiographic view after 5 months showing stress riser in the thoracolumbar area due to shorter rod causing the long rod to fracture with loss of scoliosis correction

Sublaminar Wire The SLW construct distributes stress over a small area of the bone when compared to other constructs, thereby increasing the risk of failure at the bone–device interface and providing less predictable fixation in osteoporotic bone. There exists a direct correlation between number of consecutive laminae the wire passes beneath, the degree of anterior bowing, and the complication rate. The complications involve wire breakage, slipping off the bony attachment site, or cutting through the bone [20].

Summary The thoracic spine is the middle segment of the spinal complex. Being a muscle controlled section, it ensures and promotes high stability, sagittal balance, optimum transitory force from the cervical to the lumbar spine, in addition to supporting the adequate flexibility required to perform three-dimensional movements. The spine is

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a three-column system with the rib cage considered as a fourth column in the thoracic section. Spinal instrumentation has revolutionized the treatment of spinal fractures, deformities, or tumors. Unstable thoracic fractures or diseased vertebrae can be stabilized with transpedicular screws, sublaminar wiring, or intervertebral cages. Scoliosis, osteoporosis, or small pedicles are risk factors for pedicle screw failure. The length, diameter, and design of the screws can affect the biomechanical strength of screw fixation. Anterior load bearing structural grafts and interbody devices, e.g., titanium mesh cages, expandable cages, or VBRs increase construct stiffness, decreases posterior implant failure, and enhances the rate of successful spinal fusion. Symptomatic implant failure may require revision surgery.

References 1. Watkins R 4th, Watkins R 3rd, Williams L, et al. Stability provided by the sternum and rib cage in the thoracic spine. Spine (Phila Pa 1976). 2005;30(11):1283–6. https://doi.org/10.1097/01. brs.0000164257.69354.bb. 2. Brasiliense LB, Lazaro BC, Reyes PM, Dogan S, Theodore N, Crawford NR. Biomechanical contribution of the rib cage to thoracic stability. Spine (Phila Pa 1976). 2011;36(26):E1686–93. https://doi.org/10.1097/BRS.0b013e318219ce84. 3. Liebsch C, Graf N, Wilke HJ. In vitro analysis of kinematics and elastostatics of the human rib cage during thoracic spinal movement for the validation of numerical models. J Biomech. 2019;94:147–57. https://doi.org/10.1016/j.jbiomech.2019.07.041. 4. O’Brien MF, Kuklo TR, Blanke KM, Lenke LG. Spinal Deformity Study Group radiographic measurement manual. Medtronic Sofamor Danek 2008;6(1):1–10. 5. Lafage R, Steinberger J, Pesenti S, et al. Understanding thoracic spine morphology, shape, and proportionality. Spine (Phila Pa 1976). 2020;45(3):149–57. https://doi.org/10.1097/BRS. 0000000000003227. 6. Lee DG. Biomechanics of the thorax – research evidence and clinical expertise. J Man Manip Ther. 2015;25(3):128–38. 7. McCarthy C. Combined movement theory: rational mobilization and manipulation of the vertebral column. Elsevier. 2010;13(10):165–78. 8. Aeby CT. Die Altersverschiedenheiten Der Menschlichen Wirbelsäule. Arch Anat Physiol. 1879;10:77. 9. Shillingford JN, Lin JD, Lehman Jr. RA. Biomechanics of the thoracic spinal column. eBook Collection (EBSCOhost) 2020;2:E10–E14. 10. Panjabi MM, White AA 3rd. Basic biomechanics of the spine. Neurosurgery. 1980;7(1):76–93. https://doi.org/10.1227/00006123-198007000-00014. 11. Wilke HJ, Grundler S, Ottardi C, Mathew CE, Schlager B, Liebsch C. In vitro analysis of thoracic spinal motion segment flexibility during stepwise reduction of all functional structures. Eur Spine J. 2020;29(1):179–85. https://doi.org/10.1007/s00586-019-06196-7. 12. Dubousset J. Biomechanics of the spine during growth. Biomech Biomater Orthop. 2004;22: 255–81. https://doi.org/10.1007/978-1-4471-3774-0_27. 13. Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976). 1983;8(8):817–31. https://doi.org/10.1097/00007632198311000-00003. 14. Stemper BD, Board D, Yoganandan N, Wolfla CE. Biomechanical properties of human thoracic spine disc segments. J Craniovertebr Junction Spine. 2010;1(1):18–22. https://doi.org/10.4103/ 0974-8237.65477.

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15. Oxland TR. A history of spine biomechanics. Focus on 20th century progress. Unfallchirurg. 2015;118(Suppl 1):80–92. https://doi.org/10.1007/s00113-015-0087-7. 16. Lubelski D, Healy AT, Mageswaran P, Benzel EC, Mroz TE. Biomechanics of the lower thoracic spine after decompression and fusion: a cadaveric analysis. Spine J. 2014;14(9): 2216–23. https://doi.org/10.1016/j.spinee.2014.03.026. 17. Gattozzi DA, Friis LA, Arnold PM. Surgery for traumatic fractures of the upper thoracic spine (T1-T6). Surg Neurol Int. 2018;9:231. https://doi.org/10.4103/sni.sni_273_18. Published 2018 Nov 19 18. Suk SI, Kim WJ. Biomechanics of posterior instrumentation for spinal arthrodesis. Biomech Biomater Orthop. 2016;35:437–67. https://doi.org/10.1007/978-1-84882-664-9_35. 19. Suk SI, Kim WJ. Pedicle screw fixation in thoracic or thoracolumbar burst fractures. Biomech Biomater Orthop. 2016;33:405–27. https://doi.org/10.1007/978-1-84882-664-9_33. 20. Hongo M, Ilharreborde B, Gay RE, et al. Biomechanical evaluation of a new fixation device for the thoracic spine. Eur Spine J. 2009;18(8):1213–9. https://doi.org/10.1007/s00586-0090999-4. 21. Rodriguez-Martinez NG, Savardekar A, Nottmeier EW, et al. Biomechanics of transvertebral screw fixation in the thoracic spine: an in vitro study. J Neurosurg Spine. 2016;25(2):187–92. https://doi.org/10.3171/2015.11.SPINE15562. 22. McLain RF. The biomechanics of long versus short fixation for thoracolumbar spine fractures. Spine (Phila Pa 1976). 2006;31(11 Suppl):S70–S104. https://doi.org/10.1097/01.brs. 0000218221.47230.dd. 23. Geremia GK, Kim KS, Cerullo L, Calenoff L. Complications of sublaminar wiring. Surg Neurol. 1985;23(6):629–35. https://doi.org/10.1016/0090-3019(85)90017-5. 24. Patil SS, Bhojaraj SY, Nene AM. Safety and efficacy of spinal loop rectangle and sublaminar wires for osteoporotic vertebral compression fracture fixation. Asian J Neurosurg. 2017;12(3): 436–40. https://doi.org/10.4103/1793-5482.175648. 25. Lea-Plaza C, Vin Vivo E, Silveri A, Bermudez W, Santo J, Carreras O. Surgical correction of scoliosis with a new three- dimensional device, the Lea-Plaza frame: a preliminary report. Spine (Phila Pa 1976). 1992;17(3):365–72. 26. Stinchfield T, Vadapalli S, Pennington Z, et al. Improvement in vertebral endplate engagement following anterior column reconstruction using a novel expandable cage with self-adjusting, multiaxial end cap. J Clin Neurosci. 2019;67:249–54. https://doi.org/10.1016/j.jocn.2019. 06.017. 27. Marchi L, Abdala N, Oliviera L, et al. Radiographic and clinical evaluation of cage subsidence after stand-alone lateral interbody fusion clinical article. J Neurosurg Spine. 2013;19(1):110–8. 28. Grob D, Daehn S, Mannion AF. Titanium mesh cages (TMC) in spine surgery. Eur Spine J. 2005;14(3):211–21. https://doi.org/10.1007/s00586-004-0748-7. 29. Liebsch C, Vogt M, Jansen JU, Wilke HJ. In vitro comparison of personalized 3D printed versus standard expandable titanium vertebral body replacement implants in the mid-thoracic spine using entire rib cage specimens. Clin Biomech. 2020;78:105070. https://doi.org/10.1016/j. clinbiomech.2020.105070. 30. Kose K, Inanmaz M, Isik C, et al. Short segment pedicle screw instrumentation with an index level screw and cantilevered hyperlordotic reduction in the treatment of type-A fractures of the thoracolumbar spine. Bone Joint J. 2014;96-B(4):541–7. 31. Ebelke DK, Asher MA, Neff JR, Krake DP. Survivorship analysis of VSP instrumentation in the treatment of thoracolumbar and lumbar burst fractures. Spine. 1991;16:428–92. 32. Liebsch C, Kocak T, Aleinikov V, Kerimbayev T, et al. Thoracic spinal stability and motion behavior are affected by the length of posterior instrumentation after vertebral body replacement, but not by the surgical approach type: an in vitro study with entire rib cage specimens. Front Bioeng Biotechnol. 2020;8:572. https://doi.org/10.3389/fbioe.2020.00572.

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33. Slone RM, MacMillan M, Montgomery WJ. Spinal fixation: complications of spinal instrumentation. Radiographics. 1993;3:797–816. 34. Gayet LE, Pries P, Hamcha H, Clarac JP, Texereau J. Biomechanical study and digital modeling of traction resistance in posterior thoracic implants. Spine. 2002;27:707–14. https://doi.org/10. 1097/00007632-200204010-00007. 35. Faraj AA, Webb JK. Early complications of spinal pedicle screw. Eur Spine J. 1997;6(5):324–6. https://doi.org/10.1007/BF01142678. 36. Smith JS, Shaffrey CI, Ames CP, et al. Assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity. Neurosurgery. 2012;71(4):862–7. https://doi. org/10.1227/NEU.0b013e3182672aab. 37. Tang C, Li GZ, Kang M, Liao YH, Tang Q, Zhong J. Revision surgery after rod breakage in a patient with occipitocervical fusion: a case report. Medicine (Baltimore). 2018;97(15):e0441. https://doi.org/10.1097/MD.0000000000010441. 38. Berjano P, Bassani R, Casero G, Sinigaglia A, Cecchinato R, Lamartina C. Failures and revisions in surgery for sagittal imbalance: analysis of factors influencing failure. Eur Spine J. 2013;22(Suppl 6):S853–8. https://doi.org/10.1007/s00586-013-3024-x.

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sagittal Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mechanical Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anatomical Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Vertebral Body and Facets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intervertebral Disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ligaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Muscles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Physiology of Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Failure Modes of Motion Segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fracture Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Disc Degeneration and Altered Biomechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Segmental Instability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Back Pain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The Effect of Fusion on Kinematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Implants in Lumbar Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Posterior Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anterior Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Knowledge of lumbar spine morphology and functional anatomy is essential in understanding the relationship between the structures and spinal activity. The shape of the normal spinal curvature in the sagittal plane is essential for maintaining an erect, vertical, and bipedal position. The lumbar spine plays a key role in supporting A. Ghoshal (*) · M. J. H. McCarthy University Hospital of Wales, Cardiff, UK e-mail: [email protected]; [email protected]; [email protected] © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_115

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the upper spine and allowing range of motions. Its main functions include maintaining the equilibrium of the upper spine, providing trunk stability, neural protection, biodynamics, and haematopoiesis. The pelvis also shares an intrinsic anatomic relationship with the lumbar spine and is equally important in maintaining an upright posture. As the centre of gravity changes with body position, the pelvis tilts by rotating around the femoral heads, thus compensating for the imbalance by maintaining the gravity line between the two feet. Problems such as pain or instability may arise in the lumbar spine during performance of activities of daily living, through either improper posture or injury. Fusion is the current gold standard treatment for many such conditions, however, it alters the normal biomechanics of the spine. Various makes and types of implants are used in the lumbar spine. A sound knowledge of the biomechanics is therefore necessary to enable a better understanding of the implants used in the lumbar spine to rectify the clinical problems we face. This chapter discusses the rationale behind the implants for usage in the lumbar spine. Keywords

Lumbar spine · Sagittal alignment · Biomechanics · Implants · Fusion

Introduction To appreciate the biomechanics of the lumbar spine, knowledge of the morphology and functional anatomy is essential in understanding the relationship between the structures and spinal activity. The main functions of the lumbar spine are maintaining the equilibrium of the upper spine, providing stability to the trunk, neural protection, and biodynamics [1]. The spine also contributes to hematological cell formation through its large content of bone marrow.

Sagittal Alignment The shape of the normal spinal curvature in the sagittal plane is essential for maintaining an erect, vertical, and bipedal position. Humans are the only vertebrates to have a lordotic lumbar spinal curvature which allows them to stand and walk. Spinal sagittal curves appear progressively with growth and are well established by the time a child begins to stand and walk. The pelvis shares an intrinsic anatomic relationship with the lumbar spine and is equally important in maintaining an upright posture. The shape of the pelvis and its relationship to the sacral slope dramatically influences the type of lumbar lordosis in an individual. Roussouly originally described four main types of lumbar lordosis based on the relationship of the lumbar lordosis and sacral slope; this was recently modified to include five types [2]. Type 1 curves have a long thoracolumbar kyphosis and short lumbar hyperlordosis; type 2 curves have a flat lordosis; type 3 curves have a regular lordosis; and type 4 curves are hyperlordotic. The recent modification identifies a

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Fig. 1 Revised Roussouly classification of spine types integrating the anteverted pelvis shape (Ref. [2]) (PI – Pelvic Incidence)

novel type 3 “anteverted pelvis” sagittal shape with a low pelvic incidence, low or negative pelvic tilt, and lumbar hyperlordosis (Fig. 1). Pelvic incidence is specific to an individual and is the main axis of the sagittal balance of the spine. As the centre of gravity changes with body position, the pelvis tilts by rotating around the femoral heads, thus compensating for the imbalance by maintaining the gravity line between the two feet [3]. This compensatory mechanism continues until compensation is no longer possible and the individual can no longer maintain an upright posture.

Mechanical Stability The functional spinal unit (FSU), initially described by Junghanns [4], represents the smallest mechanical unit of the spine consisting of two adjacent vertebrae and all intervening structures, including the ligaments, apophyseal joints, and intervertebral disc. These structures are divided into anterior and posterior groups based on their anatomical location in relation to the posterior longitudinal ligament (PLL).

Anatomical Differences Vertebral Body and Facets The cancellous bone within the vertebra behaves in an elastic manner, absorbing forces under normal physiological loading. As the vertebrae are loaded in series from cranial to caudal, the lumbar vertebrae support a greater share of the body weight, thus accounting for their increasing size.

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The facet joints from L3 to the sacrum gradually assume a more coronal orientation from proximal to distal, which allows for a greater range of flexion motion in the sagittal plane, whilst resisting gross rotatory instability [5]. The superior articular processes of the inferior vertebrae face dorsomedially and the inferior articular processes of the superior vertebrae face ventrolaterally, effectively locking together during axial rotation of the lumbar spine [6]. This mechanism is also thought to protect the intervertebral disc from excessive sheer and torsional forces [7]. In addition to the sagittal facet joint alignment, the facet capsule helps limit excessive joint motion by controlling axial rotation and posterior sliding during extension [8].

Intervertebral Disc The annulus is a strong radial tire-like structure containing type 1 collagen fibers which are organized into concentric lamellae and orientated at different angles. Proteoglycans within the nucleus pulposus attract and retain water, leading to natural swelling of the disc, which provides resistance to compressive forces. With normal physiological loading, the outer fibers of the annulus provide the first restriction to abnormal micromotion in the intact lumbar FSU. The force is then evenly distributed to the end plates by the healthy disc. This architecture provides the disc with both the tension-resisting properties of a ligament and the compression-resisting properties of articular cartilage [9].

Ligaments Spinal ligaments transmit tensile loads only and specifically limit excessive motion. Generally, in the lumbar spine, the load to failure values are highest for the ligaments furthest away from the axis of rotation, as they must withstand functionally more force and deformation [10, 11]. The ALL is the strongest with an approximate failure load of 450 N. The PLL is narrower, thinner, and weaker than the ALL with an approximate failure load of 325 N [1, 12].

Muscles Muscle forces stabilize the FSU by stiffening the motion segments, particularly during flexion and extension. In this role, the multifidus has the strongest influence, being responsible for greater than two-thirds of the stiffness increase [13]. Concurrent antagonistic coactivation of the abdominal muscles also occurs during range of movement, which further helps stabilize the lumbar spine [14]. Hence, the importance of improving the so-called “core muscle stability” in the management of spinal disorders.

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Physiology of Loading The human upright stance puts great stress on the lower spinal segments. Moreover, the mechanical stress significantly increases with the upper body deviation from the mid-line or whilst carrying a load. In an upright standing posture, the cancellous vertebral body carries 70–90% of the axial body load. The cancellous bone can withstand up to 9.5% of deformation before failure, whereas the cortical bone can only withstand up to 2%. The facet joints carry between 10–20% of the axial body load, increasing to 30% in hyperextension. Axial rotation results in a larger force in the contralateral facet joint [15]. The facet joints also carry up to 50% of anterior shear load in a flexed posture, transmitting compressive loads by surface contact and resisting tensile loads through the joint capsule. The annulus fibrosus resists tensile, compressive, and hoop stresses through the circumferential orientation of its fibers. Discontinuous fiber layers predispose the annulus to fail through separation of the lamellar layers and formation of circumferential or radial tears. The amount of water imbibed by the nucleus pulposus varies throughout the day and changes with activity [16]. As the nucleus swells, it develops a base internal pressure. When the disc is loaded, pressure is exerted in all directions, which also increases the stiffness of the annulus and end plates. The nucleus pressure is greatly influenced by the trunk position, external loads, and paraspinal muscle tension balancing those external loads. Takahashi reported a proportional increase in the mechanical load on the lumbar disc with progressive tilting angle of the trunk, from upright to 30 of flexion [17]. The largest pressure increases occurred in the posterolateral annular region during axial compression in combination with lumbar flexion and axial rotation [18–20].

Kinematics In the lumbar spine, motion is relatively unconstrained and complex, displaying six degrees of freedom (flexion/extension, lateral bending, and axial rotation). Coupled rotational movements are also seen during range of motion secondary to the orientation of the facet articulations and the lumbar lordosis [21]. In the normal lumbar spine, the primary range of flexion-extension increases caudally from L1 to S1, whereas the axial rotation and lateral bending remain relatively constant [22]. The left lateral bending causes a right axial rotation in the upper segments but causes the left axial rotation in the lumbosacral joint; the opposite occurs during a right lateral bending [23]. The L4/5 segment constitutes a transitional level and demonstrates variability in the direction of the coupled motion amongst individuals [24]. Structural changes that affect the stability or flexibility of the motion segment can significantly alter the coupled motion.

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Failure Modes of Motion Segment The distribution and magnitude of loads on the lumbar spine vary considerably and influence the patterns of failure observed. The vertebral endplate experiences initial failure in both ultimate compressive strength and fatigue failure. Vertebral body fractures and facet joint failure are also seen in compressive loading tests. Discs may fail when compressed in flexion, combined with the axial rotation, or from a cascade initiated by the endplate failure [25].

Fracture Patterns Thirty-six human cadaver lumbar motion segments were fatigue tested, and it was observed that stellate endplate fractures were associated with increased posterior shear forces and less degenerated discs. Fractures running laterally across the endplate were associated with motion segments having larger volumes, whereas endplate depression was more common in smaller specimens, as well as those experiencing increased posterior shear forces. Facet joint damage was significantly associated with the degree of lumbar flexion, with damage being greatest in the neutral posture [25].

Disc Degeneration and Altered Biomechanics The intervertebral disc and facet joints function as a “three-joint complex” whereby changes in one joint affect the biomechanics of the whole complex. As degeneration progresses through normal aging and repetitive micro-injury, the complex initially demonstrates dysfunction, followed by micro and macro-instability, and finally stabilization (the Kirkaldy- Willis degenerative cascade). The shape of the spine is one of the main factors implicated in degenerative evolution. In type 1 spines, there is an increased risk of disc degeneration and retrolisthesis in the thoracolumbar region due to the excessively tilted angle of the discs. In younger patients, L4-S1 hyperextension leads to the spinous process “kissing” with increased facet pressure and risk of developing an L5 spondylolysis. Type 2 spines are at higher risk of developing early disc degeneration with central disc herniation secondary to a flat lordosis imparting maximum pressure to the horizontally orientated discs. Type 3 spines are relatively well-balanced with no characteristics for a specific degenerative process. Type 4 hyperlordotic spines are at increased risk of developing L5 isthmic lysis through shear forces. Older patients are also at higher risk of developing facet arthritis and degenerative L4/5 spondylolisthesis [3].

Segmental Instability Segmental instability occurs when an applied force produces displacement of part of a motion segment exceeding that found in a normal spine [26]. It results from the

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disruption of passive structures (disc, ligaments, and joint capsule) through either congenital anomalies, such as spondylolysis, or acquired disease processes such as degeneration, infection, neoplasm, trauma, or surgery. Instability can lead to changes in spinal alignment and range of motion through alterations in segmental stiffness and coupled motion. Increased loading of the lumbar spine may thus provoke abnormal segmental motion and deformity, which may be visualized on radiographic images [27]. Long-standing instability can lead to pathological deformity such as degenerative spondylolisthesis. The incidence of facet joint tropism is also higher in patients with degenerative disc disease, which can place additional torsional stresses on the annulus fibrosus and lead to an increased risk of disc herniation [28].

Back Pain Pain is a protective mechanism in the human body. The onset of back pain elicits a physiological reflex response, which causes muscle spasm and acts to immobilize the affected area to prevent further injury. Intervertebral discs are a common source of chronic low back pain, with pain arising from the combined effects of mechanical damage and a biological response to that damage (the outer annulus fibrosus has a nerve supply). Annular fissures provide a pathway for nuclear material to herniate out onto the perineural tissue, causing mechanical compression and eliciting a painful inflammatory response. Facet joints are also highly innervated and have been implicated in chronic back pain [29].

The Effect of Fusion on Kinematics Although fusion is the current gold standard treatment for a variety of spinal conditions, it alters the normal biomechanics of the spine. The loss of motion at the fused levels is compensated by an increased motion at adjacent unfused segments. This excessive motion can lead to premature degeneration of the adjacent facet joints, with translation of the adjacent segment producing a listhesis and canal stenosis. Facet hypertrophy, thickening of the ligamentum flavum and degenerative disc prolapse may further contribute to the stenosis and result in neural compression with an onset of radicular symptoms (adjacent segment disease – ASD). Modern fusion techniques focus on restoring the spinal alignment according to an individual’s shape of spine to ensure optimal biomechanical alignment for that individual and prevent ASD. Dynamic stabilization methods have also been proposed with the hope that it can prevent degeneration of adjacent segments (Fig. 2). St-Pierre et al. utilized a dynamic stabilization system without fusion to treat patients with spinal stenosis and neurological symptoms [30]. They reported that non-fusion was not protective against developing symptomatic ASD, with a rate of 29% seen at long-term follow up. They also found that pre- existing ASD was the strongest predictor for developing post-operative ASD.

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Fig. 2 (a and b) AP & Lateral X-rays of a 52-year-old man with pedicle screws and rods at L5/S1 and dynamic stabilization at L4/5 with a flexible cord spacer; (c) Schematic representation of the hybrid fixation. (Illustration image courtesy of Globus Medical Inc.)

Implants in Lumbar Spine Apart from dynamic stabilization techniques and arthroplasty, the end goal of spinal stabilization is to achieve a solid bony fusion. Many devices and techniques are available to facilitate this goal, each with its own unique structural and biomechanical characteristics. Therefore, the surgeon must choose the appropriate implant and technique based on a thorough understanding of these characteristics and the specific nature of each case to achieve a successful outcome.

Posterior Instrumentation The majority of posterior systems derive their stability from a solid anchorage in the pedicle and the inherent rigidity of the connecting instrumentation. Pedicle screw and rod constructs are the current gold standard for instrumented lumbar fusions. Fixation through the pedicle is safe and effective, and allows significant control of the entire vertebral body.

Pedicle Screws The pedicle screws consist of a head, neck, and body. The body may be conical or cylindrical. They have a major outer and minor inner diameter; the difference between the two is the thread depth. The pitch of the thread is the distance between the crests of two adjacent threads. The head of the screw can be either monoaxial or polyaxial (Fig. 3). Monoaxial screws are weakest at the neck whilst polyaxial screws are weakest at the point of head- screw coupling.

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Fig. 3 (a–h) Examples of the different types of pedicle screws available: (a) monoaxial screw with quarter turn cap; (b) polyaxial modular screw with quarter turn cap; (c) polyaxial modular screw with dual tulip and threaded cap; (d) percutaneous polyaxial cannulated screw with long tabs to protect soft tissues; (e) hydroxyapatite-coated polyaxial dual outer diameter screw; (f) fenestrated screw to allow cement augmentation (injected down the centre of the screw); (g) polyaxial and monoaxial crosslink; (h) posterior view of lumbar construct with pedicle screws, rods, and crosslink. (Images courtesy of Globus Medical Inc.)

Pullout strength of the screw is determined by its outer diameter, the quality of bone between the threads, and pedicle morphology, whereas fatigue strength is related to the inner diameter of the screw. Screw purchase in the pedicle is more important in resisting pullout than the vertebral body. Convergence of screws by 30 in the coronal plane can also increase the pullout strength by approximately 30%. Decreased bone mineral density and tapping prior to screw insertion reduces pullout strength, although under tapping by 1 mm conserves the same pullout strength as an untapped screw [31]. A cephalad screw trajectory in the sagittal plane must also be avoided to reduce the risk of early fatigue and failure [32]. In severely osteoporotic bone or during revision surgery, pullout strength can be improved through various augmentation techniques. Bone cement may be injected

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Fig. 4 L1 burst fracture with kyphosis and ankylosed lever arm above. The patient had instability pain and osteoporosis. Posterior instrumentation with fenestrated pedicle screws and cement augmentation was performed. (Image courtesy of Globus Medical Inc.)

into the screw hole prior to screw insertion or through fenestrated pedicle screws (Fig. 4); alternatively, larger diameter, dual-thread [33], or hydroxyapatite-coated screws may be considered, along with the addition of supplemental hooks and sublaminar bands/wires. In recent times a cortical bone trajectory, using a cortically threaded screw, has been advocated to increase pullout strength by allowing an increased cortical bone purchase in the lamina and pedicle. This is especially effective in poorly trabeculated osteoporotic bone [32, 34]. The use of two transverse connectors improves the axial rotational stability in cases with anterior column instability or when correcting rotational deformity [32] (Fig. 3). An increase in rod diameter and/or the number of rods used (e.g., quad-rod constructs) also increases the construct stiffness, but can cause higher rates of screw breakage through the transmission of higher internal loads within the screws. Therefore, a balance between an absolutely rigid fixation and minimal risk of implant failure must be achieved [35] (Figs. 5, 6, and 7).

Other Screw Types Transfacet screw fixation was first described by Toumey and King in the 1940s and may be used to supplement the lumbar interbody fusion. Transfacet screws can be percutaneously implanted, which potentially minimizes morbidity, and may

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Fig. 5 (a & b) 9 month post-operative AP and Lateral views of lumbosacral spine showing failure of instrumentation, proximal kyphosis and loss of sagittal balance in a 68 year-old-male following a fall. (c & d) revision surgery showing salvage of failed lumbar spine fixation treated with L4 pedicle subtraction osteotomy to realign the spine, quad rod construct, and interbody cages at L2/3 and L3/4

represent an alternative to pedicle screws for select cases. However, the effective length of the screw that can resist a flexion moment is relatively short, therefore these screws should be used when the anterior column is intact [36].

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Fig. 6 Top row – example of an L1 incomplete burst fracture with flexion distraction and posterior column bony ligamentous injury. This was reduced and internally fixed (note the divergent screw direction on the lateral image to increase fixation stability). Bottom row – on the left is an example of an acute L5 pars fracture repair with cannulated partially threaded screws through the pars interarticularis. The images in the centre and right show failure of single level above single level below polyaxial screw fixation of an L3 split burst fracture. The fixation has failed at the screw crown interface due to the lack of anterior column support (note the change in screw crown angulation of the top screws)

Pars screws with bone grafting may be considered for the treatment of symptomatic spondylolysis in younger patients. The technique focuses on direct repair of the pars defect, which preserves segmental motion and decreases risk of subsequent spondylolisthesis. Studies have reported high fusion and low complication rates [37] (Fig. 6).

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Fig. 7 Example of a T12 bony Chance fracture treated with monoaxial percutaneous pedicle screw fixation. Note that the screws are cannulated

Hollow modular anchorage (HMA) screws are useful in promoting interbody fusion, as the hollowness can be filled with cancellous bone graft. However, supplementary pedicle screw fixation is necessary to protect the HMA screws, and together they provide a stable construct that can achieve a circumferential fusion in high-grade spondylolisthesis [38] (Fig. 8).

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Fig. 8 (a) Lateral views of Lumbosacral spine X-ray showing high-grade developmental L5/S1 spondylolisthesis in a 26-yearold male. (b) One-year postoperative lateral views of lumbosacral spine X-ray showing posterior pedicle screw fixation and a trans L5/S1 HMA screw used to achieve fusion across the slip

Transdiscal screws are also commonly used to treat high-grade spondylolisthesis. Although technically more challenging to insert, there is a reported lower incidence of neurological injury, with better radiological and functional outcomes in the medium term than conventional pedicle screw fixation [39]. Sacro-pelvic fixation with iliac screws has become a well-established technique to protect the sacral instrumentation in long constructs involving the sacrum. Such constructs place significant biomechanical stress on the S1 pedicle screws, especially during flexion. Complications including screw loosening, pullout, and pseudarthrosis at the lumbosacral junction can occur, as the S1 pedicle is larger and more cancellous than its lumbar counterparts. Utilizing dual-iliac screws reduces complication rates through increasing construct stiffness in compression and torsion [40]. Iliac screws are positioned laterally in relation to the S1 pedicle screw and require an offset connector to connect the iliac screws to the rod. Recently developed S2-alar-iliac (S2AI) screws allow increased pelvic fixation with a lower-profile screw and rod construct. These screws can be inserted percutaneously or free-hand and require less soft tissue dissection, as the entry point is medial to the traditional iliac screw. This avoids the complications of prominent instrumentation. Biomechanical studies have shown no significant differences between iliac and S2AI screws in terms of construct stiffness and failure [41] (Figs. 9 and 10).

Spinous Process Fixation Wires or sutures around the spinous processes were the earliest spinal implant, first described by Hadra in 1891. However, this construct can only resist tensile loads.

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Fig. 9 Example of a pathological L5 fracture with compression of the cauda equina. This has been treated with polyaxial screw fixation two levels above and two levels below using S2 alar iliac screws. There has also been a posterior decompression. Using polyaxial screws in long constructs does not tend to result in screw failure as demonstrated in Fig. 6 (if there was a significant lack of anterior support, it is more likely that the rods would break in such cases)

Anterior shear forces rely on the presence of intact facet joint articulations and high failure rates are observed when significant comminution is present in the posterior vertebral body.

Lamina Hooks and Wires The development of a hook and rod system in the 1960s was a milestone in thoracic spine and scoliosis surgery. The two main types of hooks in use are pedicle and laminar. Lamina hooks provide cranial and caudal support in the thoracic and lumbar spine but must enter the neural canal to anchor to the lamina. Pedicle hooks do not enter the neural foramen and provide stronger anchoring power, although they can only translate the correction force cranially in the thoracic spine.

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Fig. 10 Example of a lumbosacral fracture dislocation treated with L4 to S2 posterior fixation with S2AI screws (In this case the screw heads did not line up so a rod-to-rod connector was required on the left between the S1 and S2AI screws). Note the importance of getting a true lateral of the sciatic notches to ensure appropriate S2AI screw position (inlet and outlet pelvis views intraoperatively are also useful)

Historically, Luque’s sublaminar wire was the first attempt to provide segmental fixation. Sublaminar wires provide stable fixation for each vertebral segment but do not reduce coronal and rotational deformities as well as pedicle screw constructs. Both hooks and wires have poor ability to control rotation and lateral bending moments. They are mainly used to supplement the standard pedicle screw and rod-based constructs [42].

Interspinous Posterior Device Interspinous posterior devices (IPD) are a group of implants used to treat degenerative lumbar stenosis and neurogenic claudication. They primarily aim to dynamically neutralize the segmental hypermobility underlying the onset of the pathological condition, rather than preserve movement. A further evolution has led to the development of interspinous fusion devices whose aim is interspinous bone fusion and obliteration of segmental motion. Distraction of the spinous processes occurs following implantation of the IPD. The ligamentum flavum is stretched and stenotic narrowing is reduced. Axial load is

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transferred into the anterior compartment, causing alteration in the spinal biomechanics and resulting in a negative sagittal balance. The overload applied to the spinous processes can lead to fracture or lacerate the posterior longitudinal ligament, causing loosening and displacement of the device. Due to high reoperation rates and progression of degenerative changes their use has diminished significantly over the last decade [43].

Facet Arthroplasty Total facet arthroplasty devices are modular, implantable, semiconstrained devices designed to replace the facet joints and posterior elements after extensive decompression at the L3/4 or L4/5 levels. The implant limits extension, coronal translation, anterior translation, and axial rotation. However, posterior translation is not limited as no posterior constraint is present. Indications for use include grade I spondylolisthesis, degenerative facet arthrosis, with or without instability and spinal stenosis. Load-Sharing by Posteriorly Stabilized Spinal Segments Posterior spinal implant constructs and the stabilized spinal segments act together and share spinal loads and moments. In flexion and extension, spinal loads are supported by an equal and opposite force coupled between the intervertebral disc and fixator rods, and in lateral bending, an equal and opposite force coupled between the right and left fixator rods [44]. Torsional forces were equally shared between the intervertebral disc, posterior elements, and the implants. Therefore, the anterior structures play a vital role in the overall load- bearing function of the stabilized spine and in the case of severe anterior column injuries additional anterior support is critical to prevent failure of the posterior instrumentation (Fig. 11).

Anterior Instrumentation Anterior stabilization techniques offer excellent visibility, allowing better decompression of the anterior spinal canal, reconstruction of the anterior column, and restoration of lumbar lordosis. Numerous systems have been developed for the thoracolumbar spine, including screw-rod systems and interbody cages.

Screw-Rod Systems Pioneered by Dwyer in 1969 and modified by Zielke in 1975, rigid anterior screwrod fixation systems are relatively low in profile and are designed for the anterior column. They transfer load through a combination of compressive and tensile loading along the length of the implant, or through bending and torsion of the implant itself. Single-rod constructs achieve stability in lateral bending and flexion, but torsional stability requires a double-rod construct, with the possible addition of a cross connector. In lateral bending the implant acts as a tension band device, providing better stabilization when the patient bends away from the side of the implant. Systems using locking screws and plates also provide a stiffer construct [45].

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Fig. 11 Example of an unstable L1 burst fracture with flexion distraction, posterior column bony ligamentous injury, and significant canal compromise. This was treated in two stages: (1) posterior realignment with T11 to L3 instrumentation (polyaxial pedicle screws and rods) and (2) anterior column reconstruction (support) with direct decompression of the canal (removal of the retropulsed fragments) using a titanium expandable cage (vertebrectomy via an 11th rib retropleural retroperitoneal approach)

Intervertebral Cages Intervertebral cages were developed to increase interbody fusion and restore anatomical alignment. Cages augment spinal arthrodesis by reconstructing the anterior column and restoring the height of the disc space, thereby providing mechanical support to the segment being fused and allowing the use of bone graft within the cage to promote fusion. Brantigan and Steffee, first described the use of interbody

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implants in 1993 and reported successful fusion in all 26 patients after the use of a carbon-fiber reinforced polymer implant with pedicle screw fixation [46]. Prior to this, fashioned allograft and autograft bone blocks were used. Several other designs have since been developed including static, expandable, threaded, and screw-cage types, which are constructed from a variety of biocompatible materials (Fig. 12). In the lumbar spine, cages must be strong enough to withstand significant loads of over 7000 N without failure of the implant. Adequate support from the vertebral endplates is also necessary to prevent implant subsidence. Oxland and Lund [50] biomechanically tested three different stand-alone cage designs (porous titanium cage, rectangular carbon-fiber cage, and cylindrical threaded titanium cage) and reported that all cages provided stability in lateral bending and flexion, whereas none of the cages offered support in extension and axial rotation [47]. Three-dimensional stabilization was only achieved with the addition of posterior instrumentation. Anjarwalla

Fig. 12 (a–d) Examples of expandable vertebrectomy/corpectomy cages. (a) titanium expandable cage (b) PEEK expandable cage with fixable endplates (c) Case illustrating L3 vertebrectomy using a titanium expandable cage with large fixable endplates, posterior pedicle screws and rods with crosslink connector (d) Case illustrating L5 vertebrectomy using a titanium expandable cage, posterior pedicle screws and rods with crosslink connector and iliac screws (note the use of an antikick plate and the importance of planning for lordosis). (Images courtesy of Globus Medical Inc.)

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et al. also reported a significant increase in interbody fusion rates (51% vs. 89%) with the addition of posterior pedicle screw fixation, when compared to a stand-alone anterior lumbar interbody fusion (ALIF) procedure [48]. Based on the importance of posterior stability in the success of interbody devices, newer designs have combined the principle of interbody cages with that of an anterior tension band instrumentation. The advantage of these stand-alone locking screw-cage constructs is that the procedure is performed through a single anterior approach, which preserves the posterior elements. Choi et al. compared the biomechanics of stand-alone interbody cages to that of interbody cages with additional pedicle screw fixation and demonstrated that stand-alone cages provided sufficient stability, distributed loads in a manner similar to an intact spine and reduced stress in adjacent levels [49].

Intervertebral Disc Replacement Designed by Schellnack and Buttner-Janz in the 1980s, intervertebral disc replacements aim to restore disc height and relieve pain without restricting motion. The two main design concepts include unconstrained and semi-constrained types. Unconstrained devices have a mobile axis of rotation and can compensate for minor errors in device placement. Allowing translation reduces the stress concentration at specific points on the bearing surface, but as this device type relies on the surrounding structures to provide resistance to extremes of motion, this leads to greater facet joint stresses with a risk of early degeneration. Semi- constrained disc implants share a larger part of the load bearing which may protect the facet joints from early degeneration. However, as these devices have a fixed axis of rotation, they are less forgiving and need exact anatomic placement. Utilization rates for lumbar disc replacement have remained low over the last decade despite initial enthusiasm from surgeons. The current literature has mainly attributed this to historical shortcomings, biomechanical concerns regarding wear debris and device failure, narrow indications for use, and a challenging surgical technique with a long learning curve [50]. Hybrid Constructs Hybrid constructs were developed as a technique for managing symptomatic multilevel degenerative disease in younger patients. By preserving segmental motion, they aim to overcome complications of multilevel fusion surgery, including ASD. Various implant combinations have been described in the literature, although overall success has varied. Aunoble et al. reported improvements in disability index scores and back pain at two years post-surgery with hybrid fusion (ALIF on one level and total disc arthroplasty at another), in comparison to two-level disc arthroplasty and two-level fusion [51]. Andrieu et al. reported equivalent results between two-level disc arthroplasty and hybrid constructs at two years post-surgery [52]. Anterior Vertebral Body Tethering Pioneered by Newton in 2011, anterior vertebral body tethering aims to create a more normal spinal contour while preserving functional motion in children with scoliosis.

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The implant acts as an internal mechanical restraint and harnesses the child’s remaining spinal growth to reduce the deformity. In principle, vertebral body tethering may delay or eliminate the need for a definitive fusion procedure. However, the indications remain controversial with high rates of implant failure and other significant complications reported in the current literature [53].

Conclusion The lumbar spine plays a key role in supporting the upper spine and allowing range of motions. However, problems may arise from improper posture during heavy lifting or performing activities in daily living, resulting in higher incidences of back pain and disc degenerative disease. A sound knowledge of the biomechanics is therefore necessary to enable a better understanding of the factors that influence the clinical problems and their remedy.

References 1. Louis R. Functional anatomy of the lumbar spine. In: Brock M, Mayer HM, Weigel K, editors. The artificial disc. Berlin/Heidelberg: Springer; 1991. p. 3–11. 2. Laouissat F, Sebaaly A, Gehrchen M, Roussouly P. Classification of normal sagittal spine alignment: refounding the Roussouly classification. Eur Spine J. 2018;27(8):2002–11. 3. Roussouly P, Pinheiro-Franco JL. Sagittal parameters of the spine: biomechanical approach. Eur Spine J. 2011;20(Suppl 5):578–85. 4. Junghanns H. Die Zwischenwirbelscheiben in Rontegenbild. Fortschr Roentgenstr. 1931;43: 275–305. 5. Grobler LJ, Robertson PA, Novotny JE, Pope MH. Etiology of spondylolisthesis. Assessment of the role played by lumbar facet joint morphology. Spine. 1993;18(1):80–91. 6. White AA, Panjabi MM. Clinical biomechanics of the spine. 2nd ed. Philadelphia: J.B. Lippincott; 1990. 7. Adams MA, Bogduk N. The biomechanics of back pain. Edinburgh: Churchill Livingstone; 2002. p. 121–3. 8. Cyron BM, Hutton WC. The tensile strength of the capsular ligaments of the apophyseal joints. J Anat. 1981;132:145–50. 9. Wong DA, Transfeldt E. Macnab’s backache. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2007. 10. Panjabi MM, Goel VK, Takata K. Physiologic strains in the lumbar spinal ligaments. Spine. 1982;7:192–203. 11. Pintar FA, Yoganandan N, Myers T, Elhagediab A, Sances A Jr. Biomechanical properties of human lumbar spine ligaments. J Biomech. 1992;25(11):1351–6. 12. Tkaczuk H. Tensile properties of the human lumbar annulus fibrosus. Thesis. Acta Orthop Scand. 1968;(Suppl 115):1. 13. Wilke HJ, Wolf S, Claes LE, Arand M, Wiesend A. Stability increase of the lumbar spine with different muscle groups: a biomechanical in vitro study. Spine. 1995;20(2):192–8. 14. Gardner-Morse MG, Stokes IAF. The effects of abdominal muscle coactivation on lumbar spine stability. Spine. 1998;23(1):86–92. 15. Kuo CS, Hu HT, Lin RM, Huang KY, Lin PC, Zhong ZC, Hseih ML. Biomechanical analysis of the lumbar spine on facet joint force and intradiscal pressure – a finite element study. BMC Musculoskelet Disord. 2010;11:151.

1892

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16. Kraemer J. History and terminology. Intervertebral disk diseases – causes, diagnosis, treatment and prophylaxis, Ch 2. 3rd ed. New York: Thieme Medical and Scientific Publishers Private Ltd; 2009. p. 12. 17. Takahashi I, Kikuchi S, Sato K, Sato N. Mechanical load of the lumbar spine during forward bending motion of the trunk – a biomechanical study. Spine. 2006;31(1):18–23. 18. Nachemson A. Towards a better understanding of low-back pain: a review of the mechanics of the lumbar disc. Rheumatol Rehabil. 1975;14(3):129–43. 19. Wilke HJ, Neef P, Caimi M, Hoogland T, Claes LE. New in vivo measurements of pressures in the intervertebral disc in daily life. Spine. 1999;24(8):755–62. 20. Steffen T, Baramki HG, Rubin R, Antoniou J, Aebi M. Lumbar intradiscal pressure measured in the anterior and posterolateral annular regions during asymmetrical loading. Clin Biomech (Bristol, Avon). 1998;13(7):495–505. 21. Lovett RW. The mechanism of the normal spine and its relation to scoliosis. Boston Med Surg J. 1905;13:349–58. 22. Choi SJ, Moon JW, Ryu D, Oh CH, Yoon SH. Range of motion according to the fusion level after lumbar spine fusion: a retrospective study. Nerve. 2018;4(2):55–9. 23. Fujii R, Sakaura H, Mukai Y, Hosono N, Ishii T, Iwasaki M, Yoshikawa H, Sugamoto K. Kinematics of the lumbar spine in trunk rotation: in vivo three-dimensional analysis using magnetic resonance imagine. Eur Spine J. 2007;16:1867–74. 24. Steffen T, Rubin RK, Baramki HG, Antoniou J, Marchesi D, Aebi M. A new technique for measuring lumbar segment motion in vivo. Method, accuracy and preliminary results. Spine. 1997;22(2):156–66. 25. Gallagher S, Marras WS, Litsky AS, Burr D. An exploratory study of loading and morphometric factors associated with specific failure modes in fatigue testing of lumbar motion segments. Clin Biomech (Bristol, Avon). 2006;21(3):228–34. 26. Panjabi MM, Thibodeau LL, Crisco JJ 3rd, White AA 3rd. What constitutes spinal instability? Clin Neurosurg. 1988;34:313–39. 27. Friberg O. Lumbar instability: a dynamic approach by traction-compression radiography. Spine. 1987;12(2):119–29. 28. Varlotta GP, Lefkowitz TR, Schweitzer M, Errico TJ, Spivak J, Bendo JA, Rybak L. The lumbar facet joint: a review of current knowledge: part 1: anatomy, biomechanics, and grading. Skelet Radiol. 2011;40(1):13–23. 29. Adams MA, McNally DS, Dolan P. Stress distributions inside intervertebral discs: the effects of age and degeneration. J Bone Joint Surg Br. 1996;78:965–72. 30. St-Pierre GH, Jack A, Siddiqui MM, Henderson RL, Nataraj A. Nonfusion does not prevent adjacent segment disease: dynesys long-term outcomes with minimum five-year followup. Spine. 2016;41(3):265–73. 31. Halvorson TL, Kelley LA, Thomas KA, Whitecloud TS 3rd, Cook SD. Effects of bone mineral density on pedicle screw fixation. Spine. 1994;19(21):2415–20. 32. Cho W, Cho SK, Wu C. The biomechanics of pedicle screw-based instrumentation. J Bone Joint Surg Br. 2010;92:1061–5. 33. Send WRD, Chou SM, Siddiqui SS, Oh JYL. Pedicle screw designs in spinal surgery. Spine. 2018;44(3):E144–9. 34. Shepherd DL, Alvi MA, Murphy ME, Kerezoudis P, Corl F, Hitchon PW, Nassr A, Bydon M. The cortical bone trajectory for lumbar spine fusion. Oper Tech Orthop. 2017;27:269–74. 35. Rohlmann A, Calisse J, Bergmann G, Weber U. Internal spinal fixator stiffness has only a minor influence on stresses in the adjacent discs. Spine. 1999;24(12):1192–5. 36. Krag MH. Biomechanics of thoracolumbar spinal fixation: a review. Spine. 1991;16(Suppl 3): S84–99. 37. Mohammed N, Patra DP, Narayan V, Savardekar AR, Dossani RH, Bollam P, Bir S, Nanda A. A comparison of the techniques of direct pars interarticularis repairs for spondylolysis and low-grade spondylolisthesis: a meta-analysis. Neurosurg Focus. 2018;44(1):E10.

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38. Lakshmanan P, Ahuja S, Lewis M, Howes J, Davies PR. Transsacral screw fixation for highgrade spondylolisthesis. Spine J. 2009;9(12):1024–9. 39. Collados-Maestre I, Lizaur-Utrilla A, Bas-Hermida T, Pastor-Fernandez E, Gil-Guillen V. Transdiscal screw versus pedicle screw fixation for high-grade L5-S1 isthmic spondylolisthesis in patients younger than 60 years: a case-control study. Eur Spine J. 2016;25:1806–12. 40. Yu BS, Zhuang XM, Zheng ZM, Li ZM, Wang TP, Lu WW. Biomechanical advantages of dual over single iliac screws in lumbo-iliac fixation construct. Eur Spine J. 2010;19:1121–8. 41. Wu AM, Chen D, Chen CH, Li YZ, Tang L, Phan K, et al. The technique of S2-alar- iliac screw fixation: a literature review. AME Med J. 2017;2:179. 42. Tai CL, Chen LH, Lee DM, Liu MY, Lai PL. Biomechanical comparison of different combinations of hook and screw in one spine motion unit – an experiment in porcine model. Musculoskelet Disord. 2014;15:197. 43. Landi A. Interspinous posterior devices: what is the real surgical indication? World J Clin Cases. 2014;2(9):402–8. 44. Cripton PA, Jain GM, Wittenberg RH, Nolte LP. Load-sharing characteristics of stabilized lumbar spine segments. Spine. 2000;25(2):170–9. 45. Wilke HJ, Kemmerich V, Claes LE, Arand M. Combined anteroposterior spinal fixation provides superior stabilisation to a single anterior or posterior procedure. J Bone Joint Surg Br. 2001;83(4):609–17. 46. Brantigan JW, Steffee AD. A carbon fibre implant to aid interbody fusion: two-year clinical results in the first 26 patients. Spine. 1993;18:2106–7. 47. Oxland T, Lund T. Biomechanics of stand-alone cages and cages in combination with posterior fixation: a literature review. Eur Spine J. 2000;9(suppl 1):S95–S101. 48. Anjarwalla NK, Morcom RK, Fraser RD. Supplementary stabilisation with anterior lumbar intervertebral fusion – a radiologic review. Spine. 2006;31:1281–7. 49. Choi KC, Ryu KS, Lee SH, Kim YH, Lee SJ, Park CK. Biomechanical comparison of anterior lumbar interbody fusion: Stand-alone interbody cage versus interbody cage with pedicle screw fixation – a finite element analysis. BMC Musculoskelet Disord. 2013;14:220,1–9. 50. Salzmann SN, Plais N, Shue J, Girardi FP. Lumbar disc replacement surgery – successes and obstacles to widespread adoption. Curr Rev Musculoskelet Med. 2017;10:153–9. 51. Aunoble S, Meyrat R, Al Sawad Y, Tournier C, Leijssen P, Le Huec JC. Hybrid constructs for two levels disc disease in lumbar spine. Eur Spine J. 2010;19:290–6. 52. Andrieu K, Allain J, Longis PM, Steib JP, Beaurain J, Delecrin J. Comparison between total disc replacement and hybrid construct at two lumbar levels with minimum follow- up of two years. Orthop Traumatol Surg Res. 2017;103(1):39–43. 53. Newton PO. Spinal growth tethering: indications and limits. Ann Transl Med. 2020;8(2):27.

Bioengineering of Spinal Implants

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Christopher John Gerber, Anindya Basu, and Selvin Prabhakar Vijayan

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bioengineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spinal Anatomy and Biomechanics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Current Concepts of Bioengineering in Spine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Biomaterials and Implant Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pedicle Screws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . New Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

Bioengineering encompasses knowledge from several pure and applied sciences which are used in medical devices, diagnostic equipments, and various medicinerelated fields. Though concept of bioengineering existed for many years, acknowledgement and significant advancements in this field started after 1950s. One of the main contributions of bioengineering in field of spine surgery has been towards development of various materials and designs of implants. For application of bioengineering principles in implantology, basic understanding of clinical biomechanics is necessary. Since late 1800s, spinal surgery implants have undergone a constant evolution with newer materials. Implant designs are being developed which are more biostable, biocompatible, and improve surgical outcomes in terms of motion preservation, early fusion, and longevity of implants. Different biomaterials and spinal implant designs with advantages and disadvantages for each material and their applications are discussed further in this chapter.

C. J. Gerber · A. Basu (*) · S. P. Vijayan Institute of Neurosciences Kolkata, Kolkata, India e-mail: [email protected]; [email protected]; [email protected] © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_100

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Keywords

Bioengineering · Biomaterials · Biomechanics · Spine implant · Cages · Rods · Pedicle screws · Plates · Hooks · Wires · Disc replacement · Vertebral body tethering

Introduction Spine surgery is a constantly evolving branch of medicine where the use of implantable materials is very common. Approximately 2 lakh spine surgeries are being done in India per year and the number is only steeply rising with time. In a considerable number of spine surgeries implants are used. The biocompatibility and reaction to bodily stress of these implants and the materials have to be taken into consideration. Spinal surgery is therefore an ideal situation for the application of bioengineering which has played an important role in development and designing spinal implants. Bioengineering is the application of the life sciences, physical sciences, mathematics, and engineering principles to define and solve problems in biology, medicine, health care, and other fields. Bioengineering is a relatively new discipline that combines many aspects of traditional engineering fields such as chemical, electrical, and mechanical engineering. It uses traditional engineering principle and techniques and applies them to real-world biological and medical problems [1, 2].

Bioengineering The practice of biomedical engineering has a long history. One of the earliest examples is a wood and leather prosthetic toe found on a 3,000-year-old Egyptian mummy. Medical equipment such as a stethoscope was first thought of in 1816 when a physician used a rolled-up newspaper to listen to a heart. Bioengineering as a field of science had less recognition before World War II. The double-helix structure of DNA found by Watson and Crick (1953) brought huge recognition to this field. Biomechanics was coined by British scientist Heinz Wolff in 1954 at National Institute for Medical Research. It was first time a department for bioengineering was formed in a university [3]. Biomedical engineering has evolved over the years in response to advancements in science and technology. Throughout history, humans have made increasingly more effective devices to diagnose and treat diseases and to alleviate, rehabilitate, or compensate for disabilities or injuries.

Spinal Anatomy and Biomechanics Some important components of spinal column include vertebrae and joints between them, neural structures, discs, and ligamentous structures. A brief note about them has been discussed.

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Spinal column consists 33 vertebrae – 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal. It has four curvatures, thoracic and sacral are kyphotic, called the primary curves which are present from in utero. Cervical and lumbar are lordotic curves which develop postnatally and help in erect posture of humans. Vertebra gives the structural strength to spinal column and plays the most important function of protecting the neural structures. There are 23 discs between C2 and S1. It has four components, outer alternating layer of collagen fiber forming peripheral rim with fibro cartilage which form annulus fibrosis, central nucleus pulposus, and two cartilaginous end plates. They are avascular structures in an adult. The play the important function of shock absorption and they account for one-third to one-fifth of total height of spinal column. The ligaments around spinal column help restrict excessive motion; some important ligaments are discussed here. ALL (anterior longitudinal ligament) begins at occiput as anterior occipitoatlantal membrane and extends up to sacrum. PLL (posterior longitudinal ligament) begins at C2, extends up to sacrum. It adheres closely to disc annulus. Ligamenta flava are broad paired ligaments arising from ventral surface of caudal lamina and attach to dorsal border of adjacent rostral lamina, laterally to joint capsules which are present from C1C2 up to L5S1. Interspinous ligaments attach from base to tip of each spinous process, while supraspinous ligament is continuation of ligamentum nuche at neck, contacting spinous process at their tip. They end between L3 and L5. Clinical biomechanics refers to understanding of normal and pathological functions of human vertebral column due to application of deforming force. Spinal column resist external mechanical forces by undergoing internal deformation, which depend on the type of vector force applied. The common types are flexion, extension, subluxation, rotation, and distraction. Due to anatomic characteristics spine is constantly acted by compressive force, usually flexion which is restricted by vertebral body. Several other factors contribute to this stability including facet joints, pedicle, intervertebral disc, ligaments, and muscles. Few of these characteristics have been discussed here. Facet joints do not substantially support axial loads. They are in coronal orientation at cervical spine, intermediate at thoracic and sagittal at lumbar spine. Hence each region has variable resistance for different vectors, like lumbar region has more resistance for rotational force. Any load resisted by vertebral body ends up transferred to disc. Because of its flexibility it can resist compression, tension, shear, bending, and torsion forces. Usually lumbar spine discs have maximum load resistance and average failure torque of healthy disc is 25% higher than degenerated disc. The spinal ligaments act as uniaxial structures on direct tensile load. Generally, ligaments with longer lever arm, i.e., farther away from IAR (instantaneous axis of rotation), contribute more for stability and those on convex side of spinal curvature are stronger [4].

Current Concepts of Bioengineering in Spine One of the main contributions of bioengineering in field of spine surgery has been towards development of various materials and designs of implants for internal fixation and fusion. We will have a brief discussion on it.

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Biomaterials and Implant Designs History of spinal surgery dates back to 1839 when Jules Gerin first attempted surgical scoliosis correction [5]. Dr. Berthold Earnest Hadra in the late 1800s used silver wire to fix C6–7 dislocations [6]. These were the first steps from where birth and evolution of spinal implants had started. Since then, spinal implants have undergone a constant evolution, incorporating the improving knowledge of the spinal biomechanics, and to use new technologies and materials. Most important factors for materials used in spinal implants are biostability (microorganism resistance) and biocompatibility (inertness to living tissue). An optimal material is one with an appropriate Young’s modulus, stiffness, and fatigue [7]. Materials most commonly used include stainless steel (SS), titanium, cobalt chrome, nitinol (a nickel titanium alloy), tantalum, and polyetheretherketone (PEEK). Ideal biomaterial should be biologically inert/compatible, have a Young’s modulus similar to that of the bone, high tensile strength, stiffness, fatigue strength, and low artifacts on imaging specially magnetic resonance imaging. We will further discuss the uses of these various biomaterials and design spinal implants with advantages and disadvantages for each material and their applications. 1. Cages: Cages are spinal implants that help in uniformly distributing force between vertebral bodies by acting as structural support and also to restore the height of the intervertebral foramina [8]. Common materials used for manufacturing cages are metal – ranging from pure titanium, titanium composite/alloy, and ceramic – usually silicon nitride, or plastic – usually PEEK (Polyetheretherketone) or another bioinert plastic such as acrylic by itself or coated in another material (such as hydroxyapatite [HA] or titanium) [9]. These cages typically have hollow space, which allows filling with bone graft aiding in bony fusion between the vertebrae. Specially designed cages also help in restoring lordosis, specially at lumbar and cervical spine. The most popular materials used today are titanium (titanium-aluminum-vanadium, Ti6Al4V alloy) and PEEK (Tables 1 and 2) [10]. Titanium and its alloys (Figs. 1 and 2) are commonly used over SS and cobalt because of their high fracture resistance, a superior biocompatibility, corrosion resistance, and Young’s modulus [11]. PEEK has a similar Young’s modulus compared to bone (Fig. 3), but has weak surface interfaces that can fracture upon cage implantation [12]. PEEK cages (Fig. 4) have radiopaque wires that help surgeons to locate them with image intensifiers. PEEK implant is hydrophobic by nature and does not bind to bone-like metallic implants. On review of various studies comparing fusion rates, the fusion rates are higher with titanium than PEEK but were not statistically significant and there is increased subsidence rate with the former. It has also been shown that PEEK has a significantly lower stress compression strength compared to titanium (2.5 times weaker) [13]. PEEK cages are advantageous over titanium cages in anterior cervical discectomy and fusion (ACDF) surgeries, with lower loss of Cobb angles and lower cage subsidence rate [14]. Researchers are trying to find out more biocompatible material than titanium and PEEK to improve bony fusion.

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Table 1 Common biomaterials used in spine surgery Implant Cage

Implementation procedure Anterior/Posterior interbody fusion

Screws

Pedicle screw fixation

Rods

Spinal fusion

Plates

Spinal stabilization

Standard material Titanium PEEK Ceramic Acrylic Titanium (Ti6Al4V) doped with: HA CaP ECM Tantalum Titanium CoCr PEEK Stainless steel Nitinol Titanium

Upcoming materials Bioactive glass Silicon nitride Apatite-wollastonite Poly(E-caprolactone) þ HA (biodegradable) Carbonated apatite

Ti-Mo Oxygen-modified beta-type Ti-Cr Biodegradable materials

Biodegradable materials

DDD degenerative disk disease, PEEK polyetheretherketone, Ti6Al4V titanium-aluminium-vanadium, HA hydroxyapatite, CaP calcium phosphate, ECM extra-cellular matrix, CoCr cobaltchromium alloys, TiMo titanium-molybdenum, TiCr titanium-chromium

Materials like silicon nitride (Si3N4) and apatite-wollastonite (A/W) ceramic did not show significant difference compared to PEEK [15]. Some of the computational and in vitro modelling studies performed on porous biodegradable materials such as poly(ε-caprolactone) combined with HA showed promising results but till date no data in human trials are available for these materials [16]. Expandable cages (Figs. 5 and 6) are new design implants used in corpectomy surgery. Once the cage is placed, they can be expanded, thus helps in restoring the sagittal alignment by increasing lordosis. Cages used in OLIF, XLIF, and similar procedures are mostly made of PEEK with radiopaque markers. They are shaped like a bullet for easy insertion, hence called bullet cages (Fig. 7). They are either flat or with lordotic options ranging from 0
to 18
, in 6
increments per cage per level. These surgical methods are also used in adult degenerative deformity correction, where the cages also help in coronal deformity correction up to 45% alone and up to 64% when combined with pedicle screws. 2. Rods: Spinal rods are used in conjunction with other spinal implants to add stability to spinal implant structure. In 1962, Dr. Harrington introduced the “Harrington Rod” – an SS rod – for surgical treatment of scoliosis [17]. Initially rods were made of SS but currently titanium is more popular due to improved biomechanical, biocompatibility properties, and improved stress shielding of pedicle instrumentation. The metal rods used today are made of three types of

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Table 2 Characteristics of biomaterials Material Stainless steel

Titanium

PEEK

CoCr

Ceramic

Nitinol

Tantalum

Advantages Very strong Very stiff Easily doped/ alloyed to be stronger Inexpensive Lightweight Strong Flexible Biocompatible Easily doped/ alloyed to be stronger Lightweight Flexible Biocompatible Relatively inexpensive Easily doped/ coated for improved grafting Low artifacts on imaging Strong Flexible Biocompatible Relatively inexpensive Biocompatible Water resistant Easily doped Strong “Memory Metal” (shape recovery) High frictional characteristics Low Young’s modulus

Disadvantages Corrosion Relatively poor biocompatibility High artifacts in imaging

Application Scoliosis correction(rods) Formerly used in screws; now mostly replaced by titanium

Relatively expensive Some artifacts during imaging

Screws Rods Plates Cages

Low Young’s modulus Some grafting issues, but improved with coating

Rods Cages Disk replacement

Relatively expensive High artifacts on imaging

Adolescent scoliosis correction (rods) to provide a more flexible buttress for the spine to curve about

Brittle

Used in cage biomaterials

Grafting issues but can be improved with coating/doping

Doped with A/W

Relatively expensive Sometimes not stiff enough for proper correction Very expensive

Not frequently used, but can be implemented for young scoliosis correctional surgery

Not stiff enough for some spinal corrections

Has primarily been phased out completely by titanium

Not frequently used due to its price

PEEK polyetheretherketone, Co-Cr cobalt-chromium alloys, A/W apatite-wollastonite

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Fig. 1 Titanium ACDF cage

Fig. 2 Titanium mesh cage

alloy: iron (Fe)-chromium (Cr)-nickel (Ni) alloys and austenitic SS, titanium and its alloys (PTi and Ti6Al4V alloy), and cobalt-chromium alloys (CoCr) (Fig. 8). CoCr rods have gained recent popularity of late due to increased rigidity which helps in better correction of stiff curves and also restore thoracic sagittal

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Fig. 3 Elastic modulus of various biomaterials compared to cortical and cancellous bone Fig. 4 PEEK cage

alignment compared to titanium rods [18]. Although CoCr compared to titanium shows increased artifacts on MRI, a study has shown that the spinal canal and neural element analysis was not affected by the CoCr artifacts. Nitilol (50% Ni and 50% Ti) rods are on the rise but have not gained popularity because of high cost and lower Young’s modulus compared to Ti or SS rods [19]. PEEK rods (Fig. 9) have also been tried recently. Despite its advantage of fewer artifacts in MRI they have not gained popularity due to high failure rates, pseudo-arthrosis,

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Fig. 5 Expandable cage with screws

Fig. 6 Expandable cage without screw

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Fig. 7 PEEK bullet cage

Fig. 8 Rods (titanium and cobalt chromium) Fig. 9 PEEK rods

and difficulty in identifying failure in X-ray [20]. New research on beta-type titanium-molybdenum and oxygen-modified beta-type titanium-chronium alloys have demonstrated promising Young’s moduli, high bending strength, and high tensile strength [21]. Attempts to develop biodegradable rods were also done but studies with biodegradable rods demonstrated that they could withstand significant dynamic compression cycles under standard axial load but have a 20% and 80% decrease in Young’s modulus after 6 months and 12 months, respectively [22]. Since these studies were not done in human trials or under true biological conditions, not all the effects of wear and tear of the abovementioned materials could be measured and tested.

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Fig. 10 MAGEC rods

Recently a magnetically controlled growing rod system called MAGEC (magnetic expansion control) (Fig. 10) was introduced in early-onset scoliosis surgery in pediatric patients having substantial growth remaining. In MAGEC rods, lengthening of the two magnetic telescoping rods are done under the control of an externally applied magnetic remote control device every 3–6 months as a non-invasive outpatient procedure. This reduces the complications related to recurrent surgery, decreases exposure to anesthesia, decreases the overall costs, and improves the health-related quality of life of the patients. MAGEC rods are costly compared to traditional growing rods and have been reported to cause metallosis [23].

Pedicle Screws Pedicle screw is the gold standard implantation technique in majority spinal surgeries because they offer three column fixations. Currently preferred material for pedicle screws is titanium. Traditionally the screws are cylindrical, solid with single-thread profile. Currently there are different screw shapes (cylindrical and conical) (Fig. 11), different thread profiles (fine thread, coarse thread, and dual thread) (Fig. 12), expanding screws, and cannulated screws with polymethylmethacrylate (PMMA) cement augmentation. These developments are aimed to increase pullout strength of screws, thus giving more stable construct. Fine threaded screws, like cortical screws, help get purchase from cortical bone of pedicle, coarse-threaded screws from cancellous bone of body, and dual thread have proximal fine and distal coarse thread to enhance purchase from both cortical and cancellous screws. Expandable screws (Fig. 13) once inserted into bone have flanges opening up at the tip, increasing bone purchase. Cement augmentation of screws are done by using solid screws with cement prefilling or cannulated screws in which cement is injected through screw after insertion. The screw shape and thread profile are considered important factors of the screw fixation strength. Dual-core/dual-

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Fig. 11 Pedicle screw: A – cylindrical, B – conical

Fig. 12 Type 1 coarse thread, 2- fine thread, 3 and 4 variable thread

thread screws have more pullout strength than single-thread screws. Similarly expandable screws and cement-augmented screws all increase the pullout strength compared to solid non-augmented screws and are especially helpful in poor bone density cases [25]. Pedicle screws have evolved constantly since their introduction and resent researches are focused on surface coating materials like hydroxyapatite (HA), calcium phosphate (CaP), polymethymethacrylate bone cement (PMMA-BC), extra-cellular matrix (ECM), tantalum, and titanium plasma spray. Studies on HA- and CaP-coated screws have not shown conclusive evidence supporting their superiority compared to uncoated screws, on the other hand PMMA-BC screws have shown significant increase in pullout strength compared to uncoated screws [26]. Newer studies are evaluating the efficacy of ECM and tantalum coating over titanium screws with some studies showing positive results. Initially pedicle screws were monoaxial, later polyaxial were introduced and gained popularity due to ease in road seating into screw head. Polyaxial pedicle screw shows less adjacent segment degeneration compared to the monoaxial pedicle screws due to lower von Mises stress [27] (Fig. 14). Uniplanar or uniaxial screw was designed to accommodate sagittal angle variation of the pedicle

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Fig. 13 Expandable screw

Fig. 14 Types of screw head

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Fig. 15 Apifix system

screws. They are mostly placed in apex of scoliotic curves as they allow better derotation compared to polyaxial screws. Bending, breakage, and pullout are most common implant-related complications [28] for pedicle screw usage and these are affected by screw diameter, screw length, insertional depth, orientation, and cross-link conduits [29]. Patient- and procedure-related factors affecting screw pullout strength include osteoporosis, cortical fixation, pedicle morphology, screw orientation, bone density, screw thread area, and screw orientation [30]. Latently, fusionless scoliosis correction using periapical distraction systems (Apifix) (Fig. 15) has been developed. The periapical distraction system is a new, less invasive system that connects two periapical pedicle screws through polyaxial mobile ball-and-socket joints with a rod. It is indicated for adolescent idiopathic scoliosis patients with deformity of a Cobb angle up to 60
and flexible major and secondary curves.

Plates Spinal plates are mostly used in anterior approach in cervical spine, as well as anterolateral approach in dorsal and lumbar spine. The thickness of plate plays an important role as high-profile plate causes irritation to larynx and oesophagus leading to dysphagia. Plates with mechanism for screws heads to be locked with plates are called locking plates (Fig. 16). They give increased stability to the construct. The plates in which angle of locking screws can be changed are called variable angle screw plates. Newer research is on biodegradable plates, with in vitro studies showing promising results. Mini-plate systems (Fig. 17) are extensively applied to secure the posterior elements in cervical and dorsal laminoplasty [31]. Lateral lumbar plates (Fig. 18) used in OLIF and similar surgeries are low profile, pre-contoured plates with either 2 or 4 variable angle locking screw fixation options. The novel concept of lateral lumbar fixation through reverse pedicle screw (RPSF) fixation is by directing the trajectory of superior screws at 20–30
upwards towards the contralateral pedicle and of inferior screws were directed parallel to the upper end plate towards the contralateral pedicle [32]. 5. Hooks and wires:Sublaminar wires (Fig. 19) are the oldest spinal anchoring implants and have been used in conjunction with Luque–Harrington rods. Although

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Fig. 16 Plates with locking screw option

Fig. 17 Mini plates

they require sublaminar dissection, the wire and cable systems offer simplicity without the need for intraoperative fluoroscopy. When used in conjunction with Harrington distraction rods, sublaminar wires have been shown to increase torsional and lateral bending stability. Monofilament and braided wires are now available in

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Fig. 18 Lateral lumbar plates

Fig. 19 Sublaminar wires

both steel and titanium. Recently sublaminar bands have been introduced, the ends of which were secured around the fusion rod in a knot. These bands are either made of nylon or ultrahigh molecular weight polyethylene. In early 2000s, universal clamp (UC) with polyethylene terephthalate (PET) band (Fig. 20) was developed which provides stable fixation to the bone while applying less stress and permitting application of greater reduction forces [33]. Hooks, which appeared in 1953 for use with Harrington instrumentation, were gradually modified and diversified for adaptation to the sites of attachment. The currently available pedicular, laminar, and transverse process hooks (Fig. 21) were developed for Cotrel-Dubousset instrumentation [34]. Usage of hooks has drastically reduced following pedicle screw invention and in todays practice hooks are used as a bailout or reserve technique in pedicles deemed too small to allow engagement by screws or in pedicles with no hold due to some pathology or previous instrumentation. The hooks are usually made of titanium. Sublaminar hooks used over lamina can be right or left sided with front or side opening design. Angled hooks are used for anchorage over transverse process. Pedicle hooks are anchored to the pedicle after removing a small portion of the inferior facet and fixed with 3.2 mm screws passing in a cephalic direction towards end plate. Biomechanical studies of the different implants demonstrated maximum pullout strength of pedicle screws followed by hooks followed by wires.

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Fig. 20 Universal clamp with polyethylene terephthalate band

Fig. 21 Pedicle, laminar hooks

New Developments 1. Lumbar Spine Disc Replacement/Total disc replacement (TDR) The first lumbar disc replacement was in 1960, over next several decades lot of research work related to implantology related to artificial lumbar disc were done and implant systems developed. One such new-generation implant was ProDiscL which is made of a cobalt-chromium-molybdenum with an ultrahigh molecular weight polyethylene combined with a rough titanium surface coating to promote bone growth alloy [36]. Over the last decade a number of lumbar disc replacement surgeries have gone down significantly due to several studies showing poorer clinical results compared to fusion surgery. 2. Cervical Spine Disc Replacement Since it was first described in 1958 by Smith and Robinson, anterior cervical fusion is now common spine surgery and has excellent outcomes. Though anterior cervical discectomy and fusion (ACDF) is a successful procedure, it leads to increased biomechanical stress at adjacent segments causing degeneration. In the

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1980s, British neurosurgeon Brian Cummins wanted to solve this problem of adjacent segment degeneration and developed a ball-and-socket prosthetic made of steel for use in the cervical spine called the Bristol/Cummins disc. Basic design of artificial cervical discs usually has three parts, two metal plates resting on end plates and a plastic central core for articulation. Later titanium-coated disc plates were developed to increase bony integration. New-generation implant like the Mobi-C disc has superior and inferior cobalt chromium molybdenum alloy end plates coated with plasma-sprayed titanium and hydroxyapatite coating, and a polyethylene mobile bearing insert. Disc replacement preserves the motion at the operated level, reduce the rate of adjacent level pathology, and avoid any complications associated with pseudoarthrosis. Studies have demonstrated significant kyphosis correction as well as preservation of movement with replacement surgeries. Compared to the standard ACDF, in short-term studies artificial disc has demonstrated equal or increased improvement in range of motion, pain, and short-form scores and an improved neck disability index score, patient satisfaction, and reduced surgical intervention [37]. However, additional conclusive long-term clinical data is needed. 3. Vertebral Body Tethering Vertebral body tethering is a growth-modulating procedure for adolescent idiopathic scoliosis in patients approaching, or at the point of, their adolescent growth spurt. Under thoracoscopic visualization or using anterior approach, titanium vertebral body screws are placed on the convex side of a spinal curve. Then a polyethyleneterephthalate flexible cord is seeded through the screw heads. Tightening the cord compresses the adjacent screws and straightens the curve, which allows for slower curve progression, retention of growth potential, and freedom of spinal mobility and flexibility [35].

Conclusion To summarize, monumental change and growth has occurred in spine surgical implant in relation to both design and material since its invention. This would not have been possible without application of bioengineering in this field of medicine. Not only in field of implantology, but bioengineering concepts are also used to solve various other problems related to spine surgery like spinal cord injury, neuromonitoring, and recently 3D printing. Thus the importance and contribution of bioengineering is growing each day in spine surgery and thus helping both the surgeons and patients by helping to give better surgical outcome.

References 1. Abramovitz M. Biological engineering. Gale Virtual Reference Library; 2015. p. 10. ISBN 978-1-62968-5267. 2. Herold K, Bentley WE, Vossoughi J. The basics of bioengineering education. 26Th southern biomedical engineering conference. Maryland: College Park; 2010. p. 65. ISBN 9783642149979. 3. Medical & biological engineering. Oxford; New York: Pergamon Press. 1966–1976.

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4. Yoganandan N, Arun MWJ, et al. Practical anatomy and fundamental biomechanics. In: Michael P, Edward C, editors. Benzels spine surgery. Elseiver; 2017. p. 58–82. 5. Tarpada SP, Morris MT, Burton DA. Spinal fusion surgery: a historical perspective. J Orthop. 2017;14:134. 6. Hadra BE. The classic: wiring of the vertebrae as a means of immobilization in fracture and Potts’ disease. Berthold E. Hadra. Med Times and Register, Vol 22, May 23, 1891. Clin Orthop Relat Res. 1975;112:4–8. 7. Yoshihara H. Rods in spinal surgery: a review of the literature. Spine J. 2013;13:1350–8. 8. Merriwether M, Shockey, R, inventors; Box cage for intervertebral body fusion. United States patent. US1,9990,436,593.1999, November 09. 9. Farrokhi MR, Nikoo Z, Gholami M, et al. Comparison between acrylic cage and polyetheretherketone (PEEK) cage in single-level anterior cervical discectomy and fusion: a randomized clinical trial. Clin Spine Surg. 2017;30:38–46. 10. McGilvray KC, Easley J, Seim HB, et al. Bony ingrowth potential of 3D-printed porous titanium alloy: a direct comparison of interbody cage materials in an in vivo ovine lumbar fusion model. Spine J. 2018;18:1250–60. 11. Long M, Rack HJ. Titanium alloys in total joint replacement – a materials science perspective. Biomaterials. 1998;19:1621–39. 12. Kong F, Nie Z, Liu Z, et al. Developments of nano-TiO2 incorporated hydroxyapatite/PEEK composite strut for cervical reconstruction and interbody fusion after corpectomy with anterior plate fixation. J Photochem Photobiol B. 2018;187:120–5. 13. Vadapalli S, Sairyo K, Goel VK, et al. Biomechanical rationale for using polyetheretherketone (PEEK) spacers for lumbar interbody fusion-A finite element study. Spine (Phila Pa 1976). 2006;31:E992–8. 14. Chen Y, Wang X, Lu X, et al. Comparison of titanium and polyetheretherketone (PEEK) cages in the surgical treatment of multilevel cervical spondylotic myelopathy: a prospective, randomized, control study with over 7-year follow-up. Eur Spine J. 2013;22:1539–46. 15. Kersten R, Wu G, Pouran B, et al. Comparison of polyetheretherketone versus silicon nitride intervertebral spinal spacers in a caprine model. J Biomed Mater Res B Appl Biomater. 2019;107:688–99. 16. Kang H, Hollister SJ, La Marca F, et al. Porous biodegradable lumbar interbody fusion cage design and fabrication using integrated global-local topology optimization with laser sintering. J Biomech Eng. 2013;135:101013–8. 17. Harrington PR. Treatment of scoliosis. Correction and internal fixation by spine instrumentation. J Bone Joint Surg Am. 1962;44-A:591–610. 18. Serhan H, Mhatre D, Newton P, et al. Would CoCr rods provide better correctional forces than stainless steel or titanium for rigid scoliosis curves? J Spinal Disord Tech. 2013;26:E70–4. 19. Buehler WJ, Wang FE. A summary of recent research on the nitinol alloys and their potential application in ocean engineering. Ocean Eng. 1968;1:105–20. 20. Grob D, Benini A, Junge A, et al. Clinical experience with the Dynesyssemirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years. Spine (Phila Pa 1976). 2005;30:324–31. 21. Zhao X, Niinomi M, Nakai M, et al. Beta type Ti-Mo alloys with changeable Young’s modulus for spinal fixation applications. ActaBiomater. 2012;8:1990–7. 22. Tsuang FY, Hsieh YY, Kuo YJ, et al. Assessment of the suitability of biodegradable rods for use in posterior lumbar fusion: an in-vitro biomechanical evaluation and finite element analysis. PLoS One. 2017;12:e0188034. 23. Hickey BA, Towriss C, Baxter G, et al. Early experience of MAGEC magnetic growing rods in the treatment of early onset scoliosis. Eur Spine J. 2014;23(suppl 1):61–5. 24. Charroin C, Abelin-Genevois K, Cunin V, et al. Direct costs associated with the management of progressive early onset scoliosis: estimations based on gold standard technique or with magnetically controlled growing rods. Orthop Traumatol Surg Res. 2014;100:469–74. 25. Liu M-Y, Tsai T-T, Lai P-L, Hsieh M-K, Chen L-H, Tai C-L. Biomechanical comparison of pedicle screw fixation strength in synthetic bones: effects of screw shape, core/thread profile and cement augmentation. PLoS One. 2020;15(2):e0229328.

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26. Hasegawa T, Inufusa A, Imai Y, et al. Hydroxyapatite-coating of pedicle screws improves resistance against pull-out force in the osteoporotic canine lumbar spine model: a pilot study. Spine J. 2005;5:239–43. 27. Wang H, Zhao Y, Mo Z, et al. Comparison of short-segment monoaxial and polyaxial pedicle screw fixation combined with intermediate screws in traumatic thoracolumbar fractures: a finite element study and clinical radiographic review. Clinics (Sao Paulo). 2017;72:609–17. 28. Pfeiffer M, Hoffman H, Goel VK, et al. In vitro testing of a new transpedicular stabilization technique. Eur Spine J. 1997;6:249–55. 29. McKinley TO, McLain RF, Yerby SA, et al. The effect of pedicle morphometry on pedicle screw loading. A synthetic model. Spine (Phila Pa 1976). 1997;22:246–52. 30. Pfeiffer M, Gilbertson LG, Goel VK, et al. Effect of specimen fixation method on pullout tests of pedicle screws. Spine (Phila Pa 1976). 1996;21:1037–44. 31. Suda K, Abumi K, Ito M, et al. Local kyphosis reduces surgical outcomes of expansive opendoor laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976). 2003;28: 1258–62. 32. Sardhara J, Singh S, Mehrotra A, Bhaisora KS, Das KK, Srivastava AK, et al. Neuro-navigation assisted pre-psoas minimally invasive oblique lumbar interbody fusion (MI-OLIF): new roads and impediments. Neurol India. 2019;67:803–12. 33. de Gauzy JS, Jouve J-L, et al. Use of the Universal Clamp in adolescent idiopathic scoliosis. Eur Spine J. 2014;23(Suppl 4):S446–51. 34. Cotrel Y, Dubousset J, Guillaumat M. New universal instrumentation in spinal surgery. Clin Orthop Relat Res. 1988;227:10–23. 35. Betz RR, Kim J, D’Andrea LP, Mulcahey MJ, Balsara RK, Clements DH. An innovative technique of vertebral body stapling for the treatment of patients with adolescent idiopathic scoliosis: a feasibility, safety, and utility study. Spine (Phila Pa1976). 2003;28(suppl):S255–65. 36. Zigler JE, Delamarter R, Murrey D, et al. ProDisc-C and anterior cervical discectomy and fusion as surgical treatment for single-level cervical symptomatic degenerative disc disease: five-year results of a Food and Drug Administration study. Spine (Phila Pa 1976). 2013;38:203–9. 37. Lu H, Peng L. Efficacy and safety of Mobi-C cervical artificial disc versus anterior discectomy and fusion in patients with symptomatic degenerative disc disease: a meta-analysis. Medicine (Baltimore). 2017;96:e8504.

Allied Devices and Their Influence on Spinal Implants

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Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Image Guidance and Navigation Systems in Spine Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-Arm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Navigation Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tubular Retraction Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Retraction Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Intraoperative Neurophysiological Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Operating Room . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surgical Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surgical Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Endoscopy in Spine Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Microscope in Spine Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Thoracoscopy in Spine Surgery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Abstract

The improvement and evolution of allied devices in spinal surgery have led to improvement of spinal surgery implantology. Intraoperative images with fluoroscopy, navigation based on preoperative computed tomography, cone-beam CT-based navigation, O-arm, and intraoperative tomography provide improved surgical guidance. Navigation systems provide improved accuracy of more than 90% in the placement of pedicle screws. Tubular retraction systems coupled to pedicle screws allow their percutaneous insertion by minimally invasive spine surgery (MISS) techniques. They improve surgical access, allowing the insertion of intervertebral cages securely. Retraction systems offer stable retraction during surgery. The current systems are radiolucent, do not damage the tissue, and allow a L. E. Nuñez Alvarado (*) Pediatric Orthopedic Surgery, National Institute of Child Health – San Borja, Lima, Peru Department of orthopedics and traumatology, Clinica Anglo Americana, Lima, Peru © Springer Nature Singapore Pte Ltd. 2023 A. Banerjee et al. (eds.), Handbook of Orthopaedic Trauma Implantology, https://doi.org/10.1007/978-981-19-7540-0_101

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minimally invasive approach for the anterior, lateral, and posterior parts of the spine. Intraoperative neurophysiological monitoring (e.g., transcranial motorevoked potential and evoked electromyography) shows high sensitivity in detecting damage to the motor nerves and is very useful in spinal deformity surgery and in MISS. Laminar flow and high-efficiency particulate air (HEPA) filters have reduced microorganisms in the operating room. Modern surgical tables are versatile and radiolucent and allow the patient to be positioned, reducing the risk of pressure injuries. In addition, the use of microscope, endoscope, and thoracoscope in spinal surgery has improved the precision of surgery. Zoom and digital image enhancement have been crucial for minimally invasive surgery, achieving almost ambulatory spinal surgery. Thus, allied devices have improved the accuracy of implant placement and promoted the development of minimally invasive surgery, in turn allowing the evolution of modern implantology. Keywords

Allied devices · Spinal surgery · Spinal retraction systems · Tubular retraction systems · Neurophysiological monitoring · Image-guided navigation systems

Introduction Spine surgery has developed in leaps and bounds over the last 30 years. In our repertoire, we have a plethora of new surgical approaches and modern implants. With the further development of allied devices, surgical outcomes have improved tremendously. In this chapter, we attempt to discuss the various allied devices that have influenced the performance of spinal implant surgery.

Image Guidance and Navigation Systems in Spine Surgery X-rays, computed tomography (CT), and magnetic resonance imaging assist us with an understanding of pathology and are useful for surgical planning. However, they do not help us during the surgical procedure.

C-Arm The C-arm obtains images in real time (Fig. 1). It is a low-cost procedure that is widely available. Its disadvantages are radiation exposure and difficulty in obtaining axial and multiplanar images simultaneously, apart from the difficulty in arm positioning during operations which increases the surgical time and infection risk [1]. Gelalis et al. [2], in 2012, carried out a systematic review, where seven studies assessed 1902 inserted pedicle screw insertions with fluoroscopic assistance (FA). He found that between 28% and 85% were contained within the pedicle. Another

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Fig. 1 Mobile C-arm in spine surgery (BV Endura – DS, Mobile C-arm, Philips Medical Systems)

meta-analysis in 2019 [3] analysed 27 articles that used FA for 16,272 pedicle screw insertions and found the median precision to be 90.7% (30.1–99.7%). Access to intraoperative biplanar images of the C-arm allowed the development of minimally invasive spine surgery (MISS). Percutaneous screws have a placement accuracy of 71.7–98% [4–6]. Chung et al. [7] evaluated the FA of 127 cage placements during oblique lateral interbody fusion (OLIF) and observed a moderate obliquity variation from 25.2% intraoperatively to 49.6% in postoperative evaluation ( p 3 mm