Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5 [5 ed.] 2016947582, 9781625525505, 9781975123796

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Orthopaedic

Knowledge Update Hip and Knee Reconstruction The Hip Society The Knee Society Editors Michael A. Mont, MD Michael Tanzer, MD, FRCSC

Orthopaedic

Knowledge Update Hip and Knee Reconstruction Editors Michael A. Mont, MD Chairman Department of Orthopaedic Surgery Cleveland Clinic Foundation Cleveland, Ohio

Michael Tanzer, MD, FRCSC Jo Miller Chair and Professor of Surgery Division of Orthopaedic Surgery McGill University Montreal, Quebec, Canada

Developed by The Hip Society and The Knee Society

Board of Directors, 2016-2017 Gerald R. Williams Jr, MD President William J. Maloney, MD First Vice-President David A. Halsey, MD Second Vice-President M. Bradford Henley, MD, MBA Treasurer David D. Teuscher, MD Past-President Basil R. Besh, MD Lisa K. Cannada, MD Howard R. Epps, MD Daniel C. Farber, MD Brian J. Galinat, MD, MBA Daniel K. Guy, MD Lawrence S. Halperin, MD Amy L. Ladd, MD Brian G. Smith, MD Ken Sowards, MBA Karen L. Hackett, FACHE, CAE (ex officio)

Staff Ellen C. Moore, Chief Education Officer Hans Koelsch, PhD, Director, Department of Publications Lisa Claxton Moore, Senior Manager, Book Program Steven Kellert, Senior Editor Kathleen Anderson, Senior Editor Courtney Dunker, Editorial Production Manager Abram Fassler, Publishing Systems Manager Suzanne O’Reilly, Graphic Designer Susan Morritz Baim, Production Coordinator Karen Danca, Permissions Coordinator Charlie Baldwin, Digital and Print Production Specialist

The material presented in Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5 has been made available by the American Academy of Orthopaedic Surgeons for educational purposes only. This material is not intended to present the only, or necessarily best, methods or procedures for the medical situations discussed, but rather is intended to represent an approach, view, statement, or opinion of the author(s) or producer(s), which may be helpful to others who face similar situations. Some drugs or medical devices demonstrated in Academy courses or described in Academy print or electronic publications have not been cleared by the Food and Drug Administration (FDA) or have been cleared for specific uses only. The FDA has stated that it is the responsibility of the physician to determine the FDA clearance status of each drug or device he or she wishes to use in clinical practice. Furthermore, any statements about commercial products are solely the opinion(s) of the author(s) and do not represent an Academy endorsement or evaluation of these products. These statements may not be used in advertising or for any commercial purpose. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Published 2017 by the American Academy of Orthopaedic Surgeons 9400 West Higgins Road Rosemont, IL 60018 Copyright 2017 by the American Academy of Orthopaedic Surgeons Library of Congress Control Number: 2016947582 ISBN: 978-1-62552-550-5 Printed in the USA

Hollie Muir, Digital and Print Production Specialist Emily Douglas, Page Production Assistant Sylvia Orellana, Publications Assistant

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Acknowledgments Editorial Board Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

The Knee Society Executive Board, 2016

Michael A. Mont, MD Chairman Department of Orthopaedic Surgery Cleveland Clinic Foundation Cleveland, Ohio

Adolph V. Lombardi, Jr, MD, FACS 1st Vice President

Michael Tanzer, MD, FRCSC Jo Miller Chair and Professor of Surgery Division of Orthopaedic Surgery McGill University Montreal, Quebec, Canada

The Hip Society Executive Board, 2016 Harry E. Rubash, MD President Kevin L. Garvin, MD 1st Vice President  Douglas E. Padgett, MD 2nd Vice President Craig J. Della Valle, MD Secretary Joshua J. Jacobs, MD Treasurer Daniel J. Berry, MD Immediate Past President Kevin J. Bozic, MD, MBA Education Committee Chair Michael Tanzer, MD, FRCSC Membership Committee Chair Richard Iorio, MD Research Committee Chair Donald Garbuz, MD, MHSc, FRCSC Member-At-Large

Thomas P. Sculco, MD President

Robert L. Barrack, MD 2nd Vice President Mark W. Pagnano, MD 3rd Vice President Michael E. Berend, MD Secretary John J. Callaghan, MD Treasurer Thomas P. Vail, MD Immediate Past President Thomas K. Fehring, MD Past President Stephen J. Incavo, MD Education Committee Chair Keith R. Berend, MD Education Committee Chair Elect Mark P. Figgie, MD Membership Committee Chair Christopher L. Peters, MD Membership Committee Chair Elect Michael J. Dunbar, MD, FRCSC, PhD Research Committee Chair Craig J. Della Valle, MD Member-At-Large Richard Iorio, MD Member-At-Large Bassam A. Masri, MD, FRCSC Technology Committee Chair (Ex-Officio)

Adolph V. Lombardi, Jr, MD, FACS Fellowship & Mentorship Committee Chair (Ex-Officio)

© 2017 American Academy of Orthopaedic Surgeons

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Explore the full portfolio of AAOS educational programs and publications across the orthopaedic spectrum for every stage of an orthopaedic surgeon’s career, at www.aaos.org. The AAOS, in partnership with Jones & Bartlett Learning, also offers a comprehensive collection of educational and training resources for emergency medical providers, from first ­responders to critical care transport paramedics. Learn more at www.aaos.org/ems.

Contributors Mansour Abolghasemian, MD Assistant Professor Department of Orthopedic Surgery Shafa Hospital, Iran University of Medical Sciences Tehran, Iran Anthony Albers, MD, FRCSC Adult Hip and Knee Reconstruction Fellow Department of Orthopaedics University of British Columbia Vancouver, British Columbia, Canada Ram K. Alluri, MD Research Fellow Department of Orthopaedic Surgery Keck School of Medicine Los Angeles, California Hussain Al-Yousif, MD Fellow, Surgeon Department of Orthopaedic Surgery The Ottawa Hospital, King Saud Medical City Ottawa, Ontario, Canada Matthew S. Austin, MD Professor Department of Orthopaedic Surgery Sidney Kimmel Medical College Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania David C. Ayers, MD Professor, Arthur M. Pappas Chair Department of Orthopedics and Physical Rehabilitation University of Massachusetts Medical School Worchester, Massachusetts David Backstein, MD, MEd, FRCSC Head, Granovsky Gluskin Division of Orthopaedics Mount Sinai Hospital University of Toronto Toronto, Ontario, Canada

© 2017 American Academy of Orthopaedic Surgeons

John W. Barrington, MD Co-Director, Surgeon Joint Replacement Center at Baylor Medical Center of Frisco Plano Orthopedic Sports Medicine & Spine Center Plano, Texas Wael K. Barsoum, MD Vice Chairman Department of Orthopaedic Surgery Cleveland Clinic Cleveland, Ohio Paul E. Beaulé, MD, FRCSC Head, Division of Orthopaedics Department of Surgery, Division of Orthopaedic Surgery The Ottawa Hospital Ottawa, Ontario, Canada David M. Beck, MD Resident Department of Orthopaedic Surgery Thomas Jefferson University Hospital Philadelphia, Pennsylvania Keith R. Berend, MD President and CEO White Fence Surgical Suites Senior Partner Joint Implant Surgeons New Albany, Ohio Daniel J. Berry, MD L.Z. Gund Professor of Orthopedic Surgery Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota Mathias P.G. Bostrom, MD Professor of Orthopaedic Surgery Senior Research Scientist Chief of Hip Service Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York

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Charles R. Bragdon, PhD Research Scientist Department of Orthopedics Massachusetts General Hospital Boston, Massachusetts

John C. Clohisy, MD Professor Department of Orthopaedic Surgery Washington University School of Medicine St. Louis, Missouri

Justin G. Brothers, MD Fellow Department of Orthopaedics University of Utah Salt Lake City, Utah

Benjamin R. Coobs, MD Assistant Professor Department of Orthopaedic Surgery Virginia Tech Carilion School of Medicine and Research Institute Roanoke, Virginia

J.W. Thomas Byrd, MD President and Orthopaedic Surgeon Nashville Sports Medicine Foundation Nashville, Tennessee John J. Callaghan, MD Lawrence and Marilyn Dorr Chair and Professor Department of Orthopaedics and Rehabilitation University of Iowa Iowa City, Iowa Alberto Carli, MD, MSc, FRCSC Orthopaedic Surgeon Division of Orthopaedic Surgery The Ottawa Hospital Ottawa, Ontario, Canada Sasha Carsen, MD, MBA, FRCSC Assistant Professor of Surgery Department of Surgery Children’s Hospital of Eastern Ontario, The Ottawa Hospital University of Ottawa Ottawa, Ontario, Canada Morad Chughtai, MD Research Fellow Department of Orthopaedics Rubin Institute for Advanced Orthopaedics Baltimore, Maryland Henry D. Clarke, MD Professor of Orthopedics Department of Orthopedic Surgery Mayo Clinic Phoenix, Arizona

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Fred D. Cushner, MD Chief Division of Orthopaedic Surgery at South Side Hospital Northwell Health New York, New York Sachin Daivajna, MS, FRCS (Orth) Fellow Department of Adult Reconstructive Surgery Division of Reconstructive Orthopaedics University of British Columbia Vancouver, British Columbia, Canada Rocco D’Apolito MD Research Fellow Complex Joint Reconstruction Center Hospital for Special Surgery New York, New York Gregory K. Deirmengian, MD Associate Professor Department of Orthopaedic Surgery Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania Ronald E. Delanois, MD Fellowship Director Center for Joint Preservation and Replacement Rubin Institute for Advanced Orthopaedics, Sinai Hospital of Baltimore Baltimore, Maryland Craig J. Della Valle, MD Orthopaedic Surgeon Midwest Orthopaedics at Rush Rush University Medical Center Chicago, Illinois © 2017 American Academy of Orthopaedic Surgeons

Ivan De Martino, MD Fellow Complex Joint Reconstruction Center Hospital for Special Surgery New York, New York Douglas A. Dennis, MD Adjunct Professor Department of Bioengineering University of Denver Assistant Clinical Professor Department of Orthopaedics University of Colorado School of Medicine Denver, Colorado Nicholas M. Desy, MD, FRCSC Clinical Fellow in Adult Lower Extremity Reconstruction Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota Christopher A. Dodd, FRCS Consultant Orthopaedic Surgeon University of Oxford Oxford, England Michael J. Dunbar, MD, FRCSC, PhD Professor of Surgery Department of Surgery Dalhousie University Halifax, Nova Scotia, Canada Clive P. Duncan, MD, MSc, FRCSC Professor Department of Orthopaedics University of British Columbia Vancouver, British Columbia, Canada John M. Dundon, MD Fellow Department of Orthopedics, Adult Reconstruction New York University New York, New York Randa K. Elmallah, MD Orthopaedic Research Fellow Rubin Institute for Advanced Orthopaedics Sinai Hospital of Baltimore Baltimore, Maryland

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Roger H. Emerson, Jr, MD Director Joint Replacement Institute Texas Health Plano Texas Health Resources Plano, Texas Jeffrey R. Engorn, DO Resident Department of Orthopaedic Surgery The Center for Advanced Orthopedics Larkin Community Hospital South Miami, Florida Thomas K. Fehring, MD Co-Director and Surgeon OrthoCarolina Hip & Knee Center Charlotte, North Carolina Tiffany Feltman, DO Adult Reconstruction Fellow Department of Orthopaedic Surgery Virginia Commonwealth University Health System Richmond, Virginia Andrew N. Fleischman, MD Postdoctoral Research Fellow Department of Orthopaedics Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania Patricia D. Franklin, MD, MBA, MPH Professor Department of Orthopedics and Physical Rehabilitation University of Massachusetts Medical School Worcester, Massachusetts Andrew A. Freiberg, MD Arthroplasty Service Chief and Vice Chair Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts Rajiv Gandhi, MD, MSc, FRCSC Orthopaedic Surgeon, Associate Professor Department of Surgery University of Toronto University Health Network Toronto, Ontario, Canada

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Donald Garbuz, MD, FRCSC Professor and Head Division of Reconstructive Orthopaedics University of British Columbia Vancouver, British Columbia, Canada Kevin L. Garvin, MD Professor and Chair Department of Orthopaedic Surgery and Rehabilitation University of Nebraska Medical Center Omaha, Nebraska Emmanuel Gibon, MD Research Fellow Department of Orthopaedic Surgery Stanford University Stanford, California Andrew H. Glassman, MD, MS Professor and Chairman Department of Orthopaedics The Ohio State University Wexner Medical Center Columbus, Ohio Gregory J. Golladay, MD Associate Professor, Fellowship Director, Adult Reconstruction Department of Orthopaedic Surgery Virginia Commonwealth University Health System Richmond, Virginia

Allan E. Gross, MD, FRCSC Order of Ontario Orthopaedic Surgeon Department of Orthopaedic Surgery Mount Sinai Hospital Professor of Surgery Department of Surgery University of Toronto, Toronto, Ontario, Canada Steven B. Haas, MD Chief Knee Service Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York Fares S. Haddad, FRCS (Orth) Professor Department of Orthopaedic Surgery Institute of Sport, Exercise and Health University College London Hospitals London, England Mohamad J. Halawi, MD Adult Reconstructive Surgery Fellow Department of Orthopaedic Surgery Cleveland Clinic Cleveland, Ohio Erik Hansen, MD Assistant Professor Department of Orthopaedic Surgery University of California San Francisco, California

Stuart B. Goodman, MD, PhD, FRCSC, FACS Professor Department of Orthopaedic Surgery and Bioengineering Stanford University Stanford, California

Amir Herman, MD, PhD Orthopaedic Surgeon Department of Orthopaedic Surgery Tel-Hashomer Medical Center Ramat-Gan, Israel

William L. Griffin, MD Orthopedic Surgeon Department of Orthopedics OrthoCarolina Hip & Knee Center Charlotte, North Carolina

Shane R. Hess, DO Orthopaedic Surgeon Department of Adult Reconstruction The CORE Institute Phoenix, Arizona Daniel J. Holtzman, MD Fellow Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts

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James L. Howard, MD, MSc, FRCS(C) Program Director, Assistant Professor Division of Orthopaedic Surgery Western University, London Health Sciences Centre London, Ontario, Canada William Hozack, MD Annenberg Professor Department of Orthopaedic Surgery Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania Stephen J. Incavo, MD Section Chief, Adult Reconstructive Surgery Department of Orthopaedics and Sports Medicine Houston Methodist Hospital Houston, Texas Richard Iorio, MD Chief of Adult Reconstruction Department of Orthopaedic Surgery NYU Langone Medical Center Hospital for Joint Diseases New York, New York David J. Jacofsky, MD Orthopaedic Surgeon Department of Adult Reconstruction The CORE Institute Phoenix, Arizona William A. Jiranek, MD Professor Department of Orthopaedic Surgery Virginia Commonwealth University Health System Richmond, Virginia Bryan T. Kelly, MD Chief Sports Medicine and Shoulder Service Hospital for Special Surgery New York, New York

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Michael M. Kheir, MD Resident Department of Orthopaedics Indiana University Indianapolis, Indiana Christopher Kim, MD, MSc Department of Orthopaedic Surgery Toronto Western Hospital Toronto, Ontario, Canada Yatin Kirane, MD, PhD Adult Reconstruction Fellow Department of Orthopaedic Surgery Lenox Hill Hospital New York, New York Viktor E. Krebs, MD Vice Chairman Department of Orthopaedic Surgery Cleveland Clinic Cleveland, Ohio Steven M. Kurtz, PhD Research Professor Implant Research Center Drexel University Philadelphia, Pennsylvania Young-Min Kwon, MD, PhD Fellowship Director, Professor Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts Paul F. Lachiewicz, MD Consulting Professor Department of Orthopaedic Surgery Duke University Durham, North Carolina Kyle W. Lacy, MD, MS Arthroplasty Fellow Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts

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Jeffery Lange, MD Orthopaedic Fellow Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York

Adolph V. Lombardi, Jr, MD, FACS Clinical Assistant Professor Department of Orthopaedics Joint Implant Surgeons New Albany, Ohio

Carlos J. Lavernia, MD Director The Center for Advanced Orthopaedics Larkin Community Hospital South Miami, Florida

William J. Long, MD, FRCSC Senior Director Clinical Associate Professor NYU Langone Medical Center Insall Scott Kelly Institute New York, New York

Cameron K. Ledford, MD Lower Extremity Reconstruction Fellow Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota Gwo-Chin Lee, MD Associate Professor Department of Orthopaedic Surgery University of Pennsylvania Philadelphia, Pennsylvania Yadin D. Levy, MD Adult Reconstruction and Joint Replacement Fellow Specialist Orthopaedic Group Mater Clinic Sydney, New South Wales, Australia David G. Lewallen, MD Professor of Orthopedic Surgery Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota Guoan Li, PhD Director, The Bioengineering Laboratory Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts Jay R. Lieberman, MD Professor and Chairman Department of Orthopaedic Surgery Keck School of Medicine of University of Southern California Los Angeles, California

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Jess H. Lonner, MD Associate Professor Department of Orthopaedic Surgery Sidney Kimmel Medical College Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania Steven J. MacDonald, MD, FRCSC Professor, Chairman Department of Orthopaedic Surgery University of Western Ontario London, Ontario, Canada Nizar N. Mahomed, MD, MPH, ScD Professor Department of Surgery Toronto Western Hospital University of Toronto Toronto, Ontario, Canada Arthur L. Malkani, MD Chief Adult Reconstruction Clinical Professor Department of Orthopedics University of Louisville Louisville, Kentucky William J. Maloney, MD Professor and Chairman Department of Orthopaedic Surgery Stanford University, School of Medicine Redwood City, California Dean J. Marshall, DO Clinical Fellow Department of Hip and Knee Reconstruction Joint Implant Surgeons New Albany, Ohio © 2017 American Academy of Orthopaedic Surgeons

Bassam A. Masri, MD, FRCSC Professor and Chairman Department of Orthopaedics University of British Columbia Vancouver, British Columbia, Canada James P. McAuley, MD, FRCS(C) Professor Department of Orthopaedic Surgery Western University London, Ontario, Canada

Bernard F. Morrey, MD Professor of Orthopedic Surgery, Mayo Clinic Clinical Professor, Shoulder & Elbow Total Joint Arthroplasty, University of Texas Health Science Center Department of Orthopedics Mayo Clinic Rochester, Minnesota The University of Texas Health Science Center at San Antonio San Antonio, Texas

Richard W. McCalden, MD, MPhil (Edin.), FRCS(C) Professor of Surgery Western University Division of Orthopaedic Surgery London Health Sciences Centre London, Ontario, Canada

Matthew C. Morrey, MD, MS Adjunct Associate Professor Department of Adult Reconstruction and Orthopedics The University of Texas Health Science Center at San Antonio San Antonio, Texas

R. Michael Meneghini, MD Associate Professor Department of Orthopaedic Surgery Indiana University School of Medicine Indianapolis, Indiana

Orhun K. Muratoglu, PhD Co-Director, Harris Orthopaedic Lab, Massachusetts General Hospital Professor, Harvard Medical School Department of Orthopaedic Surgery Massachusetts General Hospital Harvard Medical School Boston, Massachusetts

William M. Mihalko, MD, PhD Professor Department of Orthopaedic Surgery Campbell Clinic JR Hyde Chair of Excellence in Biomechanical Engineering University of Tennessee Health Science Center University of Tennessee Memphis, Tennessee Jaydev B. Mistry, MD Orthopaedic Research Fellow Center for Joint Preservation and Replacement Rubin Institute for Advanced Orthopaedics, Sinai Hospital of Baltimore Baltimore, Maryland Michael A. Mont, MD Chairman Department of Orthopaedic Surgery Cleveland Clinic Foundation Cleveland, Ohio

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James Nace, DO, MPT Orthopaedic Surgeon Center for Joint Preservation and Replacement Rubin Institute for Advanced Orthopaedics, Sinai Hospital of Baltimore Baltimore, Maryland Abbas Naqvi, MD Resident Department of Orthopaedic Surgery Howard University Hospital Washington, District of Columbia Philip C. Noble, PhD Professor Joseph Barnhart Department of Orthopaedic Surgery Baylor College of Medicine Houston, Texas

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Andrew B. Old, MD Fellow Department of Orthopaedic Surgery NYU Langone Medical Center New York, New York

Christopher L. Peters, MD Professor Department of Orthopaedics University of Utah Salt Lake City, Utah

Ebru Oral, PhD Assistant Professor Department of Orthopaedic Surgery Massachusetts General Hospital, Harvard Medical School Boston, Massachusetts

Luis F. Pulido, MD Orthopaedic Surgeon Department of Orthopedics and Sports Medicine Houston Methodist Hospital Houston, Texas

Feroz Osmani, BS Research Fellow Department of Orthopaedic Surgery NYU Langone Medical Center, Hospital for Joint Diseases New York, New York

James J. Purtill, MD Vice Chairman Department of Orthopaedic Surgery Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania

Douglas E. Padgett, MD Chief, Adult Reconstruction and Joint Replacement Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York

Rohit Rambani, MBBS, MS Ortho, FIMSA, FRCS Consultant, Orthopaedics Department of Orthopaedics United Lincolnshire Hospital NHS Trust Boston, Lincolnshire, England

Mark W. Pagnano, MD Professor and Chairman Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota

Amar Ranawat, MD Surgeon Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York

Javad Parvizi, MD, FRCS Professor, Director, Vice Chairman of Research Department of Orthopaedic Surgery Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania

Anil Ranawat, MD Surgeon Department of Sports Medicine and Joint Preservation Hospital for Special Surgery New York, New York

Nirav K. Patel, MD, FRCS Clinical Fellow Center for Joint Preservation and Replacement Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore Baltimore, Maryland

Andrew B. Richardson, MD Adult Hip and Knee Reconstruction Fellow Joint Implant Surgeons New Albany, Ohio

Colin T. Penrose, MD Resident Department of Orthopaedic Surgery Duke University Medical Center Durham, North Carolina

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Michael D. Ries, MD Professor Emeritus Department of Orthopaedic Surgery University of California, San Francisco San Francisco, California

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Martin Roche, MD Robotics Director Department of Orthopedic Surgery Holy Cross Orthopedic Institute Fort Lauderdale, Florida

Emil Schemitsch MD, FRCS(C) Richard Ivey Professor and Chairman Department of Surgery Western University London, Ontario, Canada

Harry E. Rubash, MD Chief of Orthopaedic Surgery Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts

W. Norman Scott, MD, FACS Clinical Professor, NYU Langone Medical Center Founding Director, Insall Scott Kelly Institute for Orthopaedics and Sports Medicine Department Orthopaedic Surgery, NYU Langone Medical Center Department of Orthopaedics and Sports Medicine, Insall Scott Kelly Institute for Orthopaedics and Sports Medicine NYU Langone Medical Center Hospital for Joint Diseases New York, New York

Robert Russell, MD Surgeon Department of Orthopedics W.B. Carrell Clinic Dallas, Texas Christopher Samujh, MD Staff Surgeon Department of Orthopedics Scranton Orthopaedic Specialists Dickson City, Pennsylvania Adam A. Sassoon, MD, MS Assistant Professor Department of Orthopaedic Surgery University of Washington Seattle, Washington Jibanananda Satpathy, MD, MRCSEd Assistant Professor Department of Adult Reconstruction and Orthopaedics Virginia Commonwealth University Health System Richmond, Virginia Siraj A. Sayeed, MD, MEng President South Texas Bone and Joint Institute San Antonio, Texas Yousuf Sayeed, MS Research Fellow Department of Orthopedics, Adult Reconstruction New York University New York, New York

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Giles R. Scuderi, MD Northwell Health Orthopaedic Institute Department of Orthopaedic Surgery Lenox Hill Hospital New York, New York Peter K. Sculco, MD Assistant Attending Orthopaedic Surgeon Department of Adult Reconstruction and Joint Replacement Hospital for Special Surgery New York, New York Thomas P. Sculco, MD Attending Orthopaedic Surgeon Professor of Orthopaedic Surgery Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York Bryan D. Springer, MD Fellowship Director OrthoCarolina Hip & Knee Center Charlotte, North Carolina S. David Stulberg, MD Clinical Professor, Orthopaedic Surgery Department of Orthopaedic Surgery Northwestern University, Feinberg School of Medicine Chicago, Illinois

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Eric Szczesniak, MD Clinical Fellow Department of Orthopaedic Surgery, Adult Hip and Knee Reconstruction Rubin Institute for Advanced Orthopaedics Baltimore, Maryland Michael Tanzer, MD, FRCSC Jo Miller Chair and Professor of Surgery Division of Orthopaedic Surgery McGill University Montreal, Quebec, Canada Savyasachi C. Thakkar, MD Adult Reconstruction Surgery Fellow Department of Orthopaedic Surgery New York University, Hospital for Joint Diseases New York, New York Gregory A. Tocks, DO Adult Reconstruction Fellow Department of Orthopaedic Surgery Virginia Commonwealth University Richmond, Virginia

Bradford S. Waddell, MD Fellow Department of Adult Reconstruction Hospital for Special Surgery New York, New York William L. Walter, MBBS, PhD Assistant Professor, Orthopaedic Surgeon Mater Hospital Department of Orthopaedics Wollstonecraft, New South Wales, Australia Derek Ward, MD Fellow Department of Adult Reconstruction Rothman Institute at Thomas Jefferson University Philadelphia, Pennsylvania Jennifer S. Wayne, PhD Professor Department of Biomedical Engineering Virginia Commonwealth University Richmond, Virginia

Robert T. Trousdale, MD Professor of Orthopedic Surgery Department of Orthopedic Surgery Mayo Clinic Rochester, Minnesota

Geoffrey Westrich, MD Surgeon, Adult Reconstruction and Joint Replacement Department of Orthopaedic Surgery Hospital for Special Surgery New York, New York

Slif D. Ulrich, MD Adult Reconstruction Fellow Department of Orthopedics University of Louisville Louisville, Kentucky

Geoffrey P. Wilkin, MD, FRCSC Assistant Professor Division of Orthopaedic Surgery University of Ottawa Ottawa, Ontario, Canada

Kartik Mangudi Varadarajan, PhD Assistant Director, Technology Implementation Research Center Department of Orthopaedic Surgery Massachusetts General Hospital Boston, Massachusetts

Joseph L. Yellin, MD Resident Harvard Combined Orthopaedic Residency Program Harvard University Boston, Massachusetts

Kelly G. Vince, MD, FRCSC Consultant Surgeon Department of Orthopedic Surgery Northland District Health Board Whangarei, New Zealand

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Preface Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5 complements and updates information that was published in the four previous editions. The first edition was published in 1995, the second in 2000, the third in 2006, and the fourth in 2011. This edition encompasses a comprehensive review of the past 5 years of published literature on hip and knee arthroplasty. This fifth edition serves as an update that can stand on its own. This edition should provide residents, fellows, and practicing orthopaedic surgeons with a clear understanding of the state-of-the-art knowledge relevant to adult hip and knee reconstruction. As with the previous four publications, it can be used as a resource for both general orthopaedic surgeons as well as hip and knee specialists. The fifth edition, like the fourth edition, is composed of three distinct sections: basic and applied science relevant to both knee and hip arthroplasty; specific total knee arthroplasty topics; and specific total hip arthroplasty topics. There is updated material related to controversial topics and

© 2017 American Academy of Orthopaedic Surgeons

state-of-the-art technologies. All of the chapters have been written by experts in each subject, with a concerted effort to reflect the current state of hip and knee reconstruction knowledge with objectivity and a minimal amount of personal bias by basing material primarily on evidence-based information from these recent reports. We, the editors, would like to thank all of the authors for their efforts to complete their chapters, and putting up with our relentless constructive criticism. We also gratefully acknowledge the invaluable assistance of the Publications Department of the American Academy of Orthopaedic Surgeons. This includes Hans Koelsch, PhD, Director; Lisa Claxton Moore, Senior Manager, Book Program; Steven Kellert, Senior Editor; Courtney Dunker, Editorial Production Manager; Abram Fassler, Publishing Systems Manager; and Sylvia Orellana, Publications Assistant. Their work and diligence helped to make this book of the highest quality. Michael A. Mont, MD Michael Tanzer, MD, FRCSC

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Table of Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Section 1: Hip and Knee Editors: Michael A Mont, MD and Michael Tanzer, MD, FRCSC

Chapter 1 Imaging of the Hip and Knee for Primary and Revision Arthroplasty Luis F. Pulido, MD; Stephen J. Incavo, MD . . . . . 3

Chapter 2 Perioperative Assessment and ­Management Jay R. Lieberman, MD; Ram K. Alluri, MD . . . . . . . . . . . . . . . . . . . . . . 15

Chapter 3 Blood Management Yatin Kirane, MD, PhD; Fred D. Cushner, MD . . . . . . . . . . . . . . . . . . . . . 27

Chapter 4 Osteonecrosis of the Hip and Knee Nirav K. Patel, MD, FRCS; Jaydev B. Mistry, MD; Randa K. Elmallah, MD; Morad Chughtai, MD; James Nace, DO, MPT; Michael A. Mont, MD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Chapter 5 Economics and Cost Implications of Total Hip and Total Knee Arthroplasty Richard Iorio, MD; Feroz Osmani, BS; Savyasachi C. Thakkar, MD . . . . . . . . . . . . . . . . 63

Chapter 6 National Joint Registries Daniel J. Berry, MD; David G. Lewallen, MD; Fares S. Haddad, FRCS (Orth) . . . . . . . . . . . . . . 73

Section 2: Knee Editor: Michael A. Mont, MD

Chapter 7 Biomechanics of the Knee Gregory A. Tocks, DO; William A. Jiranek, MD; Jibanananda Satpathy, MD, MRCSEd; Jennifer S. Wayne, PhD . . . . . . . . . . . . . . . . . . . 85

Chapter 8 Minimally Invasive Surgical Approaches to Knee Arthroplasty Giles R. Scuderi, MD; Henry D. Clarke, MD; Christopher A. Dodd, FRCS . . . . . 95

Chapter 9 Kinematics in Total Knee Arthroplasty William M. Mihalko, MD, PhD . . . . . . . . . . . . 105

Chapter 10 Implant Designs of Total Knee ­Arthroplasty Kartik Mangudi Varadarajan, PhD; Daniel J. Holtzman, MD; Guoan Li, PhD; Jeffrey Lange, MD; Steven B. Haas, MD; Harry E. Rubash, MD; ­ Andrew A. Freiberg, MD . . . . . . . . . . . . . . . . . 113

Chapter 11 Special Considerations in Primary Total Knee Arthroplasty Andrew B. Old, MD; William J. Long, MD, FRCSC; W. Norman Scott, MD, FACS . . . . . . . . . . . . . 131

Chapter 12 Bicruciate-Retaining Total Knee ­Arthroplasty Justin G. Brothers, MD; Christopher L. Peters, MD . . . . . . . . . . . . . . . . 143

Chapter 13 Unicompartmental, Patellofemoral, and Bicompartmental Knee Arthroplasty Mohamad J. Halawi, MD; Joseph L. Yellin, MD; Anil Ranawat, MD; Jibanananda Satpathy, MD, MRCSEd; Gregory J. Golladay, MD; Jess H. Lonner, MD; Wael K. Barsoum, MD . . . . . . . . . . . . . . . 149

Chapter 14 Robotic-Assisted Knee Arthroplasty Martin Roche, MD . . . . . . . . . . . . . . . . . . . . . 163

Chapter 15 Computer-Assisted Knee Arthroplasty S. David Stulberg, MD; Michael Dunbar, MD, FRCSC, PhD; Gwo-Chin Lee, MD . . . . . . . . . . 173

Chapter 16 The Difficult Primary Total Knee ­Arthroplasty Jaydev B. Mistry, MD; Siraj A. Sayeed, MD, MEng; Morad Chughtai, MD; Randa K. Elmallah, MD; Michael A. Mont, MD; Ronald E. Delanois, MD . . . . . . . . . . . . . . . . . 183

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Chapter 17 Management of Extra-Articular ­Deformities in Knee Arthroplasty Abbas Naqvi, MD; Jaydev B. Mistry, MD; Randa K. Elmallah, MD; Morad Chughtai, MD; Michael A. Mont, MD . . . . . . . . . . . . . . . . . . . 197

Chapter 18 Outcomes of Primary Total Knee ­Arthroplasty David C. Ayers, MD; Patricia D. Franklin, MD, MBA, MPH; Rajiv Gandhi, MS, MD, FRCSC; Christopher Kim, MD, MSc; Jeffrey Lange, MD; ­Nizar N. Mahomed, MD, MPH, ScD; Philip C. Noble, PhD . . . . . . . . . . . . . . . . . . . . 207

Chapter 19 Outpatient Total Knee Arthroplasty Adolph V. Lombardi, Jr, MD, FACS; Dean J. Marshall, DO . . . . . . . . . . . . . . . . . . . 223

Chapter 20 Complications of Knee Arthroplasty Viktor E. Krebs, MD; Arthur L. Malkani, MD; Slif D. Ulrich, MD; David Backstein, MD, MEd, FRCSC; Mansour Abolghasemian, MD; Bryan D. Springer, MD; Christopher Samujh, MD . . . . . . . . . . . . . . . . . 233

Chapter 21 Revision Total Knee Arthroplasty R. Michael Meneghini, MD; Kelly G. Vince, MD, FRCSC; Bradford S. Waddell, MD; Geoffrey Westrich, MD . . . . . . . . . . . . . . . . . . 267

Chapter 22 Perioperative Pain Management in Knee Arthroplasty Colin T. Penrose, MD; John W. Barrington, MD . . . . . . . . . . . . . . . . . 279

Chapter 23 Retrieval Analysis of Knee Prostheses Steven M. Kurtz, PhD; Jaydev B. Mistry, MD; Eric Szczesniak, MD; Randa K. Elmallah, MD; Morad Chughtai, MD; Michael A. Mont, MD . . . . . . . . . . . . . . . . . . . 291

Chapter 24 Nonarthroplasty Management of Knee Arthritis David J. Jacofsky, MD; Shane R. Hess, DO . . . . . . . . . . . . . . . . . . . . . . 299

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

Section 3: Hip Editor: Michael Tanzer, MD, FRCSC

Chapter 25 Arthroplasty Management of Hip ­Fractures: Hemiarthroplasty Versus Total Hip Arthroplasty—Results and ­Complications Michael Tanzer, MD, FRCSC . . . . . . . . . . . . . . 313

Chapter 26 Nonarthroplasty Joint-Preserving Surgery for Hip Disorders Paul E. Beaulé, MD, FRCSC; J.W. Thomas Byrd, MD; Geoffrey P. Wilkin, MD, FRCSC; Bryan T. Kelly, MD; Sasha Carsen, MD, MBA, FRCSC; ­Hussain Al-Yousif, MD; Benjamin R. Coobs, MD; John C. Clohisy, MD . . . . . . . . . . 321

Chapter 27 Alternatives to Conventional Total Hip Arthroplasty for Osteoarthritis Adam A. Sassoon, MD, MS; William J. Maloney, MD; John C. Clohisy, MD . . . . . . . . . . . . . . . . 339

Chapter 28 Surgical Approaches and Bearing Surfaces William Hozack, MD; Clive P. Duncan, MD, MSc, FRCSC; Amir Herman, MD, PhD; Erik Hansen, MD; Mark W. Pagnano, MD; James L. Howard, MD, MSc, FRCS(C); James P. McAuley, MD, FRCS(C); William A. Jiranek, MD; Tiffany Feltman, DO; Orhun K. Muratoglu, PhD; Ebru Oral, PhD; Gregory K. Deirmengian, MD; William L. Walter, MBBS, PhD; Yadin D. Levy, MD; Richard W. McCalden, MD, MPhil (Edin.), FRCS(C); Emil Schemitsch, MD, FRCS(C) . . . . . . . . . . . . . . . . 345

Chapter 29 The Biologic Response to Bearing ­Materials Emmanuel Gibon, MD; Stuart B. Goodman, MD, PhD, FRCSC, FACS . . . . . . . . 367

Chapter 30 Primary Total Hip Arthroplasty Craig J. Della Valle, MD; Daniel J. Berry, MD; Charles R. Bragdon, PhD; John J. Callaghan, MD; Rocco D’Apolito, MD; Douglas A. Dennis, MD; Ivan De Martino, MD; Roger H. Emerson, Jr, MD; Andrew A. Freiberg, MD; Young-Min Kwon, MD, PhD; Kyle W. Lacy, MD, MS; Steven J. MacDonald, MD, FRCSC; R. Michael Meneghini, MD; Matthew C. Morrey, MD, MS; Bernard F. Morrey, MD; Amar Ranawat, MD; Harry E. Rubash, MD; Thomas P. Sculco, MD . . . . . . . . . . . . . . . . . . . 377

© 2017 American Academy of Orthopaedic Surgeons

Chapter 31 Primary Total Hip Arthroplasty in Challenging Conditions Andrew H. Glassman, MD, MS; Michael Tanzer, MD, FRCSC; Richard Iorio, MD; John M. Dundon, MD; Yousuf Sayeed, MS; Mathias P.G. Bostrom, MD; Michael D. Ries, MD; Robert T. Trousdale, MD; Nicholas M. Desy, MD, FRCSC . . . . . . . . . . . . 393

Chapter 32 Computer Navigation and Robotics in Total Hip Arthroplasty Bradford S. Waddell, MD; Douglas E. Padgett, MD . . . . . . . . . . . . . . . . . . 423

Chapter 35 Complications of Total Hip Arthroplasty Michael M. Kheir, MD; Javad Parvizi, MD, FRCS; Andrew N. Fleischman, MD; Anthony Albers, MDCM, FRCSC; Clive P. Duncan, MD, MSc, FRCSC; Bassam A. Masri, MD, FRCSC; Derek Ward, MD; Keith R. Berend, MD; Matthew S. Austin, MD; Peter K. Sculco, MD; Thomas K. Fehring, MD; David M. Beck, MD; James J. Purtill, MD; Jeffrey R. Engorn, DO; Carlos J. Lavernia, MD . . . . . . . . . . . . . . . . . . 473

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507

Chapter 33 Rapid Recovery in Total Hip Arthroplasty Adolph V. Lombardi, Jr, MD, FACS; Andrew B. Richardson, MD; Kevin L. Garvin, MD . . . . . . 437

Chapter 34 Revision Total Hip Arthroplasty Anthony Albers, MD, FRCSC; Alberto Carli, MD, MSc, FRCSC; Sachin Daivajna, MS, FRCS (Orth); William L. Griffin, MD; Robert Russell, MD; Allan E. Gross, MD, FRCSC; Paul F. Lachiewicz, MD; Cameron K. Ledford, MD; David G. Lewallen, MD; Douglas E. Padgett, MD; Rohit Rambani, MBBS, MS Ortho, FIMSA, FRCS, Tr & Orth; Donald Garbuz, MD, FRCSC . . . . 453

© 2017 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

xxi

CELEBRATING 45 YEARS OF

EMS Education AND Innovation In 1971, the American Academy of Orthopaedic Surgeons (AAOS) published the first edition of Emergency Care and Transportation of the Sick and Injured and laid the foundation of EMS training. In 1997, the AAOS partnered with Jones & Bartlett Learning to release t he revised sixth edition. Since the publication of that edition, the AAOS and Jones & Bartlett Learning have worked together to transform all levels of EMS training, from emergency medical responder to paramedic. Today, in partnership with Jones & Bartlett Learning, the AAOS’s commitment and dedication to excellence has transformed how EMS education is delivered throughout the world and helped develop and train countless world-class EMS providers. More than 45 years later, this acclaimed resource continues to set the standard in EMS education.

www.EMT11e.com

Advanced Reconstruction: Hip 2 Master the latest techniques

Daniel J. Berry, MD, and Jay R. Lieberman, MD, Editors

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Text plus Online Video! This new edition presents expert insight and practical guidance for 70+ surgical challenges, spanning primary, complex, and revision total hip arthroplasty, complications, and alternative procedures.

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Chapter 1

Imaging of the Hip and Knee for Primary and Revision Arthroplasty Luis F. Pulido, MD  Stephen J. Incavo, MD

Abstract

Keywords: hip arthroplasty; knee arthroplasty; diagnostic imaging in arthroplasty; nuclear medicine; digital radiographs in arthroplasty

Dr. Incavo or an immediate family member has received royalties from Biomet, Innomed, Smith & Nephew, Wright Medical Technology, and Zimmer, serves as a paid consultant to Zimmer, has stock or stock options held in Zimmer, and serves as a board member, owner, officer, or committee member of the Knee Society. Neither Dr. Pulido nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

The myriad diagnostic imaging modalities currently available are important tools for the diagnosis and treatment of patients with musculoskeletal disorders, including patients undergoing hip and knee arthroplasty. The digitization of radiographs with picture archiving and communication systems has improved the storage of and access to medical images. Plain radiographs are the first-line diagnostic test in orthopaedics. A methodic approach to the evaluation of hip and knee radiographs is usually sufficient to determine a diagnosis and establish a treatment plan. Preoperative planning using digital templating of calibrated radiographs aids the accuracy and efficiency of total hip and total knee arthroplasty. Recent advances in other imaging techniques such as low-dose radiation systems, nuclear medicine, ultrasonography, CT, and MRI have a complementary role in the evaluation of different clinical scenarios before and after hip and knee arthroplasty.

Introduction The myriad diagnostic imaging modalities available are important tools for the diagnosis and management of musculoskeletal disorders, including for patients undergoing hip and knee arthroplasty. Picture archiving and communication systems have improved the storage of and access to digitized radiography. Plain radiographs are used as the first-line diagnostic test in orthopaedics. A methodic approach to the evaluation of hip and knee radiographs is usually sufficient to determine a diagnosis and establish a treatment plan. The accuracy and efficiency of total hip arthroplasty (THA) and total knee arthroplasty (TKA) is increased using digital templates of calibrated radiographs. Recent advances in other imaging techniques such as low-dose radiation imaging systems, nuclear medicine, ultrasonography, CT, and MRI have a complementary role in the clinical evaluation patients before and after hip and knee arthroplasty. The use of digital radiographs is important in the evaluation and preoperative planning of primary and revision THA and TKA. The advances and clinical usefulness of newer diagnostic imaging tests are discussed, including the supplementary role of modern nuclear medicine in the evaluation of the painful total joint arthroplasty and the use of ultrasonography in patients with hip disorders or in whom hip arthroplasty was unsuccessful. In addition, the role of advanced imaging such as CT in the evaluation of implant position, osteolysis, and bone loss after hip and knee arthroplasty, as well as the use of modern MRI modalities in the evaluation of hip and knee osteochondral lesions and periprosthetic soft-tissue injuries or adverse soft-tissue reactions are also reviewed. Radiographs are the initial diagnostic test used for the evaluation of patients with hip and knee problems. Weight-bearing views provide a more reliable evaluation of limb alignment and joint space narrowing in patients with hip and knee osteoarthritis.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

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Section 1: Hip and Knee

1: Hip and Knee

Preoperative Planning and Digital Templating Digital templating is an important tool in planning primary and revision THA.1 Digital implant template overlay helps determine the best implant fit, size, and position with the goal of restoring hip biomechanics. Restoration of the normal center of rotation, the femoral lateral offset, and leg lengths are important goals to achieve in the preoperative planning and execution of THA. A methodical, stepwise approach for templating THA is described in Figure 1.

Figure 1

Weight-bearing AP pelvic radiograph with lower extremities in 10 to 15° of internal rotation demonstrates stepwise approach for templating total hip arthroplasty. (1) Digital image is calibrated with markers. (2) Pelvic axis orientation is determined using a line (long orange) across the teardrops. (3) Leg lengths are determined using the distance from a line (short orange) perpendicular to the pelvic axis and the tops of the lesser or greater trochanters. (4) The acetabular component (blue outline) is placed to restore the hip center of rotation with the cup apex just lateral to the teardrop at 40° to 45° of abduction from the pelvic axis. (5) The femoral component (blue outline) is templated to determine the best fitting stem and stem sizes to restore femoral lateral offset and equalize leg lengths.

Total Hip Arthroplasty Standard views for the evaluation of hip disorders include a weight-bearing AP view of the pelvis and AP and cross-table lateral views of the hip. The proper technique to obtain a pelvic AP view for accurate determination of neck length and femoral lateral offset includes directing the x-ray beam perpendicularly and centered on a midpoint between the symphysis pubis and the anterior superior iliac spine with the lower extremities in 10° to 15° of internal rotation. The cross-table lateral radiograph is obtained with the patient supine, the contralateral hip flexed, and the affected limb in 15° of internal rotation and the x-ray beam oriented at 45° to the affected hip. Other hip radiographic views such as the frog-leg lateral, Dunn views, and false profile views are recommended in the evaluation of the young adult (age 15 to 45 years) with hip pain resulting from femoroacetabular impingement and hip dysplasia. Judet views are supplemental in the evaluation of pelvic bone loss and column integrity in acetabular revision.

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

Hip Dysplasia Preoperative planning for THA in patients with end-stage hip disease resulting from hip dysplasia has unique acetabular and femoral anatomic features. Plain radiographs are sufficient for surgical planning and digital templating. The dysplastic acetabulum is small, shallow, steep, and elongated.2 The cup should ideally be placed at the hip’s true center of rotation. Femoral head autograft can be used to reconstitute large superolateral acetabular defects. The use of a high hip center is less favorable because of abnormal hip biomechanics, increased joint reaction forces, and increased risk of failure. The dysplastic femur has a high femoral neck-shaft angle with increased femoral anteversion. The use of a femoral stem that allows adjustment of femoral version is preferable.3 This can be accomplished with a cemented or modular noncemented stem. A subtrochanteric shortening osteotomy is useful for the management of hip dysplasia with high-grade dislocation to avoid iatrogenic stretch injury to the peroneal-­ sciatic nerve4 (Figure 2). Femoral Deformity Biplanar radiographs with magnification markers of the pelvis and entire femur are recommended in the surgical planning of THA in patients with proximal femoral deformity. Digital templating helps plan the management of different deformity sites (greater trochanter, femoral neck, metaphysis, and diaphysis) and types (angular, translational, and torsional). The use of modular stems with distal stability or fixation may become more important in this clinical scenario. Pelvic Obliquity The pelvic axis orientation is corrected during preoperative templating and surgical completion of THA for accurate acetabular abduction angle placement and leg length equalization. In most cases, restoration of the coronal balance of the pelvis following THA is associated with compensation of the coronal alignment of the spine. As a result, spinal imbalance and back pain can worsen in some patients with rigid degenerative scoliosis

© 2017 American Academy of Orthopaedic Surgeons

Chapter 1: Imaging of the Hip and Knee for Primary and Revision Arthroplasty

1: Hip and Knee

Figure 2

A, Preoperative AP pelvic radiograph in a young patient with hip dysplasia and high-grade dislocation (CroweRanawat stage IV). B, Postoperative AP pelvic radiograph obtained following complex noncemented total hip arthroplasty. The noncemented acetabular implant was placed to restore the hip center of rotation.

following THA.5 Weight-bearing radiographs obtained using a block on the shortened leg can help determine the target for any planned leg lengthening. Any pelvic obliquity resulting from rigid scoliosis, if corrected, will result in spinal imbalance and should be avoided. Pelvic Tilt Lumbopelvic lordosis and kyphosis present a challenge in THA because pelvic tilt determines functional anteversion and inclination of the acetabulum. Sagittal lumbopelvic plane deformities can be rigid or flexible. Pelvic tilt varies during simple activities such as standing, sitting, or lying down, which makes functional acetabular position a difficult, mobile target when considered in the setting of THA. Recently, interest has been generated in adjustment of the acetabular component position based on the functional pelvic tilt seen on weight-bearing radiographs.6 Revision THA The key principle in revision surgery is understanding the cause of failure and determining a successful treatment plan. The most common causes of failure after hip arthroplasty include aseptic loosening, instability, osteolytic wear, periprosthetic fractures, and deep infection.7 Plain radiographs allow evaluation of the type of prosthesis, implant position, fixation, wear, periprosthetic bone loss,

© 2017 American Academy of Orthopaedic Surgeons

and fractures. Preoperative templating is also an important aspect of revision THA. Implants Plain radiographs are used to determine the type of femoral and acetabular implants as well as bearing surfaces. The poor performance of certain hip implants warns about specific causes and mechanisms of failure after THA. Weight-bearing AP pelvic and cross-table lateral views are used to evaluate acetabular and femoral component malposition. The etiology of hip instability is multifactorial, and problems such as lack of femoral offset, excessive acetabular inclination, and version abnormalities can be seen on plain radiographs. Iliopsoas impingement resulting from retroverted acetabular components with prominent, uncovered metal anteriorly results in a painful hip following arthroplasty and is easily evaluated using the cross-table lateral view. Sequential radiographic evaluation can be extremely helpful to determine femoral and acetabular fixation with and without cement. Osteolysis and Bone Loss Plain radiographic findings tend to underestimate periprosthetic osteolysis and bone loss. However, in the setting of mechanical failure and migration of the acetabular component, AP pelvic, cross-table lateral, and Judet views can help assess major segmental bone defects and the

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1: Hip and Knee

Section 1: Hip and Knee

Figure 3

AP radiographs of the left hip of a 64-year-old man who had undergone femoral revision for periprosthetic femur fracture complicated by a deep prosthetic joint infection and a chronic draining sinus. A, Preoperative view used to plan length and type of osteotomy to remove a well-fixed noncemented modular titanium stem. B, Postoperative view obtained following posterior extended trochanteric osteotomy, removal of hip implants, placement of highdose antibiotic cement dynamic spacer, and extended trochanteric osteotomy reduction with wires.

presence of pelvic discontinuity.8 The evaluation of femoral diaphyseal bone loss on radiographs is important in preoperative planning to help define the method used for femoral revision. The quality and length of the isthmus is evaluated because distally fixed tapered modular fluted titanium stems have been universally adopted in femoral revision because of superior clinical results and versatility.9 Extended Trochanteric Osteotomy Plain radiographs are needed to determine the need for, type, and length of a femoral osteotomy. An extended trochanteric osteotomy is important to facilitate implant removal, cement removal, and femoral revision (Figure 3). Total Knee Arthroplasty The standard knee radiographic series includes a weight-bearing AP view obtained with neutral rotation of the limbs, a lateral view with the knee flexed 30°, and a Merchant axial view. The advantage of a full-length weight-bearing AP view of the lower extremity over shorter images is that it allows more precise measurement of

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

knee anatomic and mechanical axes. These images also provide evidence of possible hip disorders, which must be ruled out in all painful knees, and help identify any deformities of the femur and/or tibia. The axial alignment of the knee seen in two-dimensional (2D) frontal views is influenced by the lower extremity rotation. Excessive internal rotation simulates valgus alignment, and excessive external rotation simulates varus alignment.10 A 30° weight-bearing flexion view helps to more accurately determine joint space narrowing in the native knee. In primary TKA, digital templates allow assessment of a deformity and help plan the correction using femoral and tibial bone cuts to restore mechanical axis. Digital templating also allows determination of the femoral implant size to restore posterior condylar offset and avoid notching. A stepwise approach for templating TKA should be followed. First, the digital image is calibrated with markers. For the lateral view, the size of the femoral implant on the lateral view to restore posterior condylar offset and avoid anterior notching should be established. Next, sagittal femoral bowing, patellar height, and tibial slope should be assessed. For the AP view (long leg or short knee), the mechanical axis should be determined on AP view. Distal femoral and proximal tibia resection angles should be planned to restore the mechanical axis, depending on the surgeon’s preferred technique. Long leg radiographs are important to obtain in patients with extra-articular deformity (Figure 4). Revision TKA Aseptic loosening, instability, malalignment, and periprosthetic joint infection are the most common causes of failure after TKA.11 Plain radiographs are used to help determine the cause of failure, for surveillance, and for surgical planning. Implant Position The knee implant position can be determined using the standard knee series views noted previously. Neutral, varus, or valgus alignment of the femur and tibia is determined using coronal AP views. The lateral knee radiographs help determine the amount of tibial slope, posterior femoral offset, and sagittal position of the femoral implant. In revision TKA for flexion instability or in patients with flexion contracture, the distance from the medial epicondyle to the femoral joint line is measured to determine if the femoral component is too distal. The posterior femoral offset and tibial slope are also measured on the lateral radiographs and corrected in revision surgery for flexion instability.12

© 2017 American Academy of Orthopaedic Surgeons

Chapter 1: Imaging of the Hip and Knee for Primary and Revision Arthroplasty

Figure 4

Implant Fixation Standard knee views, sequential radiographs, and occasionally, fluoroscopic views, can help determine femoral and tibial loosening after TKA. The size, percentage, and location of radiolucent lines help determine loosening. Technologies such as radiostereometric analysis are more accurate to measure implant migration after TKA. Radiostereometric analysis has limited clinical use and is mainly used for clinical research. Advanced Imaging Techniques Digital Radiographic Imaging Systems New and advanced imaging technologies such as the EOS imaging system (EOS Imaging) provides functional radiographic information in different positions such as standing, squatting, and sitting. The role of low-dose radiation imaging in THA has not been established; however, 2D and three-dimensional (3D) functional images obtained with low-dose radiation imaging are important in determining the hip-spine relationship in THA. The EOS imaging system is capable of providing weight-bearing biplanar digital radiographs and 3D reconstructions of the entire body. The EOS imaging system consists of two pairs of perpendicularly positioned, vertically moving, linked units of x-ray tubes that produce thin collimated x-ray beams collected by the detectors, resulting in simultaneous, spatially calibrated weight-bearing AP and lateral images. Static functional views in standing, sitting, or squatting positions (Figure 5) can be obtained in 10 to 25 seconds with a fraction of the radiation used with plain radiographs (sixfold to ninefold reduction in radiation) or CT (600-fold reduction in radiation). The EOS system also can create 3D reconstruction

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

Lateral (A) and full-length bilateral AP weight-bearing (B) radiographs demonstrate right knee degenerative joint disease with associated right femoral extra-articular deformity. AP (C) and lateral (D) radiographs of the right knee demonstrate successful simultaneous total knee arthroplasty and deformity correction with femoral osteotomy and retrograde nail fixation.

models of the spine, pelvis, and lower limbs.13,14 In THA, the EOS system can be used to accurately determine the acetabular position. However, this system is limited when used in the evaluation of periprosthetic loosening and osteolysis. The potential role for the EOS system in THA includes the evaluation and planning of the functional position of the acetabulum relative to the lumbopelvic changes during standing and sitting positions.14,15 Multidetector CT Multidetector CT is superior to plain radiography and can be used as a supplementary diagnostic test to help diagnose prearthritic conditions of the hip as well as hip and knee implant fixation, loosening, position, and periprosthetic bone loss. Multidetector CT has improved efficiency and imaging quality compared with conventional CT. Narrower collimation and low pitch adjustments in multidetector CT reduces metal artifacts and improves the image quality of bone and soft tissues around hip and knee implants.16 The evaluation and planning of hip preservation surgery in patients with hip dysplasia and femoroacetabular impingement (FAI) can be supplemented using CT (Figure 6). In addition, CT can be used in hip preservation to evaluate the patient’s femoral version and torsion. Patients with hip osteoarthritis secondary to severe hip dysplasia have small, elongated acetabula and excessive femoral anteversion, which can be determined with a preoperative CT scan.2 CT can be used in the evaluation of patients with painful THAs and equivocal radiographic findings. CT is more accurate than radiography for the evaluation of implant position and fixation. CT is used to evaluate implant position in patients with hip instability or anterior

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1: Hip and Knee

Section 1: Hip and Knee

Figure 5

Biplanar digital AP (A, C, E) and lateral (B, D, F) radiographs obtained using the EOS (EOS Imaging) low-dose radiation imaging system in weight-bearing (A, B), sitting (C, D), and squatting (E, F) positions. (Copyright Jean Yves Lazennec, MD, PhD, Paris, France.)

Figure 6

Images from a 17-year-old girl with symptomatic mild hip dysplasia whose nonsurgical treatment was unsuccessful. A and B, Preoperative AP radiographs. C, CT scan with three-dimensional reconstruction confirms the lack of anterior and lateral coverage of the femoral head. E and F, Postoperative radiographs obtained following successful periacetabular osteotomy demonstrate improved anterior and lateral coverage.

hip pain secondary to iliopsoas impingement (Figure 7). In addition, periacetabular osteolysis is more accurately determined with CT than plain radiography: CT facilitates for better detection, characterization, and quantification of bone loss around acetabular and femoral implants, as well as more accurate determination of implant fixation.17 CT scans have limited use for the evaluation of periarticular masses and fluid collections following THA. In patients whose metal-on-metal hip arthroplasties were unsuccessful, the sensitivity for diagnosising pseudotumors is only 44%.17 In this setting, the use of MRI with metal suppression or ultrasonography is recommended. Preoperative CT angiography with 3D reconstruction can help with surgical planning and awareness of abnormal vascular anatomy around the acetabulum.18 Details

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

of the periacetabular osteolysis and vascular anatomy are helpful when complex acetabular revision surgery is considered. Rotational malalignment of the femur and/or tibia can be the cause of knee pain, patella maltracking, stiffness, or instability after TKA. 2D axial CT scans have weak interobserver and intraobserver reliability in determining the rotation of the tibial and femoral implants relative to bony landmarks.19 3D reconstruction images are superior and more reliable in obtaining rotational measurements of TKA components.20 Magnetic Resonance Imaging MRI is used routinely in the evaluation of the young adult with hip pain. Metal artifact reduction sequence

© 2017 American Academy of Orthopaedic Surgeons

Chapter 1: Imaging of the Hip and Knee for Primary and Revision Arthroplasty

1: Hip and Knee

Figure 7

Images of a patient with persistent anterior groin pain following noncemented total hip arthroplasty. AP (A) and cross-table lateral (B) views demonstrate no radiographic evidence of retroversion. Axial (C) and sagittal (D) CT scans demonstrate a noncemented acetabular implant with a prominent anterior rim. Postoperative AP (E) and cross-table lateral (F) radiographs obtained following acetabular revision to treat iliopsoas impingement. (Copyright Rafael J. Sierra, MD, Mayo Clinic, Rochester, MN.)

MRI (MARS MRI) has the capability to produce high-­ resolution images of periprosthetic tissues in patients with THA implants.21 MARS MRI is commonly used for patients with metal-on-metal bearing surfaces, modular neck prostheses, or in cases for which concern exists for adverse soft-tissue reaction following THA. Magnetic resonance arthrography has been the preferred imaging test in the evaluation of FAI and associated labral pathology. However, modern 3-T MRI provides high-quality hip images, including osseous and soft-tissue structures. The labrum can be well visualized without using intra-articular contrast injection. Other advances in MRI include the use of biochemical imaging techniques such as T2 mapping, T1 rho (T1ρ) imaging, and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). These techniques were developed to detect cartilage biochemical changes, which precede structural damage or degeneration, and are used in the evaluation of patients with hip dysplasia or FAI.22 T2 mapping measures the changing interactions between water and collagen molecules of the cartilage, including the zonal variations in articular cartilage. T2 mapping values increase from deep to transitional

© 2017 American Academy of Orthopaedic Surgeons

layers in healthy articular cartilage. Cartilage damage shows an increased amount of free water and increased T2-signal intensity (Figure 8). T1ρ mapping measures low-frequency interactions between hydrogen and the macromolecules in free water. T1ρ values are correlated with the hyaline cartilage proteoglycan content. T1ρ values increase as proteoglycan content decreases in articular cartilage.22 The dGEMRIC technique uses a negatively charged gadolinium-based contrast agent to measure the glycosaminoglycan content of the cartilage. The loss of glycosaminoglycan in cartilage is an early biochemical change that precedes structural damage. The recent use of dGEMRIC imaging in the evaluation of hip cartilage has demonstrated a correlation of low dGEMRIC index and hip pain in patients with underlying hip dysplasia and FAI.23 A low dGEMRIC index is also associated with poor early outcomes in hip preservation surgery for hip dysplasia.24 MARS MRI is used in patients with THA implants for better visualization of periprosthetic bone and soft-tissue structures. MARS MRI is recommended when suspicion exists for corrosion-related metal-adverse soft-­tissue

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Section 1: Hip and Knee

1: Hip and Knee

Figure 8

Figure 9

Sagittal MRIs obtained from a 23-year-old man with femoroacetabular impingement. A, Fast spin-echo image demonstrates no cartilage defect, with visible intralabral ossification (arrow). Parametric T1ρ (B) and T2 (C) mapping demonstrate prolonged relaxation times anteriorly (blue arrows) and posterosuperiorly (white arrow). (Copyright Hollis G. Potter, MD, Hospital for Special Surgery, New York, NY, 2016.)

Coronal T1-weighted metal artifact reduction sequence MRI demonstrates large, heterogeneous pseudotumor with disruption of the abductors.

reactions in patients with metal-on-metal bearings, modular femoral necks, or in patients with larger metal cobalt-­chromium femoral heads25,26 (Figure 9). In addition, MARS MRI can help determine the presence of pseudotumors around non–metal-on-metal and modular THAs. Nuclear Imaging Traditional nuclear medicine has limited use in total joint arthroplasty because of its low specificity and high cost. Patients with stress reactions, aseptic loosening, or deep

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

prosthetic joint infections can all have positive bone scans. Despite recent advances and efforts that use bone scintigraphy to diagnose infection using labeled leukocyte scans or F-18 fluorodeoxyglucose–positron emission tomography, no role has been established for nuclear medicine in the diagnosis of prosthetic joint infection following THA or TKA.27 The new single photon emission computed tomography (SPECT)/CT arthrography is a hybrid technique that could be useful in the evaluation of the painful THA and TKA. SPECT/CT can be used in cases for which traditional tests such as radiography, serial radiographs, or fluoroscopy are inconclusive for determining THA and TKA implant loosening. Although SPECT/CT is not established in current clinical practice, one study showed promising results with sensitivity of 100%, specificity of 96.0%, positive predictive value of 92.9%, negative predictive value of 100%, and accuracy of 97.4% in the evaluation of aseptic loosening of hip and knee prostheses. 28 Ultrasonography Ultrasonography is commonly used to guide intra-­articular injections or aspirations of the hip. In clinical practice, ultrasound guided intra-articular hip injections are used to differentiate hip pain secondary to hip pathology from other sources of hip pain29 (Figure 10). Ultrasonography is also used in the evaluation and surveillance of patients with metal-on-metal THA, modular femoral neck stems, or those in whom corrosion-related metal-adverse soft-­ tissue reactions are suspected. This imaging technique is operator-dependent and the sensitivity for detecting pseudotumors varies from 69%30 to 100%31 when using MRI findings as reference.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 1: Imaging of the Hip and Knee for Primary and Revision Arthroplasty

Figure 10

Ultrasonographically guided intra-articular hip injection. A, Image demonstrates the smooth contour of the femoral head and neck. B, Image demonstrates the needle placement, inserted to the femoral neck. C, Image demonstrates the injected fluid filling the hip capsule.

Summary

Key Study Points • Weight-bearing radiographs of the hip and knee provide a more reliable determination of the joint space. • Multidetector CT is superior to plain radiography and can be used as a supplementary diagnostic test to help diagnose prearthritic conditions of the hip, periprosthetic bone loss, and implant position and fixation. • MARS MRI is used in patients in whom there is concern for corrosion-related adverse soft-tissue reaction following THA such as patients with metal-­on-metal bearing surfaces and modular neck prostheses. • MRI techniques such as T2 mapping, T1ρ imaging, and dGEMRIC have a promising role in the evaluation of prearthritic hip conditions such as FAI and adult hip dysplasia. • Traditional nuclear medicine has limited use in total joint arthroplasty because of its low specificity and high cost.

© 2017 American Academy of Orthopaedic Surgeons

1. Levine B, Fabi D, Deirmengian C: Digital templating in primary total hip and knee arthroplasty. Orthopedics 2010;33(11):797. Medline

1: Hip and Knee

Digital radiographs are the main diagnostic test in the evaluation of the adult hip and knee. Templating and preoperative planning is commonly performed in total joint arthroplasty. Advanced imaging techniques have a complimentary role to radiographs in the evaluation of multiple conditions related to hip and knee replacement issues. Narrower collimation and low- pitch adjustments in multidetector CT reduces metal artifacts and improves the image quality of bone and soft tissues around hip and knee implants. MARS MRI has the capability to produce high-resolution images of periprosthetic tissues in patients with THA implants, and is being used more frequently because of the increased awareness of corrosion related adverse effects following THA. MRI techniques such as T2 mapping, T1ρ imaging, and dGEMRIC are sophisticated techniques that evaluate the biochemical cartilage changes that precede structural damage.

Annotated References

In this report, the clinical success of digital templating with the Advanced Case Plan system in primary THA and TKA shows it was an effective means for predicting component size, thus remaining a viable option transitioning into the era of digital radiography. 2. van Bosse H, Wedge JH, Babyn P: How are dysplastic hips different? A three-dimensional CT study. Clin Orthop Relat Res 2015;473(5):1712-1723. Medline  DOI In this retrospective comparison of 3D CT scans for hip dysplasia and pelvic 3D CT scans for other reasons, dysplastic acetabuli were not deficient in a single dimension but rather globally; early detection and/or treatment are emphasized. Level of evidence: III. 3. Tamegai H, Otani T, Fujii H, Kawaguchi Y, Hayama T, Marumo K: A modified S-ROM stem in primary total hip arthroplasty for developmental dysplasia of the hip. J Arthroplasty 2013;28(10):1741-1745. Medline  DOI In this clinical study, 220 hips (Asian patients) underwent primary THA for developmental dysplasia using an S-ROM-A stem designed for Asian patients. For developmental dysplasia of the hip with femoral rotational deformity, the freely rotating modular stem provided favorable short-term outcomes and afforded morphologic and functional advantages. 4. Krych AJ, Howard JL, Trousdale RT, Cabanela ME, Berry DJ: Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia: Surgical technique. J Bone Joint Surg Am 2010;92 (suppl 1 Pt 2):176-187. Medline This study reported the results of noncemented arthroplasty with simultaneous subtrochanteric shortening osteotomy in patients with Crowe type IV developmental dysplasia of the hip. The mean Harris hip score increased from 43 to 89 points preoperatively and the complication rate was substantially higher than with primary THA in patients with degenerative arthritis.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

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Section 1: Hip and Knee

5. Abe Y, Sato S, Abe S, Masuda T, Yamada K: The impact of the leg-lengthening total hip arthroplasty on the coronal alignment of the spine. Scoliosis 2015;10(suppl 2):S4. Medline  DOI

TKA to establish recalculation using existing radiographic landmarks. Limb rotation was highly significant on measured anatomic alignment and mechanical angles.

In this study, patients were radiologically analyzed to classify coronal alignment of the spine after THA. More than 3.5° in pelvic obliquity was significantly correlated with a change in lumbar scoliosis. Compensation in lumbar scoliosis in the coronal plane after leg-lengthening THA was classified regarding pelvic obliquity and the Cobb angle.

11. Sharkey PF, Lichstein PM, Shen C, Tokarski AT, Parvizi J: Why are total knee arthroplasties failing today: Has anything changed after 10 years? J Arthroplasty 2014;29(9):1774-1778. Medline  DOI

6. Maratt JD, Esposito CI, McLawhorn AS, Jerabek SA, Padgett DE, Mayman DJ: Pelvic tilt in patients undergoing total hip arthroplasty: When does it matter? J Arthroplasty 2015;30(3):387-391. Medline  DOI

1: Hip and Knee

This study reviewed patients who underwent unilateral primary THA, most with some degree of pelvic tilt and reported that tilt-adjustment of the acetabular component position based on weight-bearing preoperative imaging will likely improve functional component position in most patients undergoing THA. 7. Melvin JS, Karthikeyan T, Cope R, Fehring TK: Early failures in total hip arthroplasty: A changing paradigm. J Arthroplasty 2014;29(6):1285-1288. Medline  DOI This study reviewed revision THAs for early failures (within 5 years of primary THA). The emergence of metallosis and aseptic loosening of metal-on-metal shells as leading causes of early failure was a concern, and early adoption of new innovations before evidence-based medicine is available was cautioned. 8. Sheth NP, Nelson CL, Springer BD, Fehring TK, Paprosky WG: Acetabular bone loss in revision total hip arthroplasty: Evaluation and management. J Am Acad Orthop Surg 2013;21(3):128-139. Medline  DOI The increase in primary THAs prompted an increase in revision THAs, which demands proper management of and appropriate radiographs in assessing acetabular bone loss. Specific classification schemes can identify bone loss patterns and guide available treatment options. 9. Sheth NP, Nelson CL, Paprosky WG: Femoral bone loss in revision total hip arthroplasty: Evaluation and management. J Am Acad Orthop Surg 2013;21(10):601-612. Medline  DOI

12. Abdel MP, Pulido L, Severson EP, Hanssen AD: Stepwise surgical correction of instability in flexion after total knee replacement. Bone Joint J 2014;96-B(12):1644-1648. Medline  DOI Identifying factors leading to instability in flexion, degree of correction determined radiologically and required at revision surgery, and clinical outcomes for revision TKA patients revealed significant improvement in mean Knee Society Score for knee and function and no instability using this stepwise approach. 13. Illés T, Somoskeöy S: The EOS™ imaging system and its uses in daily orthopaedic practice. Int Orthop 2012;36(7):1325-1331. Medline  DOI The authors of this study used the new EOS imaging system to perform routine orthopaedic diagnostics in 5,700 standard examinations since 2007: one-third in spine deformity and the rest in lower limb orthopaedic cases. This mini-review summarizes principles and integration in clinical practice. 14. Lazennec JY, Rousseau MA, Brusson A, et al: Total Hip Prostheses in Standing, Sitting and Squatting Positions: An Overview of Our 8 Years Practice Using the EOS Imaging Technology. Open Orthop J 2015;9(9):26-44. Medline This study compared 8 years of experience using low-dose EOS imaging on the first 300 THA patients with actual literature on this innovative technology, contributing to the discussion of an aging spine associated with the process of aging hips continues to evolve.

In this study, the indications for revision THA include instability, aseptic loosening, infection, and other conditions that can be associated with mild or advanced bone loss. Bone loss classification guides preoperative planning. Noncemented fixation has provided the best results, although cemented fixation is required in some cases.

15. Lazennec JY, Rousseau MA, Rangel A, et al: Pelvis and total hip arthroplasty acetabular component orientations in sitting and standing positions: Measurements reproductibility with EOS imaging system versus conventional radiographies. Orthop Traumatol Surg Res 2011;97(4):373-380. Medline  DOI

10. Radtke K, Becher C, Noll Y, Ostermeier S: Effect of limb rotation on radiographic alignment in total knee arthroplasties. Arch Orthop Trauma Surg 2010;130(4):451-457. Medline  DOI

In this prospective diagnostic study, five angular parameters characterizing pelvic tilt and acetabular cup orientation were determined using the same digital measurement imaging software based on two series of standard radiographs and EOS 2D images, and standing and sitting positions of unilateral THA patients. Level of evidence: III.

This study used synthetic femora and tibiae to evaluate the effect of limb rotation on radiographic alignment after

12

This study examined frequency and cause of failure after TKA, compared with an earlier report, and reported the most common failure mechanisms remained loosening, infection, instability, periprosthetic fracture, and arthrofibrosis, although the rates were decreased from earlier reports. Polyethylene wear was no longer the primary cause.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

© 2017 American Academy of Orthopaedic Surgeons

Chapter 1: Imaging of the Hip and Knee for Primary and Revision Arthroplasty

21. Choi SJ, Koch KM, Hargreaves BA, Stevens KJ, Gold GE: Metal artifact reduction with MAVRIC SL at 3-T MRI in patients with hip arthroplasty. AJR Am J Roentgenol 2015;204(1):140-147. Medline  DOI

This study reported that metal implants present some challenges in the performance and interpretation of CT examinations; however, metal artifacts can be minimized by decreasing the detector collimation and pitch, increasing kilovolt peak and milliampere-seconds, and using appropriate reconstruction algorithms and section thickness.

Matched 2D fast spin-echo and multiacquisition variable-resonance image combination selective (MAVRIC SL) images of 21 hips (19 with hip arthroplasty) showed MAVRIC SL can significantly reduce metal artifact on 3-T MRI compared with 2D fast spin-echo sequence and increase diagnostic confidence of 3-T MRI in THA patients.

17. Robinson E, Henckel J, Sabah S, Satchithananda K, Skinner J, Hart A: Cross-sectional imaging of metal-on-metal hip arthroplasties: Can we substitute MARS MRI with CT? Acta Orthop 2014;85(6):577-584. Medline  DOI

22. Jazrawi LM, Alaia MJ, Chang G, Fitzgerald EF, Recht MP: Advances in magnetic resonance imaging of articular cartilage. J Am Acad Orthop Surg 2011;19(7):420-429. Medline  DOI

This study reported that compared with MARS MRI in evaluating metal-on-metal hip arthroplasty patients with unexplained painful prostheses, CT was superior for detecting osteolysis adjacent to metal-on-metal hip arthroplasty, although it was unable to classify and failed to detect many pseudotumors and was unreliable in muscle atrophy assessment. Therefore, CT was an unsuitable substitute for MARS MRI.

New diagnostic tools for detecting and interpreting early cartilaginous degeneration, including biochemical-based MRI, T2 mapping, T1ρ, sodium MRI, and dGEMRIC were assessed and may eventually enhance the diagnosis and management of osteoarthritis.

18. Kawasaki Y, Egawa H, Hamada D, Takao S, Nakano S, Yasui N: Location of intrapelvic vessels around the acetabulum assessed by three-dimensional computed tomographic angiography: Prevention of vascularrelated complications in total hip arthroplasty. J Orthop Sci 2012;17(4):397-406. Medline  DOI This study reported using 3D CT angiography on subjects without hip disease to clarify the location of the external iliac, femoral, and obturator vessels at risk of vascular injury when penetrating the inner cortex of the pelvis during THA. 19. Konigsberg B, Hess R, Hartman C, Smith L, Garvin KL: Inter- and intraobserver reliability of two-dimensional CT scan for total knee arthroplasty component malrotation. Clin Orthop Relat Res 2014;472(1):212-217. Medline  DOI To determine the interobserver and intraobserver reliability and repeatability of TKA component rotation measurement using 2D CT, scans of 52 revision TKA candidates were measured. TKA component rotation variable results increased concern about CT scan diagnostics in this assessment. 20. Hirschmann MT, Konala P, Amsler F, Iranpour F, Friederich NF, Cobb JP: The position and orientation of total knee replacement components: A comparison of conventional radiographs, transverse 2D-CT slices and 3D-CT reconstruction. J Bone Joint Surg Br 2011;93(5):629-633. Medline  DOI Comparing radiographs with axial 2D and 3D reconstructed CT images, intraobserver and interobserver reliability of measurements of component position after TKA showed rotational measurements should be performed on 3D-reconstructed CT images. For poorly functioning TKA with concerns over component positioning, 3D CT is preferred.

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

16. Roth TD, Maertz NA, Parr JA, Buckwalter KA, Choplin RH: CT of the hip prosthesis: Appearance of components, fixation, and complications. Radiographics 2012;32(4):1089-1107. Medline  DOI

23. Bittersohl B, Hosalkar HS, Hesper T, Tiderius CJ, Zilkens C, Krauspe R: Advanced imaging in femoroacetabular impingement: Current state and future prospects. Front Surg 2015;2(2):34. Medline This study assessed advanced MRI techniques (dGEMRIC, T1ρ, T2/T2* mapping) to determine specific roles and the basics of each technique in FAI assessment, as well as current limitations and the future direction of biochemical imaging in early identification of articular cartilage degeneration. 24. Kim SD, Jessel R, Zurakowski D, Millis MB, Kim YJ: Anterior delayed gadolinium-enhanced MRI of cartilage values predict joint failure after periacetabular osteotomy. Clin Orthop Relat Res 2012;470(12):3332-3341. Medline  DOI In this study, the dGEMRIC index of the anterior joint compared with coronal dGEMRIC of 43 hips that underwent Bernese periacetabular osteotomy for hip dysplasia better predicted premature joint failure than did radiographic measures of hip osteoarthritis and coronal dGEMRIC index. Level of evidence: II. 25. Kwon YM, Fehring TK, Lombardi AV, Barnes CL, ­Cabanela ME, Jacobs JJ: Risk stratification algorithm for management of patients with dual modular taper total hip arthroplasty: Consensus statement of the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons and the Hip Society. J Arthroplasty 2014;29(11):2060-2064. Medline  DOI This study recommends a systematic treatment approach based on available data to optimize patient management. Specialized tests such as metal ion analysis and MARS MRI are useful in evaluating for adverse tissue reactions, although overreliance on any single investigative tool should be avoided. 26. Kwon YM, Lombardi AV, Jacobs JJ, Fehring TK, Lewis CG, Cabanela ME: Risk stratification algorithm for management of patients with metal-on-metal hip arthroplasty:

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

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Section 1: Hip and Knee

Consensus statement of the American Association of Hip and Knee Surgeons, the American Academy of Orthopaedic Surgeons, and the Hip Society. J Bone Joint Surg Am 2014;96(1):e4. Medline  DOI To prevent significant adverse biologic reactions, systematic evaluation and validation of current diagnostic tools in the early diagnosis of patients with metal-on-metal hip arthroplasty are important to further diminish wear and corrosion. 27. Workgroup Convened by the Musculoskeletal Infection Society: New definition for periprosthetic joint infection. J Arthroplasty 2011;26(8):1136-1138. Medline  DOI

1: Hip and Knee

This communication presents the diagnostic criteria and definition for periprosthetic joint infection proposed by a work group convened by the Musculoskeletal Infection Society in an effort to standardize a field that has experienced extensive variability and heterogeneity. 28. Abele JT, Swami VG, Russell G, Masson EC, Flemming JP: The accuracy of single photon emission computed tomography/computed tomography arthrography in evaluating aseptic loosening of hip and knee prostheses. J Arthroplasty 2015;30(9):1647-1651. Medline  DOI This study retrospectively evaluated nuclear medicine arthrography with hybrid SPECT/CT, in 21 hips and 17 knee patients compared with reference standards and suggests nuclear medicine arthrography with SPECT/CT may be useful in the clinical evaluation of suspected aseptic loosening. 29. Khan W, Khan M, Alradwan H, Williams R, Simunovic N, Ayeni OR: Utility of intra-articular hip injections for

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

femoroacetabular impingement: A systematic review. ­O rthop J Sports Med 2015;3(9):2325967115601030. Medline  DOI In this meta-analysis that evaluated the usefulness of intra-articular hip injection in the diagnosis/management of FAI, eight studies were categorized into diagnostic, therapeutic, and prognostic applications. Pain relief from intra-articular hip injections supported FAI diagnosis, negative response to preoperative injections may predict poor short-term surgical outcomes. 30. Siddiqui IA, Sabah SA, Satchithananda K, et al: A comparison of the diagnostic accuracy of MARS MRI and ultrasound of the painful metal-on-metal hip arthroplasty. Acta Orthop 2014;85(4):375-382. Medline  DOI In comparing MARS MRI and ultrasonography in unilateral metal-on-metal hip patients, poor agreement was found. Ultrasonography was inferior in detecting pseudotumors and muscle atrophy but superior in detecting joint effusion and tendinous pathologies. MARS MRI was preferable in preoperative planning, longitudinal comparison. Level of evidence: IV. 31. Garbuz DS, Hargreaves BA, Duncan CP, Masri BA, Wilson DR, Forster BB: The John Charnley Award: Diagnostic accuracy of MRI versus ultrasound for detecting pseudotumors in asymptomatic metal-on-metal THA. Clin Orthop Relat Res 2014;472(2):417-423. Medline  DOI This study compared ultrasonography with MRI for pseudotumor detection and assessment of growth in an asymptomatic cohort of patients with metal-on-metal THAs and reported that ultrasonography and MRI agreed in 37 of 40 patients. Ultrasonography is recommended as the initial screening tool for pseudotumors.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 2

Perioperative Assessment and Management Jay R. Lieberman, MD  Ram K. Alluri, MD

Abstract

Keywords: perioperative management; venous thromboembolism prophylaxis; anesthesia; multimodal pain management

Dr. Lieberman or an immediate family member has received royalties from DePuy Synthes and serves as a paid consultant to DePuy Synthes; has stock or stock options held in Hip Innovation Technology; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the Western Orthopaedic Association, and the American Association of Hip and Knee Surgeons. Dr. Alluri or an immediate family member has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from TriMed; has stock or stock options held in Zimmer Biomet, Stryker, and Medtronic.

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

Hip and knee arthroplasty are highly successful procedures that are associated with excellent functional outcomes for most patients. Recently, increased attention has been given to preoperative risk optimization aimed at limiting complications in patients with specific comorbidities. Venous thromboembolic prophylaxis remains of great interest because of concerns associated with the development of symptomatic pulmonary embolism and death, as well as the potential for excess anticoagulation, which may lead to bleeding. Advancements in neuraxial anesthesia and postoperative multimodal pain regimens have helped minimize postoperative complications, decrease inpatient length of stay, and improve patient satisfaction.

Introduction Hip and knee arthroplasty represent two of the largest cost centers in healthcare. With the shift of the Centers for Medicare & Medicaid Services (CMS) toward bundled payment programs for total hip arthroplasty (THA) and total knee arthroplasty (TKA), healthcare centers are attempting to minimize perioperative complications, decrease readmission rates, maximize patient outcomes, and reduce costs. The optimization of perioperative medical management, venous thromboembolism (VTE) prophylaxis, anesthesia, and postoperative pain in patients undergoing THA and TKA can have a critical effect on outcomes. Medical Management and Optimization Patients undergoing hip and knee arthroplasty are older and often have an increased burden of medical comorbidities1-3 (Table 1). Between 1991 to 2010, the number of comorbidities in this patient population doubled, the prevalence of diabetes increased from 10% to 24%, and obesity increased from 4% to 10%.2 Because the increase in comorbidities in this patient population is expected to continue, interest in preoperative medical optimization has increased. The perioperative orthopaedic surgery home model may allow for risk stratification and early identification of patients at increased risk for experiencing perioperative complications while triggering the preoperative intervention of modifiable risk factors.4 The identification of preoperative modifiable risk factors for complications depends on a careful review of each patient’s medical history, a thorough preoperative physical examination, performing basic laboratory studies, and cardiac risk stratification. Several risk prediction models have been developed on the basis of a variety of outcomes, including 30-day complications, readmission, mortality, functional outcomes, and discharge disposition. These models have resulted in the identification of several

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Section 1: Hip and Knee

Table 1

Comorbidity Prevalence in Total Hip and Total Knee Arthroplasty Patients Comorbidity

Prevalence

Hypertension

60% to 70%

Diabetes mellitus

11% to 20%

Obesity

14% to 18%

Dyslipidemia

35% to 55%

Chronic kidney disease

0.2% to 4.0%

Tobacco use

9% to 22%

Congestive heart failure

0.2% to 4.0%

1: Hip and Knee

Data from Yu S, Garvin KL, Healy WL, Pellegrini VD Jr, Iorio R: Preventing hospital readmissions and limiting the complications associated with total joint arthroplasty. J Am Acad Orthop Surg 2015;23(11):e60-e71; Gonzalez Della Valle A, Chiu YL, Ma Y, Mazumdar M, Memtsoudis SG: The metabolic syndrome in patients undergoing knee and hip arthroplasty: trends and in-hospital outcomes in the United States. J Arthroplasty 2012;27(10):17431749; and Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR: Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010. JAMA 2012;308(12):1227-1236.

important risk factors for postoperative complications. Diabetes Studies have consistently identified diabetes as a risk factor for postoperative complications, and it is included in most risk-stratification algorithms. The preoperative screening of patients with hyperglycemia by checking hemoglobin A1c (HbA1c) has been an area of increased interest. HbA1c levels greater than 6.7 have been associated with an increased risk of postoperative wound complications.5 However, the target HbA1c level for ideal preoperative optimization remains unclear, and not all patients may be able to achieve a target level.6 Strict adherence to a certain target level may needlessly delay surgery. Additionally, HbA1c may not be the best surrogate for quantifying the severity of a patient’s diabetes, as it is a measure of chronic glycemic control, and acute glycemic control—measured via fasting glucose levels—may also be considered.7 Obesity Obesity has been consistently identified as a risk factor for postoperative complications after THA and TKA. Specifically, obesity increases the risk of acute kidney failure, cardiovascular complications, and postoperative infection.8 One study’s findings demonstrated an increase of greater than 100% in postoperative infection rates in a comparison of patients who had a normal

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

body mass index (BMI) with patients who were morbidly obese.9 There is no absolute BMI at which patients’ risk of the development of postoperative complications significantly increases; however, many studies stratify patients as having a BMI greater or less than 40 kg/m2. Additionally, the exact amount or percentage of weight loss needed preoperatively to improve postoperative outcomes remains unclear, and a weight loss greater than 5% may be needed to decrease the risk of postoperative complications.10 Although bariatric surgery has been proved to decrease BMI, the timing of bariatric surgery before arthroplasty and its effect on postoperative arthroplasty outcomes remains unclear and requires further investigation. Smoking Tobacco use is thought to be one of the most important risk factors contributing to postoperative complications, particularly wound complications, which are nearly doubled in active smokers compared with nonsmokers.11 Previous studies have demonstrated that a smoking cessation program started 6 to 8 weeks before surgery can decrease postoperative complications; however, monitoring compliance remains a challenge.12 Nicotine screening tests assessing the blood level of cotinine allow for the identification of noncompliance with cessation, potentially decreasing postoperative complication rates. Cardiovascular Disease Cardiovascular complications represent one of the most common systemic adverse events after arthroplasty, and these complications can result in death. Major risk factors for postoperative cardiovascular complications include preoperative cardiovascular disease and older age.13,14 Patients with cardiac stents present a challenging situation for the arthroplasty surgeon, and different stent types mandate different forms of management. The current recommendation is for elective noncardiac surgery to be delayed in patients in whom dual antiplatelet therapy will need to be discontinued within 30 days after bare-metal stent implantation or 12 months after drug-eluting stent implantation.15 No evidence-based guidelines exist for antiplatelet therapy cessation and total joint arthroplasty. However, if the surgeon and cardiologist elect to discontinue clopidogrel, it is recommended that aspirin be continued if possible and clopidogrel be restarted as soon as possible after surgery. Stopping clopidogrel 7 days before surgery may decrease postoperative bleeding-related events and decrease the need for perioperative transfusion from 31.8% to 7.7% without increasing perioperative adverse cardiac events.16

© 2017 American Academy of Orthopaedic Surgeons

Chapter 2: Perioperative Assessment and Management

Blood Transfusion Perioperative blood transfusion has been previously associated with significant postoperative complications, including sepsis, VTE, readmissions, and mortality.17 Multiple randomized controlled trials have demonstrated the capability of tranexamic acid to decrease intraoperative and postoperative blood loss, thereby minimizing postoperative transfusion rates and decreasing postoperative complications.18

Methicillin-Resistant Staphylococcus aureus Methicillin-resistant Staphylococcus aureus (MRSA) colonization, particularly in the nares, is thought to be a risk factor for postoperative surgical site infections. Some surgeons elect to screen patients for MRSA colonization and, in the setting of a positive test result, decolonization is attempted with various regimens. Both mupirocin ointment and chlorhexidine wipes have demonstrated efficacy in decreasing surgical site infections in some studies, 21,22 but the overall efficacy of these regimens has not been definitively demonstrated.23 Venous Thromboembolism Prophylaxis VTE is one the most common perioperative complications after TKA and THA, and orthopaedic surgeons are highly interested in VTE prophylaxis because it can prevent significant postoperative complications, including death. The American College of Chest Physicians (ACCP) first established VTE prophylaxis guidelines in 1986 and have updated them approximately every 3 years. Initially, the orthopaedic community had significant concerns regarding these guidelines because of an increased emphasis on efficacy of a prophylaxis regimen and a limited focus on bleeding. However, the most recent guidelines, published in 2012, recommended a variety of new regimens, including aspirin and portable mechanical compression24-27 (Table 2). The American Academy of Orthopaedic Surgeons (AAOS) guidelines26 do not recommend a specific regimen

© 2017 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

1: Hip and Knee

Renal Disease Patients undergoing THA and TKA are at 10 to 20 times greater risk of experiencing complications when already receiving dialysis.19 Evidence suggests patients with endstage renal disease receiving dialysis may have improved postoperative outcomes if they elect to undergo renal transplantation before undergoing total joint arthroplasty.20 In patients undergoing THA or TKA, the comparative risk of transient septicemia during dialysis versus the risk of immunosuppression after kidney transplantation needs to be fully considered.

or duration for VTE prophylaxis after THA and TKA (Table 2). The ACCP recommends one of the following agents: vitamin K antagonists (such as warfarin), low-­molecular– weight heparins (LMWHs; such as enoxaparin), aspirin, factor Xa inhibitors (such as apixaban and rivaroxaban), pentasaccharides (such as fondaparinux), direct thrombin inhibitors (such as dabigatran), and mobile portable compression devices (Table 3). ACCP guidelines recommend 10 to 14 days of VTE prophylaxis after THA and TKA, with a potential extension for up to 35 days.24 Recently, interest increased regarding the use of antiplatelet agents and mobile mechanical compression devices for VTE prophylaxis as surgeons continue to investigate the ideal balance between efficacy and safety. The ideal anticoagulation regimen for each patient needs to be based on risk stratification, attempting to minimize complications caused by inadequate or excessive anticoagulation. Increased interest in aspirin as an agent of VTE prophylaxis was largely driven by the Pulmonary Embolism Prevention (PEP) trial. This international study demonstrated a significant difference between aspirin and placebo, without an increase in bleeding complications, with respect to the rate of VTE in patients with a hip fracture treated using arthroplasty.28 However, no differences were noted in the VTE rates between the aspirin and placebo groups in THA patients. A retrospective registry study demonstrated similar VTE complication rates when aspirin was compared with LMWH, 29 but mortality was higher in patients receiving aspirin prophylaxis. In a randomized trial of extended-duration VTE prophylaxis efficacy, researchers noted that aspirin and dalteparin were associated with similar rates of VTE events.30 However, the findings of a prospective study in which the investigators compared warfarin with aspirin after THA and TKA demonstrated increased rates of VTE complications in patients receiving aspirin.31 Aspirin remains an attractive agent for VTE prophylaxis after THA and TKA given its oral administration, high rate of patient compliance, and cost-effectiveness. Aspirin is likely not as powerful an anticoagulant as other available chemoprophylaxis agents but bleeding rates seem to be lower. Appropriately powered randomized trials are needed to determine its true efficacy and safety. Interest has also increased in mobile pneumatic compression devices for VTE prophylaxis following THA and TKA because of shorter hospital lengths of stay. The findings of studies from 2010 and 2014 in which investigators compared current pharmacologic protocols with the use of a mobile compression device suggested similar efficacy between the two modalities.32,33 However, in these studies, 60% of patients using mobile compression

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Table 2

Prevention of Venous Thromboembolic Disease after THA and TKA: Select Guidelines Grade of Recommendation

American College of Chest Physicians Recommendations

1: Hip and Knee

In patients undergoing THA or TKA, one of the following agents should be used for a minimum of 10 to 14 days rather than no venothrombotic prophylaxis: LMWH

1B

Fondaparinux

1B

Apixaban

1B

Dabigatran

1B

Rivaroxaban

1B

Low-dose unfractionated heparin

1B

Adjusted-dose vitamin K antagonist

1B

Aspirin

1B

IPCD

1C

In patients undergoing THA or TKA, regardless of the use of an IPCD or length of treatment, LMWH should be used in preference to other alternative agents: Fondaparinux

2B

Apixaban

2B

Dabigatran

2B

Rivaroxaban

2B

Low-dose unfractionated heparin

2B

Adjusted-dose vitamin K antagonist

2C

Aspirin

2C

For patients undergoing THA or TKA, thromboprophylaxis should be extended in the outpatient period for up to 35 days following surgery rather than for only 10 to 14 days.

2B

In patients undergoing THA or TKA, dual prophylaxis with an antithrombotic agent and an IPCD during the hospital stay is recommended.

2C

Strength of Recommendation

American Academy of Orthopaedic Surgeons Recommendations The workgroup suggests the use of pharmacologic agents, mechanical compressive devices, or both for the prevention of venous thromboembolism in patients undergoing elective THA or TKA who are not at elevated risk beyond that of the surgery itself of experiencing venous thromboembolism or bleeding.

Moderate

The workgroup cannot recommend for or against a specific prophylactic regimen in these patients, as current evidence is unclear about which strategy or strategies is or are optimal or suboptimal.

Consensus

In the absence of reliable evidence regarding the duration of prophylactic strategies, it is the opinion of the panel that patients and physicians should discuss the duration of prophylaxis.

Consensus

In the absence of reliable evidence, it is the opinion of the panel that patients should undergo early mobilization following elective THA or TKA.

Consensus

The use of neuraxial anesthesia for patients undergoing THA or TKA is recommended to help limit blood loss, even though evidence suggests that neuraxial anesthesia does not affect the occurrence of venous thromboembolic disease.

Moderate

ICPD = intermittent pneumatic compression device, LMWH = low-molecular–weight heparin, THA = total hip arthroplasty, TKA = total knee arthroplasty. Data from Falck-Ytter Y, Francis CW, Johanson NA, et al: Prevention of VTE in orthopaedic surgery patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141(2 suppl):e278S-e325S; Lieberman JR, Pensak MJ: Prevention of venous thromboembolic disease after total hip and knee arthroplasty. J Bone Joint Surg Am 2013;95(19):1801-1811; Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty. 2011; available at http://www.aaos.org/research/guidelines/VTE/VTE_guideline.asp; Lieberman JR: The new AAOS clinical practice guidelines on venous thromboembolic prophylaxis: How to adapt them to your practice. J Am Acad Orthop Surg 2011;19(12):717-721.

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© 2017 American Academy of Orthopaedic Surgeons

Chapter 2: Perioperative Assessment and Management

Table 3

Common Venous Thromboembolism Prophylaxis Dosing Regimens Common Dosing or Therapeutic Level

Warfarin

International normalized ratio, 2.0

Enoxaparin

30 mg subcutaneously two times per day or 40 mg subcutaneously per day

Apixaban

2.5 mg orally two times per day

Rivaroxaban

10 mg orally per day

Fondaparinux

2.5 mg subcutaneously per day

Dabigatran

150 mg orally two times per day

Aspirin

325 mg orally one or two times per day

also took aspirin.33 The aforementioned results led to the ACCP’s recommending (grade IC) mobile pneumatic compression devices as a stand-alone measure for VTE prophylaxis after THA and TKA only if worn for at least 18 hours per day.24 Appropriately powered trials are needed to define the true efficacy of mobile compression, and concerns related to the cost of these devices also exist. Anesthesia Options THA and TKA are commonly performed under neuraxial anesthesia. Neuraxial, or regional, anesthesia has been hypothesized to lower postoperative complications because of decreased sympathetic activation and inflammation, thus decreasing the overall surgical stress response when compared with general anesthesia. However, robust evidence demonstrating the purported benefits of neuraxial anesthesia is lacking, and the optimal anesthetic technique for THA and TKA has not yet been determined. Several studies since 2010 have demonstrated potential clinical benefits of neuraxial anesthesia versus general anesthesia. The findings of a retrospective registry study demonstrated decreased mortality in THA patients receiving spinal versus general anesthesia;34 however, a similar study did not demonstrate decreased mortality in TKA patients.35 Several retrospective database studies have shown neuraxial anesthesia to be associated with decreased surgical time, surgical site infections, postoperative cardiovascular and pulmonary complications, transfusion rates, and overall length of inpatient stay after THA and TKA.36,37 Prospective studies comparing general versus neuraxial anesthesia in patients undergoing THA and TKA are sparse, but their findings have demonstrated

© 2017 American Academy of Orthopaedic Surgeons

Pain Management The primary goal of postoperative pain management is to reduce pain, thereby improving early postoperative mobilization, patient-perceived outcomes, and length of inpatient hospital stay. These regimens use both pharmacologic and nonpharmacologic interventions that target several different regions of the pain pathway, thus decreasing the total required dose of each drug. Many of these regimens involve the use of medications with different durations of action and are administered on a scheduled basis.

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Pharmacologic Agent

more favorable recovery profiles associated with general anesthesia than with regional anesthesia.38,39 However, these prospective studies assessed primarily postoperative pain, nausea, and length of stay.38,39 Authors of a systematic review comparing both anesthetic types in THA and TKA patients concluded there is limited evidence suggesting a potential benefit of neuraxial anesthesia with respect to perioperative outcomes.40 However, these studies did not assess the combination of regional anesthesia with the use of preemptive analgesia, regional blocks, or both in TKA that are currently in use.

Oral Medications As multimodal pain management regimens have evolved, increased focus has been placed on decreasing postoperative opioid consumption. Many prospective randomized studies assessing the efficacy of multimodal regimens have used opioid consumption as a primary outcome. A major reason for the continued focus on decreasing postarthroplasty opioid intake is that opioid-related adverse effects (sedation, nausea, vomiting, urinary retention) can have a negative effect on the rehabilitation process, prolong inpatient stays, and increase healthcare resource consumption. The findings of one study demonstrated that more than 50% of postarthroplasty complications were caused by opioid-related adverse drug events.41 Although many of these multimodal pain regimens have decreased opioid consumption during inpatient hospitalization, orthopaedic surgeons still rely on opioid and nonopioid-based oral pain medications to control postdischarge pain. The use of oral pain medications may start before surgery. The use of NSAIDs for preemptive analgesia, particularly selective cyclooxygenase-2 (COX-2) inhibitors, has demonstrated improved postoperative pain scores, decreased opioid consumption, and greater active range of motion (ROM) without increasing perioperative bleeding.42,43 The use of pregabalin preoperatively has also been shown to decrease opioid consumption, decrease overall pain scores, and improve ROM outcomes.44,45

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Section 1: Hip and Knee

1: Hip and Knee

Periarticular Injections Periarticular injections (PAIs) are often a concoction of several medications, including local anesthetics, opioids, NSAIDs, and corticosteroids. These mixtures are injected into the capsule and periarticular tissue during THA and TKA. Comparative studies are difficult to analyze, given the variability of when and where these injections are placed and the different drugs used in these injection cocktails. Several well-designed level I studies have compared the efficacy of PAIs with that of femoral nerve blocks in TKA patients and have demonstrated that PAIs had equivalent analgesic outcomes.46,47 Either a peripheral nerve block or a PAI can be used for postoperative pain control in these patients, but PAIs may be safer, cheaper, and easier to perform. The literature assessing the efficacy of PAIs in THA is not as robust as that in the TKA population. In THA, PAIs demonstrated improved postoperative pain control, decreased opioid consumption, and better early functional outcomes when compared with placebo in one study,48 although another study failed to demonstrate a similar result.49 The drugs used in the injection cocktail may influence these results. Peripheral Nerve Blocks Both single and continuous peripheral nerve blockades have demonstrated improvement in postoperative pain, length of stay, and patient satisfaction after THA and TKA. A potential disadvantage of these peripheral nerve blocks is the resultant muscular weakness, which potentially increases the risk of postoperative falls. The integration of ultrasonography to facilitate localization of the desired nerve or plexus has enhanced the safety of these blockades. Common peripheral nerve blocks executed after THA include lumbar plexus blocks, psoas compartment blocks, femoral nerve blocks, and sciatic nerve blocks. Patients undergoing TKA may receive a femoral nerve, adductor canal, or sciatic nerve block, or a combination thereof. Continuous nerve blocks have demonstrated improved pain control with postoperative motion and less opioid consumption versus single-injection blocks.50 Increased

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

interest in the adductor canal block has developed with the underlying thought that isolated blockade of sensory nerves with an adductor canal block may minimize the muscular weakness associated with femoral nerve blocks. Findings of subsequent studies have demonstrated adductor canal blocks to result in postoperative quadriceps strength and ambulation outcomes superior to those seen with femoral nerve blocks while providing similar levels of pain control.51,52 Some surgeons combine a PAI with an adductor canal block, but the efficacy of this regimen needs to be determined in randomized trials. The use of a sciatic nerve block after TKA, although controversial, is thought to help decrease posterior knee pain.53 Summary THA and TKA continue to remain some of the most successful surgical procedures, resulting in high patient satisfaction. The burden of comorbidities in patients electing to undergo these procedures is likely to continue rising, and therefore preoperative optimization is of paramount importance. Recent research has helped identify patients at risk for postoperative complications, but further research is needed to identify the optimal strategy to best modify these factors and their effect on outcomes. VTE continues to be one of the most common complications after THA and TKA, and recent guidelines do not specify a single agent or regimen for postoperative prophylaxis. Risk stratification is the key in selecting an appropriate VTE prophylaxis regimen, but the critical factors associated with a pulmonary embolism need to be determined. Furthermore, appropriately powered randomized trials with well-defined parameters for VTE complications are needed to directly assess the efficacy of various agents. The choice of general versus neuraxial anesthesia remains important, and neuraxial anesthesia may offer clinically relevant advantages, but adequately powered randomized trials assessing these clinical outcomes are still needed. Multimodal pain regimens after THA and TKA have resulted in decreased postoperative opioid consumption, fewer postoperative complications, shorter inpatient lengths of stay, and higher patient satisfaction.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 2: Perioperative Assessment and Management

Key Study Points

Annotated References 1. Gonzalez Della Valle A, Chiu YL, Ma Y, Mazumdar M, Memtsoudis SG: The metabolic syndrome in patients undergoing knee and hip arthroplasty: Trends and in-hospital outcomes in the United States. J Arthroplasty 2012;27(10):1743-1749.e1. Medline  DOI The authors of this database study evaluated the effect of metabolic syndrome on perioperative outcomes in patients undergoing TKA or THA. The prevalence of metabolic syndrome from 2000 to 2008 progressively increased and was a risk factor for major perioperative complications. Level of evidence: III. 2. Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR: Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010. JAMA 2012;308(12):1227-1236. Medline  DOI The authors of this study identified patients who underwent TKA between 1991 and 2010 by using Medicare data files. Significant findings included an increase of 162% in primary TKA volume during this period and a doubling in the number of comorbidities in this patient population. In primary TKA, length of stay decreased from 7.9 days to 3.5 days, but 30-day readmission rates increased from 4.2% to 5.0%. Level of evidence: III. 3. Yu S, Garvin KL, Healy WL, Pellegrini VD Jr, Iorio R: Preventing hospital readmissions and limiting the complications associated with total joint arthroplasty. J Am Acad Orthop Surg 2015;23(11):e60-e71. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

4. Boraiah S, Joo L, Inneh IA, et al: Management of modifiable risk factors prior to primary hip and knee arthroplasty: A readmission risk assessment tool. J Bone Joint Surg Am 2015;97(23):1921-1928. Medline  DOI The authors of this study developed the Readmission Risk Assessment Tool (RRAT) scoring system, which demonstrated a significant association with readmission. The most common risk factors for readmission included diabetes (odds ratio [OR], 2.96), history of VTE disease (OR, 8.13), and smoking (OR, 1.66).

1: Hip and Knee

• As the burden of medical comorbidities in patients undergoing THA and TKA continues to increase, preoperative optimization of modifiable risk factors is critical in achieving excellent postoperative outcomes. • Neuraxial versus general anesthesia potentially limits postoperative complications after THA and TKA, but the ideal anesthetic technique needs to be determined. • VTE prophylaxis after THA and TKA is of paramount importance. The ideal prophylaxis regimen and duration remain undetermined and are dependent on risk stratification of each patient. A validated risk stratification system needs to be developed. • Multimodal postoperative pain regimens are important in achieving high levels of patient satisfaction, and early mobilization, and in minimizing opioid-­ related adverse effects. Preemptive analgesia combined with periarticular injections are becoming increasingly popular and may be used in addition to or in lieu of peripheral nerve blocks.

This review article emphasizes the need to minimize perioperative complications and readmissions in the setting of increased arthroplasty prevalence. Specifically discussed risk factors for perioperative complications include morbid obesity, diabetes, nutritional deficiencies, tobacco use, thromboembolic disease, cardiovascular disease, neurocognitive dysfunction, psychological or behavioral problems, physical deconditioning, and S aureus colonization. Level of evidence: V.

5. Stryker LS, Abdel MP, Morrey ME, Morrow MM, Kor DJ, Morrey BF: Elevated postoperative blood glucose and preoperative hemoglobin A1c are associated with increased wound complications following total joint arthroplasty. J Bone Joint Surg Am 2013;95(9):808-814, S1-S2. Medline  DOI The authors of this study identified patients with elevated preoperative hemoglobin A1 c (HbA1c) and postoperative blood glucose levels who also had postoperative wound complications. The OR was 3.75 for developing a wound complication in patients with postoperative mean glucose values greater than 200 mg/dL, and the OR was 9.0 in patients with preoperative HbA1c values greater than 6.7%. Level of evidence: III. 6. Giori NJ, Ellerbe LS, Bowe T, Gupta S, Harris AH: Many diabetic total joint arthroplasty candidates are unable to achieve a preoperative hemoglobin A1c goal of 7% or less. J Bone Joint Surg Am 2014;96(6):500-504. Medline  DOI The authors of this study identified patients with preoperative hemoglobin A1c (HbA1c) levels greater than 7%. Of the patients identified, 60% were able to achieve HbA1c levels less than 7% after a mean 232 days. Typically, patients with higher HbA1c values were less likely to achieve levels less than 7%. Certain patients may not be able to achieve HbA1c levels below 7% and perhaps surgery should not be delayed in these patients. Level of evidence: IV. 7. Hwang JS, Kim SJ, Bamne AB, Na YG, Kim TK: Do glycemic markers predict occurrence of complications after total knee arthroplasty in patients with diabetes? Clin Orthop Relat Res 2015;473(5):1726-1731. Medline  DOI In this study, the authors attempted to identify a correlation between postoperative complications after TKA in patients with diabetes and the following glycemic markers: preoperative fasting blood glucose, postprandial glucose, hemoglobin HbA1c, and random postoperative glucose levels. Only hemoglobin HbA1c values greater than 8 or fasting blood glucose levels greater than 200 mg/dL were associated with superficial surgical site infections. Level of evidence: III.

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Section 1: Hip and Knee

8. Ward DT, Metz LN, Horst PK, Kim HT, Kuo AC: Complications of morbid obesity in total joint arthroplasty: Risk stratification based on BMI. J Arthroplasty 2015;30 (9suppl):42-46. Medline  DOI The authors of this database review identified patients undergoing THA or TKA and stratified these patients according to BMI. Increasing BMI led to an increase in postoperative complications (15.2% versus 17.4%). Specific complications found to have increased incidence included acute kidney injury (1.9% versus 3.9%), cardiac arrest (0.2% versus 0.6%), revision surgery (2.4% versus 3.4%), and superficial infection (0.8% versus 1.7%). Level of evidence: III.

1: Hip and Knee

9. Jameson SS, Mason JM, Baker PN, Elson DW, Deehan DJ, Reed MR: The impact of body mass index on patient reported outcome measures (PROMs) and complications following primary hip arthroplasty. J Arthroplasty 2014;29(10):1889-1898. Medline  DOI The authors of this registry review identified patients undergoing THA. All patients, irrespective of BMI, demonstrated large improvements in postoperative outcomes, but patients with increasing BMI demonstrated marginally smaller improvement and higher rates of bleeding complications (3.7% versus 4.4%), wound complications (7.2% versus 15.0%), revision surgery (1.6% versus 4.4%) and readmission (6.2 versus 11.2%). Level of evidence: III.

The authors of this study identified patients who died as a result of myocardial infarction within 30 days of undergoing THA or TKA. Preoperative anemia was not identified as a risk factor for death or nonfatal myocardial infarction. The most important risk factors identified included cardiovascular and pulmonary disease. Level of evidence: III. 14. Belmont PJ Jr, Goodman GP, Kusnezov NA, et al: Postoperative myocardial infarction and cardiac arrest following primary total knee and hip arthroplasty: Rates, risk factors, and time of occurrence. J Bone Joint Surg Am 2014;96(24):2025-2031. Medline  DOI The authors of this study identified all patients with cardiac complications within 30 days of THA or TKA in a national data set. The cardiac complication rate was 0.33%. The most significant risk factors for cardiac complications for the individual TKA and THA groups included age older than 80 years (OR, 28.0 and 3.7), hypertension requiring medication (OR, 4.7 and 2.6), and a history of cardiac disease (OR, 4.5 and 2.8). The average cardiac complication occurred within 7 days of the index procedure. Level of evidence: III.

10. Inacio MC, Kritz-Silverstein D, Raman R, et al: The impact of pre-operative weight loss on incidence of surgical site infection and readmission rates after total joint arthroplasty. J Arthroplasty 2014;29(3):458-464.e1. Medline  DOI

15. Fleisher LA, Fleischmann KE, Auerbach AD, et al: 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation 2014;130(24):2215-2245. Medline  DOI

The authors of this database study identified patients undergoing THA or TKA. They calculated changes in patients’ preoperative weight and stratified patients according to weight loss (>5% weight loss, no change, and >5% weight gain): 80% of patients maintained the same weight. The risk of surgical site infection and readmission was not significantly different among the three groups. Level of evidence: III.

This is an executive summary of the American College of Cardiology and American Heart Association 2014 guidelines on perioperative cardiovascular management for patients undergoing noncardiac surgery. The guidelines recommend not performing elective surgery in patients in whom dual antiplatelet therapy will need to be discontinued within 30 days after bare-metal stent implantation and 12 months after drug-eluting stent implantation.

11. Duchman KR, Gao Y, Pugely AJ, Martin CT, Noiseux NO, Callaghan JJ: The effect of smoking on short-term complications following total hip and knee arthroplasty. J Bone Joint Surg Am 2015;97(13):1049-1058. Medline  DOI

16. Jacob AK, Hurley SP, Loughran SM, Wetsch TM, Trousdale RT: Continuing clopidogrel during elective total hip and knee arthroplasty: Assessment of bleeding risk and adverse outcomes. J Arthroplasty 2014;29(2):325-328. Medline  DOI

The authors identified patients who underwent THA and TKA according to smoking status. Current smokers had a higher rate of wound complications compared with nonsmokers (1.8% versus 1.1%). Former smokers had a higher rate of total complications compared with current smokers (6.9% versus 5.9%). Increased pack-years of smoking history resulted in increased total complication risk. Level of evidence: III. 12. Møller AM, Pedersen T, Villebro N, Munksgaard A: Effect of smoking on early complications after elective orthopaedic surgery. J Bone Joint Surg Br 2003;85(2):178-181. Medline  DOI 13. Mantilla CB, Wass CT, Goodrich KA, et al: Risk for perioperative myocardial infarction and mortality in patients

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undergoing hip or knee arthroplasty: The role of anemia. Transfusion 2011;51(1):82-91. Medline  DOI

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

The authors of this registry study identified patients undergoing THA or TKA and analyzed the relationship between perioperative use or discontinuation of clopidogrel and intraoperative blood loss and postoperative complications. Patients who continued clopidogrel were more likely to receive a transfusion within 24 hours after surgery (31.8% versus 7.7%). The incidence of adverse cardiac effects within 30 days was not different between the two groups. Level of evidence: III. 17. Browne JA, Adib F, Brown TE, Novicoff WM: Transfusion rates are increasing following total hip arthroplasty: Risk factors and outcomes. J Arthroplasty 2013;28(8suppl):34-37. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

Chapter 2: Perioperative Assessment and Management

The authors of this database study assessed transfusion trends in patients undergoing THA. From 2005 to 2008, transfusion rates increased from 18% to 21%. The most significant predictors of need for transfusion were age older than 85 years (OR, 2.9) and a high Charlson Comorbidity Index score (OR, 2.2). Patients receiving transfusions had increased in-hospital mortality rates, longer hospital lengths of stay, and higher total charges. Level of evidence: III. 18. Aguilera X, Martinez-Zapata MJ, Bosch A, et al: Efficacy and safety of fibrin glue and tranexamic acid to prevent postoperative blood loss in total knee arthroplasty: A randomized controlled clinical trial. J Bone Joint Surg Am 2013;95(22):2001-2007. Medline  DOI

19. Ponnusamy KE, Jain A, Thakkar SC, Sterling RS, Skolasky RL, Khanuja HS: Inpatient mortality and morbidity for dialysis-dependent patients undergoing primary total hip or knee arthroplasty. J Bone Joint Surg Am 2015;97(16):1326-1332. Medline  DOI The authors of this study identified dialysis-dependent patients who underwent THA or TKA and compared them with not receiving dialysis. Dialysis-dependent patients had higher inpatient mortality rates after THA (1.9% versus 0.13%) and overall complication rates (10.0% versus 5.0%); dialysis-dependent patients also had higher inpatient mortality rates after TKA (0.92% versus 0.10%) and overall complications rates (12.5% versus 1.9%). Level of evidence: III. 20. Cavanaugh PK, Chen AF, Rasouli MR, Post ZD, Orozco FR, Ong AC: Complications and mortality in chronic renal failure patients undergoing total joint arthroplasty: A comparison between dialysis and renal transplant patients. J Arthroplasty 2016;31(2):465-472. Medline  DOI This database study compared patients undergoing THA or TKA with chronic kidney disease or end-stage renal disease with patients with normal renal function. A subanalysis compared patients with end-stage renal disease on dialysis to those following kidney transplantation. Patients receiving dialysis had higher rates of surgical site infections (OR, 2.9), transfusion (OR, 2.3), and in-hospital mortality (OR, 6.3) compared with patients who underwent kidney transplantation. The authors concluded that renal transplantation before total joint arthroplasty should be considered. Level of evidence: III. 21. Schweizer ML, Chiang HY, Septimus E, et al: Association of a bundled intervention with surgical site infections among patients undergoing cardiac, hip, or knee surgery. JAMA 2015;313(21):2162-2171. Medline  DOI Researchers assessed the rates of surgical site infection in patients undergoing cardiac procedures requiring a median sternotomy and in patients undergoing hip or

© 2017 American Academy of Orthopaedic Surgeons

22. Kapadia BH, Johnson AJ, Daley JA, Issa K, Mont MA: Pre-admission cutaneous chlorhexidine preparation reduces surgical site infections in total hip arthroplasty. J Arthroplasty 2013;28(3):490-493. Medline  DOI Investigators identified patients who participated in a 2% chlorhexidine gluconate surgical preparation protocol with two applications (the night before and the morning of surgery). A lower incidence of deep incisional and periprosthetic infections occurred in the chlorhexidine group (0.5% versus 1.7%). Level of evidence: III.

1: Hip and Knee

The authors assessed the efficacy of fibrin glue and tranexamic acid in decreasing total blood loss and need for blood transfusions postoperatively. They divided patients into four treatment groups (1, fibrin; 2, fibrinogen and thrombin; 3, intravenous tranexamic acid; 4, no treatment [control]). The tranexamic acid group had significantly lower blood loss compared with the control group and had the lowest blood transfusion rate. Level of evidence: I.

knee arthroplasty. Patients with a positive preoperative nares screen for MRSA or methicillin-susceptible S aureus were instructed to apply mupirocin intranasally twice daily and bathe daily in chlorhexidine gluconate for up to 5 days before surgery. Compared with the preintervention period, the rate ratio for complex surgical site infections in the postintervention period was 0.48 for hip and knee arthroplasty. Level of evidence: III.

23. Baratz MD, Hallmark R, Odum SM, Springer BD: Twenty percent of patients may remain colonized with methicillin-resistant Staphylococcus aureus despite a decolonization protocol in patients undergoing elective total joint arthroplasty. Clin Orthop Relat Res 2015;473(7):22832290. Medline  DOI Researchers identified patients who had positive results for MRSA or methicillin-sensitive S aureus after nares screening. These patients were treated with intranasal mupirocin ointment twice daily and daily skin cleansing with 4% chlorhexidine soap for 5 days before surgery. Patients’ nares were rescreened on the day of surgery for methicillin-sensitive S aureus or MRSA: 22% of patients remained colonized after the protocol. The test group demonstrated no difference in infection risk compared with the control group. Level of evidence: III. 24. Falck-Ytter Y, Francis CW, Johanson NA, et al; American College of Chest Physicians: Prevention of VTE in orthopedic surgery patients: Antithrombotic therapy and prevention of thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012;141(2 suppl):e278S-e325S. Medline  DOI This is the American College of Chest Physicians’ most recent recommendation for VTE prophylaxis for patients undergoing orthopaedic surgery, including total THA and TKA. The major changes in the ninth edition included the addition of aspirin for VTE prophylaxis and an increased emphasis on safety of VTE prophylaxis (prior guidelines emphasized efficacy). 25. Lieberman JR, Pensak MJ: Prevention of venous thromboembolic disease after total hip and knee arthroplasty. J Bone Joint Surg Am 2013;95(19):1801-1811. Medline  DOI This is a review article discussing the most recent AAOS and ACCP guidelines for VTE prophylaxis after total joint arthroplasty. The need for balancing the safety and efficacy of VTE prophylaxis in each individual patient was emphasized. Further randomized trials are still needed to select the optimal prophylaxis regimen.

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Section 1: Hip and Knee

26. American Academy of Orthopaedic Surgeons: Clinical Practice Guidelines on Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2011. Available at: http://www. aaos.org/research/guidelines/VTE/VTE_guideline.asp This is the most recent AAOS clinical practice guideline for VTE prophylaxis after THA and TKA. The AAOS guideline panel was unable to make a specific recommendation regarding type and duration of VTE prophylaxis. 27. Lieberman JR: The new AAOS clinical practice guidelines on venous thromboembolic prophylaxis: How to adapt them to your practice. J Am Acad Orthop Surg 2011;19(12):717-721. Medline  DOI

1: Hip and Knee

This commentary reviews the 2011 AAOS VTE prophylaxis guideline for THA and TKA. The author commends the AAOS workgroup for focusing on the importance of symptomatic VTE events and bleeding complications when selecting a prophylaxis regimen. However, no specific regimen or duration of prophylaxis was recommended. 28. Pulmonary Embolism Prevention (PEP) trial Collaborative Group: Prevention of pulmonary embolism and deep vein thrombosis with low dose aspirin: Pulmonary Embolism Prevention (PEP) trial. Lancet 2000;355(9212): 1295-1302. Medline  DOI 29. Jameson SS, Charman SC, Gregg PJ, Reed MR, van der Meulen JH: The effect of aspirin and low-molecular-weight heparin on venous thromboembolism after hip replacement: A non-randomised comparison from information in the National Joint Registry. J Bone Joint Surg Br 2011;93(11):1465-1470. Medline  DOI

32. Colwell CW Jr, Froimson MI, Anseth SD, et al: A mobile compression device for thrombosis prevention in hip and knee arthroplasty. J Bone Joint Surg Am 2014;96(3): 177-183. Medline  DOI The authors of this study analyzed patients who underwent hip or knee arthroplasty and received mobile compression VTE prophylaxis with or without the use of aspirin. The VTE rate was 0.92%, the therapy was considered noninferior to warfarin, enoxaparin, rivaroxaban, and dabigatran therapy. Level of evidence: II. 33. Colwell CW Jr, Froimson MI, Mont MA, et al: Thrombosis prevention after total hip arthroplasty: A prospective, randomized trial comparing a mobile compression device with low-molecular-weight heparin. J Bone Joint Surg Am 2010;92(3):527-535. Medline  DOI Investigators randomly assigned patients undergoing THA to receive VTE prophylaxis with a mobile compression device or low-molecular–weight heparin. There was no significant difference between the two groups with regard to the prevalence of postoperative VTE complications; however, aspirin was given in 63% of patients receiving mobile compression devices. Level of evidence: II.

The authors identified patients undergoing THA and then compared patients receiving LMWH with those receiving aspirin for VTE prophylaxis. No significant differences were reported between aspirin and LMWH in rates of pulmonary embolism (0.68% versus 0.64%) or deep veinous thrombosis (0.99% versus 0.84%). Mortality was significantly higher in the aspirin group (0.65% versus 0.51%). Level of evidence: III.

34. Hunt LP, Ben-Shlomo Y, Clark EM, et al; National Joint Registry for England, Wales and Northern Ireland: 90-day mortality after 409,096 total hip replacements for osteoarthritis, from the National Joint Registry for England and Wales: A retrospective analysis. Lancet 2013;382(9898):1097-1104. Medline  DOI

30. Anderson DR, Dunbar MJ, Bohm ER, et al: Aspirin versus low-molecular-weight heparin for extended venous thromboembolism prophylaxis after total hip arthroplasty: A randomized trial. Ann Intern Med 2013;158(11):800-806. Medline  DOI

The authors of this study assessed mortality within 90 days after THA: the rate decreased from 0.56% to 0.29% from 2003 to 2011. Factors decreasing the mortality risk included a posterior surgical approach and spinal versus general anesthesia. Level of evidence: III.

Patients in this study initially received dalteparin for 10 days of VTE prophylaxis after THA, and then were randomly assigned to receive either 28 days of additional dalteparin or aspirin. No significant difference was reported in postoperative VTE events between the two groups, and patients receiving dalteparin had more significant bleeding events. Level of evidence: I.

35. Hunt LP, Ben-Shlomo Y, Clark EM, et al; National Joint Registry for England and Wales: 45-day mortality after 467,779 knee replacements for osteoarthritis from the National Joint Registry for England and Wales: An observational study. Lancet 2014;384(9952):1429-1436. Medline  DOI

31. Intermountain Joint Replacement Center Writing Committee: A prospective comparison of warfarin to aspirin for thromboprophylaxis in total hip and total knee arthroplasty. J Arthroplasty 2012;27(1):1-9.e2. Medline  DOI

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Investigators enrolled consecutive patients undergoing THA or TKA into different VTE prophylaxis regimens. Group 1 received VTE risk stratification based on AAOS guidelines and received either aspirin 325 mg twice daily (standard risk) or warfarin with a goal international normalized ratio of 1.8 to 2.5 (elevated risk). Group 2, a comparator group, received warfarin with a goal international normalized ratio of 2.5 based on ACCP guidelines. The rate of VTE complications in patients receiving aspirin was significantly higher than the comparator group (7.9% versus 1.2%) and most of these events occurred in patients receiving TKA. Level of evidence: II.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

The authors of this study assessed mortality within 45 days after knee arthroplasty: the rate decreased from 0.37% to 0.20% from 2003 to 2011. Factors associated with increased mortality included myocardial infarction, cerebrovascular disease, and liver disease. The type of anesthesia (spinal versus general) did not affect the mortality rate. Level of evidence: III.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 2: Perioperative Assessment and Management

36. Helwani MA, Avidan MS, Ben Abdallah A, et al: Effects of regional versus general anesthesia on outcomes after total hip arthroplasty: A retrospective propensity-matched cohort study. J Bone Joint Surg Am 2015;97(3):186-193. Medline  DOI Researchers assessed patients who underwent THA and then stratified them according to type of anesthesia received. After propensity score matching, regional anesthesia was associated with a reduction in deep surgical site infection, length of stay, cardiovascular complications, and respiratory complications in comparison to general anesthesia; no difference in mortality was reported. Level of evidence: III.

The authors of this study evaluated patients who underwent primary TKA and assessed 30-day complications in patients receiving spinal versus general anesthesia. The spinal anesthesia group had lower superficial wound infections (0.68% versus 0.92%), blood transfusions (5.02% versus 6.07%), and overall complications (10.7% versus 12.3%). Mortality rates were similar between the two groups. Level of evidence: III. 38. Harsten A, Kehlet H, Ljung P, Toksvig-Larsen S: Total intravenous general anaesthesia vs. spinal anaesthesia for total hip arthroplasty: A randomised, controlled trial. Acta Anaesthesiol Scand 2015;59(3):298-309. Medline  DOI Patients undergoing THA were randomly assigned to receive either spinal or general anesthesia. General anesthesia resulted in shorter lengths of stay and less nausea. Patients in the regional anesthesia group had lower pain scores during the first 2 hours postoperatively, but higher pain scores after 6 hours postoperatively. Patients who received general anesthesia were more satisfied and reported they would request a change in anesthesia type less frequently. Level of evidence: I. 39. Harsten A, Kehlet H, Toksvig-Larsen S: Recovery after total intravenous general anaesthesia or spinal anaesthesia for total knee arthroplasty: A randomized trial. Br J Anaesth 2013;111(3):391-399. Medline  DOI

41. Halawi MJ, Vovos TJ, Green CL, Wellman SS, Attarian DE, Bolognesi MP: Opioid-based analgesia: Impact on total joint arthroplasty. J Arthroplasty 2015;30(12): 2360-2363. Medline  DOI The authors of this study assessed inpatient complications after THA or TKA in 575 patients: 98 patients had complications, 57 (58%) of which were caused by opioid use. The most common opioid-related complications were urinary retention, nausea, and delirium. The overall opioid-related complication rate was 8.5%. Level of evidence: III. 42. Lin J, Zhang L, Yang H: Perioperative administration of selective cyclooxygenase-2 inhibitors for postoperative pain management in patients after total knee arthroplasty. J Arthroplasty 2013;28(2):207-213.e2. Medline  DOI This systematic review of randomized trials evaluating the use of selective COX-2 inhibitors for postoperative pain control after TKA included eight studies and 571 patients. The results demonstrated decreased postoperative pain, less opioid consumption, and increased postoperative active knee ROM in patients receiving perioperative COX-2 inhibitors. No increased blood loss was associated with the use of selective COX-2 inhibitors. Level of evidence: II. 43. Schroer WC, Diesfeld PJ, LeMarr AR, Reedy ME: Benefits of prolonged postoperative cyclooxygenase-2 inhibitor administration on total knee arthroplasty recovery: A double-blind, placebo-controlled study. J Arthroplasty 2011;26(6suppl):2-7. Medline  DOI The authors enrolled 107 patients who underwent TKA. All patients received celecoxib preoperatively and during hospitalization. At the time of discharge, patients were randomly assigned to continue celecoxib for 6 weeks or receive a placebo for the same duration. The treatment group had better pain scores, less narcotic use, better ROM, and better functional scores. Level of evidence: I.

Patients undergoing TKA were randomly assigned to receive either spinal or general anesthesia. General anesthesia resulted in shorter hospital length of stay and less nausea and vomiting. Regional anesthesia resulted in lower pain scores during the first 2 hours postoperatively, but higher pain scores after 6 hours postoperatively. Patients who received general anesthetic used less postoperative morphine and ambulated earlier, and were more satisfied with their anesthetic and reported they would request a change in anesthetic type less frequently. Level of evidence: I.

44. Lee JK, Chung KS, Choi CH: The effect of a single dose of preemptive pregabalin administered with COX-2 inhibitor: A trial in total knee arthroplasty. J Arthroplasty 2015;30(1):38-42. Medline  DOI

40. Johnson RL, Kopp SL, Burkle CM, et al: Neuraxial vs general anaesthesia for total hip and total knee arthroplasty: A systematic review of comparative-effectiveness research. Br J Anaesth 2016;116(2):163-176. Medline  DOI

45. Buvanendran A, Kroin JS, Della Valle CJ, Kari M, Moric M, Tuman KJ: Perioperative oral pregabalin reduces chronic pain after total knee arthroplasty: A

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

37. Pugely AJ, Martin CT, Gao Y, Mendoza-Lattes S, Callaghan JJ: Differences in short-term complications between spinal and general anesthesia for primary total knee arthroplasty. J Bone Joint Surg Am 2013;95(3):193-199. Medline  DOI

This systematic review included prospective studies comparing regional versus general anesthesia in patients undergoing hip or knee arthroplasty. In the final analysis of 29 studies involving 10,488 patients, no differences were reported in mortality, postoperative infection, nausea, vomiting, or VTE complications between regional and general anesthesia. Level of evidence: II.

Researchers compared patients undergoing TKA who received preoperative pregabalin along with a COX-2 inhibitor with patients who received only a COX-2 inhibitor. Pregabalin administration resulted in lower acute pain scores and less analgesic consumption. Functional outcomes were similar between the two groups. Level of evidence: I.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

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Section 1: Hip and Knee

prospective, randomized, controlled trial. Anesth Analg 2010;110(1):199-207. Medline  DOI Investigators compared a treatment group receiving pregabalin administered before TKA and for 14 days postoperatively with a control group. Patients receiving pregabalin had less neuropathic pain, less opioid consumption, and greater knee ROM over the first 30 days postoperatively. However, sedation and confusion were more common on the day of and the day after surgery in patients receiving pregabalin. Level of evidence: I. 46. Spangehl MJ, Clarke HD, Hentz JG, Misra L, Blocher JL, Seamans DP: The Chitranjan Ranawat Award: Periarticular injections and femoral & sciatic blocks provide similar pain relief after TKA: a randomized clinical trial. Clin Orthop Relat Res 2015;473(1):45-53. Medline  DOI 1: Hip and Knee

This randomized trial involved comparison of femoral and sciatic nerve blocks with PAIs in patients receiving a multimodal pain regimen after TKA. Patients received either an indwelling femoral nerve block and single-shot sciatic block or a periarticular injection consisting of ropivacaine, epinephrine, ketorolac, and morphine. Mean pain scores and morphine consumption were similar between the two groups on postoperative day 1. More patients in the nerve block group had signs of nerve injury (12%) at 6-week follow-up. Level of evidence: I. 47. Ng FY, Ng JK, Chiu KY, Yan CH, Chan CW: Multimodal periarticular injection vs continuous femoral nerve block after total knee arthroplasty: A prospective, crossover, randomized clinical trial. J Arthroplasty 2012;27(6): 1234-1238. Medline  DOI This randomized crossover clinical trial involved 16 patients with bilateral knee osteoarthritis who underwent staged bilateral TKA. Patients were randomized to either receive a PAI consisting of ropivacaine, adrenaline, and triamcinolone or an indwelling femoral nerve block. During the second stage of the bilateral TKA, the patients received the opposite treatment. Pain and functional outcomes were similar between the two groups. Level of evidence: I.

50. Chan EY, Fransen M, Sathappan S, Chua NH, Chan YH, Chua N: Comparing the analgesia effects of single-injection and continuous femoral nerve blocks with patient controlled analgesia after total knee arthroplasty. J Arthroplasty 2013;28(4):608-613. Medline  DOI In this study, 200 patients undergoing TKA were randomly assigned to receive one of three postoperative pain control interventions: (1) patient-controlled analgesia, (2) single-injection femoral nerve block, or (3) continuous femoral nerve block. Femoral nerve block, both single-injection and continuous, resulted in less pain with knee motion, less opioid consumption, and fewer episodes of nausea and vomiting compared with patient-controlled anesthesia. Continuous nerve blocks were superior to single-injection nerve blocks. Level of evidence: I. 51. Shah NA, Jain NP: Is continuous adductor canal block better than continuous femoral nerve block after total knee arthroplasty? Effect on ambulation ability, early functional recovery and pain control: A randomized controlled trial. J Arthroplasty 2014;29(11):2224-2229. Medline  DOI In this study, patients undergoing TKA were allocated to receive either a continuous adductor canal block or a continuous femoral nerve block. Ambulatory outcomes such as staircase competency and ambulation distance were superior in the adductor canal block group, and pain control outcomes were similar between the two groups. Level of evidence: I. 52. Kim DH, Lin Y, Goytizolo EA, et al: Adductor canal block versus femoral nerve block for total knee arthroplasty: A prospective, randomized, controlled trial. Anesthesiology 2014;120(3):540-550. Medline  DOI

48. Liu W, Cong R, Li X, Wu Y, Wu H: Reduced opioid consumption and improved early rehabilitation with local and intraarticular cocktail analgesic injection in total hip arthroplasty: A randomized controlled clinical trial. Pain Med 2011;12(3):387-393. Medline  DOI

Investigators compared adductor canal versus femoral peripheral nerve blocks in 93 patients undergoing TKA. In the early postoperative period (6 to 8 hours), the adductor canal group demonstrated greater quadriceps strength. Quadriceps strength at hours 24 and 48 after surgery, as well as opioid consumption and overall pain control at all time points, were similar between the two groups. Level of evidence: I.

Investigators enrolled patients undergoing THA in a study of a PAI consisting of morphine, bupivacaine, betamethasone, and epinephrine that was compared with placebo treatment. The treatment group demonstrated improved pain control, less opioid consumption, and earlier mobilization. Level of evidence: I.

53. Abdallah FW, Brull R: Is sciatic nerve block advantageous when combined with femoral nerve block for postoperative analgesia following total knee arthroplasty? A systematic review. Reg Anesth Pain Med 2011;36(5):493-498. Medline  DOI

49. Dobie I, Bennett D, Spence DJ, Murray JM, Beverland DE: Periarticular local anesthesia does not improve pain or mobility after THA. Clin Orthop Relat Res 2012;470(7):1958-1965. Medline  DOI This study involved 96 patients undergoing THA to receive either placebo or a periarticular injection consisting of levobupivacaine and adrenaline. Postoperative results

26

demonstrated no difference in opioid consumption, mean time for stair activities, early mobilization, or length of stay. Level of evidence: I.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

In this systematic review, researchers assessed the efficacy of adding a sciatic nerve block to a femoral nerve block in patients undergoing TKA. Seven studies involving 391 patients were incorporated in the final analysis. The review demonstrated no clinically important analgesic advantages of a sciatic nerve block beyond 24 hours postoperatively. However, only two studies assessed posterior knee pain. Level of evidence: II.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 3

Blood Management Yatin Kirane, MD, PhD  Fred D. Cushner, MD

Abstract

Dr. Cushner or an immediate family member has received royalties from Smith & Nephew; is a member of a speakers’ bureau or has made paid presentations on behalf of Center for Healthcare Education, San Diego, CA, Pacira Pharmaceuticals, and Smith & Nephew; serves as a paid consultant to Pacira Pharmaceuticals and Smith and Nephew; has stock or stock options held in Aperion Biologic and Alter G; has received research or institutional support from Pacira Pharmaceuticals; and serves as a board member, owner, officer, or committee member of the Knee Society. Neither Dr. Kirane nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

© 2017 American Academy of Orthopaedic Surgeons

Introduction

1: Hip and Knee

Total hip arthroplasty and total knee arthroplasty are associated with significant perioperative blood loss, resulting in postsurgical anemia that in turn can necessitate blood transfusions. Perioperative blood loss can also result in significant surgical site hemarthrosis, which may lead to wound complications, increased risk of development of infection, and delayed recovery. Allogeneic blood transfusions have been associated with serious complications, such as incorrect blood component transfusion, disease transmission, allergic reactions, fluid overload, transfusion reactions, and immunosuppression. Overall, perioperative anemia and blood transfusions are associated with greater morbidity and mortality, longer hospital stay, and significantly higher hospital costs. Therefore, in this current climate of bundled payments, minimizing surgical blood loss and preventing postoperative anemia are critical to achieving successful clinical outcomes and reducing hospital costs. Numerous interventions have been suggested to minimize perioperative blood loss; however, orthopaedic surgeons lack consensus on the topic, and allogeneic transfusion rates still remain high at some institutions. An evidence-based multimodal individualized approach for blood conservation has been suggested.

Keywords: blood conservation has been suggested; total hip arthroplasty; total knee arthroplasty

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are two of the most commonly performed orthopaedic procedures in the United States and around the world. It has been estimated that more than 500,000 THA and more than 1 million TKA procedures (primary and revision procedures combined) will be performed in the United States alone in 2020.1 Historically, these procedures have been associated with substantial perioperative blood loss. In addition to the visible blood loss, a substantial amount of “hidden” blood loss is associated with these procedures as a result of extravasation into the tissues, residual blood accumulation into the joint, and blood loss attributable to hemolysis. The average total blood loss has been reported to be approximately 1.5 L with both THA and TKA procedures; more hidden blood loss is associated with TKA (49% of total blood loss) than THA (26% of total blood loss).2 Revision and bilateral arthroplasty procedures are associated with even greater blood loss. Anemia has been associated with higher rates of postoperative cardiovascular, genitourinary, and other complications, as well as mortality following total joint arthroplasty (TJA).3 Hemorrhage within the joint and periarticular tissues may result in hematoma formation, leading not only to drainage from the incision site but also delayed wound healing, wound dehiscence, and hence an increased risk of developing infection. Excessive hematoma also contributes to pain, swelling, decreased range of motion (ROM), prolonged rehabilitation, and a longer hospital stay. Anemia may further contribute to prolonged recovery by causing fatigue and inability to adequately participate in physical therapy. Furthermore, anemia may cause greater adverse effects in the presence of other coexisting medical conditions among elderly patients, a situation that is quite common in the joint arthroplasty patient population. Approximately 25% of patients undergoing an elective

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Section 1: Hip and Knee

1: Hip and Knee

THA or TKA have been reported to have anemia before surgery, whereas the prevalence of postoperative anemia has been reported to be approximately 51%.4 Perioperative blood loss may result in acute anemia, delayed recovery, and increased mortality risk, all of which may necessitate allogeneic blood transfusion. Blood transfusion rates for postoperative anemia have been reported to be 37% to 53% for primary THA (51% for hip arthritis and 61% following a femur neck fracture), 69% for hip hemiarthroplasty, 43% to 46% for primary TKA, 72% for bilateral TKA, 41% for revision TKA, and 72% for revision THA.5 With a unit of transfused blood costing an estimated $787.37,6 the incremental total hospitalization costs have been found to be $2,477, $4,235, and $8,594 higher for patients who underwent primary TKA, bilateral TKA, and revision TKA procedures, respectively, and received blood transfusion as compared with those who did not receive transfusion.7 Furthermore, in addition to higher costs, allogeneic blood transfusion carries a risk— albeit a small risk—of serious complications such as incorrect blood component transfusion, disease transmission, allergic reactions, fluid overload, transfusion reactions, and immunosuppression. In contrast, reduced blood loss translates to better wound healing, quicker rehabilitation, shorter length of hospital stay, higher hemoglobin levels at discharge, fewer medical complications, faster recovery, and improved patient satisfaction. Predictors of marked blood loss necessitating blood transfusion include preoperative anemia, older age, higher body weight, multiple comorbidities, increased surgical time, lateral retinacular release, and use of postoperative anticoagulation.8,9 Despite known risks, surgical anemia due to acute blood loss has been considered by many to be a routine and an acceptable complication of major surgical procedures. The need for blood management protocols to reduce the perioperative blood loss, the associated morbidity, and the allogeneic blood transfusion rates to improve clinical outcomes of joint arthroplasty surgery is increasingly recognized. Minimizing surgical blood loss and preventing postoperative anemia are critical to achieving successful clinical outcomes. Numerous interventions have been suggested to minimize perioperative blood loss; however, orthopaedic surgeons lack consensus on the topic, and allogeneic transfusion rates remain unacceptably high. Several authors have suggested evidence-based multimodal blood management protocols to minimize perioperative blood loss and to achieve improved clinical outcomes, decreased procedural costs, and shorter hospital stays. Furthermore, blood conservation protocols need to be individualized by means of algorithms based on the patient’s preoperative

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

hemoglobin level and medical comorbidities, the complexity of the planned procedure, the anticipated blood loss, and the need for transfusion. Blood Conservation Strategies Preoperative Strategies: Preoperative Screening and Treatment of Anemia Approximately 24% to 44% of patients have been reported to be anemic before THA or TKA surgery.4 Preoperative anemia has been associated with higher rates of postoperative complications and mortality following TJA.3 Therefore, timely detection and management of preoperative anemia, nutritional or metabolic deficiencies, and other modifiable risk factors is extremely important in optimizing patient physiology before surgery. Preoperative assessment should include a complete workup for anemia and nutritional status in addition to routine investigations and consultation with a hematologist or other appropriate specialist if deemed necessary. Authors of a 2016 study recommended hemoglobin screening at the time of indication for arthroplasty by using a noninvasive cutaneous pulse co-oximeter followed by complete blood count. They recommended additional laboratory testing and referral to a hematologist for patients with hemoglobin levels lower than 12.10 Specifically, the preoperative evaluation should include obtaining patients’ personal and family history of bleeding, thromboembolic disease, current medication review, complete blood count with differential, and other appropriate patient-specific laboratory investigations. Optimization of the patient’s general health—which may include smoking cessation, weight loss, management of blood pressure and diabetes, prescribing vitamins, iron, and other nutritional supplements, and stopping use of antiplatelet and anticoagulation medications— should be accomplished early.11 Preoperative hemoglobin levels lower than 11 g/dL, body mass index (BMI) less than 27 kg/m2 , age older than 75 years, and male sex all are factors that have been associated with an increased requirement for postoperative blood transfusion. Therefore, individualized risk stratification and a multidisciplinary approach have been suggested for early diagnosis and treatment of preoperative anemia. The goal should be to optimize the patient’s hemoglobin level above 12 g/dL because lower levels have been correlated with a threefold increase in transfusion requirement. Nonsteroidal Anti-inflammatory and Anticoagulant Medications NSAIDs are widely used for perioperative analgesia. Nonselective NSAIDs are known to impair platelet aggregation

© 2017 American Academy of Orthopaedic Surgeons

Chapter 3: Blood Management

Vitamins and Iron Supplementation

Patients with preoperative anemia can be treated with a healthy diet, vitamin B12 , folate, oral or intravenous (IV) iron, and erythropoiesis-stimulating agents. Approximately 4 to 6 weeks of nutritional supplementation before the planned surgery is necessary for effective treatment. Lower transfusion and infection rates have been reported following TKA in patients with hemoglobin levels below 8 mg after receiving daily supplementation of iron (256 mg; 80 mg Fe2+), vitamin C (1,000 mg), and folate (5 mg) for 30 to 45 days.14 However, higher levels of iron supplementation, especially when administered in the absence of iron deficiency, have been associated with constipation, heartburn, abdominal pain, and other side effects. Erythropoietin

Erythropoietin (EPO), a glycoprotein that is naturally secreted by renal pericapillary cells in response to reduced tissue oxygen tension such as occurs in an anemic state, acts on bone marrow to increase red blood cell differentiation and maturation. Epoetin α, which is human EPO produced in a laboratory by means of recombinant technology, has the same physiologic effects and is commonly used for patients with chronic renal disease and those undergoing chemotherapy. Preoperative epoetin

© 2017 American Academy of Orthopaedic Surgeons

Table 1

Erythropoietin Dosing Schedules Dose

Schedule

600 IU/kg

4 doses: Preoperative days 21,14, 7, and 0

300 IU/kg

15 daily doses: Preoperative day 10 to postoperative day 4

150 IU/kg

9 daily doses: Preoperative day 5 to postoperative day 3

Reproduced from Levine BR, Haughom B, Strong B, Hellman M, Frank RM: Blood management strategies for total knee arthroplasty. J Am Acad Orthop Surg 2014;22(6):361-371.

1: Hip and Knee

and prolong bleeding time by acting on cyclo-oxygenase (COX)-1 and -2 enzymes of the prostaglandin formation process. However, COX-2–selective NSAIDs such as celecoxib and etoricoxib are believed to reduce pain and inflammation without affecting platelet aggregation or bleeding time. COX-2 inhibitors are often an aspect of multimodal pain management after arthroplasty,12 and they can be safely used in most patients with consideration given to their cardiovascular and other side effects. Several other allopathic and alternative herbal medications can prolong bleeding time by affecting various levels of the coagulation cascade and can substantially increase perioperative bleeding. Therefore, all medications with known side effects on coagulation should be stopped before surgery. According to the current clinical practice guidelines, anticoagulant and antiplatelet medications such as warfarin, aspirin, clopidogrel, and rivaroxaban should be stopped before the planned surgery to normalize bleeding time.13 However, benefits of stopping these medications before surgery need to be weighed against the patient’s cardiac risk, and the treatment needs to be individualized. To maximize patient safety, the prescribing physician should weigh in regarding if and when to stop these medications rather than use a general rule applied to all patients undergoing arthroplasty procedures.

injections have been more effective than has preoperative autologous blood donation (PAD) in maximizing preoperative hemoglobin in patients undergoing TKA15 and reducing the need for allogeneic blood transfusions even in high-risk patients with anemia.16 Several preoperative and postoperative dosing regimens have been described17 (Table 1). Although effective, EPO treatment is expensive: the average price per patient is equivalent to two to three units of PAD or three to four units of allogenic blood.18 In a 2015 efficacy/cost-analysis study, EPO treatment was found to have no effect on the length of hospital stay and was not cost effective despite the reduced need for postoperative blood transfusions. Nevertheless, the use of EPO is recommended for patients at higher risk of allogenic transfusion, such as those with preoperative anemia (hemoglobin level less than 13 g/dL) and low body weight (less than 50 kg) who are undergoing revision or bilateral surgery for which considerable blood loss is expected. Autologous Blood

PAD involves procuring one to two units of the patient’s own blood before surgery. The donated autologous blood is processed, stored, and transfused back to the patient during or after surgery. PAD can be performed at least 3 weeks before the planned surgery, for anticipated major blood loss in patients with hemoglobin greater than 11 g/dL and weight greater than 110 lb.19 PAD was popular in the United States in the late 1980s, when decreased need for allogeneic blood transfusions with the use of PAD was reported.20,21 However, in recent years, PAD has become less common for a variety of reasons. First, patients with preoperative anemia are not candidates for PAD. This severely limits the usefulness of this modality, because patients with anemia are most likely to require allogeneic transfusion postoperatively. The procedure is inconvenient and expensive; it requires advance planning

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Section 1: Hip and Knee

as well as storage and preparation of the donated blood, and it carries a risk of clerical error. Phlebotomy-induced anemia, bacterial contamination, and infection are additional risks associated with an autologous blood donation program. In addition, it may be wasteful and unnecessary for patients who do not have anemia.22,23 Furthermore, preoperative epoetin α treatment has been more effective than PAD in maximizing preoperative hemoglobin for patients undergoing TKA.15 There is currently no consensus regarding the efficacy/cost-benefit of PAD and, therefore, its routine use is not recommended. Hemodilution 1: Hip and Knee

Acute normovolemic hemodilution (ANH) involves harvesting a patient’s whole blood along with simultaneous infusion of acellular fluids (colloids or crystalloids) at the time of or just before surgery. This is followed by perioperative reinfusion of the procured autologous blood, thereby resulting in a reduced net loss of red blood cells. This procedure has been indicated for patients who have preoperative hemoglobin levels higher than 10 g/dL and for whom procedures in which substantial blood loss is anticipated are planned. Although cumbersome and time consuming, ANH has been found to be equal to PAD in effectiveness for patients undergoing THA and TKA procedures. Furthermore, ANH is less expensive and has a smaller risk of clerical error, bacterial contamination, and blood wastage as compared with PAD.24 The utility of hemodilution currently is limited as a result of considerably reduced blood loss due to multimodal blood conservation protocols and newer drugs such as tranexamic acid (TXA). Hemodilution may still be valuable in patients who refuse allogeneic blood transfusion due to religious beliefs (for example, Jehovah’s Witnesses).

Hypotensive Anesthesia

With the use of hypotensive epidural anesthesia, blood loss is reduced by maintaining a low mean arterial blood pressure (typically 50 to 60 mm Hg) throughout the surgical procedure. This is achieved by decreasing the conduction of the cardioacceleratory fibers of the thoracic sympathetic chain via an epidural dermatome block at T2 level. Hypotensive anesthesia has been shown to effectively reduce intraoperative blood loss by about 38% to 45%; however, it may lead to tissue hypoperfusion, bradycardia, and other serious cardiopulmonary complications, and it should be used with extreme caution in patients with cardiopulmonary, renal, cerebral, or peripheral vascular diseases.29,30

Intraoperative Strategies

Surgical Technique

Tourniquets

The importance of meticulous surgical techniques in limiting the amount of intraoperative blood loss cannot be overstated. Examples of surgical techniques that are particularly helpful for blood conservation include careful dissection, limited incision and soft-tissue release, gentle handling of soft tissues, appropriate use of electrocautery, and administration of periarticular and intra-articular epinephrine mixed with saline and other medications.

Thigh tourniquets have been routinely used for TKA because they allow a bloodless surgical field, improved cement interdigitation, and decreased surgical time. However, the local tissue ischemia and subsequent reactive hyperperfusion with tourniquet use can result in local muscle damage, neurapraxia, thigh pain, delayed wound healing, increased joint swelling and stiffness, and thromboembolic events.25 There is some controversy regarding the optimal time for release of a tourniquet. Researchers compared clinical outcomes in relation to the timing of tourniquet use in a 2014 nonrandomized prospective cohort study involving 90 patients.26 The participants were divided into three groups on the basis of the timing of tourniquet use—that is, from incision to wound closure, from incision to after cement hardening, and only

30

during cementing. Use of a tourniquet only during cementing led to lower serum markers for inflammation and muscle damage, such as C-reactive protein, interleukin-6, creatine kinase, and myoglobin. However, there was no difference in the clinical outcomes in terms of Hospital for Special Surgery knee scores, ROM, estimated blood loss, swelling ratio, visual analog scale pain score, and length of hospital stay. Release of the tourniquet after wound closure has been shown to significantly decrease surgical time without affecting overall perioperative blood loss, or drop in hemoglobin level or transfusion requirement.27 In a poll at the 2009 Annual Meeting of the American Association of Hip and Knee Surgeons regarding current practice patterns in primary THA and TKA, 37% of the respondents used a tourniquet in all cases irrespective of any prior vascular problems, 58% of the respondents avoided tourniquet use if a patient has known vascular problems, and 5% of the respondents used a tourniquet only during exposure and cementation.28

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

Bipolar Sealer Versus Electrocautery

Bipolar sealer uses radiofrequency to achieve coagulation of blood vessels. Because of continuous simultaneous flow of saline, the tip of the bipolar sealer remains cool, causing less damage to the surrounding tissues. There have been mixed reports regarding the efficacy of the bipolar sealer as compared with the conventional electrocautery

© 2017 American Academy of Orthopaedic Surgeons

Chapter 3: Blood Management

Topical Hemostatic Agents

A variety of topical hemostatic agents such as platelet-rich plasma, fibrin sealant, cellulose, collagen agents, and thrombin have been used to reduce blood loss during TJA. Typically, the selected topical hemostatic agent is sprayed inside the wound before closure. Although there were a few early favorable results regarding efficacy,36 there is no conclusive evidence in support of routine use of these agents. In a 2014 meta-analysis comprising eight randomized controlled trials (RCTs) involving 641 patients, substantially reduced postoperative drainage and blood transfusion rates were observed, as well as improved postoperative knee ROM, with the use of a fibrin sealant product.37 However, there were no substantial differences in terms of total blood loss or other adverse events such as fever, infection, or hematoma. It was concluded that the use of fibrin sealant was effective and safe as a hemostatic therapy during TKA.37 However, other reports suggest

© 2017 American Academy of Orthopaedic Surgeons

that the fibrin sealant and other topical hemostatic agents do not have any substantial effect on reducing blood loss or transfusion requirement.38,39 Currently, routine use of these agents remains controversial. Antifibrinolytic Agent: Tranexamic Acid

Several antifibrinolytic agents have been used to limit blood loss in TJA, including desmopressin, TXA, ε-­aminocaproic acid, and aprotin. TXA is by far the most studied and widely accepted drug, and it is being increasingly incorporated into perioperative blood management protocols. Originally discovered in 1962, TXA (trans form of 4-aminomethyl-cyclohexane-carbonic acid) competitively binds to the lysine-binding site on plasminogen, which prevents fibrin from binding to the plasminogen– plasmin tissue activator complex and thus inhibits fibrin clot degradation and bleeding.40 With a half-life of 80 to 120 minutes, TXA has been reported to rapidly penetrate the synovial fluid and membrane, reaching the same concentration as in plasma within 15 minutes and peak concentration within 1 hour after IV administration. The usual dose of IV TXA is 20 mg/kg, and the maximum dose is 2,000 mg. Because the kidneys provide the major route of elimination, the IV dose of TXA needs to be reduced to 50% for patients with renal impairment for a glomerular filtration rate (GFR) of 0.5 mL/min, 25% for a GFR 10 to 50 mL/min, and 10% for a GFR of 10 mL/ min.40 The absolute contraindications to TXA include a known allergy to the agent, an ongoing acute venous or arterial thrombosis, and an intrinsic risk or a history of thrombosis or thromboembolism. Subarachnoid hemorrhage also can be considered an absolute contraindication. Caution needs to be exerted when using TXA in the presence of cardiac or peripheral vascular disease, seizures, and acute renal failure, although further studies are needed to fully define all the risks associated with TXA.41 Recent reports indicate that TXA has been associated with decreased perioperative blood loss, higher postoperative hemoglobin levels, lower blood transfusion rates, lower complication rates, and decreased length of hospital stay.41,42 In patients undergoing TKA, TXA has been shown to decrease total blood loss by 30%, the drainage volume by nearly 50%, and the transfusion requirement by 47%.43 For patients in whom intravenous TXA is contraindicated, 2 to 4 g of TXA can be safely injected inside the joint before deflation of the tourniquet. Intra-articular administration of TXA has been found to have clinical outcomes comparable with those seen after IV administration, with significantly higher hemoglobin levels during the immediate postoperative period and at discharge. The requirement for blood transfusion was seen to decrease to 5% after intra-articular TXA

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

1: Hip and Knee

in terms of amount of perioperative blood loss, the need for blood transfusion, and other clinical outcomes. Some authors have reported substantially reduced blood loss, postoperative hemoglobin drop, and transfusion requirement with the use of a bipolar sealer as compared with electrocautery in TJA.31 Bipolar sealers are expensive tools; the incremental costs per case have been estimated to be approximately $676.32 Researchers in one study observed significantly fewer blood transfusions, lower incidence of hematomas, and significantly shorter lengths of hospital stay after primary THA involving the use of a bipolar sealer. However, no effect on the total hospital costs was found. It was concluded that the higher supply costs associated with the use of a bipolar sealer were likely offset by the reduced hospital inpatient and operating room costs.32 Another group of investigators reported that the use of a bipolar sealer for simultaneous bilateral TKA was associated with a 35% lower blood transfusion rate as compared with the use of conventional electrocautery.33 However, no significant difference was observed in terms of decrease in hemoglobin level, total blood loss, or length of stay. In other studies by members of the same group of investigators, the use of a saline-coupled bipolar sealing device in revision of infected THA resulted in shorter surgical times, less blood loss, and smaller perioperative decrease in hemoglobin level,34 whereas the device’s use in revision procedures for infected TKA was not clinically or economically justified.35 The bipolar sealing device shows promise as a blood-loss reduction tool, especially in simultaneous bilateral TKA and revision THA procedures; however, the savings and clinical benefits associated with the reduced transfusion rates need to be evaluated against the per-case expense of the device.

31

1: Hip and Knee

Section 1: Hip and Knee

as compared with 22% among those who did not receive TXA.42 Intra-articular injection of TXA results in 70% of the plasma concentration after IV administration with minimal systemic hypercoagulability effects.44 Intra-­ articular use of TXA has been associated with improved knee function in the initial 6 weeks of the immediate postoperative period, as evidenced by significantly improved Knee Society Scores (ability to walk, negotiate stairs up and down, arise from a chair, and the use of support).42 Furthermore, combined intra-articular administration of TXA and epinephrine significantly reduced total blood loss, hidden blood loss, and transfusion rate as compared with TXA alone—without increasing the risks of thromboembolic and hemodynamic complications—in both THA45 and TKA.46 There are several recommendations regarding TXA dosing, and further investigations are warranted to determine the optimal dosing and dosing regimen of TXA. Typically, two 20-mg/kg (approximately 2 g) doses of IV TXA are administered; the first dose is given before inflation of the tourniquet, and the other dose is given postoperatively. Recent evidence indicates that additional topical TXA doses higher than 2 g appear to be more efficacious than are lower doses.47 In per-patient cost analysis studies, TXA ($103.08) was found to be significantly more cost effective than preoperative 3-week iron supplementation ($1773.48),1-week EPO regimen ($268.88),48 and reinfusion drains ($581.89),49 as well as autologous blood transfusion ($787).6

thus increasing the hospital costs by $538 for THA and $455 for TKA.51 Increasing impetus to reduce hospital costs has caused many to reevaluate the postoperative protocol and question the usefulness of wound drains. Several authors now recommend against using wound drains and propose same-day discharge following TJA.51 With a multimodal blood conservation protocol including medications such as TXA, the risk of hematoma formation and the need for blood transfusion after a TJA are greatly reduced. In a double-blind randomized placebo-controlled trial, investigators reported that TXA treatment without drainage results in substantial reduction in blood loss and the amount of blood transfusions required without increasing the rate of adverse events.52 In a prospective cohort study, investigators categorized 63 patients undergoing bilateral TKA into bilateral-drain, unilateral-drain and no-drain groups, and no substantial differences in the short- or long-term clinical outcomes were observed. It was concluded that wound suction drains are not necessary after TKA.53 In a meta-analysis of six RCTs, a research team concluded that wound drains did not offer any significant benefits in terms of postoperative recovery.54 In another meta-analysis of 20 RCTs, investigators observed a reduced need for dressing reinforcement but an increased need for blood transfusion with the use of a closed suction drain after THA, and it was concluded that wound drains following THA likely do more harm than good.55

Postoperative Strategies

Cold Compressive Dressing

Wound Drains

Cold compressive dressing is thought to decrease the amount of internal blood loss, pain, and swelling. Despite the lack of adequate scientific evidence to support these beliefs, cold compressive dressings (such as Cryo/Cuff, DJO Global) are routinely used following TKA.

Wound drains have been used in orthopaedic surgery for decades to prevent fluid collection and hematoma formation at the surgical site. Traditionally, closed suction drains have been used after TJA to prevent hematoma formation, and thereby to reduce the risk of infection, relieve pain and stiffness, prevent wound dehiscence, improve wound healing, and allow for early mobilization and a shorter length of hospital stay.50 However, the use of wound drains has become controversial in recent years. Opponents of wound drains consider them a channel for potential retrograde transmission of bacteria. Complications such as accidental suturing of the drain, entrapment, and drain breakage during removal are well known, and these may require reopening the surgical wound in the operating room. Furthermore, closed suction drains are thought to result in increased blood loss because of continuous negative pressure. There have been various recommendations regarding optimal drain management, releasing pressure, clamping, and the timing of drain removal. Typically, patients need to be hospitalized for a day or two for drain management,

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Blood Salvage and Reinfusion

Blood salvage and reinfusion techniques involve collection of the blood shed during surgery using a cell saver system, and postoperatively, using a recollection drain. The collected blood is filtered, washed, and then reinfused into the patient within 6 to 8 hours. There are mixed reports regarding the efficacy of blood salvage and reinfusion. Some authors have reported lower total blood loss and higher postoperative hemoglobin levels with the implementation of reinfusion technique following THA as well as TKA.56 However, reinfusion systems are expensive and have potential complications such as contamination, infection, and coagulopathy due to circulating fibrin-split products and cytokines. In a prospective RCT involving 1,759 patients undergoing THA or TKA procedure, autologous intraoperative and postoperative blood salvage

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Chapter 3: Blood Management

Table 2

Complication Risks Associated With Allogeneic Blood Transfusion Complication

Incidence

Infectious HIV infection

1:1,900,000

Hepatitis B virus infection

1:180,000

Hepatitis C virus infection

1:1,600,000

Bacterial contamination

1:3,000

Cardiopulmonary Transfusion-associated circulatory overload

1:5,000

Acute lung injury

1:50,000

Systemic

Allogeneic Blood Transfusion

Fever or allergic reaction

1:200

Historically, THA and TKA procedures have resulted in substantial perioperative blood loss, often requiring the transfusion of one or more units of blood, which has been a part of the routine postoperative protocol for years. However, allogeneic blood transfusion has significant risks, including incorrect blood component transfusion, disease transmission, allergic reactions, fluid overload, transfusion reaction, and immunosuppression.60 The risks17 have been quantified in Table 2. Furthermore, allogeneic blood transfusion is associated with significant costs. The costs associated with collecting, testing, processing, storing, and cross-matching one unit of blood have been estimated to be approximately $787.6 Compared with patients who did not require a blood transfusion, the incremental total hospitalization costs for those who required a transfusion have been estimated to be $2,477 (12%), $4,235 (15%), and $8,594 (35%) higher for a primary TKA, a bilateral TKA, and a revision TKA, respectively.7 The concept of transfusion triggers has been popular in the past couple of decades. Traditionally, the 10/30 rule dictated that a blood transfusion was required in postsurgical patients if the hemoglobin level fell below 10 g/dL, the hematocrit level fell below 30%, or both. In recent years, more restrictive transfusion triggers have been followed. Evidence-based restrictive transfusion strategy has been recommended by the American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies61 as well as the AABB (formerly the American Association of Blood Banks).62 According to these guidelines, the threshold for transfusion for a hemodynamically stable postsurgical patient is a hemoglobin level lower than 7 to 8 g/dL with clinical symptoms of anemia. Thus, the decision to undertake transfusion in a patient is based

Hemolytic transfusion reaction

1:6,000

Fatal hemolytic reaction

1:1,000,000

Anaphylaxis

1:50,000

© 2017 American Academy of Orthopaedic Surgeons

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devices were found to be expensive and ineffective.57 The unit cost of a reinfusion system ($581.89) is substantially higher than those of a standard drain ($7.56) and TXA ($35.91/g).49 In a recent meta-analysis of 43 RCTs involving 5,631 patients, investigators observed that although cell salvage reduced bleeding and transfusion requirements in THA and TKA in earlier studies, more recently published studies (2010 to 2012) indicate contradictory results. The investigators attributed this finding to the changes in blood transfusion management practices.58 In another recent meta-analysis, researchers confirmed the efficacy of the reinfusion technique in reducing the need for allogeneic blood transfusion after THA and TKA, but they emphasized that further research is warranted regarding the risks of serious complications and safety of this technique.59

Reproduced from Levine BR, Haughom B, Strong B, Hellman M, Frank RM: Blood management strategies for total knee arthroplasty. J Am Acad Orthop Surg 2014;22(6):361-371.

not only on the laboratory values, but also on objective signs and symptoms such as tachycardia, feeling of weakness or dizziness, comorbidities, severity of illness, rate and amount of hemorrhage, and the patient’s capacity to cope with the hemorrhage. Blood transfusion rates for postoperative anemia have been reported to be as high as 37% to 53% for primary THA (51% for hip arthritis and 61% after a femoral neck fracture), 69% for hip hemiarthroplasty, 43% to 46% for primary TKA, 72% for bilateral TKA, 41% for revision TKA, and 72% for revision THA.5 With implementation of an individualized patient blood management protocol, researchers reported a 44% decrease in the transfusion rate and a significant reduction in complications, readmissions, and length of hospital stay.63 With the implementation of a practical multimodal blood conservation protocol and adherence to evidence-based guidelines, it is possible to significantly reduce blood transfusion rates following TJA. Complex Cases Bilateral TJA

An increasing number of patients are undergoing simultaneous bilateral THA (especially via the direct anterior approach) or TKA procedures because of the convenience of a single trip to the operating room, one-time anesthesia,

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Section 1: Hip and Knee

1: Hip and Knee

and one-time surgery. However, simultaneous bilateral TJA procedures can result in substantially greater blood loss, and there is an increased risk of requiring a blood transfusion in the perioperative period. Blood transfusion rates for bilateral TKA have been reported to be as high as 72%.5 A multimodal patient-specific blood conservation protocol becomes critical when planning bilateral THA or TKA procedures. Of all the different modalities, TXA seems to have the greatest effect on blood conservation. In a retrospective study involving 103 patients who underwent simultaneous bilateral TKA, investigators observed significantly higher hemoglobin levels on the first postoperative day and almost a 70% decrease in the incidence of blood transfusion with the administration of TXA.64 Revision Knee Arthroplasty

With the growth of the aging population and the increasing number of primary THA and TKA procedures being performed each year, the number of revision arthroplasties is on the rise. Blood transfusion rates for revision arthroplasty procedures have been quite high. Based on nationwide hospital and blood bank data, researchers reported 72% and 41% blood transfusion rates for revision THA and TKA procedures, respectively.5 A blood conservation protocol incorporating TXA was shown to significantly decrease the blood transfusion rates among patients undergoing revision TKA.65 Sickle Cell Anemia

Patients with sickle cell disease undergoing THA or TKA have an increased risk of perioperative complications, especially when a blood transfusion is required.66 There is no consensus regarding the optimal blood management for patients with sickle cell anemia who are undergoing TJA. A multimodal blood conservation protocol is of utmost importance for these patients to avoid a sickle cell crisis. In a 2013 multicenter randomized trial, researchers found that preoperative blood transfusions in patients with the hemoglobin SS form of sickle cell disease were associated with decreased risks of serious complications, particularly acute chest syndrome.67 Maintenance of hydration and optimal pain control are essential to prevent sickle cell crisis. In general, the patient should be treated in consultation with a hematologist during the perioperative period.67 Religious Objections to Blood Transfusions

Researchers reported excellent outcomes of TKA procedures in patients who are Jehovah’s Witnesses using a specific blood management strategy.68 Preoperative evaluation and treatment were conducted by a coordinated team consisting of internists, hematologists, intensivists, and anesthesiologists. Preoperative optimization of patients’ red blood cell mass was achieved using iron and folate supplements. Patients with hemoglobin levels between 13 g/dL and 15 g/dL were treated with a combination of acute normovolemic hemodilution and EPO therapy. Patients with a hemoglobin level of less than 13 g/dL were initially treated with EPO alone, followed by combination therapy of intravenous iron and blood salvage if their hemoglobin levels remained lower than 13 g/dL. Surgery was performed using a less invasive approach, with emphasis given to meticulous hemostasis, decreased surgical time, and avoidance of a drain if possible. Postoperative measures included microvenipunctures, iron supplements, and EPO therapy. Summary Perioperative management of patients undergoing TJA is evolving. Blood loss following THA or TKA procedures that necessitates postoperative blood transfusion is no longer accepted as routine. Several authors have emphasized the importance of implementing individualized risk stratification and multimodal blood conservation protocols. Such multimodal approaches consist of numerous preoperative, intraoperative, and postoperative measures. Preoperative measures are focused on timely diagnosis and treatment of preoperative anemia, as well as on optimization of the patient’s red blood cell mass and general health using iron and vitamin supplementation, EPO injections, or both. Intraoperative strategies focus on minimizing blood loss by means of meticulous surgical technique, hypotensive anesthesia, bipolar sealer, topical hemostatic agents, and antifibrinolytic agents such as TXA. Postoperative measures include reinfusion and allogeneic blood transfusion in select patients. The evidence-based restrictive transfusion trigger strategy is recommended for allogeneic blood transfusion in hemodynamically stable patients to avoid unnecessary risks associated with blood transfusion. The ultimate goal is to minimize not only the need for blood transfusion for patients undergoing TJA procedures, but also to limit surgical site hemarthrosis and wound complications.

Some patients may refuse blood transfusions because of their religious beliefs, such as those who are Jehovah’s Witnesses. Therefore, effective blood conservation protocol is critical in these patients to ensure safe and transfusion-free procedures with minimal complications.

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Chapter 3: Blood Management

Key Study Points

Annotated References 1. Kurtz SM, Ong KL, Lau E, Bozic KJ: Impact of the economic downturn on total joint replacement demand in the United States: Updated projections to 2021. J Bone Joint Surg Am 2014;96(8):624-630. Medline  DOI Data from the Nationwide Inpatient Sample (1993 to 2010) with United States Census and National Health Expenditure data were used to quantify historical trends in TJA rates, including the two economic downturns in the 2000s. Future TJA procedures were estimated using a regression model incorporating the growth in population and rate of arthroplasty procedures as a function of age, sex, race, and census region using the National Health Expenditure as the independent variable. 2. Sehat KR, Evans RL, Newman JH: Hidden blood loss following hip and knee arthroplasty. Correct management of blood loss should take hidden loss into account. J Bone Joint Surg Br 2004;86(4):561-565. Medline 3. Viola J, Gomez MM, Restrepo C, Maltenfort MG, Parvizi J: Preoperative anemia increases postoperative complications and mortality following total joint arthroplasty. J Arthroplasty 2015;30(5):846-848. Medline  DOI This single-institution, large case-controlled study was designed to examine the association between preoperative anemia and adverse outcomes following TJA. Data were collected from the authors’ institutional database of patients who underwent primary and aseptic revision TJA. Multivariate analysis was used to determine the effect of preoperative anemia on the incidence of medical complications, infection, hospital length of stay, and mortality. The authors observed that patients with anemia had a

© 2017 American Academy of Orthopaedic Surgeons

4. Spahn DR: Anemia and patient blood management in hip and knee surgery: A systematic review of the literature. Anesthesiology 2010;113(2):482-495. Medline  DOI In this systematic literature review, the characteristics of perioperative anemia, its association with clinical outcomes, and the effects of patient blood management interventions on these outcomes in patients undergoing major orthopaedic surgery were determined. Among patients undergoing THA or TKA and hip fracture surgery, preoperative anemia was highly prevalent (24% to 44%, respectively), and so was postoperative anemia (51% and 87%, respectively) in patients undergoing THA or TKA. Perioperative anemia was associated with a blood transfusion rate of 45% ± 25% and 44% ± 15%, postoperative infections, poorer physical functioning and recovery, increased length of hospital stay and mortality.

1: Hip and Knee

• TJA procedures are associated with substantial blood loss, which can compromise patient recovery and overall clinical outcomes by causing greater morbidity and mortality, longer hospital stay, and significantly higher hospital costs. • Multimodal blood conservation strategies comprising preoperative, intraoperative, and postoperative measures can effectively reduce blood loss associated with TJA. • Preoperative anemia is a major factor in predicting transfusion requirements; therefore, patients should be adequately screened and treated for anemia preoperatively. • TXA is now the gold standard in blood loss prevention in TJA, and intravenous or intra-articular TXA should be considered for every patient undergoing TJA.

higher rate of complications (odds ratio, 2.11), including cardiovascular 26.5% versus 11.8%, and genitourinary 3.9% versus 0.9%, and preoperative optimization was recommended to reduce these complications.

5. Verlicchi F, Desalvo F, Zanotti G, Morotti L, Tomasini I: Red cell transfusion in orthopaedic surgery: A benchmark study performed combining data from different data sources. Blood Transfus 2011;9(4):383-387. Medline The authors report on a study done by combining information from different data sources about blood transfusion practices. They observed that 56.8% of cases required transfusion of red blood cells, and that the likelihood of receiving a transfusion varied depending on the patient’s sex (49% for males, 60% for females), age, and on the surgical procedure. About 70% of patients undergoing procedures following femoral fractures and for revisions of hip replacement required transfusion. 6. Tuttle JR, Ritterman SA, Cassidy DB, Anazonwu WA, Froehlich JA, Rubin LE: Cost benefit analysis of topical tranexamic acid in primary total hip and knee arthroplasty. J Arthroplasty 2014;29(8):1512-1515. Medline  DOI This retrospective cohort study, which involved 591 consecutive patients (311 experimental and 280 controls), was designed to perform cost-benefit analysis of topical TXA in patients with primary THA and TKA. The authors observed that the use of topical TXA during THA and TKA procedures resulted in reduction in the blood transfusion rate from 17.5% to 5.5%, significant increase in the postoperative hemoglobin level, and significant decrease in delta hemoglobin without an increase in adverse events (all P < 0.001). This resulted in a savings of $83.73 per patient, and disposition of patients to home rather than a subacute nursing facility. 7. Nichols CI, Vose JG: Comparative risk of transfusion and incremental total hospitalization cost for primary unilateral, bilateral, and revision total knee arthroplasty procedures. J Arthroplasty 2016;31(3):583-589.e1. Medline  DOI This retrospective chart review of 513,558 primary unilateral, 33,977 bilateral, and 32,494 revision TKA procedures performed between January 2008 and June 2014 evaluated the comparative risk of autologous and

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Section 1: Hip and Knee

allogeneic blood transfusion, in-hospital complications, and incremental total hospitalization costs for primary unilateral, simultaneous bilateral, and revision TKA procedures. Patient age older than 65 years, female sex, Northeastern location, large hospitals, and higher Charlson score were significantly associated with higher transfusion risk. Incremental total hospitalization cost among those receiving a transfusion was $2477 (primary unilateral), $4235 (bilateral), and $8594 (revision), respectively, compared with those without transfusion. The authors concluded that transfusion risk remains a significant burden in select patient populations and procedures with significant incremental cost of receiving a transfusion after knee arthroplasty procedures.

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8. Sizer SC, Cherian JJ, Elmallah RD, Pierce TP, Beaver WB, Mont MA: Predicting blood loss in total knee and hip arthroplasty. Orthop Clin North Am 2015;46(4):445-459. Medline  DOI This review article evaluated the role of various factors associated with increased blood loss in TKA and THA. Published literature was reviewed to identify modifiable risk factors that increase the likelihood of perioperative blood loss. Preoperative anemia was identified as one of the strongest predictors of needing postoperative transfusion. 9. Ahmed I, Chan JK, Jenkins P, Brenkel I, Walmsley P: Estimating the transfusion risk following total knee arthroplasty. Orthopedics 2012;35(10):e1465-e1471. Medline  DOI This study was a retrospective review of a prospectively collected database of 2281 patients who underwent unilateral TKA in a district general hospital over a 10-year period. The goal of the study was to identify risk factors independently associated with the risk of requiring a blood transfusion following TKA. The authors recognized considerable variation in the transfusion practices among orthopaedic surgeons following elective TKA. Risk factors associated with postoperative blood transfusion were identified using predictive models based on the multiple regression analysis. 10. Holt JB, Miller BJ, Callaghan JJ, Clark CR, Willenborg MD, Noiseux NO: Minimizing blood transfusion in total hip and knee arthroplasty through a multimodal approach. J Arthroplasty 2016;31(2):378-382. Medline  DOI This prospective cohort study determined the effects of a multimodal, multidisciplinary approach of perioperative blood management on the rate of blood transfusions for 1,010 consecutive patients undergoing primary TKA (488) or THA (522). The protocol included preoperative hemoglobin optimization through a multidisciplinary approach, minimization of perioperative blood loss, and adherence to evidence-based transfusion guidelines. It was concluded that adoption of a multimodal blood management algorithm can significantly reduce blood transfusions in primary joint arthroplasty. 11. Bruce W, Campbell D, Daly D, Isbister J: Practical recommendations for patient blood management and the reduction of perioperative transfusion in joint replacement surgery. ANZ J Surg 2013;83(4):222-229. Medline  DOI

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

In this review article on perioperative blood management for patients undergoing TJA, data from the Australian Better Safer Transfusion program indicate that one-third of patients undergoing hip or knee arthroplasty receive perioperative blood transfusions. Practical management recommendations for perioperative bleeding in joint arthroplasty surgery were developed, based on available evidence and expert consensus opinion, to promote a new, responsible approach to transfusion management. A comprehensive blood management program was recommended for hemodynamically stable patients involving preoperative evaluation and optimization of patients’ medical health. 12. Parvizi J, Miller AG, Gandhi K: Multimodal pain management after total joint arthroplasty. J Bone Joint Surg Am 2011;93(11):1075-1084. Medline  DOI In this article, the authors reviewed various potential measures for pain management after TJA, and recommended multimodal pain management for optimal pain control with less reliance on opioids and fewer side effects. Based on recent reports, the authors recommend using the traditional and COX-2 NSAIDs. Nearly all multimodal pain management modalities have a safe side-effect profile when they are added to existing methods with the exception of drugs such as DepoDur. Adequate postoperative pain control after TJA allows faster rehabilitation. 13. Mont MA, Jacobs JJ, Boggio LN, et al; AAOS: Preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty. J Am Acad Orthop Surg 2011;19(12):768-776. Medline  DOI In this review article, the available literature concerning patient screening, risk factor assessment, and prophylactic treatment against venous thromboembolic disease by means of postoperative mobilization, neuraxial agents, and vena cava filters was evaluated. The purpose of this work was to recommend updated guidelines originally published in 2007 article on the same topic. The updated recommendations included further assessment of patients with a history of prior venous thromboembolism, known bleeding disorders such as hemophilia, and for the presence of active liver disease, and early mobilization for patients following elective hip and knee arthroplasty. 14. Cuenca J, García-Erce JA, Martínez F, Cardona R, Pérez-Serrano L, Muñoz M: Preoperative haematinics and transfusion protocol reduce the need for transfusion after total knee replacement. Int J Surg 2007;5(2):89-94. Medline  DOI 15. Cushner FD, Lee GC, Scuderi GR, Arsht SJ, Scott WN: Blood loss management in high-risk patients undergoing total knee arthroplasty: A comparison of two techniques. J Knee Surg 2006;19(4):249-253. Medline  DOI 16. Weber EW, Slappendel R, Hémon Y, et al: Effects of epoetin alfa on blood transfusions and postoperative recovery in orthopaedic surgery: The European Epoetin Alfa Surgery Trial (EEST). Eur J Anaesthesiol 2005;22(4):249-257. Medline  DOI

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Chapter 3: Blood Management

17. Levine BR, Haughom B, Strong B, Hellman M, Frank RM: Blood management strategies for total knee arthroplasty. J Am Acad Orthop Surg 2014;22(6):361-371. Medline  DOI A multimodal blood management protocol for patients undergoing TKA is discussed. Thorough patient evaluation is recommended to individualize blood management and conservation pathways to maximize efficacy and avoid associated complications. Evidence regarding various preoperative, intraoperative, and postoperative strategies of blood management to prevent the need for blood transfusion and the associated risks of clerical error, infection, and immunologic reactions is presented. 18. Bedair H, Yang J, Dwyer MK, McCarthy JC: Preoperative erythropoietin alpha reduces postoperative transfusions in THA and TKA but may not be cost-effective. Clin Orthop Relat Res 2015;473(2):590-596. Medline  DOI

19. Bezwada HR, Nazarian DG, Henry DH, Booth RE Jr, Mont MA: Blood management in total joint arthroplasty. Am J Orthop (Belle Mead NJ) 2006;35(10):458-464. Medline 20. Bou Monsef J, Figgie MP, Mayman D, Boettner F: Targeted preoperative autologous blood donation: A prospective study of two thousand and three hundred and fifty total hip arthroplasties. Int Orthop 2014;38(8):1591-1595. Medline  DOI

23. Lee GC, Hawes T, Cushner FD, Scott WN: Current trends in blood conservation in total knee arthroplasty. Clin Orthop Relat Res 2005;440:170-174. Medline  DOI 24. Goodnough LT, Despotis GJ, Merkel K, Monk TG: A randomized trial comparing acute normovolemic hemodilution and preoperative autologous blood donation in total hip arthroplasty. Transfusion 2000;40(9):1054-1057. Medline  DOI 25. Tai TW, Lin CJ, Jou IM, Chang CW, Lai KA, Yang CY: Tourniquet use in total knee arthroplasty: A meta-analysis. Knee Surg Sports Traumatol Arthrosc 2011;19(7):11211130. Medline  DOI In this meta-analysis of eight RCTs and three high-quality prospective studies involving 634 knees, clinical outcomes of TKA with and without tourniquet use were compared. The authors observed that tourniquet use could shorten the surgical time if released after wound closure; however, early release did not shorten the surgical time. It was concluded that using tourniquet in TKA may save time but may not reduce blood loss, and a tourniquet should be used with caution because of the higher risks of thromboembolic complications. 26. Huang ZY, Pei FX, Ma J, et al: Comparison of three different tourniquet application strategies for minimally invasive total knee arthroplasty: A prospective non-randomized clinical trial. Arch Orthop Trauma Surg 2014;134(4): 561-570. Medline  DOI In this nonrandomized prospective cohort study involving 90 patients, clinical outcomes were investigated in relation to the timing of tourniquet use--from incision to wound closure, from incision to after cement hardening, and only during cementing. Using a tourniquet only during cementing led to lower serum markers for inflammation and muscle damage, such as C-reactive protein, interleukin-6, creatine kinase and myoglobin; however, there was no difference in the clinical outcomes in Hospital for Special Surgery knee scores, ROM, estimated blood loss, swelling ratio, visual analog scale pain score, and length of hospital stay. It was concluded that using a tourniquet during the entire TKA surgery causes less intraoperative blood loss but more excessive inflammation and muscle damage. Part-time tourniquet use was associated with less inflammation and muscle damage but did not affect the early functional outcomes.

This prospective study involving 2,351 THA patients was designed to investigate the effectiveness of targeted PAD protocol on reducing transfusion rates in 2,350 unilateral primary THA procedures. The authors concluded that targeted PAD reduces the need for allogeneic blood transfusion in anemic patients and the number of transfusions compared to routine preoperative autologous donation.

27. Hernández-Castaños DM, Ponce VV, Gil F: Release of ischaemia prior to wound closure in total knee arthroplasty: A better method? Int Orthop 2008;32(5):635-638. Medline  DOI

21. Gandini G, Franchini M, Bertuzzo D, et al: Preoperative autologous blood donation by 1073 elderly patients undergoing elective surgery: A safe and effective practice. Transfusion 1999;39(2):174-178. Medline  DOI

28. Berry DJ, Bozic KJ: Current practice patterns in primary hip and knee arthroplasty among members of the American Association of Hip and Knee Surgeons. J Arthroplasty 2010;25(6suppl):2-4. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

The purpose of this single-blind prospective cohort study was to determine the efficacy of preoperative EPO in reducing postoperative transfusions in TKA and THA; whether patients treated with EPO had a reduced length of hospital stay or a different discharge disposition; and whether the use of EPO reduces overall blood management costs. The study involved a total of 80 patients who underwent primary THA or TKA with a preoperative hemoglobin less than 13 g/dL over a 10-month period and were recommended preoperative treatment with EPO. A total of 24 patients who received at least one dose of EPO were compared with 56 control patients in terms of transfusion frequency, length of hospital stay and discharge disposition, and overall blood management costs. None of the patients treated with preoperative EPO required transfusions and 23 of 56 patients (41%) who did not receive EPO needed to be transfused. It was concluded that EPO significantly reduced the need for postoperative transfusions in high-risk patients undergoing THA and TKA; however, it was not found to be cost effective. Level of evidence: III.

22. Pierson JL, Hannon TJ, Earles DR: A blood-conservation algorithm to reduce blood transfusions after total hip and knee arthroplasty. J Bone Joint Surg Am 2004;86A(7):1512-1518. Medline

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Section 1: Hip and Knee

A poll was conducted at the 2009 Annual Meeting of the American Association of Hip and Knee Surgeons to determine current practices among its members in primary THA and TKA. This article summarizes the audience responses to several multiple choice questions concerning perioperative management and surgical practice patterns and preferences. 29. Juelsgaard P, Larsen UT, Sørensen JV, Madsen F, Søballe K: Hypotensive epidural anesthesia in total knee replacement without tourniquet: Reduced blood loss and transfusion. Reg Anesth Pain Med 2001;26(2):105-110. Medline

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30. Eroglu A, Uzunlar H, Erciyes N: Comparison of hypotensive epidural anesthesia and hypotensive total intravenous anesthesia on intraoperative blood loss during total hip replacement. J Clin Anesth 2005;17(6):420-425. Medline  DOI 31. Suarez JC, Slotkin EM, Szubski CR, Barsoum WK, Patel PD: Prospective, randomized trial to evaluate efficacy of a bipolar sealer in direct anterior approach total hip arthroplasty. J Arthroplasty 2015;30(11):1953-1958. Medline  DOI In this prospective, double-blind RCT, the hemostatic efficacy of a bipolar sealer in direct anterior approach THA on surgical blood loss and transfusion requirements was investigated in 118 patients. The authors observed a lower transfusion rate in the treatment group (3.5% vs 16.4%, P = 0.03), and differences in hemoglobin level (P = 0.04), calculated blood loss (P = 0.02), and hidden blood loss (P = 0.02) favoring the treatment group. The authors concluded that the use of a bipolar sealer decreased intraoperative blood loss and transfusion requirements in THA via direct anterior approach. 32. Ackerman SJ, Tapia CI, Baik R, Pivec R, Mont MA: Use of a bipolar sealer in total hip arthroplasty: Medical resource use and costs using a hospital administrative database. Orthopedics 2014;37(5):e472-e481. Medline  DOI A retrospective, comparative cohort study was conducted using a nationwide all-payer hospital administrative database to assess medical resource use, associated costs, and the incidence of transfusion and complications among patients undergoing THA with or without the use of a bipolar sealer. The bipolar sealer group had higher supply costs, which were offset by reduced hospital inpatient room and board and operating room costs; there was no significant difference in total hospital costs between the two groups ($18,937 vs $18,734; P = 0.56). The authors concluded that a bipolar sealer decreases postoperative blood transfusions and length of hospital stay after primary THA without increasing total hospital costs. 33. Kamath AF, Austin DC, Derman PB, Clement RC, Garino JP, Lee GC: Saline-coupled bipolar sealing in simultaneous bilateral total knee arthroplasty. Clin Orthop Surg 2014;6(3):298-304. Medline  DOI In this study, clinical outcomes were investigated in 71 consecutive patients undergoing simultaneous bilateral TKA with the use of bipolar sealing or conventional electrocautery. The bipolar sealer and electrocautery groups

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

were matched for age, sex, BMI, American Society of Anesthesiologists classification, and preoperative hemoglobin. In comparison with the electrocautery group, the members of the bipolar sealer group were 35% less likely to require a transfusion, and had a significantly lower median number of transfusions per case. However, the hemoglobin change, the total blood loss, and the length of hospital stay were not significantly different between the groups. The experimental group had longer surgical times. It was concluded that bipolar sealing could be a good blood loss reduction tool in simultaneous bilateral TKA; however, the marginal savings attributed to reduced transfusion rates with use of the bipolar sealer did not exceed the additional per-case expense of using the device. 34. Clement RC, Kamath AF, Derman PB, Garino JP, Lee GC: Bipolar sealing in revision total hip arthroplasty for infection: Efficacy and cost analysis. J Arthroplasty 2012;27(7):1376-1381. Medline  DOI This case-matched study of 76 consecutive revision THAs for infection included an experimental bipolar sealing group and a control group of conventional electrocautery. Groups were matched for sex, BMI, American Society of Anesthesiologists classification, and surgery type. Total blood loss, intraoperative blood loss, and perioperative hemoglobin drop were significantly less, and the surgical time was significantly shorter in the experimental group, which translated into gross savings approximately equal to the cost of the device. The authors concluded that the decreases in total blood loss and perioperative hemoglobin decline, along with financial savings, may support the use of bipolar sealing in infected revision THA. 35. Derman PB, Kamath AF, Lee GC: Saline-coupled bipolar sealing in revision total knee arthroplasty for infection. Am J Orthop (Belle Mead NJ) 2013;42(9):407-411. Medline This single-surgeon, case-control study was designed to evaluate if the choice of an electrocautery device affected total blood loss, transfusion requirements, and total cost in revision TKA for infection. The study involved 80 patients with infected TKA (test group) who underwent revision surgery that involved the use of a saline-coupled bipolar sealing device. Results were compared with those of 40 patients (control group) who underwent similar surgery without the use of a bipolar sealing device, and were matched for age, BMI, and American Society of Anesthesiologists classification. No statistical differences were found between the test and control groups in terms of blood loss or transfusion requirements. However, the surgical time was significantly lower and the average net additional cost was about $70 per case in the bipolar sealer group. The authors concluded that the use of a saline-­coupled bipolar sealing device in patients with infected TKAs is not clinically or economically justified. 36. Yang TQ, Geng XL, Ding MC, Yang MX, Zhang Q: The efficacy of fibrin sealant in knee surgery: A meta-analysis. Orthop Traumatol Surg Res 2015;101(3):331-339. Medline  DOI In this meta-analysis of 9 RCTs and 4 prospective comparative trials involving a total of 1,299 patients, the use

© 2017 American Academy of Orthopaedic Surgeons

Chapter 3: Blood Management

of fibrin sealant was associated with a decrease in hemoglobin reduction, transfusion rate, number of transfusion units, and hospital stay as well as the incidence of complications. It was concluded that high-dose fibrin sealant may be beneficial during knee surgery; however, the effects of a low dose of fibrin during knee surgery remain inconclusive. 37. Wang H, Shan L, Zeng H, Sun M, Hua Y, Cai Z: Is fibrin sealant effective and safe in total knee arthroplasty? A meta-analysis of randomized trials. J Orthop Surg Res 2014;9:36. Medline  DOI

38. Randelli F, D’Anchise R, Ragone V, Serrao L, Cabitza P, Randelli P: Is the newest fibrin sealant an effective strategy to reduce blood loss after total knee arthroplasty? A randomized controlled study. J Arthroplasty 2014;29(8):1516-1520. Medline  DOI In this prospective RCT, 62 patients who underwent primary TKA were categorized according to the topical use of a fibrin sealant (Evicel) into a sealant group (n = 31) and a control group (n = 31). Topical application of a fibrin sealant resulted in a mean total blood loss of 1.8 L as compared to 1.9 L in the control group (n = 31), and a transfusion rate of 25.8% in the sealant group vs 32.3% in the control group The transfusion rate decreased linearly with increasing preoperative hemoglobin levels in the treatment group. It was concluded that topical application of a fibrin sealant did not reduce perioperative blood loss and the need for allogeneic blood transfusion. 39. Maheshwari AV, Korshunov Y, Naziri Q, Pivec R, Mont MA, Rasquinha VJ: No additional benefit with use of a fibrin sealant to decrease peri-operative blood loss during primary total knee arthroplasty. J Arthroplasty 2014;29(11):2109-2112. Medline  DOI This is a retrospective study involving chart review of 113 consecutive patients who underwent primary TKA with the use of a fibrin sealant and 70 patients without the use of a fibrin sealant. The authors found no significant difference in hemoglobin levels up to 3 days after surgery. There was no difference in the intraoperative or postoperative or total perioperative blood loss. The authors concluded that fibrin sealant offered no additional benefit regarding perioperative blood loss associated with TKA, and ceased using the product based on the study findings. 40. Kim C, Park SS, Davey JR: Tranexamic acid for the prevention and management of orthopedic surgical hemorrhage: Current evidence. J Blood Med 2015;6:239-244. Medline

© 2017 American Academy of Orthopaedic Surgeons

41. Tengborn L, Blombäck M, Berntorp E: Tranexamic acid—an old drug still going strong and making a revival. Thromb Res 2015;135(2):231-242. Medline  DOI Historical perspective and clinical information regarding the use of TXA in different surgical subspecialties are presented in this review. Indications, contraindications, pharmacology, routes of administration, drug-drug interactions, safety profile, and current trends in the use of TXA are presented.

1: Hip and Knee

The objective of this meta-analysis study of 8 RCTs involving 641 patients was to evaluate the efficacy and safety of fibrin sealant in patients following TKA. The authors observed that the use of fibrin sealant significantly reduced postoperative drainage and blood transfusions and led to a significant improvement in the postoperative ROM. However, the use of a fibrin sealant did not significantly reduce the total blood loss. No significant differences were observed in any adverse events including fever, infection, or hematoma among the study groups. The use of fibrin sealant was determined to be effective and safe as a hemostatic therapy for patients with TKA.

This is a review article based on nine past studies aimed at evaluating and presenting evidence regarding current practices regarding the use of TXA in THA and TKA procedures. The authors provided this comprehensive review regarding various aspects of TXA use in the recent past including its pharmacology, intravenous versus intra-­ articular routes of administration, drug-drug interactions, safety profile, current trends in the use of TXA in THA and TKA procedures.

42. Serrano Mateo L, Goudarz Mehdikhani K, Cáceres L, Lee YY, Gonzalez Della Valle A: Topical tranexamic acid may improve early functional outcomes of primary total knee arthroplasty. J Arthroplasty 2016; Jan. 21 (Epub ahead of print]. Medline  DOI In this retrospective review, clinical outcomes during the first 4 postoperative months after TKA were investigated in 166 consecutive patients (TXA group, 179 TKA procedures) who received 3 g topical TXA before tourniquet deflation, and compared with those in 197 consecutive patients (control group, 209 TKA procedures) in whom TXA was not used. Compared to the control group, the TXA group had significantly higher hemoglobin on postoperative day 1, day 2, and at discharge, and a lower blood transfusion rate (5% vs 22%). The clinical benefit of topical TXA administration extends beyond the hospitalization period, with improved knee function during the first 6 postoperative weeks. 43. Good L, Peterson E, Lisander B: Tranexamic acid decreases external blood loss but not hidden blood loss in total knee replacement. Br J Anaesth 2003;90(5):596-599. Medline  DOI 44. Wong J, Abrishami A, El Beheiry H, et al: Topical application of tranexamic acid reduces postoperative blood loss in total knee arthroplasty: A randomized, controlled trial. J Bone Joint Surg Am 2010;92(15):2503-2513. Medline  DOI This prospective, double-blind placebo-controlled trial was designed to assess the efficacy and safety of the topical application of TXA on postoperative blood loss in patients undergoing primary unilateral cemented TKA. It was concluded that topical application of TXA directly into the surgical wound reduced postoperative bleeding by 20% to 25%, or 300 to 400 mL, resulting in 16% to 17% higher postoperative hemoglobin levels compared with placebo, with no clinically important increase in complications such as deep vein thrombosis or pulmonary embolism. 45. Gao F, Sun W, Guo W, Li Z, Wang W, Cheng L: Topical application of tranexamic acid plus diluted epinephrine

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Section 1: Hip and Knee

reduces postoperative hidden blood loss in total hip arthroplasty. J Arthroplasty 2015;30(12):2196-2200. Medline  DOI

49. Springer BD, Odum SM, Fehring TK: What is the benefit of tranexamic acid vs reinfusion drains in total joint arthroplasty? J Arthroplasty 2016;31(1):76-80. Medline  DOI

In a RCT involving 107 patients undergoing THA, patients were randomized into two groups: 53 received intra-­ articular TXA 3 g plus 1:200,000 diluted epinephrine 0.25 mg; 54 received topical TXA 3 g alone. It was observed that combined administration of TXA and diluted epinephrine significantly reduced total blood loss, hidden blood loss, and transfusion rate as compared with TXA alone, without increasing the risks of thromboembolic and hemodynamic complications.

In this RCT, the efficacy and cost of TXA and standard and reinfusion drains were compared in 186 primary TJAs (71 hips, 115 knees). The authors observed a significant decrease in hemoglobin level in the TXA group compared with standard drains and reinfusion drains; however, there was no significant difference in transfusion rates. The unit cost of the reinfusion system ($581.89) was substantially higher than the standard drain ($7.56) and TXA ($35.91 per gram). TXA was determined to be more efficacious and less expensive than reinfusion drains as a blood management tool for TJA.

1: Hip and Knee

46. Gao F, Sun W, Guo W, Li Z, Wang W, Cheng L: Topical administration of tranexamic acid plus diluted-epinephrine in primary total knee arthroplasty: A randomized double-blinded controlled trial. J Arthroplasty 2015;30(8):1354-1358. Medline  DOI In this RCT, the efficacy of TXA plus diluted epinephrine was evaluated in primary unilateral TKA without drainage. One hundred patients scheduled to undergo TKA were randomized into two groups: 50 patients received intra-articular 3 g TXA plus 0.25 mg diluted epinephrine (1:200,000), and 50 patients received 3 g topical TXA alone. Topical combined administration of TXA and diluted epinephrine significantly reduced total blood loss, hidden blood loss, and transfusion rate without increasing the risk of thromboembolic and hemodynamic complications.

50. Koyano G, Jinno T, Koga D, Hoshino C, Muneta T, Okawa A: Is closed suction drainage effective in early recovery of hip joint function? Comparative evaluation in one-stage bilateral total hip arthroplasty. J Arthroplasty 2015;30(1):74-78. Medline  DOI In this prospective study, single-stage primary bilateral noncemented THA with unilateral closed suction drainage (CSD) was performed for 51 patients (102 hips) and the local effects of CSD were quantitatively evaluated after surgery. CSD for hip arthroplasty was found to be advantageous in reducing postoperative local inflammation and can be recommended to facilitate postoperative pain relief and early recovery of hip joint function.

47. Melvin JS, Stryker LS, Sierra RJ: Tranexamic acid in hip and knee arthroplasty. J Am Acad Orthop Surg 2015;23(12):732-740. Medline  DOI

51. Bjerke-Kroll BT, Sculco PK, McLawhorn AS, Christ AB, Gladnick BP, Mayman DJ: The increased total cost associated with post-operative drains in total hip and knee arthroplasty. J Arthroplasty 2014;29(5):895-899. This study provided comprehensive evidence in high-­ Medline  DOI quality studies regarding clinical efficacy of TXA. TXA, both topical and intravenous administration, has been In a consecutive series of 536 unilateral primary THAs and effective in decreasing perioperative blood loss and trans598 unilateral primary TKAs, the use of a postoperative fusion requirements in both primary and revision hip and drain was associated with $538 additional cost per THA, knee arthroplasty. It is recommended that an initial intraand $455 for TKA. The use of a drain increased hospital length of stay for THA, but not for TKA. In both groups, venous dose be given before the procedure, with at least the use of a drain increased estimated blood loss and inone additional intravenous postoperative dose. Topical TXA doses of 2 g or more appear to be more effective creased the amount of allogeneic blood transfused. Drain than lower doses. Few adverse reactions have been reuse was associated with a total cost of $432,972 over a 10-week period. A selective approach to the use of drains ported in arthroplasty patients, and no study to date has in primary joint arthroplasties is favored. demonstrated an increased risk of symptomatic venous thromboembolic events in these patients. 52. Wang CG, Sun ZH, Liu J, Cao JG, Li ZJ: Safety and 48. Phan DL, Ani F, Schwarzkopf R: Cost analysis of efficacy of intra-articular tranexamic acid injection tranexamic acid in anemic total joint arthroplasty patients. without drainage on blood loss in total knee arthroplasJ Arthroplasty 2016;31(3):579-582. Medline  DOI ty: A randomized clinical trial. Int J Surg 2015;20:1-7. Medline  DOI The material and administration costs of TXA and packed red blood cells were compared with those of the standard This double-blind randomized placebo-control trial intreatment of preoperative anemia using iron supplemenvolved 60 patients who underwent primary unilateral tation (FE) and EPO. Approximately 18.5% (45/243) pacemented TKA. The subjects were randomized into a tients had preoperative anemia. The cost of the treatment TXA group (30 knees received 500 mg intra-articular of preoperative anemia with FE or EPO without a postopinjection without drainage) and a control group (30 knees erative packed red blood cells ranged from 2 to 17 times received saline intra-articular injection. As compared with more than treatment with TXA. TXA was determined the control group, the TXA group had less of a decrease in hemoglobin level at postoperative day 3 (9.10 vs 10.51 to be significantly less expensive than FE or EPO as a g/dL), and significantly less mean blood loss at postoptreatment option for patients with TJA presenting with erative day 5 (1,000 vs 1,560 mL). The TXA group had preoperative anemia, and it serves as a cost-effective adjunct for limiting transfusion rates. lower D-dimer levels at days 3 and 5 after TKA. The

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© 2017 American Academy of Orthopaedic Surgeons

Chapter 3: Blood Management

TXA group also had significantly greater red blood cell mass and hematocrit, and lower transfusion rates and average amount transfused blood than the control group. No significant differences were observed in the coagulation markers, rates of symptomatic deep vein thrombosis, pulmonary embolism, or wound healing problems. The authors concluded that TXA treatment without drainage during TKA reduces the blood transfusions requirement without increasing the rate of adverse events. 53. Watanabe T, Muneta T, Yagishita K, Hara K, Koga H, Sekiya I: Closed suction drainage is not necessary for total knee arthroplasty: A prospective study on simultaneous bilateral surgeries of a mean follow-up of 5.5 years. J Arthroplasty 2016;31(3):641-645. Medline  DOI

One hundred fifteen patients undergoing TKA were randomly allocated to an autotransfusion drain or no-­ drainage system. In the autotransfusion group, retransfusion of 515 mL (0-1,500 mL) of drained blood was done within the first 6 hours after surgery. Compared with the no-drainage group, the autotransfusion group had significantly higher hemoglobin levels on postoperative day 1 (11.6 vs 11.0 g/dL), day 2 (11.0 vs 10.3 g/dL) and day 3 (10.5 vs 9.8 g/dL), and lower total perioperative net blood loss (1,576 mL vs 1,837 mL) and allogeneic transfusion rates (10.2% vs 19.6%). There were no differences in pain scores, ROM, or adverse events during hospital stay and the first 3 months after surgery. The authors concluded that the use of a postoperative autologous blood retransfusion drainage system following TKA results in higher hemoglobin levels after surgery and less total blood loss than no drainage. 57. So-Osman C, Nelissen RG, Koopman-van Gemert AW, et al: Patient blood management in elective total hip- and knee-replacement surgery (part 2): A randomized controlled trial on blood salvage as transfusion alternative using a restrictive transfusion policy in patients with a preoperative hemoglobin above 13 g/dl. Anesthesiology 2014;120(4):852-860. Medline  DOI

This systematic review and meta-analysis of six RCTs was conducted to investigate the effect of postoperative suction drainage on clinical outcomes in TKA patients. No significant difference was seen between the individuals who received a drain and those who did not in terms of knee ROM, reduction in swelling, length of hospital stay and postoperative hemoglobin level. The authors concluded that closed suction drains are possibly not required following TKA.

In this prospective randomized study on the integrated use of erythropoietin, cell saver, and/or postoperative drain reinfusion devices (DRAIN), 1,759 patients undergoing THA or TKA were randomized between autologous reinfusion by cell saver or DRAIN or no blood salvage device. The authors observed no difference in erythrocyte use between cell saver and DRAIN groups. The transfusion rate was 7.7% in patients in the autologous group compared with 8.3% in patients in the control group while applying a restrictive transfusion threshold. Blood salvage increased the per-patient costs by €298. The authors concluded that autologous intra- and postoperative blood salvage devices were not effective as transfusion alternatives especially in patients with preoperative hemoglobin levels greater than 13 g/dl.

55. Zhou XD, Li J, Xiong Y, Jiang LF, Li WJ, Wu LD: Do we really need closed-suction drainage in total hip arthroplasty? A meta-analysis. Int Orthop 2013;37(11):2109-2118. Medline  DOI

58. van Bodegom-Vos L, Voorn VM, So-Osman C, et al: Cell salvage in hip and knee arthroplasty: A meta-analysis of randomized controlled trials. J Bone Joint Surg Am 2015;97(12):1012-1021. Medline  DOI

This meta-analysis study of 20 RCTs involving 3,186 patients investigated whether closed-suction drainage is safe and effective in promoting wound healing and reducing blood loss and other complications compared with no drainage in THA. No significant difference was observed in the incidence of infection, blood loss, changes in hemoglobin and hematocrit, functional assessment, or other complications when the drainage group was compared with the no-drainage group. It was concluded that the routine use of closed-suction drainage for elective THA may not be beneficial.

In the meta-analysis of 43 trials (5,631 patients), cell salvage reduced the exposure to allogeneic RBC transfusion in THA (risk ratio 0.66) and TKA (risk ratio, 0.51). However, the authors observed that unlike the findings in the studies earlier than 2010, cell salvage did not reduce either the exposure rate or the volume of transfused RBCs in THA and TKA patients in more recently published trials (2010 to 2012). The authors attributed this discrepancy to the changes in blood transfusion management practice.

54. Quinn M, Bowe A, Galvin R, Dawson P, O’Byrne J: The use of postoperative suction drainage in total knee arthroplasty: A systematic review. Int Orthop 2015;39(4): 653-658. Medline  DOI

56. Horstmann W, Kuipers B, Ohanis D, Slappendel R, Kollen B, Verheyen C: Autologous re-transfusion drain compared with no drain in total knee arthroplasty: A

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

In this prospective study, 63 patients (126 knees) who underwent bilateral simultaneous TKA using a cemented posterior stabilized prosthesis were classified into 3 groups based on the use of a suction drain – a bilateral closed suction drain group (20 patients), a unilateral closed suction drain group (22 patients), and a no-drain group (21 patients). After short- and long-term clinical outcomes were evaluated, it was determined that there were no significant differences in incidence of short-term or long-term complications, knee ROM, or circumference between the knees with drainage and those without drainage. Therefore, closed suction drainage was deemed unnecessary after TKA using cemented posterior-stabilized prostheses.

randomised controlled trial. Blood Transfus 2014;12(suppl 1):s176-s181. Medline

59. Xie J, Feng X, Ma J, et al: Is postoperative cell salvage necessary in total hip or knee replacement? A meta-analysis of randomized controlled trials. Int J Surg 2015;21:135-144. Medline  DOI

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In this meta-analysis involving 19 RCTs (3,482 patients), postoperative cell salvage significantly reduced the allogeneic blood transfusion requirement after TKA (risk ratio = 0.46) and THA (risk ratio = 0.46), and resulted in a greater postoperative hemoglobin level. No significant differences were noted regarding length of hospital stay, incidence of febrile reaction, wound infection, and deep vein thrombosis. 60. Klein HG: How safe is blood, really? Biologicals 2010;38(1):100-104. Medline  DOI Updated information regarding safety issues and potential risks and complications associated with blood transfusion is presented. Although current blood transfusion practices are safe, they do not come without risk.

1: Hip and Knee

61. American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies: Practice guidelines for perioperative blood transfusion and adjuvant therapies: An updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies. Anesthesiology 2006;105(1):198-208. Medline  DOI This update includes data published since the “Practice Guidelines for Blood Component Therapy” were adopted by the American Society of Anesthesiologists (ASA) in 1995. The authors provided practical preoperative, intraoperative, and postoperative guidelines regarding detection and treatment of anemia, blood conservation, and transfusion. 62. Carson JL, Grossman BJ, Kleinman S, et al; Clinical Transfusion Medicine Committee of the AABB: Red blood cell transfusion: A clinical practice guideline from the AABB*. Ann Intern Med 2012;157(1):49-58. Medline  DOI This article presents guidelines formulated by the AABB based on a systematic review of RCTs regarding transfusion thresholds published from 1950 to 2011. The authors discussed the clinical consequences of restrictive transfusion strategies in terms of overall mortality, nonfatal myocardial infarction, cardiac events, pulmonary edema, stroke, thromboembolism, renal failure, infection, hemorrhage, mental confusion, functional recovery, and length of hospital stay. According to the AABB, a restrictive transfusion strategy (7 to 8 g/dL) is recommended in hospitalized, stable patients, even with preexisting cardiovascular disease and to consider transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less. 63. Loftus TJ, Spratling L, Stone BA, Xiao L, Jacofsky DJ: A patient blood management program in prosthetic joint arthroplasty decreases blood use and improves outcomes. J Arthroplasty 2016;31(1):11-14. Medline  DOI The authors studied whether a patient blood management program for patients undergoing THA or TKA would result in a decrease in the percentage of transfused packed red blood cells and improve outcomes. This retrospective cohort study included 12,590 patients and demonstrated a 44% decrease in the percentage of patients transfused, which was associated with a significant reduction in

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complications, 30-day readmissions and hospital length of stay. 64. Bagsby DT, Samujh CA, Vissing JL, Empson JA, Pomeroy DL, Malkani AL: Tranexamic acid decreases incidence of blood transfusion in simultaneous bilateral total knee arthroplasty. J Arthroplasty 2015;30(12):2106-2109. Medline  DOI The goal of this retrospective review involving 103 patients undergoing simultaneous bilateral TKA (46 TXA group and 57 controls) was to examine if administration of TXA would decrease blood loss and requirement for allogeneic blood transfusion. The authors observed significantly higher hemoglobin levels (4.33 vs 2.95) and lower transfusion incidence (17.4% vs 57.9%) in patients who received TXA on the postoperative day 1 than those who did not. The authors concluded that TXA was effective in reducing the transfusion rates by almost 70% in simultaneous bilateral TKA. 65. Samujh C, Falls TD, Wessel R, Smith L, Malkani AL: Decreased blood transfusion following revision total knee arthroplasty using tranexamic acid. J Arthroplasty 2014;29(9suppl):182-185. Medline  DOI The goal of this retrospective review was to examine the efficacy of TXA in patients undergoing revision TKA. Of 111 patients, 43 patients (TXA group) who received a single intravenous TXA dose of 10 mg/kg required fewer transfusions as compared to the 68 patients (controls) who did not receive TXA. When stratified by type of revision, patients undergoing femoral and tibial component revision had lower transfusion rates than control patients. Given the drawbacks of allogeneic blood transfusion, the authors recommended the use of TXA in revision TKA, especially when both components are being revised. 66. Perfetti DC, Boylan MR, Naziri Q, Khanuja HS, Urban WP: Does sickle cell disease increase risk of adverse outcomes following total hip and knee arthroplasty? A nationwide database study. J Arthroplasty 2015;30(4):547-551. Medline  DOI The authors used the Nationwide Inpatient Sample to identify all THA and TKA admissions between 1998 and 2010, and investigated the associated complications and comorbidities in patients with sickle cell disease who undergo THA or TKA procedures. After controlling for patient age, sex, insurance, race, and comorbidities, the risk of complications among admissions with sickle cell disease was 152% higher for THA and 137% higher for TKA, and the length of hospital stay was 42% and 20% longer for THA and TKA procedures, respectively. It was suggested that potential THA and TKA candidates with sickle cell disease be informed before admission of these risks. 67. Howard J, Malfroy M, Llewelyn C, et al: The Transfusion Alternatives Preoperatively in Sickle Cell Disease (TAPS) study: A randomised, controlled, multicentre clinical trial. Lancet 2013;381(9870):930-938. Medline  DOI This multicenter RCT was designed to evaluate if preoperative blood transfusions are beneficial to avoiding

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Chapter 3: Blood Management

complications in patients with sickle cell disease (hemoglobin SS or Sβ(0) thalassemia subtype) undergoing various surgical procedures including joint arthroplasty. Patients were randomly assigned to no transfusion or transfusion within 10 days before surgery, and the analysis was based on an intention-to-treat basis. A total of 13 of 33 patients (39%) in the no-transfusion group had clinically important complications within 30 days after surgery compared with 5 of 34 patients (15%) in the transfusion group. The unadjusted odds ratio of clinically important complications was 3.8, whereas the duration of hospital stay and readmission rates did not differ between study groups. It was concluded that preoperative transfusion was associated with decreased perioperative complications in patients with sickle cell disease, especially hemoglobin

SS subtype, who are scheduled to undergo low-risk and medium-risk surgeries. 68. Issa K, Banerjee S, Rifai A, et al: Blood management strategies in primary and revision total knee arthroplasty for Jehovah’s Witness patients. J Knee Surg 2013;26(6): 401-404. Medline  DOI An overview of various potential preoperative, intraoperative, and postoperative blood management measures that may be used for the care of Jehovah’s Witnesses who undergo knee arthroplasty procedures is presented. Reported outcomes of primary and revision TKA in these patients are reviewed. Because Jehovah’s Witnesses usually refuse blood transfusions because of their religious beliefs, this may create clinical or ethical challenges for the treating physicians. 1: Hip and Knee

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Chapter 4

Osteonecrosis of the Hip and Knee Nirav K. Patel, MD, FRCS  Jaydev B. Mistry, MD  Randa K. Elmallah, MD  Morad Chughtai, MD  James Nace, DO, MPT  Michael A. Mont, MD

Abstract

Keywords: osteonecrosis; hip; knee; collapse; management

Introduction Osteonecrosis is a condition with debilitating results that can cause structural collapse in the joints affected.

Dr. Nace or an immediate family member serves as a paid consultant to InforMD and has received research or institutional support from Stryker. Dr. Mont or an immediate family member has received royalties from Microport and Stryker; serves as a paid consultant to DJ Orthopaedics, Johnson & Johnson, Merz, Orthosensor, Pacira, Sage Products, Stryker, TissueGene, and US Medical Innovations; has received research or institutional support from DJ Orthopaedics, Johnson & Johnson, the National Institutes of Health (NIAMS & NICHD), Ongoing Care Solutions, Orthosensor, Stryker, and Tissue Gene; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this article/chapter: Dr. Patel, Dr. Mistry, Dr. Elmallah, and Dr. Chughtai.

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

Osteonecrosis is a debilitating condition that can result in structural collapse. It most commonly affects the femoral head, followed by the knee and shoulder joints. Although osteonecrosis of the hip and knee can be treated nonsurgically, the disease often progresses, which inevitably requires surgical intervention. The surgeon treating osteonecrosis of the hip and knee joint should understand the etiology, diagnosis, and management of the disease.

Osteonecrosis most commonly occurs in the femoral head, with an incidence of 10,000 to 20,000 new cases annually in the United States, which is expected to continue to increase.1,2 Osteonecrosis is seen more commonly in males and typically presents in patients 35 to 50 years of age.3 The knee is the second most common location of osteonecrosis, comprising 10% of all cases, and most frequently the distal femur is affected.4 Treatment options can vary depending on the stage of disease at presentation. In the early stage of osteonecrosis, there is little or no structural collapse and prognosis is often better than in advanced stages of disease. Occasionally, patients with early, or precollapse, disease can be treated nonsurgically, particularly if asymptomatic; however, surgery is often indicated. In osteonecrosis of the hip, almost 80% of cases are bilateral, and the eventual joint destruction and loss of function comprise 10% of all total hip arthroplasties (THAs).5 Advanced cases of knee osteonecrosis comprise 2% of all total knee arthroplasties (TKAs).6 Therefore, it is important for orthopaedic surgeons to be comfortable with managing osteonecrosis of both the hip and knee. Understanding the etiology and pathology, evaluation and diagnosis, and treatment (surgical and nonsurgical modalities) all help the surgeon managing osteonecrosis of the hip and knee. Osteonecrosis of the Hip Etiology and Pathogenesis Despite much research, the etiology of osteonecrosis is not well characterized, although many risk factors have been identified (Table 1). The process common with all etiologies is circulatory obstruction, the causes of which include coagulation of intraosseous circulation, venous thrombosis, and retrograde arterial occlusion. Intraosseous pressure increases, causing femoral head ischemia and eventual osteonecrosis. Even when a repair process is initiated, subchondral fracture and collapse are almost always inevitable. Osteonecrosis does not develop in all patients with risk factors, suggesting some genetic predisposition.

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Section 1: Hip and Knee

Table 1

1: Hip and Knee

Risk Factors for the Development of Osteonecrosis Direct Risk Factors

Indirect Risk Factors

Trauma: fracture or dislocation

Corticosteroids

Sickle cell disease

Alcohol abuse

HIV infection

Tobacco use

Chemotherapy

Systemic lupus erythematosus

Radiation

Organ transplantation

Myeloproliferative disorders

Renal failure

Gaucher disease

Coagulation abnormalities Pregnancy Genetic factors Caisson disease

Data from Mont MA, Cherian JJ, Sierra RJ, Jones LC, Lieberman JR: Nontraumatic osteonecrosis of the femoral head: Where do we stand today? A ten-year update. J Bone Joint Surg Am 2015;97[19]:16041627.

Trauma Hip dislocation and femoral head/neck fractures interrupt the medial circumflex artery, which is the main blood supply to the femoral head. Hip dislocation, which can cause osteonecrosis in 5% to 40% of patients, increases with the degree of initial displacement, and possibly with time to reduction (greater than 6 hours).7 The rate of osteonecrosis following femoral head fracture (usually with hip dislocation) ranges from 1% to 50%, depending on the location of an associated acetabular fracture and increasing with the Pipkin classification type (commonly used for uncommon femoral head fractures associated with hip dislocations [four types]). The rate of osteonecrosis for femoral neck fracture is as high as 10% in nondisplaced injuries and 30% in displaced injuries, increasing with the Garden classification type (for femoral neck fractures; can help predict risk of osteonecrosis [four types]). The risk of osteonecrosis can be reduced with prompt anatomic reduction and surgical fixation. Less commonly, cervicotrochanteric and intertrochanteric fractures can cause osteonecrosis.7 Corticosteroids High-dose corticosteroid use is a well-known risk factor for osteonecrosis, with rates of 3% to 23% seen in patients following transplantation.8,9 The available data

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are inconsistent in explaining the relationship between osteonecrosis and dosage, route, or treatment; however, several studies have shown the cumulative dose to be an important factor.9,10 In bone marrow stromal cells, corticosteroids cause cell apoptosis and a decrease in precursor cell proliferation, altering bone homeostasis and causing cellular injury.11 In addition, corticosteroids can impair blood flow by enhancing femoral head arterial constriction, as seen with 24 hours of methylprednisolone treatment.12 Moreover, corticosteroids can activate proinflammatory pathways and are linked to various gene alterations (for example, interleukin (IL)-23, IL-1α, transforming growth factor-beta, IL-10 and tumor necrosis factor-alpha).13 These pathways also include decreased expression of bone marker genes and increased expression of adipogenic gene 422 (aP2) when bone marrow stromal cells are exposed to dexamethasone in culture. Corticosteroids can also induce extravascular fat deposition, adipocyte hypertrophy, and oxidative stress, suggesting a multifactorial pathophysiology.13 Alcohol Abuse Alcohol abuse is also a well-known risk factor for osteonecrosis of the hip with a clear dose-response relationship.14 Suspected causes of osteonecrosis of the hip and knee include impaired mesenchymal cell differentiation, impaired blood flow, and direct cellular toxicity. Alcohol reduces osteogenic differentiation and increases adipogenic cell differentiation, thus increasing adipogenic volume in the femoral head and altering blood flow. This has been shown in studies of mesenchymal stem cells (MSCs) retrieved from proximal femora bone marrow from alcoholics with osteonecrosis, which have demonstrated reduced osteogenic gene expression when cultured with alcohol.15 Many of the mechanisms are similar to those of corticosteroids, including cell apoptosis and possibly lipopolysaccharide interactions, which activate proinflammatory pathways. Coagulation Disorders Coagulation disorders, including inherited thrombophilia and hypofibrinolysis, are risk factors for blood flow interruption.16 In addition, endothelial progenitor cells required for angiogenesis can become dysfunctional.11 A study examined 200 patients with sickle cell disease at 15-year follow-up and reported that the incidence of osteonecrosis was 43% in the SS genotype, 38% in the SC genotype, and 19% in the Sβ+ thalassemia genotype.17 Hypofibrinolysis from familial high plasminogen activator inhibition was associated with osteonecrosis, and these patients were more likely to carry a hypofibrinolytic 4G polymorphism of the

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Chapter 4: Osteonecrosis of the Hip and Knee

plasminogen activator inhibitor-1 gene compared with control patients.16 Autoimmune Disease Osteonecrosis has been linked with various conditions such as systemic lupus erythematosus (SLE), Behçet disease, and rheumatoid arthritis. SLE has been shown to be an independent risk factor for osteonecrosis, especially in the presence of Raynaud phenomenon, hyperlipidemia, and raised anticardiolipin/antiphospholipid antibodies. Corticosteroid use in patients with SLE has a significantly higher risk of osteonecrosis compared with nonusers (37% versus 21%).18

Patients may be asymptomatic, but those who present with pain often report deep, throbbing anterior hip and thigh pain with insidious onset. A history of antecedent trauma may not always be present. The pain is worse with activity, with weight bearing, and at night. The presence of risk factors should always be explored (Table 1). In the early stages of osteonecrosis, physical examination can be unremarkable. Specific joint examination can show an antalgic gait and a positive Trendelenburg sign because of pain. The leg may be held in a position of maximal comfort, with a possible limb-length discrepancy (secondary to collapse) and surgical scars. Range of motion is preserved, but is generally painful at the groin. Imaging

Initially, plain radiographs including AP and frog-lateral views, are required, particularly for staging. The findings on these views are often normal, unless osteonecrosis has progressed enough to show subchondral collapse, acetabular involvement, and secondary osteoarthritis (Figure 1). Radiographs can also demonstrate radiolucencies and opacities. MRI has at least 99% sensitivity and specificity, and therefore is the gold standard for evaluating osteonecrosis of the femoral head. MRI is particularly useful in detecting precollapse lesions that can occur without subchondral fracture19 (Figure 2). Additionally, MRI helps with diagnosis, lesion sizing, and disease staging. Bone marrow edema also can be detected on MRI, and has been shown to correlate with the presence of hip pain and disease progression in 61 asymptomatic or minimally symptomatic hips at 60-month follow-up.20 If radiographs are normal or unclear, CT also can detect subchondral collapse. Bone scans have a high false-negative rate, and positron emission tomography scan, which is expensive and less commonly available, is sensitive but not specific, making these modalities less useful.19

© 2017 American Academy of Orthopaedic Surgeons

Figure 1

Radiographs of a left hip demonstrate femoral head collapse. A, AP view shows a subchondral fracture (crescent sign) and precollapse lesion of the femoral head (arrows). B, AP view shows a postcollapse lesion of the femoral head (circle). (Reproduced with permission from Mont MA, Cherian JJ, Sierra RJ, Jones LC, Lieberman JR: Nontraumatic osteonecrosis of the femoral head: Where do we stand today? A ten-year update. J Bone Joint Surg Am 2015;97[19]:1604-1627.)

1: Hip and Knee

Evaluation and Diagnosis

Staging

Disease staging helps to determine prognosis and plan treatment options for osteonecrosis. Various staging systems use radiologic features to stage osteonecrosis. The most frequently used system is Ficat and Arlet, which includes four stages that range from normal radiographic findings (stage 1) to femoral head collapse and acetabular involvement (stage 4). Other commonly used classification systems are the Association Research Circulation Osseous system, the Japanese Orthopaedic Association system, and the University of Pennsylvania system (Table 2). The four radiographic factors that are useful in evaluation are stage (before/after collapse), lesion size, amount of femoral head depression, and acetabular involvement.21 Increased lesion size specifically correlates with poorer prognosis. The Kerboul classification22 can help delineate prognosis and disease progression by using the combined necrotic angle, which is defined as the sum of the angles subtended by the necrotic segment in both midcoronal and midsagittal MRIs. Results showed no hip collapse with angles up to 190° in 4 hips, half-collapsed hips at angles between 190° to 240° in 4 hips, and fully collapsed hips at angles of 240° or greater in 25 hips.22 A 2010 study demonstrated 101 asymptomatic hips with medially located small lesions (Kerboul angle less than 200°) had a rate of collapse less than 10%, compared with 25% for the remainder.23

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1: Hip and Knee

Figure 2

T1-weighted coronal MRIs of the femoral head showing a precollapse lesion of the femoral head (arrows). The separate coronal images demonstrate the extent of the lesion (dark areas). (Reproduced with permission from Mont MA, Cherian JJ, Sierra RJ, Jones LC, Lieberman JR: Nontraumatic osteonecrosis of the femoral head: Where do we stand today? A ten-year update. J Bone Joint Surg Am 2015;97[19]:1604-1627.)

Table 2

Overview of Commonly Used Plain Radiographic Staging Systems Association Research Circulation Osseous

Japanese Orthopaedic Association

Stage

Findings

Stage

Findings

Stage

Findings

Stage

Findings

0

Normal hip

1

Demarcation line

1

Normal radiograph

0

Normal hip

1

MRI findings only

2

Early femoral head flattening

2

Diffuse sclerotic/ cystic lesions

1

MRI findings only

2

Focal osteoporosis, cystic lesions, sclerosis

3

Cystic lesions

3

Crescent sign (subchondral fracture)

2

Diffuse cystic/ sclerotic lesions

3

Crescent sign (subchondral fracture)

4

Acetabular involvement, femoral head collapse

3

Subchondral step-off

4

Acetabular involvement

4

Femoral head flattening

5

Acetabular involvement or joint space narrowing

6

Advanced joint degeneration

Treatment

The course of treatment for osteonecrosis depends on the stage of progression and the presence of symptoms. A study of the contralateral asymptomatic hip in 40 hips showed that 88% became symptomatic and 73% collapsed in 11 years.24 Another study showed that 7% of

48

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Ficat and Arlet

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

small and 80% of large lesions (Kerboul angle greater than 240°) collapsed in 8 years.25 Spontaneous resolution can occur in small asymptomatic lesions, and treatment should be considered in moderate to large asymptomatic lesions.26Figure 3 is a suggested algorithm for management of hip osteonecrosis.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 4: Osteonecrosis of the Hip and Knee

1: Hip and Knee

Figure 3

Algorithm for the management of hip osteonecrosis. NVBG = nonvascularized bone grafting, THA = total hip arthroplasty, VBG = vascularized bone grafting. (Reproduced with permission from Mont MA, Cherian JJ, Sierra RJ, Jones LC, Lieberman JR: Nontraumatic osteonecrosis of the femoral head: Where do we stand today? A ten-year update. J Bone Joint Surg Am 2015;97[19]:1604-1627.)

Nonsurgical Management

The use of several drug types such as lipid-lowering drugs, antiplatelet and anticoagulant agents, and diphosphonates can have some benefit with osteonecrosis. Lipid-lowering agents such as statins can manipulate lipid deposition and target thrombosis. Antiplatelet and anticoagulant agents have been hypothesized to prevent progression of early osteonecrosis and may improve blood flow, more likely in patients who have inherited coagulation disorders. Diphosphonates are used to increase bone mineral density and improve clinical function. Alternative modalities such as extracorporeal shock wave therapy and hyperbaric oxygen have shown improvement in pain and functional scores. Although these nonsurgical modalities have reported benefits, studies are limited and insufficient evidence exists to support such claims. Surgical Management

Surgical treatment includes either joint preservation techniques (core decompression with or without adjunctive procedures and rotational osteotomies) in precollapse lesions, or arthroplasty in advanced disease.

© 2017 American Academy of Orthopaedic Surgeons

Core Decompression Good outcomes have been demonstrated in hips with symptomatic, precollapse, and small- to medium-sized lesions, with failure rates of 14% to 25%.5 Trephines (8to 10-mm) or multiple (two to three) percutaneous holes drilled (3.2 mm) into the area of subchondral necrosis are used to reduce intraosseous pressure and prevent further compression.26 More selective indications for core decompression (only smaller precollapse lesions) and improved techniques, particularly since 1992, 27 have resulted in better outcomes. Multiple drilling has also been compared with traditional core decompression with equally good results.28 One study demonstrated that of 120 hips that underwent multiple drilling, 93 (78%) survived at 5-year follow-up; of 59 hips with small to medium-sized lesions, 52 (88%) required no additional surgery.29 One study evaluated the outcomes of multiple percutaneous drillings in precollapse osteonecrosis of the femoral head and reported successful outcomes, with minimal morbidity in 80% of patients who had Ficat and Arlet stage 1 disease.30 A 2010 study evaluated 76 precollapse hips in patients who underwent treatment with core decompression and implantation of a biomaterial-loaded

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Section 1: Hip and Knee

allograft threaded cage and reported a 91% success rate and significantly improved functional outcomes (63 to 82 points on the Harris Hip Score) compared with core decompression alone.31 Core decompression can be used as the first surgical treatment option for symptomatic small to medium-sized precollapse lesions only. Adjunctive treatments have not influenced outcomes and cannot currently be recommended.

1: Hip and Knee

Femoral Osteotomy Rotational or angular osteotomies aim to redistribute weight-bearing forces from necrotic areas to healthy cartilage. Success rates range from 82% to 100% at 3- to 15year follow-up (evidence levels II to IV) for rotational, and 82% to 98% at 6- to 18-year follow-up (evidence levels III and IV) for angular osteotomy.13,32 One study examined angular osteotomy in 73 hips and reported 92% survivorship at 12 years.33 Despite good outcomes, the use of femoral osteotomy is less popular because of the inherent technical challenges, limited use in small lesions, associated complications (delayed union and nonunion, loss of position and or/fixation), and complex conversions to THA. One study demonstrated longer surgical time and higher transfusion rates in 14 patients with conversion of osteotomy to THA, compared with routine THA.32 Bone Graft Nonvascularized

Nonvascularized bone grafting (NVBG) is often used in patients in whom core decompression has failed. The necrotic segment is decompressed and the autograft or allograft material is implanted in the femoral head to provide structural support and allow healing and subchondral bone remodeling.23 The segment is accessed through a core track or cortical window at the base of the femoral head-neck junction known as the lightbulb, trapdoor, or Phemister technique, which is indicated for medium-sized or larger precollapse or early postcollapse lesions. Several studies of NVBG have reported success rates that range from 67% to 91%. In one study, the lightbulb technique (NVBG with bone morphogenetic protein 7 through a cortical window) had a 67% success rate in 39 hips, which improved to 81% (18 of 22 hips) with early-stage lesions.34 A level II study showed that an allograft procedure had 84% survival (46 of 55 hips) at 3-year follow-up.31 One study on NVBG used the trapdoor technique in 33 hips and reported at 2-year follow-up that 80% of hips with Ficat and Arlet stage II disease did not need additional surgery.34 These studies show that NVBG can delay the need for THA in young patients with small to medium-sized precollapse or early postcollapse lesions.

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Vascularized

Like NVBG, vascularized bone grafting (VBG) provides structural support to allow subchondral bone healing and remodeling and also restores vascular supply (pedicle grafting). This revascularization can be from bone, such as from the fibula to the lateral circumflex artery and from the iliac crest to deep circumflex iliac vessels; or from muscle, such as from the quadratus femoris, sartorius, tensor fascia lata, and gluteus medius. VBG is used for early postcollapse lesions, ideally from reversible causes. Survival rates are 80% to 100%; however, outcomes are poorer after collapse occurs.5 One study followed 103 patients for a minimum of 5 years following treatment for osteonecrosis of the hips using a vascularized fibular graft. The study demonstrated that the treatment of small and medium precollapse lesions had the best results. Of 75 patients who answered a questionnaire, 81% were satisfied with the results. Of 24 of 62 hips (39%) with a more advanced lesion, only 5 of 22 hips (23%) had satisfactory results, and 2 of 19 hips (11%) with a precollapse injury were converted to a THA.35 One study produced an 88% success rate with VBG and the mean Harris Hip Scores improved from 50 to 91 points.36 Another study of 120 hips that underwent multiple drilling reported a 78% survivorship (93 hips) at 5-year follow-up, and 88% of hips (52 of 59) with small- to medium-sized lesions required no additional surgery. 29 Age may be a factor with mixed outcomes in patients older than 40 years.23,31 One study of VBG augmented with MSCs mixed with β-tricalcium-­phosphate reported a 94% survival in 30 hips at 99-month follow-up. Despite the lack of randomized controlled trials, VBG results in good outcomes in precollapse disease. Mesenchymal Stem Cells MSCs are usually delivered into the core decompression track to allow them to differentiate into osteoblasts. MSCs can be derived from bone marrow and adipose tissue which, although unconfirmed in humans, have survived, proliferated, and differentiated in animal models.37 Randomized controlled trials examining core decompression and MSCs compared with core decompression alone have shown favorable outcomes regarding Harris Hip Score, lesion size, and time to collapse in 100 patients followed up for 60 months.36 In a literature review that compared the clinical and radiologic improvement of autologous MSC implantation into the core decompression track versus using the core compression alone, it was suggested that the survival of the femoral head would improve and minimize the need for hip arthroplasty when autologous MSCs are used during the precollapse stages of osteonecrosis of the femoral head.38 Despite these promising results for the use

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Chapter 4: Osteonecrosis of the Hip and Knee

of MSCs in core decompression and bone grafting techniques, the process is currently experimental and more research on the mechanism of treatment of osteonecrosis of the femoral head is needed. In addition, the restrictions on MSC use in some countries and substantial resource requirement present a barrier to widespread use.

© 2017 American Academy of Orthopaedic Surgeons

Osteonecrosis of the Knee The specific cause of osteonecrosis of the knee is still largely unknown. There are three types of knee osteonecrosis: primary (or spontaneous osteonecrosis of the knee [SONK]), secondary (also called atraumatic, idiopathic, or ischemic osteonecrosis), and postarthroscopic. SONK has an incidence of 9.4% in women older than 65 years.44 Secondary osteonecrosis affects younger patients (younger than 45 years) and women more often than men (a ratio of 4:1), similarly to hip osteonecrosis.45 Few cases of postarthroscopic osteonecrosis are reported each year, usually occurring in patients in their fifth decade, and it commonly occurs at the medial femoral condyle (Table 3). One study of 50 patients reported that in 2 patients (4%), postarthroscopic osteonecrosis developed.46 In the acute phase, all patients may have an effusion with reduced range of motion. Plain weight-bearing radiographs should be obtained initially with all types of osteonecrosis, although the images appear normal in the early stages of disease.45 Additionally, radiographs may show increased bone density from new bone formation next to the necrotic bone, accentuated by surrounding osteopenia. Diagnosis of each type of osteonecrosis is confirmed using MRI, which has positive findings in the early stages of disease for bone edema, focal epiphyseal depressions, and low-signal subchondral and deep linear signal intensities on T2-weighted images.47 Management of osteonecrosis of the knee depends on the type, symptoms, and stage of disease. Classification systems (Table 4) can help guide staging: the Koshino classification48 was later modified so that stage 1 is normal, stage 2 is a mild flattening of weight-bearing surface, stage 3 is a subchondral lucency, stage 4 is a collapse of the subchondral bone, and stage 5 is characterized by secondary degenerative change.49 The size of the osteonecrotic lesion is prognostic, and various methods are available for measurement. The first method multiplies the width of the lesion measured on AP and lateral radiographs. Small lesions (less than 3.5 cm 2) usually regress, medium lesions (range, 3.5 to 5.0 cm 2) may or may not progress, and large lesions (larger than 5 cm2) usually progress to condylar collapse.49,50 The second method calculates the lesion size as a percentage of the affected femoral condyle on the AP radiograph. One study showed that 6 of 23 patients (26%) with a mean involvement of 32% of the medial femoral condyle required surgery, whereas all 79 patients with more

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1: Hip and Knee

Total Hip Arthroplasty THA is indicated when there is femoral head collapse with or without secondary osteoarthritis, and nonsurgical management has failed. Advances in techniques and implant technology such as highly cross-linked polyethylene, newer-generation ceramic bearings, and more completely porous coated surfaces have improved outcomes and have shown excellent results at short- to midterm follow-up.13 A 2013 study reported a 100% survivorship and a mean Harris Hip Score of 93 points (range, 77 to 98 points) for THA patients with osteonecrosis using highly cross-linked polyethylene after a minimum follow-up of 5 years.39 In addition, a 2012 study evaluated patients younger than 20 years who received a ceramic-on-ceramic bearing surface and reported an implant survival rate of 96% and a mean Harris Hip Score of 93 points (range, 66 to 100 points) after a mean follow-up of 52 months (range, 25 to 123 months).40 Previously, THA performed for osteonecrosis has had poor outcomes, with rates of aseptic loosening between 8% and 37% and a revision rate of 17% at 9 years.41 These patients tended to be younger and placed high demands on their THAs, risking polyethylene wear, osteolysis, and ceramic fracture. Newer studies with follow-up of more than 10 years42,43 demonstrate low wear rates on radiostereometric analysis, suggesting that osteonecrosis is no longer a substantially negative factor for THA.42,43 Previously, concerns existed that osteonecrosis could hinder ingrowth in noncemented implants. However, a 2013 study reported significantly lower rates of aseptic loosening in noncemented implants compared with cemented implants.42 In addition, a 2013 study of noncemented implants in 64 hips showed survival rates of 100% for aseptic loosening and 94% for all causes at a mean follow-up of 15.8 years.43 In addition, the etiology of the osteonecrosis may influence the rate of aseptic loosening. In a meta-analysis of 3,277 hips, higher failure rates were reported in patients who had osteonecrosis secondary to sickle cell disease, Gaucher disease, and following renal transplantation. Lower rates of osteonecrosis were seen in patients with idiopathic disease, with SLE, and following heart transplantation.41 The overall quality of the bone stock still remains important for the outcomes. Finally, many of these patients had undergone other surgical procedures before THA such as core decompression,

bone grafting, hemiresurfacing, and total hip resurfacing; however, survival was 95%, 97%, 88%, and 91%, respectively, at 6-year follow-up.26

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Table 3

Clinical Presentation and Etiology in Osteonecrosis of the Knee Type

Age

Bilaterality

Other Joint Involvement

Associated Risk Factors

Lesion Description

Older than 50 years

< 5%

No

Microtrauma, chronic mechanical stress, idiopathic

Bony fibrosis, healing fracture, osteoarthritis, osteopenia, necrosis only at distal portion of fractured segment

Secondary osteonecrosis

Younger than 45 years

> 80%

> 90% (commonly shoulder, hip, ankle)

Indirect causes: corticosteroid use, inflammatory bowel disease, smoking, systemic lupus erythematosus, coagulation abnormalities (hypofibrinolysis, thrombophilia)

Necrotic bone

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Spontaneous osteonecrosis of the knee

Direct causes: chemotherapy, radiation, trauma, caisson disease, Gaucher disease Postarthroscopic osteonecrosis

Any

No

No

than 50% involvement progressed to collapse without surgery and ultimately required arthroplasty.51 In secondary osteonecrosis, large epiphyseal lesions were found to have a substantially worse prognosis than metaphyseal or diaphyseal lesions.45 Postarthroscopic osteonecrosis does not correlate as well with lesion size. Algorithms can be used to plan the management of primary (Figure 4), secondary (Figure 5), and postarthroscopic (Figure 6) osteonecrosis of the knee. Spontaneous Osteonecrosis of the Knee Etiology and Pathogenesis

SONK typically presents as a unilateral, focal, subchondral lesion affecting a single joint and condyle. The medial femoral condyle is most commonly involved (more than 90% of cases). It is theorized that minor trauma in the setting of osteopenic bone, which affects 75% of patients with SONK, causes subchondral insufficiency fractures. Fluid accumulates in these potential spaces, causing

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Anterior cruciate ligament reconstruction, meniscectomy, laser- or radiofrequencyassisted surgery, or cartilage débridement

Healing fracture and bony fibrosis; bone necrosis after direct thermal or acoustic injury

edema, focal ischemia, and eventual necrosis.44,45 A 2009 study of 22 patient specimens reported no evidence of osteonecrosis was found; however, 64% (14 of 22) showed evidence of osteopenia and 68% showed evidence of osteoarthritis (15 of 22).44 Overall, SONK is thought to be underdiagnosed, and many patients who present with osteoarthritis may actually have occult SONK. Evaluation and Diagnosis

SONK causes acute, severe medial knee pain, which is worse on weight bearing and typically occurs at night. Usually, no history of trauma is reported, although a few patients report preceding trauma. With SONK, tenderness is found on the medial femoral condyle (or affected area). Imaging

On plain radiographs, radiolucencies with a surrounding sclerotic halo and flattening of the femoral condyle

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Chapter 4: Osteonecrosis of the Hip and Knee

may be seen, mainly affecting the epiphysis. Late disease stages show a crescent sign from collapse of the necrotic bone segment from the subchondral bone, followed by full collapse, femoral condyle flattening, and osteoarthritis (Figure 7). An early MRI for SONK may have normal findings; therefore, it should be performed 4 to 6 weeks following symptom onset. Usually, one necrotic lesion with a low signal intensity is seen on T1- and T2-­ weighted images, surrounded by marrow edema, affecting the whole condyle. Other findings can include articular cartilage abnormalities, loose bodies, and sclerosis.

Table 4

Staging Systems for Osteonecrosis of the Knee Description

Koshino

For primary/spontaneous osteonecrosis of the knee

 I

Knee symptoms, radiographs normal

 II

Radiographic flattening and subchondral lucencies on weightbearing area, surrounded by osteosclerosis

 III

Radiographic extension of subchondral lucencies around affected area and subchondral collapse

 IV

Radiographic degenerative change with osteosclerosis and osteophyte formation

Modified Ficat and Arlet

For secondary and postarthroscopic

 I

Normal joint space, no subchondral collapse, osteoporosis mottled areas

 II

Normal joint space, no subchondral collapse, wedge sclerosis in trabeculae

 III

Normal or slightly narrowed joint space, subchondral collapse, trabecular sequestration (‘crescent sign’)

 IV

Narrowed joint space, subchondral collapse, extensive destruction

Nonsurgical Treatment

Protected weight bearing for 4 to 6 weeks, physical therapy, analgesics, and NSAIDs are indicated for small lesions (less than 3.5 cm2). Some patients in the early stages of SONK who are treated nonsurgically usually experience resolution of symptoms and MRI findings within 3 to 8 months.4 One study showed none of the 10 patients with less than 20% involvement required surgery at 9-year follow-up.52 Another study of 79 cases of stage 1 SONK of the medial femoral condyle showed 89% resolution after nonsurgical treatment; only 1 patient required TKA.51 Diphosphonates can prevent or delay the need for surgery by inhibiting bone resorption and were shown to prevent subchondral collapse in femoral head osteonecrosis.53 After a minimum of 6 months of treatment with alendronate, subchondral collapse developed in 3 of 17 patients (18%) with SONK (all 3 stopped treatment prematurely).52 However, a randomized controlled trial compared diphosphonates with NSAIDs for early SONK and reported no benefit regarding pain scores and radiologic outcomes.54 A promising nonsurgical treatment is pulsed electromagnetic field therapy, which has been shown to reduce pain and the size of the necrotic lesion in SONK at 6 months.55

1: Hip and Knee

Classification and Stage

Data from Woehnl AN, Naziri Q, Costa C, et al: Osteonecrosis of the knee. Orthopaedic Knowledge Online Journal 2012;10(5); and Koshino T, Okamoto R, Takamura K, Tsuchiya K: Arthroscopy in spontaneous osteonecrosis of the knee. Orthop Clin North Am 1979;10(3):609-618.

Surgical Treatment

Surgery is indicated when no clinical or radiographic improvement is seen after 3 months of nonsurgical treatment or in patients with large osteonecrotic lesions (larger than 3.5 cm2 or greater than 50% of the condyle). However, the risk of progression to collapse is high.6,45,51 Initially, joint preservation techniques can be used, ideally in the precollapse state, including arthroscopy (microfracture, chondroplasty, or meniscectomy), core decompression, osteochondral allograft techniques, and high tibial osteotomy. Using the Cincinnati Knee Rating System, microfracture resulted in clinical improvement in 25 of 26 patients (96%) with SONK at 27-month follow-up.56 In another study, core decompression improved immediate

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postoperative knee pain in all 16 patients (15 with stages 1 and 2, 1 with stage 3), and those with early-stage disease had normalization of bone marrow signal intensity on latest follow-up MRI.57 Core decompression is effective in delaying the need for TKA, and the addition of calcium hydroxyapatite bone graft to the core track has also demonstrated good outcomes.58 Osteochondral allograft techniques allow restoration of the articular cartilage following subchondral collapse. The principles of osteochondral allografting are to remove the collapsed tissue and replace it with structurally sound osteochondral tissue. Outcomes have been excellent, despite small numbers, including a study in which eight of nine patients with SONK had a successful outcome with postoperative

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Section 1: Hip and Knee

Figure 4

Algorithm for the management of spontaneous osteonecrosis of the knee. SONK = spontaneous osteonecrosis of the knee, TKA = total knee arthroplasty, UKA = unicompartmental knee arthroplasty. (Reproduced with permission from Karim AR, Cherian JJ, Jauregui JJ, Pierce T, Mont MA: Osteonecrosis of the knee: Review. Ann Transl Med 2015;3[1]:6).

Figure 5

Management of secondary osteonecrosis of the knee. TKA = total knee arthroplasty. (Reproduced with permission from Karim AR, Cherian JJ, Jauregui JJ, Pierce T, Mont MA: Osteonecrosis of the knee: Review. Ann Transl Med 2015;3[1]:6).

mean Knee Society Score (KSS) of 85 points at 40-month follow-up.58 For younger, more active patients, high tibial osteotomy shifts the weight-bearing axis to offload the affected condyle, reduces pain, and potentially allows healing. Although it cannot be used in multifocal (such as secondary) osteonecrosis, it has demonstrated excellent outcomes in other cases.6 One study of 78 knees (in 64 patients) that underwent high tibial osteotomy with bone substitute reported significantly improved mean

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scores (KSS knee, 50 points preoperatively to 88 points postoperatively; KSS functional, 57 points preoperatively to 89 points postoperatively) at 6.5-year follow-up.59 Importantly, the results were equally good in those older than 70 years. Core decompression also can be successfully implemented with this technique.4 In advanced disease with collapse, and/or when joint preservation techniques fail, arthroplasty should be considered. Unicompartmental knee arthroplasty (UKA) is an

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Chapter 4: Osteonecrosis of the Hip and Knee

Figure 7

Management of postarthroscopic osteonecrosis of the knee. SONK = spontaneous osteonecrosis of the knee. (Reproduced with permission from Karim AR, Cherian JJ, Jauregui JJ, Pierce T, Mont MA: Osteonecrosis of the knee: Review. Ann Transl Med 2015;3[1]:6).

option for involvement of only one condyle, but historically has had poor outcomes. More recently, outcomes have been good with improved techniques and implants.59 A retrospective study of 52 patients who underwent UKA for SONK demonstrated improved KSS from 85 points preoperatively to 173 points at 10-year follow-up.60 Survival was 93% and 91% at 10 and 15 years, respectively. Another study compared the medial Oxford UKA (Biomet) in 29 knees (27 patients) with SONK in 28 knees (26 patients) with osteoarthritis and reported similar Oxford UKA knee scores at 5 years postoperatively (38 and 40 points, respectively). No failures were reported in either group at 5-year follow-up.61 When more than one compartment is affected, TKA is recommended. A systematic review of 148 patients reported those who underwent TKA for SONK had the best outcomes compared with TKA for secondary osteonecrosis and UKA for SONK; those who underwent TKA for SONK had better postoperative knee scores and lower revision rates,59 making them comparable to patients with osteoarthritis. Secondary Osteonecrosis Etiology and Pathogenesis

With secondary osteonecrosis, multiple diffuse lesions are usually seen in both the femoral and tibial condyles

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1: Hip and Knee

Figure 6

Images of a patient with secondary osteonecrosis undergoing hemodialysis. A, Bilateral AP radiographs demonstrate collapse of the medial femoral condyle in the right knee and total knee arthroplasty in the left. B, T1-weighted coronal MRI of the right knee shows osteonecrosis and collapse of the medial femoral condyle from secondary osteonecrosis (arrows).

(bilateral in 80% of cases), possibly extending into the diaphysis and metaphysis. Multiple joints are also involved, such as the femoral head (90% of cases) and proximal humerus.6 As with the hip, numerous risk factors, both direct and indirect, are involved. Evaluation and Diagnosis

Secondary osteonecrosis presents with gradual onset of pain, usually over the femoral condyles, but also the tibial condyles (20%) and other joints.6 Secondary osteonecrosis presents with more diffuse tenderness from possible multifocal lesions. Imaging

Secondary osteonecrosis has multiple larger lesions with serpentine appearance of radiodense bony infarcts on radiographs. A similar appearance can be noted on MRI and bone scintigraphy: multiple areas of central fatty marrow signal intensity surrounded by a serpentine border of reactive bone with low signal intensity on T1- and high signal intensity on T2-weighted images. Nonsurgical Treatment

Nonsurgical treatment is only recommended in asymptomatic cases of secondary osteonecrosis because symptomatic patients tend to be younger, with larger lesions and poor prognosis. In one study, 8 of 10 asymptomatic patients had no disease progression on radiographs, and did not require surgery at 8-year follow-up.50 The same study also had 41 symptomatic patients, 8 (19%) of whom had satisfactory outcomes

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Section 1: Hip and Knee

(KSS greater than 80 and no surgery) with this approach, and 29 patients (70%) required TKA. Diphosphonates may also play a role in secondary osteonecrosis. One study62 of 28 symptomatic patients treated with pamidronate followed by alendronate reported improvements in pain scores at 6 weeks and greater improvements at 6 months. In addition, 15 patients (53%) had complete resolution of pain and 18 patients (64%) had complete reversal of bone marrow edema on MRI at 6-month follow-up. Prostaglandin I2 has been shown to improve pain, function, and bone marrow edema in early disease, but not in advanced disease.62 Surgical Treatment 1: Hip and Knee

Secondary osteonecrosis of the knee can be treated using joint-preservation techniques in precollapse disease stages. In addition, bone impaction grafting can be performed to help delay the need for arthroplasty. Arthroscopy treats any coexisting chondral and/or meniscal pathologies and is also useful to assess the chondral surface.6 Core decompression can be performed with a small (3 mm) drill into the affected condyle via the metaphysis, under fluoroscopic guidance, followed by partial weight bearing for 4 to 6 weeks. This technique relieves pain with low morbidity and delays further surgery. One study reported a 92% success rate after core decompression, defined as a KSS higher than 80 points in 56 of 61 knees (38 patients):48 of these, success was noted in all small lesions as well as in 86% of large lesions (32 of 37 knees) at 3-year follow-up. In addition, only 2 knees (3%) required TKA at 3-year follow-up.63 Impaction bone grafting is used in solitary early lesions because it involves removal of the osteonecrotic area via a metaphyseal window, and impaction of autograft or allograft to prevent collapse and restore condylar sphericity.45 Although there are few studies assessing impaction bone grafting, early results demonstrate that it may delay the need for TKA in early collapse disease. A study of three patients demonstrated improvements in mean KSS from 63 points preoperatively to 89 points and functional KSS from 19 points preoperatively to 81 points at 2-year follow-up, with no complications and near-normal function and activity levels.64 Another prospective study of nine patients reported no progression of collapse: three patients had signs of early osteoarthritis and overall scores (KSS objective, 63 points preoperatively to 89 points postoperatively; functional, 19 points preoperatively to 81 points postoperatively) improved at 51-month follow-up, and none required TKA.65 Osteochondral allograft transplantation restores the articular cartilage and subchondral bone, including that affected by large lesions. Current data are limited; however, one study with

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28 patients demonstrated an 89% success rate in postcollapse disease at 2-year follow-up, with an increase in functional KSS preoperatively from 60 points to 86 points at final follow-up.66 Importantly, caution is recommended in corticosteroid-related osteonecrosis because treating patients with inadequate graft revascularization and graft subsidence may occur. Finally, arthroplasty should be considered with joint collapse and when joint preservation techniques have failed. Unlike SONK, more diffuse disease occurs in secondary osteonecrosis, warranting TKA. One study reported a survival rate of 97% in 30 patients, with an increase in mean KSS from 54 points preoperatively to 95 points at 108-month follow-up.67 Postarthroscopic Osteonecrosis Etiology and Pathogenesis

Postarthroscopic osteonecrosis of the knee is usually seen following meniscectomy, chondroplasty, and less commonly, anterior cruciate ligament reconstruction. In one study of medial meniscal root tears, elevated hoop stresses caused increased tibiofemoral contact pressures and subchondral insufficiency fractures in 80% of cases.68 Synovial fluid ingress causes edema, subchondral vascular insufficiency, and necrosis. In addition, overly aggressive early rehabilitation before adequate postoperative remodeling has occurred can also cause insufficiency fractures. Evaluation and Diagnosis

Postarthroscopic osteonecrosis also results in acute onset of pain in the area of pathology and surgery, usually 6 to 8 weeks postoperatively, which becomes persistent.68 Each patient will have stiffness and swelling, with potentially worsening pain from progressive collapse. Postarthroscopic osteonecrosis presents with tenderness in the area of the lesion and/or surgical compartment.4 Imaging

Two criteria must be fulfilled for diagnosis of postarthroscopic osteonecrosis: absence of osteonecrosis on preoperative MRI 4 to 6 weeks after symptom onset and a recent history of arthroscopy and development of suspicious bone marrow edema pattern in the surgical compartment on postoperative MRI.45,68 In one study, edema was shown to occur in 32 of 93 patients (34%) undergoing arthroscopic meniscectomy within 8 months, and osteonecrosis developed in none.69 Bone scans show uptake in the affected condyle in all three phases after 72 hours, but are not recommended because of poor sensitivity and specificity. Scintigraphy detects only 56% of multifocal lesions seen on MRI and confirmed histopathologically.4

© 2017 American Academy of Orthopaedic Surgeons

Chapter 4: Osteonecrosis of the Hip and Knee

Nonsurgical Treatment

Nonsurgical treatment should be used only in patients with early-stage, precollapse lesions and includes protected weight bearing, NSAIDs, and analgesics. One study showed that 44 of 47 patients (97.6%) continued to have the same MRI appearance after 6 weeks of protected weight bearing.68 Diphosphonates such as intravenous pamidronate followed by oral alendronate for 4 to 6 months resulted in a decreased pain score at 6 weeks and at 6 months (80% reduction) in 22 patients with osteonecrosis following meniscectomy.70 Surgical Treatment

Summary Osteonecrosis is a challenging condition because it affects young patients with high activity levels and has an unclear etiology. Despite multiple pathophysiologic theories, the final common pathway is ischemia and cell death. The hip is a load-bearing joint and osteonecrosis may result in collapse and secondary osteoarthritis. Small to medium-sized precollapse lesions can be managed nonsurgically or with core decompression; larger lesions can be managed with bone grafting. Early postcollapse hips may be amenable to joint preservation; however, those with late collapse and secondary osteoarthritis require arthroplasty. Secondary osteonecrosis is related to medical conditions and risk factors such as vascular occlusion and bone marrow crowding; primary and postarthroscopic osteonecrosis of the knee are thought to be associated with subchondral insufficiency fractures. Osteonecrosis of the hip and knee is diagnosed by using radiographs and MRIs, with management guided by the presence of symptoms, lesion size, and collapse. Outcomes in these patients have improved over the past several decades, which are reflected in advancements in both surgical and nonsurgical modalities. Further research with longer follow-up should focus on early detection and intervention to minimize joint destruction.

© 2017 American Academy of Orthopaedic Surgeons

• Osteonecrosis of the hip and knee can have various etiologies; however, interruption of the blood supply ultimately is the main culprit. • Effective imaging modalities for osteonecrosis of the hip or knee include plain radiographs, MRI, and CT. Bone scintigraphy and positron emission tomography do not yet have definitive roles in diagnosis. • In general, nonsurgical treatment can be used in early, precollapse lesions. Surgical intervention is indicated in the setting of collapse and/or degeneration of the articular surface. 1: Hip and Knee

Surgical intervention is indicated when there is collapse and/or degeneration of the articular surface. With early disease, joint preservation techniques are indicated, depending on patient age and activity level.6 However, the outcomes of the limited studies on these techniques are less than optimal. In a study of six patients, repeat arthroscopy and core decompression were performed in one patient at 9 months and failed; UKA was necessary 1 year postoperatively.70 With advanced disease and osteoarthritis, knee arthroplasty is indicated, depending on the number of compartments affected.

Key Study Points

Annotated References 1. Jacobs B: Epidemiology of traumatic and nontraumatic osteonecrosis. Clin Orthop Relat Res 1978;130:51-67. Medline 2. Mont MA, Hungerford DS: Non-traumatic avascular necrosis of the femoral head. J Bone Joint Surg Am 1995;77(3):459-474. Medline 3. Cooper C, Steinbuch M, Stevenson R, Miday R, Watts NB: The epidemiology of osteonecrosis: Findings from the GPRD and THIN databases in the UK. Osteoporos Int 2010;21(4):569-577. Medline  DOI This case-control study examined the incidence of osteonecrosis in health record databases in the United Kingdom. Significant risk factors included systemic corticosteroid use, hospitalization, bone fracture, cancer, osteoporosis, and connective tissue disease. 4. Karim AR, Cherian JJ, Jauregui JJ, Pierce T, Mont MA: Osteonecrosis of the knee: Review. Ann Transl Med 2015;3(1):6. Medline This review article discusses diagnosis, medical management, joint preservation techniques, and total joint arthroplasty pertaining to osteonecrosis of the knee. 5. Mont MA, Jones LC, Hungerford DS: Nontraumatic osteonecrosis of the femoral head: Ten years later. J Bone Joint Surg Am 2006;88(5):1117-1132. Medline  DOI 6. Woehnl AN, Naziri Q, Costa C, et al: Osteonecrosis of the Knee. Orthopaedic Knowledge Online Journal 2012;10(5). The authors suggested that the results of joint-preserving procedures are less satisfactory than the results of THA for femoral heads that have already collapsed.

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7. Egol K, Koval KJ, Zuckerman J: Lower extremity fractures and dislocations. Handbook of Fractures Philadelphia .PA, Lippincott, Williams and Wilkins, 2010.

14. Marker DR, Seyler T, Mont MA, McCarthy EF: Osteonecrosis and Bone Marrow Edema Syndrome .USA, Saunders, 2012.

This textbook chapter describes diagnosis and management of lower extremity fractures and dislocations.

This article discusses recent findings of osteonecrosis and the associated bone marrow edema. Excellent outcomes have been observed with use of core decompression and other treatment modalities.

8. Zhao FC, Guo KJ, Li ZR: Osteonecrosis of the femoral head in SARS patients: Seven years later. Eur J Orthop Surg Traumatol 2013;23(6):671-677. Medline  DOI This study analyzed the progression of osteonecrosis of the femoral head in 190 hips of patients with severe acute respiratory syndrome following steroid administration. The authors found that larger lesions and less viable lateral columns were significant risk factors for disease progression.

1: Hip and Knee

9. Aaron RK, Voisinet A, Racine J, Ali Y, Feller ER: Corticosteroid-associated avascular necrosis: Dose relationships and early diagnosis. Ann N Y Acad Sci 2011;1240:38-46. Medline  DOI This review article discusses etiology, pathogenesis, and effects of corticosteroid use on osteonecrosis. The authors argue for MRI screening for at-risk patients to identify osteonecrosis at an earlier, more treatable stage. 10. Chan KL, Mok CC: Glucocorticoid-induced avascular bone necrosis: Diagnosis and management. Open Orthop J 2012;6:449-457. Medline  DOI This review article discusses epidemiology, pathogenesis, diagnosis, staging, and treatment of osteonecrosis. The authors focus on the effect of route, cumulative dose, and duration of steroid use regarding the development of osteonecrosis. 11. Chen C, Yang S, Feng Y, et al: Impairment of two types of circulating endothelial progenitor cells in patients with glucocorticoid-induced avascular osteonecrosis of the femoral head. Joint Bone Spine 2013;80(1):70-76. Medline  DOI

16. Glueck CJ, Freiberg RA, Wang P: Heritable thrombophilia-hypofibrinolysis and osteonecrosis of the femoral head. Clin Orthop Relat Res 2008;466(5):1034-1040. Medline  DOI 17. Flouzat-Lachaniete CH, Roussignol X, Poignard A, Mukasa MM, Manicom O, Hernigou P: Multifocal joint osteonecrosis in sickle cell disease. Open Orthop J 2009;3:32-35. Medline  DOI 18. Shigemura T, Nakamura J, Kishida S, et al: Incidence of osteonecrosis associated with corticosteroid therapy among different underlying diseases: Prospective MRI study. Rheumatology (Oxford) 2011;50(11):2023-2028. Medline  DOI In this prospective MRI study, 1,199 hips and knees were assessed for osteonecrosis for 1 year immediately following the initiation of steroid therapy. The incidence of osteonecrosis is higher in patients who were male, adolescent, adult, or SLE patients as well as those taking more than 40 mg per day of steroids. 19. Lee GC, Khoury V, Steinberg D, Kim W, Dalinka M, Steinberg M: How do radiologists evaluate osteonecrosis? Skeletal Radiol 2014;43(5):607-614. Medline  DOI

The authors collected samples from 33 patients with osteonecrosis of the femoral head secondary to steroid use to analyze the role of endothelial progenitor cells. These patients were found to have reduced the number and function of endothelial progenitor cells.

This study attempted to determine how musculoskeletal radiologists evaluate osteonecrosis of the femoral head: 95% of respondents believe clinical evaluation is important, and only 46% use a specific classification method. The authors advocated for a classification method that uses stage and joint involvement.

12. Drescher W, Bünger MH, Weigert K, Bünger C, Hansen ES: Methylprednisolone enhances contraction of porcine femoral head epiphyseal arteries. Clin Orthop Relat Res 2004;423:112-117. Medline  DOI

20. Ito H, Matsuno T, Minami A: Relationship between bone marrow edema and development of symptoms in patients with osteonecrosis of the femoral head. AJR Am J Roentgenol 2006;186(6):1761-1770. Medline  DOI

13. Mont MA, Cherian JJ, Sierra RJ, Jones LC, Lieberman JR: Nontraumatic osteonecrosis of the femoral head: Where do we stand today? A ten-year update. J Bone Joint Surg Am 2015;97(19):1604-1627. Medline  DOI

21. Lee GC, Steinberg ME: Are we evaluating osteonecrosis adequately? Int Orthop 2012;36(12):2433-2439. Medline  DOI

This review article discusses the latest findings in pathophysiology, joint preservation, and total joint arthroplasty following osteonecrosis of the femoral head. Severe disease treated with total joint arthroplasty has shown excellent outcomes and resurfacing techniques have provided suboptimal results.

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15. Cui Q, Wang Y, Saleh KJ, Wang GJ, Balian G: Alcohol-induced adipogenesis in a cloned bone-marrow stem cell. J Bone Joint Surg Am 2006;88(suppl 3):148-154. Medline  DOI

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

This review article focuses on methods and trends in the evaluation of osteonecrosis of the femoral head over the past 25 years. Although advances in evaluation methods have been made, studies continue to frequently use limited, nonquantitative methods.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 4: Osteonecrosis of the Hip and Knee

22. Ha YC, Jung WH, Kim JR, Seong NH, Kim SY, Koo KH: Prediction of collapse in femoral head osteonecrosis: A modified Kerboul method with use of magnetic resonance images. J Bone Joint Surg Am 2006;88(suppl 3):35-40. Medline  DOI 23. Mont MA, Zywiel MG, Marker DR, McGrath MS, Delanois RE: The natural history of untreated asymptomatic osteonecrosis of the femoral head: A systematic literature review. J Bone Joint Surg Am 2010;92(12):2165-2170. Medline  DOI This review examined asymptomatic osteonecrosis of the femoral head and the prevalence of progression to symptomatic disease or femoral head collapse. Of 16 studies examined, 394 of 664 hips (59%) had progression to symptoms or collapse.

30. Mont MA, Ragland PS, Etienne G: Core decompression of the femoral head for osteonecrosis using percutaneous multiple small-diameter drilling. Clin Orthop Relat Res 2004;429:131-138. Medline  DOI 31. Yang S, Wu X, Xu W, Ye S, Liu X, Liu X: Structural augmentation with biomaterial-loaded allograft threaded cage for the treatment of femoral head osteonecrosis. J Arthroplasty 2010;25(8):1223-1230. Medline  DOI In this prospective analysis, 76 patients with osteonecrosis of the femoral head were allocated to receive either core decompression alone or core decompression and implantation of a biomaterial-loaded allograft threaded cage. Patients in the latter group had significantly improved Harris Hip Scores and better clinical success rates at 36 months postoperatively. 32. Issa K, Johnson AJ, Naziri Q, Khanuja HS, Delanois RE, Mont MA: Hip osteonecrosis: Does prior hip surgery alter outcomes compared to an initial primary total hip arthroplasty? J Arthroplasty 2014;29(1):162-166. Medline  DOI

25. Nakamura J, Harada Y, Oinuma K, Iida S, Kishida S, Takahashi K: Spontaneous repair of asymptomatic osteonecrosis associated with corticosteroid therapy in systemic lupus erythematosus: 10-year minimum follow-up with MRI. Lupus 2010;19(11):1307-1314. Medline  DOI

In this study, clinical and radiographic outcomes in 87 patients who underwent hip preservation techniques were compared with those of 105 patients who underwent THA. No differences were observed in survivorship, or clinical or radiographic outcomes at a mean of 75 months.

This retrospective analysis on the use of corticosteroid therapy in patients with SLE having asymptomatic osteonecrosis reported that almost one-half of all joints demonstrated spontaneous repair in the necrotic area at final follow-up. 26. Banerjee SK, Cherian JJ, Jauregui JJ, Mont MA: Multifocal Osteonecrosis .New York, Springer, 2014. DOI

33. Zhao G, Yamamoto T, Ikemura S, et al: Radiological outcome analysis of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head at a mean follow-up of 12.4 years. J Bone Joint Surg Br 2010;92(6):781-786. Medline  DOI

This study used MRI to document the long-term natural history of asymptomatic osteonecrosis associated with corticosteroid therapy in SLE patients.

This retrospective review of 73 hips separated into two groups based on radiologic findings of osteonecrosis reported a postoperative intact ratio cutoff point to prevent both progression of collapse and joint space narrowing of 41.9%.

27. Marker DR, Seyler TM, Ulrich SD, Srivastava S, Mont MA: Do modern techniques improve core decompression outcomes for hip osteonecrosis? Clin Orthop Relat Res 2008;466(5):1093-1103. Medline  DOI

34. Seyler TM, Marker DR, Ulrich SD, Fatscher T, Mont MA: Nonvascularized bone grafting defers joint arthroplasty in hip osteonecrosis. Clin Orthop Relat Res 2008;466(5):1125-1132. Medline  DOI

28. Al Omran A: Multiple drilling compared with standard core decompression for avascular necrosis of the femoral head in sickle cell disease patients. Arch Orthop Trauma Surg 2013;133(5):609-613. Medline  DOI

35. Urbaniak JR, Coogan PG, Gunneson EB, Nunley JA: Treatment of osteonecrosis of the femoral head with free vascularized fibular grafting. A long-term follow-up study of one hundred and three hips. J Bone Joint Surg Am 1995;77(5):681-694. Medline

Classic and multiple-drilling approaches were compared for the management of osteonecrosis of the femoral head in patients with sickle cell disease. Multiple drilling was found to be safer and less invasive in this population. However, no differences were reported in outcomes or complications between cohorts. 29. Song WS, Yoo JJ, Kim YM, Kim HJ: Results of multiple drilling compared with those of conventional methods of core decompression. Clin Orthop Relat Res 2007;454(454):139-146. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

24. Hernigou P, Poignard A, Nogier A, Manicom O: Fate of very small asymptomatic stage-I osteonecrotic lesions of the hip. J Bone Joint Surg Am 2004;86-A(12):2589-2593. Medline

36. Zhao D, Cui D, Wang B, et al: Treatment of early stage osteonecrosis of the femoral head with autologous implantation of bone marrow-derived and cultured mesenchymal stem cells. Bone 2012;50(1):325-330. Medline  DOI Ex vivo expansion of autologous bone marrow–derived MSCs can reliably provide a greater number of bone marrow–derived MSCs for femoral head implantation. 37. Wang B, Zhao D, Liu B, Wang W: Treatment of osteonecrosis of the femoral head by using the greater trochanteric

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bone flap with double vascular pedicles. Microsurgery 2013;33(8):593-599. Medline In this study, outcomes following the use of greater trochanteric bone flaps in 32 patients with osteonecrosis of the femoral head were assessed. Only 2 patients required hip replacement at a mean follow-up of 99.5 months. The authors advocated for the use of this easier, less morbid procedure in young patients with stage II or III disease. 38. Papakostidis C, Tosounidis TH, Jones E, Giannoudis PV: The role of “cell therapy” in osteonecrosis of the femoral head. Acta Orthop 2016;87(1):72-78. Medline  DOI

1: Hip and Knee

The authors of this study suggest that implantation of autologous MSCs into the core decompression track, particularly at early (precollapse) stages of osteonecrosis of the femoral head, improves the survivorship of femoral heads and reduces the need for hip arthroplasty. 39. Min BW, Lee KJ, Song KS, Bae KC, Cho CH: Highly cross-linked polyethylene in total hip arthroplasty for osteonecrosis of the femoral head: A minimum 5-year follow-up study. J Arthroplasty 2013;28(3):526-530. Medline  DOI This study evaluated 162 hips with osteonecrosis of the femoral head that underwent THA using highly crosslinked polyethylene liners. After a minimum follow-up of 5 years, there was no radiographic evidence of loosening or osteolysis, and no revisions were reported.

4 4. Mears SC, McCarthy EF, Jones LC, Hungerford DS, Mont MA: Characterization and pathological characteristics of spontaneous osteonecrosis of the knee. Iowa Orthop J 2009;29:38-42. Medline 45. Mont MA, Marker DR, Zywiel MG, Carrino JA: Osteonecrosis of the knee and related conditions. J Am Acad Orthop Surg 2011;19(8):482-494. Medline  DOI The authors of this study suggest that secondary osteonecrosis frequently progresses to end-stage disease, and early surgical intervention is recommended. Initial management of spontaneous osteonecrosis of the knee and postarthroscopic osteonecrosis is typically nonsurgical, with observation for clinical or radiographic progression. 46. Cetik O, Cift H, Comert B, Cirpar M: Risk of osteonecrosis of the femoral condyle after arthroscopic chondroplasty using radiofrequency: A prospective clinical series. Knee Surg Sports Traumatol Arthrosc 2009;17(1):24-29. Medline  DOI 47. Fotiadou A, Karantanas A: Acute nontraumatic adult knee pain: The role of MR imaging. Radiol Med 2009;114(3):437-447. Medline  DOI

40. Finkbone PR, Severson EP, Cabanela ME, Trousdale RT: Ceramic-on-ceramic total hip arthroplasty in patients younger than 20 years. J Arthroplasty 2012;27(2): 213-219. Medline  DOI

48. Koshino T, Okamoto R, Takamura K, Tsuchiya K: Arthroscopy in spontaneous osteonecrosis of the knee. Orthop Clin North Am 1979;10(3):609-618. Medline

This study reports promising results at short-term to midterm follow-up in young patients who undergo THA using ceramic-on-ceramic components.

49. Aglietti P, Insall JN, Buzzi R, Deschamps G: Idiopathic osteonecrosis of the knee. Aetiology, prognosis and treatment. J Bone Joint Surg Br 1983;65(5):588-597. Medline

41. Johannson HR, Zywiel MG, Marker DR, Jones LC, McGrath MS, Mont MA: Osteonecrosis is not a predictor of poor outcomes in primary total hip arthroplasty: A systematic literature review. Int Orthop 2011;35(4): 465-473. Medline  DOI

50. Mont MA, Baumgarten KM, Rifai A, Bluemke DA, Jones LC, Hungerford DS: Atraumatic osteonecrosis of the knee. J Bone Joint Surg Am 2000;82(9):1279-1290. Medline

This study reported that osteonecrosis, alone or associated with the most common risk factors and/or diagnoses, is not associated with poor outcomes in THA. 42. Bedard NA, Callaghan JJ, Liu SS, Greiner JJ, Klaassen AL, Johnston RC: Cementless THA for the treatment of osteonecrosis at 10-year follow-up: Have we improved compared to cemented THA? J Arthroplasty 2013;28(7):1192-1199. Medline  DOI For noncemented fixation in THAs for osteonecrosis, this study reported durable results with bearing surface wear as the major long-term problem. 43. Kim SM, Lim SJ, Moon YW, Kim YT, Ko KR, Park YS: Cementless modular total hip arthroplasty in patients younger than fifty with femoral head osteonecrosis: Minimum fifteen-year follow-up. J Arthroplasty 2013;28(3): 504-509. Medline  DOI

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The authors of this study suggested that noncemented THA with a modular stem is a promising procedure for young, active patients with osteonecrosis of the femoral head.

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

51. Lotke PA, Abend JA, Ecker ML: The treatment of osteonecrosis of the medial femoral condyle. Clin Orthop Relat Res 1982;171:109-116. Medline 52. Juréus J, Lindstrand A, Geijer M, Robertsson O, Tägil M: The natural course of spontaneous osteonecrosis of the knee (SPONK): A 1- to 27-year follow-up of 40 patients. Acta Orthop 2013;84(4):410-414. Medline  DOI The authors of this study suggest that the size of the osteonecrotic lesion can be used to predict the outcome. Patients with early signs of osteoarthritis or with a large area of osteonecrosis have a high risk of later major knee surgery. 53. Lee YK, Ha YC, Cho YJ, et al: Does Zoledronate Prevent Femoral Head Collapse from Osteonecrosis? A Prospective, Randomized, Open-Label, Multicenter Study. J Bone Joint Surg Am 2015;97(14):1142-1148. Medline  DOI The authors of this study suggest that zoledronate for Steinberg stage I or II osteonecrosis of the femoral head,

© 2017 American Academy of Orthopaedic Surgeons

Chapter 4: Osteonecrosis of the Hip and Knee

with a medium to large necrotic area, did not prevent the collapse of the femoral head or reduce the need for THA 54. Meier C, Kraenzlin C, Friederich NF, et al: Effect of ibandronate on spontaneous osteonecrosis of the knee: A randomized, double-blind, placebo-controlled trial. Osteoporos Int 2014;25(1):359-366. Medline  DOI In this study of patients with spontaneous osteonecrosis of the knee, diphosphonate treatment (intravenous ibandronate) had no beneficial effect over and above anti-inflammatory medication. 55. Marcheggiani Muccioli GM, Grassi A, Setti S, et al: Conservative treatment of spontaneous osteonecrosis of the knee in the early stage: Pulsed electromagnetic fields therapy. Eur J Radiol 2013;82(3):530-537. Medline  DOI

56. Akgun I, Kesmezacar H, Ogut T, Kebudi A, Kanberoglu K: Arthroscopic microfracture treatment for osteonecrosis of the knee. Arthroscopy 2005;21(7):834-843. Medline  DOI 57. Forst J, Forst R, Heller KD, Adam G: Spontaneous osteonecrosis of the femoral condyle: Causal treatment by early core decompression. Arch Orthop Trauma Surg 1998;117(1-2):18-22. Medline  DOI 58. Duany NG, Zywiel MG, McGrath MS, et al: Joint-preserving surgical treatment of spontaneous osteonecrosis of the knee. Arch Orthop Trauma Surg 2010;130(1):11-16. Medline  DOI This report is an overview of the characteristics of SONK and reports the surgeon experience with joint preservation methods of this condition: 87% of patients had a mean KSS of 81 points at a mean follow-up of 40 months. 59. Myers TG, Cui Q, Kuskowski M, Mihalko WM, Saleh KJ: Outcomes of total and unicompartmental knee arthroplasty for secondary and spontaneous osteonecrosis of the knee. J Bone Joint Surg Am 2006;88(suppl 3):76-82. Medline  DOI 60. Langdown AJ, Pandit H, Price AJ, et al: Oxford medial unicompartmental arthroplasty for focal spontaneous osteonecrosis of the knee. Acta Orthop 2005;76(5): 688-692. Medline  DOI 61. Jäger M, Tillmann FP, Thornhill TS, et al: Rationale for prostaglandin I2 in bone marrow oedema—from theory to application. Arthritis Res Ther 2008;10(5):R120. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

63. Lee K, Goodman SB: Cell therapy for secondary osteonecrosis of the femoral condyles using the Cellect DBM System: A preliminary report. J Arthroplasty 2009;24(1):43-48. Medline  DOI 64. Rijnen WH, Luttjeboer JS, Schreurs BW, Gardeniers JW: Bone impaction grafting for corticosteroid-associated osteonecrosis of the knee. J Bone Joint Surg Am 2006;88(suppl 3):62-68. Medline  DOI 65. Görtz S, De Young AJ, Bugbee WD: Fresh osteochondral allografting for steroid-associated osteonecrosis of the femoral condyles. Clin Orthop Relat Res 2010;468(5):12691278. Medline  DOI

1: Hip and Knee

In this study, pulsed electromagnetic field stimulation significantly reduced knee pain and necrosis area in Koshino stage I SONK. No correlation was found between MRI and clinical scores.

62. Marulanda G, Seyler TM, Sheikh NH, Mont MA: Percutaneous drilling for the treatment of secondary osteonecrosis of the knee. J Bone Joint Surg Br 2006;88(6):740-746. Medline  DOI

In this prospective analysis, 28 knees underwent osteochondral allografting for high-grade, corticosteroid-associated osteonecrosis. At a mean 67-month follow-up, graft survival rate was 89% with improvement of various outcome measures. 66. Mont MA, Rifai A, Baumgarten KM, Sheldon M, Hungerford DS: Total knee arthroplasty for osteonecrosis. J Bone Joint Surg Am 2002;84-A(4):599-603. Medline 67. Pape D, Seil R, Anagnostakos K, Kohn D: Postarthroscopic osteonecrosis of the knee. Arthroscopy 2007;23(4): 428-438. Medline  DOI 68. Kobayashi Y, Kimura M, Higuchi H, Terauchi M, Shirakura K, Takagishi K: Juxta-articular bone marrow signal changes on magnetic resonance imaging following arthroscopic meniscectomy. Arthroscopy 2002;18(3):238-245. Medline  DOI 69. Kraenzlin ME, Graf C, Meier C, Kraenzlin C, Friedrich NF: Possible beneficial effect of bisphosphonates in osteonecrosis of the knee. Knee Surg Sports Traumatol Arthrosc 2010;18(12):1638-1644. Medline  DOI In this prospective analysis, the effect of diphosphonate treatment in patients with SONK or arthroscopy-induced osteonecrosis of the knee was investigated. Diphosphonate treatment helped resolve symptoms in 54% of patients. Bone marrow edema resolved completely in 64% of patients. 70. Garino JP, Lotke PA, Sapega AA, Reilly PJ, Esterhai JL Jr: Osteonecrosis of the knee following laser-assisted arthroscopic surgery: A report of six cases. Arthroscopy 1995;11(4):467-474. Medline  DOI

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Chapter 5

Economics and Cost Implications of Total Hip and Total Knee Arthroplasty Richard Iorio, MD  Feroz Osmani, BS  Savyasachi Thakkar, MD

1: Hip and Knee

Abstract Total joint arthroplasty (TJA) is a successful, cost-effective procedure that requires an increasing amount of healthcare resources. Decreased hospital and physician reimbursement and increased costs have put a financial strain on stakeholders involved in the delivery of TJA. Cost analysis of TJA procedures across the United States shows a wide variation in the cost of the surgery. In some cases, newer technology, with no proven track record, has increased the cost of implants, thereby contributing to the increased expense of the procedure. Medicare and Medicaid have implemented alternative payment models such as the Bundle Payment for Care Improvement Initiative and the Comprehensive Care for Joint Arthroplasty, with the purpose of improving the quality of TJA care while reducing cost. Various quality and cost effectiveness improvement measures have been implemented by surgeons and hospitals and have proved to be effective. These programs have included patient risk optimization, multimodal pain management, blood management protocols, implant cost negotiation, and care management initiatives. The goal of these programs is to deliver TJA in a more cost-effective manner without sacrificing quality. In the future, TJA in a value-based purchasing environment will require more attention to cost-effective care delivery.

Keywords: total joint arthroplasty; bundled payments; cost effectiveness; alternative payment models; Dr. Iorio or an immediate family member serves as a paid consultant to DJ Orthopaedics, MCS ActiveCare, and Pacira; has stock or stock options held in Wellbe; has received research or institutional support from APOS Medical & Sports Technologies, Bioventis, Ferring Pharmaceuticals, Orthofix, Orthosensor, Pacira, and Vericel; and serves as a board member, owner, officer, or committee member of the American Association of Hip and Knee Surgeons, Clinical Orthopaedics and Related Research, the Hip Society, JBJS Reviews, the Journal of Arthroplasty, the Journal of Bone and Joint Surgery, the Journal of the American Academy of Orthopaedic Surgeons, and the Knee Society. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Thakkar and Mr. Osmani.

© 2017 American Academy of Orthopaedic Surgeons

Introduction Total joint arthroplasty (TJA) is one of the most commonly performed and successful procedures in the United States. The number of primary TJA procedures performed annually is expected to increase to 4 million by the year 2030.1 Most of these patients are ensured through the Centers for Medicare and Medicaid Services (CMS), which is challenged by financial constraints. This issue is further exacerbated by the Patient Protection and Affordable Care Act (PPACA) of 2010, which has increased insurance coverage of 11 million formerly uninsured patients. For hospitals and physicians, Medicare payments have not increased to match inflation.1 Reducing Costs Associated With TJA The Medicare hospital payment for primary TJA has increased at 50% of the rate of inflation over the past 2 decades, whereas hospital and implant costs have continued to increase.1 TJA costs account for a higher percentage of

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Medicare spending than any other inpatient procedure. Medicare funding for TJA is a continual target for cost containment.1 TJA is the largest diagnosis related group (DRG) expenditure for CMS.1 Additional projected cuts in Medicare reimbursement for TJA and the downstream effects on other healthcare insurance products have potentially negative effects on access to an orthopaedic surgeon specializing in adult reconstruction for TJA.1 In 1992, the national Medicare physician reimbursement rate for total knee arthroplasty (TKA) was $2,102. In 2010, the reimbursement had declined by 30% to $1,470.45.2 An ­inflation-adjusted comparison performed using the dollar value in 1992 reported that the reimbursement for TKA in 2010 is equivalent to $666.58, a 68% reduction in Medicare reimbursement of TKA.2 For the 2014 fiscal year, the average Medicare Physician Fee Schedule cut in payments for orthopaedic procedures was 1%. The American Academy of Orthopaedic Surgeons and the American Association of Hip and Knee Surgeons have worked to minimize these cuts, and in 2015, and no further reductions were made by CMS. Cost Analysis According to a BlueCross BlueShield study of cost variations for TJA in the United States, the average hospital cost of TKA was $31,124 in the 64 markets studied3 and the average cost of total hip arthroplasty (THA) was $30,124.3 A wide price variation exists, depending on geographic location. The price of TKA in Montgomery, Alabama is $11,327, but the price of TKA in New York, New York can be as much as $69,654.3 The hospital cost of THA followed similar trends: $11,327 in Birmingham, Alabama and $73,987 in Boston, Massachusetts.3 Previous studies have reported that more than 75% of hospital expenditures for TJA derive from three main sources: the hospital room cost, the operating room cost, and the implant cost.4-6 Efforts to control these costs can result in substantial improvement in the overall hospital economic performance for TJA.1,6 Inpatient Costs Hospital revenues for TJA increased at a lower rate than did inflation; hospital expenses increased at a rate greater than that of inflation.6 The hospital economics of primary TKA and THA were reported on for an 18-year period between 1990 and 2008 at a single teaching hospital.5,6 The hospital room, operating room, and supplies (medical and surgical) were the three most cost-intensive service centers, comprising more than 70% of hospital expenditures related to primary TJA.5,6 The hospital cost allocation to the hospital room service center decreased 42% in TKA and 5% in THA in inflation-adjusted dollars, primarily

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because of a reduction in hospital length of stay. The cost allocation to the operating room service center decreased 38.0% for TKA in inflation-adjusted dollars because of reduced surgical time; however, the cost allocation increased slightly by 2.4% in THA during the same interval. The supplies service center decreased 53.0% in TKA and 2.4% in THA in inflation-adjusted dollars because of a reduction in knee and hip implant costs.5,6 Overall, the hospital converted a $2,172 loss per case for primary TKA into a $2,986 profit per case and a $3,848 loss per case for primary THA into a $2,359 profit per case.5,6 Additional changes in utilization and unit costs were also made to improve economic results.7 Clinical pathways focused on reducing hospital length of stay were implemented:6 operating room routines were standardized to reduce length of surgery, routine pathologic evaluation of surgical specimens was eliminated,7 wound drains were eliminated, urinary catheter utilization was standardized, routine postoperative TKA radiographs were eliminated,6 routine postoperative noninvasive testing for thromboembolic disease was eliminated,8 and autologous transfusions, reinfusion drains, and cell savers were reduced. In addition, methods were implemented to reduce unit costs of services and supplies associated with TKA such as standardizing operating room packs, reducing inventory, stocking implants on consignment, and reducing cost of implants by developing a single-price/ case-price implant purchasing program.6 Similar cost control strategies were used for THA cas5 es. However, THA-related hospital economics also merit a discussion of alternative joint-bearing surfaces. Several studies suggest that reduced wear rates are related to alternative bearing surfaces, but little long-term clinical benefit exists from such surfaces.9 The cost-effectiveness of alternative bearing surfaces depends highly on patient age at the time of surgery, implant cost, and associated reduction in the probability of revision relative to conventional bearing surfaces.9 The cost burden of alternative bearing surfaces was calculated, and the hospital would have lost $1,147 per patient for ceramic-on-ceramic implants and $534 per patient for metal-on-metal implants.5 Implant Costs The total cost of THA in the United States was reported as twice the cost of the same procedure in Canada, and higher direct costs were explained by the great disparity in implant costs.2 Previous emphasis to contain in-hospital costs relied on reducing length of stay, but such reductions do not necessarily translate to substantial decreases in hospital costs because the volume of services rendered is not substantially reduced by shorter hospitalization.5 Modern cost containment efforts should

© 2017 American Academy of Orthopaedic Surgeons

Chapter 5: Economics and Cost Implications of Total Hip and Total Knee Arthroplasty

Implant Price Negotiation Because CMS does not get involved in setting markets for implants or drugs, the hospital must negotiate the best price possible to limit the cost of TJA.1 An economic analysis demonstrated that although implant cost was affected by hospital factors including volume, number of vendors present, and hospital bed size, a substantial amount for cost variation among hospitals could not be accounted for.1 In addition, substantial cost variation was reported as a result of physician preference.1 Typically, hospitals pay a portion of the list price of an implant, a portion that can vary by case and by hospital. This makes defining the prices paid for implants difficult. List price is generally the starting point in implant negotiations and is not the price paid by most hospitals. Most hospital purchasing contracts have confidentiality clauses that make transparency on average implant costs difficult to determine. The price of TKA implants was defined as a percentage of hospital reimbursement:12 The increasing price of TJA implants offset the gains made in cost control with utilization review. In the 1990s, an education program was instituted for surgeons and a hospital prosthesis application program that began a competitive bid system

© 2017 American Academy of Orthopaedic Surgeons

to decrease the price of TJA implants.1 The Journal of Bone and Joint Surgery endorsed these cost-containment methods, but only if quality of care remained as the focus of any implant selection decision-making process. This philosophy has been extended to the current value-based purchasing movement. In 2012, the New York University Langone Medical Center (NYULMC) Hospital for Joint Diseases implemented a price ceiling implant cost control program.1 The average implant cost per case was effectively reduced by 22% to 33%. In addition, cost variability among physicians decreased by 50% to 90% in all categories. The program resulted in over $2 million saved within its first year. Physician alignment with the hospital as well as other physicians is crucial for effective ceiling price implementation. If alignment is not achieved, vendors will continue to sell higher priced implants, and the implant companies may not limit available implant models and will provide whatever physicians request.1 Physicians must be educated on cost consciousness and the value of patient care. Implants with higher price and newer technology must either demonstrate a solution to a clinical problem not treated by using standard implants or improved patient benefit. Defining new technology and preventing rising costs resulting from innovation are important factors to consider. If the contract is defined by specific components and the components change in any way during the contract, the institution is vulnerable to the implant vendor as to how that new component or part is priced.1 Defining truly new technology and how it is to be implemented are important components of any cost containment program. If truly new technology with improved outcome performance is introduced during the contract, then a price for that technology can be agreed on. New technology introduced during an existing contract should not be accepted at higher prices without clinical performance justification.1 Another method of implant cost control is to ensure proper demand matching. Demand matching provides the appropriate implant based on the functional demand of the patient. It is difficult to demonstrate in the literature that more expensive implants have better survivorship than less expensive implants.13 Implant selection guidelines tend to direct more expensive, newer technology implants for younger, heavier, higher activity patients. Defining these selection guidelines is highly controversial. The Lahey Clinic developed a cost reduction and implant selection program based on demand matching.12 Patients were assigned to demand groups based on five measures: age, weight, bone stock, general health, and the expected postoperative patient activity as determined by the

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include controlling the costs of hospital supplies, especially implants, because a large national variation has been reported in the cost of THA prostheses, with identical implants from a single manufacturer varying by as much as 700%.10 A recent cost-effectiveness study for innovative TKA implants showed that newer implants must reduce TKA failure by 50% to 55% to be considered cost effective and that patient comorbidities and their remaining lifespan are important variables to keep in mind while developing new implants.11 Several factors are associated with implant costs. Patient-specific factors including age and comorbidities are minor factors, but hospital characteristics and physician preference are major considerations.1,6 Establishing a price ceiling on implants is recommended as one method to control and forecast costs. Another effect of standardizing prices was that cost variability among physicians decreased by 50% to 90% in all categories.1 In addition, 96% of requests for higher cost implants were approved because of patient-specific anatomic variations, and surgeons collaborated on the process of price standardization. Vendors were amenable to negotiation because of the threat of price competition.1 No evidence exists that implants with higher price or newer technology have better clinical outcomes compared with standard or traditional implants.12 Therefore, newer technology should be adopted on the basis of evidence of cost-­effectiveness or the solution of a documented clinical problem not addressed by current technology.

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surgeon. The implants were assigned to demand function categories based on an implant’s expected capacity to manage the patient’s predicted demand. This program was used in primary TKA. The use of all-polyethylene tibial components in lower-demand categories afforded the greatest cost savings. A follow-up study assessed the use of a clinical pathway and the TKA implant standardization program as a regulator of resource utilization and hospital costs for TKA.6 The hospital cost, adjusted for medical inflation, was reduced 19%, whereas short-term patient outcome remained unaffected. A similar program was successful in decreasing THA hospital costs. To further decrease the price of orthopaedic implants, the Lahey Clinic developed a Single Price/Case Price Purchasing Program13 to eliminate potential conflicts between hospital administrators and surgeons concerning the price and selection of TJA implants. The vendor provided a single price for knee implants for every case irrespective of the implant used. The cost of knee implants decreased 23% without switching vendors. The vendor offered a price based on 3 years of historical implant selection data. Similar findings were reported for THA implants. The cost of revision arthroplasty has been found to be more difficult to regulate than the cost of primary TJA. Revision arthroplasty procedures are not suitable for a demand-matching system because of substantial differences in case severity and implant requirements. Applying cost reduction strategies to revision TJA implants will be challenging; however, implant systems are now available with fewer options, less complicated instrumentation, and lower cost. Whether these revision implant systems will deliver value to patients is still undetermined. Pain Management Postoperative pain can affect hospital stay, patient satisfaction, postsurgical rehabilitation, and a range of other clinical and administrative outcomes.14 The emergence of procedure-specific multimodal pain management has been one of the most important advances in hip and knee arthroplasty. The goal of multimodal pain management is to allow accelerated postoperative recovery while reducing the use of parenteral narcotics with the side effects of nausea, pruritus, constipation, delirium, and urinary retention. Multimodal preemptive analgesics are important adjuncts in pain management for patients undergoing TJA. The average length of hospital stay for patients in the preemptive analgesia group was 2.74 versus 3.28 days for patient-controlled analgesia in patients undergoing TJA.15 Patients in the patient-controlled analgesia group used substantially more intravenous morphine (17.7 versus

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7.2 mg) and experienced a threefold increase in nausea. In addition, those in the patient-controlled analgesia group were twice as likely to miss therapy and almost two times more likely to be discharged to an extended care facility. The use of preemptive oxycodone and a selective ­cyclooxygenase-2 inhibitor decreased postoperative narcotic requirements and increased participation in rehabilitation. In addition, patients who received preemptive analgesics had decreased hospital length of stay and reduced likelihood of discharge to a skilled nursing facility.15 To facilitate rapid recovery after TJA, a single-dose spinal anesthetic is preferred to avoid the complications of other neuroaxial anesthetics such as hypotension, urinary retention, poor muscle control, and delayed mobilization.16 Postoperatively, peripheral nerve blockade has become widely available for inclusion in multimodal regimens, but it is costly and has some important limitations, including an increased incidence of falls, inefficient use of the operating room, muscular weakness, and associated delays in physical therapy and rapid rehabilitation.14 Recently, periarticular injection of anesthetic and analgesic medications has gained importance and appears to offer comparable benefits to nerve blocks in joint arthroplasty without the limitations associated with peripheral motor blockade. The benefits of local periarticular injection are that it is simple to administer, surgeon directed, and allows an infiltration of anesthetic directly into the pain source.16 Ropivacaine-based periarticular injections were compared with peripheral nerve blocks (continuous femoral and single-injection sciatic) and both methods were found to be equally effective in controlling postoperative pain, but the patients who underwent periarticular injection had a shorter length of stay and decreased peripheral nerve dysesthesia.17 Another study that compared postoperative epidural analgesia with periarticular injection after TKA with spinal anesthesia found that patients who underwent periarticular injection had better postoperative pain relief, earlier recovery of knee flexion, and a lower incidence of postoperative nausea.18 Optimizing these parameters is important when trying to enable rapid recovery after TJA. The use of liposomal bupivacaine as a longer acting local anesthetic after TJA remains controversial and depends greatly on technique.19 Although some studies have indicated that liposomal bupivacaine decreases narcotic use and results in earlier achievement of physiotherapeutic milestones,19 the cost effectiveness of liposomal bupivacaine is unknown and is currently being studied.19

© 2017 American Academy of Orthopaedic Surgeons

Chapter 5: Economics and Cost Implications of Total Hip and Total Knee Arthroplasty

Table 1

Bundled Payment for Care Improvement Program Models Type

Description

Model 1

Retrospective payment for acute hospitalization covering Medicare Part A services

Model 2

Retrospective payment for entire episode of care (72 hours preoperative to 90 days postoperative) covering Medicare Part A and Part B services

Model 3

Retrospective payment for the period after hospitalization covering Medicare Part A and B services

Model 4

Prospective payment for acute hospitalization

Revision Surgery

Bundled Payments and Alternative Payment Models Traditionally, TJA services have been reimbursed with the fee-for-service model, which incentivizes the delivery of health care services in volume without much regard for quality and outcomes related to those services.22 However, financial challenges have shifted the focus to creating more value for the money allocated to TJA services and these new measures strive to reward the delivery of

© 2017 American Academy of Orthopaedic Surgeons

1: Hip and Knee

In recent years, the number of revision TJAs has increased, which is most likely a result of the increasing prevalence of primary TJA, expansion of indications to younger patients, more high-demand patients, and an increasing presence of patient factors such as obesity and diabetes.20 From 2006 to 2010, 23% and 40% increases in the number of hospitalizations were noted in patients undergoing revision THA and TKA, respectively.20,21 The reasons for revision TJA are mostly attributed to mechanical loosening and periprosthetic joint infection.20 The differences in resource utilization between THA and TKA were analyzed, including length of stay and cost.20 Periprosthetic joint infection and mechanical loosening were the most common indications for revision TKA, and dislocation and mechanical loosening were the most common indications for revision THA.20 Periprosthetic joint infection and periprosthetic fracture were associated with the greatest length of stay and costs for revision THA and TKA.20 The mean (± SD) length of stay was 4.8 ± 10.5 days for revision TKA and 5.8 ± 14.0 days for revision THA.20 The mean (±SD) hospital cost was $23,130 ± $36,643 for revision TKA and $24,697 ± $40,489 for revision THA.20 The study concluded that the revision burden for length of stay and hospitalization costs for THA is greater than that for TKA, but revision costs varied widely for both procedures.

high-quality care with improved outcomes. In 2011, the CMS created a Bundled Payment for Care Improvement (BPCI) initiative that focused on high-quality coordinated care that is outcome based.23,24 BPCI Organization Through the BPCI initiative, hospitals are paid one standard predetermined sum for an all-inclusive episode of care, or “bundle,” that can begin a certain time before an episode and continues for an established length of time after surgery. For TJA, the episode includes preoperative services 72 hours before surgery, inpatient services including surgery and postoperative care for a period of 30, 60, or 90 days from surgery.25 In this risk-sharing model, the healthcare provider is responsible for all care episodes within the at-risk postoperative period, including readmissions, without any additional reimbursement. Under this program, if the total costs of all services rendered in that episode are less than the bundled payment, the provider is entitled to the remainder. However, if the costs exceed the bundled payment target price, the provider will sustain a financial loss. The bundled care model incentivizes high-quality care with the goal of reducing readmissions and improving cost effectiveness.2 This alternative payment model will also shift a higher burden of costs to the provider in cases where patients have complications, require extended post–acute care, are readmitted, or require repeat procedures within the 90-day postoperative period after the index procedure.24 In addition to risk sharing, CMS also specifically authorizes gain sharing with stakeholders, with the idea that healthcare providers should be rewarded for restructuring their services to become more coordinated and cost effective.24 Gain sharing can vary depending on the negotiations between hospitals, surgeons, other episode initiators or stakeholders. The American Association of Hip and Knee Surgeons Bundled Payment Task Force advises that for gain-sharing arrangements, a specific baseline should be used to measure cost savings and quality

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measurements.24 Also, hospitals and surgeons must look beyond just implant-related costs to focus on streamlining the entire episode of care to maximize the benefits of the BPCI model.24 There are four models of BPCI currently being tested (Table 1).

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Results of BPCI in TJA Early findings were published on BPCI model 2 for a 90-day TJA episode of care at an urban, academic, orthopaedic specialty hospital.23 In the first year of the program, the average length of hospital stay for 721 patients decreased from 4.27 to 3.53 days. Discharge to inpatient facilities for rehabilitation also decreased from 65% to 43%. The total 90-day readmission rate was 11%. Readmissions from a facility were higher (13.7%) when compared with readmissions from home (9.0%). Medicare costs were reduced by up to 10% using the BPCI model.23 Infrastructure costs and the costs of implementing the program were not included in these calculations.23 The implementation of clinical care pathways and intensive care management services for TJA patients to improve efficiency and quality of care were important factors in generating cost reductions in BCPI.24 After year 1 of the BCPI program, an unacceptably high 90-day readmission of 11% was reported.26 Ninety percent of patients requiring readmission had at least one modifiable risk factor, which could have been optimized before surgery, and 50% of patients had two or more.26 Therefore, a risk factor stratification and modification program (the Perioperative Orthopaedic Surgical Home) designed to delay surgery in high-risk patients with potentially modifiable risk factors was instituted as a voluntary program for the surgeons involved in BPCI.27 Preliminary results demonstrated that readmission rates have been lowered from 15% in 2009 and 17% in 2011 to 11% at 90 days in 2013. The average length of stay decreased from 4.27 to 3.58 days and discharge to inpatient post– acute care facilities decreased from 71% to 44%.23 Across all model 2 episodes, the percentage of BPCI patients discharged to a post–acute care facility declined from 66% to 47%. Overall, the largest relative declines in payments occurred during the anchor hospital stay (consistent with reduced length of stay) and for physician evaluation and treatment visits.28 Unless a shift occurs in legislative mandate, alternative payment models are expected to continue to displace fee-for-service models over the next several years. Reducing Readmissions Alternative payment models are based on a risk-sharing system in which the health care provider and institution are compensated based on outcome for the entire “episode

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of care.” The episode can include inpatient services such as surgery and postoperative care for a period of up to 90 days following surgery. The at-risk postoperative period under BPCI includes readmissions, which are usually unplanned after TJA procedures. The initiator of the episode is responsible for all related costs within the agreed-on postoperative period, including readmissions, without any additional reimbursement.24,25 Reducing readmissions involves managing preoperative comorbidities that are associated with postoperative complications, which can be surgical and medical in nature. Providers must be able to select appropriate patients for TJA and identify high-risk patients and potentially modify risk factors that can be associated with worse outcomes. This selection process has obvious ethical implications because some patients may need to delay surgery until their health status is optimized. Short-Term Readmissions Healthcare providers must understand the nuances of the risk-sharing model focused on an episode of care. The cost burden of 30-day readmissions after primary and revision THA and TKA procedures was studied at a high-volume orthopaedic subspecialty hospital.29 Using a hospital database for primary and revision TJA procedures performed from 2009 to 2012, direct costs were obtained for each unplanned admission along with the total Part A Medicare payments. The 30-day readmission rate was 2.4 per 100 cases for primary TJA, 9.5 per 100 cases for revision THA, and 11.9 per 100 cases for revision TKA. The mean cost for readmission after primary THA and TKA was $17,103 and $13,008, respectively. The mean cost of readmission was $27,272 per case following revision THA and $29,893 per case following revision TKA. The readmission cost burdens per admission were 4.3% for THA, 2.8% for TKA, 8.3% for revision THA, and 11.9% for revision TKA. The three primary causes for readmission following TJA are wound complications, surgical site infections, and medical problems.30-32 Readmission risk is related to a patient’s severity of illness (SOI) and preoperative comorbidities. The readmission burden was stratified by SOI using the All Patients-Refined–Diagnosis-Related Group (APR-DRG) severity classification system.25 The APRDRG-SOI system has four categories of severity: minor, moderate, major, and extreme.31 Among 2,026 patients, the readmission rate was as low as 2.6% for patients with moderate SOI and as high as 26.1% for patients with extreme SOI. The average readmission costs were directly proportional to the SOI scale, with $12,781 for minor SOI, $17,575 for moderate SOI, $19,120 for major SOI, and $21,216 for extreme SOI. The readmission

© 2017 American Academy of Orthopaedic Surgeons

Chapter 5: Economics and Cost Implications of Total Hip and Total Knee Arthroplasty

Long-Term Readmissions A study that compared the 30-day and 90-day readmission data at a tertiary care urban hospital reported that surgical reasons accounted for slightly more than onehalf of overall readmissions.34 However, the study also reported that medical reasons for readmissions included problems such as cardiac complications, pulmonary complications, and venous thrombosis, which became more important factors in the 90-day postoperative period. The authors found that age (younger than 50 years and older than 80 years), Medicare or self-payer status, coronary artery disease, diabetes mellitus, weight (body mass index less than 18.5 kg/m 2 and greater than 30 kg/m2), and increased length of hospital stay (more than 5 days) were associated with substantial readmissions in the 90-day period.34 Similar findings have been reported in other studies.33,35 One study reported a direct correlation between increasing SOI and increasing costs of TJA-related readmissions.35 Patients who are transferred from rehabilitation facilities or outside hospitals tend to have higher categories of SOI and are more likely to be associated with higher readmission costs than patients who do not originate from such facilities.35 One study evaluated readmissions, revisions, infections, and hospital resource use in the first year after

© 2017 American Academy of Orthopaedic Surgeons

TJA.36 The study also examined hospitalization rates before elective TJA and reported that 12.9% of patients undergoing elective THA and 10.2% of patients undergoing elective TKA were hospitalized in the year before their index surgery. Hospitalizations increased to 14.8% of patients undergoing elective THA and 15.5% of patients undergoing elective TKA patients in the year following surgery, indicating 15% and 52% increases, respectively. Patients undergoing emergency THA (usually hip fractures treated using a prosthesis) were the most resource intensive: 26.7% having hospital admissions before THA and 27.8% readmissions in the year after surgery. For all patients, the most common reason for readmission was an implant-related complication followed by complications associated with the procedure. However, for patients undergoing emergency THA, the second most common reason for readmission was cardiac complications. Revision surgery within 1 year was 1.3% for patients undergoing elective surgery and 2.0% for patients undergoing emergency surgery. Most commonly, THA cases were revised for mechanical complications and TKA cases were revised for infections. In addition, a 2015 study showed that TKA revision has an 8.5% higher rate and THA revision has a 3.4% higher rate of repeat procedures such as irrigation and débridement or modular components exchange in the 90-day postoperative period. CMS does not proportionately compensate surgeons for the increased time and effort associated with performing revision TJA.37 The current reimbursement model makes it challenging for surgeons to provide revision TJA services to patients.5,6,37 Alternative payment models have not yet been applied to revision TJA.

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burden was also directly proportional to SOI with lower categories of SOI bearing a burden of approximately 4% to 5% and the extreme SOI group, with a readmission burden of 18.5%. In addition to risk factor modification, it is also essential to understand the preventable causes for readmissions. One study stated that, “for readmission rates to be a useful measure in assessing quality of care, they must capture only those readmissions that could have been prevented.”30 The major causes for readmission are infections, wound issues, workup of deep vein thrombosis and/or pulmonary emboli, and other medical complications.30,31,33 Current strategies to tackle infection prevention include timely, weight-based administration of preoperative antibiotics, prescreening and treatment of methicillin-resistant Staphylococcus aureus carriers, hepatitis C screening and treatment, ensuring adequate perioperative glucose control, creating hand hygiene programs, and maintaining normothermia and patient oxygenation.30,32 Another potential strategy aimed at reducing readmissions may involve outpatient deep vein thrombosis screening and treatment.

Summary The economics and cost implications of TJA are becoming increasingly challenging to understand, implement, and control. Creating value for patients undergoing arthroplasty requires efficient, integrated, and evidence-based clinical pathways that can deliver services to patients in a cost-effective manner. Intensive patient education, care management, optimization of health status, and alignment of stakeholder incentives will provide more value to patients undergoing TJA. Alternative payment models may help facilitate these care delivery improvements. ­Value-based purchasing will demand more attention to the cost-effective delivery of care in the future.

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Key Study Points

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• TJA is a successful, cost-effective procedure that requires an increasing amount of healthcare resources, but decreasing reimbursement and increased costs have put a financial strain on the healthcare system. • Cost analysis of TJA procedures across the United States shows a wide variation in the cost of surgery. • Medicare and Medicaid have implemented alternative payment models such as the Bundle Payment for Care Improvement Initiative and the Comprehensive Care for Joint Replacement, with the purpose of improving the quality of TJA care while reducing cost. • Various quality and cost effectiveness improvement measures include patient risk optimization, multimodal pain management, blood management protocols, implant cost negotiation, and care management initiatives. TJA in a value-based purchasing environment will require more attention to cost effective care delivery.

Annotated References 1. Bosco JA, Alvarado CM, Slover JD, Iorio R, Hutzler LH: Decreasing total joint implant costs and physician specific cost variation through negotiation. J Arthroplasty 2014;29(4):678-680. Medline  DOI More than $2 million was saved at the authors’ institution during the first year of the intervention to reduce implant costs. The study concluded the initiative is important to negotiate lower implant prices from vendors. Level of evidence: III. 2. Nordt J, Gregorian J, Connair M: As Medicare Costs Rise, Reimbursements Drop. 2015. Available at: http:// www.aaos.org/news/aaosnow/dec12/cover1.asp. Accessed October 6, 2015. This article discusses the increasing cost of medical practice along with decreasing reimbursement rates for practitioners, which lag behind inflation. The gap between operational costs and reimbursements for those procedures continues to widen. Level of evidence: V.

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4. Antoniou J, Martineau PA, Filion KB, et al: In-hospital cost of total hip arthroplasty in Canada and the United States. J Bone Joint Surg Am 2004;86-A(11):2435-2439. Medline 5. Rana AJ, Iorio R, Healy WL: Hospital economics of primary THA decreasing reimbursement and increasing cost, 1990 to 2008. Clin Orthop Relat Res 2011;469(2):355361. Medline  DOI This article discusses the concern of decreasing economic feasibility of hospitals providing THA. If hospital revenue continues to decrease and no innovations are associated with an increased cost, earning profit will prove difficult. Reform must occur to provide adequate reimbursements for hospitals and surgeons performing THA. Level of evidence: III. 6. Healy WL, Iorio R, Ko J, Appleby D, Lemos DW: Impact of cost reduction programs on short-term patient outcome and hospital cost of total knee arthroplasty. J Bone Joint Surg Am 2002;84-A(3):348-353. Medline 7. Kocher MS, Erens G, Thornhill TS, Ready JE: Cost and effectiveness of routine pathological examination of operative specimens obtained during primary total hip and knee replacement in patients with osteoarthritis. J Bone Joint Surg Am 2000;82-A(11):1531-1535. Medline 8. Schwarcz TH, Matthews MR, Hartford JM, et al: Surveillance venous duplex is not clinically useful after total joint arthroplasty when effective deep venous thrombosis prophylaxis is used. Ann Vasc Surg 2004;18(2):193-198. Medline  DOI 9. Bozic KJ, Morshed S, Silverstein MD, Rubash HE, Kahn JG: Use of cost-effectiveness analysis to evaluate new technologies in orthopaedics. The case of alternative bearing surfaces in total hip arthroplasty. J Bone Joint Surg Am 2006;88(4):706-714. Medline  DOI 10. Metz CM, Freiberg AA: An international comparative study of total hip arthroplasty cost and practice patterns. J Arthroplasty 1998;13(3):296-298. Medline  DOI 11. Suter LG, Paltiel AD, Rome BN, et al: Placing a price on medical device innovation: The example of total knee arthroplasty. PLoS One 2013;8(5):e62709. Medline  DOI This study reported that new technology is associated with a premium cost. Innovative implants must decrease actual TKA failure by 50% to 55% to be considered cost effective. Level of evidence: III.

3. BlueCross BlueShield: A Study of Cost Variations For Knee And Hip Replacement Surgeries In The U.S. Blue Health Intelligence; 2015:5-9. Available at: http://www.bcbs.com/ healthofamerica/BCBS_BHI_Report-Jan-_21_Final.pdf. Accessed October 30, 2015.

12. Iorio R, Healy WL, Kirven FM, Patch DA, Pfeifer BA: Knee implant standardization: An implant selection and cost reduction program. Am J Knee Surg 1998;11(2): 73-79. Medline

This survey conducted by one of the nation’s largest insurance companies analyzes the costs of orthopaedic procedures across the United States. The average total costs of TKA and THA in various cities are listed and compared. Level of evidence: V.

13. Healy WL, Iorio R, Lemos MJ, et al: Single price/case price purchasing in orthopaedic surgery: Experience at the Lahey Clinic. J Bone Joint Surg Am 2000;82(5):607-612. Medline

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Chapter 5: Economics and Cost Implications of Total Hip and Total Knee Arthroplasty

14. Springer BD: Transition from nerve blocks to periarticular injections and emerging techniques in total joint arthroplasty. Am J Orthop (Belle Mead NJ) 2014;43 (10 suppl):S6-S9. Medline This study reviewed the efficacy of postoperative pain control using peripheral nerve blockade and bupivacaine liposome injection in both TKA and THA. Sciatic nerve block and bupivacaine liposome injection were compared and bupivacaine liposome injection resulted in a considerable reduction in pain scores following THA and TKA as well as 6 to 12 hours postoperatively. A substantial reduction was also reported in postoperative opioid use with bupivacaine liposome injection, and an overall cost reduction of both THA and TKA. Level of evidence: I.

16. Sculco PK, Pagnano MW: Perioperative solutions for rapid recovery joint arthroplasty: Get ahead and stay ahead. J Arthroplasty 2015;30(4):518-520. Medline  DOI This article reviewed the transition from a sick patient model to the well patient model for recovery following TJA. Controlling volume depletion, blood loss, pain, and nausea perioperatively results in a more rapid recovery. Level of evidence: III. 17. Spangehl MJ, Clarke HD, Hentz JG, Misra L, Blocher JL, Seamans DP: The Chitranjan Ranawat Award: Periarticular injections and femoral & sciatic blocks provide similar pain relief after TKA: a randomized clinical trial. Clin Orthop Relat Res 2015;473(1):45-53. Medline  DOI This study compared a commonly used combination of a continuous femoral block administered with a single-injection sciatic block with a periarticular injection (ropivacaine, epinephrine, ketorolac, and morphine) after TKA. Patients who received the periarticular injections had similar paint scores, shorter length of stay, reduced likelihood of peripheral nerve dysesthesia, and increased narcotic use on the day of surgery compared with peripheral blocks. Level of evidence: I. 18. Tsukada S, Wakui M, Hoshino A: Postoperative epidural analgesia compared with intraoperative periarticular injection for pain control following total knee arthroplasty under spinal anesthesia: A randomized controlled trial. J Bone Joint Surg Am 2014;96(17):1433-1438. Medline  DOI Traditionally, epidurals have been used for TKA but are associated with the risk of adverse effects; recent studies have reported fewer adverse effects associated with periarticular injection. Periarticular injection offers better postoperative pain relief, earlier recovery of knee flexion angle, and reduced incidence of nausea compared with epidural anesthesia. Level of evidence: I. 19. Yu SW, Szulc AL, Walton SL, Davidovitch RI, Bosco JA, Iorio R: Liposomal bupivacaine as an adjunct to postoperative pain control in total hip arthroplasty. J Arthroplasty 2016 [Epub ahead of print]. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

20. Kurtz SM, Lau E, Ong K, Zhao K, Kelly M, Bozic KJ: Future young patient demand for primary and revision joint replacement: National projections from 2010 to 2030. Clin Orthop Relat Res 2009;467(10):2606-2612. Medline  DOI 21. Kurtz S, Mowat F, Ong K, Chan N, Lau E, Halpern M: Prevalence of primary and revision total hip and knee arthroplasty in the United States from 1990 through 2002. J Bone Joint Surg Am 2005;87(7):1487-1497. Medline  DOI 22. Luft HS: Economic incentives to promote innova tion in healthcare delivery. Clin Orthop Relat Res 2009;467(10):2497-2505. Medline  DOI

1: Hip and Knee

15. Duellman TJ, Gaffigan C, Milbrandt JC, Allan DG: Multi-modal, pre-emptive analgesia decreases the length of hospital stay following total joint arthroplasty. Orthopedics 2009;32(3):167. Medline  DOI

Although the cost-effectiveness of liposomal bupivacaine is not yet determined, it has shown decreased narcotic use and earlier achievement of physiotherapy milestones after TJA in some studies. Level of evidence: I.

23. Iorio R, Clair AJ, Inneh IA, Slover JD, Bosco JA, Zuckerman JD: Early results of medicare’s bundled payment initiative for a 90-day total joint arthroplasty episode of care. J Arthroplasty 2016;31(2):343-350. Medline  DOI Medicare initiated a program in 2011 to introduce a payment model that would result in higher quality, more coordinated care at a lower cost to Medicare. With the implementation of this program, average length of stay decreased, discharges to inpatient facilities decreased, and readmission decreased slightly. Cost savings was evident. Level of evidence: III. 24. Froimson MI, Rana A, White RE Jr, et al: Bundled payments for care improvement initiative: the next evolution of payment formulations: AAHKS Bundled Payment Task Force. J Arthroplasty 2013;28(8suppl):157-165. Medline  DOI This study reported that the initiation of the bundled payment model has the potential to enhance quality and reduce cost, thereby increasing the value of the services administered. How providers can be successful in this new environment is detailed. Level of evidence: III. 25. Kiridly DN, Karkenny AJ, Hutzler LH, Slover JD, Iorio R, Bosco JA III: The effect of severity of disease on cost burden of 30-day readmissions following total joint arthroplasty (TJA). J Arthroplasty 2014;29(8):1545-1547. Medline  DOI The cost of TJA as well as all additional related medical costs for up to 90 days are bundled into one lump sum. In this study, 2,026 patients undergoing TJA were reviewed to analyze costs of readmission and readmission rate. Both increased as the severity of illness increased. Level of evidence: III. 26. Yu S, Garvin KL, Healy WL, Pellegrini VD Jr, Iorio R; Journal of the American Academy of Orthopaedic Surgeons: Preventing hospital readmissions and limiting the complications associated with total joint arthroplasty. J Am Acad Orthop Surg 2015;23(11):e60-e71. Medline  DOI

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This study reported that after the implementation of the BPCI Program at the NYULMC, the 90-day readmission rate of 11% was unacceptably high. The study also reported that 90% of patients requiring readmission had at least one modifiable risk factor that could be optimized preoperatively, and 50% of patients had two or more. These modifiable risk factors could further limit readmission rate. Level of evidence: III. 27. Boraiah S, Joo L, Inneh IA, et al: Management of Modifiable Risk Factors Prior to Primary Hip and Knee Arthroplasty: A Readmission Risk Assessment Tool. J Bone Joint Surg Am 2015;97(23):1921-1928. Medline  DOI

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This study created a readmission risk assessment tool (RRAT) to identify associations between total joint arthroplasty related readmissions and RRAT. Level of evidence: III. 28. Dummit L, Marrufo G, Marshall J, et al: CMS Bundled Payments for Care Improvement (BPCI) Initiative Models 2-4: Year 1 Evaluation & Monitoring Annual Report. Falls Church, VA, The Lewin Group, 2015. Available at https://innovation.cms.gov/Files/reports/BPCI-EvalRpt1. pdf. Across all Model 2 episodes, the percentage of BPCI patients discharged to a post–acute care facility declined from 66% to 47%, and the proportion discharged home remained steady. Although not significant, the largest relative declines in payments occurred during the anchor hospital stay (consistent with the reduced length of stay) and for physician evaluation and treatment visits. Level of evidence: III. 29. Bosco JA III, Karkenny AJ, Hutzler LH, Slover JD, Iorio R: Cost burden of 30-day readmissions following Medicare total hip and knee arthroplasty. J Arthroplasty 2014;29(5):903-905. Medline  DOI This study quantified the readmission burden of TJA as a function of reimbursement and readmission in a bundled payment model. Any decrease in hospital cost margins can make performing TJA economically unfeasible. Level of evidence: III. 30. McCormack R, Michels R, Ramos N, Hutzler L, Slover JD, Bosco JA: Thirty-day readmission rates as a measure of quality: Causes of readmission after orthopedic surgeries and accuracy of administrative data. J Healthc Manag 2013;58(1):64-76, discussion 76-77. Medline This analysis was stratified to determine the cause of readmission: 30% of readmissions were planned, and almost 60% were a result of infection. Nonsurgical complications accounted for 18.2% of the unplanned readmission. Level of evidence: III. 31. Shah AN, Vail TP, Taylor D, Pietrobon R: Comorbid illness affects hospital costs related to hip arthroplasty: Quantification of health status and implications for fair reimbursement and surgeon comparisons. J Arthroplasty 2004;19(6):700-705. Medline  DOI 32. Mehta S, Hadley S, Hutzler L, Slover J, Phillips M, Bosco JA III: Impact of preoperative MRSA screening

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and decolonization on hospital-acquired MRSA burden. Clin Orthop Relat Res 2013;471(7):2367-2371. Medline  DOI In this study, the prevalence of methicillin-resistant Staphylococcus aureus was determined at a specialty orthopaedic hospital before and after the implementation of a screening and decolonizing protocol. Protocol use decreased the prevalence density of methicillin-resistant S aureus. Level of evidence: III. 33. Husted H, Otte KS, Kristensen BB, Orsnes T, Kehlet H: Readmissions after fast-track hip and knee arthroplasty. Arch Orthop Trauma Surg 2010;130(9):1185-1191. Medline  DOI With new patient optimization strategies, length of stay has been successfully decreased overall in TKA and THA. Fast-track TJAs do not increase the rate of readmissions. Level of evidence: III. 34. Saucedo JM, Marecek GS, Wanke TR, Lee J, Stulberg SD, Puri L: Understanding readmission after primary total hip and knee arthroplasty: Who’s at risk? J Arthroplasty 2014;29(2):256-260. Medline  DOI The most common reasons for readmission were infection and procedure-related complications. However, risk factors such as coronary artery disease, diabetes, increased length of stay, underweight status, obese status, age older than 90 years or younger than 50 years, and Medicare were associated with an increased likelihood of readmission. Level of evidence: III. 35. Plate JF, Brown ML, Wohler AD, Seyler TM, Lang JE: Patient factors and cost associated with 90-day readmission following total hip arthroplasty. J Arthroplasty 2016;31(1):49-52. Medline  DOI Average surgical readmissions were more costly than medical readmissions. Costs of imaging, laboratories, medications, transfusions and hospital cost increased as SOI increased. Level of evidence: III. 36. Bohm ER, Dunbar MJ, Frood JJ, Johnson TM, Morris KA: Rehospitalizations, early revisions, infections, and hospital resource use in the first year after hip and knee arthroplasties. J Arthroplasty 2012;27(2):232-237.e1, e1. Medline  DOI In this study, a 15% and 52% increase was reported in the hospitalization of patients who underwent THA and TKA, respectively. The increased rehospitalization illustrates an incremental cost of 10% over the index hospital stay. Level of evidence: III. 37. Tokarski AT, Deirmengian CA, Lichstein PM, Austin MS, Deirmengian GK: Medicare fails to compensate additional surgical time and effort associated with revision arthroplasty. J Arthroplasty 2015;30(4):535-538. Medline  DOI Revision TKA and THA are time and resource intensive. Practices undertaking revision surgery will see decreased reimbursements compared to practices focused on primary TJA. Patient access to physicians performing revision arthroplasty procedures may become challenging. Level of evidence: III. © 2017 American Academy of Orthopaedic Surgeons

Chapter 6

National Joint Registries Daniel J. Berry, MD  David G. Lewallen, MD  Fares S. Haddad, FRCS (Orth)

Abstract

Keywords: American Joint Replacement Registry (AJRR); arthroplasty; joint registries; National Joint Registry (NJR) for England; Wales; Northern Ireland; and the Isle of Man Introduction Daniel J. Berry MD

Registries for hip and knee arthroplasty have been used for 4 decades and have a profound and increasing effect on the clinical practice of total hip arthroplasty (THA) and

1: Hip and Knee

National joint registries can provide descriptive information about patients undergoing joint arthroplasty, including survivorship rates and outcomes data about joint arthroplasty based on patient, hospital, and implant factors. Registries also can provide information about the most common reasons for implant failure and associated complications. These data can provide a real-time feedback loop to all stakeholders—patients, surgeons, hospitals, payers, and implant manufacturers—that can lead to quality improvement. It is helpful to be aware of the current status and what has been learned from the American Joint Replacement Registry and the United Kingdom National Joint Registry. Registries have limitations, however; the most important limitation is that although they provide information about associations between outcomes and patient and implant factors, they cannot prove such associations as being causal.

knee arthroplasty. Registries come in many categories, including national registries, regional or state registries, institutional registries, and industry-based registries. Each type of registry has its own advantages, disadvantages, limitations, and applications. Registries are designed to enroll patients who have undergone joint arthroplasty and systematically collect data related to the patient, the procedure, and the outcomes of the procedure. Registries can provide many useful functions to both the orthopaedic community and patients. Registries can provide descriptive data about patients being treated with joint arthroplasty and the characteristics of the joint arthroplasties being used. This information provides real-time observations about the practice of joint arthroplasty. Registries can provide high-level data about the overall revision rate for hip and knee replacement and how demographic factors and generic implant characteristics affect rates of implant revision. Registries can provide information on the most common reasons for implant failure and the rates of the most common complications, thereby guiding thoughtful innovation aimed at solving real problems. Registries show how specific implants are performing (thereby guiding implant selection) and also serve as a trigger to identify implants that are not performing well.1 Registries can examine associations between specific patient characteristics and comorbidities and the risks of adverse outcomes, which can result in risk stratification. Increasingly, registries may collect global or joint-specific patient-reported outcome measures or clinical joint scores that provide a more nuanced understanding of the results of joint arthroplasty compared with revision as the main end point. In all these

Dr. Berry or an immediate family member has received royalties from DePuy; serves as a paid consultant to DePuy; has received research or institutional support from DePuy; and serves as a board member, owner, officer, or committee member of the American Joint Replacement Registry, the Hip Society, the International Hip Society, and the Mayo Clinic Board of Governors. Dr. Lewallen or an immediate family member has received royalties from Mako/Stryker, Pipeline, and Zimmer; serves as a paid consultant to Link Orthopaedics and Zimmer; serves as an unpaid consultant to Ketai Medical Devices; has stock or stock options held in Acuitive and Ketai Medical Devices; and serves as a board member, owner, officer, or committee member of the American Joint Replacement Registry and the Orthopaedic Research and Education Foundation. Dr. Haddad or an immediate family member has received royalties from Corin, Matortho, and Smith & Nephew; serves as a paid consultant to Smith & Nephew and Stryker; and has received research or institutional support from Smith & Nephew.

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roles, registries provide a feedback loop to stakeholders (patients, surgeons, hospitals, and implant manufacturers), which allows stakeholders to compare relevant outcomes with benchmarks and subsequently make choices or changes that improve the results of joint arthroplasty.2 Registry End Points

1: Hip and Knee

The most common registry end point has been revision surgery. Revision is a hard end point that is not subject to interpretation. However, the way in which revisions are categorized from one registry to another varies considerably, which has consequences for what can be learned.3,4 One registry may combine revisions for osteolysis with revisions for aseptic loosening, whereas another may consider the two as separate categories. More specific categorization may not only be valuable for interpreting results but also increase the risk of miscategorization at the time of data entry. Many registries cannot identify which of several implant parts in a joint arthroplasty have failed and required revision. Therefore, separating failures such as aseptic loosening for a specific implant (for example, acetabular versus femoral components of a THA) may not be possible. Because many registries consider only revision as the end point, some important complications may not be identified. If only infections that result in revision are captured, then all infections treated without implant revision are overlooked. If only hip dislocations resulting in revision are captured, all other dislocations are not identified.5 Some registries collect clinical outcome scores, including patient-reported data, which can provide valuable information about the results of surgery that is more nuanced than just revision as an end point.6 However, for such outcome measures to be useful for comparison purposes, considerable patient information is needed to allow risk stratification. Registries are increasingly trying to gain more detail about patient characteristics, including comorbidities before surgery (so-called level 2 data) to allow the development of better risk stratification models. Limitations of Registries Registries can provide big-picture information about what is being done and the results being produced. They also can provide associations between outcomes and patient and implant characteristics. However, it is important to understand that such associations do not necessarily arise from causality, and confounding variables often are present.7 Registries are subject to selection bias; that is, some procedures or implants may be used disproportionately

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in certain types of patients or by certain surgeons, with better or worse results, which results in bias in outcomes. Registries primarily reporting revision as an end point will not pick up failures that do not lead—or have not yet led—to revision. This can affect results, particularly if revision surgery is delayed in a systematic fashion, such as in countries with long waiting lists for such surgical procedures. Registries also are limited by the data collected for each registry. For example, a lack of specificity about what part of an implant has failed and the reasons for that failure may limit the conclusions that can be drawn. National registries have the advantage of extremely large numbers, but for practical reasons, they cannot collect data at the level of detail of some institutional registries. For this reason, institutional registries that collect detailed surgical patient data often can address different questions compared with those of national registries. Likewise, many questions cannot be answered by a registry; therefore, well-designed randomized controlled trials, case-control studies, and detailed case series complement the work of registries.8 Data from registries may provide information that results in hypothesis generation that can be proven or refuted by subsequent prospective or more in-depth studies. Trends in Registries Registries allow surgeons and hospitals to compare their individual results with large national cohorts. For this comparison to be meaningful, the cohorts must be risk stratified. Risk stratification for different end points is complex and is still being optimized. To perform good risk stratification, registries are increasingly collecting more data about medical comorbidities, patient characteristics, and orthopaedic factors that can influence hip and knee replacement outcomes. Patient-reported outcome measures and joint-specific outcome measures are being collected more commonly as surgeons, payers, regulatory agencies, and patients seek more nuanced measures of the results of joint arthroplasty versus only revision. Although these measures have great value, they are time consuming and expensive to collect; simplifying how these measures are collected, reducing the number of questions to minimal necessary datasets, and identifying the circumstances under which outcome measures are most valuable to collect is an ongoing effort. Each registry has its own advantages and d ­ isadvantages. Merging or sharing data between different registries can provide synergies.9 Currently, the International Society of Arthroplasty Registries is working to standardize terminology and define minimal collected datasets. These efforts may allow collaboration of registries to evaluate

© 2017 American Academy of Orthopaedic Surgeons

Chapter 6: National Joint Registries

serious problems that arise infrequently, identify concerns with respect to specific implants or procedures earlier, and confirm or deny observations reported from just one registry. National Joint Registries David G. Lewallen, MD

The American Joint Replacement Registry Background

Current Status

As of March 2016, the AJRR had gathered level 1 data on more than 365,000 procedures performed by more than 4,600 surgeons as reported by 670 participating hospitals located in all 50 states. Level 1 data represent the minimum information required on all cases for participation in the AJRR and include details on the patient, the procedure, the hospital, the surgeon, and the implant

© 2017 American Academy of Orthopaedic Surgeons

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

1: Hip and Knee

The American Joint Replacement Registry (AJRR) is a not-for-profit 501(c)(3) tax-exempt organization that was established to collect data on THA and total knee arthroplasty (TKA) performed in the United States to improve the quality of care. It is the result of a multiple stakeholder collaborative effort by the American Academy of Orthopaedic Surgeons; the American Association of Hip and Knee Surgeons; the Hip Society; the Knee Society; hospitals within the American Hospital Association; individual participating institutions, health insurance plans, and medical device manufacturers; and both volunteer and direct financial contributions from individual orthopaedic surgeons. All stakeholders and the public are represented on the 15-person board of directors, which is responsible for the AJRR’s strategic direction and oversight of its activities and operations. The goal of the AJRR is to capture data on more than 90% of all hip and knee arthroplasties performed in the United States, while also developing the comprehensive data needed to enhance orthopaedic quality of care, thereby improving patient outcomes and safety, reducing costs, and advancing orthopaedic science and bioengineering. The American Academy of Orthopaedic Surgeons provided initial support for the AJRR. After formalizing the multiple-stakeholder model, the AJRR evolved to include varying levels of support from virtually all the participating stakeholder groups. It is currently evolving into an organization that will be mainly supported by subscriptions or software licensing fees, which are currently paid by a subset of hospitals and, more recently, some physician practice groups (and soon to include individual surgeons) desiring on-demand access and display of their own data benchmarked to the national sample.

itself to allow long-term tracking of implant survivorship. Level 2 data on comorbidities and complications and level 3 data on patient-reported outcomes also are being collected by the AJRR on an expanding subset of patients from hospitals that have elected to collect and report these data. In the most recent AJRR annual report published in November 2015, information on the cumulative experience from 2012 through the end of 2014 was summarized. This report presented data on hip and knee arthroplasty procedures of all types, totaling more than 225,000 cases through the end of 2014. These procedures were performed by more than 2,300  surgeons located in all 50 states from institutions that represented the full range of hospital types, sizes, and locations. Patients undergoing arthroplasty in this large US sample were predominantly female (56.8% of hips, 61.6% of knees), with a mean age of 67.7 years for hip arthroplasty and 66.1 years for knee arthroplasty. Thus, almost one-half of all procedures in the United States were performed in individuals older than 65 years and were not well represented in studies solely of Medicare datasets. In this sample of the national experience, osteoarthritis was the predominant diagnosis prompting arthroplasty. Rheumatoid arthritis was indicated in fewer than 1% of these procedures, likely related to advances in the medical management of inflammatory arthropathies during the past decade. In the initial few years of any registry operation, data available are mainly descriptive, pending longer-term follow-up and survivorship data on implant performance (which can be further studied by hospital, surgeon, surgical technique, and patient factors). Another example of important descriptive information on the national experience is the most recent annual report that demonstrated that femoral neck fracture accounts for more than 1 in 10 hip arthroplasties currently performed in the United States. Short-term shifts in practice patterns also can be documented. For surface replacement arthroplasty, which once widely performed, the percentage decreased to fewer than 0.5% of hip procedures between 2012 and 2014 and was limited to a handful of hospitals and surgeons. Implant-specific information and patterns of use of specific implant technology can be documented as such technology evolves in the initial years of a registry such as the AJRR, which is shown by the example of ceramic head use in THA (Figure 1). The relative percentage of ceramic versus cobalt-chromium heads used in hip arthroplasty in the United States from 2012 to 2014 can be tracked by year (Figure 1). Ceramic head usage also can be shown to be biased toward younger patients, comprising most arthroplasties in those younger than 60 years and diminishing usage

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1: Hip and Knee

Figure 2

Figure 1

Bar graph of ceramic versus cobalt-chromium femoral head usage between 2012 and 2014. (Adapted with permission from the American Joint Replacement Registry: Annual Report, 2014. Rosemont, IL, American Joint Replacement Registry, 2015, pp 14-15.)

with each decade of patient age thereafter (Figure 2); however, the percentage of older patients receiving a ceramic femoral head has grown each year since 2012. Data on knee arthroplasties has shown that these procedures are performed almost exclusively for osteoarthritis, with tricompartmental replacement and posterior-­stabilized components used in most primary knee arthroplasties. Cruciate-retaining implants were used in fewer than one-third of the procedures. Revision burden also can be tracked by a national registry effort such as AJRR, and it is defined as the percentage of total joint arthroplasty cases performed per year that were revisions of prior implants. Revision burden is one measure of the success and long-term durability of these procedures. In the AJRR annual report, the revision burden was 10% of all hip arthroplasties performed annually; for knee arthroplasties, the revision burden was slightly lower, at 8.1% of all knee arthroplasties per year. The AJRR is actively expanding data collection from hospitals with comprehensive level 2 (comorbidity and complications) and optional level  3 (patient-reported outcome measures) data available for local data analysis needs to support the extramural payment and quality reporting needs of institutions and providers. A surge in interest and participation in the AJRR has followed the introduction of incentives by payers and certifying bodies for registry participation as a quality improvement indicator. The AJRR currently provides a robust foundation for

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Line graph of ceramic femoral head usage by patient decade of life (N = 35,956). (Reproduced with permission from the American Joint Replacement Registry: Annual Report, 2014. Rosemont, IL, American Joint Replacement Registry, 2015, pp 14-15.)

the collection of hospital- and provider-specific information that can be benchmarked against national data. Such data will become increasingly valuable in the next several years with the addition of risk-adjusted implant survivorship and complication data, helping to further drive improvements in care for patients undergoing arthroplasty.10 The United Kingdom and International Experience Fares S. Haddad, FRCS (Orth) Background

Hip, knee, ankle, elbow, and shoulder joint arthroplasties have become common and highly successful procedures that bring many patients improved mobility and pain relief. The National Joint Registry (NJR) for England, Wales, Northern Ireland, and the Isle of Man has been in existence for more than a decade and was developed based on the success of the Scandinavian registries. During the same time period, the Australian registry developed a useful output of information from the Southern Hemisphere, and the hope is that multiple registries will be developed worldwide, for not only hip and knee arthroplasty but also other orthopaedic subspecialties, and harmonized in such a way that they can be assessed together and information gleaned across cohorts and populations.11,12 Registry data are now clearly a valuable part of the orthopaedic surgeon’s armamentarium. In orthopaedic medicine, physicians have significantly relied on expert opinion and the outcome of case series to guide management. More recently, physicians have increasingly recognized the importance of prospective randomized studies, but these are expensive and not always practical, focusing on specific refined questions. Registry data and

© 2017 American Academy of Orthopaedic Surgeons

Chapter 6: National Joint Registries

The Remit of NJR

The NJR collects information on joint arthroplasty surgery and monitors the performance of joint arthroplasty implants. It was established in 2002 by the UK Department of Health. The registry helps monitor the performance of implants and the effectiveness of different types of surgery. It currently collects data on all hip, knee, ankle, elbow, and shoulder joint arthroplasties across the National Health Service and the independent healthcare sector and has more than 1 million procedures registered.28 The six goals of NJR are as follows: (1) Monitor in real time the outcomes achieved by brand of prosthesis,

© 2017 American Academy of Orthopaedic Surgeons

hospital, and surgeon and highlight where these fall below an expected performance to allow prompt investigation and support follow-up action; (2) inform patients, clinicians, providers, and commissioners of healthcare, regulators, and implant suppliers of the outcomes achieved in joint arthroplasty surgery; (3) showcase variations in outcomes achieved across surgical practices to inform best practice; (4) enhance patient awareness of joint arthroplasty outcomes to better inform patient choice and patients’ quality of experience by engaging with patients and patient organizations; (5) support evidence-based purchasing of joint arthroplasty implants for healthcare providers to support quality and cost effectiveness; and (6) support suppliers in the routine after-market surveillance of implants and provide information to clinicians, patients, hospital management, and the regulatory authorities.

1: Hip and Knee

studies add great value because they provide information regarding the entire population.13 Registry analysis helps identify trends and potential problems. The great advantages of any registry are that registries are cross-sectional across an entire population and provide objective primary data on what happens to patients or implants and procedures. The registries also provide a real-time view because the data come from more than just major centers or design surgeons. In effect, the data are a real-time check of the generalizability of a procedure or an implant. It also has been shown that feedback improves performance.14-18 If a registry has good compliance and produces clean validated data, the optimal treatment modalities (approaches, implants, or procedures) can be identified. Great learning and research potential is possible for the entire community, at potentially large savings for healthcare providers, which is predicated on clear, impartial, statistically sound, and unbiased interpretation. Such potential has been effectively shown in the Scandinavian model.19-23 Registries have great potential for identifying early failure of a new implant or technique. Registries also can be used to identify a poor performer within a subgroup, for example, a certain type of knee replacement or hip resurfacing. Registries also can identify outlying implants or surgeon performance, which should generate questions related to why outliers are occurring and what, if anything, should be done.24-26 The NJR has an Outlier Committee that examines both outlier surgeon and implant performance. This system effectively alerts surgeons and units to potential problems with performance. The data can be checked locally, and changes in practice can be made. This system has improved performance and outcomes for both surgeons and patients. The process also is confidential initially; although it is perhaps important that such evaluations and their outcomes are within the public domain, the process itself does not need to be revealed publically.27

Orthopaedic Registries and Data Interpretation

The NJR is a powerful resource that can contribute to research into the full range of biologic, mechanical, clinical, economic, and social factors influencing the outcome of joint arthroplasty. The data also can help establish the effect of joint arthroplasty on the well-being of patients and the general population. However, problems and challenges exist with some registries. Many have limited data capture and data quality, which makes data interpretation and use difficult. Registries are now a critical part of surgeon decision making, but it is important to interpret registries given that they are not always necessarily relevant to individual practice and do not prove causation. They merely provide a means for analysis and to generate hypotheses. Registries also need to be studied longitudinally. Certain aspects, such as cementation of the femoral stem that makes one type of implant, the cemented femoral stem, might look much better than aspects for a noncemented stem in the first decade, but follow-up during the second decade may show that noncemented arthroplasty comes to the fore later.29,30 Any dataset within a registry needs to be interpreted in the light of confounders. For example, using registry data to promote one approach or anesthetic technique over another needs to somehow control for the type of patients in each group and some form of selection bias.31,32 An important issue is that the end point in registries is revision, not clinical outcome or function. Because of a large bias toward revision as the key end point for any arthroplasty, it is difficult to say whether a procedure or an implant that has functioned well for 10 years should be discarded in favor of one that functions poorly but survives 10 or 15 years or longer because it is difficult to

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revise. Moreover, if the data are analyzed poorly, a single poor performer in a subgroup can negatively affect the remainder of the subgroup and skew the data. Registries are strongly affected by revision bias. Data can be either misinterpreted or overinterpreted, thus opening registries to inappropriate use by colleagues, industry, and politicians.32,33 Revisions and other complications also vary with case complexity and orthopaedic and medical comorbidity. Limitations in the accuracy of any inferred conclusions include difficulties in adjusting for case-mix complexity, inaccuracy of propensity scores, a lack of data validation, missing data, incomplete capture of preexisting covariates, limitations of Cox regression analysis, and inferring causation from observational data.34,35 One key issue is that registries are not sufficiently developed for patient-level analysis. They provide population data that are ideal for hypothesis generation. The findings from such data need to be tested in appropriately constructed studies. When circumstances determine that this is not possible, the data need to be interpreted for what they are and acted on appropriately. In the United Kingdom, NJR data are not owned by the profession, which creates a disadvantage. Data can be published without knowledge, agreement, or validation by the profession. Risks and Challenges

Although physicians are aware of the many potential benefits of registries, they continue to grapple with the difficulties that registry data can present. Recent information demonstrating that some retrieved metal-on-metal revision procedures were not incorporated into the NJR implants survival curve is concerning,3,36-40 and two recent articles highlighted missing data from the national registry.37,38 Such instances should be interpreted in light of ongoing initiatives to validate NJR data locally, setting up a more robust and centralized process to understand and evaluate the data in a more transparent way. Nevertheless, these studies raise questions about the potential use of NJR (and other registry) data and particularly about the publication of surgeon-level data. The headline outcome results of the NJR are similar to those of all other national registries. With 1.7 million entries, even 1,000 missing cases will have little effect. At the individual surgeon level, however, where the denominator may be only a few hundred procedures, the effect may be greater. Using parametric statistical techniques and standard deviations about a norm, to rank and compare surgeon performance, is problematic. There will always be a bottom 1%, 2%, 5%, and 10%. If these are removed, then the process starts again with a new bottom of 1%, 2%, 5%, and 10%. Such parameters may not be

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what the exercise is aiming to achieve. It would be a detriment if surgeons started avoiding the most complex cases. The data have not yet been validated, and in the first 10 years of the registry, data capture was inconsistent.37,38 The data to separate and control for orthopaedic and medical case mix complexity is inadequate and limited to age, body mass index, American Society of Anesthesiologists grade, and the use of bone graft. The dataset is incomplete: the national average is 92% complete; although some units have 100% compliance, several are much closer to 50%, which should raise concerns regarding any inferences made at individual surgeon-level reporting. It is fully appreciated that the NJR is getting better each year, but another 10 years may be necessary before the dataset is sufficiently validated and appropriately evaluated to consider the publication of surgeon-level data. The Future

The NJR recently celebrated its tenth anniversary and has registered more than 1.7 million procedures. Combined with other national registries, the NJR has had a huge effect on the practice of joint arthroplasty worldwide. Registries realize the epidemiologic goals of enhancing general awareness; supporting evidence-based practice; providing after-market implant surveillance; and monitoring outcomes achieved by brands of prosthesis, hospitals, and surgeons. Therefore, registries cater to the patients, clinicians, providers, and commissioners of healthcare, regulators, and implant suppliers. The ability to link registry data to patient-reported outcome measures as well as other population-based data sources enhances their usefulness for monitoring outcomes and trends. Registries, and the NJR in particular, have inherent disadvantages that limit the interpretation of the data made available by them. Compliance issues associated with any data collection and the reporting process limit the quality of the registry data. No robust system is in place to tackle confounding data and capture underreported data or unreported outcomes. Registries were set up to capture survival, but the ancillary data that have been collected are not validated. Caution must be exercised when using registries as high-level evidence. Registry-based study results cannot infer causative explanations. Any trend identified should be used to test hypotheses, not as a study conclusion. Focused studies also will be necessary to introduce new technology because registries only are surrogates to this process. The best registry data are complete, validated, and peer-reviewed and have good source data verification. Such data have systems in place to determine the appropriate research questions and methods to be used;

© 2017 American Academy of Orthopaedic Surgeons

Chapter 6: National Joint Registries

high-level database integration techniques and outputs are required to create important messages and result in practice change. Registries have an ongoing role. They will get improve as good practice is integrated across different medical societies. It is important that registries are used appropriately to avoid politically biased interpretations or poor health economic analyses. Ultimately, registries should help surgeons make their decisions by providing needed and desired data. Summary

Key Study Points • National joint registries can provide descriptive information about patients undergoing joint arthroplasty, survivorship rates, and outcomes data about joint arthroplasty based on patient, hospital, and implant factors. • Registries also can provide information about the most common reasons for implant failure and complications. • Data provide a real-time feedback loop to all stakeholders (patients, surgeons, hospitals, payers, and implant manufacturers), which can lead to quality improvement. • Registries have limitations, the most important of which is that they provide information about associations between outcomes and patient and implant factors, but they cannot prove that such associations are causal.

Annotated References 1. de Steiger RN, Miller LN, Davidson DC, Ryan P, Graves SE: Joint registry approach for identification of outlier prostheses. Acta Orthop 2013;84(4):348-352. Medline  DOI This article describes the methods used by the Australian Orthopaedic Association National Joint Registry to identify outlier prostheses.

© 2017 American Academy of Orthopaedic Surgeons

The authors examined the different needs of various stakeholders when using registry data. 3. Liebs TR, Splietker F, Hassenpflug J: Is a revision a revision? An analysis of national arthroplasty registries’ definitions of revision. Clin Orthop Relat Res 2015;473(11): 3421-3430. Medline  DOI This study compared the definitions of revision among registry reports and apply common clinical scenarios to these definitions. Revision, which is the most common end point used by arthroplasty registries, is not universally defined. This implies that some reoperations that are considered a revision in one registry are not considered a revision in another registry. Therefore, comparisons of implant performance using data from different registries should be performed with caution.

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National registries are becoming more common and are maturing. The data provided by these registries is having more beneficial effects on orthopaedic practices. The advantages and limitations of joint registries are important to understand when evaluating data.

2. Delaunay C: Registries in orthopaedics. Orthop Traumatol Surg Res 2015;101(1 suppl):S69-S75. Medline  DOI

4. Niinimäki TT: The reasons for knee arthroplasty revisions are incomparable in the different arthroplasty registries. Knee 2015;22(2):142-144. Medline  DOI Joint revisions are categorized differently in registries, which may result in some observed discrepancies in outcome results from different registries. 5. Devane PA, Wraighte PJ, Ong DC, Horne JG: Do joint registries report true rates of hip dislocation? Clin Orthop Relat Res 2012;470(11):3003-3006. Medline  DOI Dislocations not resulting in revision often were not captured in the New Zealand Joint Registry. 6. Patel J, Lee JH, Li Z, SooHoo NF, Bozic K, Huddleston JI III: Predictors of low patient-reported outcomes response rates in the California Joint Replacement Registry. J Arthroplasty 2015;30(12):2071-2075. Medline  DOI The critical factor in ongoing participation after surgery in patient-reported outcome reporting in the California Joint Arthroplasty Registry (now part of the American Joint Replacement Registry) was preoperative participation in survey collection. 7. Whitehouse SL, Bolland BJ, Howell JR, Crawford RW, Timperley AJ: Mortality following hip arthroplasty—inappropriate use of National Joint Registry (NJR) data. J Arthroplasty 2014;29(9):1827-1834. Medline  DOI The authors explored confounding variables in mortality reporting in the NJR. 8. Inacio MC, Paxton EW, Dillon MT: Understanding orthopaedic registry studies: A comparison with clinical studies. J Bone Joint Surg Am 2016;98(1):e3. Medline  DOI This article explains the complimentary nature of registry studies to randomized controlled trials and cohort studies. 9. Stea S, Comfort T, Sedrakyan A, et al: Multinational comprehensive evaluation of the fixation method used in hip replacement: Interaction with age in context. J Bone Joint Surg Am 2014;96(suppl 1):42-51. Medline  DOI

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The authors reported on collaboration between six national and regional joint registries to evaluate fixation in hip replacement. 10. American Joint Replacement Registry: Annual report 2014: Second AJRR annual report on hip and knee arthroplasty data. Available at http://www.ajrr.net/images/annual_reports/AJRR_2014_Annual_Report_final_11-11-15. pdf. Accessed July 10, 2016. 11. Malchau H, Porter ML: Editorial comment: 2014 meeting of the International Society of Arthroplasty Registers. Clin Orthop Relat Res 2015;473(11):3368-3369. Medline  DOI

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The authors summarized the output of a meeting of the International Society of Arthroplasty Registers and identified a need for registries to work together to collect comparable data. 12. Graves SE: The value of arthroplasty registry data. Acta Orthop 2010;81(1):8-9. Medline  DOI 13. Bedair H, Lawless B, Malchau H: Are implant designer series believable? Comparison of survivorship between designer series and national registries. J  Arthroplasty 2013;28(5):728-731. Medline  DOI Fifteen different hip and knee implant results published by designers were identified and compared with four national registries. Thirty-two percent of the comparisons performed demonstrated greater survivorship in the designer series compared with the registries, and 68% demonstrated no difference. Two implants accounted for most (12 of 16) of the discordances. 14. Hunt LP, Ben-Shlomo Y, Clark EM, et al; National Joint Registry for England and Wales: 45-day mortality after 467,779 knee replacements for osteoarthritis from the National Joint Registry for England and Wales: An observational study. Lancet 2014;384(9952):1429-1436. Medline  DOI The authors looked at NJR data for hip replacements between April 2003 and December 2011. Patient identifiers were used to link these data to the national mortality database and the Hospital Episode Statistics database. A secular decrease in mortality, from 0.56% in 2003 to 0.29% in 2011, occurred, even after adjusting for age, sex, and comorbidities. 15. Hunt LP, Ben-Shlomo Y, Clark EM, et al; National Joint Registry for England, Wales and Northern Ireland: 90-day mortality after 409,096 total hip replacements for osteoarthritis, from the National Joint Registry for England and Wales: A retrospective analysis. Lancet 2013;382(9898):1097-1104. Medline  DOI The authors looked at NJR data for knee arthroplasty for osteoarthritis. Patient identifiers were used to link these data to the national mortality database and the Hospital Episode Statistics database. Compared with TKA, unicompartmental knee replacement had a substantially lower mortality (hazard ratio [HR] = 0.32; 95% confidence interval [CI] = 0.19 to 0.54; P 130°. Posterior femoral translation and internal tibial rotation increased steadily beyond 90° flexion, and a sharp increase in varus rotation was noted at maximum flexion. Level of evidence: III. 27. Walker PS, Lowry MT, Kumar A: The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine. Clin Orthop Relat Res 2014;472:238-247. Medline  DOI This study analyzed four different posterior-stabilized designs under machine load and showed major differences in motion characteristics among themselves and with motion data from anatomic knees determined in a previous study. Level of evidence: III. 28. Okamoto S, Mizu-uchi H, Okazaki K, Hamai S, Nakahara H, Iwamoto Y: Effect of tibial posterior slope on knee kinematics, quadriceps force, and patellofemoral contact force after posterior-stabilized total knee arthroplasty. J Arthroplasty 2015;30:1439-1443. Medline  DOI In posterior-stabilized TKAs, the maximum quadriceps force and patellofemoral contact force decreased with increasing posterior slope. Anterior sliding of the tibial component and anterior impingement of the anterior aspect of the tibial post were observed at slopes of 5° and 10°, respectively. Level of evidence: III. 29. Colwell CW Jr, Chen PC, D’Lima D: Extensor malalignment arising from femoral component malrotation in knee arthroplasty: Effect of rotating-bearing. Clin Biomech (Bristol, Avon) 2011;26:52-57. Medline  DOI Cadaver knees were tested with fixed-bearing and rotating-­ platform mobile-bearing TKAs. The rotating platform TKAs had less tibiofemoral rotation and patellofemoral lateral shift. Level of evidence: III. 30. Komistek RD, Murphy JA, O’Dell TL: Clinical and kinematic outcomes of a rotating platform posterior stabilized total knee system. J Arthroplasty 2013;28:624-630. Medline  DOI

A bicruciate-retaining TKA was designed and compared with cruciate-retaining TKA and the native knee. 31. Anterior-­posterior laxity with the cruciate-retaining TKA was greater than with the native knee and bicruciate-­ retaining TKA, but no difference was found between the bicruciate-retaining TKA and the native knee. Level of evidence: II. 26. Moynihan AL, Varadarajan KM, Hanson GR, et al: In vivo knee kinematics during high flexion after a posterior-­substituting total knee arthroplasty. Int Orthop 2010;34:497-503. Medline  DOI

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Ten patients with rotating-platform posterior-stabilized TKA achieved an average posterior femoral rollback of the lateral condyle of −5.4 mm, and the average tibiofemoral axial rotation from full extension to maximum weight-bearing flexion was 3.9°. Level of evidence: III. Okamoto N, Nakamura E, Nishioka H, Karasugi T, Okada T, Mizuta H: In vivo kinematic comparison between mobile-bearing and fixed-bearing total knee arthroplasty during step-up activity. J Arthroplasty 2014;29:23932396. Medline  DOI Knee kinematics were fluoroscopically evaluated during step-up activity 1 year after surgery in 20 mobile-bearing TKAs and 20 fixed-bearing TKAs. The total extent of rotation and kinematic differences were minor between the two TKAs. Level of evidence: II.

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Chapter 7: Biomechanics of the Knee

32. Alnahdi AH, Zeni JA, Snyder-Mackler L: Gait after unilateral total knee arthroplasty: Frontal plane analysis. J Orthop Res 2011;29:647-652. Medline  DOI This study evaluated frontal plane kinematics and kinetics in control subjects and during walking 6 months after TKA, and 1 year after unilateral TKA. The nonsurgical knee loading was not different from that of controls except for shorter step length. Level of evidence: III. 33. Levinger P, Menz HB, Morrow AD, Feller JA, Bartlett JR, Bergman NR: Lower limb biomechanics in individuals with knee osteoarthritis before and after total knee arthroplasty surgery. J Arthroplasty 2013;28:994-999. Medline  DOI This study evaluated lower-limb joint kinematics and kinetics in control subjects and before and 12 months after TKA. No significant changes in knee joint kinematics and kinetics were noted despite significant improvements in pain and function. Level of evidence: III. 34. Hatfield GL, Hubley-Kozey CL, Astephen Wilson JL, Dunbar MJ: The effect of total knee arthroplasty on knee joint kinematics and kinetics during gait. J Arthroplasty 2011;26:309-318. Medline  DOI Three-demensional kinematic and kinetic gait patterns of 42 patients with severe knee osteoarthritis were collected 1 week before and 1 year after TKA. Most changes moved toward an asymptomatic pattern and would be considered improvements in motion, function, and loading. Level of evidence: II.

In 32 TKA patients, analysis indicated that peak knee flexion during early stance, peak knee extension, and peak knee extension moment at 4 months postoperative were independent predictors of the gait pattern at 12 months. Level of evidence: II. 36. McClelland JA, Webster KE, Feller JA, Menz HB: Knee kinematics during walking at different speeds in people who have undergone total knee replacement. Knee 2011;18:151155. Medline  DOI

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37. Hubley-Kozey CL, Hatfield GL, Astephen Wilson JL, Dunbar MJ: Alterations in neuromuscular patterns between pre and one-year post-total knee arthroplasty. Clin Biomech (Bristol, Avon) 2010;25:995-1002. Medline  DOI Patients were analyzed during walking 1 week before and 1 year after TKA. There were significantly lower overall activation amplitudes for the quadriceps and hamstrings, with decreased activity during midlate stance after surgery. Significant increases in gastrocnemius activity were found in late stance. Level of evidence: III. 38. Zeni JA Jr, Snyder-Mackler L: Preoperative predictors of persistent impairments during stair ascent and descent after total knee arthroplasty. J Bone Joint Surg Am 2010;92:1130-1136. Medline  DOI In 105 patients, at 2 years following TKA, the preoperative ability to ascend and descend stairs without a handrail was the best predictor of who would not require a handrail after surgery. Level of evidence: I. 39. Huddleston JI, Scarborough DM, Goldvasser D, Freiberg AA, Malchau H: 2009 Marshall Urist Young Investigator Award: How often do patients with high-flex total knee arthroplasty use high flexion? Clin Orthop Relat Res 2009;467:1898-1906. Medline  DOI This study analyzed the prevalence of knee flexion greater than 90° in patients who received high-flexion TKAs, at a minimum 2-years follow-up. The 21 knees flexed more than 90° for an average of 10 ± 3.8 minutes (0.5%). Level of evidence: IV.

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35. Levinger P, Menz HB, Morrow AD, et al: Knee biomechanics early after knee replacement surgery predict abnormal gait patterns 12 months postoperatively. J Orthop Res 2012;30:371-376. Medline  DOI

Patients were assessed walking at comfortable and fast gait speeds 1 year after TKA. Compared with control subjects, the TKA group walked with significantly reduced cadence, reduced stride length, less knee flexion during stance and swing phases, and less knee extension during stance phase. Level of evidence: III.

40. Lee TQ: Biomechanics of hyperflexion and kneeling before and after total knee arthroplasty. Clin Orthop Surg 2014;6(2):117-126. Medline  DOI In cadaver studies after cruciate-retaining and posterior-­ stabilized TKAs, the cruciate-retaining group had significantly larger contact areas, but no significant differences in pressures were noted between the two TKA designs. Level of evidence: III.

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Chapter 8

Minimally Invasive Surgical Approaches to Knee Arthroplasty Giles R. Scuderi, MD  Henry D. Clarke, MD  Christopher A. Dodd, FRCS

Abstract

Keywords: total knee arthroplasty; unicondylar knee arthroplasty; minimally invasive surgery; surgical exposures

The goals in knee arthroplasty are to relieve pain and restore function in a joint that has been compromised by mechanical wear, trauma, or other etiologies. To accomplish these goals, accurate bony preparation and implantation of the prosthetic components is necessary with restoration of soft-tissue balance to the periarticular stabilizers. Historically, this has been accomplished through an extensile exposure using an anterior skin incision combined with a medial parapatellar arthrotomy. In the early 2000s, a resurgence of unicondylar knee arthroplasty (UKA) performed through smaller skin and capsular incisions stimulated interest in performing total knee arthroplasty (TKA) using similar minimally invasive concepts to improve recovery time and pain after surgery. Consequently, TKA performed through shorter skin incisions using various alternative arthrotomy incisions that were perceived to be less damaging to the quadriceps muscle and extensor mechanism were investigated and adopted. These so-called minimally invasive techniques broadly adhere to some or all of the following principles: a smaller skin incision, no eversion of the patella; avoidance of disruption of the suprapatellar pouch; and minimal or no incision of the quadriceps tendon.1 After using these

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Knee arthroplasty can be performed using a variety of skin and arthrotomy incisions. Improving the early recovery of patients undergoing knee arthroplasty by using shorter skin incisions and reducing damage to the quadriceps muscle with minimally invasive surgical techniques was pioneered in unicondylar knee arthroplasty and then continued with total knee arthroplasty. Important work has been undertaken over the past decade to identify the optimal method for exposure in total knee arthroplasty. However, questions remain. Understanding the individual techniques is important for the surgeon performing knee arthroplasty. The decision to use any particular approach should be made by the surgeon performing the procedure after considering patient variables, the prosthesis system to be used, and their individual experience with the exposure options.

Introduction

Dr. Scuderi or an immediate family member has received royalties from Zimmer Biomet; is a member of a speakers’ bureau; or has made paid presentations on behalf of ConvaTec, Medtronic, Pacira, and Zimmer Biomet; serves as a paid consultant to Medtronic, Merz Pharmaceuticals, Pacira, and Zimmer Biomet; has received research or institutional support from Pacira; and serves as a board member, owner, officer, or committee member of Operation Walk USA. Dr. Clarke or an immediate family member has received royalties from ConforMIS; serves as a paid consultant to ConforMIS and Smith and Nephew; serves as an unpaid consultant to ConforMIS; has received research or institutional support from Stryker and Vidacare; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the Association of Bone and Joint Surgeons, and the International Congress for Joint Reconstruction. Dr. Dodd or an immediate family member has received royalties from Zimmer Biomet; is a member of a speakers’ bureau or has made paid presentations on behalf of Zimmer Biomet; serves as a paid consultant to or is an employee of Zimmer Biomet; has received research or institutional support from Stryker, Biomet, and Zimmer; and serves as a board member, owner, officer, or committee member of the Knee Society.

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alternative exposures for more than a decade, no single technique has demonstrated unequivocal superiority. Instead, several alternatives appear to be reasonable choices with relative risks and benefits afforded by each exposure. Indeed, the most appropriate exposure choice in a particular case may depend on patient characteristics, prosthesis and instrumentation variables, and the individual experience and skill of the surgeon performing the procedure. It is important to review the surgical techniques for each of the most widely used exposures for UKA and TKA, along with the relative advantages and disadvantages of each technique.

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Minimally Invasive UKA

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UKA and TKA were both developed in the early 1970s, and surgical exposure was critical. Initially, both procedures were performed via a long medial parapatellar incision, with the patella everted laterally to aid exposure. In 1992, UKAs were implanted via a shorter incision, and it was shown that patellar eversion was unnecessary and that relative preservation of the extensor mechanism resulted in accelerated recovery and early discharge.2 These early presentations stimulated great interest in minimally invasive surgery (MIS), not only for UKA, but also later resulted in the development of MIS TKA. In 1998, the phase 3 mobile UKA development introduced the technique for medial unicompartmental arthroplasty used with a MIS. The instruments were miniaturized for use via a small parapatellar arthrotomy. The functional results and the speed of recovery of phase 3 were found to be better than those of phase 2 mobile-bearing UKA. Since then, most surgeons now implant UKA using an MIS approach. This procedure is ideal for the reduced-incision surgical approach.

synovial cavity. The anterior cruciate ligament (ACL), lateral side, and patellofemoral joint can now be inspected. If the ACL appears damaged, its integrity should be checked by pulling on the ligament with a tendon hook. Absence of a functioning ACL is a contraindication for a mobile-bearing UKA.

Medial Approach For the medial approach, a paramedial skin incision is made from the medial pole of the patella to a point 3 cm distal to the joint line just medial to the tibial tubercle: two-thirds above the joint line to one-third below (Figure 1). The medial margin of the patella is identified. The retinacular incision is made along the medial side of the patella and patellar tendon. The anterior tibia is exposed. At its upper end, the retinacular incision is extended proximally for 2 to 3 cm into the vastus medialis obliquus (VMO) muscle. The direction is not critical, but most surgeons carry the incision proximally up toward the quadriceps tendon. Part of the retropatellar fat pad is excised and the anterior portion of the medial meniscus is removed. Self-retaining retractors are inserted into the

Lateral Approach For a lateral approach, the incision is made over the junction of the central and lateral thirds of the patella and begins at the level of the superior pole of the patella and extends down and just lateral to the tibial tubercle. The retinacular incision is made on the lateral side of the patella and down beside the patellar tendon. The anterolateral portion of the tibia is exposed and the Gerdy tubercle and attachment of the iliotibial tract are identified. The incision is extended proximally around the patella and up into the extensor mechanism. Generous excision of the fat pad is required. If concern exists regarding the ACL, its status can be assessed by pulling it with a tendon hook. In general, the lateral MIS UKA incision is 2 to 3 cm longer than the medial incision.

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Figure 1

Illustration depicts planned medial skin incision for a medial unicondylar arthroplasty.

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Chapter 8: Minimally Invasive Surgical Approaches to Knee Arthroplasty

Clinical Results In comparison with MIS TKA, few studies compare the effect of reduced incisions. Clearly, fewer UKAs are performed (10% of registered knee arthroplasties are UKAs), and surgical approaches are not as varied as in MIS TKA. In essence, the aforementioned medial approach has attained near-universal use.3 The only direct comparison describes the effect of the medial MIS approach.4 This study compared the rate of recovery in 40 mobile-bearing UKAs performed via an MIS incision with modified instruments without patellar eversion with the rate in 20 mobile-bearing UKAs performed via an open approach with patellar eversion. Both groups were compared with 40 TKAs performed during the same period, which were used as controls. The average rate of recovery after the MIS approach was twice as fast as that of open UKA and three times as fast as that of TKA. The authors of this chapter know of no study that assesses the effect of the lateral MIS UKA approach.5 Total Knee Arthroplasty The surgical approach for TKA has evolved over the past decade to less invasive exposures following the experience gained from MIS UKA. Several approaches have become popular, including the limited medial parapatellar approach, the subvastus approach, the midvastus approach, and the quadriceps-sparing approach.

© 2017 American Academy of Orthopaedic Surgeons

Images of a limited medial parapatellar arthrotomy. A, Illustration depicts planned arthrotomy. B, Intraoperative photograph demonstrates exposure.

usually facilitates lateral subluxation of the patella and exposure to the joint. If necessary, the arthrotomy can be easily extended to a more traditional approach by gradual lengthening into the quadriceps tendon. This approach is commonly used because of its familiarity, simplicity, and exposure of all knee joint compartments. Furthermore, this approach is extensile when needed, can be applied to all deformities, and is easily extended with a quadriceps snip when necessary.9 The Subvastus Approach Originally, the subvastus approach was commonly used in TKA to preserve the attachment of the VMO muscle on the quadriceps tendon and follow the natural plane of dissection.10 In the original description, this technique was performed through a standard-length anterior skin incision and the patella was typically everted. However, subsequent modifications allowed the exposure to be performed through a limited skin incision of 3 to 4 inches when preferred.1 Following exposure of the extensor mechanism via a midline skin incision and development of limited medial and lateral subcutaneous flaps, an incision is made along the medial border of the patellar tendon and medial border of the patella to the attachment of the VMO tendon on the patella (Figure 3). The insertion of the VMO occurs at an angle of approximately 50° at approximately the midportion of the patella.11 However, this insertion point varies among individuals, with three broad types described: type 1 has a high insertion of the VMO above the medial aspect of the patella, type 2 inserts at the superior medial border of the patella, and type 3 inserts as low as the middle of the patella and is usually seen in muscular male patients.12 Other reports have described an even more distal insertion of the VMO tendon on the

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The Medial Parapatellar Approach The earliest description of the medial parapatellar approach has been credited to von Langenbeck, who described detachment of the VMO muscle from its insertion onto the quadriceps tendon and continuing the arthrotomy around the medial border of the patella and along the medial border of the patellar tendon.6 This approach was modified by Insall with a straight incision along the medial border of the quadriceps tendon, over the medial border of the patella with a subperiosteal elevation of the medial retinaculum, and a straight incision along the medial border of the patellar tendon.7 The limited medial patellar arthrotomy evolved from the Insall technique. Following a midline skin incision from the superior pole of the patella to the tibial tubercle, limited medial and lateral subcutaneous flaps are developed. The arthrotomy begins approximately 2 to 4 cm proximal to the superior pole of the patella and extends distally along the medial border of the quadriceps tendon.8 The incision is continued in a straight manner and the medial retinaculum is elevated from the medial border of the patella and along the medial border of the patellar tendon (Figure 2). This

Figure 2

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Figure 3

Illustration depicts the subvastus approach. Figure 4

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patella. In one study, approximately 25% of patients had an insertion that occurred distally in excess of 60% of the patellar length.13 With this exposure, the insertion of the VMO remains attached to the patella, and the dissection proceeds transversely along the lower border of the VMO muscle belly. This procedure can often be performed with blunt finger dissection beneath the inferior border of the VMO and along the intermuscular septum. Care should be taken as the dissection extends above the adductor tubercle approaching the Hunter canal. This area has neurovascular structures at risk, including the descending geniculate artery and its branches, the intermuscular septal arteries, and the saphenous nerve. Following dissection of the VMO, the synovial fold in the suprapatellar pouch is released and the patella is subluxated laterally as the knee is moved into flexion. During closure, the horizontal portion of the arthrotomy along the inferior border of the VMO may be closed with the knee at 90° to prevent overtightening of the medial structures that could cause iatrogenic patella baja.1 Proponents of the subvastus approach report exposure comparable with the medial parapatellar arthrotomy, with preservation of the extensor mechanism and minimization of patella instability. The major criticisms of the subvastus approach are poor exposure and difficulty with patellar mobilization. The contraindications for the subvastus

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Illustration depicts the midvastus approach.

approach include obesity, especially with a short femur; heavy, muscular thighs; hypertrophic osteoarthritis with limited range of motion or substantial flexion contracture; prior high tibial osteotomy with patella infera; knees with excessive valgus; and revision TKA. In addition, when combined with a small skin incision, increased trauma to the skin can occur, especially with the stretching required to perform the proximal, medially directed portion of the arthrotomy; this can result in an increased risk of wound healing problems. The Midvastus Approach The midvastus approach was described as a compromise between the medial parapatellar and subvastus approaches.14 Following exposure of the extensor mechanism via a midline skin incision and development of limited medial and lateral subcutaneous flaps, an incision is made along the medial border of the patellar tendon and the medial border of the patella to the attachment of the VMO on the superomedial border of the patella. With the knee in flexion to maintain tension in the extensor mechanism, the full thickness of the VMO is divided in line with its muscle fibers, starting at the superomedial border of the patella and extending proximally approximately

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Chapter 8: Minimally Invasive Surgical Approaches to Knee Arthroplasty

3 cm (Figure 4). The patella is subluxated laterally to expose the knee joint. Inadvertent fascia or muscle fiber tears while exposing the joint have no adverse effects on the outcome. Proponents of the midvastus approach report less postoperative pain, preservation of the patella vascularity, improved patellar tracking, better quadriceps strength, decreased blood loss, and more rapid recovery. Relative contraindications to this approach include obesity, hypertrophic osteoarthritis with limited range of motion or substantial flexion contracture, heavy muscular thigh, patella baja, and revision TKA.

Lateral Approach The lateral approach to the knee was introduced in North America for use in patients undergoing TKA who had a preoperative valgus deformity.17 When this approach was first described, a standard-length laterally based anterior incision was used, but the exposure has been subsequently modified for use with a small, minimally invasive skin incision.18 The original technique follows the skin incision, and medial dissection is contraindicated.17 A lateral arthrotomy is performed beginning proximally along the

© 2017 American Academy of Orthopaedic Surgeons

Figure 5

Illustration depicts the quadriceps-sparing approach.

lateral border of the quadriceps tendon and continued distally 1 to 2 cm lateral to the border of the patella, through the medial edge of the Gerdy tubercle, and extended into the lateral compartment fascia 1 to 2 cm lateral to the edge of the tibial tubercle (Figure 6). During exposure, incision through the fat pad should be avoided because mobilization of the vascularized fat pad is used at the end of the case to close the gap that will form in the lateral capsule as a result of valgus deformity correction. Instead, the fat pad is preserved with the intermeniscal ligament and the anterior rim of the lateral meniscus by dissecting medially, deep to the patellar tendon. This soft-tissue mass is preserved as a laterally based flap with preserved blood supply from the inferior geniculate artery and should be protected during the subsequent surgery. The patella is subluxated medially during arthroplasty. At the time of closure, the vascularized, laterally attached fat pad with the meniscal remnant is mobilized. The fat pad is expanded with relaxing incisions made in line with the retained lateral meniscal rim. This soft-tissue mass is sutured to the lateral edge of the capsule that runs along the border of the extensor mechanism to close the capsular defect. Proponents of the lateral approach note that valgus deformity correction is optimized with this exposure

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Quadriceps-Sparing Approach The quadriceps-sparing approach for TKA was described based on experience with minimally invasive UKA.15 The goal of this approach is to perform a TKA through a less invasive approach that permits more rapid recovery with less morbidity. A curvilinear medial skin incision is made from the superior pole of the patella to the tibial joint line. The medial arthrotomy is in line with the skin incision and begins at the superior medial border of the patella at the insertion of the VMO. It ends approximately 2 cm distal to the tibial joint line just medial to the insertion of the patellar tendon at the tibial tubercle. The arthrotomy does not cut the quadriceps tendon or divide the fibers of the VMO (Figure 5). As noted in the discussion of the subvastus exposure, some variation exists in the insertion of the VMO along the medial border of the patella. For type 3, in which the insertion is at the midportion of patella or more distal, it can be argued that this surgical approach releases the VMO and is not truly quadriceps sparing. When performing TKA using the quadriceps-sparing approach, specialized instruments are necessary that allow resection of the femur and tibia from the medial side of the knee joint. Complications following the quadriceps-­ sparing approach, including patellar tendon avulsion, rupture of the medial or lateral collateral ligaments, and cement retention, appear to decline with increased surgeon experience.16

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been identified.24-29 Certainly, no definitive statements can be made that MIS approaches are superior in all ways to traditional exposures, nor does it appear that any single approach is superior to the others. Meta-analyses and systematic reviews have been performed on this topic over the past 5 years. However, the results of these studies also are equivocal with those that fail to identify any clinical advantages or problems30,31 versus those that note small differences in early recovery or complications.32,33 A broad summary of the published literature suggests that small, early advantages in quadriceps strength, range of motion, and pain relief during the first few weeks after surgery may be possible with minimally invasive approaches versus traditional exposures. However, these benefits appear to be realized at the expense of a small but important increase in wound healing complications, increased surgical time, and potential concerns about long-term loosening resulting from less accurate prosthesis alignment.30-33 Summary

Figure 6

Illustration depicts the lateral arthrotomy.

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because the tight lateral structures are either released during the exposure or directly accessible for release after the lateral exposure has been performed.17 The disadvantages of the technique include the relative lack of familiarity most surgeons have with a lateral perspective during TKA; instruments for TKA that are mostly designed for a medial approach; and problems with poor capsular closure, especially if the fat pad flap is damaged, which can contribute to postoperative drainage and infection or slow rehabilitation.17,18 Clinical Results The clinical outcomes of TKA performed with different exposures have been compared in many trials to determine whether MIS exposures are superior to traditional approaches, and also to determine which MIS exposure is optimal. Even with the peer-reviewed publications from the past decade, limited conclusions can be drawn from the literature. Information from early reports that compared MIS techniques to traditional exposures demonstrated advantages; however, most of these were case-control studies using historic or contemporary control patients instead of randomized subjects.19-23 In more recent randomized studies, no significant clinical advantages have

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The goal of knee arthroplasty is to restore function and eliminate pain in a knee joint that is compromised by mechanical damage or disease. Optimal surgical exposure is required to allow accurate preparation of the bones for implant placement and to perform soft-tissue balancing. Although most knee arthroplasties have been historically performed through a skin incision 20 cm or longer and a medial parapatellar arthrotomy, alternative surgical exposures using shorter incisions and more limited arthrotomies have been investigated to determine if less theoretical damage to the quadriceps muscle and periarticular soft tissue would result in better outcomes. In the setting of UKA, MIS approaches have become the standard exposure for the procedure. After studying the use of alternative techniques for more than a decade, including mini-medial parapatellar arthrotomy, modified subvastus, midvastus, and quadriceps-sparing approaches, no conclusive evidence has demonstrated the superiority of any one technique in TKA. Although small, short-term advantages have been demonstrated by some authors with some techniques, the available literature instead suggests that each technique has relative minor advantages and disadvantages. Indeed, patient, instrumentation, prosthesis, and surgeon factors likely influence the most suitable exposure in any given case. Based on the available data, each surgical approach is reasonable for use with TKA. The specific exposure selected in each case should be made by the operating surgeon based on an evaluation of patient factors, the prosthetic system used, and his or her experience.

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Key Study Points

Annotated References 1. Pagnano MW, Meneghini RM: Minimally invasive total knee arthroplasty with an optimized subvastus approach. J Arthroplasty 2006;21(4suppl 1):22-26. Medline  DOI 2. Repicci JA, Eberle RW: Minimally invasive surgical technique for unicondylar knee arthroplasty. J South Orthop Assoc 1999;8(1):20-27, discussion 27. Medline 3. Pandit H, Jenkins C, Barker K, Dodd CA, Murray DW: The Oxford medial unicompartmental knee replacement using a minimally-invasive approach. J Bone Joint Surg Br 2006;88(1):54-60. Medline  DOI 4. Price AJ, Webb J, Topf H, Dodd CA, Goodfellow JW, Murray DW; Oxford Hip and Knee Group: Rapid recovery after oxford unicompartmental arthroplasty through a short incision. J Arthroplasty 2001;16(8):970-976. Medline  DOI

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This study reported on a prospective, independent evaluation of 265 consecutive knees with isolated lateral compartmental disease. The survival rate at 8 years was 92.1% with 12 reoperations, 4 of which were for bearing dislocation (1.5%). The MIS lateral approach was considered to be one of the factors that helped decrease the dislocation rate. 6. von Langenbeck B: Zur resection des kniegelenke. Verh Dtsch En Geseuch F Chir 1879;7:23. 7. Insall J: A midline approach to the knee. J Bone Joint Surg Am 1971;53(8):1584-1586. Medline 8. Scuderi GR, Tenholder M, Capeci C: Surgical approaches in mini-incision total knee arthroplasty. Clin Orthop Relat Res 2004;428:61-67. Medline  DOI 9. Garvin KL, Scuderi G, Insall JN: Evolution of the quadriceps snip. Clin Orthop Relat Res 1995;321:131-137. Medline 10. Hofmann AA, Plaster RL, Murdock LE: Subvastus (Southern) approach for primary total knee arthroplasty. Clin Orthop Relat Res 1991;269:70-77. Medline 11. Pagnano MW, Meneghini RM, Trousdale RT: Anatomy of the extensor mechanism in reference to quadriceps-sparing TKA. Clin Orthop Relat Res 2006;452(452):102-105. Medline  DOI 2: Knee

• Exposure for knee arthroplasty was traditionally achieved with an anterior skin incision and a medial parapatellar arthrotomy. • Less invasive exposures using short skin incisions and capsular arthrotomies were first used in UKA to reduce pain and speed rehabilitation, and have become widely accepted. • Similar concepts to improve early recovery generated significant interest in the 2000s in so-called minimally invasive TKA using a variety of exposures performed through short skin incisions that theoretically caused less damage to the quadriceps muscle and extensor mechanism. These exposures included the mini-parapatellar, modified subvastus, mini-midvastus, and quadriceps-sparing approaches to the knee. • After more than a decade of use in TKA, the published randomized prospective studies comparing both MIS techniques with a standard medial parapatellar arthrotomy, and different minimally invasive techniques to each other, have failed to identify a single approach that is clearly optimal. • TKA can be successfully performed using a variety of surgical exposures that have relative advantages and disadvantages. The optimal technique in any case likely depends on several variables, including patient characteristics, implant and instrumentation design, and surgeon experience.

5. Weston-Simons JS, Pandit H, Kendrick BJ, et al: The mid-term outcomes of the Oxford Domed Lateral unicompartmental knee replacement. Bone Joint J 2014; 96-B(1):59-64. Medline  DOI

12. Tria AJ Jr: Minimally invasive total knee arthroplasty using quadriceps-sparing approach, in Scuderi GR, Tria AJ Jr, Berger RA, eds: MIS Techniques in Orthopaedics. New York, Springer, 2005, p 349. 13. Holt G, Nunn T, Allen RA, Forrester AW, Gregori A: Variation of the vastus medialis obliquus insertion and its relevance to minimally invasive total knee arthroplasty. J Arthroplasty 2008;23(4):600-604. Medline  DOI 14. Engh GA, Holt BT, Parks NL: A midvastus muscle-splitting approach for total knee arthroplasty. J Arthroplasty 1997;12(3):322-331. Medline  DOI 15. Tria AJ Jr, Coon TM: Minimal incision total knee arthroplasty: Early experience. Clin Orthop Relat Res 2003;416:185-190. Medline  DOI 16. Jackson G, Waldman BJ, Schaftel EA: Complications following quadriceps-sparing total knee arthroplasty. Orthopedics 2008;31(6):547. Medline  DOI 17. Keblish PA: The lateral approach to the valgus knee. Surgical technique and analysis of 53 cases with over two-year follow-up evaluation. Clin Orthop Relat Res 1991;271:52-62. Medline

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18. Seyler TM, Bonutti PM, Ulrich SD, Fatscher T, Marker DR, Mont MA: Minimally invasive lateral approach to total knee arthroplasty. J Arthroplasty 2007;22(7suppl 3): 21-26. Medline  DOI 19. Chen AF, Alan RK, Redziniak DE, Tria AJ Jr: Quadriceps sparing total knee replacement. The initial experience with results at two to four years. J Bone Joint Surg Br 2006;88(11):1448-1453. Medline  DOI 20. Dutton AQ, Yeo SJ, Yang KY, Lo NN, Chia KU, Chong HC: Computer-assisted minimally invasive total knee arthroplasty compared with standard total knee arthroplasty. A prospective, randomized study. J Bone Joint Surg Am 2008;90(1):2-9. Medline  DOI 21. Haas SB, Cook S, Beksac B: Minimally invasive total knee replacement through a mini midvastus approach: A comparative study. Clin Orthop Relat Res 2004;428: 68-73. Medline  DOI 22. McAllister CM, Stepanian JD: The impact of minimally invasive surgical techniques on early range of motion after primary total knee arthroplasty. J Arthroplasty 2008;23(1):10-18. Medline  DOI 23. Tashiro Y, Miura H, Matsuda S, Okazaki K, Iwamoto Y: Minimally invasive versus standard approach in total knee arthroplasty. Clin Orthop Relat Res 2007;463(463): 144-150. Medline 24. Aglietti P, Baldini A, Sensi L: Quadriceps-sparing versus mini-subvastus approach in total knee arthroplasty. Clin Orthop Relat Res 2006;452(452):106-111. Medline  DOI 2: Knee

25. Bonutti PM, Zywiel MG, Ulrich SD, Stroh DA, Seyler TM, Mont MA: A comparison of subvastus and midvastus approaches in minimally invasive total knee arthroplasty. J Bone Joint Surg Am 2010;92(3):575-582. Medline  DOI This prospective, randomized study reported on 51 patients who underwent bilateral TKA using short skin incisions with a subvastus exposure on one side and a midvastus exposure on the other. Early clinical outcomes at 2-year follow-up did not identify any significant differences between the exposures. Level of evidence: I. 26. Bourke MG, Jull GA, Buttrum PJ, Fitzpatrick PL, Dalton PA, Russell TG: Comparing outcomes of medial parapatellar and subvastus approaches in total knee arthroplasty: A randomized controlled trial. J Arthroplasty 2012;27(3):347-353.e1. Medline  DOI This study compared 90 patients who underwent TKA with either a standard medial parapatellar arthrotomy or a subvastus exposure. The only significant differences identified were better Knee Society functional scores at 12 and 18 months and less surgeon-perceived difficulty performing the surgery in the medial parapatellar group versus fewer days postoperatively to perform the straight leg raise in the subvastus group. The authors concluded that no clinically significant benefits to using the subvastus exposure exist.

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27. Heekin RD, Fokin AA: Mini-midvastus versus mini-medial parapatellar approach for minimally invasive total knee arthroplasty: Outcomes pendulum is at equilibrium. J Arthroplasty 2014;29(2):339-342. Medline  DOI In this report, 40 patients who underwent staged bilateral TKA were prospectively randomized for a mini-­midvastus exposure on one side and a mini-medial parapatellar approach on the other. Clinical outcomes revealed inconsistent patterns of differences at various intervals. Surgical outcomes were not different. No major differences were reported in outcomes between the two approaches. The authors recommended that surgeons use the surgical approach with which they are most familiar. 28. Kim YH, Kim JS, Kim DY: Clinical outcome and rate of complications after primary total knee replacement performed with quadriceps-sparing or standard arthrotomy. J Bone Joint Surg Br 2007;89(4):467-470. Medline  DOI 29. Nestor BJ, Toulson CE, Backus SI, Lyman SL, Foote KL, Windsor RE: Mini-midvastus vs standard medial parapatellar approach: A prospective, randomized, double-blinded study in patients undergoing bilateral total knee arthroplasty. J Arthroplasty 2010;25(6suppl):5-11. Medline  DOI This study reported on 27 patients who underwent bilateral TKA with a mini-midvastus exposure on one side and a standard medial parapatellar arthrotomy on the other. At 3 weeks, strength in the limb with the mini-midvastus exposure had improved, but no other clinically significant differences were reported. 30. Bourke MG, Buttrum PJ, Fitzpatrick PL, Dalton PA, Jull GA, Russell TG: Systematic review of medial parapatellar and subvastus approaches in total knee arthroplasty. J Arthroplasty 2010;25(5):728-734. Medline  DOI This systematic review compared the outcomes of the medial parapatellar and subvastus surgical approaches for TKA. Only five published studies (from 1993 and 2001) met the inclusion quality standards for the review. The evidence was insufficient to demonstrate a clinical or significant difference across all outcomes. The poor quality of these studies was an important limitation; additional high-quality studies are needed. 31. Smith TO, King JJ, Hing CB: A meta-analysis of randomised controlled trials comparing the clinical and radiological outcomes following minimally invasive to conventional exposure for total knee arthroplasty. Knee 2012;19(1):1-7. Medline  DOI This meta-analysis compared the clinical and radiologic outcomes of minimally invasive and conventional exposure TKAs for 18 studies including 1,582 TKAs (822 minimally invasive versus 760 conventional exposure TKAs). The incision length was significantly smaller, and flexion range of motion was significantly greater following MIS, but no significant differences were reported for all other outcomes between the approaches.

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32. Cheng T, Liu T, Zhang G, Peng X, Zhang X: Does minimally invasive surgery improve short-term recovery in total knee arthroplasty? Clin Orthop Relat Res 2010;468(6):1635-1648. Medline  DOI This article reports on the results of a systematic review and meta-analysis of 13 trials published from 2007 to 2009 that compared minimally invasive knee arthroplasty versus standard TKA. MIS results in faster recovery than conventional surgery, with similar rates of component malalignment but is associated with more frequent instances of delayed wound healing and infections.

33. Gandhi R, Smith H, Lefaivre KA, Davey JR, Mahomed NN: Complications after minimally invasive total knee arthroplasty as compared with traditional incision techniques: A meta-analysis. J Arthroplasty 2011;26(1):29-35. Medline  DOI This meta-analysis compared the incidence of complications between MIS and standard TKA approaches in randomized controlled trials. A higher rate of complications was identified in the MIS group but alignment was no different. The authors noted that knee MIS should be approached with caution.

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Chapter 9

Kinematics in Total Knee Arthroplasty William M. Mihalko, MD, PhD

Abstract Understanding how different total knee implant design variations affect knee kinematics is essential to optimize surgical techniques and outcomes for patients. Different levels of constraint and posterior cruciate retention, sacrifice, or substitution will all affect the resulting kinematic profile of the knee after surgery. It is important to review aspects of different designs and evidence in the literature of how these designs may affect kinematics after surgery.

Keywords: knee; implant; kinematics; constraint

of the design rationales are driven by normal knee kinematic variables as well as the desire to improve patient satisfaction and function after surgery. In reality, design variables in a TKA implant may not result in the motion that was desired by the designers. Many reports in the literature and in vivo studies show kinematic profiles of TKAs that do not follow normal knee kinematic profiles.1-7 Reports of in vivo kinematics most likely rely on multiple variables, including patient anatomy, surgical technique, and even excessive body mass index and joint loads.8-14 Implant design can also be dependent on surgical technique, about which there is active debate (eg, mechanical versus kinematic alignment; gap balancing versus matched resection).15-18

Introduction Condylar total knee arthroplasty (TKA) has seen many implant design changes over the last two decades, but the concept of total condylar arthroplasty remains largely unaltered. Some design changes include an increase in the number of available sizes; others use mobile bearings, others are bicruciate-substituting or -retaining, and yet others incorporate medial pivot-driven constraints. Many Dr. Mihalko or an immediate family member has received royalties from Aesculap/B. Braun; is a member of a speakers’ bureau or has made paid presentations on behalf of Aesculap/B.Braun and CeramTec; serves as a paid consultant to Aesculap/B. Braun, Medtronic, and the Department of Defense; has received research or institutional support from Aesculap/B. Braun, MicroPort, Smith & Nephew, and Stryker; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons, the American Orthopaedic Association, and ASTM International.

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Implant Design and Effects on Kinematics A large degree of variability exists in the kinematics of the replaced knee, and no consensus exists on a definitive design that best re-creates the kinematics of the normal knee. This in part has to do with the fact that arthritis—whether inflammatory, posttraumatic, or osteoarthritis—affects more than just the surface geometry of the joint. Some designs have centered on the effect and importance of the posterior cruciate ligament (PCL). Functionally, the PCL provides most of the total restraining force against posterior translation of the tibia relative to the femur, and it supports stability of the knee and the joint space in flexion.19 In the PCL-retaining knee, the conservation of this ligament is designed to reduce the posterior translation of the tibia and to contribute to femoral rollback in deep knee flexion.20-22 Retention of the PCL theoretically enables rollback of the femur on the tibia with knee flexion, allowing for more efficient use of extensor musculature.23 However, a debate continues in the literature regarding the benefits of retaining the PCL in TKA.24-26 The design of a posterior stabilized TKA requires additional anterior-posterior stability, which is effectively achieved by placement of a femoral cam and tibial post. Proponents of the posterior

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Figure 1

A, Illustration of cam and post interaction. A cam that is positioned at the top and most posterior aspect of the femoral posterior condyles will tend to interact with the tibial post later in the flexion arc, but will tend to remain at the base of the post in the extremes of flexion, thereby maximizing the jump height of the cam on the post. As the cam moves anteriorly across the box (dark circle), the interaction will tend to occur earlier in flexion and will articulate higher on the post late in the flexion arc, thereby decreasing the jump height. B, Lateral radiograph of the knee of a patient after total knee arthroplasty with a posterior stabilized implant who felt a "pop" while working under his vehicle and could not bend his knee. A jumped post in a posterior stabilized design implant is a complication that occurs when the flexion space is greater than the jump height of the post.

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stabilized designs purport that it offers a more reproducible kinematic profile and increased range of motion than the cruciate-­retaining design, whereas opponents argue that increased femoral bone loss and added implant constraint, possibly increasing the risk of aseptic loosening, are pitfalls of the design. Several studies report no difference in functional outcome between posterior-­stabilizing or cruciate-­retaining TKAs.25,27,28 Opponents of posterior stabilized TKA-designed implants also argue that the knee is more stable in flexion without affecting the flexion gap, and important mechanoreceptors in the PCL are retained that can affect function after surgery.29 Post and Cam Positioning in Posterior Stabilized Implant Design The posterior stabilized TKA implants afford stability to the knee by blocking posterior translation of the tibia on the femur through a post (on the polyethylene insert) and a cam (on the posterior femoral condyles or bridging a box between the condyles of the femur). Design changes, for example, the position and shape of the post and cam, affect the guided or constrained motion of the femur on the tibia and have consequences as well on the amount of congruency and subsequent wear on the tibial polyethylene.30 In the initial posterior stabilized designs, the post and cam were symmetric.31 The post was positioned centrally

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within the tibial polyethylene insert, and the cam spanned the posterior femoral condyles. This design engaged the cam on the post at approximately 60° and then drove rollback of the posterior femoral condyles on the tibial polyethylene insert symmetrically until edge loading of the posterior femoral condyles on the polyethylene insert occurred at approximately 120° of flexion. This was the basis of design for all posterior stabilized TKA implants going forward. By examining how the post and cam positioning affect both when and how the interaction of the post and cam occurs, a basic understanding of the design attributes can be inferred. If the post is positioned centrally in the baseplate, it is possible to determine how moving the cam affects the interaction of the two and drives the motion of the femur with respect to the tibia. If the cam is positioned more anteriorly across the sides of the box, then the post will interact with the cam at an earlier point during the flexion arc; once engaged, the contact of the cam will be maintained in the midportion of the post. If the cam is moved to a more posterior position on the femur, or at the top of the femoral condyles, then the cam will contact the post at a later point in the flexion arc, move down the post, and remain at the base of the post, even with extremes of flexion, thereby maximizing the jump height.6,30,32 This keeps the knee stable in flexion and prevents a jumped-post dislocation after surgery (Figure 1). Some implants now incorporate an articulating

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Chapter 9: Kinematics in Total Knee Arthroplasty

Figure 3

Figure 2

Photograph of a knee implant retrieved at necropsy after more than 10 years' implantation shows an example of a rectangular post cross-section with sharp edges and a cam that is located midway along the height of the posterior condyles. This configuration provides contact earlier in the flexion arc and moves contact up the post after around 90° of flexion. The medial and lateral wear scars are symmetric and do not force as much rollback in this configuration with edge impingement, as is seen in the posterior aspect of the polyethylene insert where it impinged on the posterior aspect of the femur in flexion.

© 2017 American Academy of Orthopaedic Surgeons

Asymmetric cam designs have now been introduced in which one side of the cam has a larger diameter. The smaller diameter is typically placed on the medial side, and the varying larger diameter on the lateral side (Figure 4). This design feature is intended to guide a medial pivot. This pivot occurs with increasing flexion from the wider diameter of the cam on the lateral side and pushes the lateral femoral condyle posteriorly to effect rollback, whereas the smaller diameter on the medial side tends to keep the medial femoral condyle centrally located with more sliding motion. Cruciate-Retaining TKA Implant Design Attributes and Kinematics

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area on the anterior aspect of the post on the anterior aspect of the box to guide motion in terminal extension. This type of dual-cam design adds another articulating surface, but may guide motion in terminal extension more consistently. Cam and post geometry in the transverse plane will also change the way the femur and tibia interact. If the post has a rectangular cross-section, then it may constrain rotation of the femur on the tibia in the transverse plane, depending on the overall width of the post. This design feature will cause edge loading of the post on the condylar edges of the femoral component. This can be seen in the retrieved implant shown in Figure 2. This implant shows the square edges of the polyethylene post and a wear scar along the sides from overconstraint in the transverse plane. If the post has a rounded transverse plane geometry with less condylar constraint to internal and external rotation, then less burnishing and edge wear may result30 (Figure 3). Post height and position can also affect flexion and kinematics in other ways. If the post is straight and too tall, with a more anterior position, there is risk of impingement of the top of the post on the inferior aspect of the patellar button (known as post–patellar conflict). When this occurs, the patient typically feels a block to further flexion and pain as the post collides with the patella.

Photographs of a posterior stabilized knee implant retrieved at necropsy after more than 10 years' implantation. A, The post has a more rounded cross-section and the cam is located more toward the base of the posterior femoral condyles. B, The lateral aspect of the post shows an impingement wear scar from the inner aspect of the lateral condyle of the femoral implant as well as an impingement scar at the top of the straight post, where a patellar button post conflict occurred in flexion.

Cruciate-retaining TKA implants have evolved from flaton-flat minimal constraint designs (in the early 1990s) to those that tend to balance the amount of implant constraint to aid in guiding femoral tibial motion. To prevent the medial femoral condyle from sliding forward, many designs incorporate a deep-dish or ultracongruent option for a tibial polyethylene insert. This design feature makes certain the medial femoral condyle does not slide forward, creating an anterior block to the medial femoral condyle on the medial tibial polyethylene. Many designs, however, have shown a tendency for the femoral articulation to slide forward with increasing flexion. A single radius femoral condylar design can aid in keeping the medial femoral condyle from sliding forward.33 Range of motion after posterior cruciate-retaining TKA has been reported to be improved when the posterior condylar offset is reestablished.8,9 If the posterior condyles are overresected, the posterior aspect of the tibia may come in contact with the posterior aspect of the femur and result in suboptimal flexion. Later reports have shown that measuring this variable radiographically is difficult, and a combination of

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Figure 4

Photograph of an asymmetric cam with a larger lateral diameter, used to guide lateral rollback and a medial pivot.

variables (including implant design and tibial slope) may also play a role in the amount of flexion obtained as well as in the function of the PCL after surgery.8,34 Mobile-Bearing Design Rationale and Kinematics

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Potential advantages of mobile-bearing knee implants include lower contact stresses at the articulating surfaces, rotational motion of the tibial polyethylene during gait, and self-alignment of the tibial polyethylene compensating for small rotational malalignment of the tibial baseplate during implantation. Recent studies have found a higher revision rate in both the early and midterm follow-up periods with a mobile-bearing insert compared with a fixed-bearing TKA.35,36 Whether mobile-bearing designs will outperform fixed-bearing designs is yet to be determined, and performance may be specific to individual manufacturer designs. A recent meta-analysis found moderate- to low-quality evidence that cruciate-retaining mobile-bearing TKA was as good as fixed-bearing TKA.37 In Vivo TKA Kinematics Numerous kinematic fluoroscopic studies have been conducted comparing cruciate-retaining with posterior stabilized designed implants.1-5,33 The results of kinematic studies performed in a normal human knee have shown increased posterior motion in the lateral condyle, compared to the medial condyle, throughout flexion, and these studies are typically used to compare the measured kinematics after TKA.38 Although neither posterior stabilized nor cruciate-retaining in vivo fluorokinematic studies completely replicate normal knee kinematics, variations are worth noting. In the sagittal plane, cruciate-retaining designs have shown a forward sliding of the medial femoral condyle during a lunge and or squatting-type of maneuver.39 Posterior stabilized designs have shown more

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consistent motion, but not one that is always comparable to that of the normal knee. Although a lunge-type movement is rarely used in daily activities, it does give a basis of comparison for TKA patients; some studies have analyzed more demanding activities, such as rising from a chair and kneeling.1 Patients with a posterior stabilized implant design tend to have a neutral or anterior position of the femoral component at full extension, with progressive posterior femoral rollback being achieved with increasing knee flexion. Therefore, although the cruciate-retaining design has been used with great clinical success, the kinematics and flexion performance differ from those of a normal knee. In the transverse plane, both posterior stabilized and cruciate-retaining designs have been reported to have significant variations. Both designs have been shown in some studies to have important variations, with 25% or more of patients showing internal tibial rotation with respect to the femur as the knee goes into flexion. This motion has not been completely explained, but it has been suggested that patients who experience it tend to be less satisfied with the surgery. 3 Fluoroscopy has also been used to report cam-post interactions. One study investigated when the cam-post interaction occurred throughout flexion, the location of the cam on the tibial post when contact occurred, and the height of contact of the cam on the tibial post during deep knee bending for three types of implants: bicruciate-stabilized, fixed-bearing posterior stabilized, and rotating-platform posterior stabilized design.2 The study found that the bicruciate-stabilized TKA had lower contact angles, lower cam-post distance throughout flexion, and a higher height of contact on the tibial post compared to both posterior stabilized designs. It also found that the location of contact on the tibial post remained centered in the rotating-platform posterior stabilized design, whereas in fixed-bearing posterior stabilized designs, contact moved from the medial aspect of the tibial post to the center of the tibial post during flexion.2 Another fluorokinematic study looked at how the maximum flexion angle affected two different groups after TKA, one with greater than 15° of normal rotation and one with greater than 3° of reverse rotation in the transverse plane.3 The study found that the group with reverse axial rotation had lower maximum flexion angles than the group with normal rotation. Therefore, axial rotation was found to influence weight-bearing knee flexion. Knees with normal rotation obtained deeper flexion than those with reverse rotation. Therefore, the reverse rotation pattern may limit flexion. This study suggests that patients may be less satisfied with the surgery when this type of motion pattern occurs after TKA surgery.3

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Chapter 9: Kinematics in Total Knee Arthroplasty

Another study that investigated a TKA implant with a dual cam design tested the theory that the design would decrease intersurgeon variability in patient knee kinematics after surgery.4 Three different groups were created from three different surgeons. The overall motion patterns among the groups were similar, but intrasurgeon differences were found in in vivo kinematics. One group had a greater relative axial rotation than the other two groups. This difference shows that this type of implant does not function as a mechanically constrained system and that surgical technique and soft-tissue handling play a role in the outcome of implant function.4 In vivo fluorokinematic studies of mobile-bearing designs have shown that the bearing rotation in the transverse plane may be nonphysiologic in some patients.2,5,9 This internal transverse plane motion has been reported in all types of TKA bearings and does not seem to be specific to any single design. TKA Computational Kinematic Models

© 2017 American Academy of Orthopaedic Surgeons

Summary Constant innovations in design and technique have improved functional results of TKA, but no clear consensus has been reached concerning the superiority of different designs. Implants that sacrifice or retain the posterior cruciate ligament, implants with different positioning and shapes of the post and cam, and mobile- or fixed-bearing designs all have advantages and disadvantages in the restoration of normal knee kinematics. Outcomes also can be affected by surgical technique, about which debate continues (eg, mechanical or kinematic alignment, gap balancing or matched resection), as well as patient-related factors (eg, age, body mass index, preexisting deformity, individual anatomy). Key Study Points • An understanding of normal knee kinematics and individual patient characteristics are essential to choosing the appropriate implant design for each patient. • TKA implant designs have evolved over the past two decades to a number of modifications intended to improve knee kinematics after surgery; however, not all have been successful in improving functional outcomes. • Several recent reports in the literature show no difference in functional outcomes between posterior-­ stabilizing and cruciate-retaining implants. • Whether mobile-bearing designs will outperform fixed-bearing designs is yet to be determined, but recent studies have found a higher revision rate in both the early and midterm follow-up periods with a mobile-bearing insert compared to a fixed-­ bearing TKA. • In addition to restoration of joint kinematics, outcomes can be affected by surgical technique, about which debate continues (eg, mechanical or kinematic alignment, gap balancing or matched resection), as well as patient-related factors (eg, age, body mass index, preexisting deformity, individual anatomy).

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Several TKA kinematic models have been validated using the Oxford knee rig.12,13 This testing frame simulates a squat maneuver under applied muscle control. Both cruciate-retaining and posterior stabilized implants have been modeled with several assumptions and loading/boundary conditions to assess TKA kinematics and study variables that may effectively change kinematics after surgery. One common variable that has been studied is component suboptimal rotation in the transverse plane. Externally rotated femoral components introduced varus alignment in flexion, whereas internally rotated femoral components induced valgus alignment. Anterior-posterior translation for both cruciate-retaining and posterior stabilized implants was more sensitive to tibial than femoral alignment. The medial condyle of the cruciate-retaining implant exhibited anterior translation, whereas the lateral contact point exhibited posterior translation when the tibial component was internally rotated. In the posterior stabilized implant, all combinations of component rotation exhibited posterior translations. In this model, more posterior femoral rollback was seen for the posterior stabilized implant compared to the cruciate-retaining implant, which is consistent with in vivo studies.12 In one study, a three-dimensional computational model was used to show how small rotational variations of the femoral and tibial components in the transverse plane can alter the femorotibial contact patterns.40 These variations may be a contributing factor to reverse rotation of the femur with respect to the tibia, which has been reported in some of the aforementioned fluorokinematic studies.

The literature is abundant in joint kinematic studies that evaluate the physiologic representation of numerous component designs. One kinematic study, using a model designed with a highly congruent medial compartment and less conforming lateral compartment, successfully replicated kinematics of a normal knee and achieved satisfactory clinical outcomes.41

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Annotated References

the valgus knee operated by the gap-balancing technique. Knee 2014;21(6):1124-1128. Medline  DOI

1. Nakamura S, Sharma A, Kobayashi M, et al: 3D in vivo femoro-tibial kinematics of tri-condylar total knee arthroplasty during kneeling activities. Knee 2014;21(1):162-167. Medline  DOI

A fluorokinematic analysis is presented of 16 posterior stabilized TKAs in patients who had preoperative valgus deformity and a gap balancing surgical technique. Similar medial pivot patterns were seen from full extension to mid flexion. Level of evidence: IV.

This study evaluated 54 bisurface TKAs utilizing three-­ dimensional fluoroscopic kinematic analysis with a kneeling maneuver comparing a flat versus dished polyethylene insert. Flat inserts had greater flexion but both had reverse rotation in the transverse plane. 2. Zingde SM, Leszko F, Sharma A, Mahfouz MR, Komistek RD, Dennis DA: In vivo determination of cam-post engagement in fixed and mobile-bearing TKA. Clin Orthop Relat Res 2014;472(1):254-262. Medline  DOI This study analyzed 15 fixed-bearing posterior stabilized TKAs and 9 rotating platform TKAs undergoing a lunge type of deep knee bend. The rotating platform engaged the post medially while the rotating platform contacted the post centrally. 3. Meccia B, Komistek RD, Mahfouz M, Dennis D: Abnormal axial rotations in TKA contribute to reduced weightbearing flexion. Clin Orthop Relat Res 2014;472(1):248-253. Medline  DOI Of 120 patients analyzed with a TKA under in vivo three-dimensional fluoroscopy, 62 patients experienced more than 3° of reverse axial rotation with internal rotation of the femur relative to the tibia.

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4. Victor J, Mueller JK, Komistek RD, Sharma A, Nadaud MC, Bellemans J: In vivo kinematics after a cruciate-­substituting TKA. Clin Orthop Relat Res 2010;468(3):807-814. Medline  DOI Three-dimensional fluoroscopic analysis of 86 bicruciate-­ substituting TKAs found transverse plane rotation through a range of motion was closer to the normal knee pattern but of lower magnitude. Level of evidence: III. 5. Yamazaki T, Futai K, Tomita T, et al: 3D kinematics of mobile-bearing total knee arthroplasty using X-ray fluoroscopy. Int J Comput Assist Radiol Surg 2015;10(4): 487-495. DOI Medline This study introduces a new technique using tantalum beads in the polyethylene insert to more accurately track kinematics in vivo. 6. Lin KJ, Huang CH, Liu YL, et al: Influence of post-cam design of posterior stabilized knee prosthesis on tibiofemoral motion during high knee flexion. Clin Biomech (Bristol, Avon) 2011;26(8):847-852. Medline  DOI

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8. Onodera T, Majima T, Nishiike O, Kasahara Y, Takahashi D: Posterior femoral condylar offset after total knee replacement in the risk of knee flexion contracture. J Arthroplasty 2013;28(7):1112-1116. Medline  DOI This study analyzed 100 radiographs in Japanese subjects and compared anatomic femoral offset to implant posterior condylar femoral offset. Implants on average were 4.7 times the normal offset. 9. Hanratty BM, Thompson NW, Wilson RK, Beverland DE: The influence of posterior condylar offset on knee flexion after total knee replacement using a cruciate-­ sacrificing mobile-bearing implant. J Bone Joint Surg Br 2007;89(7):915-918. Medline  DOI 10. Andrawis J, Akhavan S, Chan V, Lehil M, Pong D, Bozic KJ: Higher preoperative patient activation associated with better patient-reported outcomes after total joint arthroplasty. Clin Orthop Relat Res 2015;473(8):2688-2697. Medline  DOI One hundred thirty-five patients undergoing total hip arthroplasty and TKA were enrolled in this study, and patient activation measures and patient-reported outcomes were evaluated. Higher patient activation measures led to better pain relief and greater satisfaction. Level of evidence: II. 11. Harman MK, Banks SA, Kirschner S, Lützner J: Prosthesis alignment affects axial rotation motion after total knee replacement: A prospective in vivo study combining computed tomography and fluoroscopic evaluations. BMC Musculoskelet Disord 2012;13:206. Medline  DOI Eighty patients with a mobile-bearing, cruciate-retaining TKA underwent CT to analyze axial rotation. The study concluded that if 5° or less of transverse plane mismatch could be maintained, then flexion may be optimized. 12. Thompson JA, Hast MW, Granger JF, Piazza SJ, Siston RA: Biomechanical effects of total knee arthroplasty component malrotation: A computational simulation. J Orthop Res 2011;29(7):969-975. Medline  DOI Using a forward dynamic computer model, this study found that femoral rotation had a greater effect on soft-­ tissue sleeve tension and quadriceps force, whereas tibial component transverse rotation affects anteroposterior translation.

Using a dynamic knee model, this study reported differences in knee kinematics using a flat-on-flat high flex versus a curved designed polyethylene insert. The model showed that medial post contact constrained transverse rotation and lower constraint in the transverse plane should be considered for better range of motion.

13. Mihalko WM, Conner DJ, Benner R, Williams JL: How does TKA kinematics vary with transverse plane alignment changes in a contemporary implant? Clin Orthop Relat Res 2012;470(1):186-192. Medline  DOI

7. Suzuki K, Hara N, Mikami S, et al: In vivo kinematic analysis of posterior-stabilized total knee arthroplasty for

Using a computer model, this study found that tibial component internal rotation resulted in the largest anteroposterior translational measures and that the transverse

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Chapter 9: Kinematics in Total Knee Arthroplasty

plane femoral-to-tibial component mismatch can explain variations seen during fluorokinematic studies. 14. Huffman KD, Sanford BA, Zucker-Levin AR, Williams JL, Mihalko WM: Increased hip abduction in high body mass index subjects during sit-to-stand. Gait Posture 2015;41(2):640-645. Medline  DOI This study compared 9 patients with high body mass index to 10 normal control patients during sit-to-stand tasks in a gait analysis laboratory. The high body mass index group had 50% greater abduction throughout the entire sit-to-stand cycle. 15. Howell SM, Papadopoulos S, Kuznik K, Ghaly LR, Hull ML: Does varus alignment adversely affect implant survival and function six years after kinematically aligned total knee arthroplasty? Int Orthop 2015;39(11):2117-2124. Medline  DOI This study prospectively followed 219 kinematically aligned TKAs and found a 97.5% survivorship at a mean of 6.3 years and found that varus aligned components did not affect survivorship or function. Level of evidence: III. 16. Ishikawa M, Kuriyama S, Ito H, Furu M, Nakamura S, Matsuda S: Kinematic alignment produces near-normal knee motion but increases contact stress after total knee arthroplasty: A case study on a single implant design. Knee 2015;22(3):206-212. Medline  DOI This study used a computer model to show that kinematically aligned TKAs produce greater femoral rollback and more external rotation of the component compared to mechanically aligned TKAs.

Ten cadaver knees were tested at different flexion angles to determine the normal laxity in all three planes. Greater laxity measures in 45° and 90° of flexion were found, and these findings did not support the goals of gap balancing. 18. Hommel H, Perka C: Gap-balancing technique combined with patient-specific instrumentation in TKA. Arch ­O rthop Trauma Surg 2015;135(11):1603-1608. Medline  DOI Twenty-five TKAs were prospectively followed after ­patient-specific instrumentation and gap balancing. Transverse plane femoral rotation varied from 3° internal to 6° external rotation with a 1.2-mm elevation in the joint line on average.

Using 83 magnetic resonance images with degenerative changes to simulate the risk of PCL avulsion with zero, 3°, or 5° posterior slope resection, the study concluded that those patients with more posterior slope are at lower risk of PCL avulsion after cruciate retaining TKA. 22. Fukubayashi T, Torzilli PA, Sherman MF, Warren RF: An in vitro biomechanical evaluation of anterior-posterior motion of the knee: Tibial displacement, rotation, and torque. J Bone Joint Surg Am 1982;64(2):258-264. Medline 23. Bolanos AA, Colizza WA, McCann PD, et al: A comparison of isokinetic strength testing and gait analysis in patients with posterior cruciate-retaining and substituting knee arthroplasties. J Arthroplasty 1998;13(8):906-915. Medline  DOI 24. Li G, Zayontz S, Most E, Otterberg E, Sabbag K, Rubash HE: Cruciate-retaining and cruciate-­substituting total knee arthroplasty: An in vitro comparison of the kinematics under muscle loads. J Arthroplasty 2001;16(8 suppl 1):150-156. Medline  DOI 25. Scott DF, Smith RR: A prospective, randomized comparison of posterior stabilized versus cruciate-substituting total knee arthroplasty: A preliminary report with minimum 2-year results. J Arthroplasty 2014;29(9 suppl):179-181. Medline  DOI Comparing 56 patients with a posterior-stabilized TKA to 55 TKA patients with an anterior lipped cruciate-­ substituting insert at 45 months found equal outcomes in these two groups functionally and radiographically. 26. Berend KR, Lombardi AV Jr, Adams JB: Which total knee replacement implant should I pick? Correcting the pathology: The role of knee bearing designs. Bone Joint J 2013;95-B(11 suppl A):129-132. Medline  DOI This study compared motion and manipulation rates in cruciate-retaining TKA patients with a cruciate-­retaining 3° posterior slope insert (1,334 patients), no slope and small posterior lip (803 patients), and a deep dished insert (312 patients). More manipulations occurred in the posterior lipped and 3° sloped insert. 27. Lozano-Calderón SA, Shen J, Doumato DF, Greene DA, Zelicof SB: Cruciate-retaining vs posterior-substituting inserts in total knee arthroplasty: Functional outcome comparison. J Arthroplasty 2013;28(2):234-242.e1. Medline  DOI

19. Mihalko WM, Krackow KA: Posterior cruciate ligament effects on the flexion space in total knee arthroplasty. Clin Orthop Relat Res 1999;360:243-250. Medline  DOI

A comparison of 412 cruciate-retaining to 328 posterior-­ stabilized TKA patients found that no difference in functional outcomes or patient satisfaction occurred.

20. DesJardins JD, Walker PS, Haider H, Perry J: The use of a force-controlled dynamic knee simulator to quantify the mechanical performance of total knee replacement designs during functional activity. J Biomech 2000;33(10):12311242. Medline  DOI

28. Joglekar S, Gioe TJ, Yoon P, Schwartz MH: Gait analysis comparison of cruciate retaining and substituting TKA following PCL sacrifice. Knee 2012;19(4):279-285. DOI  Medline

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17. Roth JD, Howell SM, Hull ML: Native knee laxities at 0°, 45°, and 90° of flexion and their relationship to the goal of the gap-balancing alignment method of total knee arthroplasty. J Bone Joint Surg Am 2015;97(20): 1678-1684. Medline  DOI

21. Sessa P, Fioravanti G, Giannicola G, Cinotti G: The risk of sacrificing the PCL in cruciate retaining total knee arthroplasty and the relationship to the sagittal inclination of the tibial plateau. Knee 2015;22(1):51-55. Medline  DOI

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Nine matched patients were compared who underwent TKA with either a cruciate-retaining or posterior-­ stabilized TKA, with all undergoing PCL sacrifice. No differences between the two groups occurred when comparing stair ascent and descent and gait when analyzed in a motion analysis laboratory. 29. Zhang K, Mihalko WM: Posterior cruciate mechanoreceptors in osteoarthritic and cruciate-retaining TKA retrievals: A pilot study. Clin Orthop Relat Res 2012;470(7):1855-1859. Medline  DOI This study reports that the number of mechanoreceptors in a PCL in knees with osteoarthritis does not differ when compared to PCL obtained at the time of necropsy from cruciate-retaining TKAs. 30. Mihalko WM, Lowell J, Higgs G, Kurtz S: Total knee postcam design variations and their effects on kinematics and wear patterns. Orthopedics 2016;39(3 suppl):S45-S49. Medline  DOI Using retrievals of different post-cam mechanism designs, the authors show how design variations can affect transverse plane and sagittal plane motion and wear.

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31. Indelli PF, Aglietti P, Buzzi R, Baldini A: The Insall-Burstein II prosthesis: A 5- to 9-year follow-up study in osteoarthritic knees. J Arthroplasty 2002;17(5):544549. Medline  DOI

and functional outcome in total knee arthroplasty? A randomised controlled clinical trial with 5-year follow-up. J Arthroplasty 2015;30(11):1931-1937. Medline  DOI When groups of patients with fixed or mobile bearing TKA were compared, outcomes between the two groups were similar but revision rates were higher in the patients with mobile bearings. 36. Namba R, Graves S, Robertsson O, et al: International comparative evaluation of knee replacement with fixed or mobile non-posterior-stabilized implants. J Bone Joint Surg Am 2014;96(suppl 1):52-58. Medline  DOI Using national registries to compare mobile- to fixed-­ bearing TKAs with an advanced harmonized distribution analysis found that mobile-bearing nonposterior stabilized designs had higher rates of revision. 37. Hofstede SN, Nouta KA, Jacobs W, et al: Mobile bearing vs fixed bearing prostheses for posterior cruciate retaining total knee arthroplasty for postoperative functional status in patients with osteoarthritis and rheumatoid arthritis. Cochrane Database Syst Rev 2015;2(2):CD003130. Medline Using the Cochrane database, the authors found 19 studies to analyze and that there was moderate to low-quality evidence to suggest that mobile-bearing implants have a similar effect on knee pain, revision, mortality, and quality of life compared with fixed posterior cruciate-retaining implants.

32. Walker PS, Lowry MT, Kumar A: The effect of geometric variations in posterior-stabilized knee designs on motion characteristics measured in a knee loading machine. Clin Orthop Relat Res 2014;472(1):238-247. Medline  DOI

38. Komistek RD, Dennis DA, Mahfouz M: In vivo fluoroscopic analysis of the normal human knee. Clin Orthop Relat Res 2003;410:69-81. Medline  DOI

Using a custom testing machine, the authors tested four posterior-stabilized TKA designs and compared with one experimental asymmetric design. Variations from symmetric rollback in the current designs to more medial pivot in the experimental design were reported.

39. Ploegmakers MJ, Ginsel B, Meijerink HJ, et al: Physical examination and in vivo kinematics in two posterior cruciate ligament retaining total knee arthroplasty designs. Knee 2010;17(3):204-209. Medline  DOI

33. Shimizu N, Tomita T, Yamazaki T, Yoshikawa H, Sugamoto K: In vivo movement of femoral flexion axis of a single-radius total knee arthroplasty. J Arthroplasty 2014;29(12):2407-2411. Medline  DOI

Comparison of the PFC Sigma to Continuum Knee System PS TKAs was carried out using fluoroscopic kinematic analysis. This design showed less tibial rotation during flexion and more anterior sliding of the femur on the tibia.

Twenty TKA patients underwent fluoroscopic analyses with a Triathlon PS implant. No paradoxical motion was reported in up to 70° of flexion.

40. Mihalko WM, Williams JL: Total knee arthroplasty kinematics may be assessed using computer modeling: A feasibility study. Orthopedics 2012;35(10suppl):40-44. Medline  DOI

34. Ishii Y, Noguchi H, Takeda M, Sato J, Toyabe S: Posterior condylar offset does not correlate with knee flexion after TKA. Clin Orthop Relat Res 2013;471(9):2995-3001. Medline  DOI

Using a computational model and computer navigation registration landmarks, the study reported similar intraoperative kinematics along with similar comparisons in the literature.

One hundred seventy TKA patients were analyzed 1 year after surgery with either a PCL-retaining or PCL-sacrificing implant. Differences in posterior condylar offset did not seem to correlate with knee flexion in either group.

41. Schmidt R, Komistek RD, Blaha JD, Penenberg BL, Maloney WJ: Fluoroscopic analyses of cruciate-retaining and medial pivot knee implants. Clin Orthop Relat Res 2003;410:139-147. Medline  DOI

35. Fransen BL, Hoozemans MJ, Keijser LC, van Lent ME, Verheyen CC, Burger BJ: Does insert type affect clinical

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Chapter 10

Implant Designs of Total Knee Arthroplasty Kartik Mangudi Varadarajan, PhD  Daniel J. Holtzman, MD  Guoan Li, PhD  Jeffrey Lange, MD  Steven B. Haas, MD  Harry E. Rubash, MD  Andrew A. Freiberg, MD

Abstract The continued development of implant geometries and materials used in total knee arthroplasty is motivated by the recognition of patient dissatisfaction, increased use in young and active patients, and concerns regarding metal hypersensitivity. Single-radius and multiradius femoral designs appear to be associated with equivalent clinical outcomes. Anatomic tibial trays can reduce the likelihood of internal rotation if tibial coverage is maximized to guide placement. Recent meta-analyses and registry studies suggest equivalent outcomes for all-polyethylene and metal-backed tibial components. Anatomic or biomimetic articular surfaces together with anterior cruciate ligament retention or substitution may be key to restoring normal kinematics following total knee arthroplasty. Restoration of the native joint line by using surgical technique or asymmetric thickness components may also play an important role in improving function following TKA. Several materials have shown promise as alternatives to cobalt-chromium-molybdenum alloys. Bulk ceramics and oxidized zirconia have shown particularly excellent mid- to long-term outcomes and may be viable options for patients with suspected metal hypersensitivity.

Introduction Total knee arthroplasty (TKA) implant designs continue to evolve, given that 20% to 30% of patients are dissatisfied with how their knee feels and functions after surgery; use of these procedures has increased in active patients younger than 65 years; and concerns exist regarding metal hypersensitivity in some patients. New implant technologies, together with improvements in technique and instrumentation, can hopefully result in a more normal-feeling knee postoperatively, with longevity extending to the second and third decade. It is important for the orthopaedic surgeon to be aware of the considerations and developments related to implant geometry and implant materials, with a focus on issues that continue to be debated and new technologies that are being explored.

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Keywords: anatomic articular surface; anterior cruciate ligament; ACL function; anatomic joint line; all-polyethylene tibial component; ceramics

Implant Geometry The implant geometry directly influences joint biomechanics, including function of the native soft tissues, tibiofemoral kinematics, and patellar tracking. Previously, sex-specific implants were proposed to better fit male or female knee anatomy. Subsequent research has not supported the need for sex-specific designs, but instead has shown a need for size-specific aspect ratios and/or provisions for sufficient implant sizes. Similarly, although high-flexion designs reduce tibiofemoral contact stresses in deep flexion, they do not provide increased range of motion (ROM). In addition, these newer designs do not treat the underlying kinematic limitations of contemporary implants, which have been associated with functional limitations and patient dissatisfaction. One study reported that patients who underwent TKA have greater difficulty performing activities such as kneeling, carrying loads, playing tennis, dancing, and gardening compared with their age-matched peers; only 40% of the functional deficit seemed attributable to the normal effects of aging.1 Research and development efforts are ongoing to

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Figure 1

Photographs of a single-radius total knee arthroplasty femoral component (Triathlon, Stryker) (A) with a constant radius over 10° to 110° of flexion (red outline) and a multiradius femoral component (Genutech, Surgival) (B) with one radius from 0° to 45° of flexion (black outline) and a different radius from 45° to 130° of flexion (orange outline). (Reproduced with permission from Hinarejos P, Puig-Verdie L, Leal J, et al: No differences in functional results and quality of life after single-radius or multiradius TKA. Knee Surg Sports Traumatol Arthrosc 2015;12:1-7.)

2: Knee

create implant designs that can provide more normal kinematics via modifications of the femoral and tibial articular surfaces, the provision of asymmetric components to reduce rotational malpositioning, and the restoration of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) function via retention or substitution. Femoral Implant Single-Radius Versus Multiradius Designs

Both single-radius and multiradius femoral implant designs are commercially available (Figure 1). Multiradius

designs use a changing radius of curvature with increased knee flexion that results in a center of rotation that shifts through the ROM. Single-radius designs have a consistent radius of curvature throughout the flexion-extension arc and a more posterior center of rotation, which theoretically creates more consistent soft-tissue/collateral ligament tension to minimize instability in mid flexion and increases quadriceps muscle strength. A 2015 study examined three cohorts of patients (16 patients after single-radius TKA, 16 patients after multiradius TKA, and 16 healthy control patients) in a gait analysis labor­atory.2 Preoperatively, no

Dr. Varadarajan or an immediate family member has received royalties from Stryker; serves as a paid employee of Merck; serves as a paid consultant to CeramTec and Orthopaedic Technology Group; has stock or stock options held in Merck and Orthopaedic Technology Group; and serves as a board member, owner, officer, or committee member of the Orthopaedic Research Society. Dr. Li or an immediate family member has received royalties from Stryker. Dr. Haas or an immediate family member has received royalties from Smith & Nephew and Innovative Medical Products; is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew; serves as a paid consultant to Smith & Nephew; has stock or stock options held in OrthoSecure; has received research or institutional support from Smith & Nephew; and has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from APOS Medical & Sports Technologies. Dr. Rubash or an immediate family member has received royalties from CeramTec and Stryker; serves as a paid consultant to Flexion Therapeutics and Pacira Pharmaceuticals; has stock or stock options held in Orthopaedic Technology Group; and serves as a board member, owner, officer, or committee member of the Hip Society. Dr. Freiberg or an immediate family member has received royalties from Biomet and Zimmer; serves as a paid consultant to Zimmer, Biomet, and Medtronic; and has stock or stock options held in ArthroSurface and Orthopaedic Technology Group. Neither of the following authors nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Holtzman and Dr. Lange.

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Figure 2

Illustrations of the distal femur and proximal tibia in the coronal plane demonstrate symmetric distal femoral condylar resurfacing, which causes depression of the lateral joint line. A, The area of planned resection for a standard total knee arthroplasty (TKA) is between the two red lines. B, The area of planned resection noted in A has been replaced by a schematic of a TKA (shaded area). Note the medial joint line remains in its anatomic location, and the lateral joint line is translated distal to its anatomic location. Lines parallel to the cut proximal tibial surface clarify the relationship between the native and resurfaced joint line positions medially (dotted line) and laterally (dashed line). L = lateral, M = medial.

© 2017 American Academy of Orthopaedic Surgeons

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significant differences in gait cycle parameters existed between patients in the single-radius and multiradius groups. Postoperatively, several significant differences were noted between the patients in the multiradius group and control patients in several gait parameters, including increased knee extension and decreased power absorption in the multiradius group. No significant differences between the single-radius group and control patients were detected. Despite these findings, no functional differences were observed in patient-­reported outcome measures. A lack of functional difference between single-radius and multiradius designs has been reported. A prospective cohort study with a standardized surgical and rehabilitation protocol reported on 250 patients who underwent single-radius TKA and 224 patients who underwent multiradius TKA with 5-year follow-up.3 No significant differences existed between the single-radius and multiradius groups at 1 and 5 years following surgery in Knee Society scores, Medical Outcomes Study 36-Item Short Form physical scores, postoperative ROM, or patient satisfaction. In addition, a recent meta-analysis of 15 studies compared single-radius and multiradius TKA

designs and found no difference in Knee Society scores, knee flexion, complications, isometric peak torque of the knee, or survival rates.4 Thus, the theoretical advantages of a single-radius design are not supported by available clinical data. This finding may be because the actual geometric difference between single-radius and multiradius femoral designs for most of the active flexion range (10° to 110°) is small. Implant systems with single-radius versus multiradius designs also vary substantially in the geometry of other components, such as the tibial articular geometry. Therefore, it may be difficult to ascertain the effects of femoral design alone from clinical data. Restoration of the Anatomic Joint Line

Historically, the two primary approaches to coronal plane positioning of the joint line were anatomic and functional alignment. Anatomic alignment, along with its modern iteration termed kinematic alignment, aims to restore the natural joint line orientation to promote natural knee mechanics. Functional alignment, also termed mechanical alignment, is the prevailing convention and aims to create a joint line perpendicular to the overall mechanical axis

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Figure 3

Illustrations of the distal femur and proximal tibia in the coronal plane demonstrate asymmetric distal femoral condylar morphology matched using implant design. A, The area of planned resection for a standard total knee arthroplasty (TKA) is located between the two red lines. B, The area of planned resection as noted in A has been replaced by a schematic of a TKA with asymmetric distal femoral condylar surfaces (shaded area). Asymmetry of the femoral component is matched by asymmetry of the tibial component, restoring both the medial and lateral joint lines to their anatomic locations. Lines parallel to the cut proximal tibial surface clarify the relationship between the native and resurfaced joint line positions medially (dotted line) and laterally (dashed line). L = lateral, M = medial.

of the lower limb. This approach is thought to load each compartment equally, avoiding an overload of the tibial component medially.5 Although mechanical alignment has produced excellent results in millions of patients, natural knee kinematics are not maintained when this method is used. This is, in part, because although the implants generally have equal medial and lateral condylar thicknesses, the corresponding bone cuts have asymmetric thicknesses. For example, in a typical varus knee, approximately 9 mm of bone is removed from the distal medial femoral condyle, which equals the implant thickness, and approximately 7 mm of bone is removed from the distal lateral femoral condyle, which is less than the thickness of the implant. In this situation, the medial joint line will remain anatomic but the lateral joint line will be displaced distally by approximately 2 mm with standard femoral implants (Figure 2). Joint line depression is not ideal because it is linked to patellofemoral pain, subluxation, and diminished functional gains at deviations as small as 3 mm

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of depression.6 Alternatively, if distal femoral resection increases by 2 mm, the lateral joint line will remain anatomic and the medial joint line will be elevated. Joint line elevation also is not ideal because it is linked to patellar impingement on the tibial component, midflexion instability, and patellofemoral pain at deviations as small as 5 mm of elevation.6 Furthermore, because mechanical alignment does not re-create natural knee kinematics, collateral ligament tension and strain are significantly altered during knee ROM.7 One approach to restoration of the anatomic joint line is to use standard nonanatomic implants positioned parallel to the native joint line. However, placing nonanatomic implants in an anatomic coronal position can be problematic. Placing the tibial component in varus has been associated with high failure rates in many studies.8 In addition, placing the tibial component in varus necessitates internal rotation of the femoral component to create a symmetric flexion gap, which elevates the lateral anterior femoral flange and rotates the trochlear groove

© 2017 American Academy of Orthopaedic Surgeons

Chapter 10: Implant Designs of Total Knee Arthroplasty

Figure 4

Illustration depicts anatomic, symmetric, and asymmetric tibial trays overlaid on a proximal tibial surface. The maximum tibial coverage and resulting rotation for each tray design are also indicated. (Reproduced with permission from Stulberg SD, Goyal N: Which tibial tray design achieves maximum coverage and ideal rotation: Anatomic, symmetric, or asymmetric? An MRI-based study. J Arthroplasty 2015;30[10]:1839-1841.)

Tibial Tray Symmetric/Asymmetric Versus Anatomic Design

Tibial tray design has the potential to influence tibial coverage and rotational alignment. In practice, coverage

© 2017 American Academy of Orthopaedic Surgeons

and rotation may be conflicting, prompting reduction of the tibial component size and coverage to optimize rotational alignment. Increased recognition of population and ethnic differences in proximal tibial morphology has resulted in more tibial tray implant design options. Currently, symmetric, asymmetric, and anatomic designs are commercially available (Figure 4). A 2014 study compared proximal tibial morphology obtained from the CT scans of Caucasian cadavers and living Indian, Korean, Chinese, and Japanese subjects with six contemporary TKA designs.11 Compared with asymmetric and symmetric designs, the anatomic design demonstrated better conformity to tibial size/shape and tibial coverage (92% versus 85% to 87%, respectively), and a lower incidence of downsizing (3% versus 39% to 60%, respectively) to ensure rotational alignment. An MRI-based study of symmetric, asymmetric, and anatomic tibial trays from a single manufacturer showed significantly higher proximal tibial coverage with the anatomic design (80.8%) compared with the symmetric (76.3%) and asymmetric (75.8%) designs when rotational alignment was constrained to the anterior-posterior axis.12 In contrast, another 2014 study found similar tibial coverage for symmetric, asymmetric, and anatomic trays aligned to the tibial anterior-posterior axis,13 as well as similar variations in rotational position when maximizing tibial coverage. However, in that study, symmetric and asymmetric designs were biased toward internal rotation and the anatomic design was biased toward external rotation, which indicates that anatomic designs may provide only a slight advantage regarding tibial coverage. However, anatomic designs may reduce the incidence of internal tibial rotation if maximal tibial coverage is used to guide tray placement.

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medially. Furthermore, by placing the femoral component in relative valgus, the proximal trochlear groove is shifted medially, which potentially predisposes the patella to tilt and maltracking.9 Despite these issues, proponents of kinematic alignment report reasonable short-term results.10 Long-term studies are necessary to clarify the role of this method in TKA. Instead of placing components in anatomic position, another option is to restore the anatomic joint line using the implant design. This restoration is achieved in some designs by using the concept of anatomic contour matching to match the thickness of the bone removed to the thickness of the bone replaced. To restore an anatomic varus joint line orientation of 3°, the lateral side of the tibial insert is thicker than the medial side. Concomitantly, the distal medial side of the femoral component is thicker than the distal lateral side. Using asymmetric implant thicknesses allows these designs to more closely match the normal anatomy of the typical femur and tibia while using standard mechanical alignment bone cuts (Figure 3). Thus, an anatomic joint line can be achieved while maintaining a tibial cut perpendicular to the tibial mechanical axis, thereby minimizing shear forces and the potential for mechanical failure at the tibial interface. Restoration of the anatomic joint line in conjunction with other design features such as anatomic tibial articular geometry and bicruciate substitution, may contribute to the reproduction of near-normal knee kinematics.

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All-Polyethylene Versus Modular Tibial Components

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All-polyethylene tibial components have been used since the earliest tibial component designs were developed. However, most knee implants currently use modular metal-backed tibial components because of advantages such as intraoperative flexibility, the potential for isolated bearing exchange, and the availability of a press-fit fixation option. Modular metal-backed tibial components also are proposed to diminish stress and strain at the implant-cement interface. Initial poor results and early failures for all-polyethylene tibial components were attributed to surgical technique and implant design problems, specifically, the lack of articular congruity of the tibial component. However, recent meta-analyses and registry-level studies suggest that clinical outcomes of all-polyethylene tibial components are equivalent to those of metal-backed components. A systematic review and meta-analysis of 1,798 TKA implants in 12 studies published from 1990 to 2011 identified all-polyethylene tibial components as one of the treatment arms.14 Although no findings were significant, respective risk reductions of 29% and 14% were identified at 10 and 15 years after the index procedure for revision for all-polyethylene components compared with metal-backed components. Furthermore, no significant difference was found in functional outcome or adverse events between the all-polyethylene and metal-backed groups. Additional meta-analyses of previously published studies also demonstrated no significant differences in functional outcomes and complications between all-­polyethylene and metal-backed tibial components.15 A 2013 study published data from a large community-­based total joint registry of 27,657 patients who underwent TKA with the same implant (91.7% in the metal-backed group and 8.3% in the all-polyethylene group).16 The surface geometry of the tibial implant was the same for both the metal-backed and all-polyethylene tibial components. The revision rate was lower for all etiologies in the all-polyethylene group than in the metal-backed group (1.95% versus 2.17%, P < 0.001). After adjusting for age and sex, the risk of revision for all etiologies of an all-polyethylene tibial component was 0.51 times higher than the risk of revision for a metal-backed component (95% confidence interval: 0.33-0.78). A 2014 study published the comparative revision rates of cruciate-­retaining all-­polyethylene and metal-backed tibial components performed with the same implant with identical surface geometry in 27,733 patients from the Swedish Knee Arthroplasty Register (median follow-up, 4.5 years; 57.7% metal-backed components, 42.3% all-polyethylene components).17 Unadjusted 10-year survival was 96.6% for the metal-backed tibial component and 97.2% for the

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all-polyethylene tibial component (P = 0.002). Cox multiple regression analysis demonstrated that all-polyethylene tibial components had a lower risk of revision for any reason, with an adjusted relative risk of 0.75 (95% confidence interval: 0.64-0.89), compared with metal-backed tibial components. In addition, all-polyethylene tibial components may provide the added benefit of reduced costs. One study showed a 20% to 30% reduction in cost when using all-polyethylene components compared with metal-backed components; another study calculated $95,000 in savings on implant costs for every 100 patients who received an all-polyethylene component instead of a metal-backed component.18,19 PCL Function: Retention, Substitution, or Sacrifice The debate regarding the merits of PCL retention in cruciate-­retaining designs versus PCL substitution in posterior-stabilized designs has been long-standing. However, no clinically relevant differences have been found in ROM, pain, clinical, or radiologic outcomes for cruciate-retaining versus posterior-stabilized designs.20 In a cruciate-substituting or ultracongruent design, the PCL is sacrificed, with no cam-post mechanism (unlike posterior-stabilized designs) to substitute its function. One potential advantage of ultracongruent designs over posterior-stabilized designs is greater bone preservation resulting from the absence of a femoral box cut. Potential disadvantages of ultracongruent designs include increased wear resulting from greater contact area and reduced ROM because of reduced rollback or greater paradoxical anterior sliding. These designs generally share the same tibial articular geometries as their cruciate-retaining counterparts, except for a higher anterior lip (and often a higher posterior lip), which is designed to minimize anterior femoral sliding in flexion. However, some studies show greater anterior femoral translation in flexion for ultracongruent designs compared with posterior-stabilized and cruciate-retaining designs, 21-24 indicating that the anterior lip may not fully compensate for the stability provided by the PCL or the post-cam mechanism. No significant differences in clinical outcomes, including ROM, function scores, and radiographic evaluation, have been noted for ultracongruent versus cruciate-retaining or posterior-­stabilized designs.22-24 Similarly, a multicenter study found no difference in 10-year survivorship for ultracongruent, cruciate-retaining, or posterior-stabilized TKA designs.25 The similar outcomes among ultracongruent, cruciate-retaining, and posterior-stabilized designs may partly be explained by their relatively similar kinematics,

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Figure 5

Illustration depicts simulated deep knee bend kinematics of a biomimetic cruciate-retaining implant (Biomimetic CR) and three contemporary cruciate-retaining implants (NextGen CR, ZimmerBiomet; Vanguard CR, ZimmerBiomet; and Triathlon CR, Stryker). The biomimetic cruciate-retaining implant exhibited an overall medial pivot with greater lateral rollback compared with medial rollback, and no paradoxical anterior sliding. Contemporary cruciate-retaining implants exhibited no medial pivot, the NexGen cruciate-retaining implant exhibited paradoxical anterior sliding, and the Triathlon cruciate-retaining implant exhibited minimal rollback. (Reproduced with permission from Varadarajan KM, Zumbrunn T, Rubash HE, Malchau H, Li G, Muratoglu OK: Cruciate retaining implant with biomimetic articular surface to reproduce activity dependent kinematics of the normal knee. J Arthroplasty 2015;30[12]:2149-2153.)

Tibial Articular Surface One important factor responsible for kinematic limitations of contemporary implants is the nonanatomic tibial articular geometry.26 In the native knee, the medial tibial plateau has a shallow dish profile, and the lateral plateau is convex. This geometry, coupled with the differential stability of the medial versus lateral menisci, results in differential anterior-posterior excursion of the medial and lateral femoral condyles during flexion. However, the ball-in-socket analogy commonly used to describe the medial condyle is only partially true because its motion is not completely restricted. During activities of limited flexion such as walking or stair climbing, the anterior-posterior motion of the medial and lateral condyles can be similar, resulting in lateral or variable

© 2017 American Academy of Orthopaedic Surgeons

pivot patterns.27,28 Nevertheless, for its full ROM and during high-flexion activities, the knee shows an overall medial pivot with greater rollback of the lateral femoral condyle.28 In contrast to asymmetric native tibial anatomy, most contemporary implants (for example, cruciate-retaining and posterior-stabilized implants) have identical medial and lateral articular geometries. 29 A notable exception is the ball-in-socket medial pivot concept that was first introduced in the mid 1990s. Several newer versions of these designs that maintain this original philosophy have been introduced in recent years. In vivo and in vitro studies show that the design objectives of minimizing medial condyle motion and paradoxical anterior sliding are achieved via these ball-in-socket implants.29,30 However, the extent of medial pivot rotation and lateral condyle rollback are smaller in magnitude compared with normal knees.29,30 This feature may be a result of the prominent posterior lip or the absence of normal lateral convexity, which limits lateral condyle rollback. Other concerns with the strict ball-in-socket concept are the inability to accommodate normal pivot center variations during low-flexion activities and conflicts with the PCL if used in the cruciate-retaining setting.27,31,32 The conflict with native PCL may explain why ball-in-socket implants are generally indicated for use with a PCL-sacrificing technique.29,30 Thus, development

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compared with their kinematic differences from the preoperative or normal condition. Two separate studies both found paradoxical anterior translation approximately 2 mm greater for ultracongruent designs than for posterior-stabilized and cruciate-retaining designs.21,22 In contrast, another study measured the intraoperative kinematics of patients receiving ultracongruent implants and reported 8 mm of anterior translation of the medial condyle and 20 mm of anterior translation of the lateral condyle relative to the preoperative condition.24

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Figure 6

Illustration depicts in vivo medial and lateral condyle motion in patients with a bicruciate-substituting implant (Journey, Smith & Nephew) during deep knee bend activity. Although the surgical technique affected the kinematics, the characteristic motion patterns of normal knees, including greater lateral condyle rollback and absence of anterior sliding, were typically observed. (Reproduced with permission from Victor J, Mueller JK, Komistek RD, Sharma A, Nadaud MC, Bellemans J: In vivo kinematics after a cruciate-substituting TKA. Clin Orthop Relat Res 2010;468[3]:807-814.)

continues of advanced articular surfaces that allow restoration of activity-dependent kinematics of the knee. In 2015, a new biomimetic technique was described to create articular surfaces directly from the in vivo kinematics of healthy knees, which was achieved by moving the femoral component in virtual space along the in vivo kinematics to carve a compatible biomimetic tibial articular surface.26 Theoretically, this method accounts for normal anatomy and kinematics, allows hand-in-hand design of femoral and tibial articular surfaces, and incorporates the effect of surgical placement. The resulting biomimetic surface has an anatomic profile, including a shallow medial surface similar to some conventional implants, and a convex lateral plateau with a relatively low anterior and minimal posterior lip. Progressive deviations from the biomimetic geometry resulted in increasingly abnormal kinematics during a simulated knee bend.26 In another study, a biomimetic cruciate-retaining implant was found to more closely mimic normal kinematic patterns

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than contemporary cruciate-retaining implants during various simulated activities33 (Figure 5). The biomimetic cruciate-­retaining implant particularly showed medial pivot motion during the deep knee bend and chair sit while accommodating pivot center variations during stair ascent. This concept has not been evaluated in vivo. In contrast, an ACL-/ PCL-substituting (bicruciate-­substituting) implant with anatomic tibial articular surfaces has been available since 2005, and a cruciate-­retaining version of the same design was recently introduced (Figure 6). Positive results regarding the restoration of normal kinematic patterns have been reported for the bicruciate-substituting design. One study reported profiles of the patellar tendon angle and patellar flexion for the bicruciate-substituting knee to be more normal than other TKA designs.34 During a deep knee bend activity, another study measured medial and lateral condyle rollback of 14 and 23 mm, respectively, in bicruciate-substituting knees. Average axial rotation

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Figure 7

Illustration depicts motion of the medial and lateral femoral condyles relative to the tibia of a biomimetic bicruciate-retaining (Biomimetic BCR), contemporary cruciate-retaining (NextGen CR, ZimmerBiomet), contemporary bicruciate-retaining (TKO BCR, BioPro), and biunicompartmental (MCK Bi-Uni) implants during a simulated deep knee bend. Unlike the cruciate-retaining implant, contemporary bicruciate-retaining and biunicompartmental implants did not exhibit paradoxical anterior sliding. However, these implants did not restore normal differential medial and lateral rollback like the biomimetic bicruciate-retaining implant. (Reproduced with permission from Zumbrunn T, Varadarajan KM, Rubash HE, Malchau H, Li G, Muratoglu OK: Regaining native knee kinematics following joint arthroplasty: A novel biomimetic design with ACL and PCL preservation. J Arthroplasty 2015;30[12]:2143-2148.)

patterns were similar but lower in magnitude than in normal knees35 (Figure 6).

Currently, three strategies are being explored to incorporate ACL function in TKA: native ACL and PCL retention, ACL substitution and native PCL retention, and ACL and PCL substitution. ACL and PCL Retention Retention of the ACL and PCL during TKA is a concept that was introduced in the 1970s (for example, the Geomedic knee and the anatomic knee). However, ACL and PCL retention did not attain widespread acceptance because of perceived difficulties in balancing both the ACL and PCL, concerns regarding the viability of the ACL in the arthritic knee, fracture of the tibial bony eminence, polyethylene wear, and the strength of the tibial baseplate.36 Many of these challenges were specific to a few designs as well as older-generation polyethylene, which was susceptible to oxidative degradation. Avoiding keels in the tibial baseplate that can weaken the tibial bone island, minimizing the removal of cortical bone anterior to the tibial eminence, and avoiding eminence undercutting

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ACL Function

can help reduce the risk of bone island failure. Despite the aforementioned challenges, some clinical series have shown excellent long-term outcomes. The clinical aspects of ACL retention are beyond the scope of this chapter. Patients with bicruciate-retaining implants generally have been reported to exhibit more normal kinematics than patients with ACL-sacrificing implants. However, a 2015 study noted that the analysis of available kinematic data shows that contemporary bicruciate-retaining implants do not fully restore normal kinematics.36 Abnormal early posterior femoral shift and subsequent paradoxical anterior sliding, which are observed with ACL-sacrificing implants, are generally not observed with contemporary bicruciate-retaining implants.36,37 However, as with ACL-sacrificing implants, contemporary bicruciate-retaining implants also show symmetric medial/lateral condylar rollback, and thus, minimal axial rotation.36,37 The 2015 study used dynamic computer simulations to compare the kinematics of a biomimetic bicruciate-retaining design with an anatomic tibial articular surface with that of contemporary bicruciate-­retaining and cruciate-retaining implants36 (Figure 7). The biomimetic bicruciate-retaining implant exhibited kinematics most similar to healthy knees. Another study compared biomimetic bicruciate-retaining and biomimetic

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Figure 8

Illustration depicts mean femoral rollback of the medial and lateral condyles during a simulated deep knee bend for an anterior cruciate ligament (ACL)–substituting and posterior cruciate ligament (PCL)–retaining (ASCR), two ACL-retaining (BCR-A, BCR-B), and a contemporary cruciate-retaining (CR) TKA. Both the ASCR and ACL-retaining designs avoided the abnormal early posterior shift and subsequent paradoxical anterior slide that were observed in the cruciate-retaining implant. (Reproduced with permission from Varadarajan KM, Zumbrunn T, Duffy MP, Rubash HE, Malchau H, Muratoglu OK: Poster No. 1885. Is retention of native ACL the only option for addressing abnormal anteroposterior kinematics of cruciate retaining TKA? Proceedings of the 62nd Annual Meeting of the Orthopaedic Research Society. Rosemont, IL, Orthopaedic Research Society, 2016, p 146.)

cruciate-retaining implants and reported that the absence of the ACL in the cruciate-retaining design resulted in a more posterior location of the femur and reduced femoral rollback.26 However, restoration of the native articular geometry in the biomimetic cruciate-retaining implant preserved medial rotation features, which may indicate that restoration of the native anatomy together with ACL preservation is required to achieve kinematics close to those of the native knee.26

used dynamic simulations to compare the kinematics of the ASCR design with ACL-retaining and ACL-­sacrificing (that is, cruciate-retaining) implants during deep knee bend, chair sit, stair ascent, and walking. 39 As with ACL-retaining implants, the ASCR design provides kinematic improvements over contemporary ACL-sacrificing implants by reducing abnormal early posterior femoral shift and avoiding paradoxical anterior sliding. However, this concept has not been evaluated clinically.

ACL Substitution

ACL and PCL Substitution

ACL Substitution and PCL Retention

In a bicruciate-substituting design, ACL and PCL function are substituted using anterior and posterior cam-post interaction, respectively. The bicruciate-­substituting concept can be considered as an extension of the posterior-stabilized philosophy that substitutes not only for the missing PCL but also for the ACL. First-­generation bicruciate-substituting designs were introduced in 2005 and showed promising kinematic results. Several in vivo studies showed more normal kinematics than contemporary TKA, including the magnitude of internal tibial rotation and posterior femoral rollback as well as the absence of paradoxical anterior sliding34,35 (Figure  6). Reported rates of clinical complications were higher than expected, including dislocation and

An alternative to native ACL retention is to substitute its function to avoid the potential challenges discussed previously and to provide an option for patients with an absent or nonfunctional ACL at surgery (approximately 14% to 75% of patients).38 The concept of an ACL-substituting and PCL-retaining implant (ASCR) has been proposed recently as an evolution of the cruciate-retaining implant in which the ACL is sacrificed with no mechanism to substitute for its function.39 In the ASCR implant, the anterior surface of a post on the tibia engages with the femoral intercondylar notch in low flexion to substitute for the absent ACL (Figure 8). The tibial post also is designed to accommodate the native PCL. A 2016 study

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iliotibial band syndrome.40,41 These complications seem to be related to insufficient jump height, excessively forced rollback by posterior cam, and a prominent anterior femoral flange.42 However, no complications were reported regarding fracture of the bicruciate-substituting tibial post or wear of the anatomic tibial articular surface. Second-generation bicruciate-substituting designs have been introduced to address these design issues. Additional studies are needed to assess the clinical significance of these design improvements.42 Implant Materials The most commonly used materials in TKA implants are cobalt-chromium-molybdenum (CoCrMo) alloy for the femoral component, conventional (minimally cross-linked or non–cross-linked) ultra-high–molecular-weight polyethylene (UHMWPE) for the tibial insert, and titanium alloy for the tibial baseplate. However, the pursuit of improved implant survivorship via the reduction of polyethylene damage and concerns regarding metal hypersensitivity have motivated the exploration of alternative materials. Clinical and registry studies continue to monitor the long-term performance of highly cross-linked UHMWPE, which was introduced in the early 2000s, and newer antioxidant-stabilized polyethylene, which was introduced in 2008.

© 2017 American Academy of Orthopaedic Surgeons

Ceramicized Metals TKA implants with various ceramic coatings are currently in clinical use, including titanium nitride (TiN) on Ti6Al4V (a grade 5 titanium alloy), TiN on cobalt-chromium (CoCr), zirconium nitride (ZrN)–coated CoCr, and titanium niobium nitride (TiNbN)–coated CoCr. Although many preclinical studies indicate favorable tribologic properties (for example, high scratch resistance, low coefficient of friction, less UHMWPE wear) of these ceramic coatings, other studies have not replicated these findings and concerns have been noted regarding loss of coating and increased wear.47 However, the coating process may have a substantial effect on coating performance. One particular ZrN coating technology uses a top coat of ZrN, five layers of chromium nitride–chromium carbonitride (CrN-CrCN), and a thin chromium bond coat on top of a standard CoCr alloy (overall thickness, 3.5 to 5.0 μm).48 The multilayer coating provides a gradient between the hard coating and the relatively soft substrate to improve the mechanical integrity of the coating. A 2011 study reported no scratches, pitting, or coating damage during a 3-million-cycle knee simulator study of a mobile-bearing implant with ZrN-coated metallic components created with this coating technology.48 A few recent studies have published clinical performance data for such ceramic-coated knee implants. A 2015 retrospective study compared short-term (mean follow-up, 2 years) clinical results for a TiNbN-coated implant with CoCr implants of the same design. This study found no differences in clinical, radiographic, or patient-reported outcomes, and no patients underwent revision in either group.49 A 2014 retrospective study of 305 TiN-coated mobile-bearing implants reported 10-year survivorship of 95.1% with revision for any reason as the end point and 99.1% with revision for aseptic loosening as the end point.50 Oxidized zirconium (OxZr) knee implants were introduced in 1997.51 Unlike the ceramic coating applied to a metal substrate, OxZr is created via thermal diffusion, which transforms the surface of wrought zirconium-niobium (2.5% niobium) alloy to a ZrO2 (monoclinic) layer approximately 5 μm thick. Although numerous laboratory wear studies have demonstrated a reduction in polyethylene wear with OxZr versus CoCr femoral components (range, 42% to 85%), until recently, in vivo data have been lacking.51 That recent retrieval study found significantly lower femoral component roughness as well as lower damage scores for

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Bulk Ceramics Ceramics have several advantages, including reduced coefficient of friction, increased lubricity due to reduced wetting angle, high hardness and abrasion resistance, and excellent biocompatibility. In the past 5 years, mid- to long-term clinical data have been published for several ceramic TKA implants. One study reported 5-year survivorship of 98.6% with no revisions for aseptic loosening, osteolysis, or ceramic fractures for an alumina medial-pivot TKA.43 Another study published 10-year clinical results for an alumina ceramic implant that has been used in Japan since 1992.44 At a mean follow-up of 11.7 years, the mean Knee Society score was 93.3, survivorship with any reoperation or radiographic failure as an end point was 95.9%, and no fractures of the ceramic femoral component occurred. Another study reported on the clinical outcomes of a ceramic TKA with an alumina matrix composite femoral component that was strengthened with yttria-stabilized tetragonal zirconia particles.45 At 5-year follow-up, implant survivorship was 96.0%, with no implant migration or loosening. In one case, a midline longitudinal crack was noted on the ceramic femoral component following a traumatic event, and two fractures of the femoral component that occurred

during intraoperative impaction were reported. Subsequent analysis showed hard impaction at high velocity and the femoral resection angle to be likely causes of failure.46

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both femoral components and polyethylene inlays with OxZr compared with matched paired CoCr TKAs.51 A 2011 study published results of a randomized controlled trial with patients with bilateral TKA who received a CoCr femoral implant in one knee and an OxZr implant in the contralateral knee.52 At 5-year follow-up, no significant differences were reported between the two groups regarding mean Knee Injury and Osteoarthritis Outcome Scores or radiologic evaluation findings. In a retrospective review of 109 OxZr TKAs performed in 82 patients with a mean follow-up of 5.9 years, no revisions were performed for wear, loosening, osteolysis, or infection.53 The mean Knee Society score was 92 points (range, 49 to 100 points) and the mean function score was 81 points (range, 30 to 100 points). A 2014 study reported 10-year results of a prospective study for 84 patients at final follow-up.54 Overall survivorship was 97.8%; two knees needed revision for femoral component loosening. The mean knee score was 84 points (range, 64 to 100 points) and the mean function score was 83 points (range, 55 to 100 points). Summary

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Implant design has a major influence on both short- and long-term outcomes following TKA. Important issues pertaining to implant geometry and materials are currently being debated, and new technologies are under investigation. Available evidence does not indicate superiority of single-radius or multiradius femoral designs in relation to clinical outcomes. Anatomic tibial trays may offer only a slight advantage for increased tibial coverage; however, they could reduce the probability of internal rotation if attainment of maximal tibial coverage is used to guide tray placement. Cost advantages coupled with equivalent outcomes to metal-backed components could increase the use of all-polyethylene tibial components. PCL-retaining (cruciate-retaining), PCL-substituting (posterior-stabilized), and PCL-sacrificing (ultracongruent) designs seem to have similar clinical outcomes and long-term survivorship. However, the high anterior tibial lips in ultracongruent designs may not fully compensate for PCL function, resulting in increased anterior femoral sliding. Contemporary implants show significant kinematic alterations relative to the preoperative and normal knee, which may partly explain the similar patient outcomes observed with cruciate-retaining, posterior-stabilized, and ultracongruent designs. Provision of anatomic or biomimetic articular surfaces together with ACL retention or substitution may be key to restoring normal kinematics

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following TKA. However, such new implant designs do not preclude the importance of surgical technique. Techniques designed to facilitate more normal collateral ligament function via anatomic joint line restoration may play a crucial role in achieving normal knee function following TKA. Several materials continue to be evaluated as an alternative to CoCrMo alloy. Bulk ceramics and oxidized zirconia have demonstrated excellent mid- to long-term outcomes and may be viable options for patients with suspected metal hypersensitivity. Early clinical results of ceramic-coated metal seem to be positive, but more clinical data are needed to determine whether ceramic-coated metals are a cost-effective alternative. Key Study Points • Both anatomic articular geometry and ACL function (via retention or substitution) may be required to restore normal knee kinematics following TKA. • Anatomic joint line restoration via the appropriate positioning of standard implants or implants with asymmetric thicknesses may facilitate more normal soft-tissue function. • All-polyethylene tibial components have been shown to have long-term clinical outcomes equivalent to those of metal-backed components. • OxZr and bulk ceramics are alternatives to CoCr that have excellent mid- to long-term survivorship and favorable clinical outcomes.

Annotated References 1. Noble PC, Gordon MJ, Weiss JM, Reddix RN, Conditt MA, Mathis KB: Does total knee replacement restore normal knee function? Clin Orthop Relat Res 2005;431: 157-165. Medline  DOI 2. Larsen B, Jacofsky MC, Jacofsky DJ: Quantitative, comparative assessment of gait between single-radius and multi-radius total knee arthroplasty designs. J Arthroplasty 2015;30(6):1062-1067. Medline  DOI This study compared gait analysis, electromyography, and patient-reported outcome measures in patients who underwent single-radius and multiradius TKA with those of healthy control patients. Decreased power absorption and increased knee extension were noted in the multiradius group, but no functional differences were detected in outcome measures. Level of evidence: II.

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3. Hinarejos P, Puig-Verdie L, Leal J, et al: No differences in functional results and quality of life after single-radius or multiradius TKA. Knee Surg Sports Traumatol Arthrosc 2015 [Epub ahead of print]. Medline  DOI This prospective study demonstrates no significant differences between single-radius and multiradius TKA groups at 1- or 5-year follow-up for Knee Society scores (knee, function, or total), Medical Outcomes Study 36-Item Short Form physical scores, postoperative ROM, or patient satisfaction. Level of evidence: II. 4. Liu S, Long H, Zhang Y, Ma B, Li Z: Meta-analysis of outcomes of a single-radius versus multi-radius femoral design in total knee arthroplasty. J Arthroplasty 2016;31(3): 646-654. Medline  DOI This meta-analysis incorporated data from 15 studies comparing single-radius and multiradius TKA designs. No differences were found between the groups in Knee Society scores, complications, knee flexion, isometric peak torque, and survivorship; however, decreased ROM was noted for single-radius knees. Level of evidence: II. 5. Cherian JJ, Kapadia BH, Banerjee S, Jauregui JJ, Issa K, Mont MA: Mechanical, anatomical, and kinematic axis in TKA: Concepts and practical applications. Curr Rev Musculoskelet Med 2014;7(2):89-95. Medline  DOI This review provides an overview of alignment strategies in TKA and discusses the implications for outcome. Level of evidence: V.

This randomized controlled trial compared joint line maintenance and outcomes between patients undergoing computer-assisted and conventional TKA. No significant difference in joint line maintenance was found between the techniques. However, TKAs with a depressed joint improved the least in functional scores. Level of evidence: I. 7. Delport H, Labey L, De Corte R, Innocenti B, Vander Sloten J, Bellemans J: Collateral ligament strains during knee joint laxity evaluation before and after TKA. Clin Biomech (Bristol, Avon) 2013;28(7):777-782. Medline  DOI This study compared medial collateral ligament and lateral collateral ligament strains in six cadaver knees before and after posterior-stabilized TKA. Strain was significantly different before and after TKA at some but not all points measured throughout the flexion arc. Level of evidence: V. 8. Gromov K, Korchi M, Thomsen MG, Husted H, Troelsen A: What is the optimal alignment of the tibial and femoral components in knee arthroplasty? Acta Orthop 2014;85(5):480-487. Medline  DOI An overview of alignment strategies in TKA is provided and implications on outcome are discussed. Level of evidence: III.

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10. Dossett HG, Estrada NA, Swartz GJ, LeFevre GW, Kwasman BG: A randomised controlled trial of kinematically and mechanically aligned total knee replacements: Twoyear clinical results. Bone Joint J 2014;96-B(7):907-913. Medline  DOI This randomized controlled trial compared the results of mechanically aligned versus kinematically aligned TKAs in 88 patients. Function, ROM, and pain improvement scores were superior among patients with kinematically aligned TKAs 2 years postoperatively. Level of evidence: I. 11. Dai Y, Scuderi GR, Bischoff JE, Bertin K, Tarabichi S, Rajgopal A: Anatomic tibial component design can increase tibial coverage and rotational alignment accuracy: A comparison of six contemporary designs. Knee Surg Sports Traumatol Arthrosc 2014;22(12):2911-2923. Medline  DOI This study examined 479 healthy tibiae in Asian and Caucasian patients. Compared with asymmetric and symmetric designs, the anatomic tibial tray design demonstrated better conformity and tibial coverage, and less downsizing to ensure rotational alignment. Level of evidence: III. 12. Stulberg SD, Goyal N: Which tibial tray design achieves maximum coverage and ideal rotation: Anatomic, symmetric, or asymmetric? An MRI-based study. J Arthroplasty 2015;30(10):1839-1841. Medline  DOI This MRI-based study of 100 knees evaluated three different tibial tray designs: anatomic, symmetric, and asymmetric. Equivalent coverage was observed across the three tibial tray designs; however, the anatomic tibial tray required less malrotation to maximize coverage. Level of evidence: III.

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6. Babazadeh S, Dowsey MM, Swan JD, Stoney JD, Choong PF: Joint line position correlates with function after primary total knee replacement: A randomised controlled trial comparing conventional and computer-assisted surgery. J Bone Joint Surg Br 2011;93(9):1223-1231. Medline  DOI

9. Matsuda S, Miura H, Nagamine R, Urabe K, Hirata G, Iwamoto Y: Effect of femoral and tibial component position on patellar tracking following total knee arthroplasty: 10-year follow-up of Miller-Galante I knees. Am J Knee Surg 2001;14(3):152-156. Medline

13. Clary C, Aram L, Deffenbaugh D, Heldreth M: Tibial base design and patient morphology affecting tibial coverage and rotational alignment after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2014;22(12): 3012-3018. Medline  DOI Tibial anthropometric measurements for 14,791 patients who underwent TKA were compared across four commercial tibial tray designs. All designs provided similar bone coverage. Rotating the tibial tray to maximize coverage did not significantly increase coverage but induced variability in tray alignment. Level of evidence: III. 14. Voigt J, Mosier M: Cemented all-polyethylene and metal-backed polyethylene tibial components used for primary total knee arthroplasty: A systematic review of the literature and meta-analysis of randomized controlled trials involving 1798 primary total knee implants. J Bone Joint Surg Am 2011;93(19):1790-1798. Medline  DOI This systematic review and meta-analysis of 1,798 patients who underwent TKA from 12 studies reported no significant differences in revision or radiographic failure

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between all-polyethylene and metal-backed components at 2-, 10-, or 15-year follow-up. No functional difference was identified. Level of evidence: I. 15. Nouta KA, Verra WC, Pijls BG, Schoones JW, Nelissen RG: All-polyethylene tibial components are equal to metal-backed components: Systematic review and metaregression. Clin Orthop Relat Res 2012;470(12):35493559. Medline  DOI This meta-analysis included 26 articles with more than 12,500 patients who underwent TKA and reported no differences in revision rates, functional outcomes, ROM, or alignment between the all-polyethylene and metal-back components, except for higher component migration in the metal-backed group. Level of evidence: I. 16. Mohan V, Inacio MC, Namba RS, Sheth D, Paxton EW: Monoblock all-polyethylene tibial components have a lower risk of early revision than metal-backed modular components. Acta Orthop 2013;84(6):530-536. Medline  DOI This study examined a large community-based total joint registry of 27,657 patients undergoing TKA with the same implant (91.7% were metal-backed; 8.3% were all-­polyethylene). The revision rate for all etiologies was lower for the all-polyethylene group than for the metal-­ backed group (1.95% versus 2.17%; P < 0.001). Level of evidence: III.

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17. Gudnason A, Hailer NP, W-Dahl A, Sundberg M, Robertsson O: All-Polyethylene Versus Metal-Backed Tibial Components-An Analysis of 27,733 Cruciate-Retaining Total Knee Replacements from the Swedish Knee Arthroplasty Register. J Bone Joint Surg Am 2014;96(12): 994-999. Medline  DOI This study examined patients who underwent TKA with metal-backed (57.7%) or all-polyethylene (42.3%) tibial components at a median follow-up of 4.5 years. All-polyethylene tibial components had superior 10-year survival, reduced risk of revision for any reason, and reduced risk of revision because of infection. Level of evidence: III. 18. Gioe TJ, Sinner P, Mehle S, Ma W, Killeen KK: Excellent survival of all-polyethylene tibial components in a community joint registry. Clin Orthop Relat Res 2007;464(464):88-92. Medline 19. Pomeroy DL, Schaper LA, Badenhausen WE, et al: Results of all-polyethylene tibial components as a cost-saving technique. Clin Orthop Relat Res 2000;380:140-143. Medline  DOI 20. Verra WC, van den Boom LG, Jacobs W, Clement DJ, Wymenga AA, Nelissen RG: Retention versus sacrifice of the posterior cruciate ligament in total knee arthroplasty for treating osteoarthritis. Cochrane Database Syst Rev 2013;10(10):CD004803. Medline This study used systematic review and meta-analysis of randomized and quasirandomized controlled trials to compare PCL retention and sacrifice in TKA. No clinically relevant differences in ROM, pain, clinical, or radiologic

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outcomes were noted between PCL retention and sacrifice. Level of evidence: II. 21. Iwamoto K, Tomita T, Yamazaki T, et al.: Comparison of in vivo kinematics of total knee arthroplasty between cruciate retaining and condylar stabilized insert. Orthopaedic Proceedings 2014;96-B(suppl 11):167. The in vivo kinematics of Triathlon cruciate-retaining implants (10 knees) and cruciate-stabilizing insert implants (10 knees) were evaluated during deep knee bending. Cruciate-stabilizing knees showed significantly greater medial anterior translation, indicating that the increased anterior lip could not fully control anterior sliding. Level of evidence: III. 22. Kim TW, Lee SM, Seong SC, Lee S, Jang J, Lee MC: Different intraoperative kinematics with comparable clinical outcomes of ultracongruent and posterior stabilized mobile-bearing total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2015 [Epub ahead of print]. Medline  DOI In this randomized controlled study, the intraoperative kinematics and clinical outcomes (3-year follow-up) were compared for mobile ultracongruent and mobile posterior-stabilized TKAs. Ultracongruent knees showed greater paradoxical anterior translation, but no difference in clinical outcomes was detected between groups. Level of evidence: II. 23. Lützner J, Firmbach FP, Lützner C, Dexel J, Kirschner S: Similar stability and range of motion between cruciate-retaining and cruciate-substituting ultracongruent insert total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2015;23(6):1638-1643. Medline  DOI Intraoperative stability and ROM were compared before and after TKA with cruciate-retaining or ultracongruent inserts. Stability and ROM were similar between the two insert types, and both showed significant increases in postoperative anterior-posterior translation in flexion. Level of evidence: II. 24. Massin P, Boyer P, Sabourin M: Less femorotibial rotation and AP translation in deep-dished total knee arthroplasty. An intraoperative kinematic study using navigation. Knee Surg Sports Traumatol Arthrosc 2012;20(9):1714-1719. Medline  DOI This study tested the intraoperative kinematics of 10 knees replaced with hypercongruent inserts. Significant changes in kinematics relative to the nonsurgical condition were detected, including abnormal posterior location at full extension, reduced rollback, and persistent forward rolling on the medial side. Level of evidence: II. 25. Argenson JN, Boisgard S, Parratte S, et al; French Society of Orthopedic and Traumatologic Surgery (SOFCOT): Survival analysis of total knee arthroplasty at a minimum 10 years’ follow-up: A multicenter French nationwide study including 846 cases. Orthop Traumatol Surg Res 2013;99(4):385-390. Medline  DOI

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This retrospective study assessed 826 TKA patients. Most TKAs sacrificed the PCL (65% posterior-stabilized versus 35% ultracongruent): 10-year TKA survivorship was 92% independent of the design and level of mechanical stress. Revision was mainly performed for infection or loosening. Level of evidence: IV. 26. Varadarajan KM, Zumbrunn T, Rubash HE, Malchau H, Muratoglu OK, Li G: Reverse engineering nature to design biomimetic total knee implants. J Knee Surg 2015;28(5):363-369. Medline  DOI This report described a novel design process to create biomimetic tibial articular surfaces directly from the in vivo kinematics of normal knees. Geometric comparisons and kinematic simulations are used to demonstrate the role of articular geometry in the restoration of normal kinematics. Level of evidence: V. 27. Li JS, Hosseini A, Cancre L, Ryan N, Rubash HE, Li G: Kinematic characteristics of the tibiofemoral joint during a step-up activity. Gait Posture 2013;38(4): 712-716. Medline  DOI The in vivo kinematics of 21 healthy subjects were evaluated using biplanar fluoroscopy during step-up activity. Medial-pivot motion was not observed during this activity. Mean (±SD) medial and lateral tibiofemoral contact points moved almost equally with knee extension (13.5 ± 3.2 and 10.7 ± 5.0 mm, respectively). Level of evidence: IV. 28. Johal P, Williams A, Wragg P, Hunt D, Gedroyc W: Tibio-femoral movement in the living knee. A study of weight bearing and non-weight bearing knee kinematics using ‘interventional’ MRI. J Biomech 2005;38(2): 269-276. Medline  DOI

33. Varadarajan KM, Zumbrunn T, Rubash HE, Malchau H, Li G, Muratoglu OK: Cruciate retaining implant with biomimetic articular surface to reproduce activity dependent kinematics of the normal knee. J Arthroplasty 2015;30(12):2149-53. Medline  DOI In this study, simulated kinematics of a cruciate-retaining implant with an anatomic (biomimetic) articular surface were compared with those of contemporary cruciate-­ retaining implants. The biomimetic implant more closely mimicked normal kinematic patterns than contemporary cruciate-retaining implants across different simulated activities. Level of evidence: V. 34. van Duren BH, Pandit H, Price M, et al: Bicruciate substituting total knee replacement: How effective are the added kinematic constraints in vivo? Knee Surg Sports Traumatol Arthrosc 2012;20(10):2002-2010. Medline  DOI The in vivo kinematics of 10 Journey bicruciate-substituting knees were compared with that of 20 normal knees. The Journey knees showed no paradoxical anterior movement, and the patellar tendon angle and patellar flexion profiles were more normal than other TKA designs. Level of evidence: III. 35. Victor J, Mueller JK, Komistek RD, Sharma A, Nadaud MC, Bellemans J: In vivo kinematics after a cruciatesubstituting TKA. Clin Orthop Relat Res 2010;468(3): 807-814. Medline  DOI 36. Zumbrunn T, Varadarajan KM, Rubash HE, Malchau H, Li G, Muratoglu OK: Regaining native knee kinematics following joint arthroplasty: A novel biomimetic design with ACL and PCL preservation. J Arthroplasty 2015;30(12):2143-2148. Medline  DOI

In vivo kinematics during pivoting, kneeling, lunge, and step-up/-down activities were studied using fluoroscopy in 14 patients who underwent TKA. Observed kinematics were similar in pattern but smaller in magnitude compared with normal knees. No paradoxical anterior motion was observed for any activity. Level of evidence: IV.

Computer simulations were used to compare the kinematics of a bicruciate-retaining TKA with an anatomic (biomimetic) articular surface with that of contemporary bicruciate-retaining and cruciate-retaining implants. Restoration of native knee geometry together with ACL preservation provided kinematic patterns closest to normal knees. Level of evidence: V.

30. Barnes CL, Blaha JD, DeBoer D, Stemniski P, Obert R, Carroll M: Assessment of a medial pivot total knee arthroplasty design in a cadaveric knee extension test model. J Arthroplasty 2012;27(8):1460-1468. Medline  DOI

37. Stiehl JB, Komistek RD, Cloutier JM, Dennis DA: The cruciate ligaments in total knee arthroplasty: A kinematic analysis of 2 total knee arthroplasties. J Arthroplasty 2000;15(5):545-550. Medline  DOI

Knee extension kinematics of medial-pivot TKAs were evaluated in cadaver knees. Tibiofemoral rotation and translation were similar in direction but reduced in magnitude for prosthetic knees compared with intact knees. Quadriceps force was not statistically different between prosthetic and intact knees. Level of evidence: V.

38. Johnson AJ, Howell SM, Costa CR, Mont MA: The ACL in the arthritic knee: How often is it present and can preoperative tests predict its presence? Clin Orthop Relat Res 2013;471(1):181-188. Medline  DOI

31. Koo S, Andriacchi TP: The knee joint center of rotation is predominantly on the lateral side during normal walking. J Biomech 2008;41(6):1269-1273. Medline  DOI

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29. Shimmin A, Martinez-Martos S, Owens J, Iorgulescu AD, Banks S: Fluoroscopic motion study confirming the stability of a medial pivot design total knee arthroplasty. Knee 2015;22(6):522-526. Medline  DOI

32. Lew WD, Lewis JL: The effect of knee-prosthesis geometry on cruciate ligament mechanics during flexion. J Bone Joint Surg Am 1982;64(5):734-739. Medline

In this study, ACL integrity was evaluated using the Lachman test in 200 patients who underwent TKA and in 100 patients using MRI. The ACL was intact in 78% of knees. The Lachman test alone had poor sensitivity; when combined with MRI, sensitivity of 93.3% and specificity of 99% were attained. Level of evidence: IV.

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39. Varadarajan KM, Zumbrunn T, Duffy MP, Rubash HE, Malchau H, Muratoglu OK: Poster No. 1885. Is retention of native ACL the only option for addressing abnormal anteroposterior kinematics of cruciate retaining TKA? In: Proceedings of the 62nd Annual Meeting of the Orthopaedic Research Society; March 5-8, 2016; Orlando, FL. Rosemont, IL, Orthopaedic Research Society, p 146. This study compared the simulated kinematics of an ASCR design with an ACL-sacrificing cruciate-retaining implant and ACL-retaining bicruciate-retaining implant. The results showed that the ACL substitution mechanism could successfully replicate the kinematic function of the ACL across different activities. Level of evidence: V. 40. Christen B, Neukamp M, Aghayev E: Consecutive series of 226 journey bicruciate substituting total knee replacements: Early complication and revision rates. BMC Musculoskelet Disord 2014;15:395. Medline  DOI Complication and revision rates in 226 Journey bicruciate-­ substituting TKA patients were studied (average implantation time, 3.5 years): 33 complications in 25 patients (14.6%) required minor or major revision. Caution was advised for less-experienced surgeons using this implant. Level of evidence: IV. 41. Arnout N, Vandenneucker H, Bellemans J: Posterior dislocation in total knee replacement: A price for deep flexion? Knee Surg Sports Traumatol Arthrosc 2011;19(6): 911-913. Medline  DOI

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In this study, four cases of posterior dislocation were described for patients with Journey bicruciate-substituting TKAs. The authors concluded that specific design features contributed to higher-than-expected dislocation rates. Level of evidence: IV. 42. Halewood C, Risebury M, Thomas NP, Amis AA: Kinematic behaviour and soft tissue management in guided motion total knee replacement. Knee Surg Sports Traumatol Arthrosc 2014;22(12):3074-3082. Medline  DOI Ligament length changes and tibiofemoral kinematics were evaluated in cadaver knees with three TKAs: Journey ­bicruciate-substituting, Journey II bicruciate-substituting, and Genesis II posterior-stabilized implants. The results supported the hypothesis that increased internal rotation and rollback in the original Journey bicruciate-­substituting system caused excessive soft-tissue tightening. Level of evidence: V. 43. Iida T, Minoda Y, Kadoya Y, et al: Mid-term clinical results of alumina medial pivot total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc 2012;20(8): 1514-1519. Medline  DOI The clinical results of 107 alumina medial-pivot TKAs were evaluated at a mean follow-up of 5 years. Significant improvements in Knee Society scores and postoperative ROM were noted. No knees exhibited aseptic loosening, osteolysis, or ceramic fractures. Survivorship was 98.6%. Level of evidence: IV.

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44. Nakamura S, Kobayashi M, Ito H, Nakamura K, Ueo T, Nakamura T: The Bi-Surface total knee arthroplasty: Minimum 10-year follow-up study. Knee 2010;17(4): 274-278. Medline  DOI 45. Bergschmidt P, Bader R, Ganzer D, et al: Prospective multi-centre study on a composite ceramic femoral component in total knee arthroplasty: Five-year clinical and radiological outcomes. Knee 2015;22(3):186-191. Medline  DOI Clinical and radiologic assessments were performed for 107 TKA patients with Multigen-Plus ceramic knees. Nonprogressive radiolucent lines were observed around the femoral component in four cases. Neither implant migration nor loosening was registered. Kaplan-Meier survivorship was 96.0% at 60 months. Level of evidence: IV. 46. Kluess D, Bergschmidt P, Mueller I, Mittelmeier W, Bader R: Influence of the distal femoral resection angle on the principal stresses in ceramic total knee components. Knee 2012;19(6):846-850. Medline  DOI This study used finite-element analysis to evaluate the influence of distal femur preparation on stresses within a ceramic femoral component. A deviation of 3° from the intended resection angle was shown to cause critical stresses, thus underscoring the importance of precise femoral resection. Level of evidence: V. 47. van Hove RP, Sierevelt IN, van Royen BJ, Nolte PA: Titanium-nitride coating of orthopaedic implants: A review of the literature. Biomed Res Int 2015;2015:485975. Medline  DOI This review discussed preclinical studies and clinical outcomes of TiN-coated implants. Although TiN coating was reported to have positive effects on biocompatibility and tribology, several cases of third-body wear were reported as a result of delamination and cohesive failure of the TiN coating. Level of evidence: V. 48. Affatato S, Spinelli M, Lopomo N, Grupp TM, Marcacci M, Toni A: Can the method of fixation influence the wear behaviour of ZrN coated unicompartmental mobile knee prostheses? Clin Biomech (Bristol, Avon) 2011;26(2):152158. Medline  DOI Knee simulator wear tests were conducted for a multilayer ZrN-coated mobile-bearing unicompartmental prosthesis. No loss of coating was observed following 3 million test cycles. Both new and tested components showed macropores and micropores, which were likely created by the coating process. Level of evidence: V. 49. Thienpont E: Titanium niobium nitride knee implants are not inferior to chrome cobalt components for primary total knee arthroplasty. Arch Orthop Trauma Surg 2015;135(12):1749-1754. Medline  DOI This retrospective study compared 40 TiNbN-coated TKAs with 80 conventional CoCr implants at a mean follow-up of 2 years. No differences in clinical, radiologic, or patient-reported outcomes were observed. No

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patients had been revised as of the last evaluation. Level of evidence: IV. 50. Mohammed A, Metcalfe A, Woodnutt D: Medium-term outcome of titanium nitride, mobile bearing total knee replacement. Acta Orthop Belg 2014;80(2):269-275. Medline This retrospective study examined the outcomes of 305 TiN-coated mobile-bearing TKAs. The 10-year survival with revision for any reason as the end point was 95.1%, and with revision for aseptic loosening as the end point was 99.1%. Level of evidence: IV. 51. Schüttler KF, Efe T, Heyse TJ, Haas SB: Oxidized zirconium bearing surfaces in total knee arthroplasty: Lessons learned. J Knee Surg 2015;28(5):376-381. Medline  DOI

This study reported on 40 consecutive patients who underwent bilateral cruciate-retaining TKA with an OxZr femoral component in one knee and CoCr component in the contralateral knee. No significant differences were reported in clinical, subjective, or radiographic outcomes at 5-year follow-up. Level of evidence: I. 53. Hofer JK, Ezzet KA: A minimum 5-year follow-up of an oxidized zirconium femoral prosthesis used for total knee arthroplasty. Knee 2014;21(1):168-171. Medline  DOI This study retrospectively reviewed 109 TKAs in 82 patients at minimum follow-up of 5 years. Survivorship free of bearing-related complications was 100%. No revisions were reported for loosening, osteolysis, implant failure, or deep infection. Level of evidence: IV.

This review of both in vitro and in vivo studies evaluated the performance of oxidized zirconium TKAs and the results from retrieval analyses. Level of evidence: V.

54. Innocenti M, Matassi F, Carulli C, Nistri L, Civinini R: Oxidized zirconium femoral component for TKA: A follow-up note of a previous report at a minimum of 10 years. Knee 2014;21(4):858-861. Medline  DOI

52. Hui C, Salmon L, Maeno S, Roe J, Walsh W, Pinczewski L: Five-year comparison of oxidized zirconium and cobalt-chromium femoral components in total knee arthroplasty: A randomized controlled trial. J Bone Joint Surg Am 2011;93(7):624-630. Medline  DOI

This prospective study reported 10-year outcomes for 94 patients with oxidized zirconium TKA. Survivorship was 97.8% at 10 years. Two knees were revised for aseptic loosening of the femoral component. No other major complications were observed clinically or radiologically. Level of evidence: IV.

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Chapter 11

Special Considerations in Primary Total Knee Arthroplasty Andrew B. Old, MD  William J. Long, MD, FRCSC  W. Norman Scott, MD, FACS

Abstract The number of total knee arthroplasties is projected to increase annually. Two patient groups, young patients (age 55 years and younger) and patients with obesity, will contribute most to that number. Both groups have unique surgical challenges and should be given special consideration before total knee arthroplasty is performed. Concerns regarding early failure secondary to aseptic loosening, infection, and implant positioning should prompt the surgeon to counsel patients preoperatively and maximize outcomes in the operating room by means of thorough planning. Proper implant positioning and fixation are essential for a successful outcome.

Introduction Total knee arthroplasty (TKA) is routinely performed across the United States in a range of hospital settings, including large academic institutions, small community hospitals, and increasingly, outpatient surgicenters. A large percentage of the TKAs are performed by practitioners who are not fellowship trained in adult reconstruction. Despite being commonplace, TKA in certain patient cohorts requires special consideration. Young patients and obese patients are susceptible to complications such as early aseptic loosening or infection. Technical tips are available to maximize results in these difficult patient cohorts.

Keywords: obesity; young patient; total knee arthroplasty; infection; aseptic loosening; malalignment

Dr. Long or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Pacira Pharmaceuticals; serves as a paid consultant to Biomet, Ortho Development, and Pacira Pharmaceuticals; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. Dr. Scott is a previous royalty-bearing designer for Zimmer; serves as a paid consultant to the Board of Trustees for Ortho Development; and serves as the President of the International Congress for Joint Reconstruction. Neither Dr. Old nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

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TKA in Young Patients The rate of TKAs is expected to increase dramatically, and a higher percentage of these patients will be categorized as young, usually defined as age 55 years or younger. By 2030, primary TKAs in the United States are projected to increase by 637% and revisions by 601% compared with numbers reported in 2005.1 Similar trends have been observed in the United Kingdom and New Zealand, suggesting that these are international phenomena.2,3 With these staggering projections and the financial burden to the healthcare system, the young patient undergoing TKA requires special consideration. Young patients generally will place higher physical demands on their implants. Although constant improvements have been made in prosthetics and implants overall, the same implants initially designed for low-demand, somewhat frail community ambulators are now expected to withstand the high demands of the younger patient. Expectations are much higher than simply pain relief and the renewed ability to walk on level ground, climb stairs, and perhaps engage in light activity. The original Knee Society scoring system assessed only the patient’s ability to walk and climb stairs and was later modified

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to accommodate patients’ expanded expectations.4 The young patient’s expectations now include strenuous activity and higher impact sports and recreation, and they are reflected in the updated Knee Society scoring system.5 Despite these higher expectations, young patients may report greater residual symptoms following TKA. A national multicenter study6 assessed 661 young patients (mean age, 54 years) regarding residual symptoms and daily functional deficits. Although 89% of young patients were satisfied with their ability to perform activities of daily living, 33% reported pain, 41% reported stiffness, 33% reported swelling, and 38% and 31% reported difficulties getting in and out of a car and a chair, respectively. More than one-half of young patients reported difficulty navigating stairs. Given this outcome, the surgeon must manage patients’ expectations preoperatively and counsel them appropriately regarding the goals of care. Along with higher expectations and greater residual symptoms, the young patient also requires the implant to last longer to avoid revision arthroplasty. Currently, the likelihood is much greater that the implant will not outlive the recipient,7 so the primary TKA should last for as long as possible. At 10-year follow-up, researchers found that patients younger than 47 years at the time of their index TKA were twice as likely to require a revision as they were to die. Patients approximately 58 years old at the time of their index TKA had a 50:50 likelihood of requiring revision versus dying. Patients approximately 62 years or older at the time of their index TKA were more likely to die within 10 years before requiring revision.7 Given the increased demands on the prosthesis, the young patient population would be expected to experience loosening of their implants over time; however, prostheses seem to be failing even earlier than would be expected.8 Generally, osteolysis resulting from polyethylene wear particles would cause loosening, but evidence suggests that TKAs performed in young patients are failing before obvious polyethylene wear occurs. One study retrospectively compared a cohort of patients younger than 50 years with a matched cohort of patients age 60 to 70 years9 and determined the etiology of failure for the index procedure and any subsequent revisions that were performed. The mean time from the initial TKA to the first revision in the younger cohort was 36 months (range, 1 to 210 months) compared with 59 months (range, 1 to 230 months) in the older cohort. Essentially, TKA failure occurred in a shorter time frame in younger patients. Infection Infection has been reported as the second major cause of early revision TKA in the young patient population (after aseptic loosening),9 comprising 23% of failures.

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A 2014 study10 evaluated the increased revision rate for TKA secondary to infection in young patients and reported that patients younger than 50 years underwent revision TKA because of infection at approximately twice the rate of patients age 65 years or older (1.36% versus 0.73% incidence). This result excludes patients with inflammatory arthritis, who have a higher rate of infection. The study also noted male sex and African American race as independent risk factors for infection. Congestive heart failure, obesity, psychosis, and diabetes were all comorbidities that independently increased the risk of periprosthetic infections. Reasons for increased rates of infection in young patients can be a result of patients in this group having a higher percentage of posttraumatic arthritis or more surgical attempts at joint preservation (such as multiple injections, arthroscopies, or meniscal allografts).7 Aseptic Loosening The literature has shown that young patients also have a higher rate of aseptic loosening. A 2014 study reported that revision for aseptic mechanical failure was 1.15% but increased to 3.49% for those younger than 50 years and decreased to 0.75% for those 65 years or older.9 Aseptic loosening has been reported to account for 27% of early failures. Early aseptic revisions have been performed for loosening, continued pain, poor range of motion, and instability.7 Given the poor performance of revision procedures in the young patient cohort, the surgeon must clearly delineate the diagnosis and the reason a revision will resolve the patient’s problem. Persistent pain without a clear cause is a poor indication for revision TKA and will likely result in patient dissatisfaction after the procedure. Success in the Young Cohort Some investigators have documented good success rates and longevity with their younger patient cohorts.11,12 The findings of an ongoing longitudinal outcome study showed that overall survivorship without revision for any cause after 30 years was 70.1%, and the survivorship for tibial or femoral loosening was 82.5%.11 The mean Hospital for Special Surgery score improved from 57.9 points preoperatively to 85.3 points at 30-year follow-up. The mean Knee Society score was 87.4, and the mean functional Knee Society score was 62.1. The mean Tegner and Lysholm activity score improved from 1.5 points preoperatively to 3.0 points postoperatively. A literature review that included 908 TKAs in 671 patients12 reported that implant survivorship was between 90.6% and 99.0% during the first decade in patients younger than 55 years. This decreased to between 85.0%

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Chapter 11: Special Considerations in Primary Total Knee Arthroplasty

and 96.5% during the second decade. Patients showed functional improvement, with the mean Knee Society clinical and functional scores improving by 47 and 37 points, respectively. TKA in Patients With Obesity

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Body Mass Index Classification Classification

Body Mass Index (kg/m2)

Underweight

or = 20 degrees. J Arthroplasty 2004;19: 862-866. Medline  DOI 2. Bellemans J: Multiple needle puncturing: Balancing the varus knee. Orthopedics 2011;34(9):e510-e512. Medline This article describes a soft-tissue balancing technique, where the MCL is safely punctured until correct ligament balance was achieved by using a 19-gauge needle. In 62 of 64 cases, a progressive correction of medial tightness was achieved. 3. Meftah M, Blum YC, Raja D, Ranawat AS, Ranawat CS: Correcting fixed varus deformity with flexion contracture during total knee arthroplasty: the “inside-out” technique: AAOS exhibit selection. J Bone Joint Surg Am 2012;94:e66. Medline  DOI Correction of varus deformities was demonstrated by using a posteromedial capsulotomy at the level of the tibial cut and incising the superficial MCL with the pie-crusting technique. 4. Bellemans J, Vandenneucker H, Van Lauwe J, Victor J: A new surgical technique for medial collateral ligament balancing: Multiple needle puncturing. J Arthroplasty 2010;25:1151-1156. Medline  DOI This article presented a new technique for soft-tissue balancing of the medial compartment of the knee. Multiple punctures in the MCL are made by using a 19-gauge needle to progressively stretch the MCL until correct ligament balance is achieved. Correction was achieved in 34 of 35 cases with this technique. 5. Kubiak P, Archibeck MJ, White RE Jr: Cruciate-retaining total knee arthroplasty in patients with at least fifteen degrees of coronal plane deformity. J Arthroplasty 2008;23:366-370. Medline  DOI 6. Rajgopal A, Dahiya V, Vasdev A, Kochhar H, Tyagi V: Long-term results of total knee arthroplasty for valgus knees: Soft-tissue release technique and implant selection. J Orthop Surg (Hong Kong) 2011;19:60-63. Medline This article reported the long-term results of valgus knees after TKA. Patients had significantly improved Hospital for Special Surgery knee scores and ROM (P < 0.001 for both). 7. Miyasaka KC, Ranawat CS, Mullaji A: 10- to 20-year followup of total knee arthroplasty for valgus deformities. Clin Orthop Relat Res 1997;345:29-37. Medline 8. Stamos VB, Bono JV: Management of the stiff total knee arthroplasty, in Bono JV, Scott RD, eds: Revision Total Knee Arthroplasty . New York, Springer, 2005. DOI 9. Ebert JR, Munsie C, Joss B: Guidelines for the early restoration of active knee flexion after total knee arthroplasty: Implications for rehabilitation and early intervention. Arch Phys Med Rehabil 2014;95:1135-1140. Medline  DOI

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Chapter 16: The Difficult Primary Total Knee Arthroplasty

The association between active knee flexion at initial and final outpatient visits after TKA was investigated. Active knee flexion of 80° at 1 to 2 weeks postoperatively was significantly correlated with active flexion of 100° at 7 weeks. 10. Ritter MA, Harty LD, Davis KE, Meding JB, Berend ME: Predicting range of motion after total knee arthroplasty: Clustering, log-linear regression, and regression tree analysis. J Bone Joint Surg Am 2003;85-A:1278-1285. Medline 11. Ritter MA, Lutgring JD, Davis KE, Berend ME, Pierson JL, Meneghini RM: The role of flexion contracture on outcomes in primary total knee arthroplasty. J Arthroplasty 2007;22:1092-1096. Medline  DOI 12. Abdel MP, Della Valle CJ: The surgical approach for revision total knee arthroplasty. Bone Joint J 2016;98-B(suppl A):113-115. Medline  DOI This report highlights several surgical approaches during revision TKA, including quadriceps snip, tibial tubercle osteotomy, and in some rare cases, a V-Y quadricepsplasty. 13. Della Valle CJ, Berger RA, Rosenberg AG: Surgical exposures in revision total knee arthroplasty. Clin Orthop Relat Res 2006;446:59-68. Medline  DOI 14. Barrack RL, Smith P, Munn B, Engh G, Rorabeck C: The Ranawat Award: Comparison of surgical approaches in total knee arthroplasty. Clin Orthop Relat Res 1998;356: 16-21. Medline  DOI

16. Langen S, Gaber S, Zdravkovic V, Giesinger K, Jost B, Behrend H: Lateral subvastus approach with tibial tubercle osteotomy for primary total knee arthroplasty: Clinical outcome and complications compared to medial parapatellar approach. Eur J Orthop Surg Traumatol 2016;26:215-222. Medline  DOI This article evaluated the clinical outcomes of 580 patients with primary TKA with the lateral subvastus approach combined with a TTO with a standard medial parapatellar approach. Outcomes between the two cohorts were similar; however, the lateral subvastus approach was encouraged for use in difficult TKAs.

19. Scuderi G, Scharf SC, Meltzer LP, Scott WN: The relationship of lateral releases to patella viability in total knee arthroplasty. J Arthroplasty 1987;2:209-214. Medline  DOI 20. Engh GA, Ammeen DJ: Bone loss with revision total knee arthroplasty: Defect classification and alternatives for reconstruction. Instr Course Lect 1999;48:167-175. Medline 21. Shen C, Lichstein PM, Austin MS, Sharkey PF, Parvizi J: Revision knee arthroplasty for bone loss: Choosing the right degree of constraint. J Arthroplasty 2014;29(1): 127-131. Medline  DOI A prospective review of more than 470 revision TKAs of knees determined that increased constraint was effective in setting of increased bone deficiency. 22. Daines BK, Dennis DA: Management of bone defects in revision total knee arthroplasty. Instr Course Lect 2013;62:341-348. Medline This report describes how the use of stem extension in cases of bone deficits is helpful in enhancing fixation and lessening stresses to weakened condylar bone. 23. Ritter MA, Harty LD: Medial screws and cement: A possible mechanical augmentation in total knee arthroplasty. J Arthroplasty 2004;19:587-589. Medline  DOI 24. Brand MG, Daley RJ, Ewald FC, Scott RD: Tibial tray augmentation with modular metal wedges for tibial bone stock deficiency. Clin Orthop Relat Res 1989;248:71-79. Medline 25. Pagnano MW, Trousdale RT, Rand JA: Tibial wedge augmentation for bone deficiency in total knee arthroplasty. A followup study. Clin Orthop Relat Res 1995;321:151-155. Medline 26. Backstein D, Safir O, Gross A: Management of bone loss: Structural grafts in revision total knee arthroplasty. Clin Orthop Relat Res 2006;446:104-112. Medline  DOI 27. Bauman RD, Lewallen DG, Hanssen AD: Limitations of structural allograft in revision total knee arthroplasty. Clin Orthop Relat Res 2009;467:818-824. Medline  DOI

17. Nikolopoulos DD, Polyzois I, Apostolopoulos AP, Rossas C, Moutsios-Rentzos A, Michos IV: Total knee arthroplasty in severe valgus knee deformity: Comparison of a standard medial parapatellar approach combined with tibial tubercle osteotomy. Knee Surg Sports Traumatol Arthrosc 2011;19:1834-1842. Medline  DOI

28. Clatworthy MG, Ballance J, Brick GW, Chandler HP, Gross AE: The use of structural allograft for uncontained defects in revision total knee arthroplasty. A minimum five-year review. J Bone Joint Surg Am 2001;83-A: 404-411. Medline

This study compared the standard medial parapatellar approach with a lateral parapatellar approach combined with a TTO for TKA in 44 valgus knees. The groups showed no significant difference in International Knee Society System Score.

29. Engh GA, Ammeen DJ: Use of structural allograft in revision total knee arthroplasty in knees with severe tibial bone loss. J Bone Joint Surg Am 2007;89:2640-2647. Medline  DOI

18. Smith PN, Parker DA, Gelinas J, Rorabeck CH, Bourne RB: Radiographic changes in the patella following

30. Lachiewicz PF, Bolognesi MP, Henderson RA, Soileau ES, Vail TP: Can tantalum cones provide fixation in

© 2017 American Academy of Orthopaedic Surgeons

2: Knee

15. Meek RM, Greidanus NV, McGraw RW, Masri BA: The extensile rectus snip exposure in revision of total knee arthroplasty. J Bone Joint Surg Br 2003;85:1120-1122. Medline  DOI

quadriceps turndown for revision total knee arthroplasty. J Arthroplasty 2004;19:714-719. Medline  DOI

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complex revision knee arthroplasty? Clin Orthop Relat Res 2012;470:199-204. Medline  DOI This retrospective review of 27 patients who underwent revision TKA with 33 tantalum cones demonstrated that metaphyseal fixation with tantalum cones can be achieved. 31. Mabry TM, Hanssen AD: The role of stems and augments for bone loss in revision knee arthroplasty. J Arthroplasty 2007;22(suppl 1):56-60. Medline  DOI 32. Patel JV, Masonis JL, Guerin J, Bourne RB, Rorabeck CH: The fate of augments to treat type-2 bone defects in revision knee arthroplasty. J Bone Joint Surg Br 2004;86: 195-199. Medline  DOI 33. Meneghini RM, Lewallen DG, Hanssen AD: Use of porous tantalum metaphyseal cones for severe tibial bone loss during revision total knee replacement. J Bone Joint Surg Am 2008;90:78-84. Medline  DOI 34. Kamath AF, Lewallen DG, Hanssen AD: Porous tantalum metaphyseal cones for severe tibial bone loss in revision knee arthroplasty: A five to nine-year follow-up. J Bone Joint Surg Am 2015;97:216-223. Medline  DOI Porous tantalum tibial cones can serve as an option for tibial bone loss. At 5- to 9-year follow-up, porous tantalum tibial cones had durable clinical results and radiographic fixation. 35. Nandi S, Aghazadeh M, Talmo C, Robbins C, Bono J: Perioperative clopidogrel and postoperative events after hip and knee arthroplasties. Clin Orthop Relat Res 2012;470:1436-1441. Medline  DOI 2: Knee

The authors found that withholding clopidogrel for at least 5 days before hip or knee arthroplasty may lower the rate of bleeding events, and that an American Society of Anesthesiologists score of 4, advanced age, and revision surgery may be risk factors for bleeding events. 36. Singh JA, Jensen MR, Harmsen WS, Gabriel SE, Lewallen DG: Cardiac and thromboembolic complications and mortality in patients undergoing total hip and total knee arthroplasty. Ann Rheum Dis 2011;70:2082-2088. Medline  DOI This study reported on 90-day complications following TKA or THA. They noted that older age, higher comorbidity, higher American Society of Anesthesiologists classification, and history of cardiac/thromboembolic disease were associated with increased risk of complications. 37. Belmont PJ Jr, Goodman GP, Waterman BR, Bader JO, Schoenfeld AJ: Thirty-day postoperative complications and mortality following total knee arthroplasty: Incidence and risk factors among a national sample of 15,321 patients. J Bone Joint Surg Am 2014;96:20-26. Medline  DOI Diabetes and age increased the risk of mortality after primary unilateral TKA. Predictive factors for postoperative complications included an American Society of Anesthesiologists classification of 3 or greater, increased age, increased surgical time, and greater body mass.

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38. Mokdad AH, Ford ES, Bowman BA, et al: Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. JAMA 2003;289:76-79. Medline  DOI 39. Kurtz S, Ong K, Lau E, Mowat F, Halpern M: Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am 2007;89:780-785. Medline  DOI 40. Samson AJ, Mercer GE, Campbell DG: Total knee replacement in the morbidly obese: A literature review. ANZ J Surg 2010;80:595-599. Medline  DOI This review article evaluated the outcomes of TKA in morbidly obese patients. It was concluded that these patients should be advised to lose weight before surgery or to consider bariatric surgery. 41. D’Apuzzo MR, Novicoff WM, Browne JA: The John Insall Award: Morbid obesity independently impacts complications, mortality, and resource use after TKA. Clin Orthop Relat Res 2015;473:57-63. Medline  DOI Morbid obesity was associated with a higher risk of some in-hospital postoperative complications and mortality, even after matching for comorbid medical conditions linked to obesity. 42. Amin AK, Clayton RA, Patton JT, Gaston M, Cook RE, Brenkel IJ: Total knee replacement in morbidly obese patients. Results of a prospective, matched study. J Bone Joint Surg Br 2006;88:1321-1326. Medline  DOI 43. Naziri Q, Issa K, Malkani AL, Bonutti PM, Harwin SF, Mont MA: Bariatric orthopaedics: Total knee arthroplasty in super-obese patients (BMI > 50 kg/m2). Survivorship and complications. Clin Orthop Relat Res 2013;471:35233530. Medline  DOI The authors found that complications were more frequent and functional outcomes were significantly lower in superobese patients. No differences in aseptic implant survivorship were noted between superobese patients and those with lower BMI. 4 4. Han HS, Kang SB: Relations between long-term glycemic control and postoperative wound and infectious complications after total knee arthroplasty in type 2 diabetics. Clin Orthop Surg 2013;5:118-123. Medline  DOI The authors found that poorly controlled hyperglycemia before surgery may increase the incidence of wound complications among diabetic patients after TKA. 45. Einhorn TA, Boskey AL, Gundberg CM, Vigorita VJ, Devlin VJ, Beyer MM: The mineral and mechanical properties of bone in chronic experimental diabetes. J Orthop Res 1988;6:317-323. Medline  DOI 46. Singh JA, Lewallen DG: Diabetes: A risk factor for poor functional outcome after total knee arthroplasty. PLoS One 2013;8(11):e78991. Medline  DOI The authors found that diabetes, as well as its severity, was independently associated with poorer functional outcome.

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Chapter 16: The Difficult Primary Total Knee Arthroplasty

47. Wang S, Zhao Y: Diabetes mellitus and the incidence of deep vein thrombosis after total knee arthroplasty: A retrospective study. J Arthroplasty 2013;28:595-597. Medline  DOI This retrospective study examined the risk of DVT in patients with diabetes mellitus undergoing TKA within 14 days. Patients with diabetes had a 2.76-fold greater risk of DVT compared with those without diabetes mellitus. 48. Hwang JS, Kim SJ, Bamne AB, Na YG, Kim TK: Do glycemic markers predict occurrence of complications after total knee arthroplasty in patients with diabetes? Clin Orthop Relat Res 2015;473:1726-1731. Medline  DOI A positive correlation was found among the various available glycemic markers among patients with diabetes mellitus undergoing TKA, and patients undergoing surgery with hemoglobin A1c of 8 or higher and/or fasting blood glucose of 200 mg/dL or greater were associated with superficial surgical site infection. 49. Meding JB, Reddleman K, Keating ME, et al: Total knee replacement in patients with diabetes mellitus. Clin Orthop Relat Res 2003;416:208-216. Medline  DOI 50. Robertson F, Geddes J, Ridley D, McLeod G, Cheng K: Patients with Type 2 diabetes mellitus have a worse functional outcome post knee arthroplasty: A matched cohort study. Knee 2012;19:286-289. Medline  DOI This study demonstrated that diabetes mellitus leads to worse outcomes after knee arthroplasty, although no significant difference was demonstrable in KSSs at 5 years (P = 0.35), suggesting patient satisfaction remains high during this period.

52. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III): Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 2002;106:3143-3421. Medline 53. Zmistowski B, Dizdarevic I, Jacovides CL, Radcliff KE, Mraovic B, Parvizi J: Patients with uncontrolled components of metabolic syndrome have increased risk of complications following total joint arthroplasty. J Arthroplasty 2013;28:904-907. Medline  DOI The authors’ analysis confirmed independent associations between control of metabolic syndrome components as well as both length of stay and perioperative complications. 54. Mraovic B, Hipszer BR, Epstein RH, et al: Metabolic syndrome increases risk for pulmonary embolism after hip and knee arthroplasty. Croat Med J 2013;54:355-361. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

55. Gandhi R, Razak F, Tso P, Davey JR, Mahomed NN: Metabolic syndrome and the incidence of symptomatic deep vein thrombosis following total knee arthroplasty. J Rheumatol 2009;36:2298-2301. Medline  DOI 56. Lee JK, Choi CH: Total knee arthroplasty in rheumatoid arthritis. Knee Surg Relat Res 2012;24(1):1-6. Medline  DOI The authors of this study suggested that patients with rheumatoid arthritis have additional risk of late complications, which must be considered to improve the results of TKA in these patients. 57. Danoff JR, Moss G, Liabaud B, Geller JA: Total knee arthroplasty considerations in rheumatoid arthritis. Autoimmune Dis 2013;2013:185340. Medline The authors of this study suggested that providers share an understanding of the special considerations in this unique population of patients to ensure success in the immediate perioperative and postoperative periods, including specific modalities to maximize success. 58. Neva MH, Häkkinen A, Mäkinen H, Hannonen P, Kauppi M, Sokka T: High prevalence of asymptomatic cervical spine subluxation in patients with rheumatoid arthritis waiting for orthopaedic surgery. Ann Rheum Dis 2006;65:884-888. Medline  DOI 59. Ravi B, Escott B, Shah PS, et al: A systematic review and meta-analysis comparing complications following total joint arthroplasty for rheumatoid arthritis versus for osteoarthritis. Arthritis Rheum 2012;64:3839-3849. Medline  DOI

2: Knee

51. Isomaa B, Henricsson M, Almgren P, Tuomi T, Taskinen MR, Groop L: The metabolic syndrome influences the risk of chronic complications in patients with type II diabetes. Diabetologia 2001;44:1148-1154. Medline  DOI

The authors of this study found that patients with metabolic syndrome are at increased risk of pulmonary embolism after TJA. The increasing number of metabolic syndrome components significantly increased the incidence of pulmonary embolism.

The authors of this study found that their literature review and meta-analysis indicate that, compared with patients with osteoarthritis, patients with rheumatoid arthritis are at higher risk of dislocation and higher risk of infection after TKA. 60. Schnaser EA, Browne JA, Padgett DE, Figgie MP, D’Apuzzo MR: Perioperative complications in patients with inflammatory arthropathy undergoing total knee arthroplasty. J Arthroplasty 2015;30(suppl):76-80. Medline  DOI The authors of this study found that inflammatory subtypes had a higher rate of orthopaedic complications postoperatively compared with patients with osteoarthritis. Ankylosing spondylitis had the highest mortality rate as well as medical complication rate among the subtypes. 61. Jauregui JJ, Kapadia BH, Dixit A, et al: Thirty-day complications in rheumatoid patients following total knee arthroplasty. Clin Rheumatol 2016;35:595-600. Medline  DOI The authors of this study suggested that patients who have rheumatoid arthritis with end-stage knee arthritis may benefit from TKA; these patients should be preoperatively optimized to minimize complication risks.

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62. Archibeck MJ, Berger RA, Barden RM, et al: Posterior cruciate ligament-retaining total knee arthroplasty in patients with rheumatoid arthritis. J Bone Joint Surg Am 2001;83-A:1231-1236. Medline 63. Feng B, Weng X, Lin J, Jin J, Wang W, Qiu G: Long-term follow-up of cemented fixed-bearing total knee arthroplasty in a Chinese population: A survival analysis of more than 10 years. J Arthroplasty 2013;28(10):1701-1706. Medline  DOI The authors of this study found that Chinese patients with rheumatoid arthritis had lower long-term survivorship compared with patients who had osteoarthritis. Younger patients had better Hospital for Special Surgery scores. 64. Behrens EM, Beukelman T, Gallo L, et al: Evaluation of the presentation of systemic onset juvenile rheumatoid arthritis: Data from the Pennsylvania Systemic Onset Juvenile Arthritis Registry (PASOJAR). J Rheumatol 2008;35:343-348. Medline 65. Abdel MP, Figgie MP: Surgical management of the juvenile idiopathic arthritis patient with multiple joint involvement. Orthop Clin North Am 2014;45:435-442. Medline  DOI

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The authors of this study discussed TJAs in patients who have juvenile idiopathic arthritis. Focus is placed on overall epidemiology, coordination of care, and medical and surgical managements of these patients undergoing THA and TKA.

71. Mertelsmann-Voss C, Lyman S, Pan TJ, Goodman S, Figgie MP, Mandl LA: Arthroplasty rates are increased among US patients with systemic lupus erythematosus: 19912005. J Rheumatol 2014;41:867-874. Medline  DOI The authors of this study suggested that patients with SLE are now living long enough for osteoarthritis to develop and are healthy enough to undergo elective surgery. 72. Issa K, Pierce TP, Scillia AJ, et al: Midterm outcomes following total knee arthroplasty in lupus patients. J Arthroplasty 2016;31:655-657. Medline  DOI The authors of this study suggest excellent clinical and patient-reported outcomes of TKA in patients with or without SLE. Prospective studies are necessary to evaluate these outcomes at longer follow-up. 73. Shah UH, Mandl LA, Mertelsmann-Voss C, et al: Systemic lupus erythematosus is not a risk factor for poor outcomes after total hip and total knee arthroplasty. Lupus 2015;24:900-908. Medline  DOI

66. Parvizi J, Lajam CM, Trousdale RT, Shaughnessy WJ, Cabanela ME: Total knee arthroplasty in young patients with juvenile rheumatoid arthritis. J Bone Joint Surg Am 2003;85-A:1090-1094. Medline

The authors of this study found that although patients with SLE have more comorbidities than those with osteoarthritis, and those with SLE who have had THA have worse preoperative pain and function compared with osteoarthritis controls, SLE was not an independent risk factor for poor short-term pain or function after either hip or knee arthroplasty.

67. Heyse TJ, Ries MD, Bellemans J, et al: Total knee arthroplasty in patients with juvenile idiopathic arthritis. Clin Orthop Relat Res 2014;472(1):147-154. Medline  DOI

74. Troyer J, Levine BR: Proximal tibia reconstruction with a porous tantalum cone in a patient with Charcot arthropathy. Orthopedics 2009;32:358. Medline  DOI

The authors of this study showed that patients with juvenile rheumatoid arthritis typically have lower TKA survivorship rates than patients with osteoarthritis or rheumatoid arthritis. Functional limitations also are quite common in this population.

75. Fullerton BD, Browngoehl LA: Total knee arthroplasty in a patient with bilateral Charcot knees. Arch Phys Med Rehabil 1997;78:780-782. Medline  DOI

68. Thomas A, Rojer D, Imrie S, Goodman SB: Cemented total knee arthroplasty in patients with juvenile rheumatoid arthritis. Clin Orthop Relat Res 2005;433:140-146. Medline  DOI 69. Malviya A, Foster HE, Avery P, Weir DJ, Deehan DJ: Long term outcome following knee replacement in patients with juvenile idiopathic arthritis. Knee 2010;17:340-344. Medline  DOI This study retrospectively analyzed the long-term outcomes of 34 TKAs in 20 patients with juvenile idiopathic arthritis. At median follow-up of 16 years, various function and satisfaction scores were improved. At 20 years, survivorship was 58.5%. 70. Mukherjee S, Culliford D, Arden N, Edwards C: What is the risk of having a total hip or knee replacement for patients with lupus? Lupus 2015;24:198-202. Medline  DOI

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The authors of this study found that patients with lupus who underwent TKA or THA were younger than their peers without lupus. In addition, they appeared to have a significantly increased risk of TKA, but the increased risk of THA did not remain after adjustment for alcohol consumption and steroid use.

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76. Sugitani K, Arai Y, Takamiya H, Minami G, Higuchi T, Kubo T: Total knee arthroplasty for neuropathic joint disease after severe bone destruction eroded the tibial tuberosity. Orthopedics 2012;35:e1108-e1111. Medline  DOI The authors of this study described a patient who underwent TKA for neuropathic joint disease secondary to diabetes mellitus after severe bone destruction eroded the tibial tuberosity. 77. Parvizi J, Marrs J, Morrey BF: Total knee arthroplasty for neuropathic (Charcot) joints. Clin Orthop Relat Res 2003;416:145-150. Medline  DOI 78. Long WJ, Scuderi GR: Porous tantalum cones for large metaphyseal tibial defects in revision total knee arthroplasty: A minimum 2-year follow-up. J Arthroplasty 2009;24:1086-1092. Medline  DOI 79. Kim YH, Kim JS, Oh SW: Total knee arthroplasty in neuropathic arthropathy. J Bone Joint Surg Br 2002;84: 216-219. Medline  DOI © 2017 American Academy of Orthopaedic Surgeons

Chapter 17

Management of Extra-Articular Deformities in Knee Arthroplasty Abbas Naqvi, MD  Jaydev B. Mistry, MD  Randa K. Elmallah, MD  Morad Chughtai, MD  Michael A. Mont, MD

Abstract The success of total knee arthroplasty depends on adequate restoration of the lower extremity mechanical axis. However, the presence of extra-articular deformity can substantially complicate the attainment of this goal. Therefore, it is important to understand the various etiologies of extra-articular deformity, evaluation and diagnosis, the critical principles and approaches to deformity correction, outcomes, and new treatments for extra-articular deformities.

Keywords: extra-articular; deformity; varus; valgus; correction

mechanical axis, appropriate soft-tissue stabilization, and the establishment of adequate flexion and extension gaps.1-3 However, achieving these goals can be complicated by the presence of femoral or tibial extra-articular deformities, which can be the result of malunion, congenital or metabolic bone disease, prior osteotomy, tumor, or Paget disease. The presence of such deformities can render conventional TKA instrumentation ineffective. Therefore, adequate preoperative patient evaluation and identification of these deformities is critical to proper surgical planning and success. It is important to understand the etiology and cause of extra-articular knee deformities, evaluation and diagnosis, principles of treatment, and the use of new techniques to aid in the surgical correction of extra-articular knee deformities. 2: Knee

Etiologies of Extra-Articular Knee Deformities Introduction The long-term success of total knee arthroplasty (TKA) depends on accurate restoration of the lower extremity Dr. Mont or an immediate family member has received royalties from MicroPort and Stryker, serves as a paid consultant to DJ Orthopaedics, Johnson & Johnson, Merz, OrthoSensor, Pacira, Sage Products, Stryker, TissueGene, and US Medical Innovations; has received research or institutional support from DJ Orthopaedics, Johnson & Johnson, the National Institutes of Health (NIAMS & NICHD), Ongoing Care Solutions, OrthoSensor, Stryker, and Tissue Gene; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Naqvi, Dr. Mistry, Dr. Elmallah, and Dr. Chughtai.

© 2017 American Academy of Orthopaedic Surgeons

The etiologies for extra-articular deformities of the femur and/or tibia range from congenital conditions to malunion of a previous fracture. Adequate patient history and physical examination are critical to identifying such deformities and their etiologies in the preoperative setting. However, although numerous etiologies can affect the femur or tibia, the subsequent deformities are usually similar and, as such, are managed in a similar manner. Fracture Malunion One of the most common etiologies of extra-articular deformity is prior femoral or tibial fracture. Distal femoral fractures can occur in young patients (younger than 60 years) secondary to high-energy trauma and in the elderly secondary to falls. In addition, arthritis can develop subsequent to such injury as a result of poor alignment or direct intra-articular insult. This can be the underlying cause of arthritis in up to 7.2% of patients undergoing TKA.4,5 Patients with a history of distal femoral fracture are at risk for poor outcomes following TKA because of a combination of factors, including altered joint mechanics

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and the presence of hardware.5 As with distal femoral fractures, patients with a history of proximal tibial fractures are at increased risk of the development of arthritis, with rates as high as 44%.6 Furthermore, this patient population is at increased risk of postoperative complications including ankyloses, infection, and patellar subluxation following TKA. Knowledge of previous distal femoral or proximal tibial fractures is critical for both surgical planning and avoiding postoperative complications.

2: Knee

Congenital or Metabolic Bone Disease Congenital conditions, such as osteogenesis imperfecta or Blount disease, as well as metabolic diseases such as hereditary hypophosphatemia or hyperparathyroidism, also can result in substantial extra-articular deformity. Osteogenesis imperfecta is a genetic condition that affects the formation of bone and is characterized by the defective formation of type 1 collagen.7 There are multiple subtypes of osteogenesis imperfecta that range in severity from perinatal death and severe skeletal deformities to asymptomatic individuals predisposed to fractures. In patients who have osteogenesis imperfecta, metaphyseal flaring, which exhibits a “popcorn-like” appearance, can develop. In addition, bowing and thinning of the lower extremities can develop. The poor bone quality and frequent fractures in these patients may necessitate placement of intramedullary rods and may further complicate TKA.8 Blount disease has been linked to obesity and typically affects the posteromedial aspect of the tibial growth plate, resulting in bowing of the lower extremity.9 Although the tibial physis is more commonly affected, the late-onset variant of Blount disease can result in distal femoral varus deformity. Metabolic states such as hypophosphatemia and hyperparathyroidism primarily affect the quality of the bone by shifting the balance between osteogenesis and osteolysis in favor of osteolysis, which results in poor bone stock that may be more susceptible to implant loosening and subsequent failure.10 In addition, the presence of such conditions may compromise tendon integrity and increase the risk for tendon rupture that could complicate postoperative recovery after TKA. Prior High Tibial or Distal Femoral Osteotomy High tibial osteotomy (HTO) and distal femoral osteotomy (DFO) are used to alleviate symptoms and delay time to joint arthroplasty.11 These procedures are typically reserved for young patients and those with unicompartmental osteoarthritis with varus or valgus deformity. However, an overcorrected HTO or DFO can result in a varus or valgus deformity that can further complicate TKA. An analysis of 39 consecutive bilateral TKAs performed in patients with previous HTO found

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no significant difference in outcomes between TKAs that had or had not undergone HTO.12 The study noted a higher incidence of valgus alignment and patella infera in the HTO cohort. Therefore, the relationship between HTO and TKA outcomes requires further investigation. Nevertheless, orthopaedic surgeons should be aware of previous HTO because of the potential adhesions in the surgical field as well as changes in joint alignment. The surgical techniques to treat TKA after HTO or DFO are not specifically discussed in this chapter, but several descriptions have been published.12-14 Tumor Tumors violating the structural integrity of the femur or tibia can result in extra-articular deformity affecting the knee. Bone quality and prosthesis stability can be further complicated by factors such as the pharmacologic treatment and surgical removal of such tumors. Chemotherapeutic agents such as methotrexate, ifosfamide, and imatinib have been shown to adversely affect bone metabolism.15-17 Long-term use of methotrexate can result in osteopathy.17 Patients typically present with osteoporosis, severe bone pain, and bony changes resembling scurvy that are especially prominent in the lower extremities. Ifosfamide has been shown to adversely affect bone turnover and healing.18 Imatinib use may result in hypophosphatemia with secondary hyoparathryoidism;15 therefore, knowledge of previous tumor management as well as cessation, if possible, of chemotherapeutic agents before surgery may help improve postoperative outcomes in this high-risk patient population. Paget Disease of Bone Paget disease of bone is characterized by accelerated bone remodeling. Instead of the smooth, lamellar pattern that typically results, bone deposition occurs in a disorganized manner and can cause bone to become increasingly sclerotic and thickened, and subsequently replace normal bone marrow with fibrous and vascular tissue.19 This may result in pathologic stress fractures as well as bony deformity due to secondary osteoarthritis and altered biomechanical forces.20 Deformities in patients with Paget disease following TKA include distal femoral varus angulation and excessive bowing of the anterior tibia. Furthermore, increases in bone vascularity and marrow fibrosis present substantial risks for perioperative blood loss and component fixation, respectively.20,21 It is imperative that orthopaedic surgeons recognize these challenges during preoperative planning to provide optimal postoperative outcomes in these patients.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 17: Management of Extra-Articular Deformities in Knee Arthroplasty

Evaluation and Diagnosis Key Points of History and Physical Examination A detailed history and thorough physical examination are necessary to identify and evaluate extra-articular deformities. Patient history should include identification of any congenital or metabolic diseases of the bone, as well as any history of trauma to the lower extremity. In addition, any conditions such as rheumatoid arthritis or drugs that affect bone quality such as corticosteroids should be identified. Furthermore, prior surgeries, incisions, and placement of previous implants should be noted. The physical examination should begin with visual inspection of both the femur and the tibia for any gross deformity. The knee should be palpated for any tenderness and range of motion should be assessed. Varus-valgus stress should be applied in full extension, midextension, and 90° of flexion to assess for any ligamentous ­laxity. In addition, patient gait should be assessed for any abnormalities.

© 2017 American Academy of Orthopaedic Surgeons

Figure 1

Illustration demonstrates the effect of distance on magnitude of knee joint deformity (green dot) as it progresses closer to the knee joint from A to B to C. (Red lines = anatomic axis proximal to deformity, blue lines = anatomic axis distal to deformity, black lines = planned osteotomies, dashed lines = mechanical axis.)

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Imaging Modalities Full-length long-leg weight-bearing AP and lateral radiographs of the lower extremity are critical to preoperative planning and should be obtained. Such imaging is ­especially necessary if the patient has a history of previous femoral or tibial fracture. In addition, CT can help identify rotational deformities. However, the advent of a “kneeling view” radiograph, an imaging technique that obtains a view that facilitates assessment of rotational deformity and alignment of the distal femur, can provide similar information given the time and expense associated with CT.22,23 MRI may be indicated if concern exists for ligamentous injury and helps plan for adequate soft-tissue balancing. The importance of the extra-articular deformity is determined by two criteria: the magnitude of the deformity and the distance of the deformity from the knee joint.24,25 The magnitude of the deformity can be calculated using full-length weight-bearing AP views, which is accomplished by drawing a line proximal to distal from the center of the femoral head to the center of the knee joint. Another line is drawn from proximal to distal from the center of the knee joint to the center of the ankle. Finally, the angle between the intersection of the two lines is calculated. In addition, the product of the femoral or tibial shaft angulation and the proportional distance from the hip or ankle to the knee can calculate the amount of deformity at the knee joint. If the patient presents with a knee deformity with an angulation of 15°, the proportional distance can be calculated via the division of the proximal femoral segment by the length of the femur.

This product of the proportional distance and the angulation of the deformity yields the contribution of the angulation to the knee deformity. It can be reasoned that deformities of greater magnitude, whether determined by greater angulation or proportional distance to the joint, contribute to an increased severity of deformities. Therefore, these relevant factors warrant special consideration during preoperative planning. Furthermore, the closer the deformity is to the knee joint, the greater effect it has on the joint24,25 (Figure 1). Deformities closer to the knee translate to greater alterations in the joint space angle and mechanics compared with those deformities farther away. Deformities closer to the hip or ankle have minimal effect on the knee joint itself. Treatment Principles and Options Standard Intra-articular Corrections Although TKA with simultaneous or staged osteotomy for deformity correction has resulted in anatomic alignment

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and adequate ligament stabilization, the potential also exists for substantial complications.25,26 Osteotomy may require additional incisions and introduces the potential for nonunion, arthrofibrosis, and greater risk of infection. 25-27 In addition, nonunion of the osteotomy can compromise joint alignment. 25 DFOs are technically demanding and display inferior results compared with a constrained prosthesis or proximal tibial osteotomy. 28,29 Proximal tibial osteotomies involve longer surgical time and result in decreased knee flexion and increased incidence of patellar subuxation.27 In addition, staged procedures can prolong rehabilitation time.25 An intra-articular approach can be used to manage extra-articular deformities and avoid the potential morbidity associated with performing an osteotomy. Satisfactory outcomes have been demonstrated in patients who underwent TKA with intra-articular resection and soft-tissue balancing in knees with average extra-articular varus deformities of 15.1° in the coronal plane and 8.1° in the sagittal plane.25 In patients undergoing this approach, the mechanical axis was corrected from 23° of varus preoperatively to 0.3° of varus postoperatively. The Knee Society Score improved from 22 to 92 points and function scores from 28 to 87 at final follow-up. In addition, the range of motion increased from 78° preoperatively to 104° at 38 months. This approach uses oblique bone cuts of the distal femur or proximal tibia to achieve normal anatomic alignment and eliminates the need for osteotomy. However, intra-articular resection may not be an option or may require ligament reconstruction if the resection jeopardizes insertion of the collateral ligaments or affects ligament balancing. Intra-articular management of a distal femoral deformity is more challenging than a proximal tibial deformity as a result of the instability that can occur during extension.24 Valgus femoral (Figure 2) and tibial (Figure 3) deformities require medial overresection, which should be performed with caution because medial collateral ligament laxity during extension can occur. Varus femoral (Figure 4) and tibial (Figure 5) deformities require lateral overresection. However, the tensor fascia lata and the extensor mechanism can compensate for any lateral collateral ligament laxity during extension secondary to lateral femoral overresection.

Figure 2

Illustration demonstrates valgus femoral deformity that requires medial overresection. A, Schematic of deformity. B, Preoperative planning for medial femoral overresection. C, Schematic after deformity correction. (Green dot = center of deformity, red lines = anatomic axis proximal to deformity, blue lines = anatomic axis distal to deformity, black lines and shaded area = planned osteotomies, dashed lines = mechanical axis, LDTA = lateral distal tibial angle, LPFA = lateral proximal femoral angle.)

resection can result in compromise of the collateral ligaments, which can be treated by using either a more constrained prosthesis or ligament reconstruction.31 However, the excellent healing potential of the collateral ligaments as well as the disadvantages of a more constrained device favor ligament reconstruction. In addition, severe femoral deformity may require hip adduction or abduction for proper gait even after adequate restoration of TKA With Simultaneous or Staged Osteotomy the knee axis.24,26 Such gait abnormalities can potentially Although studies have demonstrated the success of intra-­ predispose patients to accelerated degeneration of the hip articular resection in patients with as much as 15° of joint.26 Therefore, TKA performed with simultaneous deformity in the coronal plane, some concern still exists or staged osteotomy may be advantageous to achieve for patients with an extra-articular deformity at any level adequate mechanical joint balance and to avoid use of a of 10° or more in the coronal plane or 20° or more in constrained implant.22,26 the sagittal plane as a result of the extensive resection Preoperative planning is critical to the success of such required to achieve proper balance.22,25,26,30 Such extensive a simultaneous or staged procedure. The presence of

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Figure 3

previously placed hardware and the decision to perform the surgery in one stage instead of two substantially increases the complexity of the procedure.26 A lateral approach enables hardware removal, osteotomy, and internal fixation to be performed through the same incision. In addition, the use of a precontoured blade plate or a locked intramedullary nail has led to adequate stabilization and union of the osteotomy. Patients who underwent this approach demonstrated a mean postoperative knee score of 87 points and a function score of 81 points, and all patients achieved a limb alignment within 2° of normal. This approach demonstrates restoration of the mechanical axis and subsequent functional improvement, pain reduction, and stability.26,32,33 Another successful approach described extending the TKA incision to 8 to

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Figure 4

Illustration demonstrates varus femoral deformity that requires lateral overresection. A, Schematic of deformity. B, Preoperative planning for lateral femoral overresection. C, Schematic after deformity correction. (Green dot = center of deformity, red lines = anatomic axis proximal to deformity, blue lines = anatomic axis distal to deformity, black lines and shaded area = planned osteotomies, dashed lines = mechanical axis. LDTA = lateral distal tibial angle, LPFA = lateral proximal femoral angle.)

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Illustration demonstrates valgus tibial deformity that requires medial overresection. A, Schematic of deformity. B, Preoperative planning for medial tibial overresection. C, Schematic after deformity correction. (Green dot = center of deformity, red lines = anatomic axis proximal to deformity, blue lines = anatomic axis distal to deformity, black lines and shaded area = planned osteotomies, dashed lines = mechanical axis, LDTA = lateral distal tibial angle, LPFA = lateral proximal femoral angle.)

10 cm inferior to the tibial tubercle while simultaneously using another incision 6 cm superior to the patella and medial to quadriceps tendon in 71 TKAs.34 This approach offers the advantage of attaining adequate exposure without violating the quadriceps muscle, which could compromise recovery, and excellent exposure and complete union was achieved in all osteotomies. Highly Constrained TKA Increased implant constraint results in an increased ability to withstand forces about the knee.35 However, this translates to greater forces placed on the implant and bone-implant interface. Increased constraint can result in greater wear, loosening, and subsequent implant failure. Therefore, it is often advantageous to select an

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usually reserved for patients undergoing TKA following tumor resection.37 However, distal femoral replacements have been used in patients with poor bone stock, extreme ligamentous instability, and severe deformity.37,38 A study conducted on outcomes following salvage knee reconstruction using a rotating hinged device showed suboptimal outcomes.38 Although patients demonstrated a mean increase of 53 points in Knee Society pain score, 3 cases of infected prostheses, 4 cases of aseptic loosening, and 1 case of periprosthetic fracture were reported. In addition, the rate of implant survival was 79.6% at 1 year and 68.2% at 5 years. The authors of this study recommended that this approach should be reserved for patients who are elderly and sedentary.38 Although not ideal and certainly not a long-term solution, a constrained implant may offer the benefit of pain reduction as well as other satisfactory outcomes in a select group of patients who are not candidates for other approaches.

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Figure 5

Illustration demonstrates varus tibial deformity that requires lateral overresection. A, Schematic of deformity. B, Preoperative planning for lateral tibial overresection. C, Schematic after deformity correction. (Green dot = center of deformity, red lines = anatomic axis proximal to deformity, blue lines = anatomic axis distal to deformity, black lines and shaded area = planned osteotomies, dashed lines = mechanical axis, LDTA = lateral distal tibial angle, LPFA = lateral proximal femoral angle.)

implant that offers the least amount of constraint while still achieving restoration of the mechanical axis and patient function. Use of a highly constrained implant is typically reserved for the most severe cases of deformity resulting in instability that cannot be corrected via intra-articular resection or extra-articular osteotomy alone, and has demonstrated good results in the most severe cases of deformity.35,36 A study conducted on outcomes following primary and revision TKA for severe deformity using a condylar constrained prosthesis demonstrated a postoperative knee score of 86 points; 82% of patients were classified as having a good outcome or better following TKA at 5-year follow-up.36 Another constrained option includes distal femoral arthroplasty, which used a rotating hinged distal femoral prosthesis. This implant is

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Preoperative Templating and Intraoperative Measurement Because poor functional outcomes are associated with ligamentous compromise, preoperative deformity measurements and templating are necessary to assess the feasibility of an intra-articular approach. In addition, accurate intraoperative measurements are critical to the placement of cutting guides and precise bone cuts. Distortion of bony anatomy secondary to deformity can decrease the accuracy of an intramedullary guide. Therefore, an extramedullary guide used with localization of the femoral head can result in more accurate measurements and better subsequent coronal alignment.28 Extensive varus angulation of the femur can be corrected by performing lateral overresection of the distal femur before implantation of components (Figure 6). New Treatments Computer-Assisted Navigation The advent of computer-assisted navigation resulted in a more accurate alternative to the use of medullary guides. Unlike medullary guides, computer-assisted navigation systems can accurately measure the mechanical axis irrespective of bony landmarks that are susceptible to variation and human error.39 In addition, the presence of deformity further increases the inaccuracy of medullary guides. Computer-assisted navigation systems have consistently demonstrated more accurate and reliable implant placement in TKA compared with conventional techniques.39-43 These patients have shown substantial improvement in femoral alignment, femoral rotation, tibial alignment, tibial rotation, tibial posterior slope,

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Figure 6

Images obtained from a 65-year-old man demonstrate posttraumatic osteoarthritis of the left knee secondary to a distal femur fracture sustained when the patient was 24 years old. Physical examination findings included obvious varus deformity of the left knee, a 15° flexion contracture, and an antalgic gait. Bilateral AP long-leg weightbearing (A) lateral (B), and AP (C) radiographs demonstrate a total of 22° of varus angulation at the knee (18° varus deformity at the knee and 4° varus deformity at the tibia.) Lateral (D) and AP (E) views obtained following total knee arthroplasty with lateral femoral overresection demonstrate correction of the deformity to neutral.

Patient-Specific Instrumentation Patient-specific instrumentation is another viable option that may help restore anatomic alignment under conditions in which normal anatomic landmarks are no longer useful, such as extra-articular deformity. CT or MRI are used to construct positioning guides and cutting blocks specific to the patient’s altered anatomy with the ultimate goal of increasing the accuracy of the knee implant.46-48 This instrumentation relies on direct

© 2017 American Academy of Orthopaedic Surgeons

mechanical alignment similar to computer-assisted navigation. A retrospective multicenter analysis of patients with extra-articular deformity undergoing TKA with patient-specific instrumentation demonstrated promising results.46 A mean Knee Society function score increase from 44 to 92 points was reported. In addition, Knee Society pain scores increased from 38 to 91 points. Moreover, as with computer-assisted navigation, patient-specific instrumentation does not violate the medullary canal and may decrease the incidence of fat embolism.46 Therefore, the use of patient-specific instrumentation may be beneficial for TKA in patients with extra-articular deformity.46

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and femorotibial mismatch compared with patients who underwent TKA with a conventional jig-based technique. Studies conducted on patients with extra-articular deformities using computer navigation reported a significant increase in postoperative Knee Society Scores, function scores, and range of motion.1,39,44 One study assessed the outcomes following TKA performed with computer navigation in patients with femoral extra-articular deformities.39 Knee Society and functional scores improved from 62 to 92 and from 52 to 83, respectively; flexion range of motion increased from 4° to 74° preoperatively to 0.6° to 98.0° at final follow-up. Furthermore, the use of navigation systems has been associated with decreased blood loss and incidence of fat emboli because the medullary canal was avoided.39,40,45 Therefore, computer-assisted navigation may help surgeons substantially improve outcomes in patients with extra-articular deformity undergoing TKA.

Summary The decision on how to best approach TKA in patients with extra-articular deformity should be based on extensive patient history, physical examination, and thorough evaluation of the magnitude and proximity of the deformity to the knee joint. Obtaining long-leg weight-bearing radiographs with AP and lateral views are necessary to evaluate the deformity. Although numerous techniques are available for performing TKA in patients with extra-­ articular deformity, most patients can be treated using standard techniques that do not require osteotomy or ligament reconstruction. In addition, computer-assisted navigation may further help achieve adequate alignment in this challenging patient population.

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Key Study Points • Extra-articular deformity of the knee can be caused by fracture malunion, congenital or metabolic bone disease, prior history of osteotomy, presence of a tumor, or Paget disease. • Deformities closer to the knee joint are of greater magnitude than deformities further from the knee joint. This should be considered during preoperative planning. • Various treatment options are available, including intra-articular corrections, TKA, computer-assisted navigation, and patient-specific instrumentation. • Thorough evaluation and preoperative planning are necessary to achieve adequate alignment in this challenging patient population.

Annotated References 1. Mullaji A, Shetty GM: Computer-assisted total knee arthroplasty for arthritis with extra-articular deformity. J Arthroplasty 2009;24(8):1164-9.e1. Medline  DOI 2. Oswald MH, Jakob RP, Schneider E, Hoogewoud HM: Radiological analysis of normal axial alignment of femur and tibia in view of total knee arthroplasty. J Arthroplasty 1993;8(4):419-426. Medline  DOI 2: Knee

3. Wasielewski RC, Galante JO, Leighty RM, Natarajan RN, Rosenberg AG: Wear patterns on retrieved polyethylene tibial inserts and their relationship to technical considerations during total knee arthroplasty. Clin Orthop Relat Res 1994;299:31-43. Medline 4. Meena RC, Meena UK, Gupta GL, Gahlot N, Gaba S: Intramedullary nailing versus proximal plating in the management of closed extra-articular proximal tibial fracture: A randomized controlled trial. J Orthop Traumatol 2015;16(3):203-208. Medline  DOI This randomized prospective clinical trial compared minimally invasive proximal tibial plating to intramedullary nailing; rigid fixation was noted in the utilization of both implants. 5. Papadokostakis G, Papakostidis C, Dimitriou R, Giannoudis PV: The role and efficacy of retrograding nailing for the treatment of diaphyseal and distal femoral fractures: A systematic review of the literature. Injury 2005;36(7): 813-822. Medline  DOI 6. Weiss NG, Parvizi J, Trousdale RT, Bryce RD, Lewallen DG: Total knee arthroplasty in patients with a prior fracture of the tibial plateau. J Bone Joint Surg Am 2003; 85-A(2):218-221. Medline

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7. Steiner RD, Adsit J, Basel D: COL1A1/2-Related Osteogenesis Imperfecta, in Pagon RA, Adam MP, Ardinger HH, et al.: GeneReviews. Seattle, WA, 2013. Medline This review article discusses the diagnosis, clinical characteristics, differential diagnoses, as well as treatment of COL1A1/2-related osteogenesis imperfecta. 8. Luhmann SJ, Sheridan JJ, Capelli AM, Schoenecker PL: Management of lower-extremity deformities in osteogenesis imperfecta with extensible intramedullary rod technique: A 20-year experience. J Pediatr Orthop 1998;18(1):88-94. Medline  DOI 9. Sabharwal S: Blount disease: An update. Orthop Clin North Am 2015;46(1):37-47. Medline  DOI This review article highlights the recent advances in the diagnosis and surgical management of Blount disease. 10. Chalmers J, Irvine GB: Fractures of the femoral neck in elderly patients with hyperparathyroidism. Clin Orthop Relat Res 1988;229:125-130. Medline 11. Waterman BR, Hoffmann JD, Laughlin MD, et al: Success of High Tibial Osteotomy in the United States Military. Orthop J Sports Med 2015;3(3):2325967115574670. Medline  DOI This retrospective analysis of military service members undergoing HTO found that 72% of patients undergoing HTO returned to duty and did not require conversion to TKA. 12. Meding JB, Keating EM, Ritter MA, Faris PM: Total knee arthroplasty after high tibial osteotomy. A comparison study in patients who had bilateral total knee replacement. J Bone Joint Surg Am 2000;82(9):1252-1259. Medline 13. Shih LY, Sim FH, Pritchard DJ, Rock MG, Chao EY: Segmental total knee arthroplasty after distal femoral resection for tumor. Clin Orthop Relat Res 1993;292: 269-281. Medline 14. Zywiel MG, Kosashvili Y, Gross AE, Safir O, Lakstein D, Backstein D: 161–total knee arthroplasty after distal femoral varus osteotomy: Mid-term results of selectively stemmed posterior stabilised components. Orthopaedic Proceedings 2011;93-B(Supp IV):586. This analysis retrospectively reviewed 22 consecutive varus DFOs that were converted to TKA at a mean follow-up of 5 years. Posterior-stabilized implants were used in all TKAs. Varus DFO reliably reduces pain and improves knee function. 15. Berman E, Nicolaides M, Maki RG, et al: Altered bone and mineral metabolism in patients receiving imatinib mesylate. N Engl J Med 2006;354(19):2006-2013. Medline  DOI 16. Pfeilschifter J, Diel IJ: Osteoporosis due to cancer treatment: Pathogenesis and management. J Clin Oncol 2000;18(7):1570-1593. Medline

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17. Schwartz AM, Leonidas JC: Methotrexate osteopathy. Skeletal Radiol 1984;11(1):13-16. Medline  DOI 18. Matos MA, Tannuri U, Guarniero R: Effect of ifosfamide on bone healing. J Musculoskelet Neuronal Interact 2006;6(3):247-250. Medline 19. Langston AL, Ralston SH: Management of Paget’s disease of bone. Rheumatology (Oxford) 2004;43(8):955-959. Medline  DOI 20. Al-Rashid M, Ramkumar DB, Raskin K, Schwab J, Hornicek FJ, Lozano-Calderón SA: Paget disease of bone. Orthop Clin North Am 2015;46(4):577-585. Medline  DOI This review article discusses the history, pathophysiology, diagnosis, presentation, and medical and surgical management of Paget disease of bone. 21. Bolland MJ, Cundy T: Paget’s disease of bone: Clinical review and update. J Clin Pathol 2013;66(11):924-927. Medline  DOI

30. Papadopoulos EC, Parvizi J, Lai CH, Lewallen DG: Total knee arthroplasty following prior distal femoral fracture. Knee 2002;9(4):267-274. Medline  DOI 31. Leopold SS, McStay C, Klafeta K, Jacobs JJ, Berger RA, Rosenberg AG: Primary repair of intraoperative disruption of the medical collateral ligament during total knee arthroplasty. J Bone Joint Surg Am 2001;83-A(1):86-91. Medline 32. Wang JW, Hsu CC: Distal femoral varus osteotomy for osteoarthritis of the knee. Surgical technique. J Bone Joint Surg Am 2006;88(suppl 1 Pt 1):100-108. Medline 33. Mann J, Insall J, Scuderi G: Total knee arthroplasty in patients with associated extra-articular angular deformity. Orthop Trans 1997;21:59. 34. Whiteside LA, Ohl MD: Tibial tubercle osteotomy for exposure of the difficult total knee arthroplasty. Clin Orthop Relat Res 1990;260:6-9. Medline

This article reviews recent clinical findings of Paget disease of bone. In addition, the authors review clinical trials that have been demonstrated as highly effective for treatment.

35. Morgan H, Battista V, Leopold SS: Constraint in primary total knee arthroplasty. J Am Acad Orthop Surg 2005;13(8):515-524. Medline  DOI

22. Papagelopoulos PJ, Karachalios T, Themistocleous GS, Papadopoulos ECh, Savvidou OD, Rand JA: Total knee arthroplasty in patients with pre-existing fracture deformity. Orthopedics 2007;30(5):373-378. Medline

36. Hartford JM, Goodman SB, Schurman DJ, Knoblick G: Complex primary and revision total knee arthroplasty using the condylar constrained prosthesis: An average 5-year follow-up. J Arthroplasty 1998;13(4):380-387. Medline  DOI

23. Takai S, Yoshino N, Isshiki T, Hirasawa Y: Kneeling view: A new roentgenographic technique to assess rotational deformity and alignment of the distal femur. J Arthroplasty 2003;18(4):478-483. Medline  DOI

25. Wang JW, Wang CJ: Total knee arthroplasty for arthritis of the knee with extra-articular deformity. J Bone Joint Surg Am 2002;84-A(10):1769-1774. Medline 26. Lonner JH, Siliski JM, Lotke PA: Simultaneous femoral osteotomy and total knee arthroplasty for treatment of osteoarthritis associated with severe extra-articular deformity. J Bone Joint Surg Am 2000;82(3):342-348. Medline 27. Haddad FS, Bentley G: Total knee arthroplasty after high tibial osteotomy: A medium-term review. J Arthroplasty 2000;15(5):597-603. Medline  DOI 28. Nelson CL, Saleh KJ, Kassim RA, et al: Total knee arthroplasty after varus osteotomy of the distal part of the femur. J Bone Joint Surg Am 2003;85-A(6):1062-1065. Medline 29. Windsor RE, Insall JN, Vince KG: Technical considerations of total knee arthroplasty after proximal tibial osteotomy. J Bone Joint Surg Am 1988;70(4):547-555. Medline

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24. Wolff AM, Hungerford DS, Pepe CL: The effect of extraarticular varus and valgus deformity on total knee arthroplasty. Clin Orthop Relat Res 1991;271:35-51. Medline

37. Berend KR, Lombardi AV Jr: Distal femoral replacement in nontumor cases with severe bone loss and instability. Clin Orthop Relat Res 2009;467(2):485-492. Medline  DOI 38. Pour AE, Parvizi J, Slenker N, Purtill JJ, Sharkey PF: Rotating hinged total knee replacement: Use with caution. J Bone Joint Surg Am 2007;89(8):1735-1741. Medline  DOI 39. Bottros J, Klika AK, Lee HH, Polousky J, Barsoum WK: The use of navigation in total knee arthroplasty for patients with extra-articular deformity. J Arthroplasty 2008;23(1):74-78. Medline  DOI 40. Chauhan SK, Scott RG, Breidahl W, Beaver RJ: Computer-assisted knee arthroplasty versus a conventional jigbased technique. A randomised, prospective trial. J Bone Joint Surg Br 2004;86(3):372-377. Medline  DOI 41. Bäthis H, Perlick L, Lüring C, Kalteis T, Grifka J: [CTbased and CT-free navigation in knee prosthesis implantation. Results of a prospective study]. Unfallchirurg 2003;106(11):935-940. Medline 42. Bäthis H, Perlick L, Tingart M, Lüring C, Zurakowski D, Grifka J: Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. J Bone Joint Surg Br 2004;86(5):682-687. Medline

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43. Hernández-Vaquero D, Suarez-Vazquez A, Sandoval-Garcia MA, Noriega-Fernandez A: Computer assistance increases precision of component placement in total knee arthroplasty with articular deformity. Clin Orthop Relat Res 2010;468(5):1237-1241. Medline  DOI This prospective study compared the radiographic alignment in TKAs performed with and without computer-assisted navigation. The authors found more accurate placement of the femoral and tibial component in the group treated with computer-assisted navigation. 44. Catani F, Digennaro V, Ensini A, Leardini A, Giannini S: Navigation-assisted total knee arthroplasty in knees with osteoarthritis due to extra-articular deformity. Knee Surg Sports Traumatol Arthrosc 2012;20(3):546-551. Medline  DOI This prospective study assessed the outcomes of navigation-assisted TKA in patients with arthritis secondary to extra-articular deformity with a mean 3-year follow-up. More than 90% of patients had good or excellent results. 45. Kalairajah Y, Cossey AJ, Verrall GM, Ludbrook G, Spriggins AJ: Are systemic emboli reduced in computer-assisted knee surgery?: A prospective, randomised, clinical trial. J Bone Joint Surg Br 2006;88(2):198-202. Medline  DOI

This retrospective review of 10 patients with multiplanar deformities had knee components aligned using patient-specific instrumentation. Function, range of motion, and limb alignment demonstrated significant improvement at a mean follow-up of 3.4 years. 47. Nunley RM, Ellison BS, Zhu J, Ruh EL, Howell SM, Barrack RL: Do patient-specific guides improve coronal alignment in total knee arthroplasty? Clin Orthop Relat Res 2012;470(3):895-902. Medline  DOI This retrospective review assessed whether mean coronal alignment after TKA performed with conventional vs patient-specific instrumentation better restored the kinematic and mechanical axes and determined which group had more outliers. Both methods were effective at restoring the axes but had similar numbers of outliers. 48. Ng VY, DeClaire JH, Berend KR, Gulick BC, Lombardi AV Jr: Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA. Clin Orthop Relat Res 2012;470(1):99-107. Medline  DOI This retrospective review compared the effectiveness of patient-specific positioning guides with that of manual instrumentation to restore mechanical axis and neutral coronal alignment. Patient-specific guides were useful in achieving neutral mechanical axis.

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46. Thienpont E, Paternostre F, Pietsch M, Hafez M, Howell S: Total knee arthroplasty with patient-specific instruments improves function and restores limb alignment in patients

with extra-articular deformity. Knee 2013;20(6):407-411. Medline  DOI

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Chapter 18

Outcomes of Primary Total Knee Arthroplasty David C. Ayers, MD  Patricia D. Franklin, MD, MBA, MPH  Rajiv Gandhi, MS, MD, FRCSC  Christopher Kim, MD, MSc  Jeffrey Lange, MD  Nizar N. Mahomed, MD, MPH, ScD  Philip C. Noble, PhD

Abstract

Introduction Jeffrey Lange, MD; Patricia D. Franklin, MD, MBA, MPH; David C. Ayers, MD

Total knee arthroplasty (TKA) has proved to be a major success, with long-term survivorship rates exceeding 90% in most studies. It has also provided marked and consistent quality-of-life improvements for recipients. The parameters governing success rates in TKA, including TKA implant design, bearing surface material, fixation techniques, alignment strategies, and patient-related factors, have been studied extensively over the past few decades. In 2016, there is the benefit of decades of experience with multiple TKA strategies. Many clinical studies, and now multiple national registries, provide a large amount of high-quality data that can inform current strategies and drive future optimization of total TKA. Multiple tools exist to allow evaluation of the success of these surgeries. It is important to review the current landscape regarding

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Total knee arthroplasty can relieve arthritic pain and improve quality of life in patients with debilitating arthritis. Currently, long-term survivorship rates of total knee arthroplasties have been demonstrated through multiple clinical and registry-based studies. Studies comparing survivorship rates of various knee arthroplasty designs and systems have provided guidance for optimizing the results of surgery. Patient-reported outcome measures have historically been used in clinical research and have become increasingly prevalent in clinical practice. These instruments provide patient-centered benchmarks for measuring the success of total knee arthroplasties by comparing patient-­reported pain and function both before and after total knee arthroplasty, and by documenting improvement and effect on quality of life. Patient satisfaction has historically lagged behind the success of total knee arthroplasty in relieving pain and represents an area of continued focus for optimization.

Keywords: survivorship; scoring systems; patient satisfaction; patient-reported outcome measures

Dr. Ayers or an immediate family member serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons and the American Orthopaedic Association. Dr. Franklin or an immediate family member has received research or institutional support from Zimmer Biomet. Dr. Mahomed or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew and has stock or stock options held in Arthritis Innovation Corporation. Dr. Noble or an immediate family member has received royalties from Stryker, Springer, and Zimmer Biomet; serves as a paid consultant to Zimmer Biomet; has stock or stock options held in Joint View; has received research or institutional support from CeramTech, DJO, Smith & Nephew, and Zimmer Biomet; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from the Musculoskeletal Transplant Foundation and AMTI; and serves as a board member, owner, officer, or committee member of Advanced Technology in Orthopedics, Orthopedic Discovery, Cognoscenti, the International Society of Technology in Orthopaedics, and the Knee Society. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Gandhi, Dr. Kim, and Dr. Lange.

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Figure 1

Graph shows revision rates following primary total knee arthroplasty, stratified by age. (Reproduced with permission from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man: 12th Annual Report, 2015. Available at: http://www.njrcentre.org.uk/njrcentre/. Accessed July 6, 2016.)

objective and subjective outcomes following TKA, as well as some of the tools used to track outcomes. Survivorship Assessments Jeffrey Lange, MD; Patricia D. Franklin, MD, MBA, MPH; David C. Ayers, MD 2: Knee

Annual Registry Reports The increasing utilization of research registries has improved the ability to analyze outcomes following TKA. Currently, multiple national registries provide detailed information regarding longitudinal outcomes after TKA. The outcome measures collected in many registries encompass patient demographics, implant details, and patient-reported outcomes. The following paragraph summarizes some of the patient- and implant-specific data reported by two national total joint arthroplasty registries with long-term follow-up. Information regarding patient-reported outcomes is detailed subsequently in this chapter. The 2015 annual report of the Australian National Joint Arthroplasty Registry1 notes an overall range of between 2.6% and 11.2% cumulative revision rates at 10-year follow-up for all tracked primary TKA femoral and tibial implant combinations. A total of 43 component combinations with 350 or more procedures recorded per year were included in this analysis. Of the 43 combinations, 13 (30.2%) demonstrated revision rates less than 5% at 10 years. These 13 combinations included cruciate-­retaining and cruciate-sacrificing designs. When

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analyzed by primary diagnosis, findings for osteoarthritis and rheumatoid arthritis were similar at 10- and 14-year follow-up with 5% to 7% revision rates. For other inflammatory arthritis diagnoses, osteonecrosis, and other diagnoses, the revision rates were higher at 10 years. When comparing outcomes of cemented versus noncemented TKA at 14 years, rates of revision were higher for noncemented TKA. The 2015 British National Registry Report2 demonstrates an overall revision rate following primary TKA of 3.62% for cemented constructs, 4.91% for noncemented constructs, and 3.57% for hybrid constructs at 11-year follow-up. Revision rate is inversely correlated with increasing age (Figure 1). For patients younger than 55 years, the revision rate at 10 years was 12.08% for males and 11.05% for females. For patients age 75 years and older, the revision rate at 10 years was 2.22% for men and 1.94% for women. For cemented versus ­noncemented­/ hybrid constructs in patients younger than 55 years, the revision rates at 10 years were 9.03% and 9.87%, respectively, for males and 7.66% and 8.44%, ­respectively, for females. For cemented versus noncemented/hybrid constructs in patients 75 years and older, the revision rates at 10 years were 1.92% and 2.11%, respectively, for men and 1.64% and 2.07%, respectively, for women. Registries are also able to track which implant types have performed poorly compared to their counterparts; these analyses are important applications of registry data. However, the most accurate assessment of outcomes over time requires longitudinal monitoring. Furthermore, it is

© 2017 American Academy of Orthopaedic Surgeons

Chapter 18: Outcomes of Primary Total Knee Arthroplasty

Table 1

Ten-Year Survivorship Rates of TKA Designs

Implant

Mean Patient Age (yr)

Clinical Score (Knee/Function)

10-yr Overall Survivorship (95% confidence interval)

176/300

Natural Knee CR

65

–

95.1% (93.2-98.0)

Barrington et al

87/127

Nexgen PS

70

94/75 (KSS)

97% (94-100)

Schwartz et al

126/179

Nexgen PS

62.4

85.4 (HSS)

97.7% (96.3-99.0)

No. of Patientsa

Hoffman et al

Clinical Study Fixed-bearing TKAs

Nakamura et al

309/507

Bisurface PS

68.5

93.3/52.7 (KSS)

97.4% (95.8-99.0)

Moutet et al

80/117

Europ CR

73

88/80 (KSS)

97.8% (91.5-99.5)

Present series

846/942

Multiple PS+CR

71

83/74 (KSS)

92% (90-94)

Callaghan et al

82/114

LCS PS

70

90/75

100%

Buechel

309/309

LCS CR

71

–

97.4% (95-100)

Mobile-bearing TKAs

Vogt and Saarbach

59/101

LCS PS

70

78/66 (KSS)

95%

Metsovitis et al

326

Rotaglide UC

66.7

92.6/66.7 (KSS)

96% (93-98)

Meftah et al

106/138

LCS PS

69.2

94 (HSS)

98.3% (97.1-99.5)

Argenson et al

108/116

Nexgen Flex PS

69

94/88 (KSS)

98.3% (97.1-99.5)

Present series

846/942

Multiple PS+CR

71

83/74 (KSS)

92% (90-94)

CR = cruciate (posterior cruciate ligament) retention, HSS = Hospital for Special Surgery score, KSS = Knee Society score, PS = posterior-stabilized; TKA = total knee arthroplasty, UC = ultracongruent. a Data are the number of patients followed-up/total number of patients. Adapted from Argenson J-N, Boisgard S, Parratte S, et al; French Society of Orthopedic and Traumatologic Surgery (SOFCOT): Survival analysis of total knee arthroplasty at a minimum 10 years' follow-up: A multicenter French nationwide study including 846 cases. Orthop Traumatol Surg Res 2013;99(4):385-390.

Peer-Reviewed Studies Peer-reviewed clinical and registry-based studies continue to corroborate the high survivorship rates of TKAs. A recent multicenter nationwide study followed 846 TKA recipients for at least 10 years and reported an overall survivorship rate of 92%. When subcategorized by implant type, the range in survivorship was 90% to 95%, without any significant differences among implant types. These results were comparable to those of multiple contemporary single-center studies3 (Table 1). A study of 117 consecutive cruciate-sacrificing (CS) mobile-bearing TKAs at a mean follow-up of 10 years demonstrated a survivorship rate of 97.7%.4 A systematic review of studies analyzing outcomes after primary TKA using one device reported

© 2017 American Academy of Orthopaedic Surgeons

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important to note that summary results reported through national registries cannot be generalized to all patients. It is the combination of both clinical studies aimed at evaluating the results of TKA in specific patient populations and registry reports that can inform the management of specific patient populations.

survivorship based on 15 peer-reviewed studies comprising 4,025 TKAs in addition to 233,843 knee arthroplasties identified among five national joint arthroplasty registries.5 Based on peer-reviewed literature alone, survivorship was found to be 97% at 13 years postoperatively, and pooled registry data showed a 10-year survivorship rate of 95.7%.5 A comparison between data from Norway’s National Joint Arthroplasty Registry and Kaiser Permanente’s Total Joint Arthroplasty Registry (United States) reported survivorship at midterm follow-up of TKAs at 94.8% and 96.3%, respectively.6 A review of survivorship of TKAs across multiple national registries and clinical studies reported the overall survivorship rate to be 93.8% at 10 years.7 Thus, in studies spanning multiple follow-up intervals, implant types, and patient demographics, TKA has proven to exhibit high survivorship rates. Cruciate-Retaining Versus Cruciate-Sacrificing Designs Over the past decades, multiple studies have evaluated the relative efficacy of cruciate-retaining (CR) versus CS TKA

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implant designs. Most studies found similar survivorship and clinical outcomes. A systematic review of 17 randomized controlled trials comparing the results of CR and CS implants at short- to midterm follow-up showed no clinically relevant differences in outcomes after TKA with respect to range of motion, pain, and clinical and radiographic outcome measures.8 A recent meta-analysis of eight randomized controlled trials comparing the outcomes of CR and CS implants in 963 primary TKAs found no significant differences in survivorship or clinical outcomes, with the exception of a modest improvement in range of motion scores with CS constructs at short- to midterm follow-up.9 The clinical relevance of this statistically significant finding was not assessed. International registry data demonstrate similar survivorship rates between CR and CS TKAs. At 10 years postoperatively, the 2015 Australian National Joint Arthroplasty Annual Report1 notes revision rates of 5.2% (95% confidence interval [CI]: 5.1-5.3) and 6.3% (95% CI: 6.0-6.5) for CR and CS constructs, respectively. The 2015 British National Joint Registry Annual Report2 demonstrates a similar pattern, but separates its results by sex and age. At 10 years postoperatively, cumulative revision rates of fixed-bearing cemented CR versus CS constructs are as follows: 8.52% (95% CI: 7.43-9.77) and 10.34% (95% CI: 8.35-12.77) in males younger than 55 years; 6.94% (95% CI: 6.09-7.90) and 7.74% (95% CI: 6.36-9.39) in females younger than 55 years; 1.82% (95% CI: 1.60-2.06) and 2.07% (95% CI: 1.70-2.51) in men age 75 years and older; and 1.53% (95% CI: 1.36-1.71) and 1.82% (95% CI: 1.56-2.12) in women age 75 years and older.

at 2-year follow-up. These findings corroborate multiple earlier studies.12 No data are yet available to demonstrate reduced wear in mobile-bearing designs, as longer follow-­ up is needed. Registry data also reflect these relationships. The 2015 Australian registry report demonstrates a slightly lower revision rate in fixed bearing versus mobile bearing designs, which are of three types: rotating, sliding, and rotating-sliding.1 The revision rates reported at 10 years postoperatively are 5.1% (95% CI: 5.0-5.2) for fixed-­ bearing designs, 6.5% (95% CI: 6.3-6.7) for rotating designs, 7.4% (95% CI: 6.6-8.2) for rotating-sliding designs, and 6.6% (95% CI: 5.1-8.4) for sliding designs. The 2015 British registry report separates results by sex, age, and stability.2 At 10 years postoperatively, cumulative revision rates for fixed-bearing versus mobile-bearing designs show no significant differences: 8.52% (95% CI: 7.43-9.77) and 9.91% (95% CI: 7.22-13.52) for CR constructs in males younger than 55 years; 6.94% (95% CI: 6.09-7.90) and 10.16% (95% CI: 6.84-14.97) for CR constructs in females younger than 55 years; 10.34% (95% CI: 8.35-12.77) and 7.14% (95% CI: 4.96-10.21) for CS constructs in males younger than 55 years; and 7.74% (95% CI: 6.36-9.39) and 10.19% (95% CI: 6.0916.80) for CS constructs in females younger than 55 years, respectively.

2: Knee

Cemented Versus Noncemented Constructs Over the past few decades, many investigators have assessed the survivorship of noncemented and cemented primary TKAs. Conflicting reports exist. Reported survivorship rates have ranged from 85% to 98% and 76% to 99% at 10- to 20-years’ follow-up for cemented and noncemented Mobile-Bearing Versus Fixed-Bearing Designs constructs, respectively.13 These reports reflect varying levMobile-bearing TKA implant designs were developed els of evidence. A recent meta-­analysis of 15 randomized in an effort to reduce polyethylene wear by decreasing controlled trials or observational studies demonstrated the degree of constraint in the implant system. Multiple likelihood of revision that were 4.2 times greater after investigators have reported satisfactory results using these noncemented fixation (95% CI: 2.7-6.5).14 Follow-up for implants, with similar survivorship of mobile-­bearing studies included in this meta-analysis ranged from 2 to designs compared to fixed-bearing designs. A recent pro- 11 years. The 2015 Australian registry report1 notes a spective randomized trial evaluating rotating-­platform hazard ratio of 1.12 for revision of noncemented versus versus fixed-bearing designs, using a single implant type, cemented primary TKAs at 14-year follow-up (P < 0.001) in 444 patients with simultaneous bilateral TKA (mobile (Figure 2). This reflects an average revision rate of 8.2% bearing on one side, fixed bearing on the other) demon- (95% CI: 7.6-8.8) for noncemented constructs and 6.7% strated no significant differences in survivorship or radio- (95% CI: 6.4-7.0) for cemented constructs. When analyzed graphic outcomes at a minimum 10-year follow-­up (mean, by sex, the revision of noncemented versus cemented pri12.1 years).10 Another recent prospective randomized mary TKAs in females at 13-year follow-up was found to trial compared mobile-bearing to fixed-­bearing cruciate-­ have a hazard ratio of 1.21 (P < 0.001, 2014 data). The substituting primary TKAs (PFC Sigma PS) with and 2015 annual report of the British registry2 notes 11-year without patellar resurfacing;11 no single combination of revision rates of 3.62% (95% CI: 3.51-3.75) and 4.91% bearing type and patellar surface showed a significant (95% CI: 4.38-5.50) for cemented versus noncemented benefit, and all constructs resulted in clinical improvement primary TKAs, respectively.

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© 2017 American Academy of Orthopaedic Surgeons

Chapter 18: Outcomes of Primary Total Knee Arthroplasty

Figure 2

Graph shows Kaplan-Meier estimates of the cumulative percentage probability of a first revision of primary total knee replacement by age and at increasing years after primary surgery. (Adapted with permission from the Australian Orthopaedic Association: National Joint Arthroplasty Registry Annual Report 2015. Available at: https:// aoanjrr.sahmri.com/annual-reports-2015. Accessed July 6, 2016.)

Improving Survivorship Jeffrey Lange, MD; Patricia D. Franklin, MD, MBA, MPH; David C. Ayers, MD

New Technologies Despite its excellent track record, TKA is not a perfect intervention. Close to 20% of patients may experience dissatisfaction after surgery.15 In addition to patient dissatisfaction, a certain percentage of primary TKAs fail, requiring revision surgery. A recent United States multicenter retrospective review of 844 failed TKAs requiring revision documented the incidence of failure mechanisms,16 with aseptic loosening, instability, infection, and polyethylene wear among the most common mechanisms affecting the original implant longevity. In an effort to optimize TKA surgery outcomes, many investigators continue to develop new strategies to tackle these challenges. Two current areas of focus have been fixation methods and alternative bearing surfaces.

© 2017 American Academy of Orthopaedic Surgeons

As noted previously, cemented TKA constructs have been considered the gold standard for use in primary TKA. With the introduction of highly porous metal technology, however, short-term radiographic survivorship is promising. For instance, a recent randomized controlled trial compared traditional modular cemented tibial components to highly porous metal tibial components, either cemented or noncemented, in primary TKA.17 The allcause revision rates were equivalent among constructs at a mean of 5 years. A retrospective review of 115 TKAs using porous tantalum implants noted a 95.7% cumulative survivorship at a mean of 7 years’ follow-up, with no evidence of aseptic loosening as cause for revision.18 Another study reported on a prospectively collected cohort of 105 consecutive porous tantalum TKAs, demonstrating no aseptic loosening at a minimum 3 years follow-up and an overall revision rate of 1%.19 Further studies are necessary to clarify the role and long-term results of using highly porous metal surfaces in the setting of primary TKA. The advent of highly cross-linked polyethylene has provided the potential for improved wear characteristics of TKA designs. Multiple investigators have assessed wear rates at midterm and long-term follow-up, and the results are not yet clear. The Australian Orthopaedic Association National Joint Arthroplasty Registry was assessed regarding differential wear rates between highly crosslinked and conventional polyethylene bearing TKAs over a 5- to 10-year period.20 Study results indicated improved wear rates at 5 to 10 years for some designs, but not for others. Wear rate changes were both design and vendor

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2: Knee

Furthermore, most reports indicate that most primary TKAs being performed worldwide use cement. In 2015, the Australian registry reported using noncemented technique in 16.5% of all primary TKAs.1 The British registry demonstrated an even more dramatic trend, with noncemented TKA constructs comprising 2.5% of all knee arthroplasty procedures in 2014.2 Thus, whereas some reports suggest reasonable outcomes after ­noncemented TKA in specific situations, many large-scale reports suggest that cemented primary TKA remains the gold standard and, on average, confers superior survivorship.

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specific. In a prospective randomized study evaluating the performance of highly cross-linked versus conventional polyethylene, a single implant system was used in patients undergoing simultaneous bilateral TKA.21 Study results indicated no radiographic or clinical differences between knees at a minimum follow-up of 5 years. Although no clear benefit to the use of highly cross-linked polyethylene in primary TKA has been reported, more long-term follow-­up is needed to clarify the role of this new technology. The development of new technologies, such as porous metal components and highly cross-linked polyethylene, has the potential to improve survivorship of ­primary TKAs going forward, although current data do not demonstrate that these technologies confer survivorship benefits. Therefore, routine use of these new technologies in general orthopaedic practice is not yet supported. Scoring Systems Philip C. Noble, PhD

2: Knee

Scoring systems provide a numerical rating of each patient’s outcome after TKA. The scores generated through administration of outcome instruments (typically validated patient questionnaires) provide the most concise, clear measure, especially when comparing large groups of patients and treatments. In the past, outcome scores were generated by the treating surgeon during systematic assessment of the patient. Recent focus has shifted toward the patient’s own assessment of his or her pain and function before and after TKA, as well as the extent to which his or her expectations have been fulfilled by the procedure. Patient-reported outcomes measures (PROM), traditionally used in clinical research, have now moved into routine clinical practice. These scoring systems are generally measures of the patient’s global or disease-specific health. Global scoring systems consist of one or more domains relating to a particular facet of health (such as pain, function, satisfaction, or mental health). Summary global scores may be calculated by combining related domain scores that reflect the patients’ overall physical health (physical composite score) or emotional health (mental composite score); physical composite score and mental composite score have proven to be very useful measures in TKA patients. Despite methodologic differences, scoring systems that have undergone formal validation have broad applicability and are generally accepted for measurement of outcomes after joint arthroplasty.22 When developing or selecting a scoring system for quantification of outcomes, it must be recognized that every outcome score will be affected by the multidimensional facets of each patient’s experience. Thus, all outcome measures

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are subject to the attitudes, abilities, and expectations of patients as well as to their motivations to undergo surgery. Generic and Disease-Specific Outcome Measures One approach to assessing the outcome of knee arthroplasty is through evaluation of the general health of the patient before and after treatment. This approach assumes that the value of medical intervention is reflected in a measurable improvement in patients’ health-related quality of life. Thus, items that assess a patient’s physical health, physiologic function, emotional health, and social function are expected to provide insight into the effect of a given treatment on the overall outcome of a broad demographic of patients. One of the most frequently cited instruments for measurement of generic health outcomes is the Medical Outcomes Study 36-Item Short Form (SF-36), which was developed to measure the effect of interventions, including TKA, on the overall health and quality of life of patients23,24 (Table 2). Demand resulted in the development and validation of a shorter version, the 12-Item Short Form (SF-12), which consists of the 12 items from the functional status and well-being sections of the SF-36 that were found to be most predictive of the original outcome score.3 The SF-36 and SF-12 have been used extensively to evaluate patients before and after treatment of a wide variety of disease and surgical procedures, including TKA. Although scores generated by the SF-36 and SF-12 instruments demonstrate that the patient’s quality of life dramatically improves after TKA, these instruments are not highly sensitive or responsive to subtle changes among individual subjects with varied severity of knee problems or levels of recovery.25 They are also affected by the patients’ medical and musculoskeletal comorbid conditions. To provide a more comprehensive assessment of patient outcomes, both a generic and a specific outcome measure are often administered. Disease-specific outcome measures in TKA patients focus all questions on the knee to specifically assess symptoms and function of that individual joint.26 Because disease-specific scales have a narrower focus, they are often more responsive than generic health measures. The most commonly used disease-specific outcome measures are the Western Ontario and McMaster Universities Arthritis Index (WOMAC), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Oxford Knee Score.27 The KOOS was developed as an extension of the WOMAC, using some of its subscales to measure the condition of the knee in younger, more active patients who have early-stage osteoarthritis or knee symptoms28 (Table 2). Five scores are generated from the subscales of the KOOS (pain [9 items]; symptoms [7 items]; activities

© 2017 American Academy of Orthopaedic Surgeons

Chapter 18: Outcomes of Primary Total Knee Arthroplasty

Table 2

Generic and Disease-Specific Outcome Measurement Instruments Scoring System Medical Outcomes Study 36-Item Short Form

Section

Subsection

Functional status

Physical functioning Social functioning Role limitations attributed to physical problems

Well-being

Mental health Energy/fatigue Pain

Deductions

Overall evaluation of health Knee Society score

The new Knee Society score

Pain (50 points) Range of motion (25 points) Stability (25 points)

Flexion contracture Extension lag Malalignment

Function score (100 points)

Walking (50 points) Stair climbing (50 points)

Reliance on walking aids

Objective knee score (100 points)

Anteroposterior alignment (25 points) Stability/instability (25 points) Range of motion (25 points) Symptoms (25 points)

Flexion contracture Extension lag Malalignment

Satisfaction score (40 points)

Pain level while sitting (8 points) Pain level while lying in bed (8 points) Knee function while getting out of bed (8 points) Knee function while performing light household duties (8 points) Knee function while performing recreational activities (8 points)

Expectations score (15 points)

Pain relief (5 points) Ability to perform ADL (5 points) Ability to perform leisure, recreational, or sports activities (5 points)

Functional activity score (100 points)

Walking and standing (30 points) Standard activities (30 points) Advanced activities (25 points) Discretionary activities (15 points)

2: Knee

Knee Society Score Short Form

Objective score (100 points)

Symptoms (3 items) Satisfaction (1 item)

Satisfaction while performing light household activities

Functional score (100 points)

How long can you walk? (20 points) Walking on an uneven surface (15 points) Climbing and descending stairs (15 points) Getting up from low couch or chair without arms (15 points) Running (20 points) Discretionary activities (15 points)

ADL = activities of daily living;

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Table 2

Generic and Disease-Specific Outcome Measurement Instruments (continued) Scoring System The Oxford 12Item Knee Score

Section

Subsection

Deductions

Pain Physical function Limitations

Knee Injury and Osteoarthritis Outcome Score

Self-administered queries

Pain (9 items) Symptoms (7 items) Function during ADL (17 items) Sport and recreation function (5 items) Quality of life (4 items)

Total Knee Function Questionnaire

Symptoms and activities

ADL (17 items) Movement and lifestyle activities (8 items) Recreational activities (8 items)

Additional items

Walking and running (5 items) Satisfaction (1 item) Activity level and expectations (3 items) Pain and other symptoms (4 items) Patient information (9 items)

Patient expectations

Pain (1 item) Psychologic well-being (1 item) Physical functions (15 items)

Knee Replacement Expectations Survey

2: Knee

of daily living function [17 items]; sport and recreation function [5 items]; and quality of life [4 items]) using item responses on a five-point Likert scale. The KOOS has been demonstrated as a valid, reliable, and responsive assessment instrument, especially for patients with expectations of physical activity or for those investigating physical function as a primary outcome. A CAT (computer adaptive technology) version of the KOOS that is under development will minimize the number of questions a patient answers while improving the accuracy of the score by using an item bank of questions.29 The 12-Item Oxford Knee Score (Oxford-12) was developed to assess the health outcomes of TKA patients on the basis of responses to 12 items that query pain, physical function, and limitations associated with the knee, each scored on a five-point scale26 (Table 2). The scoring system expresses the status of the knee in terms of a single score, rather than as separate subscores, and has demonstrated reliability and validity. The Oxford-12 has been considered a simple and reliable tool for assessment of outcome. However, because there is only one score, the ability to evaluate improvement in pain relief or improvement in function as discrete scores is not possible. This limitation is significant, because pain relief and functional improvement after TKA may be different.

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Functional Rating Systems Although knee arthroplasty primarily aims to relieve the pain of joint degeneration, an important goal for most patients is maximum restoration of function. The functional outcome of the procedure is often linked to the patient’s satisfaction with the procedure and has assumed greater importance as increasingly younger and more active patients have undergone the procedure. Functional rating systems have been designed with a primary focus on the ability of patients to participate in activities related to daily living, sports, and recreation. Thus, the ability of PROM to provide separate scores for function is considered very important. Another tool that may be used to measure knee function is the Total Knee Function Questionnaire, which is a self-administered instrument that collects information relating to physical activities in terms of their importance to each patient, the ­frequency with which each patient performs the activity, and the occurrence of symptoms when the patient performs the activity30 (Table 2). The Total Knee Function Questionnaire queries participation in 33 different activities, ranging from least demanding (walking and standing) to most demanding (running, downhill skiing); these are condensed from a larger battery of activities considered in pilot studies. Additional items ask patients about satisfaction with

© 2017 American Academy of Orthopaedic Surgeons

Chapter 18: Outcomes of Primary Total Knee Arthroplasty

TKA outcome and the extent to which the outcome has fulfilled expectations. Applications of PROM in Clinical Practice David C. Ayers, MD; Patricia D. Franklin, MD, MBA, MPH; Jeffrey Lange, MD

© 2017 American Academy of Orthopaedic Surgeons

Philip C. Noble, PhD

Performance-based tools, such as the timed up-and-go test39 and the 6-minute walk test,40 examine changes in physical function after TKA and capture objective information about patients’ actual function that is not evaluated by patient-reported measures. Unlike patient-­ reported measures, performance-based measures are derived from objective measures of function rather than from the patient’s perceived function and are not bodypart or body-function specific.41 One study of TKA patients has shown poor correlation between preoperative patient-reported measures (WOMAC and SF-36) and a performance-based measure (timed up-and-go test), highlighting the importance of both types of tests for a comprehensive assessment of disability.42 Recently, an expert group of 138 clinicians and researchers from 16 countries was commissioned to recommend a set of performance-based tests for use following TKA. The Osteoarthritis Research Society International consensus group suggested five tools: 30-second chair stand test, 40-meter fast-paced walk test, stair-climb test, timed upand-go test, and 6-minute walk test. The first three were suggested as the minimal core set of performance-based tests for knee osteoarthritis.43 Further research is required to fully assess the psychometric properties of these measures (reliability and validity) and to define the minimally clinically important difference for relevant time points following TKA. 2: Knee

Routine use of PROM in clinical practice is in keeping with the Institute of Medicine’s vision for medicine in the 21st century: to use information technology to support patient-centered evidence-based decisions. PROM have moved into clinical practice for TKA patients.31,32 Orthopaedic surgeon reimbursement in the United States is currently increased by reporting PROM through a qualified clinical data repository in the Physician Quality Reporting System of the Centers for Medicare & Medicaid Services (CMS) program. Commercial insurance programs are expected to follow the lead of CMS. In Massachusetts, for example, there is a pilot pay-for-performance quality-reporting program offered by a commercial insurer, and patient-reported outcomes are increasingly being used as a measure of quality. As health care moves from a volume-based to a value-based reimbursement system, PROM are being used as the numerator of the value equation.33-35 PROM can be collected in a busy practice on a routine basis with data that is more than 85% complete at 1-year follow-up.31 Data collection should be invisible to the surgeon and be efficient enough not to affect/delay the flow of the patient visit. To accomplish this, Internet-based electronic platforms have been developed so data can be entered before the office visit (either in the waiting room or at home before the visit); real-time scoring, using computer adaptive technology, allows scores to be used for decision-making during the same office visit. PROM bring value to the visit by showing both the surgeon and the patient how the patient’s function and pain compare to that of age-matched control patients as well as how they have changed after treatment prescribed at the previous visit.31 The measures are increasingly used for shared decision-making, including when to proceed with elective TKA, and to gather objective data about a patient’s recovery after TKA.35 The addition of PROM to risk-adjustment models significantly increases the accuracy of models used to predict the risk of readmission after total joint arthroplasty.36,37 PROM have also been used to assess patient selection and timing of TKA surgery across the United States and have been added to modern joint arthroplasty registries. The combination of PROM with demographic data and information relating to implant selection and survivorship now enables registries to provide valuable feedback regarding factors associated with pain and function after TKA.38

Performance-Based Measures

Global Knee Rating Systems Philip C. Noble, PhD

A global knee rating system has been operationally defined as an outcome instrument that includes, at a minimum, assessments of pain, function, and range of motion and summarizes these outcomes as a single score on a global scale. The American Knee Society Clinical Rating System, or Knee Society Score (KSS), recognized some of the limitations of the earlier Hospital for Special Surgery Score and implemented a scoring method that has been widely adopted and supported.44 The KSS consists of two separate subscores, each on a 100-point scale (Table 2): the clinician-administered “Objective Knee Score” and the “Function Score.” This separation enables surgeons to assess patients’ knee conditions independent of any functional deterioration due to comorbidities. Psychometric testing has shown that the KSS Objective component has poor reliability with acceptable responsiveness, whereas the KSS Functional component has good reliability with questionable responsiveness.45 In view of these deficiencies, both of these KSS subscores are often administered

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2: Knee

to assess outcome, a practice that had previously been widely accepted in clinical use.45 Given that the KSS functional component is only based on the patient’s ability to walk and climb stairs, the KSS is not indicative of a patient’s ability to perform functional tasks that are more demanding (such as running, cycling, and yoga). Thus the KSS functional component has a marked ceiling effect, with many patients receiving the maximum possible score. This deficiency has become increasingly apparent in assessing contemporary TKA patients, approximately one-third of whom are 55 years or younger and who frequently participate in sporting and workout activities.46 In recognition of this deficiency, a new KSS System was developed and formally validated in 2011 to account for the preoperative patient expectations, satisfaction, and physical activities of the younger, more diverse population of contemporary TKA patients.47 This new KSS preserves the original objective and functional subscores and includes items relating to patient satisfaction; it also surveys the patient’s ability to participate in a broad range of activities, both preoperatively and at follow-­up (Table 2). The functional activity score in the new KSS places greater emphasis on the patient’s assessment of the importance of specific activities by allowing him or her to select some of the activities forming the basis of the assessment of outcome; in addition, a wide variety of activities, ranging from walking to running, is included. Despite the advantages of the new KSS, a deficiency revealed in initial trials was a higher-than-expected incidence of incomplete responses during self-administration.47 This resulted in the development and validation of a short-form version of the new KSS to increase the usefulness of the instrument for routine follow-up of patients after TKA48 (Table 2). During validation, the short form still provided acceptable discrimination between clinically different groups of patients before and after TKA, with virtually the same estimated effect size as the original functional activities subscale of the new KSS. This resulted in the conclusion that the short-form version of the KSS was practical, valid, reliable, and responsive for assessing functional outcome of TKA. It was recommended that the long-form version of the new KSS be used for research studies and for more sensitive measurement of the outcomes of individual patients. In addition, it was recommended that the short-form version be adopted in general clinical practice for use with large patient populations based on expected improvement in the rate of patient completion and ease of administration.48

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Patient Satisfaction Christopher Kim, MD, MSc; Rajiv Gandhi, MS, MD, FRCSC; Nizar N. Mahomed, MD, MPH, ScD

Patient satisfaction is an important component of success following TKA. Despite improvements in pain and function imparted by TKA, patient satisfaction rates following TKA have been reported at 85% or less in several studies.15,49-51 Many investigators have begun to focus on optimizing patient satisfaction in an effort to improve overall subjective success rates following TKA. Although there are several studies on this topic, many conflicting reports exist about determinants of satisfaction following TKA. Determinants of Satisfaction in TKA Most studies of patient satisfaction have focused on factors related to a patient’s subjective experience following TKA.52 Lack of improvement in pain after TKA has been shown to be the most significant predictor of dissatisfaction.53,54 It has been consistently demonstrated that unmet preoperative patient expectations predict dissatisfaction.15,50,53 One study reported that satisfaction after TKA was primarily determined by patients’ expectations and not their absolute level of function.50 In a large study of more than 1,700 patients, the main contributing factor to patient dissatisfaction was not meeting patient expectations.15 According to a related study,53 patients satisfied with knee arthroplasty had had their expectations met. Counseling patients on realistic expectations of surgical recovery appears paramount for optimizing satisfaction. Satisfaction following TKA has been associated with several other patient factors. Some investigators have shown increasing age to be a risk factor for dissatisfaction following TKA, whereas others have shown no correlation between age and postoperative satisfaction.15,50,53,55 Many authors have shown that patient sex does not affect satisfaction following TKA.15,50,53,55 Poor mental health has been linked to dissatisfaction after TKA.53 One study recognized helplessness as a significant negative predictor of WOMAC score change and found that patients reporting higher levels of mental health dysfunction had a statistically higher chance of being dissatisfied 1 year after TKA.56 One study noted that patients with poorer preoperative WOMAC scores for pain and function exhibited higher postoperative dissatisfaction rates, whereas another has shown no significant effect of preoperative WOMAC scores on patient satisfaction.15,57 Some investigators have linked the presence of back pain, depression, and other painful joints to higher dissatisfaction rates following TKA, whereas others have found no relationship between medical comorbidity and satisfaction15,53,57 Interestingly, one study noted higher satisfaction rates following TKA

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Chapter 18: Outcomes of Primary Total Knee Arthroplasty

in patients with rheumatoid arthritis than in patients with a preoperative diagnosis of osteoarthritis, osteonecrosis, or posttraumatic arthritis.49 Several factors extrinsic to patients may also affect postoperative satisfaction.52 Choice of anesthetic protocol, surgical technique, and use of navigation have all been implicated in the degree of patient satisfaction after TKA.58-60 Several studies have reported that component choices in TKA do not correlate with postoperative patient satisfaction.49,61-65 One study has particularly shown that discharge destination, namely inpatient versus home-based rehabilitation, does not provide a significant difference in patient satisfaction.66 Not surprisingly, the occurrence of a postoperative complication requiring hospital admission has been associated with dissatisfaction.15 Summary TKA is a highly successful surgery, providing sustainable relief and improved quality of life to its recipients. Many factors affect the success of TKA, some of which have been elucidated and some of which remain obscure. Outcomes instruments exist to help in the understanding of the objective and subjective patient experience following TKA. Continued monitoring of long-term results following TKA is advocated, along with continued study of new technologies and incorporation of outcomes instruments in the study of TKA to optimize this already highly successful intervention.

• Overall survivorship rates of primary TKA are 90% or higher in most long-term follow-up studies, including clinical and registry-based studies. • Many TKA designs and strategies have high success rates, although not all designs and strategies have comparable success rates. • Recent focus has shifted from surgeon-reported to patient-reported outcomes to assess a patient-­ centered concept of success following TKA. • Patient satisfaction following TKA is multifactorial and includes factors intrinsic and extrinsic to patients. • Patient satisfaction rates following TKA have been determined to be 85% or lower in multiple studies.

© 2017 American Academy of Orthopaedic Surgeons

1. Australian Orthopaedic Association: National Joint Arthroplasty Registry—Annual Report 2015. 2015. Available at: https://aoanjrr.sahmri.com/annual-reports-2015. Accessed July 6, 2016. This report summarizes the results of a large number of TKAs performed in Australia over more than 1 decade. Level of evidence: II. 2. 12th Annual Report: National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. Available at: http://www.njrcentre.org.uk/njrcentre/. Accessed July 6, 2016. This report summarizes the results of a large number of total joint arthroplasties performed in England, Wales, Northern Ireland, and the Isle of Man over more than 1 decade. Level of evidence: II. 3. Argenson J-N, Boisgard S, Parratte S, et al; French Society of Orthopedic and Traumatologic Surgery (SOFCOT): Survival analysis of total knee arthroplasty at a minimum 10 years’ follow-up: A multicenter French nationwide study including 846 cases. Orthop Traumatol Surg Res 2013;99(4):385-390. Medline  DOI This retrospective study analyzes survivorship of 846 TKAs from multiple centers at a minimum follow-up of 10 years. Level of evidence: IV. 4. Meftah M, Ranawat AS, Ranawat CS: Ten-year follow-up of a rotating-platform, posterior-stabilized total knee arthroplasty. J Bone Joint Surg Am 2012;94(5):426-432. Medline  DOI 2: Knee

Key Study Points

Annotated References

This prospective review of 138 consecutive mobile-­ bearing TKAs in 117 patients shows an all-cause revision rate of 97.7% at a mean follow-up of 10 years. Level of evidence: IV. 5. Hopley CD, Dalury DF: A systematic review of clinical outcomes and survivorship after total knee arthroplasty with a contemporary modular knee system. J Arthroplasty 2014;29(7):1398-1411. Medline  DOI This systematic review of clinical outcomes and survivorship following TKA with a single system is based on a review of both clinical studies and registry reports. 6. Paxton EW, Furnes O, Namba RS, Inacio MC, Fenstad AM, Havelin LI: Comparison of the Norwegian knee arthroplasty register and a United States arthroplasty registry. J Bone Joint Surg Am 2011;93(suppl 3):20-30. Medline  DOI This study compares results between two large joint arthroplasty registries. Cumulative survivorship of TKAs in each registry at 7-year follow-up (94.8% and 96.3%) is compared, as are causes for revision and differing perioperative characteristics between the two registry cohorts.

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7. Pabinger C, Berghold A, Boehler N, Labek G: Revision rates after knee replacement. Cumulative results from worldwide clinical studies versus joint registers. Osteoarthritis Cartilage 2013;21(2):263-268. Medline  DOI This systematic review of clinical studies reporting revision rates following knee arthroplasty compared both rates found through systematic review and rates published in multiple joint arthroplasty registries. Overall revision rates were similar in clinical and registry-based data, but significant differences in revision rates published by developers and registries were noted. 8. Verra WC, van den Boom LG, Jacobs W, Clement DJ, Wymenga AA, Nelissen RG: Retention versus sacrifice of the posterior cruciate ligament in total knee arthroplasty for treating osteoarthritis. Cochrane Database Syst Rev 2013;10(10):CD004803. Medline A systematic review of the literature yielded 17 randomized controlled trials that studied differential outcomes between cruciate-sacrificing and cruciate-retaining TKAs. No clinically significant differences in outcome were found between the two designs. 9. Li N, Tan Y, Deng Y, Chen L: Posterior cruciate-retaining versus posterior stabilized total knee arthroplasty: A meta-analysis of randomized controlled trials. Knee Surg Sports Traumatol Arthrosc 2014;22(3):556-564. Medline  DOI

2: Knee

This meta-analysis of eight randomized controlled trials compared results of cruciate-sacrificing and cruciate-­ retaining TKAs. Cruciate-sacrificing TKAs conferred modest flexion benefits; otherwise, both interventions have similar clinical and functional outcomes. Level of evidence: II. 10. Kim YH, Park JW, Kim JS, Kulkarni SS, Kim YH: Longterm clinical outcomes and survivorship of press-fit condylar sigma fixed-bearing and mobile-bearing total knee prostheses in the same patients. J Bone Joint Surg Am 2014;96(19):e168. Medline  DOI This is a retrospective review of prospectively collected data from 444 consecutive patients undergoing bilateral TKA who received one fixed-bearing and one mobile-­ bearing implant; the same systems were used in all patients. No significant clinical or survivorship differences were evident at a mean follow-up of 12.1 years. Level of evidence: II.

This meta-analysis of 14 randomized controlled trials compared the clinical outcomes of mobile- versus fixed-­ bearing TKAs; no significant differences were found between groups with respect to Hospital for Special Surgery scores, Knee Society Scores, or range of motion at final follow-up. 13. Ranawat CS, Meftah M, Windsor EN, Ranawat AS: Cementless fixation in total knee arthroplasty: Down the boulevard of broken dreams - affirms. J Bone Joint Surg Br 2012;94(11suppl A):82-84. Medline  DOI A review of clinical and registry data concerning survivorship, clinical outcomes, and complications after c­ emented or noncemented TKAs indicated that cement fixation conferred overall greater survivorship and supported cement fixation as the current gold standard. 14. Gandhi R, Tsvetkov D, Davey JR, Mahomed NN: Survival and clinical function of cemented and uncemented prostheses in total knee replacement: A meta-analysis. J Bone Joint Surg Br 2009;91(7):889-895. Medline  DOI 15. Bourne RB, Chesworth BM, Davis AM, Mahomed NN, Charron KD: Patient satisfaction after total knee arthroplasty: Who is satisfied and who is not? Clin Orthop Relat Res 2010;468(1):57-63. Medline  DOI In this cross-sectional study of patient satisfaction after 1,703 primary TKAs performed in the province of Ontario, authors found that 81% of patients expressed overall satisfaction after TKA, and the most significant factors associated with primary TKA dissatisfaction were expectations not met, a low 1-year WOMAC score, a low preoperative WOMAC score, and a complication requiring hospital readmission. Level of evidence: II. 16. Schroer WC, Berend KR, Lombardi AV, et al: Why are total knees failing today? Etiology of total knee revision in 2010 and 2011. J Arthroplasty 2013;28(8suppl):116-119. Medline  DOI In a retrospective review of all primary revision TKAs performed at six centers over a 2-year period, failures were stratified by mechanism and to show differential predominance of failure mechanism as a function of primary implant time in situ.

11. Ferguson KB, Bailey O, Anthony I, James PJ, Stother IG, M J G B: A prospective randomised study comparing rotating platform and fixed bearing total knee arthroplasty in a cruciate substituting design: Outcomes at two year follow-up. Knee 2014;21(1):151-155. Medline  DOI

17. Pulido L, Abdel MP, Lewallen DG, et al: The Mark Coventry Award: Trabecular metal tibial components were durable and reliable in primary total knee arthroplasty: A randomized clinical trial. Clin Orthop Relat Res 2015;473(1):34-42. Medline  DOI

In this prospective study of 352 patients randomized to receive a fixed- or mobile-bearing TKA using a single system, clinical outcomes at 2 years showed no significance between groups. Level of evidence: I.

Patients undergoing primary TKA were randomized to one of three groups: cemented fixation, cemented fixation (porous metal), and noncemented fixation (porous metal). The 5-year results showed no differences in survivorship or clinical outcomes among groups. Level of evidence: I.

12. Smith H, Jan M, Mahomed NN, Davey JR, Gandhi R: Meta-analysis and systematic review of clinical outcomes

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comparing mobile bearing and fixed bearing total knee arthroplasty. J Arthroplasty 2011;26(8):1205-1213. Medline  DOI

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Chapter 18: Outcomes of Primary Total Knee Arthroplasty

18. Kwong LM, Nielsen ES, Ruiz DR, Hsu AH, Dines MD, Mellano CM: Cementless total knee replacement fixation: A contemporary durable solution—affirms. Bone Joint J 2014;96-B(11suppl A):87-92. Medline  DOI A retrospective review of 115 knees undergoing primary noncemented TKA with porous tantalum implants (mean follow-up, 7 years) showed that no revisions had been required for aseptic loosening and that overall implant survivorship was 95.7%. 19. Helm AT, Kerin C, Ghalayini SR, McLauchlan GJ: Preliminary results of an uncemented trabecular metal tibial component in total knee arthroplasty. J Arthroplasty 2009;24(6):941-944. Medline  DOI 20. de Steiger RN, Muratoglu O, Lorimer M, Cuthbert AR, Graves SE: Lower prosthesis-specific 10-year revision rate with crosslinked than with non-crosslinked polyethylene in primary total knee arthroplasty. Acta Orthop 2015;86(6):721-727. Medline  DOI Using data from the Australian National Joint Arthroplasty Registry, 302,214 primary TKAs using non–crosslinked polyethylene were compared with 83,890 primary TKAs using cross-linked polyethylene. The overall revision rate at 10-year follow-up was found to be lower for cross-linked polyethylene systems, but this effect was prosthesis-specific. 21. Kim Y-H, Park J-W: Comparison of highly cross-linked and conventional polyethylene in posterior cruciate-substituting total knee arthroplasty in the same patients. J Bone Joint Surg Am 2014;96(21):1807-1813. Medline  DOI

22. Ramkumar PN, Harris JD, Noble PC: Patient reported outcome measures after total knee arthroplasty: A systematic review. Bone Joint Res 2015;4(7):120-127. Medline  DOI

25. Ko Y, Lo NN, Yeo SJ, et al: Comparison of the responsiveness of the SF-36, the Oxford Knee Score, and the Knee Society Clinical Rating System in patients undergoing total knee replacement. Qual Life Res 2013;22(9):2455-2459. Medline  DOI In a statistical analysis of outcomes data collected from 702 TKA patients using three different instruments, the Oxford Knee Score and the pain subscale of the KSS were found to be more responsive than most of the subscales of the SF-36. 26. Dawson J, Fitzpatrick R, Murray D, Carr A: Questionnaire on the perceptions of patients about total knee replacement. J Bone Joint Surg Br 1998;80(1):63-69. Medline  DOI 27. Jenny JY, Diesinger Y: The Oxford Knee Score: Compared performance before and after knee replacement. Orthop Traumatol Surg Res 2012;98(4):409-412. Medline  DOI The floor and ceiling effects of the Oxford Knee Score were examined in a population of 200 TKA patients (100 preoperatively; 100 at 1 year postoperatively) and compared to the KSS. The floor effect was absent before surgery but was substantial (33%) after surgery, whereas the ceiling effect was virtually absent in both instances. The internal consistency and discrimination of the Oxford Knee Score were judged to be excellent. 28. Roos EM, Roos HP, Lohmander LS, Ekdahl C, Beynnon BD: Knee Injury and Osteoarthritis Outcome Score (KOOS): Development of a self-administered outcome measure. J Orthop Sports Phys Ther 1998;28(2):88-96. Medline  DOI 29. Peer MA, Lane J: The Knee Injury and Osteoarthritis Outcome Score (KOOS): A review of its psychometric properties in people undergoing total knee arthroplasty. J Orthop Sports Phys Ther 2013;43(1):20-28. Medline  DOI A systematic review of the psychometric properties of the KOOS in patients undergoing TKA (six studies fulfilled the inclusion criteria), the KOOS demonstrated a high level of responsiveness and clinically acceptable reliability; however, the reliability and construct validity of the KOOS sport and recreation subscale was poor.

A systematic review of PROM after TKA was performed of 38 articles that reported outcomes from 47 different patient-reported outcome measures; however, only six articles acknowledged all “gold standard” psychometric properties. Those most commonly studied were the Oxford Knee Score, new KSS, Osteoarthritis Outcome Score, and WOMAC. A single valid instrument addressing patients’ priorities after TKA has not yet been identified.

30. Weiss JM, Noble PC, Conditt MA, et al: What functional activities are important to patients with knee replacements? Clin Orthop Relat Res 2002;404:172-188. Medline  DOI

23. Ware JE Jr, Gandek B: Overview of the SF-36 Health Survey and the International Quality of Life Assessment (IQOLA) Project. J Clin Epidemiol 1998;51(11):903-912. Medline  DOI

31. Ayers DC, Zheng H, Franklin PD: Integrating patient-reported outcomes into orthopaedic clinical practice: Proof of concept from FORCE-TJR. Clin Orthop Relat Res 2013;471(11):3419-3425. Medline  DOI

24. Ware J Jr, Kosinski M, Keller SD: A 12-Item Short-Form Health Survey: Construction of scales and preliminary

© 2017 American Academy of Orthopaedic Surgeons

2: Knee

The results of a prospectively enrolled cohort of patients undergoing bilateral TKA were reviewed, using the same implant system, who received conventional polyethylene in one knee and highly cross-linked polyethylene in the contralateral knee. At mean follow-up of 5.9 years, no significant differences in radiographic or clinical outcomes were noted between groups. Level of evidence: II.

tests of reliability and validity. Med Care 1996;34(3):220233. Medline  DOI

This article documents successful integration of patient-­ reported outcomes into a busy orthopaedic practice. Standardized patient-reported outcomes are invaluable in informing treatment and in making shared decisions

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regarding treatment. This article provides evidence that the methods can be extrapolated to various settings. 32. Ayers DC, Bozic KJ: The importance of outcome measurement in orthopaedics. Clin Orthop Relat Res 2013;471(11):3409-3411. Medline  DOI The use of patient-reported outcomes in orthopaedic registries in the era of public reporting of outcome data and value-based reimbursement is discussed. 33. Franklin PD, Lewallen D, Bozic K, Hallstrom B, Jiranek W, Ayers DC: Implementation of patient-reported outcome measures in U.S. Total joint replacement registries: Rationale, status, and plans. J Bone Joint Surg Am 2014;96 (suppl 1):104-109. Medline  DOI Current reporting of patient-reported outcomes in US registries is reviewed, illustrating significant variation in collection rates reported. 34. Franklin PD, Allison J, Ayers DC: Beyond joint implant registries: A patient-centered research consortium for comparative effectiveness in total joint replacement. JAMA 2012;308(12):1217-1218. Medline  DOI In this article, the research program funded by the Agency for Healthcare Research and Quality, the Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement is discussed, which has pioneered a patient-centered approach to the collection of arthroplasty data from more than 200 centers in 26 states in the United States.

2: Knee

35. Ayers DC, Franklin PD: Joint replacement registries in the United States: A new paradigm. J Bone Joint Surg Am 2014;96(18):1567-1569. Medline  DOI This commentary provides an overview of existing total joint arthroplasty registries and outlines the need for arthroplasty registries to collect and report data in addition to survivorship of the implant. Modern registries have moved to a patient-centered approach rather than an implant-centered approach. 36. Ayers DC, Li W, Oatis C, Rosal MC, Franklin PD: Patient-reported outcomes after total knee replacement vary on the basis of preoperative coexisting disease in the lumbar spine and other nonoperatively treated joints: The need for a musculoskeletal comorbidity index. J Bone Joint Surg Am 2013;95(20):1833-1837. Medline  DOI This prospective study of a cohort of TKA patients highlights the influence of preoperative musculoskeletal pain in low back and nonsurgical joints on postsurgery functional improvements. 37. Ayers DC, Fehring T, Odum S, Franklin PD: Using joint registry data from FORCE-TJR to improve the accuracy of risk-adjustment prediction models for thirty-day readmission after total hip replacement and total knee replacement. J Bone Joint Surg Am 2015;97(8):668-671. Medline  DOI The authors demonstrate the importance of adding clinical measures to administrative data in risk-adjustment

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models as an effort to provide more accurate information on patients at higher risk for readmission after total joint arthroplasty. 38. Ayers DC, Li W, Harrold L, Allison J, Franklin PD: Preoperative pain and function profiles reflect consistent TKA patient selection among US surgeons. Clin Orthop Relat Res 2015;473(1):76-81. Medline  DOI In analyses of data from a large cohort of TKA patients in which surgeons used consistent patient criteria in scheduling surgery, all patients reported significant levels of pain and functional impairment preoperatively. 39. Podsiadlo D, Richardson S: The timed “Up & Go”: A test of basic functional mobility for frail elderly persons. J Am Geriatr Soc 1991;39(2):142-148. Medline  DOI 40. Guyatt GH, Sullivan MJ, Thompson PJ, et al: The 6-minute walk: A new measure of exercise capacity in patients with chronic heart failure. Can Med Assoc J 1985;132(8):919923. Medline 41. Dobson F, Hinman RS, Hall M, Terwee CB, Roos EM, Bennell KL: Measurement properties of performance-based measures to assess physical function in hip and knee osteoarthritis: A systematic review. Osteoarthritis Cartilage 2012;20(12):1548-1562. Medline  DOI The authors performed a systematic review of measurement properties of performance-based measures to assess physical function in patients with hip and/or knee osteoarthritis; 24 of 1,792 publications were eligible for inclusion, and 21 performance-based measures were evaluated, including 15 single-activity measures and 6 multiactivity measures. The 40-meter self-paced test was the best-­rated walk test, the 30-second chair stand test and timed up-and-go test were the best-rated sit-to-stand tests, and the Stratford battery as well as the Physical Activity Restrictions and Functional Assessment System were the best-­rated multiactivity measures. 42. Gandhi R, Tsvetkov D, Davey JR, Syed KA, Mahomed NN: Relationship between self-reported and performance-based tests in a hip and knee joint replacement population. Clin Rheumatol 2009;28(3):253-257. Medline  DOI 43. Dobson F, Hinman RS, Roos EM, et al: OARSI recommended performance-based tests to assess physical function in people diagnosed with hip or knee osteoarthritis. Osteoarthritis Cartilage 2013;21(8):1042-1052. Medline  DOI An expert group of 138 clinicians and researchers from 16 countries was commissioned to recommend a set of performance-based tests for use following TKA. The Osteoarthritis Research Society International advisory group suggested five tools: 30-second chair-stand test, 40-meter fast-paced walk test, stair-climb test, timed up-and-go test, and 6-minute walk test. The first three were suggested as the minimal core set of performance-based tests for knee osteoarthritis.

© 2017 American Academy of Orthopaedic Surgeons

Chapter 18: Outcomes of Primary Total Knee Arthroplasty

44. Insall JN, Dorr LD, Scott RD, Scott WN: Rationale of the Knee Society clinical rating system. Clin Orthop Relat Res 1989;248:13-14. Medline

52. Sitzia J, Wood N: Patient satisfaction: A review of issues and concepts. Soc Sci Med 1997;45(12):1829-1843. Medline  DOI

45. Lingard EA, Katz JN, Wright RJ, Wright EA, Sledge CB; Kinemax Outcomes Group: Validity and responsiveness of the Knee Society Clinical Rating System in comparison with the SF-36 and WOMAC. J Bone Joint Surg Am 2001;83-A(12):1856-1864. Medline

53. Scott CE, Howie CR, MacDonald D, Biant LC: Predicting dissatisfaction following total knee replacement: A prospective study of 1217 patients. J Bone Joint Surg Br 2010;92(9):1253-1258. Medline  DOI

46. Dahm DL, Barnes SA, Harrington JR, Sayeed SA, Berry DJ: Patient-reported activity level after total knee arthroplasty. J Arthroplasty 2008;23(3):401-407. Medline  DOI 47. Noble PC, Scuderi GR, Brekke AC, et al: Development of a new Knee Society scoring system. Clin Orthop Relat Res 2012;470(1):20-32. Medline  DOI This article describes the process of development of the new Knee Society scoring system, including collection of comprehensive activity data from TKA patients, creation of a prototype scoring system, and final validation using item-response theory. Interesting data are presented regarding the activities and perceptions of contemporary TKA patients. 48. Scuderi GR, Sikorskii A, Bourne RB, Lonner JH, Benjamin JB, Noble PC: The Knee Society short form reduces respondent burden in the assessment of patient-reported outcomes. Clin Orthop Relat Res 2016;474(1):134-142. Medline  DOI

49. Robertsson O, Dunbar M, Pehrsson T, Knutson K, Lidgren L: Patient satisfaction after knee arthroplasty: A report on 27,372 knees operated on between 1981 and 1995 in Sweden. Acta Orthop Scand 2000;71(3):262-267. Medline  DOI 50. Noble PC, Conditt MA, Cook KF, Mathis KB: The John Insall Award: Patient expectations affect satisfaction with total knee arthroplasty. Clin Orthop Relat Res 2006;452(452):35-43. Medline  DOI 51. Mahomed N, Gandhi R, Daltroy L, Katz JN: The self-­ administered patient satisfaction scale for primary hip and knee arthroplasty. Arthritis 2011;2011:591253. Medline  DOI In this series on satisfaction with TKA, using a patient satisfaction scale that is valid and reliable as tested on TKA patients, the authors reported on 857 TKA patients and described an overall satisfaction rate of 88% at 1 year postoperatively.

© 2017 American Academy of Orthopaedic Surgeons

54. Dunbar MJ: Subjective outcomes after knee arthroplasty. Acta Orthop Scand Suppl 2001;72(301):1-63. Medline  DOI 55. Gandhi R, Davey JR, Mahomed NN: Predicting patient dissatisfaction following joint replacement surgery. J Rheumatol 2008;35(12):2415-2418. Medline  DOI 56. Gandhi R, Razak F, Tso P, Davey JR, Mahomed NN: Greater perceived helplessness in osteoarthritis predicts outcome of joint replacement surgery. J Rheumatol 2009;36(7):1507-1511. Medline  DOI 57. Gandhi R, Davey JR, Mahomed N: Patient expectations predict greater pain relief with joint arthroplasty. J Arthroplasty 2009;24(5):716-721. Medline  DOI 58. Thorsell M, Holst P, Hyldahl HC, Weidenhielm L: Pain control after total knee arthroplasty: A prospective study comparing local infiltration anesthesia and epidural anesthesia. Orthopedics 2010;33(2):75-80. Medline  DOI

2: Knee

This article describes the development and validation of the short-form version of the KSS system with a set of 497 TKA patients recruited from 15 medical institutions in the United States and Canada. The original set of 25 patient-­reported outcome items on the long-form version was reduced to only eight items (six function, one expectation, one satisfaction). The final short-form score was found to be valid, reliable, and responsive, with virtually the same estimated effect size as the functional activities subscale of the original new Knee Society scoring system.

This study investigated preoperative and postoperative predictors of dissatisfaction in 1,217 consecutive patients undergoing TKA, both before and 6 months afterward, using the SF-12 and Oxford Knee Score. Significant predictors at 1 year included the preoperative SF-12 mental component score, depression, pain in other joints, 6-month SF-12 score, and poor Oxford Knee Score pain subscale scores. The most significant predictor of dissatisfaction was a painful TKA.

This study compared local infiltration anesthesia with epidural anesthesia for postoperative pain relief in 85 patients; 76% percent of patients who had received local infiltration anesthesia were very satisfied with their postoperative pain control compared to 40% of patients who received epidural anesthesia. 59. Hernandez-Vaquero D, Noriega-Fernandez A, Suarez-Vazquez A: Total knee arthroplasties performed with a mini-incision or a standard incision: Similar results at six months follow-up. BMC Musculoskelet Disord 2010;11:27. Medline  DOI The authors matched 26 minimally invasive TKA incisions to 36 standard TKA incisions at 6 months postoperatively and found no differences between the groups in range of motion, KSS results, physical and mental SF-12 score, pain, satisfaction, or subjective improvement. 60. Spencer JM, Chauhan SK, Sloan K, Taylor A, Beaver RJ: Computer navigation versus conventional total knee replacement: No difference in functional results at two years. J Bone Joint Surg Br 2007;89(4):477-480. Medline  DOI

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61. Park JW, Kim YH: Simultaneous cemented and cementless total knee replacement in the same patients: A prospective comparison of long-term outcomes using an identical design of NexGen prosthesis. J Bone Joint Surg Br 2011;93(11):1479-1486. Medline  DOI This prospective randomized study evaluated the clinical and radiologic results of identical cemented or noncemented NexGen TKA prostheses implanted bilaterally in the same patient. Sequential simultaneous bilateral TKAs were performed in 50 patients (100 knees). There were no differences in KSS, WOMAC, range of motion, or patient satisfaction; no advantage of noncemented over cemented components in TKA was shown. 62. Harato K, Bourne RB, Victor J, Snyder M, Hart J, Ries MD: Midterm comparison of posterior cruciate-retaining versus -substituting total knee arthroplasty using the Genesis II prosthesis. A multicenter prospective randomized clinical trial. Knee 2008;15(3):217-221. Medline  DOI

65. Hui C, Salmon L, Maeno S, Roe J, Walsh W, Pinczewski L: Five-year comparison of oxidized zirconium and cobalt-chromium femoral components in total knee arthroplasty: A randomized controlled trial. J Bone Joint Surg Am 2011;93(7):624-630. Medline  DOI This study evaluated 40 consecutive patients (80 knees) who underwent simultaneous bilateral cruciate-retaining primary TKA. For each patient, knees were randomized to receive the oxidized zirconium femoral component, with the contralateral knee receiving the cobalt-chromium component; 5-year outcomes after TKA with oxidized zirconium and cobalt-chromium femoral components showed no significant differences in clinical, subjective, or radiographic outcomes. 66. Mahomed NN, Davis AM, Hawker G, et al: Inpatient compared with home-based rehabilitation following primary unilateral total hip or knee replacement: A randomized controlled trial. J Bone Joint Surg Am 2008;90(8):16731680. Medline  DOI

2: Knee

63. Kim TK, Chang CB, Kang YG, Kim SJ, Seong SC: Causes and predictors of patient’s dissatisfaction after uncomplicated total knee arthroplasty. J Arthroplasty 2009;24(2):263-271. Medline  DOI

64. Gioe TJ, Bowman KR: A randomized comparison of all-polyethylene and metal-backed tibial components. Clin Orthop Relat Res 2000;380:108-115. Medline  DOI

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Chapter 19

Outpatient Total Knee Arthroplasty Adolph V. Lombardi, Jr., MD, FACS  Dean J. Marshall, DO

Abstract

Keywords: total knee arthroplasty; outpatient TKA; outpatient arthroplasty; TKA Dr. Lombardi or an immediate family member has received royalties from Innomed, OrthoSensor, and Zimmer Biomet; serves as a paid consultant to OrthoSensor, Pacira Pharmaceuticals, and Zimmer Biomet; has received research or institutional support from Kinamed, OrthoSensor, Pacira Pharmaceuticals, and Zimmer Biomet; and serves as a board member, owner, officer, or committee member of The Hip Society, The Knee Society, The Mount Carmel Education Center at New Albany, and Operation Walk USA. Neither Dr. Marshall nor any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter.

© 2017 American Academy of Orthopaedic Surgeons

Total knee arthroplasty (TKA) has traditionally been thought of as an inpatient surgical procedure. The reasons vary, but most resistance to outpatient surgery is because of fear of pain control after surgery, limited mobility of the patients, and increased risk of complications.1 Over the past decade, it has been shown that length of stay in the hospital after TKA has declined without any increase in perioperative complications.2-8 This has been the main driver for the growing worldwide trend for outpatient joint arthroplasty.9 As the movement toward outpatient TKA progresses, the focus must be on the patient’s rapid recovery. This starts with defined protocols for patient selection, patient education, perioperative medical management, careful pain control, and well-coordinated postoperative care by surgeons and other medical providers (Table 1). It is important to highlight the objectives necessary for safe, successful outpatient TKA. 2: Knee

Total knee arthroplasty (TKA) is one of the most successful and frequently performed procedures by all orthopaedic surgeons. As with all joint arthroplasties, this procedure has evolved, and so has the arena in which these procedures are performed. As arthroplasty has progressed to the outpatient setting, the goal remains to provide patients with a durable, well-functioning joint while minimizing complications. Thorough patient selection and preoperative education is of paramount importance. Also, developing protocols with the medical and anesthesia teams regarding perioperative pain management is as critical as all intraoperative aspects of the procedure. Blood management and postoperative care should also be conducted carefully to decrease any complications and readmissions. These steps are necessary to make surgery in the outpatient setting feasible and reduce the risk to the patient. Outpatient TKA likely will continue to increase; however, not all patients who would benefit from TKA are candidates for outpatient arthroplasty. Providers, with the help of independent medical staff, need to be diligent in patient selection when moving patients from an inpatient to an outpatient setting.

Introduction

Patient Selection When evaluating a patient, the first and foremost factor to be considered is whether the specific disease pattern makes him or her a candidate for TKA. After the disease pattern is confirmed, inpatient versus outpatient TKA can be planned. Arthroplasty is an elective procedure focused on improving the patient’s mobility and quality of life. Most patients may have minimal medical comorbidities and are able to return to their previous living environment. An increasing number of physicians believe that the hospital is where sick people are treated, and if patients electing to undergo TKA are not sick, why should they have their surgery performed in the hospital? However, some patients with degenerative conditions of the knee also have myriad medical comorbidities. When these conditions place the patient at higher risk for complications, outpatient TKA should be avoided. All patients should undergo a medical examination by a licensed practitioner to be evaluated for underlying risk. The role of the medical team is to identify these issues, correct any comorbid conditions that can be corrected,

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Table 1

Outpatient Total Knee Arthroplasty Protocol 1. Patient Selection Orthopaedic evaluation and scheduling for surgery  Preoperative medical history and physical examination, including laboratory testing 2. Patient Education Educational materials are provided Physical therapy evaluation and instruction Preoperative educational class or video focused on outpatient total knee arthroplasty 3. Pain Management Night before surgery    Acetaminophen 1 g orally Day of surgery Acetaminophen 1 g orally   Celecoxib 400 mg orally (not used if cardiac history or other contraindications) Dexamethasone 10 mg IV   Scopolamine 1.5-mg patch (not used if history of BPH or glaucoma)   Pregabalin/gabapentin 600 mg orally (300 mg for patients older than 65 years) 4. Regional Anesthesia Sciatic nerve block: 15 mL 0.1% ropivacaine 2: Knee

Adductor canal block: 15 mL 0.5% bupivacaine 5. Intraoperative Medications

7. Home Medications Hydrocodone/acetaminophen 5/325 mg 1–2 pills every 4–6 h as required for pain Oxycodone 5 mg orally 1–2 pills every 4–6 h as required for severe pain Hydromorphone 2 mg 1 pill every 4–6 h as required for breakthrough pain Celecoxib 200 mg orally daily for 2 weeks 8. Blood Management Intravenous crystalloid hydration is started Tranexamic acid 1 g IV preoperatively (if no contraindications are present) Tranexamic acid 1 g IV 3 h after first dose (topical tranexamic acid is used in selected patient with increased risk of clot formation) 9. Surgery Light general anesthesia: propofol ± short-acting inhalants Ketamine 0.5 mg/kg IV before incision Preoperative IV antibiotic Minimum of 2 L crystalloid IV hydration Ondansetron 4 mg IV 10. Postoperative Care Minimum 1 L crystalloid IV hydration Ondansetron 4 mg IV as required for nausea/ vomiting

Pericapsular injection: 50 mL 0.5% ropivacaine, 0.5 mL 1:1000 epinephrine, 1 mL 30 mg ketorolac (not used in patients with renal impairment)

Promethazine 6.25 mg IV as required for nausea/ vomiting

Narcotics are titrated and used sparingly

Discharge instructions are provided by the nursing staff

6. Postoperative Medications

Urecholine 20 mg in male patients with BPH or risk of urinary retention

Hydromorphone 0.5 mg IV every 10 min as required up to 2 mg

Postoperative antibiotics are administered orally for 3 doses

Acetaminophen 1 g orally (4 h after first dose) Oxycodone 5 mg orally for pain levels 1–3

Aspirin 325 mg orally for 6 weeks for DVT prophylaxis (low–molecular weight heparin is used in obese or high-risk patients)

Hydrocodone/acetaminophen 5/325 mg 1 pill for pain levels 1–3

Battery-powered pneumatic-compression ambulatory calf pumps are worn for 2 weeks

Hydrocodone/acetaminophen 5/325 mg 2 pills for pain levels 4–10

Follow-up telephone communication at 24 h by nursing staff

Diazepam 2.5 mg IV as required for spasms

Office evaluation at 6 weeks

BPH = benign prostatic hyperplasia, DVT = deep vein thrombosis, IV = intravenously.

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and to identify the uncorrectable. A 2007 study reported a substantial number of new diagnoses during patient prescreening, and 2.5% of patients were deemed unacceptable as surgical candidates.10 After these patients are identified, they should undergo treatment in an acute care setting equipped to handle any unforeseen complications. A 2015 study reported that established diagnoses of chronic obstructive pulmonary disease, congestive heart failure, coronary artery disease, and cirrhosis are the most likely medical conditions to require additional intervention more than 24 hours after arthroplasty.11 Patients with these conditions should be of greatest concern when selecting for outpatient TKA. If minimal medical comorbidities are present and the patient is a candidate for outpatient arthroplasty, a conversation to access his or her comfort level with undergoing this outpatient procedure must occur. The expectations of the patient, family, and surgeon must all be in concordance. It should also be the priority of all involved that the patient has adequate family support and safety after he or she is discharged home. When moving patients to the outpatient setting, financial issues must be considered as well as medical issues. In the United States, outpatient TKA and total hip arthroplasty do not have a defined Medicare code, but there is a code for partial knee arthroplasties.12 Because of this, irrespective of the patient’s health status, Medicare guidelines state that the TKA must be coded as inpatient and performed in a hospital.

Many patients may be unaware of the ability to undergo TKA and be discharged on the same day. The patient may have a parent or sibling who underwent a similar procedure and were admitted to the hospital for an extended period. This treatment may represent the standard of care to them. Preoperative education regarding outpatient arthroplasty can eliminate any fears and explain the advantages of recovering from surgery at home. Full details of the procedure—pain management protocols, minimally invasive techniques, and physical therapy requirements after surgery—should be discussed before surgery to decrease the patient’s anxiety and improve his or her satisfaction with what will be done, while providing ample time for questions and answers. The surgeon, along with all who come in contact with the patient during preoperative education, should be of the same mindset and present a unified approach so that the patient feels comfortable and fully supported by all staff members. All patients should be provided with complete, up-todate educational materials before surgery, including the

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Pain Management A multimodal approach to pain control must be used, starting before surgery and including after the patient is discharged home. Many high-volume centers have successfully established pathways to reduce hospital length of stay and to expedite recovery13-21 that combine minimally invasive surgery with efficient anesthesia to decrease side effects and complications in the early postoperative period. The goal is to minimize pain, sedation, and nausea, while promoting early mobilization and safe discharge. Peripheral pain caused by surgical trauma can be separated into two categories: neurogenic and inflammatory.22,23 After incision, a cascade of nociceptive signals will cause the neurogenic pain and secondary inflammation will follow.22,23 Any multimodal approach should start with preoperative administration of analgesic and anti-­ inflammatory medications to reduce the perception of pain from reaching the central nervous system. This preemptive blocking of the nociceptive signals before painful stimulus has been proposed to decrease the intensity of postoperative pain;22 however, it is most effective when continued through the postoperative period.23 To combat these pain pathways, patients are typically given preoperative steroidal drugs and NSAIDs, regional

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Patient Education

step-by-step procedure from preoperative to postoperative stages. Most questions the patients have should be answered by the provided readings, but staff must always be available to answer specific and detailed queries. The patients must also be encouraged before surgery to view the facility and meet with staff (including but not limited to the physical therapy and nursing staff) providing postoperative care. The physical therapist can teach the patients how to use walkers or other ambulatory aides and help patients and family anticipate how to manage activities of daily living after discharge. Nursing staff will be able to explain to both patient and family proper wound care and how to assess for any signs of complications. Studies have shown that patient anxiety and fear can be decreased when he or she is aware of functional capacity in the immediate postoperative period.13-15 After proper patient selection, an established pathway is set with a multidisciplinary approach to rapid recovery. This has been shown to markedly reduce readmission rates and to reduce lengths of stay, while enabling earlier patient ambulatory ability.16 These protocols focus on perioperative pain control, surgical technique, and postoperative care, and should be set to improve the patient’s experience and to decrease any errors. The focus should be on educating the patient that outpatient TKA can be performed safely and with low risk of complications.

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anesthesia, and a nonnarcotic analgesic medication such as acetaminophen. The goal is to control the patient’s pain while minimizing narcotics to avoid side effects such as sedation, nausea, and hypoventilation, which will deter the rapid recovery process and make outpatient TKA difficult. Nausea and vomiting are aggressively controlled by administering antiemetics both before and after surgery and maintaining adequate hydration throughout the procedure. Medications such as dexamethasone can be used for both anti-inflammatory and antiemetic purposes; metoclopramide and scopolamine patches also can be sufficient options. In addition, other NSAIDs such as gabapentin and pregabalin can be used effectively to decrease pain and the need for narcotics.24 In addition to oral and intravenous medications, regional anesthesia in the form of adductor canal and partial sciatic nerve blocks are useful in pain management. Peripheral blocks have been found to improve pain control, decrease the need for narcotics, allow earlier function, and to reduce readmissions and hospital length of stay.25,26 Femoral nerve blocks have been shown to place patients at an increased risk of falls because of quadriceps muscle weakness;25,27 therefore, adductor canal blocks have been advocated.28 This type of block can be performed with ultrasonographic guidance and is purely sensory, thus avoiding any motor impairment of the quadriceps. Other methods that can be used are epidural and spinal injections, and both can be advantageous for pain control. Epidurals have been shown to decrease postoperative narcotic use.29,30 Narcotics should be avoided in these injections not only because of pruritus, nausea, and sedation, but also because patients will require more than 23 hours of observation. During the surgical procedure, local infiltration of the periarticular tissue with local anesthetics can help markedly with pain control.31 It has been shown that adding a long-acting narcotic to local injections can reduce the need for narcotics postoperatively as well as to improve pain control and range of motion.31 Recently, a liposomal-bound bupivacaine has been developed to provide up to 72 hours of local effects. This agent has been shown to be safe and to reduce postoperative pain in several different types of surgical procedures.32-34 The combination of these factors provides the patient with adequate pain control, while limiting side effects and complications, making outpatient TKA a reality. Blood Management Along with pain control, the possibility of blood loss can be another valid reason for skepticism about the safety of outpatient TKA. In most outpatient settings, resources

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for blood storage are not available, so it is important to identify any patients who may be at risk for postoperative transfusion. Medical screenings and preoperative blood work to evaluate hemoglobin level can be used to identify these patients. It has been shown that preoperative hemoglobin level is one of the greatest predictors of postoperative hemoglobin levels.35 A 2000 study showed if the hemoglobin level was higher than 13 g/dL, the transfusion rate approaches zero.36 Preoperative assessment and screening, along with other tools discussed later, may alleviate the anxiety regarding blood loss and the need for transfusions. Regional and hypotensive anesthesia is another intraoperative technique that can help decrease blood loss and the need for transfusion.37-40 Using regional anesthesia and maintaining the mean arterial pressure at less than 60 mm Hg has been found to decrease blood loss and keep the rate for postoperative transfusion exceedingly low.37-40 Another adjunct to decrease blood loss is the use of tranexamic acid. Tranexamic acid has most recently been used during arthroplasty to effectively minimize blood loss. Tranexamic acid reduces the rate of clot breakdown without increasing the rate of clot formation,41 which has been shown to decrease blood loss in several studies and substantially decrease the transfusion rate.42-46 Tranexamic acid can be administered intravenously, topically, or orally. All routes have been shown to effectively reduce blood loss and transfusion rates associated with arthroplasty.42-46 The intravenous and oral dosing typically administered is 1 g before incision and 1 g after surgery in the recovery room, but several methods of administration have been published. Topical solution is usually prepared by mixing 2 to 3 g of tranexamic acid in 50 to 100 mL of normal saline and placed in the wound at closure. Because blood is a well-known irritant and cause of pain, awareness of blood loss can limit any need for transfusion, as well as serve as a form of pain control. Surgical Approach The aim of any surgical procedure should be to complete all steps efficiently with the least amount of trauma to the patient. This is just as important when performing outpatient TKA. A minimally invasive approach is always an attractive option because the least amount of soft-tissue damage will allow a more rapid recovery. Several described methods have been described to gain access to the knee joint for TKA, and attention has been given to limiting damage to the quadriceps tendon. In some studies, these minimally invasive techniques have been shown to decrease pain and improve postoperative

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Chapter 19: Outpatient Total Knee Arthroplasty

function.47,48 However, other randomized controlled trials have reported no differences in the approach used.49,50 The surgeon should be comfortable with the approach chosen and must be diligent with the placement of retractors to avoid any aberrant cuts or damage to structures such as the medial collateral ligament, patellar tendon, or popliteal vessels.51 This will result in the most efficient surgery and best outcome for the patient. Efficiency trumps speed, and surgeons should make decisions and surround themselves with staff in the operating room to make the procedure run as smoothly as possible. The procedure should be a repeated choreographed set of steps that everyone involved knows and understands to limit errors, streamline the rapid recovery process, and make outpatient TKA as successful as possible. Postoperative Care and Management

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The immediate postoperative period can be separated into two distinct phases: the acute phase and the step-down phase. During the acute phase, the patient is transferred directly from the operating room and delivered to the postanesthesia unit. During this time, the patient must be stabilized medically while pain and nausea are managed. Experienced anesthesia and nursing staff are typically able to control pain and nausea using hydration and limited narcotics. The step-down phase begins after the patient is stabilized and comfortable and is transferred to a private recovery area. During this phase, family and friends are allowed to be with the patient. The patient is administered oral fluids and given a light snack, and will sit up in bed and then stand. The physical therapy staff teaches the patient proper use of ambulatory aides, and the patient will ambulate and attempt using the restroom. The goals for each patient are to ambulate safely and to be able to negotiate stairs. The physical therapy staff will also work with patients and family on activities of daily living after discharge. Deep vein thrombosis (DVT) prophylaxis is a major concern that should be addressed before surgery, but is reinforced before discharge. DVT prophylaxis should be based on a patient’s risk for this complication.52 The goal is to decrease the likelihood of DVT while minimizing postoperative bleeding. Most patients can be treated with compression stockings, ambulatory calf pumps, and aspirin. In high-risk patients, low–molecular-weight heparin

is recommended for 10 days followed by aspirin. Other oral agents such as warfarin and factor Xa inhibitors have also been used. After patients have met all goals and are ready for discharge, they are provided with instructions and materials to help at home. The nursing staff will review all medications prescribed, proper wound care, and all other discharge instructions, including follow-up in the surgeon’s office. How to proceed with outpatient physical therapy and rehabilitation is outlined. After the patients are discharged home they are contacted within 24 to 48 to assess their progress and to answer any questions. In this new age of outpatient TKA, surgeons must be certain they are still providing proper care for their patients without any undue risk of complications. Many studies have shown outcomes for outpatient arthroplasty to be successful.53,54 In one series, selected patients for outpatient TKA had low rates of complications or readmissions.1,2,53,54 However, outpatient arthroplasty is not something that should be attempted without preestablished protocols and multimodal approaches for proper patient care. The easiest way for surgeons to transition to outpatient TKA is by implementing rapid recovery protocols in their current practice, which will provide a safety net of traditional pathways to fall back on until the rapid recovery protocols are refined. By working diligently, surgeons will be able to progress to outpatient surgery. Summary TKA is one of the most successful and most common procedures performed by a practicing orthopaedic surgeon. As the paradigm shifts from inpatient to outpatient TKA, it is paramount that surgeons must work to ensure proper patient selection. This can be done with the help of medical and anesthesia personnel to identify the patient’s risks for complications. After patient selection, developing a system to educate patients about outpatient TKA should follow. Comprehensive multimodal pain management and blood conservation protocols must be set up to ensure that patients will be safe and comfortable after discharge from the hospital. Meticulous surgical techniques with minimally invasive approaches can also aid in performing outpatient TKA. Finally, appropriate postoperative care with physical therapy, DVT prophylaxis, and close follow-up will make outpatient TKA a reality.

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Key Study Points • Patient selection is perhaps the most important factor when considering outpatient TKA. Surgeons should be aware of any medical comorbidities and which ones cause the highest risk for complications or readmission. • Patients need to be educated at every step of the process for outpatient TKA. Staff, materials, and educational sessions outlining all aspects of the process should be readily available. • An extensive, complete pain management protocol for preemptive pain control that continues into the postoperative period should be created. • Limiting blood loss by using minimally invasive techniques and efficient surgical steps will help to avoid any complications. Adjuncts such as tranexamic acid and intraoperative hypotension also can be beneficial. • Postoperative patient care should be comprehensive and focused on pain control with early mobility. Protocols should be set for proper DVT prevention.

Annotated References

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1. Berger RA, Kusuma SK, Sanders SA, Thill ES, Sporer SM: The feasibility and perioperative complications of outpatient knee arthroplasty. Clin Orthop Relat Res 2009;467(6):1443-1449. Medline  DOI 2. Kolisek FR, McGrath MS, Jessup NM, Monesmith EA, Mont MA: Comparison of outpatient versus inpatient total knee arthroplasty. Clin Orthop Relat Res 2009;467(6):1438-1442. Medline  DOI 3. Teeny SM, York SC, Benson C, Perdue ST: Does shortened length of hospital stay affect total knee arthroplasty rehabilitation outcomes? J Arthroplasty 2005;20 (7 suppl 3):39-45. Medline  DOI 4. Isaac D, Falode T, Liu P, I’Anson H, Dillow K, Gill P: Accelerated rehabilitation after total knee replacement. Knee 2005;12(5):346-350. Medline  DOI 5. Cleary PD, Greenfield S, Mulley AG, et al: Variations in length of stay and outcomes for six medical and surgical conditions in Massachusetts and California. JAMA 1991;266(1):73-79. Medline  DOI 6. Kim S, Losina E, Solomon DH, Wright J, Katz JN: Effectiveness of clinical pathways for total knee and total hip arthroplasty: Literature review. J Arthroplasty 2003;18(1):69-74. Medline  DOI 7. Mabrey JD, Toohey JS, Armstrong DA, Lavery L, Wammack LA: Clinical pathway management of total knee

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arthroplasty. Clin Orthop Relat Res 1997;345:125-133. Medline 8. Pearson S, Moraw I, Maddern GJ: Clinical pathway management of total knee arthroplasty: A retrospective comparative study. Aust N Z J Surg 2000;70(5):351-354. Medline  DOI 9. Courtland LG: Same-day outpatient TJR gains popularity, but careful considerations must be made. Orthopedics Today 2015. Available at: http://www.healio. com/orthopedics/total-joint-reconstruction/news/print/ orthopedics-today/%7B275b9278-29aa-4c1f-b090101b38b03493%7D/same-day-outpatient-tjr-gains-popularity-but-careful-considerations-must-be-made. Accessed March 22, 2016. This article of surgeon’s experiences with outpatient arthroplasty reports on proper patient selection and a multimodal approach to pain control, which are key points that need to be discussed. Advocates for and against outpatient arthroplasty are represented and indicate that patient care and safety should be top priority. 10. Meding JB, Klay M, Healy A, Ritter MA, Keating EM, Berend ME: The prescreening history and physical in elective total joint arthroplasty. J Arthroplasty 2007;22 (6 suppl 2):21-23. Medline  DOI 11. Courtney PM, Rozell JC, Melnic CM, Lee GC: Who should not undergo short stay hip and knee arthroplasty? risk factors associated with major medical complications following primary total joint arthroplasty. J Arthroplasty 2015;30(9 suppl):1-4. Medline  DOI This study is a retrospective review of 1,012 patients who underwent both total knee and total hip arthroplasty to identify postoperative complications: 70 complications (6.9%) were reported, with 84% of these complications occurring after 24 hours. Chronic obstructive pulmonary disease, congestive heart failure, coronary artery disease, and cirrhosis were identified as the most common diseases to increase risk of developing complications. 12. Centers for Medicare and Medicaid Services: Am bulatory Surgical Center Payment – Proposed Rule, CMS-1633-P, 2016 Available at: https://www.cms. gov/Medicare/Medicare-Fee-for-Service-Payment/ ASCPayment/ASC-Regulations-and-Notices-Items/ CMS-1633 13. Berend KR, Lombardi AV Jr, Mallory TH: Rapid recovery protocol for peri-operative care of total hip and total knee arthroplasty patients. Surg Technol Int 2004;13:239-247. Medline 14. Lombardi AV Jr, Viacava AJ, Berend KR: Rapid recovery protocols and minimally invasive surgery help achieve high knee flexion. Clin Orthop Relat Res 2006;452(452):117122. Medline  DOI 15. Lombardi AV, Berend KR, Adams JB: A rapid recovery program: Early home and pain free. Orthopedics 2010;33(9):656. Medline

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This study reported that rapid recovery programs help patients recover faster, safer, and with few complications. Patient selection, efficient minimally invasive techniques, use of peripheral and local anesthesia, and early and aggressive rehabilitation were highlighted. 16. Dowsey MM, Kilgour ML, Santamaria NM, Choong PF: Clinical pathways in hip and knee arthroplasty: A prospective randomised controlled study. Med J Aust 1999;170(2):59-62. Medline 17. Berger RA, Sanders SA, Thill ES, Sporer SM, Della Valle C: Newer anesthesia and rehabilitation protocols enable outpatient hip replacement in selected patients. Clin Orthop Relat Res 2009;467(6):1424-1430. Medline  DOI

24. Buvanendran A, Kroin JS, Della Valle CJ, Kari M, Moric M, Tuman KJ: Perioperative oral pregabalin reduces chronic pain after total knee arthroplasty: A prospective, randomized, controlled trial. Anesth Analg 2010;110(1):199-207. Medline  DOI In this randomized placebo-controlled double-blinded study of pregabalin to decrease chronic neuropathic pain after TKA, 240 patients comprised two groups: one was given pregabalin, and the other was given a placebo. The incidence of neuropathic pain was less in the pregabalin group with increased flexion. These advantages of pregabalin came at the cost of increased early postoperative sedation and confusion.

19. Carmichael NM, Katz J, Clarke H, et al: An intensive perioperative regimen of pregabalin and celecoxib reduces pain and improves physical function scores six weeks after total hip arthroplasty: A prospective randomized controlled trial. Pain Res Manag 2013;18(3):127-132. Medline  DOI

This prospective, controlled study of patients undergoing TKA compared preemptive multimodal analgesia with and without the addition of femoral nerve blocks in 39 patients. No differences were found in patient-recorded outcome, except for quadriceps motor blockage on patients receiving femoral nerve blocks.

This randomized double-blind placebo-controlled pilot study reported on two groups. Group 1 was given pregabalin and celecoxib; group 2 was given a placebo. Results showed improved pain control and function with use of pregabalin and celecoxib.

26. Lovald ST, Ong KL, Lau EC, Joshi GP, Kurtz SM, Malkani AL: Readmission and complications for catheter and injection femoral nerve block administration after total knee arthroplasty in the Medicare population. J Arthroplasty 2015;30(12):2076-2081. Medline  DOI

20. Mears DC, Mears SC, Chelly JE, Dai F, Vulakovich KL: THA with a minimally invasive technique, multi-modal anesthesia, and home rehabilitation: Factors associated with early discharge? Clin Orthop Relat Res 2009;467(6):1412-1417. Medline  DOI

This study examined femoral nerve blocks used in the Medicare population between 2003 and 2011. It was hypothesized that patients receiving femoral nerve blocks would have lower risk of readmission but higher risk for falls, which was found to be true.

21. Sculco PK, Pagnano MW: Perioperative solutions for rapid recovery joint arthroplasty: Get ahead and stay ahead. J Arthroplasty 2015;30(4):518-520. Medline  DOI

27. Sharma S, Iorio R, Specht LM, Davies-Lepie S, Healy WL: Complications of femoral nerve block for total knee arthroplasty. Clin Orthop Relat Res 2010;468(1):135-140. Medline  DOI

This article stresses the need for patients to get ahead and stay ahead of four impediments to early rehabilitation and discharge: volume depletion, blood loss, pain, and nausea. Hydration, tranexamic acid, adequate anesthesia, and limited narcotics were used to get ahead and stay ahead for rapid recovery after joint arthroplasties. 22. Woolf CJ, Chong MS: Preemptive analgesia—treating postoperative pain by preventing the establishment of central sensitization. Anesth Analg 1993;77(2):362-379. Medline  DOI 23. Vadivelu N, Mitra S, Schermer E, Kodumudi V, Kaye AD, Urman RD: Preventive analgesia for postoperative pain control: A broader concept. Local Reg Anesth 2014;7: 17-22. Medline This report discusses how to decrease postoperative pain by using preventive and preemptive anesthesia. Using multimodal preoperative and postoperative analgesic therapies results in decreased postoperative pain and consumption of analgesics.

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18. Berend KR, Lombardi AV Jr: Liberal indications for minimally invasive oxford unicondylar arthroplasty provide rapid functional recovery and pain relief. Surg Technol Int 2007;16:193-197. Medline

25. Beaupre LA, Johnston DB, Dieleman S, Tsui B: Impact of a preemptive multimodal analgesia plus femoral nerve blockade protocol on rehabilitation, hospital length of stay, and postoperative analgesia after primary total knee arthroplasty: A controlled clinical pilot study. Scientific World Journal 2012;2012:273821. Medline  DOI

This study examined the complication rate of femoral nerve blocks for TKA in 1,018 procedures, with 709 femoral nerve blocks performed: 12 patients (1.6%) sustained a fall along with other adverse effects. It was recommended to modify protocols to account for quadriceps impairment after surgery. 28. Jaeger P, Nielsen ZJ, Henningsen MH, Hilsted KL, Mathiesen O, Dahl JB: Adductor canal block versus femoral nerve block and quadriceps strength: A randomized, double-blind, placebo-controlled, crossover study in healthy volunteers. Anesthesiology 2013;118(2):409-415. Medline  DOI This randomized double-blind placebo-controlled crossover study reported on 11 healthy young men receiving adductor canal blocks or femoral nerve blocks in one leg with placebo in the contralateral limb to measure quadriceps strength. Adductor canal blocks reduced quadriceps strength by 8%, and femoral nerve blocks reduced strength by 49%. Patients in the adductor canal group

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were better able to ambulate than those in the femoral nerve block group. 29. DeWeese FT, Akbari Z, Carline E: Pain control after knee arthroplasty: Intraarticular versus epidural anesthesia. Clin Orthop Relat Res 2001;392:226-231. Medline  DOI 30. Williams-Russo P, Sharrock NE, Haas SB, et al: Randomized trial of epidural versus general anesthesia: Outcomes after primary total knee replacement. Clin Orthop Relat Res 1996;331:199-208. Medline  DOI 31. Lombardi AV Jr, Berend KR, Mallory TH, Dodds KL, Adams JB: Soft tissue and intra-articular injection of bupivacaine, epinephrine, and morphine has a beneficial effect after total knee arthroplasty. Clin Orthop Relat Res 2004;428:125-130. Medline  DOI 32. Golf M, Daniels SE, Onel E: A phase 3, randomized, placebo-controlled trial of DepoFoam® bupivacaine (extended-release bupivacaine local analgesic) in bunionectomy. Adv Ther 2011;28(9):776-788. Medline  DOI In this multicenter, randomized double-blind phase III clinical study on the use of bupivacaine for local injection during bunionectomy compared with placebo, 193 patients were enrolled and their postoperative pain score was assessed. Patients receiving bupivacaine had decreased pain and decreased opioid use after surgery compared with the placebo group.

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33. Cohen SM: Extended pain relief trial utilizing infiltration of Exparel(®), a long-acting multivesicular liposome formulation of bupivacaine: A Phase IV health economic trial in adult patients undergoing open colectomy. J Pain Res 2012;5:567-572. Medline  DOI In this single-center, sequential-cohort study of 39 adults undergoing open colectomy, one group received ­patient-controlled analgesia with opioids and the other received multimodal analgesia and injection of liposomal bupivacaine. The group receiving liposomal bupivacaine required fewer opioids postoperatively, while resulting in lower costs and decreased length of stay compared with the opioid-based regimen. 34. Marcet JE, Nfonsam VN, Larach S: An extended pain relief trial utilizing the infiltration of a long-acting multivesicular liposome formulation of bupivacaine, EXPAREL (IMPROVE): A Phase IV health economic trial in adult patients undergoing ileostomy reversal. J Pain Res 2013;6:549-555. Medline  DOI In this open-label, multicenter, sequential cohort study, 27 patients underwent ileostomy reversal and had either standard intravenous patient-controlled analgesia opioid therapy or multimodal analgesia with injection of liposome bupivacaine. The use of liposome bupivacaine reduced opioid consumption, length of stay, and inpatient costs when compared with intravenous patient-controlled analgesia opioid regimen.

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35. Rosencher N, Kerkkamp HE, Macheras G, et al; OSTHEO Investigation: Orthopedic Surgery Transfusion Hemoglobin European Overview (OSTHEO) study: Blood management in elective knee and hip arthroplasty in Europe. Transfusion 2003;43(4):459-469. Medline  DOI 36. Hatzidakis AM, Mendlick RM, McKillip T, Reddy RL, Garvin KL: Preoperative autologous donation for total joint arthroplasty. An analysis of risk factors for allogenic transfusion. J Bone Joint Surg Am 2000;82(1):89-100. Medline 37. Sharrock NE, Salvati EA: Hypotensive epidural anesthesia for total hip arthroplasty: A review. Acta Orthop Scand 1996;67(1):91-107. Medline  DOI 38. Eroglu A, Uzunlar H, Erciyes N: Comparison of hypotensive epidural anesthesia and hypotensive total intravenous anesthesia on intraoperative blood loss during total hip replacement. J Clin Anesth 2005;17(6):420-425. Medline  DOI 39. Park JH, Rasouli MR, Mortazavi SM, Tokarski AT, Maltenfort MG, Parvizi J: Predictors of perioperative blood loss in total joint arthroplasty. J Bone Joint Surg Am 2013;95(19):1777-1783. Medline  DOI This study identified any clinical predictors for perioperative blood loss and allogenic blood transfusion in 11,373 patients reviewed from 2000 to 2008 who underwent either total hip or total knee arthroplasty. Multiple risk factors were identified and can be used to implement blood-conserving pathways. 40. Juelsgaard P, Larsen UT, Sørensen JV, Madsen F, Søballe K: Hypotensive epidural anesthesia in total knee replacement without tourniquet: Reduced blood loss and transfusion. Reg Anesth Pain Med 2001;26(2):105-110. Medline 41. Duncan CM, Gillette BP, Jacob AK, Sierra RJ, Sanchez-Sotelo J, Smith HM: Venous thromboembolism and mortality associated with tranexamic acid use during total hip and knee arthroplasty. J Arthroplasty 2015;30(2):272-276. Medline  DOI This large, single-center retrospective review reported on 13,262 total hip or knee arthroplasties for which tranexamic acid was used. The likelihood of venothromboembolism or death was not significant with tranexamic acid administration. 42. Wind TC, Barfield WR, Moskal JT: The effect of tranexamic acid on transfusion rate in primary total hip arthroplasty. J Arthroplasty 2014;29(2):387-389. Medline  DOI This retrospective review reported on 1,595 total hip arthroplasties that used tranexamic acid applied intravenously, topically, or neither to examine the need for transfusion after surgery. Intravenous tranexamic acid significantly reduced the need for transfusion; topical tranexamic acid did not reach significance. The occurrence of transfusion was 19.86% without tranexamic acid,

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Chapter 19: Outpatient Total Knee Arthroplasty

4.39% with intravenous tranexamic acid, and 12.86% with topical tranexamic acid. 43. Konig G, Hamlin BR, Waters JH: Topical tranexamic acid reduces blood loss and transfusion rates in total hip and total knee arthroplasty. J Arthroplasty 2013;28(9): 1473-1476. Medline  DOI This study examined 290 patients who underwent either total hip arthroplasty or TKA performed by a single surgeon to determine if topical tranexamic acid would decrease bleeding and transfusion postoperatively. Topical tranexamic acid significantly reduced postoperative bleeding and transfusion. 44. Gilbody J, Dhotar HS, Perruccio AV, Davey JR: Topical tranexamic acid reduces transfusion rates in total hip and knee arthroplasty. J Arthroplasty 2014;29(4):681-684. Medline  DOI This retrospective review reported on 155 patients undergoing total hip and knee arthroplasty while receiving topical tranexamic acid and 149 patients who did not. Significant reduction in blood loss, hemoglobin loss, and length of stay were reported with the use of topical tranexamic acid. 45. Alshryda S, Sarda P, Sukeik M, Nargol A, Blenkinsopp J, Mason JM: Tranexamic acid in total knee replacement: A systematic review and meta-analysis. J Bone Joint Surg Br 2011;93(12):1577-1585. Medline  DOI This meta-analysis of randomized controlled trials evaluated the effectiveness of tranexamic acid in 19 studies. Tranexamic acid showed significant reduction in blood loss and transfusion while not increasing DVT or pulmonary embolism.

This retrospective study compared the safety and efficacy of oral (302 patients) and intravenous (2,698 patients) tranexamic acid. When adjusted, oral tranexamic acid showed decreased rates of transfusion compared with intravenous administration. There is also a financial benefit of oral compared with intravenous tranexamic acid. 47. Liu HW, Gu WD, Xu NW, Sun JY: Surgical approaches in total knee arthroplasty: A meta-analysis comparing the midvastus and subvastus to the medial peripatellar approach. J Arthroplasty 2014;29(12):2298-2304. Medline  DOI This meta-analysis reported on 32 randomized controlled trials of 2,451 TKAs in 2,129 patients. When compared with the medial parapatellar approach, the midvastus approach showed better pain and range of motion at 1 to 2 weeks postoperatively, but with longer surgical time. The subvastus approach showed better range of motion 1 week postoperatively as well as straight leg raise and lateral retinacular release.

© 2017 American Academy of Orthopaedic Surgeons

This retrospective review reported on 801 patients undergoing TKA using either the standard parapatellar approach or a subvastus approach to evaluate the incidence of contracture. No difference was reported in operating room time, blood loss, body mass index, or length of stay. The manipulation rate was 4% for the standard parapatellar approach and 2% for the subvastus approach. 49. Guy SP, Farndon MA, Conroy JL, Bennett C, Grainger AJ, London NJ: A prospective randomised study of minimally invasive midvastus total knee arthroplasty compared with standard total knee arthroplasty. Knee 2012;19(6): 866-871. Medline  DOI This randomized controlled trial reported on 80 patients undergoing either a mini-midvastus approach or a medial parapatellar approach. No statistical differences were found in any parameters measured apart from blood loss and scar length. The mini-midvastus approach does not appear to provide any benefit aside from a smaller scar. 50. Tomek IM, Kantor SR, Cori LA, et al: Early patient outcomes after primary total knee arthroplasty with quadriceps-sparing subvastus and medial parapatellar techniques: A randomized, double-blind clinical trial. J Bone Joint Surg Am 2014;96(11):907-915. Medline  DOI This prospective double-blinded study of 129 patients undergoing TKA compared the quadriceps-sparing approach with the medial parapatellar approach. The quadriceps-sparing approach showed lower pain at rest and during activity, but showed no early functional advantage or decrease in opioid consumption when compared with the medial parapatellar approach.

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46. Irwin A, Khan SK, Jameson SS, Tate RC, Copeland C, Reed MR: Oral versus intravenous tranexamic acid in enhanced-recovery primary total hip and knee replacement: Results of 3000 procedures. Bone Joint J 2013;95B(11):1556-1561. Medline  DOI

48. Curtin B, Yakkanti M, Malkani A: Postoperative pain and contracture following total knee arthroplasty comparing parapatellar and subvastus approaches. J Arthroplasty 2014;29(1):33-36. Medline  DOI

51. Berend KR, Lombardi AV Jr: Avoiding the potential pitfalls of minimally invasive total knee surgery. Orthopedics 2005;28(11):1326-1330. Medline 52. Jacobs JJ, Mont MA, Bozic KJ, et al: American Academy of Orthopaedic Surgeons clinical practice guideline on: Preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty. J Bone Joint Surg Am 2012;94(8):746-747. Medline  DOI Ten recommendations are provided on the practice of preventing DVT in patients undergoing total hip arthroplasties and TKAs. Recommendations are given by grade of recommendation. 53. Berger RA, Sanders S, Gerlinger T, Della Valle C, Jacobs JJ, Rosenberg AG: Outpatient total knee arthroplasty with a minimally invasive technique. J Arthroplasty 2005;20(7 suppl 3):33-38. Medline  DOI 54. Berger RA, Sanders S, D’Ambrogio E, et al: Minimally invasive quadriceps-sparing TKA: Results of a comprehensive pathway for outpatient TKA. J Knee Surg 2006;19(2):145-148. Medline

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Chapter 20

Complications of Knee Arthroplasty Viktor E. Krebs, MD  Arthur L. Malkani, MD  Slif D. Ulrich, MD  David Backstein, MD, MEd, FRCSC  Mansour Abolghasemian, MD  Bryan D. Springer, MD  Christopher Samujh, MD

Abstract

Keywords: total knee arthroplasty, complications, periprosthetic infections, periprosthetic knee fractures, polyethylene wear

Introduction Complications after knee arthroplasty, although infrequent, interfere with the recovery and optimal function of the joint. Improved surgical training, instrumentation, and advanced implants have improved outcomes and decreased the unfavorable issues encountered in the past. Although general perioperative complications related to medical comorbidities and anesthesia can and do occur, these are typically evaluated and expertly co-managed

© 2017 American Academy of Orthopaedic Surgeons

Periprosthetic Knee Fractures Mansour Abolghasemi, MD; Viktor E. Krebs, MD; David Backstein, MD, MEd, FRCSC

Periprosthetic fractures can be a debilitating complication of knee arthroplasty and can result in extremely poor joint function and pain. This complication is a steadily increasing cause for revision surgery as noted in national registries and large database-derived publications.1,2 The incidence after primary knee a­ rthroplasty is r­ eportedly 2.5% to 38.0% after revision surgery3,4 (Table 1). In general, periprosthetic fracture rates have increased in proportion to the increased number of TKAs being performed because of expanded indications, obesity, increased survival of the implants, and the aging society. Although the percentages do not comprise most of the knee revisions being performed, the numbers and consequences are substantial, at an estimated occurrence of 15,000 procedures per year in the United States.5 Periprosthetic fracture treatment after knee arthroplasty can be extremely challenging for the patient and surgeon because of its unplanned and emergent nature; complication rates up to 40% have been reported, as well as revision rates of up to 29%, and a 1-year mortality rate that ranges from 4.6% to 13.0%.6

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Total knee arthroplasty (TKA) has been one of the most beneficial surgical procedures in the history of medicine, with survival rates reported at more than 90% in patients followed up to 20 years. Despite outstanding results, the complication risk associated with TKA can have an extremely negative effect on patients, surgeons, and the healthcare economy. The rare complications are being closely scrutinized and monitored due to the Comprehensive Care for Joint Replacement program in the United States, bundled payments, and similar quality- and cost-containment initiatives. Given the needs of an aging population, TKA has become a standardized treatment. Governments, corporations, institutions, and individuals expect all TKAs to occur without any initial problems, to allow function at a high level within months, and to last indefinitely. It is helpful for surgeons to define modifiable patient risk factors, provide concepts for continuous practice improvement, and outline successful methods for decreasing complications and improving measured outcomes.

by consultant partners. Currently, the most frequent, researched, and potentially difficult complications an orthopaedic surgeon can work to prevent and manage after total knee arthroplasty (TKA) include periprosthetic fractures, surgical site and deep periprosthetic infections, and the sequelae of long-term polyethylene wear. It is important to be knowledgeable about the most up-to-date research and currently accepted guidelines for the assessment, diagnosis, and management of these complications.

Epidemiology and Risk Factors In addition to poor outcomes, the socioeconomic consequences of periprosthetic knee fracture are considerable. According to projections by one study, by 2030 the

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Table 1

Periprosthetic Fracture Rates After Total Knee Arthroplasty Fracture Type and Location

Primary TKA (range)

Revision TKA (range)

Femur

0.1%–0.4%

0.8%

Tibia

0.07%–0.67%

0.36%–0.8%

Patella

Not reported

0.2%

Femur

0.3%–5.5%

0.3%–38%

Tibia

0.39%–0.4%

0.48%–0.9%

Patella

0.61%–1.19%

0.15%–2%

Intraoperative

Postoperative

TKA = total knee arthroplasty. Data from Schütz M, Perka C: Periprosthetic Fracture Management. New York, Thieme, 2013, pp 782-795.

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demand for primary TKA is expected to increase by 673% to 3.48 million procedures per year, with a subsequent increase of revisions of 601%. This equates to more than 80,000 periprosthetic knee fractures requiring emergent treatment every year. Costs have been estimated per occurrence for periprosthetic hip fractures to be between $20,000 to $200,000, and are likely similar for knees.7 Periprosthetic infection and fracture were associated with the greatest length of stay and costs for revision TKA.8 Bundled payments and pay-for-­performance programs will shift these cost burdens to hospitals and physicians, increasing the pressures on the already-­diminishing orthopaedic surgeon population. Appropriate care for patients with periprosthetic fractures will only be sustainable by organizing regional centers with adult reconstruction and trauma-trained orthopaedic surgeon teams to manage these volumes efficiently.6

Risk factors for periprosthetic knee fractures can be patient- and/or procedure-related9 (Table 2). Some patient factors are modifiable and should be evaluated ­diligently and optimized before performing elective TKA. In situations in which nonmodifiable patient-related risk factors predict short-term fracture complications, surgeons should counsel patients and families to consider continuation of nonsurgical management to avoid the known morbidity and mortality. Unfortunately, many of the risk factors for periprosthetic knee fracture evolve long after the primary procedure has been performed. The most difficult fractures to treat occur following minor trauma and falls in frail patients, often those with loose or failing implants. Periprosthetic knee fractures from higher-energy trauma tend to occur in more active patients with functioning implants; these are often amenable to treatment with standard fracture fixation techniques.

Dr. Krebs or an immediate family member has received royalties from Stryker; is a member of a speakers’ bureau or has made paid presentations on behalf of Stryker; and serves as a paid consultant to Stryker. Dr. Malkani or an immediate family member has received royalties from Stryker; is a member of a speakers’ bureau or has made paid presentations on behalf of Stryker; serves as a paid consultant to Stryker Orthopaedics; and serves as a board member, owner, officer, or committee member of the American Academy of Orthopaedic Surgeons. Dr. Backstein or an immediate family member has received royalties from Microport Orthopaedics; is a member of a speakers’ bureau or has made paid presentations on behalf of Microport Orthopaedics and Zimmer; serves as a paid consultant to Microport Orthopaedics and Zimmer; has stock or stock options held in Intellijoin Orthopaedics; and has received research or institutional support from Zimmer. Dr. Springer or an immediate family member has received royalties from Stryker; serves as a paid consultant to or is an employee of Convatec and Stryker; has received nonincome support (such as equipment or services), commercially derived honoraria, or other non–research-related funding (such as paid travel) from Joint Purification Systems; and serves as a board member, owner, officer, or committee member of the American Joint Replacement Registry and the Knee Society. None of the following authors or any immediate family member has received anything of value from or has stock or stock options held in a commercial company or institution related directly or indirectly to the subject of this chapter: Dr. Ulrich, Dr. Abolghasemian, and Dr. Samujh.

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Chapter 20: Complications of Knee Arthroplasty

Table 2

Risk Factors for Periprosthetic Fracture Patient-Related (Intrinsic)

Procedure/Implant-­ Related (Extrinsic)

Osteoporosis: reduced bone mineral density

Plate and hardware removal

Inflammatory arthritis

Previous osteotomy

Advanced age

Anterior notching of the femoral cortex

Female sex

Central box preparation for stabilized implants

Body mass index

Implant malalignment

Multiple comorbid medical conditions

Instability

Chronic steroid usage

Rotationally constrained implants

Malnutrition

Poor knee motion

Neuromuscular disorders

Manipulation

Dementia

Revision procedures Osteolysis Stress shielding Loose implants

© 2017 American Academy of Orthopaedic Surgeons

Classification and Planning Classification systems should provide a way to communicate clinically, guide treatment, offer a prognosis, predict complications, and permit the meaningful comparison of outcomes among different surgeons and centers. Knee periprosthetic fracture classifications have evolved since the early supracondylar fracture classification system was proposed in 1967. Classification systems have focused on a specific anatomic region: distal femoral/supracondylar, proximal tibial, and patellar. Each new classification has added to the previous with more detail focused on fracture pattern, site, distance from the prosthesis, chronology, bone quality, prosthetic fixation stability/ condition, fixation recommendations, and outcomes of treatment. Most have followed the principles of the proximal femoral periprosthetic Vancouver fracture classification. The most used and cited current classifications are the Rorabeck and Su classifications for distal femoral/ supracondylar fractures, the Felix classification for tibial fractures, and the Ortiguera and Berry classification for patellar fractures. The AO Foundation published a comprehensive book that includes a Unified Classification System (UCS) for all periprosthetic fractures.12 The UCS, based on the core principles of fracture location, component fixation, and bone strength/stock, which are pertinent to any joint during or after an arthroplasty procedure, was codeveloped by experts in arthroplasty and orthopaedic traumatology to modernize the principles of periprosthetic fracture management. The UCS builds on all previous classifications, expands them where needed, and combines their principles to deliver a refined system. Although seemingly more complex and detailed than previous classifications, the UCS is very straightforward, clinically applicable, and more detailed when needed for databases and registries. The UCS has substantial interobserver reliability and near-perfect intraobserver reliability when used for periprosthetic fractures in association with knee arthroplasties in the hands of experienced and inexperienced users.13

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Procedure-related risk factors can occur intraoperatively or any time after the procedure. The incidence of intraoperative knee fracture has been reported at less than 1% in primary and revision procedures10 (Table 1). These fractures occur during exposure, bone preparation, implant trialing, or final implantation. Intraoperative vigilance, judicious use of force when inserting implants, and meticulous technique may reduce fracture complications both intraoperatively and postoperatively. The most problematic fractures occur in poor-quality distal femoral bone at the implant-bone interfaces. When fractures occur during the acute postoperative 90-day recovery period, they are generally the result of unrecognized intraoperative fractures, falls, or aggressive therapy in deconditioned patients. Anterior distal femoral notching, especially that greater than 3 mm with sharp corners located exactly at the proximal end of the prosthesis, is a likely cause; biomechanical cadaver studies and finite-element models clearly show increased local stress concentration reducing torsional bone strength by 30% to 40%, and flexural strength by 18%. These observations have been disputed by clinical data that have not proven a statistical association between notching and fracture, conceivably due to the low incidence and a lack of statistical power in the

studies. Clinical data from a series of 36 periprosthetic supracondylar femoral fractures showed that 25% of the cohort had radiographically diagnosed notching of the anterior femoral cortex.11 The association between notching as a stress riser and predisposition to periprosthetic distal femoral fractures was strengthened by data that demonstrated a significant temporal association with the arthroplasty procedure (37.5 months notched versus 80.3 months), and a significant reduction in the fracture origin distance (3.2 mm notched versus 39.0 mm) from the anterior flange on the femoral component.11

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Table 3

AO/Unified Classification System Periprosthetic Fracture Classification V Knee

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Type

V.3

V.4

V.34

Femur, distal

Tibia, proximal

Patella

A Apophyseal or extraarticular/ periarticular

A1 Avulsion of

Lateral epicondyle

Medial or lateral plateau, nondisplaced

Disrupted extensor, proximal pole

A2 Avulsion of

Medial epicondyle

Tibial tubercle

Disrupted extensor, distal pole

B Bed of the implant or around the implant

B1 Prosthesis stable, good bone

Proximal to stable stem, good bone

Stem and component stable, good bone

Intact extensor, implant stable, good bone

B2 Prosthesis loose, good bone

Proximal to loose stem, good bone

Loose component/ stem, good bone

Loose implant, good bone

B3 Prosthesis loose, poor bone or bone defect

Proximal to loose stem, poor bone, defect

Loose component/ stem, poor bone, defect

Loose implant, poor bone, defect

C Clear of or distant to the implant

-

Proximal to the implant and cement mantle

Distal to the implant and cement mantle

-

D Dividing the bone between two implants or inter­ prosthetic or inter­ calary

-

Between hip and knee arthroplasties, close to knee

Between ankle and knee arthroplasties, close to knee

Between ankle and knee arthroplasties, close to knee

E Each of two bones supporting one arthroplasty or poly­peri­ prosthetic

-

Femur and tibia/patella

F Facing and articulating with a hemi­ arthroplasty

-

Fracture of femoral condyle articulating with tibial hemiarthroplasty

-

Fracture of the patella that has no surface replacement and articulates with the femoral component of the total knee arthroplasty

Data from Duncan CP, Haddad FS: The Unified Classification System (UCS): Improving our understanding of periprosthetic fractures. Bone Joint J B 2014;96(6):713-716.

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Chapter 20: Complications of Knee Arthroplasty

Classification is initially based on a plain radiographic diagnosis. Whole-femur views should be available from the hip to the knee; CT is recommended to further delineate the extent and location of the fracture, to assess the bone stock quality, and to evaluate for osteolysis and loosening. The primary purpose of periprosthetic knee fracture classification is to differentiate those that can be fixed with osteosynthesis from those that require revision or segmental replacement.12 When planning treatment, the critical issues are implant fixation and bone quality, factors that are classified as UCS type B12 (Table 3). The distinction between loose and well-fixed implants is not always clear, and studies have shown that a high number of periprosthetic fractures classified as stable implants are actually found to be loose implants at the time of surgery. The possibility of infection should be routinely evaluated using inflammatory markers.9 In addition, classification does not address soft-tissue, tendon, or ligament integrity. For these reasons, classifications are considered as guides and not rigid decision algorithms. Surgeons treating periprosthetic knee fractures must understand and be prepared to adapt to multiple fixation and reconstruction alternatives.

© 2017 American Academy of Orthopaedic Surgeons

Distal Femoral Fracture Distal femoral fracture, the most common periprosthetic knee fracture, may be difficult to treat because of the magnitude of deforming forces concentrated in the metaphysis and at the implant interfaces. These mostly occur adjacent to a well-fixed femoral component.16 The current consensus on treatment of the most common fracture type reported, stable implants with bone that will hold screws (AO/UCS V.3 B1 - Rorabeck type II), is to use internal fixation with periarticular locking plates or retrograde intramedullary nails.17-20 Several clinical and biomechanical studies have clearly shown the superiority of these two options over conventional plates.21 Knee implant design frequently determines the fixation method required; a closed posterior-stabilized box, presence of a stem, or a canal/notch mismatch preclude the use of intramedullary fixation. One study using a sawbone model created a table demonstrating the compatibility and technical feasibility of inserting commonly used retrograde nails through the 10 most frequently used femoral implants for primary TKA in the United Kingdom using the National Joint Registry.22 The study found that most are not compatible because of excessive force required for insertion, damage to the nail during insertion, posterior location of the entrance, and risk of anterior cortex perforation. One definite advantage of intramedullary fixation is that the implant is inserted through a midline knee incision, in contrast to plate fixation, which normally necessitates the addition of a lateral incision to the knee (with potential for soft-tissue complications). However, recent clinical publications report varied results and do not consistently favor one method over the other. A multicenter study of 36 retrospectively reviewed cases reported successful healing using three locked-plate designs in 28 patients (77.8%), with malunion in 5 patients (13.9%) and failure requiring arthroplasty in 3 (8.4%).11 Patients who underwent submuscular plate insertion, compared to those who had an extensive lateral approach, had a reduced nonunion risk (P = 0.05).22 Another study reported on 42 fractures proximal to posterior-stabilized TKAs; 24 were treated with periarticular locking plates and 18 with retrograde intramedullary nails.23 Nonunion was seen in 29.2% of patients (7 of 24) in the plating group, and failure occurred in 27.8% (5 of 18 patients) of the nail group (2 fractures at the level of the proximal nail tip and 3 nonunions). No difference was found in clinical results in those that healed.23 A multicenter study retrospectively reviewed 63 patients with Rorabeck type II fractures, 24 in which 35 patients were treated

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2: Knee

Treatment The management of periprosthetic fractures is complicated by several variables, which include osteopenic bone in the distal femoral metaphyseal region, short distal segments for adequate fixation, surgical exposure and blood loss, nonunion, malunion, and malalignment.14 Periprosthetic knee fractures that occur in patients with well-fixed, aligned, and stable joints can be treated using standard fracture fixation techniques when the arthroplasty hardware does not interfere with the abil­ity to achieve anatomic reduction and alignment. When this is not the situation, treatment requires a combined knowledge of the latest techniques and biomechanical principles of fracture fixation and revision arthro­plasty.1 Treatment complication and failure rates have been reported in up to a third of patients, an indication of the procedure technicality and the encumbered patient population that is typically affected.15 Individual patient prefracture function, comorbidities, and lifestyle goals should also be considered when deciding on the treatment method. Surgical treatment is indicated in most cases, but nonsurgical management can be acceptable when fractures are nondisplaced, implants are stable, anesthesia risks are high, and patients are nonambulatory. The choice of surgical intervention is best determined by the team on the basis of fracture characteristics as well as the capabilities of the surgeon and operating theater/hospital. Given the complexity of these reconstructions, transfer

to a surgeon with experience and a wide experience of surgical options is preferable.

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Section 2: Knee

Figure 1

AP (A) and lateral (B) radiographs demonstrate a distal femoral periprosthetic fracture sustained after arthroplasty performed for femoral supracondylar fracture in a 59-year-old woman. AP (C) and lateral (D) radiographs were obtained following revision arthroplasty with a locking plate. The implant components were well fixed.

2: Knee

with intramedullary femoral nailing and 28 with a locking screw plate. Radiographic union was significantly greater in the locking screw plate group, and the rate of revision surgery was only 14%, although it reached 40% in the intramedullary nail group.24 Another study compared modern retrograde intramedullary nails with a locked distal screw to periarticular locking plates in a retrospective consecutive series of 91 patients (29 nails, 66 plates) with 95 periprosthetic supracondylar femoral fractures. Follow-up of 85 knees showed that 83.5% went on to union at an average of 16 weeks:25 2 nonunions (9%) were reported in the intramedullary nail group and 12 nonunions/delayed unions (19%) were reported in the locking plate group (P = 0.34). A recent systematic literature review included 41 studies published from 2004 to 2014 and supported this consensus by showing that locking plates and intramedullary nail/rods have the highest healing rates (87% and 84%, respectively).20 Another systematic review pooling 719 cases found comparable union rates with locking plates or intramedullary nails, but the malunion rate was significantly higher with the use of nails.17 Some evidence also suggests better performance of polyaxial locking plates compared to monoaxial plates.2 When applying a locking plate, involvement of the far cortex by the locking screws decreases the screw cutout rate as well as the risk of varus displacement. However, it also potentiates the stiffness of the construct, which is not biologically favorable. Recently, the concept of far

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Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

cortical locking with a gliding proximal screw hole has been introduced in an attempt to decrease stiffness while retaining strength, and early results have been promising.15 Figure 1 shows a distal femoral periprosthetic fracture treated with internal fixation using a locking plate. Clinical outcomes of treated periprosthetic fractures are often poor. Range of motion was reduced in most of the patients treated with plating in one study, with the cohort averaging 101° of flexion (range 0° to 140°), and 65.7% required long-term ambulatory aid assistance.11 The 10-year systematic review reported complication rates of 35% for locking plates and 53% for intramedullary nailing.20 In addition, reported radiographic results are concerning. A total of 56% of intramedullary nails and 41% of locking plates fell outside of acceptable alignment at final radiographic follow up.25 In response to persistent failures, the addition of an intramedullary allograft to the plating technique has been reported. Recent biomechanical studies have addressed this issue. A finite-­element comparison study showed that the biomechanical performances of the nail and less invasive stabilization system (LISS) plate were comparable, but addition of an intramedullary allograft to a LISS plate significantly stabilized the fracture gap, reduced the implant stress, and was recommended as the preferred fixation method for periprosthetic distal femur fractures.26 These findings were refuted by another study evaluating the stability of four methods of fixation for supracondylar periprosthetic femur

© 2017 American Academy of Orthopaedic Surgeons

Chapter 20: Complications of Knee Arthroplasty

Figure 2

AP (A) and lateral (B) radiographs of a distal femoral fracture in an elderly patient following total knee arthroplasty. AP (C) and lateral (D) radiographs obtained distal femoral replacement performed to address poor distal bone stock.

© 2017 American Academy of Orthopaedic Surgeons

stock after removal of the old implant, a stemmed revision prosthesis can be used to address the loosening as well as to fix the fracture.9 The stem should press-fit and be long enough to bypass the fracture site by at least two femoral diameters.29 Current controversy exists when implant fixation is questionable, bone quality is poor, and patient demand is low. No consensus exists on the treatment of unstable fractures with bone that will not reliably hold screws (AO/UCS V.3 B2, V.3 B3: Rorabeck type III). The goal of fracture fixation is to reestablish preinjury function and a pain-free knee joint, with fracture union within 6 months, and to achieve the following parameters: range of motion, 0° to 90°; a maximum shortening of 2 cm; up to 5° of coronal varus/valgus malalignment, and up to 10° of sagittal plane deviation. These goals do not parallel those of primary or revision knee arthroplasty, and suggest that fractures may be better managed by other means. Treatment challenges arise from the typical distal fracture location and poor bone quality, the technical challenges associated with the femoral implant and varying designs, suboptimal bone biology, and the elderly patient population in which these fractures typically occur. Revision TKA with a stemmed prosthesis or a distal femoral arthroplasty is possibly a better option for many reasons. Although no randomized trials have been reported, multiple case-control studies have shown acceptable early results of distal femoral replacement in elderly, low-demand patients with poor bone quality, regardless of the femoral component fixation30-32 (Figure 2). When dealing with poor distal fragment bone stock in a relatively young patient, a composite distal

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

2: Knee

fractures.27 Composite femurs with a well-fixed cemented TKA femoral component underwent nondestructive tests to determine construct stiffness in axial and torsional cyclic loading followed by quasi-static axial loading until failure. They showed that the intramedullary fibular strut allograft with polyaxial locking plate did not prove to be significantly better than the polyaxial locking plate only.27 This discrepancy might be due to the biomechanical advantage of polyaxial plates over the fixed-angle locking system of the LISS plates, which could potentially obviate the need for additional strut graft. The devices have advanced over the past 10 years, and promising clinical results have been reported with polyaxial locking plates and intramedullary locking nails that allow the distal screws to be locked to the nail, creating a fixed-angle device.2,25,27,28 Further research and clinical follow-up is needed to ascertain if one type of fixation method is superior. The current preference is to use a modern retrograde nail with multiple distal locking screws when the femoral component is compatible with nailing and the fracture is sufficiently proximal to allow insertion of at least two locking screws to the distal segment. In cases not fulfilling these criteria but still suitable for fixation, the use of a polyaxial locking plate is preferred. The polyaxial design incorporates locking screws that have 15 degrees of freedom in all directions.2 In addition to the biomechanical advantage of nonparallel screws, this enables the surgeon to accommodate a maximum number of screws to the distal segment. When the femoral component is loose or malaligned, it should be revised. In the presence of adequate bone

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Section 2: Knee

A, AP radiograph obtained from a young patient demonstrates a severely comminuted fracture of the distal femur and loose components. AP (B) and lateral (C) radiographs were obtained following revision with a prosthesisallograft composite.

Figure 4

Algorithm for the management of distal femoral periprosthetic fracture.

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Figure 3

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Figure 5

AP (A) and lateral (B) radiographs demonstrate type 1B proximal tibial periprosthetic fracture. C, Lateral radiograph obtained following revision arthroplasty with a trabecular metal cone performed to address poor bone stock.

Tibial Fractures Relative to the femur, periprosthetic fractures of the tibia and patella are relatively uncommon (Table 1), and current

© 2017 American Academy of Orthopaedic Surgeons

reports presenting new data on treatment methods and outcomes are limited. Tibial fracture is the least common fracture around TKA, with a reported incidence of less than 1%.34 With the increasing number of TKA surgeries being done, tibial periprosthetic fractures are likely to be seen more frequently, and orthopaedic surgeons should be familiar with the principles of treatment. In contrast to supracondylar periprosthetic fractures, which frequently occur around a well-fixed component, tibial fractures are more often associated with a loose implant.35 Other risk factors include revision surgery and conditions compromising physical strength of the tibia, such as osteoporosis and osteolysis. Malalignment of the tibial component is also correlated with fracture of the tibial plateau.34 Treatment of tibial periprosthetic fractures has been most commonly reported based on the Felix classification system, which correlates with the AO/UCS V.4 A-D.12,13 The most common are V.4 B fractures, which involve the tibial plateau. For nondisplaced fractures with a stable implant, nonsurgical management with cast immobilization is acceptable. Most are not traumatic in origin, and many occur intraoperatively due to poor bone stock or osteolysis (V.4 B2-3 fractures). These are most common, and when associated with loosening, revision of the implant is required, which is often a complex procedure that requires advanced revision TKA techniques to deal with bone loss and instability (Figure 5). When the bone stock is solid and the implants remain

Orthopaedic Knowledge Update: Hip and Knee Reconstruction 5

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femoral allograft-prosthesis can be considered as an option32 (Figure 3). An algorithm for treating distal femoral periprosthetic fractures is shown in Figure 4. Knee periprosthetic fractures are associated with very high morbidity and mortality rates.6 Mortality rates can be as high as 17% at 6 months and 30% at 1 year.15 These fractures carry a much higher risk of mortality than do isolated distal femoral fractures or TKA, and are more aligned with the reported mortality rate of proximal femoral fractures in the elderly. An epidemiologic study found that when compared with patients admitted for other arthroplasty-related diagnoses, individuals admitted with periprosthetic fracture were more often admitted emergently/urgently, had longer hospital lengths of stay (only second to those with periprosthetic joint infection [PJI]), had higher rates of discharge to locations other than home, and had the highest level of mortality.6 In addition, reduced functional capability is a usual outcome.33 Postoperative mobility of patients with periprosthetic distal femoral fractures is reduced, with a large proportion of patients needing ambulatory aid assistance.33 Other common complications include reduced range of motion, extensor mechanism weakness, and infection and wound complications.

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Figure 6

Algorithm for the management of periprosthetic tibial fracture.

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well fixed (V.4 B1fracture), the fracture mechanism is usually traumatic and can be treated with internal plate fixation.36 Figure 6 shows an algorithm of a simplified approach to tibial fractures around TKA. Patellar Fracture Patellar fracture is the second most common periprosthetic fracture around the knee, with reported incidence rates of 0.12% to 3.90%. Resurfacing of the patella is considered a risk factor, and few AO/UCS V.34 F fractures of unresurfaced patellae have been reported. Another risk factor is lateral retinacular release, likely a result of vascular compromise of the patella. One study found that a history of a lateral release was present in 51% of all such cases. In addition, any condition that weakens the patella can be a risk factor, including osteoporosis, rheumatoid arthritis, corticosteroid use, overresection that leaves less than 10- to 15-mm patellar thickness, and use of implants with a large central peg. In addition, situations that increase patellar loads may increase the risk of fracture, including younger age, male sex, patellar underresection resulting in anterior overstuffing of the knee, use of posterior-stabilized (PS) prostheses, patellar maltracking, active lifestyle (including repetitive loaded knee flexion), and high knee range of motion.

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Most patellar fractures after TKA are asymptomatic. In a systematic review of 752 patellar periprosthetic fractures, one study reported that nearly 88% of cases were identified during routine follow-up. Another study found that significant trauma was not reported in more than 60% of cases. The most common objective finding was extensor lag of the knee. Treatment of patellar periprosthetic fracture has been most commonly reported on the basis of the Ortiguera and Berry classification system, which also correlates with the AO/ UCS. As reported in a systematic review, fractures with an intact extensor mechanism and loosening of the patellar component (AO/UCS V.34 B2-3 fractures) are the most common, and they comprise more than half of all periprosthetic patellar fractures. The least common are those with disruption of the extensor mechanism, with or without loosening of the implant (V.34 A or B fractures).37 Treatment should have a functional rather than an anatomic goal and should focus on restoration of the extensor mechanism to preserve knee function. Attempts at internal fixation of these fractures have been almost uniformly unsuccessful, with a reported nonunion rate of 92% after tension-band or cerclage wiring. This is in contrast to the accepted strategy of treating the native

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Figure 7

Algorithm for the management of periprosthetic patellar fracture (asterisk indicates patellar component is left alone if stable and resected or replaced if loose).

© 2017 American Academy of Orthopaedic Surgeons

extensor mechanism can be performed using synthetic mesh.41 An algorithm for treating patellar fracture after TKA is shown in Figure 7. Nonsurgical treatment should be considered for all painless cases with less than 10° of extension lag at the time of initial examination, regardless of the radiographic features.

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patella, in which anatomic reconstruction of the bone is usually possible. A general consensus exists for employing nonsurgical treatment of fractures with an intact extensor mechanism and a stable implant. Treatment with a cast or a brace until confirmed healing at the fracture site usually results in excellent outcomes with minimal residual extension lag.38,39 Surgical treatment is recommended for fractures with disruption of the extensor mechanism, with or without loosening of the implant (AO/UCS V.34 A or B fractures), and those with an intact extensor mechanism and loosening of the patellar component (AO/UCS V.34 B2B3 fractures). However, surgical treatment has a modest outcome and high complication rate. Restoration of the extensor mechanism may be accomplished using a partial or total patellectomy to avoid the high failure rate of fixation techniques, with the surgeon understanding the potential for a residual extension lag. Internal fixation may be performed in cases in which good bone stock and a good patellar blood supply are evident.40 In most cases in which patellar components are loose, reimplantation is not recommended. In the most extreme cases, in which extensor mechanism tissue is of poor quality and is not amenable to repair, an allograft of the knee extensor can be transplanted, or reconstruction of the

Interprosthetic Fracture Femoral fractures in the presence of ipsilateral knee and hip implants are rare, but they are on the rise, in tandem with the increasing population of multiarthroplasty patients. These fractures are classified as AO/UCS V.3-D; the incidence has been reported to be from as low as 0.4% for primary implants to up to 24% for revision prostheses.42 The same risk factors for periprosthetic hip and knee fractures also increase the risk of interprosthetic fracture.42 Appropriate treatment primarily depends on the stability of the components and the bone quality. Most fractures located between stable hip and knee implants can be fixed with a locking plate.42 Poor bone quality can be augmented with strut cortical allograft. Preferably, the plate should support the whole length of the femur, but a minimum requirement is involvement of 10 cortices distal to the fracture and bypassing the femoral stem by at least twice the diameter of the femur.42,43 Using a cerclage wire

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Figure 8

Algorithm for the management of interprosthetic fracture.

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at the upper end of the plate will decrease the load concentration, leading to less risk of future fracture.44 Polyaxial locking screws have outperformed monoaxial screws in reported studies.42,45 The minimally invasive technique of plate application is rewarded by higher union and lower complication rates.43 As a general rule, if the surgical site is opened adequately, the addition of autologous bone graft or bone morphogenetic protein materials may enhance the biology and healing.45 In the scenario of interprosthetic fracture, any loose implants should be revised. On occasion, the fracture can be stabilized by the stem of the revision components.45 Otherwise, a plate should be added to the construct following the criteria just described. If one or both of the old implants were revision implants, inadequate bone may remain for stabilization of the new implants in the broken bone. Conventional or intramedullary total femoral replacements are an option in this case. An algorithm for approaching interprosthetic fractures of the femur is shown in Figure 8. Acceptable results have been reported for internal fixation of interprosthetic fractures, with a union rate of approximately 90%.45 However, a decline in function and quality of life is a common outcome.46

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Periprosthetic Joint Infections Bryan D. Springer, MD; Viktor E. Krebs, MD

PJIs and surgical site infections (SSIs) after knee arthroplasties are exceedingly problematic and constitute costly complications for patients, surgeons, and healthcare systems. The orthopaedic community has put forth great efforts to control SSIs, and the rate of PJIs has decreased over the past decade. The elective nature of the procedures makes them challenging at every level, from diagnosis through (the usually prolonged) treatment. When surgical intervention is required for infection, it negatively affects a patient’s perception of the procedure and strains the doctor-patient relationship. The recent implementation of bundled payments and accountable care models has made the financial, physical, and emotional effects of this problem more deeply impactful on all involved. Despite the monumental efforts that have been put forth in orthopaedic surgery to eliminate infection, it is a complication of joint arthroplasty surgery that can be reduced but can never be completely eliminated. PJI Incidence and Risk With their detrimental repercussions, SSIs are estimated to occur in nearly 1 million patients annually in the

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Chapter 20: Complications of Knee Arthroplasty

Table 4

Table 5

Patient-Related Risk Factors for the Development of Periprosthetic Joint Infection

Risk Factors for the Development of Periprosthetic Joint Infection

Risk Factors

Surgical- and/or Procedure-Related (Extrinsic) Factors

Modifiable

Modifiable

Male sex

No

Obesity (body mass index greater than 35 kg/m2)

Yes

Prolonged surgical time greater than 2 hours

Yes

Inflammatory arthritis

No

Antibiotics prophylaxis greater than 24 hours

Yes

Use of antibiotic bone cement

Yes

Blood loss and transfusion

Yes

Diabetes/preoperative hyperglycemia (HbA1c is a poor predictor)

Yes/No

American Society of Anesthesiologists score greater than 3

No

Excessive wound drainage

Yes

Smoking/tobacco use

Yes

Wound healing problems

Yes

Pulmonary disease

No

Constrained and hinged prostheses

Chronic steroid medication use

No

Previous revision for infection

Osteonecrosis

No

Staphylococcus aureus/methicillinresistant S aureus colonization Posttraumatic arthritis Anemia/transfusion

Yes/No No Yes/No

Bacteremic events

No

Prior joint infection

No

Retained hardware

Yes/No

Malnutrition

Yes

© 2017 American Academy of Orthopaedic Surgeons

No

have been associated with an increase in PJI. The increased demand for TKA and the accompanying predicted future financial burden of PJI points to a need for better preoperative medical optimization and a possible shift in the indications for PJI in this high-risk population.50 The cumulative yearly expenditure from infection after total joint arthroplasty is expected to exceed $1.62 billion by 2020, with an estimated cost related to a single PJI being as high as $130,000.51,52 Modifiable intrinsic patient risk factors must be identified and addressed in a manner that is best for the individual. Nonmodifiable intrinsic risk factors should be managed or used to guide patients to appropriate nonsurgical management (Table 4). A study of 300 hip and knee arthroplasty cases revealed that only 20% of all cases and 7% of revision cases for infection had no modifiable risk factors. The most common risk factors were obesity (46%), anemia (29%), malnutrition (26%), and diabetes (20%). The high prevalence of several modifiable risk factors demonstrates that opportunities for perioperative optimization are many.53 Despite abundant reports in the literature, consensus has not been reached with regard to the efficacy of many preventive methods. In knee arthroplasty, use of a prehospital admission skin preparation protocol using 2% chlorhexidine gluconate (CHG) cloth was been shown to reduce PJI in a large single-­institution cohort of 3,717 patients having primary or revision procedures. This retrospective study demonstrated a 0.3% incidence of PJI in the CHG cloth group versus a 1.9% rate in the control group at 1 year.54 Another large retrospective study that included 2,055 TKA patients who used the CHG wipes an hour before the procedure did not show a statistically significant benefit, with PJI rates

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United States, and approximately 355,500 occur after orthopaedic procedures according to the National Nosocomial Infections Surveillance System. The current SSI rate after primary TKA is reported at 1.0% to 2.3%. PJI, a deep SSI as defined by the Centers for Disease Control and Prevention, is reported to occur in 0.5% to 1.8% of primary TKAs. PJI is most common the first 2 years after the index procedure, and the incidence between 2 and 10 years is 0.46% in the Medicare population.47 The incidence after revision knee arthroplasty is considerably higher and has been reported as high as 46%. One study recently reported much lower rates for 1,802 index knee revisions performed for aseptic reasons in 1,615 patients; the cumulative risk of infection at 1, 5, 10, and 20 years after index revision was 1.0%, 2.4%, 3.3%, and 5.6%, respectively.48 PJI itself is the most common reason for knee arthroplasty revision, reported in up to 25% of cases.49 PJI after primary and revision knee arthroplasty is also associated with tremendous morbidity, and its presence doubles the mortality risk. Risk factors for infection-related complications after knee arthroplasty have been the focus of numerous recent studies. Alone or in combination, many of these factors

Yes/No

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Table 6

Musculoskeletal Infection Society Definition of PJI According to the International Consensus Group PJI is present when 1 major criterion exists or 3 of 5 minor criteria exist

Major criteria Two positive periprosthetic cultures with phenotypically identical organisms Sinus tract communicating with the joint/implant Minor criteria Elevated serum C-reactive protein level and erythrocyte sedimentation rate Elevated synovial fluid white blood cell count or ++ change on leukocyte esterase test strip Elevated synovial fluid polymorphonuclear neutrophil percentage Positive histologic analysis of periprosthetic tissue Single positive culture from periprosthetic tissue or fluid PJI = periprosthetic joint infection. Adapted from Whitehouse MR, Mehendale S: Periprosthetic fractures around the knee: Current concepts and advances in management. Curr Rev Musculoskelet Med 2014;7(2):136-144.

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of 0.8% in those using wipes and 1.2% in those who did not.55 Unfortunately, attempts by health care institutions to improve a patient’s overall health and decrease the risks of complications such as PJI are often disregarded. A recent study showed that 78% of patients (3,716/ 4,751), regardless of age or sex, were noncompliant with simple preoperative disinfection protocols.56 Risk factor optimization requires patient participation and accountability, and the focus should be on improving patient education and comprehension at all levels to effectively reduce complications such as SSI and PJI. Extrinsic risk factors are attributable to the surgeon and hospital facility and must be always factored into the primary and revision knee arthroplasty procedure risk profile (Table 5). Most procedure-related risk factors can be managed with preoperative planning and the use of standardized procedural/clinical pathways. Preoperative blood management programs for anemia, intraoperative use of tranexamic acid, and techniques to minimize bleeding have been shown to decrease allogeneic blood transfusion and subsequent infection risk. Prolonged surgical time, as a proxy for the complexity of the surgical procedure, has been associated with a 9% increase in the risk of

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deep SSI for each 15-minute increase in procedure length (95% confidence interval [CI]: 4%-13%).57 Also, surgical times longer than 210 minutes showed an increased risk of infection in the Medicare population when compared to those less than 120 minutes.47 Wound healing problems should be addressed expediently and aggressively to prevent deep progression and implant involvement. The use of antibiotic bone cement to decrease the occurrence of PJI has been controversial. A 43,149 patient study from the Finnish Arthroplasty Register in 2009 showed fewer infections when antibiotics were administered, both intravenously and in the cement, for primary and revision knee arthroplasty. Another study of 1,625 patients in which antibiotic cement was used in half of the implants did not find a reduction in the prevalence of deep infection following TKA. Recently, a study reported on an analysis of 56,216 knees in which use of antibiotic-laden cement was associated with a paradoxical increase in the risk of infection; the effect was theorized to be a result of surgeon selection of high-risk patients. It was reported that the addition of antibiotics to the irrigation solution was protective against deep SSI, although the dosage, antibiotics, and technique were not specified.57 PJI Definition The definition of PJI was established by the Musculoskeletal Infection Society (MSIS) and was modified by the International Consensus group to standardize the criteria for the diagnosis of PJI15,58 (Table 6). The American Academy of Orthopaedic Surgeons (AAOS) clinical practice guideline on the diagnosis of periprosthetic joint infection also provides a standardized approach.59 Adoption is already apparent in the literature; both have improved research consistency and have contributed to updated evidence that has guided clinicians who evaluate and treat painful knee replacements. Recent updates further define the thresholds for the MSIS minor criteria58 (Table 7). The definition and guidelines are as dynamic as the PJI complication, and as evidence mounts, they will be further refined to incorporate new techniques and tests as they become available, validated, and shown to be cost effective. PJI Diagnosis When evaluating a painful knee arthroplasty, it is imperative that the diagnosis of infection be highly suspected, ruled out, or definitively established before proceeding with other treatment options. The diagnosis of PJI can be challenging, as most tests do not evaluate specifically for the presence of PJI, but rather are indirect measures. The history, physical examination, and clinician’s astuteness remain the foundation for inquiry and the basis for more

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Chapter 20: Complications of Knee Arthroplasty

Table 7

Threshold for the Musculoskeletal Infection Society Minor Diagnostic Criteria Criterion

Acute PJI (Before 90 Days)

Chronic PJI (After 90 Days)

Erythrocyte sedimentation rate (mm/h)

Not helpful; no threshold determined

30

100

10

10,000

3,000

90

80

Leukocyte esterase test strip

+ or ++

+ or ++

Histologic analysis of tissue

>5 Neutrophils per high-power field in 5 fields (×400)

Same as for acute PJI

C-reactive protein level (mg/L) Synovial white blood cell count (cells/μL) Synovial polymorphonuclear neutrophils (%)

PJI = periprosthetic joint infection.

© 2017 American Academy of Orthopaedic Surgeons

serologic parameters, and an initial negative aspiration based on cell counts, differential counts, and cultures. The International Consensus on PJI recognizes this population of patients and has declared that PJI may be present without meeting the criteria, specifically in the case of less-virulent organisms.58 If suspicion is high or prior cultures have been negative, the addition of acid-fast bacilli and fungal cultures should be considered during the initial or repeat aspiration. Additionally, incubating cultures for a longer duration (21 days) may assist in identifying fastidious organisms, such as Propionibacterium acnes, or strains of coagulase-negative staphylococci. Despite attempts to identify the infecting organism, cultures may remain negative in as many as 20% of cases in which there is true infection. The use of synovial fluid biomarkers has expanded in situations in which the diagnosis is ambiguous. Alpha-defensin, a human antimicrobial peptide produced by neutrophils in response to infection, can be measured in synovial fluid aspirates. Using immunoassay, its presence has shown very high sensitivity (96% to 100%) and specificity (95% to 99%) for the diagnosis of PJI.64-66 The utility of radiology in the diagnosis of PJI is ­limited, and the AAOS clinical practice guideline does not recommend the routine use of plain radiographs, CT scans, or MRI for the diagnosis of PJI.59 Enhanced imaging techniques, such as single-photon emission CT/positron emission tomography (SPECT/PET) scans, may improve future diagnostic capabilities, as nuclear imaging is not obstructed by the implants.67

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advanced screening. Blood tests should be performed in patients with risk factors for PJI as well as for all patients undergoing revision. C-reactive protein (CRP) level and erythrocyte sedimentation rate (ESR) have been shown to have a high sensitivity and a good negative predictive value, and they are cost effective. Joint aspiration is based on elevation of both CRP level (>N10 mg/L) or ESR (>N30 mm/h) or a high index of clinical suspicion.60 All synovial fluid aspirates should be evaluated for total white blood cell count, with particular attention paid to the differential count (% polymorphonuclear neutrophils). In addition, the fluid should be sent for aerobic and anaerobic cultures. The thresholds for the MSIS minor criteria should be followed to establish the diagnosis of chronic periprosthetic infection58 (Table 6). Aerobic and anaerobic cultures remain the most effective method for diagnosis and organism identification. Office specimens should be optimized by being placed in blood culture vials, and swabs should be avoided.61 Multiple publications report that Gram stains lack sensitivity and specificity, and they are no longer recommended at any point in the diagnosis of PJI. Synovial fluid cultures have high specificity but poor sensitivity; a negative culture does not rule out PJI. A recent international multicenter study reported that preoperative synovial fluid aspirations yielded organisms in only 45.2% of cases with confirmed knee PJI, with false-negative rates relative to intraoperative cultures of 46.0%, and a discordance rate of 21.4%.62 The addition of rapid “point-of-service” leukocyte esterase testing has been shown to be highly sensitive and specific for the presence of PJI and is part of the MSIS minor criteria, but the test requires clear synovial fluid for accuracy.63 Difficulty arises when assessing persistently painful knee joints that are not obviously infected, have normal

PJI Treatment Results The treatment of PJI remains a formidable challenge. A significant amount of variability exists with regard to the best treatment options, timing, outcomes, and definition

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Table 8

Risk Factors for Irrigation/Débridement and Polyethylene Exchange Increasing age Duration of symptoms (> 2 weeks) Presence of prolonged wound drainage Staphylococcus aureus infection Resistant organisms Immunocompromised host Rheumatoid arthritis Diabetes mellitus Malnourishment Presence of sinus tract Radiographic evidence of osteitis Radiographic evidence of component loosening

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of success. The optimal treatment of each scenario has yet to be elucidated, and failure rates remain high. A recent evaluation of nearly 1.5 million patients in the Medicare database, treated by various techniques for PJI, showed a 26% overall recurrence rate of infection.68 Antibiotic suppression alone as a treatment of PJI is recommended only in a patient who is medically debilitated and unable to undergo surgery. The infectious agent should be a low-virulence organism, and the patient should be in stable condition, have well-fixed components, and be able to be treated with a suitable oral antibiotic agent. The literature suggests that the success rate of antibiotic suppression is extremely variable and should be used only when the preceding criteria are met; success ranges from approximately 20% to 80%. Irrigation and débridement with polyethylene exchange is an attractive, low-­morbidity option for both the surgeon and patient (Table 8). It is generally performed in one operation and creates minimal functional disruption. The results in the literature have been inconsistent, however, and many treatment variables exist. Historically, it is generally agreed that open irrigation and débridement for an infected TKA should be reserved for patients with an acute onset of infection, as irrigation, débridement, and component retention for treatment of a chronic infection (signs and symptoms for more than 4 weeks) have been associated with high failure rates and poor outcomes, and therefore should not be considered. Results of treatment with open irrigation and débridement have been quite variable and, when viewed as a whole, probably much more sobering that most surgeons would

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anticipate. A 2002 meta-analysis evaluated 530 patients treated with open irrigation and débridement for acute PJI and showed an overall success rate of 33.6%. This study included acute postoperative infections and late acute hematogenous infections. The wide range of success and failure suggests that numerous variables affect outcomes, including the timing of surgery, patient risk factors, surgical technique, and the infecting organism. Of these variables, timing of surgery has been thought to be the most controversial factor in the success of irrigation and débridement with polyethylene exchange. Several studies have reported that the time from onset of symptoms (less than 4 weeks) to surgical irrigation and débridement was not a factor in the outcome; however, most studies have shown improved success when treatment is initiated after a shorter duration of symptoms (less than 2 weeks). Primary exchange arthroplasty involves the removal of all components and the reinsertion of another prosthesis in a single operation. Although an attractive option, data in the literature are limited, based on only small numbers of patients. The two largest historical published series involve only 22 and 18 patients.69,70 Although a success rate ranging from 89% to 91% was reported, it is important to keep in mind that strict inclusion and exclusion criteria exist to increase success of this procedure. Factors that influence a successful single-stage exchange include a host who was not immunocompromised, a known organism with absence of antibiotic resistance, meticulous surgical technique, adequate bone stock for reconstruction, and a targeted antibiotic approach. Using these criteria, a study reported an infection-free survivorship of 100% in 28 patients undergoing single-stage revision TKA at a minimum 3-year follow-up.70 These results merit continued evaluation of the technique, as it has potential benefit to the patient and to healthcare system economics. Two-stage exchange arthroplasty is considered the gold standard for the treatment of a chronic periprosthetic infection. The procedure involves the removal of the infected prosthesis and thorough débridement to remove any necrotic and foreign material, including all cement. A high-dose antibiotic cement spacer is placed at the time of the initial surgery, and the patient is treated with a course of intravenous antibiotics tailored to treat the infecting organism. Treatment variables include the amount and type of antibiotics to be used in the spacer, the type of spacer (mobile versus articulating), the length of intravenous antibiotic therapy, and the interval between resection and reimplantation. Two general categories of antibiotic spacer are described in the literature: static and articulating. Static spacers preserve the joint space and minimize the generation of cement debris, but do not allow motion during

© 2017 American Academy of Orthopaedic Surgeons

Chapter 20: Complications of Knee Arthroplasty

© 2017 American Academy of Orthopaedic Surgeons

this situation has been successfully performed using multiple techniques, including intramedullary nails, locked compression nails, modular fusion implants, plating, and external fixation. In a recent systematic literature review, a decision analysis was performed to determine the treatment method most likely to yield the highest quality of life for patients whose two-stage TKA reimplantation was unsuccessful. Given the best available evidence, knee arthrodesis should be strongly considered as the treatment of choice for patients with a persistently infected TKA.77 A case series of 26 patients treated with intramedullary nailing following septic failure of revision TKA reported that one-half had a persistent infection requiring additional surgery, 73% had persistent pain, and all outcome scores showed marked quality-of-life impairment.78 A national database was used to compare 2,634 arthrodeses and 5,001 transfemoral amputations in the treatment of failed septic TKAs from 2005 to 2012. Patients who underwent transfemoral amputation tended to be older and have more medical comorbidities. Arthrodesis patients had a significantly higher rate of postoperative infection (14.5% versus 8.3%; P < 0.0001) and transfusion (55.1% versus 46.8%; P < 0.0001), whereas patients who underwent transfemoral amputation had a higher rate of systemic complications (31.5% versus 25.9%; P < 0.0001) and in-hospital mortality (3.7% versus 2.1%; P < 0.0001). The transfemoral amputation cohort had lower hospital charges ($79,686 versus $84,747; P < 0.004), longer length of stay (11 versus 7 days; P < 0.0001), and a higher 90-day readmission rate (19.4% versus 16.9%). The data suggested an increasing trend toward transfemoral amputation compared with arthrodesis for the treatment of a failed infected TKA.79

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the interval period. Static preformed blocks have been associated with increased bone loss, migration, and extensor mechanism necrosis, and generally should be avoided. A molded static spacer, in which the cement is placed in a doughy state to allow it to mold to the bony surfaces, can prevent many of the problems associated with a preformed block spacer. The published results suggest equal rates of infection eradication with both spacer types but a marginal functional advantage with an articulating spacer.71 Several prior studies in the literature have shown clinical success in eradication of infection rate between 85% and 91%.72,73 However, recent reports suggest more sobering outcomes, with high failure rates attributed to numerous risk factors.74 A review of the outcomes of patients undergoing two-stage exchange in infection following TKA reported on 504 patients who underwent resection arthroplasty and placement of an antibiotic spacer. The mean follow-up after initial spacer implantation was 56.2 months; 81.4% had successful reimplantation. Of 87 patients who did not undergo reimplantation, 6 (6.9%) required amputation, 5 (5.7%) underwent a Girdlestone procedure, 4 (4.6%) underwent arthrodesis, and 72 (82.8%) underwent spacer retention; 36 patients died during the interstage period.75 Because of the poor reported outcomes in the management of PJI across all treatment spectrums, the role of prolonged antibiotic therapy following treatment is being evaluated more closely. A retrospective review reported on a cohort of patients who received 6 months of oral antibiotics following treatment of PJI (either irrigation and débridement or two-stage exchange). The patients were matched to a similar cohort of patients who did not receive oral antibiotics. The 5-year infection-free pros­thetic survival was higher for the irrigation and débridement group as well as the two-stage group receiving a course of oral antibiotics.76 Knee fusion and transfemoral amputation are the salvage options when all attempts to treat and recover a functional knee arthroplasty have been exhausted. When multiple treatments fail to eradicate knee PJI, or the repetitive procedures have resulted in the loss of supportive bone and/or functional musculotendinous attachments, revision reimplantation of a functioning durable knee prosthesis may not be possible. In these situations, surgeons must decide on more drastic measures to either salvage the extremity, save the patient from systemic sepsis, or avoid recurrent unsuccessful surgery. These end-stage salvage options are fortunately necessary in only a small percentage of patients, but when performed, they result in disability and decreased patient mobility. Limb salvage obviously appeals to patients and surgeons after failed infection treatment. Knee fusion in

Polyethylene Wear and Associated Complications Slif D. Ulrich, MD; Christopher Samujh, MD; Viktor E. Krebs, MD; Arthur L. Malkani, MD

The number of TKAs performed continues to increase, and improvements in secure long-term survivorship are necessary to decrease costs and revision rates.80 The common causes for failure and revision surgery are varied, with infection and instability accounting for most. Polyethylene wear and subsequent particle-induced osteolysis still remains an important cause of midfailure to late failure. Recent studies show a decline in wear-related revisions.81-84 One study reported that the number of late revisions for polyethylene wear has decreased from more than 40% in 2002 to 4.3% in 2012.82 A recent study showed a change in failure distribution of polyethylene wear; the overall occurrence of failure because of polyethylene wear was 7% compared with a polyethylene wear failure rate

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of 10% to 25% in earlier studies.81 Polyethylene wear, however, was responsible for 18.5% of late TKA failures. The causes of premature polyethylene wear are related to methods of polyethylene manufacturing, implant design, patient factors (eg, body mass index [BMI]), surgical technique, and component alignment. As the need for knee arthroplasty continues to increase, surgeons and the industry will continue to work to reduce polyethylene wear and osteolysis by advancing the science of polyethylene manufacturing, implant design, component positioning/ alignment, and patient-related factors to further improve implant survival and durability.

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Evolution of Polyethylene The science and manufacturing of polyethylene have undergone considerable advancement in the past 10 to 15 years, and improvements may be one factor contributing to decreased TKA failure rates related to wear and osteolysis.81-84 Issues with polyethylene were initially much larger in total hip arthroplasty (THA) failure and stimulated the overall improvements that have been continued with TKA, which some authors believe is premature because of the long-term success of conventional polyethylene and 90% to 98% survivorship reported at 15 to 20 years. The TKA bearing surface, with its sliding, rolling, and rotational behavior, is not as conforming as in THA; therefore, contact stresses on the polyethylene are much higher in THA, and wear mechanisms differ. The shift away from polyethylene irradiation in air is considered by many to be the most important improvement in reducing free-radical formation that ultimately results in osteolysis. Considerable research has focused on sterilization, packaging, cross-linking, and manufacturing techniques. The industry has come a long way with contemporary polyethylene knee bearings being gamma sterilized and packaged in inert environments or ethylene oxide–sterilized. Many proprietary manufacturing processes have also been developed, and each company has published data defining advantages and improved wear resistance that generally fall into one of two categories: highly cross-linked polyethylene (HXLPE) or vitamin E-infused polyethylene (VEPE). The use of newer generations of polyethylene in TKA is still controversial as conventional polyethylene has good long-term clinical outcomes and is cheaper than HXLPE and VEPE. Additional work is needed to determine if newer generations of polyethylene are not only safe to use but also clearly beneficial, to justify increased costs. HXLPE is already in its second generation, with thermal stabilization added to the manufacturing process by remelting or annealing the plastic to minimize oxidation and maximize cross-linking. Remelting is a process

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undertaken at a higher temperature to convert the crystalline structure of polyethylene back to an amorphous state that releases free radicals. Free-radical elimination by this method is nearly complete, but it reduces the crystallinity of the polyethylene and makes the material potentially more brittle and less resistant to fatigue-crack propagation. Despite promising results of sequentially irradiated and annealed second-generation HXLPE in the literature on THA, there are concerns about its benefits in TKA. The knee bearing surface has a wear mechanism different from that of the hip, in which wear is abrasive and adhesive; in TKA, pitting and delamination are seen. One study proposes that the reduction of mechanical properties by newer generations of polyethylene and resistance to fatigue and crack propagation may lead to breakage and failure of the insert over time.85 Recent studies, however, have demonstrated the safety of firstand second-generation HXLPE in the setting of TKA. A multicenter minimum 5-year follow-up study of second-­ generation HXLPE versus conventional polyethylene did not demonstrate any osteolysis or insert failure in either group.86 Another study compared two first-generation HXLPEs with conventional polyethylene and no revisions were noted as a direct result of insert failure.87 Antioxidant vitamin–infusing polyethylene with vitamin E is another method developed recently to improve on earlier-generation polyethylenes. Synthetically derived vitamin E is either added to the polyethylene powder before cross-linking or diffused into irradiated polyethylene to stabilize free radicals.88 Knee simulator studies have attempted to answer the question of whether VEPE is a viable alternative to conventional polyethylene. Conventional polyethylene laced with vitamin E was compared with plain conventional polyethylene with both samples undergoing the same postprocessing sterilization.89 The VEPE showed no signs of oxidation or reduction in mechanical properties, whereas the conventional polyethylene did. Concerns with VEPE lie mainly in the intra-articular and systemic effects of vitamin E.85 The natural form of vitamin E, α-tocopherol, is nontoxic to humans; however, the effects on the structure of vitamin E of steps in the VEPE manufacturing process, such irradiation, are unknown.88 Etiology and Risk Factors The true incidence of polyethylene wear and osteolysis is difficult to quantify because the only information published is related to failures and revisions. As an isolated cause of failure, rates of wear and osteolysis range from 4.3% to 7.0% in recent literature.82,83 The true incidence is likely much higher, as wear and osteolysis always occur in conjunction with all other failure mechanisms, and a patient can remain asymptomatic up to

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Chapter 20: Complications of Knee Arthroplasty

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Table 9

Factors That Affect Polyethylene Wear and Osteolysis in Total Knee Arthroplasty Implant Design Bearing conformity, congruity, and constraint Locking mechanisms Fixed versus mobile bearing Materials and finish Patient Factors Body mass index/weight Activity level Age Surgical Technique Alignment Balance and stability Kinematics

may be more responsible for osteolysis due to the high-volume submicron particles that are generated. One study showed that wear rates were lower for rotating-platform inserts than for fixed-bearing inserts. In addition, the backside wear rate was lower for fixed-bearing inserts mated to polished cobalt-chromium trays than for inserts from rough titanium trays.96 However, two groups of researchers showed that rotating-platform and fixed-­ bearing inserts had similar tibiofemoral damage.97 The level of constraint also has an effect on wear patterns. One study compared 18 valgus-varus constrained (VVC) liners to a matched group of posterior-stabilized liners in a retrieval analysis and showed statistically more damage in the posts of the VVC group (13.0 ± 5.0, compared to 4.7 ±1.9 in the PS group; P < 0.001).98 The polyethylene wear patterns are influenced by patient factors such as age, BMI, and activity level. As indications have expanded, younger patients are undergoing arthroplasty with unrealistic expectations to return to age-appropriate activity levels. In a recent study, the following definitions of high activity in arthroplasty patients were proposed: more than 3 million cycles/ year; 1 hour/day in high-activity mode; 40% of cycles in high-­activity mode.99 The Finnish Arthroplasty Registry revealed that patients younger than 55 years had worse 5-year implant survival rates (92%) compared with those between ages 56 and 65 years (95%) and those older than 65 years (97%; P < 0.001). In a retrospective cohort study of 1,291 revisions for aseptic loosening, patients with morbid obesity had an increased risk of repeat revision,

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the point of implant failure. Numerous studies suggest that polyethylene wear–induced periprosthetic osteolysis is a time-related progression that is closely associated with mechanical and biologic etiologic dynamics.90 The wear particle accumulation in TKA results from a combination of delamination, pitting, adhesion, abrasion, and burnishing backside wear.91 Decreasing wear and bioactive particle generation has been the prime strategy for elimination of osteolysis and aseptic loosening. Unfortunately, these causes of failure are multifactorial and involve the inseparable aspects of TKA: biology, implant design, patient factors, and, most important, surgical technique (Table 9). Advances in the basic science of particle-induced osteolysis are becoming clinically relevant, as the understanding of the process is allowing the development of interventions that may effectively retard or stop the progression. Polyethylene particles accumulating in the joint space activate several cell lines of innate and adaptive immunity. The activation of macrophages into an M1 phenotype is accountable for the triggering and maintenance of chronic inflammation, which enables growth of the interface membrane. In addition, polarized M2 macrophages produce anti-inflammatory cytokines (such as CCL2, CCL5, CXCL12, and CX3CL1) and homeostatic repair molecules.92,93 The predominant feature of periprosthetic osteolysis is an overactivation of the receptor activator nuclear factor kappa-B ligand (RANKL)–induced osteoclastogenesis caused by an interaction of the RANKL/RANK/ osteoprotegerin axis.94 Elevated RANKL expression leads to osteolysis and, subsequently, to bone loss. However, osteoprotegerin blocks the activation of osteoclasts and thereby decreases bone resorption. In the future, pharmacologic interventions may be able to target chronic inflammation and osteoclast maturation in a local or systemic application. Comparable studies are available for other osteolysis-targeted therapies including anticytokine (such as antitumor necrosis factor and anti-interleukin-1/ interleukin-6), antienzyme (such as inhibition of matrix metalloproteinase-9), hormonal (such as parathyroid hormone and calcitonin), and pharmacologic (such as simvastatin and diphosphonate). Knee prostheses begin to wear down the moment they are implanted; polyethylene properties and design elements of the metallic components have been shown to influence the durability timeline. Polyethylene quality, sterilization, processing, and thickness have been shown to have the greatest effect on debris generation and osteolysis. Polyethylene inserts at least 8 mm in thickness are recommended in mobile bearings and obese patients.95 The introduction of tibial tray modularity is likely the next most important cause of wear debris, and these

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reoperation, and infection. The implant survival rates were significantly different for morbidly obese and nonmorbidly obese patients, 96% and 100% at 5 years, and 81% and 93% at 10 years, respectively.100 However, a literature search of 209 knee revisions identified no host factors associated with aseptic loosening. They found that obesity (BMI of 30 kg/m2 or greater) was not associated with aseptic loosening.101 Surgical technique and factors are becoming the most important modifiable aspects of knee arthroplasty surgery to decrease implant wear and failure. Deviations from the optimal alignment of the mechanical axis can lead to a localized increase in surface contact pressures. Alterations also lead to subtle instability, and a combination of the two can lead to increased polyethylene wear and mechanical overload of the underlying bone. Mechanical axis alignment of the tibial component in 3° of varus leads to almost double the polyethylene volumetric penetration rate.102 This malalignment and instability permutation results in wear debris, direct bone damage, synovial fluid access to the implant bone interface, and osteolysis.98,103 Increasing the level of constraint to balance a poorly aligned knee also affects joint wear. One study showed significantly more damage in the posts of the VVC inserts versus posterior-stabilized inserts (P < 0.001). In addition, within the VVC group, the total damage score and cold flow damage were significantly higher with excessive joint line changes (5 mm or greater; P = 0.01). Damage scores were increased with femoral component malposition (P = 0.04), anterior tibial slope (P = 0.04), and tibial component malposition (P = 0.04).98 One study assessed the effect of limb alignment, implant position, and joint line position on the pattern of wear in a retrieval analysis of 83 posterior stabilized tibial inserts. The total damage score was significantly higher in knees with postoperative varus alignment greater than 3° (P = 0.03). In addition, the total damage score to the post was significantly more in knees with joint line elevation greater than 9.7 mm ± 3.9 mm, compared to 6.5 mm ± 3.7 mm in knees with less joint line elevation (P = 0.05).104 In another retrieval study of 17 inserts that were implanted with a tibial varus angle of greater than 3°, twice the medial compartment wear was observed.102 In contrast, previous studies have reported that mechanical alignment outliers with a radiographic axis of 0° ± 3° had a lower revision rate than those that were mechanically aligned within ±3° of anatomic alignment resulting from aseptic loosening, mechanical failure, or wear. Diagnosis Wear-induced osteolysis is often asymptomatic, and the lesions are frequently identified incidentally on routine

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follow-up radiographs or CT and MRI scans obtained for other reasons. Symptomatic osteolysis should be evaluated like all painful knee arthroplasties, with infection ruled out first, as the radiographic findings can be similar. The use of CT or MRI is highly effective for assessing osteolysis and wear and has been shown to be superior to radiographs in sensitivity and accuracy.105 There is no currently accepted or validated classification system to evaluate patients or guide treatment of wear and osteolysis in TKA. Treatment and Results Radiographic observation may be reasonable management for focal asymptomatic and nonprogressive tibial and femoral lesions. In the absence of clinical symptoms, stable osteolytic lesions less than 1 cm can be closely monitored with serial radiographic follow-up and referral to a metabolic bone specialist versed in the use of osteolysis-targeted therapies.106 There is no real consensus on a lesion size that warrants surgery. The decision tree is multifactorial and is based on the location of the lesion, the level of progression, the frailty of the patient, and the symptoms. Surgical indications are based on the risk of failure or periprosthetic fracture with continued observation. Surgical treatment of a periosteolytic lesion in a well-fixed tibial and femoral component is guided by the size of the lesion, any progressive change in that size, and the presence of any associated symptoms. Focal defects can be treated intralesionally with impaction grafting and polyethylene exchange when the existing implants are well fixed, appropriately aligned in all planes, and the joint is well balanced with intact ligaments.106 This treatment requires that the defects be peripherally accessible through a cortical window. One study of 10 knees with a mean follow-up of approximately 5 years after window bone grafting and polyethylene exchange showed total incorporation of the graft material into previously lytic regions on radiographs at final follow-up; no revisions were required. The indications included lytic lesions that could potentially compromise mechanical stability and smaller lesions that showed expansion on serial radiographs. The lesion size in this study ranged from 2 to 6 cm on standard radiographs.107 Revision options are limited and are more challenging in larger, symptomatic, or progressive lesions that are at risk for fracture or catastrophic loosening. These defects require more complex reconstruction techniques. Metaphyseal bone defects that preserve the peripheral cortical rim with a thin shell and larger contained defects require distal stem fixation, structural allograft, or newer-­generation porous metal sleeves or cones (Figures 9 and 10). The use of a structural allograft has decreased

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Figure 9

AP (A) and lateral (B) radiographs of a failed right total knee arthroplasty (TKA), osteolysis, and bone loss along the medial tibial metaphysis in a 71-year-old patient. Intraoperative photographs demonstrate significant osteolytic segmental (C) and cavitary (D) defects along the medial tibial metaphysis. E, Intraoperative photograph obtained following revision TKA and augmentation of tibial defect using a femoral head allograft. F, Postoperative lateral radiograph demonstrates revision TKA and treatment of osteolytic defect using a femoral head allograft.

in recent years due to high failure rates with long-term follow-up as well as with the advent of highly porous metal augments, cones, and sleeves that accentuate biologic metaphyseal fixation.108 Several midterm clinical studies (range, 1.0 to 8.8 years) with porous tantalum cones for bone loss in the revision setting have shown promising results, with a cumulative mean revision rate for aseptic cone loosening of 1.1%.109,110 In addition, the clinical outcomes of titanium sleeves at short-term follow-up (range, 2.0 to 5.3 years) have been excellent, with a 2.6% revision rate for aseptic loosening.111-113 Surgical goals include suitable management of bone loss and a strategy to restore or maintain implant stability and limb alignment. In addition, it is crucial to assess the status of the epicondyles to best determine the patency of the collateral ligaments. In the absence of functional collateral ligaments, a more

© 2017 American Academy of Orthopaedic Surgeons

constrained or hinged prostheses is suggested to maintain coronal stability and to prevent failure. Summary The demographics of the population with indications for TKA is not only growing, it is changing to include younger, actively working patients with ligament damage and posttraumatic arthritis in addition to older patients with multiple comorbidities and poor bone stock. Surgeons performing knee arthroplasty must scrupulously select and prepare patients (and themselves) to avoid complications and achieve lasting results. It is important to educate patients on the risks and explain that they cannot be completely eliminated; only modified. Industry partners have helped develop, study, and refine knee implants to a

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Figure 10

AP (A) and lateral (B) radiographs of failed left total knee arthroplasty (TKA) in a 65-year-old woman with tibial baseplate subsidence and a large osteolytic lesion along the anterior tibial metaphysis. C, Intraoperative photograph of the explanted polyethylene liner shows delamination and pitting. AP (D) and lateral (E) radiographs obtained following revision TKA with a press-fit tibial cone for reconstruction of the metaphyseal defect.

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point at which durability is no longer a common reason for failure. Periprosthetic fracture, infection, and wear are all aspects of knee arthroplasty that surgeons can directly address and manage before, during, and after performing the surgery. Patient selection and optimization have been shown to improve outcomes and decrease these complications. Early to midterm complications are a function of how well the surgery is performed and how accurately the implants are fixed and aligned; when done well, data confirms a decreased risk for instability, wear, and periprosthetic fracture. A painful knee arthroplasty that does not function for the patient is a complication, and the surgeon’s evaluation and management remains a critical responsibility. A systematic, cost-effective approach to the evaluation and workup of a painful knee arthroplasty should be undertaken to rule out infection and avoid perpetuation or escalation of any potential problem. Consensus on PJI evaluation and treatment has become more organized and evidence-based, but many controversies still exist regarding optimal strategies because of the extreme variability that exists in patients, organisms, and treatment. It is important to be aware of the current information on important knee arthroplasty complications; emphasis should be placed on the need to support the mandatory implementation of a global implant registry, standardize clinical data collection, and establish large-scale prospective clinical trials to evaluate the multitude of factors that influence knee arthroplasty complications, function, and longevity.

Key Study Points • Major risk factors for periprosthetic fracture, PJI, and accelerated wear complications after knee arthroplasty should be identified. • The AO Foundation UCS should be applied to periprosthetic knee fractures for a rational approach to treatment. • The MSIS definition of PJI and criteria for diagnosis, and the AAOS clinical practice guidelines on the diagnosis of periprosthetic joint infection should be applied for standardized approaches to diagnosis and treatment. • The different evidence-based treatment options for periprosthetic fracture, PJI/infection, and polyethylene wear complications after knee a­ rthroplasty should be adhered to so that new techniques are incorporated as available.

Annotated References 1. Tosounidis TH, Giannoudis PV: What is new in distal femur periprosthetic fracture fixation? Injury 2015;46(12):2293-2296. Medline  DOI The number of periprosthetic fractures related to TKA is increasing. Most are treated surgically, with nonsurgical management reserved for medically unfit patients who cannot tolerate anesthesia and those who were nonambulatory before the injury. 2. Hanschen M, Aschenbrenner IM, Fehske K, et al: Monoversus polyaxial locking plates in distal femur fractures: A prospective randomized multicentre clinical trial. Int Orthop 2014;38(4):857-863. Medline  DOI

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In this study, 27 patients with a distal femoral fracture (native knee and periprosthetic) were randomized for treatment with either a monoaxial LISS or a polyaxial locking plate. Polyaxial osteosynthesis tended to result in better functional knee scores and a higher range of motion and to lead to more rapid fracture healing. Level of evidence: I. 3. Meek RM, Norwood T, Smith R, Brenkel IJ, Howie CR: The risk of peri-prosthetic fracture after primary and revision total hip and knee replacement. J Bone Joint Surg Br 2011;93(1):96-101. Medline  DOI The authors of this study retrospectively evaluated a large series of THAs and TKAs (including 44,511 primary and 3,222 revision TKAs). At 5 years postoperatively, the rate of fracture was 0.6% after primary TKA and 1.7% after revision TKA. Comparison of survival analyses showed periprosthetic fractures to be more likely in females, patients older than 70 years, and after revision arthroplasty. Level of evidence: III. 4. Schütz M, Perka C: Periprosthetic Fracture Management. New York, NY, Thieme, 2013, pp 782-795. 5. Drew JM, Griffin WL, Odum SM, Van Doren B, Weston BT, Stryker LS: Survivorship after periprosthetic femur fracture: Factors affecting outcome. J Arthroplasty 2016;31(6):1283-1288. Medline  DOI In this retrospective review of 291 patients treated surgically for periprosthetic fracture, patients had a 24% risk of either death or revision surgery at 1 year. Factors contributing to increased mortality were nonmodifiable. Risk of reoperation was minimized with greater span of fixation and performance of revision arthroplasty. Level of evidence: III.

In a review of 30,624 patients with primary or revision THA or TKA, the proportion of admissions for periprosthetic fracture ranged from 4.2% to 7.4% annually. Compared with patients admitted for other diagnoses, individuals admitted with periprosthetic fracture were older, more often female, and more often admitted emergently/urgently; they also had longer lengths of hospital stay, higher rates of discharge to places other than home, and elevated mortality. Level of evidence: III. 7. Phillips JR, Boulton C, Morac CG, Manktelov AR: What is the financial cost of treating periprosthetic hip fractures? Injury 2011;42(2):146-149. Medline  DOI In 146 patients treated for periprosthetic femoral fracture after THA, fixation of the fracture was performed in 61 cases, revision arthroplasty in 62 cases, and nonsurgical treatment in 23. Mean cost of treatment was £23,469 per patient. Level of evidence: III. 8. Bozic KJ, Kamath AF, Ong K, et al: Comparative epidemiology of revision arthroplasty: Failed THA poses greater clinical and economic burdens than failed

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The authors of this study investigated 235,857 revision THAs and 301,718 revision TKAs. Mean (±SD) hospitalization costs were slightly higher for revision THA ($24,697 ± $40,489) than revision TKA ($23,130 ± $36,643). PJI and periprosthetic fracture were associated with the greatest length of stay and highest cost for revision THAs and TKAs. Level of evidence: III. 9. Johnston AT, Tsiridis E, Eyres KS, Toms AD: Periprosthetic fractures in the distal femur following total knee replacement: A review and guide to management. Knee 2012;19(3):156-162. Medline  DOI This article describes the risk factors for development of distal periprosthetic fractures and the options available for management, which requires equipment, perioperative support, and surgical skills of both trauma and revision arthroplasty services. 10. Märdian S, Wichlas F, Schaser KD, et al: Periprosthetic fractures around the knee: Update on therapeutic algorithms for internal fixation and revision arthroplasty. Acta Chir Orthop Traumatol Cech 2012;79(4):297-306. Medline This article presents an algorithm for the epidemiology of periprosthetic fractures related to TKA. Progressive development of new implant methods and refinement of soft-tissue preserving surgical techniques are key to regaining prefracture levels of function. 11. Hoffmann MF, Jones CB, Sietsema DL, Koenig SJ, Tornetta P III: Outcome of periprosthetic distal femoral fractures following knee arthroplasty. Injury 2012;43(7): 1084-1089. Medline  DOI

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6. Toogood PA, Vail TP: Periprosthetic fractures: A common problem with a disproportionately high impact on healthcare resources. J Arthroplasty 2015;30(10):1688-1691. Medline  DOI

TKA. Clin Orthop Relat Res 2015;473(6):2131-2138. Medline  DOI

In a retrospective study of 55 consecutive distal femoral periprosthetic fractures treated with locked-plate fixation, 25 fractures (69.4%) healed after the index procedure, nonunion developed in 8 fractures (22.2%), and 9 patients (25%) had radiographic diagnoses of anterior femoral cortex notching. The distance from the anterior flange of the femoral component to the fracture was shorter in patients with anterior notching. Level of evidence: III. 12. Duncan CP, Haddad FS: The Unified Classification System (UCS): Improving our understanding of periprosthetic fractures. Bone Joint J 2014;96-B(6):713-716. Medline  DOI The principles that underpin evaluation and treatment of periprosthetic fractures are common across the musculoskeletal system. The UCS presents a rational approach to treatment, irrespective of the bone that is broken or the joint involved. 13. Van der Merwe JM, Haddad FS, Duncan CP: Field testing the Unified Classification System for periprosthetic fractures of the femur, tibia and patella in association with knee replacement: An international collaboration. Bone Joint J 2014;96-B(12):1669-1673. Medline  DOI

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To evaluate reliability of the UCS, an international panel of experts and preexperts in orthopaedic surgery evaluated 15 radiographs. After 6 weeks they evaluated the same radiographs again, but in a different order. The interobserver reliability κ values for the experts and the preexperts were 0.741 and 0.765, respectively. The weighted κ values for intraobserver reliability for the experts and preexperts were 0.898 and 0.878, respectively. Level of evidence: I.

Records of 19 patients with a distal femoral periprosthetic fracture following TKA treated by locked-plate osteosynthesis were evaluated. Successful union was achieved in 18 patients. Significant reduction in the range of motion and (Western Ontario and McMaster Universities Arthritis Index score were evident at follow-up. Secondary procedures were required in six patients to achieve union or to address reduced range of motion. Level of evidence: IV.

14. Alden KJ, Duncan WH, Trousdale RT, Pagnano MW, Haidukewych GJ: Intraoperative fracture during primary total knee arthroplasty. Clin Orthop Relat Res 2010;468(1):90-95. Medline  DOI

19. Shin YS, Kim HJ, Lee DH: Similar outcomes of locking compression plating and retrograde intramedullary nailing for periprosthetic supracondylar femoral fractures following total knee arthroplasty: A meta-analysis. Knee Surg Sports Traumatol Arthrosc 2016;Feb:20. Medline

The authors of this study reviewed 17,389 primary TKAs performed between 1985 and 2005 and identified 67 intraoperative fractures, including 49 femur fractures, 18 tibia fractures, and no patella fractures. Intraoperative fracture occurred more commonly in women (80.6%) and in the femur (73.1%). Most fractures occurred during exposure and bone preparation and trialing of components. In 14 patients (21%), revision was performed at an average of 2.8 years. Level of evidence: III. 15. Whitehouse MR, Mehendale S: Periprosthetic fractures around the knee: Current concepts and advances in management. Curr Rev Musculoskelet Med 2014;7(2): 136-144. Medline  DOI This review focuses on the incidence, risk factors, classification, investigation, and treatment options for TKA periprosthetic fractures.

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16. Kim W, Song JH, Kim JJ: Periprosthetic fractures of the distal femur following total knee arthroplasty: Even very distal fractures can be successfully treated using internal fixation. Int Orthop 2015;39(10):1951-1957. Medline  DOI A review of 32 periprosthetic fractures of the distal femur was undertaken, including 21 extremely distal fractures. Of the 21 Su type III fractures, 14 (66.7%) were treated using double plating and the minimally invasive plate osteosynthesis technique, whereas other fractures received a single plate. One nonunion was reported. Level of evidence: IV. 17. Ristevski B, Nauth A, Williams DS, et al: Systematic review of the treatment of periprosthetic distal femur fractures. J Orthop Trauma 2014;28(5):307-312. Medline  DOI In a systematic review of 44 studies and 719 distal femoral periprosthetic fractures, both locked plating and retrograde intramedullary nailing (RIMN) offered significant advantages over nonsurgical treatment and non– locked-plating techniques. Locked plating demonstrated a trend toward increased nonunion rates when compared with RIMN. Malunion was significantly higher with RIMN than with locked plating. 18. Gavaskar AS, Tummala NC, Subramanian M: The outcome and complications of the locked plating management for the periprosthetic distal femur fractures after a total knee arthroplasty. Clin Orthop Surg 2013;5(2):124-128. Medline  DOI

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Among eight studies in this meta-analysis, patients were treated with either locking plates or intramedullary nailing were similar in mean times to union, proportion of nonunions, and proportion of revisions. 20. Ebraheim NA, Kelley LH, Liu X, Thomas IS, Steiner RB, Liu J: Periprosthetic distal femur fracture after total knee arthroplasty: A systematic review. Orthop Surg 2015;7(4):297-305. Medline  DOI In this systematic review of 41 articles, the most common treatments of distal femoral periprosthetic fractures were reported to be locked plating and intramedullary nailing, with similar healing rates of 87% and 84%, respectively. The complication rate for locked plating was lower than for intramedullary nailing. 21. Bae DK, Song SJ, Yoon KH, Kim TY: Periprosthetic supracondylar femoral fractures above total knee arthroplasty: Comparison of the locking and non-locking plating methods. Knee Surg Sports Traumatol Arthrosc 2014;22(11):2690-2697. Medline  DOI A retrospective comparison between locking compression plates and nonlocking condylar buttress plates for treatment of distal femoral periprosthetic fractures showed healing without additional surgery in 13 of 14 patients with locking plates and 11 of 19 patients with nonlocking plates. Locking plate fixation reduced the incidence of overall complications, nonunion, malunion, loss of reduction, and additional surgery compared with nonlocking plate fixation Level of evidence: III. 22. Jones MD, Carpenter C, Mitchell SR, Whitehouse M, Mehendale S: Retrograde femoral nailing of periprosthetic fractures around total knee replacements. Injury 2016;47(2):460-464. Medline  DOI Eight different designs of primary TKA prostheses and four designs of retrograde femoral intramedullary nails were evaluated for compatibility using actual implants and Sawbones anatomic models. A nail was deemed compatible if insertion was possible through the femoral prosthesis. In most nails, insertion through most TKA components was technically feasible, but they were not compatible due to excessive force required for insertion, damage to the nail during insertion, or risk of anterior cortex perforation. Level of evidence: II.

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23. Gondalia V, Choi DH, Lee SC, et al: Periprosthetic supracondylar femoral fractures following total knee arthroplasty: Clinical comparison and related complications of the femur plate system and retrograde-inserted supracondylar nail. J Orthop Traumatol 2014;15(3):201-207. Medline  DOI The study included 42 cases of periprosthetic fractures proximal to TKA, with 24 cases being treated with the femur plate system and 18 cases with retrograde-inserted supracondylar. Fixation method and fracture type did not cause an increase in the complication rate, but there was a trend toward higher nonunion rates with the femur plate method and a higher refracture rate with the retrograde-inserted supracondylar nails method. Level of evidence: III. 24. Horneff JG III, Scolaro JA, Jafari SM, Mirza A, Parvizi J, Mehta S: Intramedullary nailing versus locked plate for treating supracondylar periprosthetic femur fractures. Orthopedics 2013;36(5):e561-e566. Medline  DOI A retrospective review of 63 patients with Rorabeck type II periprosthetic fractures of the distal femur was undertaken: 35 patients were treated with nailing and 28 with a locked plate. At 36 weeks, radiographic union was significantly greater in the locked-plate group. A greater perioperative transfusion rate was observed in the locked-plate group, but an overall lower rate of reoperation for any reason was also seen in this group. Level of evidence: III. 25. Meneghini RM, Keyes BJ, Reddy KK, Maar DC: Modern retrograde intramedullary nails versus periarticular locked plates for supracondylar femur fractures after total knee arthroplasty. J Arthroplasty 2014;29(7):1478-1481. Medline  DOI

26. Chen SH, Chiang MC, Hung CH, Lin SC, Chang HW: 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):224-231. Medline  DOI This study used a finite-element method to evaluate the differences between nail, locked-plate, and locked-plate/ allograft fixation in treatment of TKA-related distal femoral periprosthetic fractures. The locked-plate/allograft construct stabilized the fracture gap and reduced the implant stress more efficiently than the other two methods. 27. Mäkinen TJ, Dhotar HS, Fichman SG, et al: Periprosthetic supracondylar femoral fractures following knee arthroplasty: A biomechanical comparison of four methods of fixation. Int Orthop 2015;39(9):1737-1742. Medline  DOI

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28. 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;96B(1):114-121. Medline  DOI The fixation achieved with an intramedullary locking nail that allows the distal interlocking screws to be locked to the nail was compared with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. Fifteen human cadaver femora were used to simulate an AO 33A3 fracture pattern. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life and mean axial stiffness, but lower mean torsional stiffness. Locking nail constructs had significantly longer mean fatigue life than did nonlocking nail constructs. 29. Agarwal S, Sharma RK, Jain JK: Periprosthetic fractures after total knee arthroplasty. J Orthop Surg (Hong Kong) 2014;22(1):24-29. Medline After evaluating outcomes of 20 patients treated for periprosthetic fracture after TKA, locked plates were effective in managing distal femoral periprosthetic fractures. Periprosthetic patellar and tibial fractures were uncommon. Tibial fractures often warranted revision arthroplasty as a result of the loose implant. Technical aspects of fixation or revision surgeries were also described. Level of evidence: IV.

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Of 95 distal femoral periprosthetic fractures after TKA, 29 were treated with a retrograde intramedullary nailing (RIMN) and 66 with locked plates. Two nonunions (9%) were seen in the RIMN group, and 12 nonunions/delayed unions (19%) were seen in the locked-plate group (P = 0.34). Despite a greater quantity of screws in the distal fragment, the failure rate of locked plating was twice that of RIMN fixation. Level of evidence: III.

Sawbones anatomic model femurs were implanted with a femoral component of TKA. Femurs were osteotomized to produce an AO/OTA 33-A3 fracture pattern, and four different constructs were tested: (1) nonlocking plate; (2) polyaxial locking plate; (3) intramedullary fibular strut allograft with polyaxial locking plate; and (4) retrograde nail. The intramedullary fibular strut allograft with plate did not prove to be significantly better to the plate only.

30. Jassim SS, McNamara I, Hopgood P: Distal femoral replacement in periprosthetic fracture around total knee arthroplasty. Injury 2014;45(3):550-553. Medline  DOI Ten patients (mean age, 81 years) had TKA implant revision with a distal femoral replacement for periprosthetic fracture with associated poor bone stock. At a mean follow-up of 33 months (range, 4 to 72 months), all implants survived without need for reoperation. Mean postoperative Oxford Knee Score for the patients was 22.5 (range, 5 to 34). Level of evidence: IV. 31. Cannon SR: The use of megaprosthesis in the treatment of periprosthetic knee fractures. Int Orthop 2015;39(10):1945-1950. Medline  DOI The authors reported outcomes of 27 patients treated with an endoprosthetic replacement for periprosthetic fracture of the distal femur. All patients mobilized rapidly, and there were no cases of further revision in patients for whom clinical follow-up was available. Average Knee Society Score following treatment was 88 at 6 months postoperatively. Level of evidence: IV.

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32. Saidi K, Ben-Lulu O, Tsuji M, Safir O, Gross AE, Backstein D: Supracondylar periprosthetic fractures of the knee in the elderly patients: A comparison of treatment using allograft-implant composites, standard revision components, distal femoral replacement prosthesis. J Arthroplasty 2014;29(1):110-114. Medline  DOI Three different treatment methods for comminuted distal femoral periprosthetic fractures in 23 patients older than 70 years (average, 80 years) were compared. Techniques included seven allograft prosthesis composites, nine revision systems, and seven distal femoral endoprostheses. Surgical time and blood loss were significantly less in revision and distal femoral endoprostheses groups compared to the allograft prosthesis composites groups. Hospital stay was shortest for the distal femoral endoprostheses patients. No significant difference was found in the 6-week or 6-month Knee Society Scores. Level of evidence: III. 33. Lizaur-Utrilla A, Miralles-Muñoz FA, Sanz-Reig J: Functional outcome of total knee arthroplasty after periprosthetic distal femoral fracture. J Arthroplasty 2013;28(9):1585-1588. Medline  DOI This prospective matched-cohort study compared functional outcomes between 28 patients with femoral periprosthetic fractures and 28 with primary TKA. At a mean follow-up of 6.7 years, Knee Society Scores, knee motion, Western Ontario and McMaster Universities Arthritis Index, and Medical Outcomes Study 12-Item Short Form (SF-12) scores were significantly lower in the fracture group and were significantly decreased in comparison to preinjury status. Level of evidence: II.

2: Knee

34. Ebraheim NA, Ray JR, Wandtke ME, Buchanan GS, Sanford CG, Liu J: Systematic review of periprosthetic tibia fracture after total knee arthroplasties. World J Orthop 2015;6(8):649-654. Medline  DOI The authors of this study reviewed 13 articles that included 157 patients with tibial periprosthetic fractures. Based on the Felix classification, type 1 fractures were the most common. Subclass A was most commonly treated with locking plates, type B required a revision TKA, and type C was treated intraoperatively or nonsurgically. 35. Yoo JD, Kim NK: Periprosthetic fractures following total knee arthroplasty. Knee Surg Relat Res 2015;27(1):1-9. Medline  DOI The authors of this study emphasize good clinical outcomes after nonsurgical treatment of minimally displaced periprosthetic fractures, especially involving the patella; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prostheses. Considerations in choosing the appropriate treatment method should include stability of the prosthesis, fracture displacement, and bone quality. 36. Ruchholtz S, Tomás J, Gebhard F, Larsen MS: Periprosthetic fractures around the knee-the best way of treatment. Eur Orthop Traumatol 2013;4(2):93-102. Medline  DOI Based on a review of available techniques for treating distal femoral periprosthetic fractures, less invasive procedures present a valuable alternative to open techniques.

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Major advantages were lower rates of soft-tissue complications and implant failures. 37. Sarmah SS, Patel S, Reading G, El-Husseiny M, Douglas S, Haddad FS: Periprosthetic fractures around total knee arthroplasty. Ann R Coll Surg Engl 2012;94(5):302-307. Medline  DOI Based on review of 43 studies of periprosthetic fractures after TKA, this article outlines pathways to aid the surgeon’s choice of an appropriate treatment method. 38. Jujo Y, Yasui T, Nagase Y, Kadono Y, Oka H, Tanaka S: Patellar fracture after total knee arthroplasty for rheumatoid arthritis. J Arthroplasty 2013;28(1):40-43. Medline  DOI This article reported on a study of 329 TKAs performed in 230 female patients with rheumatoid arthritis at a mean follow-up of 6.2 years. Patellar resurfacing was performed in all cases. Five postoperative patellar fractures (1.51%) were identified; thin residual patellar thickness and the use of posterior-stabilized components were identified as significant risk factors. Level of evidence: III. 39. de Alencar PG, De Bortoli G, Ventura Vieira IF, Uliana CS: Periprosthetic fractures in total knee arthroplasty. Rev Bras Ortop 2015;45(3):230-235. Medline This review article states that for treatment of periprosthetic fracture around the knee, the surgeon should have broad knowledge of arthroplasty techniques and osteosynthesis as well as access to an extensive therapeutic arsenal, including a bone bank. 40. Adigweme OO, Sassoon AA, Langford J, Haidukewych GJ: Periprosthetic patellar fractures. J Knee Surg 2013;26(5):313-317. Medline  DOI The epidemiology and risk factors associated with periprosthetic patellar fractures are outlined in this article. Treatment options are discussed as they relate to injury mechanism, fracture severity, patellar component stability, and remaining bone. 41. Nam D, Abdel MP, Cross MB, et al: The management of extensor mechanism complications in total knee arthroplasty. AAOS exhibit selection. J Bone Joint Surg Am 2014;96(6):e47. Medline  DOI This article focuses on six of the most commonly encountered problems associated with the knee extensor mechanism during TKA: (1) patellar tendon disruption, (2) quadriceps tendon rupture, (3) patellar crepitus and soft-tissue impingement, (4) periprosthetic patellar fracture, (5) patellofemoral instability, and (6) osteonecrosis of the patella. The results in patients with a prior TKA are inferior to those in young adults with native patella. Surgical attempts at restoration of the extensor mechanism are warranted; however, outcomes of treatment are often poor. 42. Solarino G, Vicenti G, Moretti L, Abate A, Spinarelli A, Moretti B: Interprosthetic femoral fractures-A challenge of treatment. A systematic review of the literature. Injury 2014;45(2):362-368. Medline  DOI

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This article provides an updated and comprehensive list of diagnostic and therapeutic protocols for interprosthetic femoral fractures. Most fractures are best treated using appropriate plating techniques. 43. Ehlinger M, Czekaj J, Adam P, Brinkert D, Ducrot G, Bonnomet F: Minimally invasive fixation of type B and C interprosthetic femoral fractures. Orthop Traumatol Surg Res 2013;99(5):563-569. Medline  DOI Eight patients with interprosthetic femoral fractures were treated with minimally invasive locked-plate fixation. Early construct failure at 3 weeks in one patient required surgical revision. Healing was achieved in all eight patients after a mean of 14 weeks. One patient had malalignment, with greater than 5° of varus. No general or infectious complications occurred. Level of evidence: IV. 44. Alexander J, Morris RP, Kaimrajh D, et al: Biomechanical evaluation of periprosthetic refractures following distal femur locking plate fixation. Injury 2015;46(12): 2368-2373. Medline  DOI A segmental defect was created 6 cm proximal to the knee joint on a synthetic bone model and was fixed with a 246-mm locking plate. Fixation in the most proximal hole varied: a cerclage cable, a unicortical locking screw, or a bicortical locking screw was used. Proximal hole stabilization with a cerclage wire tolerated significantly higher failure forces while distributing forces distal to the area within the plate fixation. 45. Hoffmann MF, Lotzien S, Schildhauer TA: Clinical outcome of interprosthetic femoral fractures treated with polyaxial locking plates. Injury 2016;47(4):934-938. Medline  DOI

46. Platzer P, Schuster R, Luxl M, et al: Management and outcome of interprosthetic femoral fractures. Injury 2011;42(11):1219-1225. Medline  DOI In a study of 23 patients with interprosthetic femoral fracture who were treated either by lateral plate fixation (n = 19), by revision arthroplasty using a long stem (n = 2), or by plate fixation and revision arthroplasty (n = 2), 16 patients returned to preinjury activity level and were satisfied. In six patients, decrease of hip or knee function as well as severe limitation in gait and activities of daily living were noted. Fracture healing was achieved in 19 of 22 patients (86%) within 6 months. Failures of reduction and fixation were noted in 4 of 22 patients (18%). Level of evidence: IV. 47. Kurtz SM, Ong KL, Lau E, Bozic KJ, Berry D, Parvizi J: Prosthetic joint infection risk after TKA in the Medicare population. Clin Orthop Relat Res 2010;468(1):52-56. Medline  DOI

© 2017 American Academy of Orthopaedic Surgeons

48. Nikolaus OB, McLendon PB, Hanssen AD, Mabry TM, Berbari EF, Sierra RJ: Factors associated with 20-year cumulative risk of infection after aseptic index revision total knee arthroplasty. J Arthroplasty 2016;31(4): 872-877. Medline  DOI The authors reported that the cumulative risk of PJI was 1%, 2.4%, 3.3%, and 5.6% at 1, 5, 10, and 20 years, respectively, after revision TKA. 49. Kamath AF, Ong KL, Lau E, et al: Quantifying the burden of revision total joint arthroplasty for periprosthetic infection. J Arthroplasty 2015;30(9):1492-1497. Medline  DOI The authors present an evaluation of costs and patient characteristics associated with revision arthroplasty for PJI. 50. Crowe B, Payne A, Evangelista PJ, et al: Risk factors for infection following total knee arthroplasty: A series of 3836 cases from one institution. J Arthroplasty 2015;30(12):2275-2278. Medline  DOI This study reported that optimizing modifiable risk factors (such as patient tobacco use) before TKA may reduce the incidence of PJIs. 51. Kurtz SM, Lau E, Watson H, Schmier JK, Parvizi J: Economic burden of periprosthetic joint infection in the United States. J Arthroplasty 2012;27(8 suppl):61-5.e1. Medline  DOI

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A segmental defect was created in 21 synthetic osteoporotic adult femurs 6 cm proximal to the joint level, and specimens were stabilized with a 246-mm locking femur plate. Fixation in the most proximal hole varied: either a cerclage cable, a unicortical locking screw, or a bicortical locking screw was used. Proximal cerclage fixation demonstrated higher mean maximum axial force at failure, stiffness, and maximum torque. Level of evidence: III.

The 2001-2009 Nationwide Inpatient Sample was used to identify the relative incidence of PJI, which ranged from 2.0% to 2.4% of THAs and TKAs and increased over time. The mean cost to treat PJI of the hip was $5,965 greater than for knee PJI. The annual cost to US hospitals of infected revisions increased from $320 million to $566 million during the study period and was projected to exceed $1.62 billion by 2020. Level of evidence: II.

The annual hospital cost of revision surgery resulting from PJI is estimated to exceed $1.62 billion by 2020. 52. Kapadia BH, Johnson AJ, Issa K, Mont MA: Economic evaluation of chlorhexidine cloths on healthcare costs due to surgical site infections following total knee arthroplasty. J Arthroplasty 2013;28(7):1061-1065. Medline  DOI The use of chlorhexidine cloths before TKA demonstrated the potential to reduce SSIs and, therefore, decrease healthcare costs. 53. Pruzansky JS, Bronson MJ, Grelsamer RP, Strauss E, Moucha CS: Prevalence of modifiable surgical site infection risk factors in hip and knee joint arthroplasty patients at an urban academic hospital. J Arthroplasty 2014;29(2):272276. Medline  DOI Modifiable patient risk factors for SSI include obesity, anemia, malnutrition, and diabetes. The prevalence of these risk factors allows opportunities to optimize the condition of patients prior to TKA.

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54. Kapadia BH, Zhou PL, Jauregui JJ, Mont MA: Does preadmission cutaneous chlorhexidine preparation reduce surgical site infections after total knee arthroplasty? Clin Orthop Relat Res 2016;474(7):1592-1598. Medline  DOI The authors calculated relative risk reductions with use of a preoperative chlorhexidine cloth skin preparation protocol, and demonstrated a reduced relative risk of periprosthetic infection after TKA (infections with protocol: three of 991 [0.3%]; infections in control: 52 of 2,726 [1.9%]; relative risk: 6.3 [95% CI, 1.9-20.1]; P = 0.002). Level of evidence: III (therapeutic). 55. Farber NJ, Chen AF, Bartsch SM, Feigel JL, Klatt BA: No infection reduction using chlorhexidine wipes in total joint arthroplasty. Clin Orthop Relat Res 2013;471(10):31203125. Medline  DOI The use of chlorhexidine wipes was not found to reduce the incidence of SSI. Level of evidence: III. 56. Kapadia BH, Cherian JJ, Issa K, Jagannathan S, Daley JA, Mont MA: Patient compliance with preoperative disinfection protocols for lower extremity total joint arthroplasty. Surg Technol Int 2015;26:351-354. Medline Seventy-eight percent of patients (3,716 of 4,751 patients) were noncompliant with preoperative disinfection protocols. Although preoperative decolonization protocols may reduce SSIs, their efficacy is limited by patient compliance and comprehension. 57. Namba RS, Inacio MC, Paxton EW: Risk factors associated with deep surgical site infections after primary total knee arthroplasty: An analysis of 56,216 knees. J Bone Joint Surg Am 2013;95(9):775-782. Medline  DOI 2: Knee

A retrospective review of a cohort followed from 2001 to 2009 included 56,216 primary TKAs. Patient factors associated with deep SSI included a BMI of 35 kg/m 2 or greater (hazard ratio [HR] = 1.47), diabetes mellitus (HR = 1.28), male sex (HR =1.89), an American Society of Anesthesiologists score of 3 or greater (HR= 1.65), a diagnosis of osteonecrosis (HR = 3.65), and a diagnosis of posttraumatic arthritis (HR = 3.23). Surgical time was a risk factor, with a 9% increased risk per 15-minute increment. 58. Parvizi J, Gehrke T; International Consensus Group on Periprosthetic Joint Infection: Definition of periprosthetic joint infection. J Arthroplasty 2014;29(7):1331. Medline  DOI A group of experts determine a definition for PJI. 59. Parvizi J, Della Valle CJ: AAOS Clinical Practice Guideline: Diagnosis and treatment of periprosthetic joint infections of the hip and knee. J Am Acad Orthop Surg 2010;18(12):771-772. Medline  DOI The AAOS clinical practice guideline for PJI of the hip and knee is presented. 60. Diaz-Ledezma C, Lichstein PM, Dolan JG, Parvizi J: Diagnosis of periprosthetic joint infection in Medicare patients: Multicriteria decision analysis. Clin Orthop Relat Res 2014;472(11):3275-3284. Medline  DOI

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The authors determined the best diagnostic strategy for knee and hip PJI in the ambulatory setting for Medicare patients, using benefits, opportunities, costs, and risks evaluation through multicriteria decision analysis. Screening with serum markers before arthrocentesis was found to be the best strategy for diagnosing PJI in Medicare patients. Level of evidence: II. 61. Aggarwal VK, Higuera C, Deirmengian G, Parvizi J, Austin MS: Swab cultures are not as effective as tissue cultures for diagnosis of periprosthetic joint infection. Clin Orthop Relat Res 2013;471(10):3196-3203. Medline  DOI The study compared the yield of intraoperative tissue samples versus swab cultures in the diagnosis of PJI. Tissue cultures demonstrated higher sensitivity, specificity, positive predictive value, and negative predictive value than swab cultures. Swab cultures had more false-negative and false-positive results than tissue cultures, and their use in obtaining intraoperative culture specimens should be discouraged. Level of evidence: II. 62. Shanmugasundaram S, Ricciardi BF, Briggs TW, Sussmann PS, Bostrom MP: Evaluation and management of periprosthetic joint infection: An international, multicenter study. HSS J 2014;10(1):36-44. DOI This retrospective review of prospective registry data from 2008-2011 was done to determine the effectiveness of preoperative and intraoperative cultures to isolate organisms in cases of PJI. Preoperative synovial fluid aspiration yielded an organism in only 45.2% of knee PJI cases. False-negative rates of preoperative aspiration relative to intraoperative culture were 46% in knee PJI. Rates of negative intraoperative cultures were 20.7% in knee PJI. 63. Tischler EH, Cavanaugh PK, Parvizi J: Leukocyte esterase strip test: Matched for Musculoskeletal Infection Society criteria. J Bone Joint Surg Am 2014;96(22):1917-1920. Medline  DOI A retrospective review of prospective registry data from 2008-2011 was done to determine the effectiveness of preoperative and intraoperative cultures to isolate organisms in cases of PJI. Preoperative synovial fluid aspiration yielded an organism in only 45.2% of knee PJI cases. False-negative rates of preoperative aspiration relative to intraoperative culture were 46% in knee PJI. Rates of negative intraoperative cultures were 20.7% in knee PJI. 64. Deirmengian C, Kardos K, Kilmartin P, Cameron A, Schiller K, Parvizi J: Combined measurement of synovial fluid α-defensin and C-reactive protein levels: Highly accurate for diagnosing periprosthetic joint infection. J Bone Joint Surg Am 2014;96(17):1439-1445. Medline  DOI The presence of leukocyte esterase was prospectively evaluated in synovial joint aspirates from hips and knees. When matched to the current MSIS criteria, the leukocyte esterase strip test yielded a high specificity, positive predictive value, negative predictive value, and moderate sensitivity. The test should be considered an adjunct to the current battery of diagnostic tests available for PJI. 65. Bingham J, Clarke H, Spangehl M, Schwartz A, Beauchamp C, Goldberg B: The alpha defensin-1 biomarker assay can

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be used to evaluate the potentially infected total joint arthroplasty. Clin Orthop Relat Res 2014;472(12):40064009. Medline  DOI All patients undergoing workup for a PJI were retrospectively reviewed. Sixty-one alpha defensin-1 (AD-1) assays were done in 57 patients. The sensitivity and specificity of the AD-1 synovial fluid assay was compared with the synovial fluid cell count, culture, erythrocyte sedimentation rate, and C-reactive protein level. The sensitivity and specificity of the synovial fluid AD-1 assay exceeded the sensitivity and specificity of the other currently available clinical tests evaluated but did not reach significance. Level of evidence: III (diagnostic). 66. Frangiamore SJ, Gajewski ND, Saleh A, Farias-Kovac M, Barsoum WK, Higuera CA: α-Defensin accuracy to diagnose periprosthetic joint infection:Best available test? J Arthroplasty 2016;31(2):456-460. Medline  DOI This prospective study tested the diagnostic accuracy of α-defensin for PJI in revision THA and TKA. For firststage and single-stage revisions, the α-defensin test had a sensitivity of 100% (95% CI, 86%-100%) and a specificity of 98% (95% CI, 90%-100%) with a positive predictive value of 96% (95% CI, 80%-99%) and negative predictive value of 100% (95% CI, 93%-100%). Level of evidence: III. 67. Cooper HJ, Della Valle CJ: Advances in the diagnosis of periprosthetic joint infection. Expert Opin Med Diagn 2013;7(3):257-263. Medline  DOI The authors outline an algorithmic approach for diagnosis of PJI. Emerging technology is reviewed, including advanced imaging, serum markers, synovial fluid biomarkers, and point-of-care modalities.

The study used Medicare data of 1,493,924 primary TKAs performed between 2005 and 2011 to determine the incidence of subsequent reinfections after initial treatment of an infected TKA. PJI was diagnosed in a total of 16,622 patients (1.1%). The Kaplan-Meier risk of PJI was 0.77% at 1 year and 1.58% at 6 years. After first-line treatment, 26% of patients with PJI had a subsequent PJI. Patients undergoing irrigation and débridement as a first-line treatment had the highest risk of reinfection, with risks of 28.2% at 1 year and 43.2% at 6 years. Patients in the one-stage revision group had 33.9% greater adjusted risk of reinfection than patients in the two-stage revision group (P