DROR PALEY PRINCIPLES OF DEFORMITY CORRECTION

Transcription

1 DROR PALEY PRINCIPLES OF DEFORMITY CORRECTION

2 Springer-Verlag Berlin Heidelberg GmbH

3 DROR PALEY PRINCIPLES OF 0 E FOR M I TV CORRECTION With Editorial Assistance from J. E. Herzenberg With More Than 1,800 Separate Illustrations, Clinical Photographs, and Radiographs i Springer

4 DROR PALEY,MD,FRCSC Director, Rubin Institute for Advanced Orthopedics Sinai Hospital Co-Director, The International Center for Limb Lengthening, Sinai Hospital Baltimore, MD Present address: Rubin Institute for Advanced Orthopedics Sinai Hospital 2401 West Belvedere Avenue Baltimore, Maryland , USA ISBN ISBN (ebook) DOI / st ed Corr. 3rd printing 2005 CIP-data applied for Die Deutsche Bibliothek- CIP-Einheitsaufnahme Paley, Dror: Principles of deformity correction 1 Dror Paley. Berlin; Heidelberg; New York; Barcelona; Hongkong; London ; Mailand ; Paris ; Singapur ; Tokio : Springer, 2002 This work is subject to copyright. Ali rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. / Springer-Verlag Berlin Heidelberg 2002 Originally published by Springer-Verlag Berlin Heidelberg New York in 2002 Softcover reprint of the hardcover 1 st edition 2002 The use of general descriptive names, registered names, trademarks, 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. Product liability: The publishers cannot guarantee the accuracy of any information about dosage and application contained in this book. In every individual case the user must check such information by consulting the relevant literature. Cover design: E. Kirchner, Heidelberg Product management and layout: B. Wieland, Heidelberg Typesetting and production: AM-production, Wiesloch 24/ o Printed on acid-free paper

5 ~ This book is dedicated to the memory of my father, Zvi Paley, who gave so much and asked for so little.

6 Foreword - What is genius? Analyzing complex problems and finding simple ways to explain them in an understandable manner. By this definition, this book is genius. The most dramatic progress in orthopaedic surgery during the last 2 decades has been in the field of deformity correction. The treatment of deformities has occupied and challenged orthopaedic surgeons since Nicholas Andry. So many brilliant people have worked in this field. Among them, Friedrich Pauwel and Gavril Ilizarov should be individually named. Dr. Ilizarov developed new methods oflimb lengthening and deformity correction and sparked the newfound interest and developments in this field today. In Dror Paley, this spark became a raging fire. Dr. Paley inaugurated many innovations in the field of deformity correction. Among them, his nomenclature deserves special mention. Before his classification based on joint orientation, we had a plethora of confusing terminology and definitions leading to a confusion of language reminiscent of the Tower of Babel. Dr. Paley's nomenclature standardizes the terminology in a manner that requires little memorization. This logically based system has gained international recognition and acceptance as the single language of deformity analysis and correction. This book presents us with these concepts. The principles and concepts outlined in this book were not discovered or understood overnight. They represent an evolution of Dr. Paley's ideas from the past 14 years of clinical work in the field of deformity correction. Unlike other texts, which come and go because they are technique-centric, this tome is principle-based and will therefore stand the test of time. The limb lengthening and deformity reconstruction center created by Drs. Paley and Herzenberg in Baltimore is not only the clinical laboratory where this deformity correction work was developed and understood but has also become the Mecca for students in this medical specialty, with visitors from allover the world traveling to learn firsthand from these masters of deformity correction. It is in this manner that I first became exposed to the CORA method of mechanical and anatomic axis planning. This has resulted in a long-standing collaboration between our two facilities, centered on our common interest in this subspecialty. We routinely apply these principles to deformity correction at our center in Germany. Many of the new deformity correction devices that I and others are designing are now based on the CORA principles. Dr. Paley'S deformity correction courses around the world have popularized the planning methods and principles espoused in this book. The annual Baltimore Limb Deformity Course is the foundation for this book, workbook, and CD. Each of its chapters has been presented as lectures at this course, and the workbook and multimedia CD have been tested by live audiences at these courses for many years. I am sure this book will become the bible for the understanding, diagnosis, and treatment of lower limb deformities. Wiesbaden, Germany JOACHIM PFEIL

7 Preface - My prediction: this book will become a classic. Brave words, but I can safely make this statement because this book is not about the latest surgical operation or about our knowledge of certain pathologies, which is constant- 1y changing. Rather, this book presents a system of deformity analysis that is universal and applicable to any past, current, or future surgical osteotomy techniques and hardware. One needs only to think back to medical school and realize that most of the textbooks that we so carefully studied are now "of historic interest only:' Grant's Atlas of Anatomy is perhaps the only book from my medical school days that I still use. I predict that Paley's Principles of Deformity Correction will also have a long shelflife. The treatment of skeletal deformity is the heart of our specialty. Indeed, the very name of our specialty, orthopaedics, was coined by Nicholas Andry in 1741 as a word derived from two Greek words, orthos (meaning straight) and paedis (meaning child) to indicate his goal "to teach the different methods of preventing and correcting deformities of children" (from Mercer Rang's Anthology of Orthopaedics, 1966). Since Andry's writings 260 years ago, little progress has been made in understanding, analyzing, and quantifying the types of limb deformities. Rarely do we come across an orthopaedic surgeon who is truly an artist (or sculptor). Such an individual does not require accurate preoperative planning to execute a flawless corrective osteotomy. However, for the rest of us journeymen orthopaedic surgeons, achieving such beautiful artistic and aesthetic outcomes is elusive. We tend to take a wedge here or there, by eyeball estimation, and then rationalize the less than perfect appearance of the final X-ray. "It's not bad" or "it should remodel:' True, there have been attempts by notable surgeons, such as Friedrich Pauwels and Maurice Mueller, to be more precise in our planning. Although we may have received training in the precise repositioning of fracture fragments with plates and screws and accurate preoperative planning and templating for hip osteotomies, what has eluded us until now is a universally applicable lower extremity deformity planning system that takes into account the entire limb, including associated joint compensation and lever arm considerations: a unified or universal system that is equally applicable to the diverse range of ages and pathological abnormalities that come under the purview of the adult and pediatric orthopaedist. It has been my privilege and honor to be associated professionally with Dr. Dror Paley for the past 10 years, and I probably know him better than anyone else does. I have therefore been in a unique position to observe how he developed the CORA method and to contribute as a co-developer, editor, and author. Dr. Paley has an uncanny knack of clearly seeing and understanding orthopaedic deformities. More importantly, he has a unique ability to then process and integrate this information to make it accessible to the less clairvoyant. We have striven to make this method practical and teachable. It is not hard to learn, but it does take some effort and practice. The method is mercifully low-tech: the only tools required are a pencil, ruler, and goniometer. We have honed our ability to teach this method during the past 10 years at our annual Baltimore Limb Deformity Course, and many of the figures and cases illustrated in this book have been used in the course. The case studies and the artists' diagrams are all derived from our own practices and are representative of deformities that we have treated. In this regard, we are greatly indebted to our patients for providing us with both typical and atypical problems to study and illustrate. Interestingly, the CORA method of deformity analysis began simply as an attempt to make some sense of the Ilizarov apparatus. As the orthopaedic surgeon who introduced this method in Canada and the USA, Dr. Paley struggled to understand the concept of the Ilizarov hinge, which is what made the Ilizarov fixator so unique in its ability to correct deformities in a controlled fashion. In his early experience, he observed some of the secondary deformities that arose from mismatching the location of the hinge and the CORA. In his effort to more accurately identify the level for the Ilizarov hinge, he derived the CORA method of mechanical and anatomic axis planning described in this text. He quickly realized that the concept of the CORA and the osteotomy rules were not unique to the Ilizarov device but much more universally applicable to deformity correction by any method. Indeed, with the CORA method, one can understand and plan surgery for any lower extremity deformity from the hip to the foot. The gener-

8 al principle of this book is to first analyze, understand, and quantify the deformity. Only then should you begin to plan your surgical method and approach. Regardless of which type and brand of fixation is selected (plates, rods, or external fixator), the basic principles of deformity analysis and planning are the same. Failure to observe these principles frequently results in less than perfect alignment and often in secondary deformities that may be more difficult to correct than the original deformities. Ultimately, the surgeon must decide which device works best in his or her hands. The first step of preoperative planning, however, is universally required and beneficial. Chap. 11 includes a discussion of some of the vagaries of selected hardware devices, and it is this chapter that will most likely require updating and revision in a future edition as new device innovations become available. The bulk of the book, however, encompasses principles and concepts that will not change because they are based on simple geometry. Will the CORA method be supplanted by future technology? We think not. Even computer-dependent mathematical modeling of six-axis deformity correction (see Chap. 12) is first dependent on the surgeon to accurately understand, analyze, and quantify the radiographic deformity. We therefore think that the CORA method complements rather than competes with such sophisticated deformity correction methods. Is this book the final word on the topic? Clearly not. The CORA method is still a work in progress, and there is room to extend its application to the upper extremity, spine, pelvis, and perhaps even maxillofacial deformity correction. It has recently been incorporated into computer planning software. This book has already been lo years in the making, and these other expansions will have to wait for the second edition. We welcome readers' comments, criticisms, and feedback to help us improve future editions. Baltimore, Maryland JOHN E. HERZENBERG

9 The Story Behind This Book and the CORA Method - My first exposure to orthopaedics was as a medical student learning physical examination. My patient had a severe limp, which I attributed to weakness of his gluteus medius. What today I would recognize as an obvious Trendelenburg's gait, in 1977 was the pivotal event that sparked my interest in orthopaedic surgery. I began to read the works of Rene Caillet (The Biomechanics of Joints) and of LA. Kapandji (Physiology of Joints). Their books made human mechanics easy to comprehend, even for a medical student. With Principles of Deformity Correction, I attempt to do the same regarding deformity analysis and treatment. I am grateful to the many great teachers from my orthopaedic residency at the University of Toronto. They laid the foundation for my interest in orthopaedics. Professor Robert Salter set the tone, teaching in a Socratic manner. Dr. Alan Gross of Mt. Sinai Hospital first taught me the concept of the mechanical axis of the lower limb as well as the importance of preoperative planning for osteotomies of the hip and knee. He frequently quoted Renato Bombelli's Osteoarthritis of the Hip: Classification and Pathogenesis - The Role of Osteotomy as a Consequent Therapy (Springer-Verlag, 1983) and Paul Maquet's Biomechanics of the Knee: With Application to the Pathogenesis and the Surgical Treatment of Osteoarthritis (Springer-Verlag, 1984), which stimulated me to read these books on the biomechanics of the hip and knee, respectively. Drs. David MacIntosh and Ian Harrington taught me controversial concepts of high tibial osteotomies and alignment. Dr. Harrington's book on biomechanics (Biomechanics of Musculoskeletal Injury; Williams & Wilkins, 1982) and his often misunderstood article on high tibial osteotomy UBJS 65(2): , 1983] greatly influenced my understanding of concepts in this field. Drs. Marvin Tile, Joseph Schatzker, Robert McMurtry, and James Kellam are responsible for teaching me to think in terms of universal principles rather than specific surgical techniques. Principles to orthopaedics are like laws to physics: they remain constant, whereas specific operations and techniques come and go. The widest spectrum and complexity of deformity occur in pediatric orthopaedics in that many conditions affect the growth and development of the skeleton. My teachers at the Hospital for Sick Children, Drs. Norris Carroll, Colin Moseley, Mercer Rang, Walter Bobechko, Robert Gillespie, and Robert Salter, provided my initial exposure and understanding of the growth plate and the pediatric skeleton. The training I received from them during my residency and fellowship prepared me to challenge many well-established practices and beliefs in pediatric orthopaedics. Of all these, I received the greatest support from Dr. Norris Caroll, who always had faith in me and invested his time and patience to teach me meticulous surgical technique and who encouraged me at times of despair. I acknowledge the support of two of pediatric orthopaedics' elder statesmen, Drs. Lynn Staheli and Mihran Tachdjian. Dr. Staheli, as editor of the Journal of Pediatric Orthopedics, invited me to write about current techniques of limb lengthening in 1988 UPO 8:73-92, 1988) and more recently to write an editorial on deformity correction in the twenty-first century UPO 20: , 2000). Both of these publications helped introduce and heighten awareness to deformity correction principles. The late Dr. Tachdjian involved me in his internationally renowned pediatric orthopaedic review course since 1988 and included my deformity planning method in his textbooks (Pediatric Orthopedics, 1990; and Atlas of Pediatric Orthopedic Surgery, 1994). Dr. Charles Price, who took over this pediatric course, has included deformity planning by the CORA method as an important theme of the new course. In November 1983, when I was a third-year orthopaedic resident in Toronto, I met Renato Bombelli who was a visiting professor. Dr. Bombelli was a disciple of Friedrich Pauwels and a contemporary of Maquet, another of Dr. Pauwels' disciples. Through their writings, I began to understand that complicated joint mechanics could be reduced to simple principles. While in Toronto, Dr. Bombelli briefly mentioned the Ilizarov method. This offhand comment sparked my interest in a field totally unknown in North America. Upon completing my residency in 1985, I visited Dr. Maurizio Catagni in Italy to learn more about the Ilizarov method. The next year, I took my family to Europe and spent 6 months in Italy and the USSR studying limb reconstruction with exter-

10 nal fixation. I learned that deformities could occur in multiple planes and that hinges could act as the axis of correction. I learned to consider not only angulation but also translation, rotation, and length when analyzing a deformity. I also learned that deformities could be corrected gradually or acutely and that there were virtually no limits to how much angulation could be corrected. I visited Kurgan three times during the Soviet era, and I am greatly indebted to Professor Gavril Abramovich Ilizarov for the opportunity to study at his institute. Although I learned a great deal from Dr. Ilizarov's lectures, articles, and books, he was personally at his best when examining patients. Physical examination was a skill emphasized in my training in Toronto during the annual physical examination courses by Mr. Alan Graham Aply. Learning Russian facilitated the learning process and allowed me to speak to the Soviet doctors directly without going through interpreters. Many people in Kurgan contributed to my education, and some deserve special mention. Igor Kataev taught me the principle of hinges and of oblique plane deformity. Mr. Kataev was not a physician but was in charge of the patent office at Ilizarov's institute. Vladimir Shevtsov, Ilizarov's successor, answered the questions that I would not dare ask Ilizarov. He was direct and not evasive. Victor Makushin's ability to clinically evaluate nonunions was uncanny but could be divined only by reversing the Socratic method I learned from Dr. Tile and the others in Toronto. Arnold Popkov is a master at limb lengthening. He took the middle-of-the-road approach, allowing me to learn by answering my own questions and acknowledging when I hit upon the correct answers. Others helped in a clandestine fashion to overcome the cold war Soviet secrecy of the institute. The best example is Dr. Yaakov Odesky, who is now in Israel. He allowed me to see treatments and concepts that no Westerners had seen before. Finally, Galena Dyachkova's openness helped me to understand the basic science of the field of distraction, especially regarding soft tissues. In contrast to the struggle to learn in the USSR, Italy presented a refreshing sense of openness. The team, comprised of Roberto Cattaneo, Maurizio Catagni, and Angelo Villa in Lecco, Fabio Argnani in Bergamo, and Antonio Bianchi-Maiocchi in Milan, welcomed me with sincerity, kindness, and warmth and did everything to help me learn. I will forever be indebted to them. Of these outstanding teachers, Dr. Catagni is most responsible for my current understanding of deformities. He possesses an intuitive understanding of deformities and essentially computes a CORA analysis in his head as well as I can on paper. My goal with this book was to codify Dr. Catagni's intuitive approach into the objective CORA method that can be performed in a step-by-step fashion by all. One more important event occurred before all the pieces were in place. When I returned home from Italy and the USSR and began my pediatric orthopaedic fellowship in Toronto in 1987, I came across an article by Dr. Ken Krackow (Adv Orthop Surg 7:69,1983). This article introduced me to the concept of joint orientation angles and was pivotal in my developing the malalignment test. With this foundation upon which to build, the CORA method was developed. Placing hinges on the Ilizarov device involved putting the hinge just below the ring for metaphyseal deformities and at the apex of diaphyseal deformities. It did not make sense that the hinge should always be the same distance from the ring for all metaphyseal deformities. For diaphyseal deformities, we always drew two mid-diaphyseal lines and placed the hinge at the intersection of the two lines. In the metaphysis, it was not possible to draw a mid-diaphyseal line for the metaphyseal bone segment. I struggled with this problem until March 1988, when I had to place hinges for a supramalleolar osteotomy for ankle varus where the joint line was clearly tilted around the lateral cortex of the joint yet the osteotomy was much more proximal. Instead of placing the hinges just proximal to the distal tibial ring, I placed the hinge distal to the ring in what is now recognized as a juxta-articular hinge construct (see Chap. 11). To my fascination, the osteotomy site corrected with angulation and translation. The osteotomy rules were born together with the CORA method. The basic concepts in this book were developed over the next 2 years, based to the greatest extent on the clinical cases I had the privilege and the challenge to treat but also on a potpourri of ideas stimulated by colleagues with similar interests. Most notably, Stuart Green from California was my sounding board, especially when it came to posttraumatic deformities. Together, we solved the mystery of the relationship between the planes of angulation and translation. I was privileged to have Dr. Kevin Tetsworth, who has a brilliant mathematical mind, work with me as a fellow between 1989 and In 1990, we published the malalignment test and the first version of the CORA method, although it was not yet called that (Clin Orthop 280:48-64; 65-71). Dr. Natsuo Yasui from Osaka, Japan, coined the term CORA method, and it stuck. The initial concept of writing a book about deformity correction originated in 1991 through discussions with Darlene Cooke, who was then a book editor at Williams & Wilkins. The syllabus for the first annual Baltimore Limb Deformity Course served as an outline for the book. This course began in 1989, with Ilizarov as a featured guest speaker, and has continued ever since. The success of this annual course led me to add more material and to incorporate the concepts of some very innovative contributors who participated in our course. Ms. Cooke thought that I would never finish the book because I was a perfectionist and continued to add new material every year. In many respects, she was right. On the other hand, the book was not ready to be finished. There were several concepts that were on the verge of

11 being clarified and that needed to be included in the book to make it complete. For example, the six-axis deformity correction concepts introduced by Dr. J. Charles Taylor and the lever arm deformity concepts presented by Dr. James Gage. In 1998, Williams & Wilkins and I agreed to drop the book project. Without Ms. Cooke as my editor, the external push to complete the book was gone. I saw 10 years of work to produce this book going to waste. I decided upon a new strategy: finish the book on our own, and then look for a publisher. With the help of our in-house publishing team, Senior Editor Dori Kelly, Medical Illustrator Joy Marlowe, and Multimedia Specialist Mark Chrisman, this became a reality. It was now time to seek a new publisher. This was easier said than done. I could not get an American publishing company to share my vision of the importance of this book. The project was finally salvaged by Dr. Joachim Pfeil, my friend and colleague from Wiesbaden, Germany. Dr. Pfeil has promoted the CORA method in Europe for years and has co-authored an article on this subject in the German language. He introduced me to Gabriele Schroeder, Senior Medical Editor for Springer-Verlag in Heidelberg in April This book has finally come to fruition with the enthusiastic support of Springer-Verlag. This history and my acknowledgments would not be complete without mentioning a few more people. First is Dr. John E. Herzenberg, without whose editorial assistance this book would not have been possible. Dr. Herzenberg has been my colleague and friend since we were fellows together in Toronto in 1985 and We continued to correspond and collaborate at a distance until 1991, when Dr. Herzenberg moved to Maryland to help achieve our common dream of developing a limb lengthening and deformity correction center. The Maryland Center for Limb Lengthening & Reconstruction (MCLLR) was born. John has been a valuable sounding board for my ideas for more than 10 years. He encouraged me to continually strive to simplify my concepts to make them teachable and practical. He has been my Co Chairman in the Deformity Course and my loyal partner in practice. It is often impossible to separate who originated which ideas. Therefore, this book is as much a testament to his work as it is to mine. Second is Anil Bhave, PT. Mr. Bhave has directed our gait laboratory and served as clinical research coordinator since He has contributed immeasurably to my understanding of gait and dynamic deformities. The rest of the loyal staff of the MCLLR have also contributed to this book in one way or another. Kernan Hospital and the Department of Orthopaedics have given me tremendous support and a wonderful environment for my work during the past 14 years. lowe them all a great debt of gratitude. Finally, I would like to acknowledge my family. My wife, Wendy Schelew, and our children, Benjamin, Jonathan, and Aviva, have stood beside me all these years and tolerated my single-minded devotion to completing this project. This book is a testimony to their patience, love, and support. It is also a testimony to my parents. From my mother, a school teacher, I inherited ambition, love for the life sciences, and my skill of teaching. My greatest sadness is that my father, who was my role model, will never see this book. He was a holocaust survivor who at age 38 (when I was 10) completed his PhD. He was a mechanical engineer who specialized in metallurgy, working as a research scientist in Ottawa, Canada, until his untimely death from cancer at age 54. My father was a Renaissance man who spoke nine languages and who stimulated my interest in many fields. Most of all, he taught me to think critically. He grew up approximately 100 miles from Kurgan in the Soviet Union. He never got to see me complete my residency, raise a family, learn Russian, or achieve the publication of this book. It is to his memory that I dedicate this book. Baltimore, Maryland DROR PALEY

12 Contributing Authors I am indebted to the chapter contributors, without whose input this book would be deficient. These select authors were invited because of their original ideas and contributions to the field of deformity correction. The numbers and titles of the chapters to which they contributed are listed below their names. For the consistency of this book, I have edited and added to each of these chapters to better incorporate these authors' ideas. I especially thank my partner, John E. Herzenberg, who in addition to contributing as an author to two chapters in the book helped me to develop and also originated many of the deformity concepts presented herein. John acted as this book's content editor for both the text and the figures. This laborious task has refined and clarified the theoretical and practical principles that this book presents. DROR PALEY, MD, FRCSC ANIL BHAVE,PT Director of Rehabilitation and Gait Laboratory The International Center for Limb Lengthening, Sinai Hospital Baltimore, MD CHAPTER 21: Gait Considerations JIM GAGE,MD Medical Director, Gillette Children's Hospital St. Paul,MN Professor of Orthopaedics, University of Minnesota Minneapolis, MN CHAPTER 22: Dynamic Deformities and Lever Arm Considerations JOHN E. HERZENBERG, MD, FRCSC Co-Director, The International Center for Limb Lengthening, Sinai Hospital Chief of Pediatric Orthopedics, Sinai Hospital Baltimore, MD CHAPTER 9: Rotation and Angulation-Rotation Deformities CHAPTER 12: Six-Axis Deformity Analysis and Correction CHAPTER 20: Growth Plate Considerations MICHAEL MONT,MD Co-Director, Joint Preservation and Replacement Center, Sinai Hospital Baltimore, MD CHAPTER 23: Total Knee Replacement and Total Hip Replacement Associated with Malalignment MICHAEL SCHWARTZ, PHD Director of Bioengineering Research Gillette Children's Hospital, St. Paul, MN Assistant Professor of Orthopaedics University of Minnesota Minneapolis, MN CHAPTER 22: Dynamic Deformities and Lever Arm Considerations SHAWN C. STANDARD, MD Pediatric Orthopedic Surgeon The International Center for Limb Lengthening, Sinai Hospital Baltimore, MD CHAPTER 12: Six-Axis Deformity Analysis and Correction J. CHARLES TAYLOR,MD Orthopedic Surgeon, Specialty Orthopedics Memphis, TN CHAPTER 12: Six-Axis Deformity Analysis and Correction KEVIN TETSWORTH,MD Director of Orthopaedics, Royal Brisbane Hospital Brisbane, Queensland, Australia CHAPTER 13: Consequences of Malalignment

13 Senior Editor DORI KELLY,MA Medical Illustrators JOY MARLOWE, MA MARY GOLDSBOROUGH,MA STACY LUND, MA Multimedia Specialist MARK CHRISMAN,Bs

14 Contributing Authors _ Drs. Dror Paley, MD, FReSe, and John E. Herzenberg, MD, FRese DR 0 R PAL E Y was born in Tel Aviv, Israel, in 1956 and moved to North America in He grew up in Ottawa, Canada, for most of his youth. He graduated from the University of Toronto Medical School in 1979, completed his internship in surgery at the Johns Hopkins Hospital in Baltimore in 1980, and completed his orthopaedic surgery residency at the University of Toronto Hospitals in After completing a hand and trauma surgery fellowship at Sunnybrook Hospital in Toronto and the AOA-COA North American Traveling Fellowship, he spent 6 months studying limb lengthening and reconstruction techniques in Italy and the USSR and then completed a pediatric orthopaedics fellowship at the Hospital for Sick Children in Toronto. This is where he began his limb lengthening and deformity correction experience. In November 1987, he organized the first international meeting on the Ilizarov techniques with Dr. Victor Frankel, at which Professor Gavril Abramovich Ilizarov shared his knowledge in the United States for the first time. The same month, Dr. Paley joined the orthopaedic faculty of the University of Maryland. Many of the original concepts for this book were developed during the next 3 years. In 1991, Drs. John E. Herzenberg and Kevin Tetsworth joined Dr. Paley to form the Mary- land Center for Limb Lengthening & Reconstruction in Baltimore. In 1989, Dr. Paley organized and inaugurated ASAMI North America, the limb lengthening and reconstruction society, and served as the first president of this new subspecialty society. The first AS AMI meeting also coincided with the first Baltimore Limb Deformity Course. The publication of this book will debut at the 11th Annual Baltimore Limb Deformity Course and will be the manual of this internationally recognized course. Dr. Paley has been active in teaching limb reconstruction worldwide (more than 50 countries to date). He lectures and reads in six languages (English, Hebrew, French, Italian, Spanish, and Russian). In 1990, Dr. Paley was awarded a Gubernatorial Citation for Outstanding Contributions in Orthopaedic Surgery by the Governor of Maryland. He was also awarded the Pauwels Medal in Clinical Biomechanics by the German-Speaking Countries Orthopaedic Association in His most cherished award, however, is the Orthopaedic Residents Teaching Award, which he has received on more than one occasion. Dr. Paley was the Chief of Pediatric Orthopaedics at the University of Maryland until June 2001 and was Professor of Orthopaedic Sur-

15 gery at the University of Maryland Medical System until October He is well published in the peer-reviewed literature and has also authored and edited several books and numerous book chapters. He considers Principles of Deformity Correction to be his thesis and his most important academic achievement. On July 1,2001, Dr. Paley, together with Drs. John Herzenberg, Michael Mont, and Janet Conway, opened the Rubin Institute for Advanced Orthopedics at Sinai Hospital, in Baltimore. Dr. Paley is the Director of this new orthopaedic center and Co-Director of The International Center for Limb Lengthening. Dr. Paley is married to Wendy Schelew, and they have three children (Benjamin, Jonathan, and Aviva). For fun, he enjoys personal fitness, skiing, scuba diving, biking, and studying history. JOHN E. HERZENBERG was born in 1955 in Springfield, Massachusetts. At the age of 15, he left to attend high school at Kibbutz Kfar Blum in Israel. He studied medicine at Boston University and completed his internship in surgery at Albert Einstein-Montefiore Hospitals in New York. In 1985, he completed his residency in orthopaedic surgery at Duke University in Durham, NC, where he was drawn toward pediatric orthopaedics by his mentor and chief, Dr. J. Leonard Goldner. Dr. Herzenberg completed a pediatric orthopaedic fellowship at the Hospital for Sick Children in Toronto, where he first met Dr. Dror Paley. He was on the faculty at the University of Michigan in Ann Arbor for 5 years, with Dr. Robert Hensinger. Dr. Herzenberg traveled to Italy' USSR, and Baltimore to study limb reconstruction techniques. This began his active collaboration with Dr. Paley, which resulted in a joint vision to set up a national center devoted to limb reconstructive surgery. In 1991, Dr. Herzenberg joined Drs. Paley and Tetsworth on the full-time faculty of the University of Maryland in Baltimore to establish the Maryland Center for Limb Lengthening & Reconstruction. Dr. Herzenberg has traveled extensively, teaching the Ilizarov techniques and the CORA method of deformity planning. He has served as president of ASAMI-North America and is active as a volunteer surgeon with Operation Rainbow and Operation Smile, participating in yearly missions to Central and South Americas. He was awarded both the AOA-COA North American and ABC Traveling Fellowships. He is extensively published in many areas of pediatric orthopaedics and limb reconstruction. Dr. Herzenberg was Professor of Orthopaedic Surgery at the University of Maryland Medical System until October 2003 and is currently Co-Director of the International Center for Limb Lengthening and Chief of Pediatric Orthopedics at Sinai Hospital. Dr. Herzenberg is married to Merrill Chaus, and they have three daughters (Alexandra, Danielle, and Brittany). For fun, he enjoys personal fitness and Bible study.

16 Contents 1 Normal lower limb Alignment and Joint Orientation... 1 Mechanical and Anatomic Bone Axes... Joint Center Points... Joint Orientation lines Ankle Knee Hip Joint Orientation Angles and Nomenclature Mechanical Axis and Mechanical Axis Deviation (MAD). 10 Hip Joint Orientation. 12 Knee Joint Orientation Ankle Joint Orientation References Malalignment and Malorientation in the Frontal Plane Frontal Plane Mechanical and Anatomic Axis Planning Mechanical Axis Planning Anatomic Axis Planning Determining the CORA by Frontal Plane Mechanical and Anatomic Axis Planning: Step by Step. 64 Part I: CORA Method, Tibial Deformities Mechanical Axis Planning oftibial Deformities.. 64 Anatomic Axis Planning of Tibial Deformities.. 74 Part II: CORA Method, Femoral Deformities. 76 Mechanical Axis Planning of Femoral Deformities 76 Anatomic Axis Planning of Femoral Deformities Multiapical Deformities Malalignment MAT Malorientation of the Ankle and Hip.. 28 Orientation of the Ankle and Hip in the Frontal Plane. 28 MOT of the Ankle MOT of the Hip.. 30 References Radiographic Assessment oflower Limb Deformities Knee Ankle and Hip Radiographic Examination in the Sagittal Plane Knee Ankle Hip Radiographic Examination in One Plane When There Is a Deformity Component in the Other Plane Osteotomy Concepts and Frontal Plane Realignment Angulation Correction Axis (ACA) Bisector Lines Relationship of Osteotomy Type to Bisector Lines. 101 Osteotomy Rules Translation and length Displacement atthe Osteotomy Line Opening Wedge Osteotomy Closing Wedge Osteotomy Focal Dome Osteotomy Clinical Choice of Osteotomy Level and Type 114 Multiapical Osteotomy Solutions Single Osteotomy Solutions Multiple Osteotomy Solutions. 142 References Sagittal Plane Deformities References Sagittal Plane Alignment in the lower Limb. 155 Sagittal Plane MAT Knee Joint Malorientation

17 .. Contents Overall Sagittal Plane MOT.... Knee Level Sagittal Plane MOT.... Overall Sagittal Plane MOT of the Ankle. Ankle Level Sagittal Plane MOT of the Ankle Sagittal Plane Anatomic Axis Planning oftibial Deformity Correction... Sagittal Plane Anatomic Axis Planning of Femoral Deformity Correction.. Osteotomies in the Sagittal Plane. References Oblique Plane Deformities Plane of Angulation.. Graphic Method..... Graphic Method Error.. Base oftriangle Method Axis of Correction of Angulatory Deformities. Definition of Angulation.. References Rotation and Angulation-Rotation Deformities Clinical Assessment of Rotation Deformities Level of Osteotomy for Rotation Deformities Frontal Plane Preoperative Planning for Rotation Deformities Factoring in Rotation for Mechanical Axis Planning of the Femur Frontal Plane Anatomic Axis Planning for Rotation Deformities Combined Angulation and Rotation Deformities Locating the Inclined Axis Locating the Inclined Osteotomy Inclined Focal Dome Osteotomy Clinical Examples References Length Considerations: Gradual Versus Acute Correction of Deformities Translation and Angulation-Translation Deformities Translation Deformity Two Angulations Equal One Translation.. Translation Effects on MAD... Osteotomies for Correction oftranslation Deformity.. Combining Angulation and Translation.. a-t Deformities and MAD... Graphic Analysis of a-t Deformities.. Type 1: Angulation and Translation in the Same Plane Anatomic Plane Deformity.... Oblique Plane Deformity Type 2: Angulation and Translation in Different Planes Anatomic Plane Deformity with Angulation and Translation 90 Apart Oblique Plane Deformity with Angulation and Translation 90 Apart One Anatomic and One Oblique Plane Deformity with Angulation and Translation in Different Planes Less Than 90 Apart Oblique Plane Deformity with Angulation and Translation Less Than 90 Apart Osteotomy Correction of a-t Deformities Osteotomy Correction of Angulation and Translation in the Same Plane Correction of Angulation and Translation in Different Planes Multilevel Fracture Deformities References Length Considerations for Angular Corrections Neurovascular Structures Nerves Vessels Muscles, Tendons, and Fascia 287 Ligaments Skin References Ha rdware and Osteotomy Considerations Choice of Hardware.... Patient Age Osteotomy Types... Closing Wedge Osteotomy. Opening Wedge Osteotomy..... Angulation-Translation Osteotomy. Dome Osteotomy. Hardware.... Plate Fixation Intramedullary Nails.. External Fixation.. Order of Correction... Lever Arm Principle.. Method of Osteotomy References

18 Contents 12 Six-Axis Deformity Analysis and Correction , 6 Realign ment for Mono-com partment Osteoarthritis of the Knee The Taylor Spatial Frame Fixator.. Introduction Modes of Correction.. Planning Methods... Fracture Method.. CORAgin Method.. CORAsponding Point Method... Virtual Hinge Method Line of Closest Approach (LOCA). Taylor Computer-assisted Design (CAD) Software Reference Concepts Rate of Correction and Structure at Risk (SAR). 430 Parallactic Homologues of Deformity: Proximal versus Distal Reference Perspective References Consequences of Malalignment Static Considerations Dynamic Considerations Rotational Considerations. 443 Animal Laboratory Models.444 Cadaver Laboratory Models.444 Clinical Longitudinal Studies Summary. 448 References Malalignment Due to Ligamentous Laxity ofthe Knee... 4S 1 Deformities in Association with MCOA Bone Deformities Joint Deformities Customized HTO Malalignment Test form Mono-Compartment Osteoarthritis Femoral versus Tibial Osteotomy Level of Center of Rotation of Angulation Magnitude of Correction Type of Osteotomy and Fixation Considerations Medial Compartment Osteoarthritis Varus plus Medial Collateral Ligament Pseudo laxity Medial Compartment Osteoarthritis Varus plus Lateral Collateral Ligament Pseudo laxity Medial Compartment Osteoarthritis Varus plus Rotation Deformity Medial Compartment Osteoarthritis Varus plus Hyperextension Medial Compartment Osteoarthritis Varus plus Fixed Flexion Deformity Medial Compartment Osteoarthritis Varus plus Lateral Subluxation Medial Compartment Osteoarthritis Varus plus Medial Plateau Depression Lateral Compartment Osteoarthritis (LCOA). 504 References Sagittal Plane Knee Considerations LCL Laxity. MCL Laxity References 1 S Knee Joint Li ne Deformity Sources of Malalignment Frontal Plane Knee Considerations.. FFD ofthe Knee.... HE and Recurvatum Knee Deformity.. Knee Extension Contracture.... Patella Baja and Alta. References References Ankle and Foot Considerations Frontal Plane Ankle Deformities Supramalleolar Osteotomy for Varus and Valgus Deformities Sagittal Plane Ankle Deformities Supramalleolar Osteotomy for Recurvatum and Procurvatum Deformities Compensatory Mechanisms and Deformities: Mobile, Fixed, and Absent

19 DIll Contents Specific Ankle Malalignment Deformities Ankle Fusion Malunion Flattop Talus Deformity Ball and Socket Ankle Joint Overcorrected Clubfoot and Other Lateral Translation Deformities of the Heel... Posterior Tibial Tendon Dysfunction... Completely Stiff Foot Treatment by Supramalleolar Osteotomy... Partial Growth Arrest... Malunion of Fibula... Ankle Contractu res. References Hip Joint Considerations Limb in Neutral Alignment to Pelvis, No Intraor Periarticular Limitation of Range of Motion. 647 Varus Deformity Valgus Deformity Limb in Neutral Alignment to Pelvis, Intra-articular Limitation of Range of Motion Varus Deformity Valgus Deformity Lesser Trochanter Considerations Greater Trochanter Considerations Sagittal Plane Considerations Deformities of the Head and Neck of the Femur Pseudo-subluxation of the Hip Deformities Due to Hip Ankylosis and Arthrodesis between the Femur and the Pelvis Pelvic Support Osteotomy References Growth Plate Considerations LLD Predicting LLD Multiplier Method Additional Growth Databases Relationship of Multipliers for Boys to Multipliers for Girls Development of the Multiplier Limb Length Discrepancy Prediction Formulae Prediction of Limb Length Discrepancy at Skeletal Maturity Using the Multiplier Growth-Remaining Method for Cases of Postnatal Developmental Discrepancy Percentage of Total Bone Growth from the Distal Femur and Proximal Tibia Using the Multiplier Method to Calculate Timing for Epiphysiodesis Growth Prediction Controversies Growth Plate Considerations Relative to Deformity Cause of Deformities Developmental Angular Deformities Angular Deformities: Gradual Correction by Hemi-epiphysiodesis Planning for Hemi-epiphyseal Stapling for Angular Correction at the Knee in Children. 708 Multiplier Method for Timing Hemi-epiphyseal Stapling for Correction of Angular Deformity Multiplier Method for Calculating When to Remove Hemi-epiphyseal Staples in Young Children References Gait Considerations Gait Considerations in Association with Lower Limb Deformities. Sacrifice ofjoint Motion... Fixed Joint Position Abnormal Loading ofjoints... Compensatory Mechanisms.... Frontal Plane Malalignment.... Distal Tibia Varus or Valgus Varus Deformity at the Knee. Valgus Deformity of the Knee Varus or Valgus Deformity of the Proximal Femur..... Sagittal Plane Deformity Ankle Equinus Deformity... Excessive Ankle Dorsiflexion or Calcaneus Deformity... Ankle Arthrodesis Deformities. Anterior Translation of the Foot. Fixed Flexion Deformity of the Knee.. Recurvatum of the Knee Hip Flexion Deformity.... Hip Fusion Rotational Malalignment Leg Length Considerations References Dynamic Deformities and Lever Arm Considerations Levers.... Mechanical Advantage. Moments and Motions. Redundancy.... Normal Function Introduction Mechanics of the Ankle: First Rocker

20 Contents _ Mechanics of the Ankle: Second Rocker Mechanics of the Ankle: Third Rocker Force Production and Compensation Pathological Function. 768 Short Lever Arm Flexible Lever Arm Malrotated Lever Arm Unstable Fulcrum Positional Abnormalities 773 References TKR and Total Hip Replacement Associated with Malalignment Normal Alignment Versus Malalignment in Association with Total Knee Arthroplasty. Management of Fixed Soft Tissue Deformities. Clinical Assessment.... Radiographic Assessment Intraoperative Placement of Components and Consequences of Malalignment.... Varus Deformities Valgus Deformities Flexion Deformity and Contracture Recurvatum Deformity Peroneal Nerve Palsy and Operative Release. Trial Reduction after Ligamentous Balancing. Summary of Soft Tissue Balancing Principles.. Extra-articular Bone Deformities..... Total Knee Arthroplasty after Failed HTO.... Preoperative Assessment Proximal Tibial Osteotomy-Related Problems fortkr.... Proximal Femoral Deformities and Total Hip Arthroplasty... Preoperative Planning Soft Tissue Balancing..... Bone Deformity Correction. References Subject Index

21 Glossary a anatomic LOCA line of closest approach A anterior LON lengthening over nail ACA angulation correction axis LPFA lateral proximal femoral angle ACL anterior cruciate ligament m mechanical AOTA anterior distal tibial angle M medial ajco anatomic axis to joint center distance MAD mechanical axis deviation ajcr anatomic axis: joint center ratio MAT malalignment test ajeo anatomic axis to joint edge distance MCL medial collateral ligament ajer anatomic axis:joint edge ratio MCOA medial compartment osteoarthritis alofa anatomic lateral distal femoral angle MOA mid-diaphyseal angle AMA anatomic-mechanical angle mlofa mechanical lateral distal femoral angle AP anteroposterior (for radiograph) MM medial malleolus appta anatomic posterior proximal tibial angle mmofa mechanical medial distal femoral angle ASIS anterior superior iliac spine MNSA medial neck shaft angle a-t angulation-translation MOT malorientation test CORA center of rotation of angulation MPFA medial proximal femoral angle 0 distal MPTA medial proximal tibial angle OAA distal anatomic axis NSA neck shaft angle OMA distal mechanical axis P posterior (when used in conjunction with F femur A for anterior, M for medial, and L for lateral) FAN fixator-assisted nailing P proximal FFO fixed flexion deformity PAA proximal anatomic axis GRV ground reaction vector POFA posterior distal femoral angle HE hyperextension PPFA posterior proximal femoral angle HTO high tibial osteotomy PMA proximal mechanical axis IMN intramedullary nail PPTA posterior proximal tibial angle JLCA joint line convergence angle SA surface area L lateral SAR structure at risk LAT lateral (for radiographic view only) SCFE slipped capital femoral epiphysis IBL longitudinal bisector line SO standard deviation LCL lateral collateral ligament T tibia LCOA lateral compartment osteoarthritis tbl transverse bisector line LOTA lateral distal tibial angle TKR total knee replacement LLO limb length discrepancy WBF weight-bearing force