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Atlas of Interventional Orthopedics Procedures

Atlas of Interventional Orthopedics Procedures

Essential Guide for Fluoroscopy and Ultrasound-Guided Procedures

Chris J. Williams, MD

Adjunct Professor

Emory Rehabilitation Department Emory University, Atlanta Georgia USA

CEO/Owner

Interventional Orthopedics of Atlanta, Atlanta Georgia USA

Walter I. Sussman, DO

Assistant Clinical Professor Physical Medicine & Rehabilitation Tufts University, Boston Massachusetts USA

John Pitts, MD

Fellowship Director

Interventional Orthopedics

Centeno- Schultz Clinic, Broomfield Colorado USA

© 2023, Elsevier Inc. All rights reserved.

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This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).

Notices

Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made. To the fullest extent of the law, no responsibility is assumed by Elsevier, authors, editors, or contributors for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein.

ISBN: 978-0-323-75514-6

Content Strategist: Humayra Khan

Content Development Specialist: Kim Benson/Grace Onderlinde

Project Manager: Andrew Riley

Design: Patrick Ferguson

Illustration Manager: Muthukumaran Thangaraj

Illustrator: Dr Patrick Nguyen

Marketing Manager: Kate Bresnahan

Foreword vii

Preface viii

Editor Biographies x

Contributors xii

Acknowledgments xx

Section I Introduction

1 Introduction to Interventional Orthopedics and Review of the Pathophysiology of Orthopedic Conditions, 1

Walter I. Sussman, John Pitts, and Chris Williams

2 Ultrasound Basics, 14

Matthew Sherrier, Allison N. Schroeder, Kentaro Onishi, and Daniel Lueders

3 Principles of Fluoroscopy Imaging in Spine and Musculoskeletal Interventional Orthopedics, 31

Katarzyna Iwan, Rahul Naren Desai, and John J. Wolfson

Section II Injectates

4 Principles of Injection Therapy, 41

Lee Kneer, Robert Bowers, and Cleo D. Stafford II

5 Autologous Tissue Harvesting Techniques: Bone Marrow Aspirate and Adipose Tissue, 50

Gerard Malanga, Jay E. Bowen, and Selorm L. Takyi

6 Autologous Tissue Harvesting Techniques: Platelet-Rich Plasma, 62

Peter A. Everts

7 Autologous Orthobiologics, 70

Prathap Jayaram, Peter Chia Yeh, Max Epstein, and Shiv J. Patel

8 Allograft Tissues, 89

Alberto J. Panero, Alan M. Hirahara, Luga Podesta, Amir A. Jamali, Wyatt Andersen, and Alyssa A. Smith

9 Therapeutic Dextrose Injection: Prolotherapy, Perineural Injection Therapy, and Hydrodissection, 102

Kenneth D. Reeves, Stanley K.H. Lam and David Rabago

10 Sclerosing Agents, 118

Colton L. Wood, David J. Berkoff, and Justin R. Lockrem

11 Toxins for Orthopedics, 124

Zach Bohart, Walter I. Sussman, Jacob Sellon, and Natalie Sajkowicz

Section III Atlas

12 Cervical Injection Techniques, 134

Marko Bodor, Stephen Derrington, John Pitts, Jason Markle, Sairam Atluri, Navneet Boddu, and Vivek Manocha

13 Thoracic Injection Techniques, 166

Marko Bodor, Stephen Derrington, John Pitts, Jason Markle, and Orlando Landrum

14 Lumbar Injection Techniques, 186

Di Cui, Lisa Foster, Brian Hart Keogh Jr., Jason Markle, Hassan Monfared, Jaymin Patel, Shounuck I. Patel, John Pitts, and Diya Sandhu

15 Sacrococcygeal Injection Techniques, 224

Joanne Borg-Stein, Catherine Mills, Carolyn Black, Oluseun Olufade, and Giorgio A. Negron

16 Shoulder Injection Techniques, 242

Jason Markle and Cleo D. Stafford II

17 Elbow Injection Techniques, 272

Chris Williams, Walter I. Sussman, and John Pitts

18 Wrist Injection Techniques, 290

Kevin Conley, Yoditi Tefera, Michael Erickson, Adam M. Pourcho, Phillip Henning, and Oluseun Olufade

19 Hand Injection Techniques, 313

Yodit Tefera, Kevin Conley, Michael Erickson, Adam M. Pourcho, Phillip Henning, and Oluseun Olufade

20 Hip Injection Techniques, 323

Ken Mautner, John Pitts, Oluseun Olufade, Heather Lynn

Saffel, and Adam Street

21 Knee Injection Techniques, 366

Josh Hackel, Todd Hayano, John Pitts, and Mairin A. Jerome

22 Ankle Region Injection Techniques, 428

Allison C. Bean, Allison N. Schroeder, Matthew Sherrier, Arthur Jason de Luigi, and Kentaro Onishi

23 Foot Injection Techniques, 465

Douglas Hoffman, Jacob Jones, Pierre D’hemecourt, John Pitts, and Arthur Jason De Luigi

Section IV Advanced

24 Calcific Tendonitis Barbotage/Lavage, 489

Jason Ian Blaichman and Kenneth S. Lee

25 High-Volume Ultrasound-Guided Capsular Distention for Adhesive Capsulitis, 496

Alyssa Neph Speciale and Brian Davis

26 Ultrasound-Guided Needle Tenotomy and Ultrasound-Guided Tenotomy and Debridement With Tenex Health TX System, 502

Ryan C. Kruse and Mederic M. Hall

27 High-Volume Image-Guided Injections, 506

Maria-Cristina Zielinski, Nicola Maffulli, Otto Chan, and Romain Haym

28 Ultrasound-Guided Release of Trigger Finger and de Quervain Tenosynovitis, 514

Ricardo E. Colberg and Javier A. Jurado

29 Compartment Pressure Testing, 524

Jonathan T. Finnoff and Jacob Reisner

30 Ultrasound-Guided Anterior and Lateral Compartment Fasciotomies for Chronic Exertional Compartment Syndrome, 527

Jonathan T. Finnoff and Jacob Reisner

31 Principles of Perineural Injections, 531

Jeffrey A. Strakowski

32 Ultrasound-Guided Release of the Transverse Carpal Ligament (Carpal Tunnel), 535

Adam M. Pourcho, Phillip Henning, and Jay Smith

33 Ultrasound-Guided Percutaneous Bone Spur Excision and Cheilectomy, 544

Brian J. Shiple

34 Intraosseous Injections, 553

Steven Sampson, Hunter Vincent, and Sonali Lal

35 Advanced and Emerging Interventional Techniques, 573

Nidal Elbaridi, Virlyn Bishop, Orlando Landrum, Marko Bodor, and John Pitts

36 Needle Arthroscopy of the Knee, Shoulder, and Hip, 594

Don Buford, Brice W. Blatz, and Nicola Hyde

Section V Postprocedure Considerations

37 Rehabilitation Principles for Interventional Orthopedics and Orthobiologics, 599

Walter I. Sussman, Ken Mautner, and Abby Perone

38 Advanced Imaging in Interventional Orthopedics, 612

Rahul Naren Desai and Katarzyna Iwan

Foreword

In the early 2000s, I was frustrated with interventional spine care. We were performing imaging-guided corticosteroid injections in the spine as well as radiofrequency ablation and could help many patients, but these were often “Bandaid” procedures. The same held true for the corticosteroid or hyaluronic acid injections we could offer in peripheral joints for osteoarthritis. Then a 2004 article was published showing that a rabbit disc could be regenerated with an injection of mesenchymal stem cells (MSCs) and my mind exploded. By 2005, we had begun an IRB-approved clinical trial using cultured bone marrow MSCs in the intervertebral disc and in various peripheral joints.

As we treated patients, we began to realize that what we had learned in interventional spine was only a small part of what was possible. For example, when tissue regeneration or healing is possible, placing stem cells or platelets using ultrasound or fluoroscopy into specific damaged structures of the musculoskeletal system is the goal. However, it soon became clear that there were several limitations to the possibilities of treating musculoskeletal injuries. For example, there were no interventional spine courses or texts that discussed how to inject a damaged knee anterior cruciate ligament (ACL), shoulder labrum, or ankle ligament.

Additionally, the diagnostic and therapeutic approach to these issues was entirely different than interventional spine or orthopedic surgery. For example, interventional spine had nothing to say about how to diagnose an ACL tear or which tears would be appropriate for injection-based regenerative medicine versus which ACL tears would be more appropriate for traditional surgical reconstruction. While orthopedic surgery had a diagnostic approach, it was focused on a binary decision, which is whether the damaged ACL should be surgically removed and replaced or not.

Hence, it was clear based on the techniques required and the different diagnostic and therapeutic approach that this was

a new medical specialty. Consequently, the concept of interventional orthopedics was born. Our clinic soon set up a fellowship program to educate physicians as well as a non-profit organization, the Interventional Orthopedics Foundation (IOF). The primary goal of the IOF was to train physicians in the United States and abroad with a background in musculoskeletal care how to precisely inject structures under image guidance with hands-on didactic sessions.

Looking back, I realize that this textbook is the culmination of both the problem of a limited set of treatment options for musculoskeletal injuries and the dream of bridging non-operative and operative orthopedic care with precision-based interventional orthopedics. In other words, a new interventional specialty needs standard texts that describe the core procedures of that specialty. As radical as this concept may seem, there is nothing new under the sun, as the phrase goes. Medicine witnessed a similar specialty emergence and transition in paradigm from a more surgical model of cardiovascular care with the inception of interventional cardiology in the late 1980s.

This textbook includes contributions from many of the leaders in the field and several physicians that have completed a fellowship in interventional orthopedics and completed hundreds of didactic hours staying up to date on emerging techniques and new research. This willingness to be an innovator and disrupter in the field is necessary for laying the foundation of stones to the metaphorical building, which will continue to cement the legitimacy of this new medical specialty. I applaud and 100% support their efforts and happily pass the torch to that next generation.

Christopher J. Centeno, MD

Preface

Evolution

“The only constant in life is change”

—HERACLITUS

Musculoskeletal medicine is currently undergoing a paradigm shift as alternatives to the traditional approaches of care are being investigated vigorously by clinicians, scientists, and patients. Conventional methods utilizing anatomic landmarks for injection-based therapy have slowly been replaced by precision-guided injections at the pointof-care with high-definition ultrasound and fluoroscopy. Long-established surgical procedures are being substituted for minimally invasive techniques without having a negative impact on patient outcomes.

All the procedure techniques described in this book are image guided and we believe this to be the standard of care at this time. Topics covered range from simple ultrasoundguided joint injections, ligament and tendon injections, perineural hydrodissection, fluoroscopically guided spine procedures, and advanced microinvasive surgical procedures—such as minimally invasive carpal tunnel release, A1 pulley/trigger finger release, intraosseous subchondral injections, calcific tendinopathy debridement, and the TENEX procedure, to name a few.

Inception

“An Idea Is Like A Virus.”

—CHRISTOPHER NOLAN

The idea of this book came about as the authors were collecting fluoroscopic and ultrasound-guided images of structures to perfect new injections techniques and for educating doctors in training as well. We began collecting images showing desired contrast flow patterns for structures such as the ACL, PCL, spine ligaments, shoulder labrum, and the hip ligamentum teres. During this process, we realized that the majority of the techniques are not widely known and only a handful of courses were offered to teach some of the advanced techniques sporadically throughout the year. The idea was then born to create an inclusive “atlas” incorporating both ultrasound- and fluoroscopy-guided musculoskeletal procedures. Additionally, we wanted to include an up-to-date resource on the current research and clinical outcomes for orthobiologics given the overwhelming utilization by many clinicians.

With the advent and growing evidence for the use of orthobiologics in orthopedic medicine, we realized these substances could be injected in far more tissue areas than the traditional steroids and local anesthetics. Because these substances can be used to treat joints, bursae, fibrocartilage structures, tendons, ligaments, muscles, bones, and perineurally, they open up a whole new world of procedures that were previously not described. Thus, the pioneers of these treatments had to discover or invent new ways to inject these substances safely and accurately into tissues one would not typically treat with steroids only.

Blueprint

“Reading is the foundation of learning but an artist drew up the blueprints.”

—GEORGE E. MILLER

“Of what use is a dream if not a blueprint for courageous action.”

—ADAM WEST

We have been fortunate to have the opportunity to learn, advance, and create many of these techniques we learned from pioneers in this field, such as Chris Centeno, John Schultz, and Kenneth Mautner to name a few.

This atlas provides a systematic approach for injecting all the relevant structures that are commonly encountered by non-operative sports medicine and interventional spine physicians. The primary goal was to provide a single text that an injectionist could utilize throughout the spectrum of learning and practicing.

Section I of the book introduces the basics of image guidance. Section II discusses the background and evidence for the most commonly used injectates and orthobiologics available at the time of writing this text. Section III is the bulk of the text and describes ultrasound- and fluoroscopyguided procedures separated by body region. We provide relevant anatomy and pathology and describe a step-by-step guide for the injectionist to utilize as a supplemental learning tool for hands-on training. Section IV provides evidence and descriptions for more advanced procedures that can aide the more experienced interventional orthopedist and should not be attempted until significant hands-on experience has been completed. Finally, Section V starts with a chapter on postprocedure rehabilitation principles and

current evidence. It concludes with a chapter on imaging, with visual examples demonstrating various degrees of tissue healing and regeneration.

Ideally, this text will serve as a fluid reference point as procedural techniques and injectate options continue to evolve.

Making this book has expanded our thought process and clinical knowledge, and we sincerely hope that the readers

of this book experience the same. Our hope is to further advance the field of interventional orthopedics and regenerative medicine and inspire the next generation to take the field further.

Chris J. Williams, MD

Walter I. Sussman, DO John Pitts, MD

Editor Biographies

Chris J. Williams, MD

Christopher J. Williams, MD, was born and raised in Jacksonville, Florida. After high school, Dr. Williams entered the US Air Force and worked as a public health technician in England, Kuwait, and Mississippi. After serving 4 years in the Air Force, he decided to get his undergraduate degree from the University of North Florida, where he graduated summa cum laude. He then opted to attend medical school at Emory University where he also completed his residency training in physical medicine and rehabilitation. During residency, he was awarded the Resident of Year award for all 3 years of his residency training and was Chief Resident his last year of training. During residency, Dr. Williams spearheaded the development of a musculoskeletal (MSK) ultrasound training curriculum and started a prosthetics and orthotics annual symposium in collaboration with Georgia Tech.

Dr. Williams is board certified in physical medicine and rehabilitation and completed fellowship training in interventional orthopedics and regenerative medicine for 1 year at the Centeno-Schultz Clinic in Broomfield, CO. After completing his training, he was an attending physician at the Centeno-Schultz Clinic prior to opening his practice in Atlanta, GA: Interventional Orthopedics of Atlanta. In collaboration with Ken Mautner at Emory, they started a joint non-accredited fellowship program in interventional orthopedics and graduated their first fellow in July 2020.

Education is one of his passions, as he was raised by a very hardworking single parent who was also a teacher and instilled in him the principles of humility, hard work, and dedication. Currently, Dr. Williams is an adjunct faculty member at Emory University in the Department of Rehabilitation Medicine, providing didactics annually and also allowing the residents to get hands-on training while rotating with him during their elective time. He is an instructor and the educational committee co-chair for the Interventional Orthobiologics Foundation, teaching several courses annually. He also has lectured at the annual conference for The Orthobiologics Institute (TOBI).

Dr. Williams has published over 10 peer-reviewed research articles and book chapters on the topics of orthobiologics and rehabilitation medicine. He achieved best-selling author status on Amazon for his book Exercise 2.0 and was recognized by Emory University Alumni Association 40 Under 40 in 2019.

In his private practice at the Interventional Orthopedics of Atlanta, Dr. Williams specializes in the diagnosis

and treatment of musculoskeletal conditions in athletes, weekend warriors, adolescents, the underserved, and the elderly. He strives to provide exceptional care to everyone he encounters.

Dr. Williams resides in Atlanta, Georgia with his wife Layla, who is an ObGyn physician; two children, Kemet and Egypt; and enjoys cooking, fitness activities, art, music, and traveling.

Walter I. Sussman, DO

Dr. Walter I. Sussman is board certified in physical medicine and rehabilitation with fellowship training in sports medicine. He completed his undergraduate studies at Colgate University and medical school at the University of New England College of Osteopathic Medicine in Biddeford, Maine. During medical school, he completed a 1-year fellowship in anatomy and osteopathic manipulative medicine. He completed his residency in physical medicine and rehabilitation at Emory University, where he served as chief resident. He then pursued a fellowship in sports medicine at Emory University, where he provided coverage for the Atlanta Dream WNBA team, Georgia Tech athletics, and Emory University athletics.

Dr. Sussman currently works in private practice outside of Boston and serves as the Head Team Physician for the University of Massachusetts Dartmouth and provides care for many of the local high schools. He is a clinical Assistant Professor at Tufts University and is engaged in resident education. Dr. Sussman has published multiple book chapters and peer-reviewed articles on regenerative medicine, chronic tendon injuries, diagnostic musculoskeletal ultrasound, and concussion management.

Dr. Sussman takes pride in promoting the patient experience and individualizing the treatment to fit each patient. Dr. Sussman has a clinical interest in the use of ultrasound to diagnose musculoskeletal injuries, in post-concussion syndrome, in orthobiologics, and in minimally invasive procedures. Dr. Sussman manages chronic musculoskeletal conditions, acute sports injuries, and sports-related concussions.

John Pitts, MD

John Pitts, MD, was born and raised on the south side of Chicago, IL. He received a BA in Mathematics/Economics at Emory University in Atlanta, Georgia. Dr. Pitts received his medical education at Vanderbilt School of Medicine

in Nashville and then completed a physical medicine and rehabilitation residency back at Emory University. After residency he completed a 1-year fellowship (non-accredited) in regenerative medicine and interventional orthopedics at the Centeno - Schultz Clinic, where he works currently and is part of the Regenexx network of physicians. He serves as the fellowship director and helps to train new Regenexx physicians. He also regularly teaches procedural courses for the Interventional Orthopedics foundations and has given presentations at major conference for the American Academy of Physical Medicine and Rehabilitation (AAPMR), The Orthobiologics Institute (TOBI), and the American Association of Orthopedic Medicine (AAOM).

Dr. Pitts has been practicing regenerative Medicine and interventional orthopedics exclusively since 2013. He diagnoses and treats patients with a variety of orthopedic and musculoskeletal problems, including spine (cervical, thoracic, lumbar, sacroiliac joints), temporomandibular joint, upper extremity (shoulder, elbow, wrist, hand, fingers), lower extremity (hip, knee, ankle, foot, toes), and problems relating to peripheral

nerves, joints, ligaments, tendons, bones, and muscle. He regularly uses orthobiologics such as prolotherapy, neuroprolotherapy, platelet-rich plasma (PRP), platelet lysate, bone marrow concentrate, micronized adipose tissue graft, and amniotic membrane. Additionally, he works in Grand Cayman Island several times per year, where he is able to treat patients with cultured expanded bone marrow mesenchymal stem cells (MSCs). He utilizes other devices to be used in interventional orthopedics and helps to pioneer and advance many of the procedures.

Dr. Pitts has co-authored several peer-reviewed articles relating to regenerative treatments. He also authored a book named Nutrition 2.0, Guide to Eating and Living to Achieve a Higher Quality of Life Now and into Your Golden Years, and gives this to all his patients.

Dr. Pitts resides in Denver, CO, with his wife, Ria, and two young children, Malcolm and Camila. He enjoys working out, playing sports, snowboarding, scuba diving, being outdoors, traveling, watching movies, and spending time with his family.

Contributors

Associate Editors

Marko Bodor, MD Founder

Interventional Spine and Sports Medicine Bodor Clinic Napa, California USA

Assistant Professor

Physical Medicine and Rehabilitation University of California Davis Sacramento, California USA

Assistant Professor Neurological Surgery University of California San Francisco San Francisco, California USA

Don Buford, MD, RMSK Orthopedic Surgeon Sports Medicine

Texas Orthobiologic Institute Dallas, Texas USA

Rahul Naren Desai, MD CEO

Musculoskeletal Radiology Restore

PDX Spine & Sports Medicine Beaverton, Oregon USA

President

Interventional Orthopedic Foundation Broomfield, Colorado USA

Gerard Malanga, MD Partner

New Jersey Sports Medicine, LLC Cedar Knolls, New Jersey USA

Clinical Professor PM&R

Rutgers Medical School Newark, New Jersey USA

Jason Markle, DO Interventional Orthopedic Physician Orthopedics

The Centeno-Schultz Clinic Broomfield, Colorado USA

Ken Mautner, MD Assistant Professor

Physical Medicine & Rehabilitation Emory University, Atlanta USA

Contributors

Wyatt Andersen, BS, ATC Research Assistant Physical Medicine & Rehabilitation Sacramento, California USA

Sairam Atluri, MD Medical Director ReGen StemCures Cincinnati, Ohio USA

Allison C. Bean, MD, PhD Department of Physical Medicine and Rehabilitation University of Pittsburgh Medical Center Pittsburgh, Pennsylvania USA

David J. Berkoff, MD Professor Orthopedics and Emergency Medicine UNC Chapel Hill Chapel Hill, North Carolina USA

Virlyn Bishop Anesthesiology and Pain Medicine Center for Spine Interventions Acworth, GA USA

Carolyn Black, MD, PhD

Resident Physician

Physical Medicine and Rehabilitation

Harvard Medical School/Spaulding Rehabilitation Hospital

Boston, Massachusetts USA

Jason Ian Blaichman, MDCM, FRCPC

Adjunct Lecturer

Department of Medical Imaging

University of Toronto Toronto, Ontario

Canada

Staff Radiologist

Department of Diagnostic Imaging

Scarborough Health Network Scarborough, Ontario Canada

Brice W. Blatz, MD, MS

Physician/Owner

Sports and Regenerative Medicine

Pacific Regenerative and Interventional Sports Medicine

San Jose, California USA

Navneet Boddu, MD

Anesthesiologist

Anesthesiology

Anesthesia Service Medical Group

San Diego, California USA

Marko Bodor, MD Founder

Interventional Spine and Sports Medicine Bodor Clinic

Napa, California USA

Assistant Professor

Physical Medicine and Rehabilitation

University of California Davis Sacramento, California USA

Assistant Professor

Neurological Surgery

University of California San Francisco San Francisco, California USA

Zach Bohart, MD, MS

Associate Professor

Tufts University School of Medicine

Boston, Massachusetts USA

Joanne Borg-Stein, MD

Associate Professor

Physical Medicine and Rehabilitation

Harvard Medical School

Boston, Massachusetts USA

Jay E. Bowen, DO

Medical Director

New Jersey Regenerative Institute, LLC

Cedar Knolls, New Jersey

USA Clinical Assistant Professor PM&R, Rutgers Medical School, New Jersey USA

Robert Bowers, DO, PhD

Assistant Professor

Department of Orthopaedics

Emory University School of Medicine

Atlanta, Georgia USA

Assistant Professor

Department of Rehabilitation Medicine

Emory University School of Medicine

Atlanta, Georgia USA

Don Buford, MD, RMSK

Orthopedic Surgeon

Sports Medicine

Texas Orthobiologic Institute Dallas, Texas USA

Christopher J. Centeno, MD

Research and Development

Regenexx, LLC

Broomfield, Colorado USA

Centeno-Schultz Clinic Broomfield, Colorado USA

Otto Chan, MBBS, FRCS, FRCR Doctor

Radiology Department

Whittington Hospital London United Kingdom

Ricardo E. Colberg, MD, RMSK

Sports Medicine Physician

Andrews Sports Medicine & Orthopaedic Center Birmingham, Alabama USA

Kevin Conley, MD

Fellow

Swedish Sports & Spine

Providence-Swedish Health Alliance Seattle, Washington USA

Di Cui, MD

Assistant Professor

Department of Rehabilitation Emory University Atlanta, Georgia USA

Brian Davis, MD, FACSM

Volunteer Clinical Professor

Department of Physical Medicine & Rehabilitation

UC Davis Health System, Sacramento California USA

Arthur Jason De Luigi, DO Chair

Physical Medicine & Rehabilitation

Mayo Clinic Arizona Scottsdale, Arizona USA

Professor of Rehabilitation Medicine

Rehabilitation Medicine

Georgetown University School of Medicine Washington, District of Columbia USA

Associate Professor of Physical Medicine & Rehabilitation

Physical Medicine & Rehabilitation Mayo Clinic Alix School of Medicine Scottsdale, Arizona USA

Stephen Derrington, DO

President and Medical Director

Interventional Orthobiologics

Derrington Orthopedics – Interventional Sports and Spine Oceanside and Laguna Hills, California USA

Rahul Naren Desai, MD

CEO

Musculoskeletal Radiology

RestorePDX Spine & Sports Medicine Beaverton, Oregon USA

President Interventional Orthopedic Foundation Broomfield, Colorado USA

Pierre D’Hemecourt, MD Physician

Sports Medicine

Boston Children’s Hospital Boston, Massachusetts USA

Nidal Elbaridi, MD, PT

Medical Director

Interventional Pain Loop Medical Center Chicago, Illinois USA

Max H. Epstein, MD

Resident

Physical Medicine & Rehabilitation

Baylor College of Medicine Houston, Texas USA

Michael Erickson, MD

Swedish Sports Medicine Fellowship Director

Swedish Family Medicine Residency Swedish Medical Center Seattle, Washington USA

Clinical Instructor

Family Medicine University of Washington Seattle, Washington USA

Peter A. Everts, PhD, FRSM

Chief Scientific Officer EmCyte Program Director Gulf Coast Biologics Fort Myers. Florida USA

Jonathan T. Finnoff, DO, FAMSSM, FACSM

Chief Medical Officer

United States Olympic and Paralympic Committee, Colorado Springs Colorado USA

Professor

Department of Physical Medicine and Rehabilitation

Mayo Clinic College of Science and Medicine, Rochester Minnesota USA

Lisa Foster, MD

Assistant Professor Orthopedics

Emory University

Atlanta, Georgia USA

Josh Hackel, MD, RMSK, CAQSM

Fellowship Director USA/Andrews Research and Education Foundation

Primary Care Sports Medicine

Andrews Institute

Gulf Breeze, Florida USA

Mederic M. Hall, MD

Associate Professor

Orthopaedics and Rehabilitation University of Iowa Iowa City, Iowa USA

Todd Hayano, DO

Sports Medicine Fellow

Orthopedics & Sports Medicine

Andrews Research & Education Foundation

Pensacola, Florida USA

Romain Haym, MSc (MSK Ultrasound), MSc (Adv. Physiotherapy), MHCPC, MCSP, MMACPC

Tendon Clinic—Senior Physiotherapist Physiotherapy

BMI The London Independent Hospital, London

United Kingdom

MSK Sonographer Imaging

NHS Whittington Trust, London United Kingdom

Phillip Henning, DO

Medical Director of Sports Medicine

Rehabilitation and Performance Medicine

Swedish Medical Center, Seattle, Washington USA

Alan M. Hirahara, MD, FRCSC

Owner

Private Practice Sacramento, California USA

Douglas Hoffman, MD

Director of Musculoskeletal Ultrasound

Orthopedics and Radiology

Essentia Health

Duluth, Minnesota USA

Nicola Hyde

Sports Medicine and Family Medicine Physician

Seattle, Washington USE

Katarzyna Iwan, MD Doctor

Pain Medicine

RestorePDX

Beaverton, Oregon USA

Amir A. Jamali, MD

Medical Director

Orthopaedic Surgery

Joint Preservation Institute Walnut Creek, California USA

Prathap Jayaram, MD Director of Regenerative Sports Medicine

H. Ben Taub Physical Medicine & Rehabilitation

Department of Orthopedic Surgery

Baylor College of Medicine

Houston, Texas USA

Mairin A. Jerome, MD Fellow

Interventional Orthopedics Centeno-Schultz Clinic Broomfield, Colorado USA

Jacob Jones, MD Physician

Orthopedics and Sports Medicine

Boston Children’s Hospital Boston, Massachusetts USA

Javier A. Jurado

Medical Student

The University of Alabama at Birmingham School of Medicine Birmingham, Alabama USA

Brian Hart Keogh Jr., MD

East Carolina Pain Consultants

Interventional Pain Management

Vidant Medical Center

Greenville, North Carolina USA

Affiliate Clinical Faculty Department of Physical Medicine and Rehabilitation

East Carolina University School of Medicine

Greenville, North Carolina USA

Lee Kneer, MD FAAPMR

Assistant Professor

Department of Orthopaedics

Emory University School of Medicine, Atlanta

Georgia USA

Assistant Professor

Department of Rehabilitation Medicine

Emory University School of Medicine, Atlanta

Georgia USA

Ryan C. Kruse, MD, CAQSM, RMSK

Assistant Professor

Orthopedics and Rehabilitation University of Iowa Iowa City, Iowa USA

Sonali Lal, MD

Assistant Professor, Columbia University

Attending Physician, New York

Presybyterian Hospital

Stanley K. H. Lam, MBBS, MScSEM, FHKIMM, RMSK, CIPS, FIPP, POCUS

President

Clinical Research

The Hong Kong Institute of Musculoskeletal Medicine

Kowloon Bay

Hong Kong

Clinical Associate Professor

Family Medicine

The Chinese University of Hong Kong

New Territory

Hong Kong

Clinical Assistant Professor

Family Medicine

The University of Hong Kong

Hong Kong

Orlando Landrum, MD, MBA

Physician CEO

Pain & Regenerative Medicine

Cutting Edge Integrative Pain Centers

Elkhart, Indiana

USA

Kenneth S. Lee, MD/MBA Professor of Radiology

Section Chief of Musculoskeletal Imaging & Intervention Fellowship Director

Musculoskeletal Imaging & Intervention

University of Wisconsin School of Medicine and Public Health

Madison, Wisconsin

USA

Justin R. Lockrem, MD

Sports Medicine Fellow

Sports Medicine

University of North Carolina Chapel Hill, North Carolina USA

Daniel Lueders, MD

Assistant Professor

Physical Medicine and Rehabilitation

University of Pittsburgh Medical Center Pittsburgh, Pennsylvania USA

Nicola Maffulli, MD, MS, PhD, FRCP, FRCS(Orth)

Full Professor

Medicine, Surgery and Dentistry

University of Salerno

Salerno Italy

Gerard Malanga, MD Partner

New Jersey Sports Medicine, LLC Cedar Knolls, New Jersey USA

Clinical Professor PM&R

Rutgers Medical School Newark, New Jersey USA

Vivek Manocha, MD

Medical Director

Pain Management

Midwest Spine Interventionalist Springboro, Ohio USA

Clinical Assistant Professor Surgery

Wright State University Boonshoft School of Medicine

Dayton, Ohio USA

Jason Markle, DO

Interventional Orthopedic Physician Orthopedics

The Centeno-Schultz Clinic Broomfield, Colorado USA

Ken Mautner, MD

Assistant Professor

Physical Medicine & Rehabilitation

Emory University, Atlanta USA

Catherine Mills, MD

Resident Physician

Physical Medicine & Rehabilitation

Harvard Medical School/Spaulding Rehabilitation Hospital Boston, Massachusetts USA

Hassan Monfared, MD

Assistant Professor

Physical Medicine and Rehabilitation Emory University Atlanta, Georgia USA

Residency Program Director

Physical Medicine and Rehabilitation Emory University Atlanta, Georgia USA

Giorgio A. Negron, MD

Resident Physician

Department of Rehabilitation Medicine Emory University Atlanta, Georgia USA

Oluseun Olufade, MD

Assistant Professor Department of Orthopedics

Emory School of Medicine Atlanta, Georgia USA

Assistant Professor

Department of Physical Medicine & Rehabilitation Emory School of Medicine Atlanta, Georgia USA

Kentaro Onishi

Assistant Professor Physical Medicine and Rehabilitation University of Pittsburgh Medical Center, Pittsburgh Pennsylvania USA

Alberto J. Panero, DO http://sacsportsmed.com

Sports Medicine

SAC Regenerative Orthopedics Sacramento, California USA

Jaymin Patel, MD

Assistant Professor Orthopaedics

Emory University Atlanta, Georgia USA

Shiv J. Patel, MD Resident

Orthopaedic Surgery

University of Texas Medical Branch, Galveston Texas USA

Shounuck I. Patel, DO

Functional & Interventional Orthopedics

Spine & Sports Physiatry

Regenexx Los Angeles Los Angeles, California USA

Clinical Assistant Professor

College of Osteopathic Medicine of the Pacific Western University Pomona, California USA

Clinical Assistant Professor

College of Osteopathic Medicine Touro University Harlem, New York USA

Abby Perone, DC

Love Health, Owner Movement Therapy & Functional Medicine

St. Petersburg, Florida USA

John Pitts, MD

Fellowship Director Interventional Orthopedics Centeno-Schultz Clinic Broomfield, Colorado USA

Luga Podesta, MD Director

Regenerative Sports Medicine Bluetail Medical Group-Naples Naples, Florida USA

Team Physician Florida Everglades Estero, Florida USA

Adam M. Pourcho, DO

Instructor of Sports Medicine

Physical Medicine and Rehabilitation

Swedish Medical Group Seattle, Washington USA

David Rabago, MD

Associate Professor Department of Family Medicine

University of Wisconsin School of Medicine and Public Health

Madison, Wisconsin USA

Kenneth D. Reeves, BS, MD

Private Practice

Physical Medicine and Rehabilitation and Pain Management

Roeland Park, Kansas USA

Formerly Clinical Assistant/Associate Professor 1986–2015

Physical Medicine and Rehabilitation

University of Kansas Medical Center

Kansas City, Kansas USA

Jacob Reisner, DO

Primary Care Sports Medicine Fellow

Physical Medicine and Rehabilitation

Mayo Clinic

Minneapolis, Minnesota USA

Heather Lynn Saffel, MD, MS

Primary Care Sports Medicine Fellow Department of Orthopedics

Emory Sports Medicine Center

Atlanta, Georgia USA

Natalie Sajkowicz, MD Physician

Physical Medicine and Rehabilitation

Tufts Medical Center Boston, Massachusetts USA

Steven Sampson, DO

Founder

PM&R

The Orthohealing Center

Los Angeles, California USA

Founder

The Orthobiologic Institute Los Angeles, California USA

Clinical Instructor

Medicine

David Geffen School of Medicine UCLA Los Angeles, California USA

Diya Sandhu, MD

Assistant Professor Orthopaedics

Emory University

Atlanta, Georgia USA

Assistant Professor

Physical Medicine and Rehabilitation

Emory University

Atlanta, Georgia USA

Allison N. Schroeder, MD

Resident Physician

Physical Medicine and Rehabilitation University of Pittsburgh Medical Center Pittsburgh, Pennsylvania USA

Jacob Sellon, MD

Associate Professor

Physical Medicine and Rehabilitation/Sports Medicine Center

Mayo Clinic

Rochester, Minnesota USA

Matthew Sherrier, MD

Resident Physician

Physical Medicine and Rehabilitation University of Pittsburgh Medical Center Pittsburgh, Pennsylvania USA

Brian J. Shiple, DO, CAQSM, RMSK

President AAOM

Board Certified Sports Medicine

The Center for Sports Medicine Philadelphia, Pennsylvania USA

Alyssa A. Smith, BSc Medical Assistant

Joint Preservation Institute, Sacramento, California USA

Jay Smith, MD

Professor

Physical Medicine & Rehabilitation

Mayo Clinic

Rochester, Minnesota USA

Alyssa Neph Speciale, MD

Assistant Clinical Professor, PM&R Sports Medicine

UC Davis Health System

Sacramento, California USA

Cleo D. Stafford II, MD, MS, CAQSM, RMSK, FAAPMR

Assistant Professor

Department of Orthopaedics

Emory University School of Medicine, Atlanta Georgia USA

Assistant Professor

Department of Rehabilitation Medicine

Emory University School of Medicine, Atlanta Georgia USA

Jeffrey A. Strakowski, MD

Clinical Professor

Physical Medicine and Rehabilitation

The Ohio State University Columbus, Ohio USA

Associate Director of Medical Education

Physical Medicine and Rehabilitation

Riverside Methodist Hospital Columbus, Ohio USA

Director of Musculoskeletal Research

The McConnell Spine, Sport and Joint Center Columbus, Ohio USA

Adam Street, BS, DO Fellow

Emory Sports Medicine Center

Emory University Atlanta, Georgia USA

Walter I. Sussman, DO

Assistant Clinical Professor

Physical Medicine & Rehabilitation

Tufts University Boston, Massachusetts USA

Selorm L. Takyi, MD

Regenerative Orthopedics and Musculoskeletal Medicine Physician

Physical Medicine & Rehabilitation

Revive Spine and Pain Center, Marlton

New Jersey USA

Yodit Tefera, MD

Physician

Swedish Spine, Sports, & Musculoskeletal Medicine

Swedish Medical Center

Seattle, Washington USA

Hunter Vincent, DO

Pain Fellow

Physical Medicine and Rehabilitation

University of California: Los Angeles

Los Angeles, California USA

Chris J. Williams, MD

Adjunct Professor

Emory Rehabilitation Department

Emory University

Atlanta, Georgia USA

CEO/Owner

Interventional Orthopedics of Atlanta Atlanta, Georgia USA

John J. Wolfson, RT (R), ASRT, (ARRT)

Imaging and Interventional Coordinator OR

Injury Solutions

Greenwood Village, Colorado USA

Instructor

Pain Imaging Education Englewood, Colorado USA

Colton L. Wood, MD

Primary Care Sports Medicine Fellow

Family Medicine

University of North Carolina at Chapel Hill

Chapel Hill, North Carolina USA

Peter Chia Yeh, MD

Chief Resident

Physical Medicine and Rehabilitation

Baylor College of Medicine

Houston, Texas USA

Maria-Cristina Zielinski, MD, PGDip, PGCert, AECC

Centre for Sports and Exercise Medicine

Barts and The London School of Medicine

Queen Mary University of London London, UK

Acknowledgments

A huge thank you is well deserved for my wife, who has been patient and very supportive during the completion of this atlas. My siblings and the community I grew up in continue to serve as major inspiration for me. Additionally, my fellow associate editors John Pitts and Walter Sussman have made an almost gargantuan task as seamless and tolerable as possible. The contributing authors have been great to work with and their expertise is appreciated. A special thank you to all of the associate editors as well; I consider all of you as leaders in the field and most of you have served as a mentor for me at some point. Prior to starting PM&R residency at Emory University, I had no idea orthobiologics existed. I definitely owe an additional huge thank you to John Pitts, who is largely responsible for introducing me to orthobiologics and providing excellent training during my Fellowship at the Centeno-Schultz Clinic, which served as ground zero for the development and fine tuning of many of these procedural techniques. Last but not least, thank you to Elsevier for seeing the vision for the atlas and definitely the readers, who will ultimately lead to the continued evolution of the field.

Chris Williams, MD

I would first like to thank my wife for allowing me the extra time required to edit this book. I surely could not accomplish much without the love and support of my wife, children, mother, and family. I would like to thank Dr. Kenneth Mautner for first introducing me to PRP in residency. I would like to thank Drs. Christopher Centeno and John Schultz for pioneering much of this field and serving as great mentors and colleagues. Also, thank you to Dr. Ron Hanson for teaching me many of these techniques as a fellow. Many thanks to all the contributing authors for their time and expertise. Thank you to my staff who helped me acquire so many pictures for the book. Thanks to my co-editors, colleagues, and friends, Dr. Christopher Williams and Dr. Walter Sussman. It has been an honor and privilege to tackle this monumental task with you. Thank you to my patients for humbling and teaching me daily. Additionally, thanks to our publishing team at Elsevier for all the hard work of bringing this to print. Lastly, thank you to all the readers who will see this book as you are the reason for this.

John Pitts, MD

I would like to thank my family, especially my wife and three children, for their patience and understanding over this past year, and my co-editors Dr. Chris Williams and Dr. John Pitts, whose clinical skill and time are reflected in the broad scope of this book. While at Emory, I had the benefit of training with so many talented musculoskeletal and spine physicians, whose focus on individualized patient care, minimally invasive image-guided treatments, and finding new and effective treatments influenced this text and continue to guide my practice. A special thank you to Dr. Ken Mautner. I wouldn’t be where I am today without his mentorship and introduction to this innovative field. I would like to also recognize Drs. Hassan Monfared, Lee Kneer, and John Xerogeanes at Emory and Drs. John Lin and Eric Shaw at the Shepherd Center for their time and guidance. Thank you to all whose work, expertise, and support helped with this textbook, including all the contributing authors, publishing team Elsevier, and all the readers. Finally, a big thank you to my patients and colleagues who continue to teach me daily.

Walter Sussman, DO

1 Introduction to Interventional Orthopedics and Review of the Pathophysiology of Orthopedic Conditions

WALTER I. SUSSMAN, JOHN PITTS, AND CHRIS WILLIAMS

Interventional orthopedics is a developing field that attempts to bridge the gap between traditional non-operative orthopedics (e.g., sports medicine, interventional spine or pain medicine) and surgical interventions. This field expands the traditional approach to orthopedic problems, broadening the number of diagnoses and pathology that can be targeted with minimally invasive injections and procedures. For instance, instead of only evaluating orthopedic pathology as severe enough versus not severe enough for surgery, we offer alternative interventions for patients that have not responded to conservative therapy such as patients with partial tendon or ligament tears, ligament laxity, and nerve entrapment syndromes where surgical options are limited. The use of diagnostic ultrasound to complement the traditional orthopedic history and examination allows the clinician to more accurately diagnose and then target the underlying soft tissue and joint pathology.

Instead of traditional interventions being limited to unguided injections and surgery, interventional orthopedics utilizes interventional musculoskeletal ultrasound and fluoroscopy to guide injections to expand treatment options with the goal of precisely targeting and treating common orthopedic problems. The use of image guidance for procedures has increased over the past decades, largely driven by decreased equipment costs, patient safety initiatives, and higher-resolution imaging.1–3 In many cases, “blind” injections have been supplanted by image guidance, which gives the clinician the ability to directly visualize the target tissues and more accurately target specific pathology.

Therapeutic injections may include corticosteroids, but there is a focus on understanding the appropriate role of alternative injectates, which can be utilized to more accurately address the underlying pathophysiology. With the advent and expansion of regenerative treatments and orthobiologics, there is an increasing emphasis on tissue preservation, restoration of tissue function, and healing rather than solely procedures that target “inflammation” and only provide temporary pain relief, or more invasive surgical procedures carrying increased cost and risk of complications.

The traditional approach to the management of musculoskeletal pathology has largely been driven by locating and treating the primary pain generator. A good example is the treatment of low back pain. Typically, the interventionalist would try and identify a primary pain (i.e., the nerve root, facet joint, sacroiliac joint dysfunction, myofascial pain, or intradiscal pathology) and construct a treatment plan to specifically address the area of the spine most likely responsible for the patient symptoms. Conversely, an interventional orthopedics approach would take an approach of addressing the entire spine as a “functional spinal unit” and consider the interplay of these structures and the biomechanical role of adjacent ligaments, tendons, and muscles. The overall goal extends beyond general pain management and looks to address the underlying etiology of musculoskeletal pathology for long-term improvements in functional outcomes. With this in mind, the treatment plan for low back pain may include treating the lumbar facets, corresponding level epidurals if there is myoneural dysfunction on examination

(e.g., weakness or gluteal enthesopathy at the posterior iliac crest), supraspinous and interspinous ligaments for stability, and possibly the multifidus muscle if there is decreased activation on examination and atrophy on magnetic resonance imaging (MRI).

The convergence of advances in imaging, an evolving understanding of the pathophysiology of both acute and chronic degenerative pathology, and a growing interest in minimally invasive approaches to orthopedic pathology has fueled this field and has expanded the type of injections and procedures performed.1 Some of the procedures discussed in this text did not exist before the widespread adoption of ultrasound. Many of these new procedures have become more common, including nerve hydrodissection, barbotage of calcific tendinosis, and percutaneous needle tenotomy procedures. Others are characterized by using specialized surgical tools or devices to duplicate surgical procedures using a percutaneous approach that will expand and continue to be adopted due to improved safety and morbidity.

The growth of regenerative injections, including but not limited to dextrose, platelet-rich plasma, and autologous stem cells, has also driven the emergence of new techniques and procedures. In some cases, the use of these treatments clinically has outpaced the scientific data. The scientific literature will undoubtedly evolve, and the field of interventional orthopedics will continue to mature and as we explore alternatives to many of the more traditional injectates and many surgical techniques that have limited evidence and efficacy.4,5 Several studies have been published that question whether nonsurgical conservative measures, sham surgeries, or placebo therapy is as effective as management. In some cases, it is unclear if the traditional injections with corticosteroids or surgical interventions are better than non-operative management, placebo, or sham surgery, including the intermediate and long-term benefit of corticosteroids,6–9 arthroscopic meniscectomy, and debridement in patients with arthritis,9–17 or subacromial decompression surgery for rotator cuff impingement.18–21

This introductory chapter focuses on the composition and organization of different tissue types and the current concepts in the pathophysiology of orthopedic conditions and how our understanding of common musculoskeletal conditions has influenced current and future management strategies. Conventional nonoperative therapies have targeted inflammation, but inflammation is important to the healing process. Treatment strategies must be tailored to the underlying tissue involved (nerve, muscle, tendon, ligament, bone, and cartilage) and the underlying pathology.

Tendinopathy

Tendons come in various shapes and sizes and connect muscle to bone. The normal tendon structure is largely composed of collagen and proteoglycans. Type I collagen comprises approximately 65% to 80% of the dry mass of the tendon, with smaller amounts of type II, III, IV, V, IX, and X collagen also present.22 Collagen molecules are

cross-linked polypeptide chains, and their principal role is to resist tension, while proteoglycans are primarily responsible for the viscoelastic behavior of the tendon.23 The tendon is organized in a helical architecture, comparable to man-made ropes.24 This helical organization of the tendon components is present at various levels or organizations, including when collagen fibers are bundled together to form fascicles, and fascicles are bundled to form the tendon itself.

The cellular component of the tendon is made up of tenoblasts and tenocytes arranged in parallel rows among the collagen fibers. Tenoblasts are immature tendon cells and transform into tenocytes as they mature. Tenocytes function to synthesize collagen and other components of the extracellular matrix (ECM). Tenoblasts and tenocytes comprise 90% of the cellular component of the tendon, with the remaining 5% to 10% made up of chondrocytes, synovial cells, and vascular cells.22,25

A thin film of loose connective tissue (endotenon) is present between the fascicles, allowing the fascicles to slide independently against each other. The endotenon is continuous with the connective tissue (epitenon) that surrounds the tendon as a whole (Fig. 1.1). Some tendons, such as the Achilles tendon, have a paratenon that surrounds the tendon but separate from the tendon itself.23 The paratenon is made up of type I and III collagen fibers, and the inner surface is lined by synovial cells. In some cases, the tendon is surrounded by a true synovial sheath. There is often great confusion when describing the tissue that surrounds the tendon.

The tendon inserts on bone in the form of a myo-enthesis or cartilaginous entheses. Myo-enthesis have superior blood supply and are less prone to degenerative pathology. Intrinsic blood supply to the tendon is located at the myotendinous and osteotendinous junction, with extrinsic blood supply coming from the paratenon and synovial sheath. The musculotendinous junctions and entheses are vulnerable sites, and increased age and mechanical loading can decrease vascular supply to these areas. Small afferent nerves throughout the paratenon form plexuses with penetrating branches innervating the tendon.

Areas of the tendon with poor blood supply are at increased risk of injury. While tendon injuries can occur in the mid-tendon (i.e., Achilles), most pathology and pain arise at the enthesis. Poor blood supply predisposes damaged tendons to tissue hypoxia. Tendinopathy is thought to develop from excessive loading and tensile strain. Although load is a major component in the development pathology, the etiology of tendinopathy is likely multifactorial and includes genetics,26 age,27 body composition,28 comorbidities (e.g., dyslipidemias, rheumatoid disease, tumors, infections, heritable connective tissue diseases, endocrinopathies including thyroid disease, metabolic diseases including diabetes), and medication exposure (e.g., statin, fluoroquinolones).29

The interplay between structural change, dysfunction, and pain is still not fully understood. Historically, tendon pain has been described as tendinitis, implying that inflammation was the central pathologic process. At the cellular level in early and chronic tendinopathy, there are

an increased number of leukocytes (primarily macrophages and mast cells).30–32 However, compared to rheumatoid arthritis and other immune-driven pathology, the number of leukocytes is small,29 and there has been widespread recognition that the terminology of tendinitis, tendinosis, and paratenonitis should reflect the histopathologic feature of the tendon.33

Histopathologic studies have shown the progression from normal ECM to reactive response and tendon disrepair, characterized by greater tissue matrix breakdown, collagen separation, neovascularization, and proliferation of abnormal tenocytes. The new model of tendon pathology is of a continuum that has three stages: reactive tendinopathy, tendon disrepair (failed healing), and degenerative tendinopathy.34–36 While these are described as three distinct stages for convenience, the idea of a continuum recognizes that the tendon can move forward or back along this continuum. This model highlights the need to tailor treatments to the specific tendon pathology and that a single intervention is unlikely to be efficacious in every case.

Ligament Injury

Similar to tendon tissue, ligaments are constructed from dense regular connective tissue and can vary in size, form, orientation, and location.37 Skeletal ligaments stabilize the joint and guide the joint through a normal range of motion and provide proprioception to coordinate movements.37,38 The orientation of collagen fibrils tends to be in the direction of applied force, and while tendon collagen fibrils tend to be in parallel, the ligament collagen fibrils are not uniformly oriented as forces are applied in more than one direction.38 Type I collagen makes up 85% of the ligament, depending on the type of ligament, with the rest of the

ligament composed of type III, VI,V, XI, and XIV collagen.37 Collagen bundles within ligaments have a crimped appearance, and with stress, the ligament elongates as collagen fibers uncrimp. This allows the ligament to elongate without sustaining damage, contributing to the viscoelastic property of the ligament.37

In both tendons and ligaments, the major cell type is the fibroblast, or ligamentoblast and ligamentocytes.37 Epiligamentous plexus forms a net-like branching anastomotic pattern on the surface of the ligament with branches that penetrate the ligament and become intraligamentous vessels distributed into longitudinal channels within the ligament.39 The distribution of blood vessels varies among ligaments, and compared to the synovial tissue or bone, ligaments appear to be relatively hypovascular.39

Ligaments are most often injured in traumatic injuries and follow the three phases of healing (inflammation, proliferative, and remodeling).40 Although the ligament may heal, the scar tissue that forms has major differences in collagen types,41 failure of collagen crosslinking,42 altered cell connections,43 small collagen fibril diameter,44 and increased vascularity.45 Even after fully healing, the ligament matrix apparels grossly, histologically, and biomechanically different from normal ligament tissue.46 The remodeled ligament can contain material other than collagen, including blood vessels, adipose cells, and inflammatory cells, resulting in weakness.37,46,47 In studies of injured medial collateral ligaments (MCLs), the ligament typically remains weaker after healing and only regains 40% to 80% of the strength and stiffness compared to normal MCLs.46,48 The viscoelastic property of an injured ligament has a somewhat better recovery, returning to within 10% to 20% of normal.46

Ligaments have a poor regenerative capacity due to the low cell density and lack of blood flow, and after an injury,

Secondar y fiber bundle

Ter tiar y fiber bundle

Tendon

Paratenon

Epitenon

Endotenon

Primar y fiber bundle

Collagen fibril

Collagen fiber

• Fig. 1.1 Hierarchy of a Tendon.