Distal Radius Fractures and Carpal Instabilities E-Book

• Herausgeber: Thieme
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 762

Veröffentlichungsjahr: 2019

Beschreibung

A comprehensive summary of the state of the art in the management of fractures of the distal radius and carpal instability

Hand and wrist fractures account for millions of emergency room visits annually. The extraordinary importance of these structures in activities of daily living necessitates great surgical competence in repairing fractures, so as to preserve the vast range of motion and utility of this functional anatomic unit.

The management theory and techniques for these fractures have seen dramatic changes in the last few decades. This new volume brings together all currently established operative techniques for distal radius fractures, explained in detail and highly illustrated, step by step, with a wealth of brilliant figures and diagrams.

Key Features:

• Comprehensive coverage of all types of injury as well as all the evidence-based therapeutic surgical options
• State-of-the-art management of carpal instability, anterior and dorsal rim fractures, radiocarpal dislocation, malunion, and much more
• Includes coverage of ligamentous injuries
• Contributions by numerous world-renowned surgeons

This book is ideal for all surgeons in training in orthopaedic surgery and in plastic surgery, and of benefit to experienced surgeons as well.

This book includes complimentary access to a digital copy on https://medone.thieme.com.

Leseprobe

Distal Radius Fractures and Carpal Instabilities

FESSH IFSSH 2019 Instructional Book

Editor-in-Chief:Francisco del Piñal, MD, PhDFormer Secretary General and Former President of EWASHand and Microvascular SurgeonMadrid and Santander, Spain

Co-Editors:Max Haerle, MD, PhDProfessorFormer General Secretary of FESSHFormer President of EWASDirector of Hand and Plastic Surgery DepartmentOrthopädische Klinik MarkgröningenMarkgröningen, Germany

Hermann Krimmer, MD, PhDProfessorChief of Hand CenterSt. Elisabeth HospitalRavensburg, Germany

645 illustrations

ThiemeStuttgart • New York • Delhi • Rio de Janeiro

Library of Congress Cataloging-in-Publication Data is available from the publisher.

© 2019. Thieme. All rights reserved.

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ISBN 978-3-13-242379-4

Also available as an e-book:eISBN 978-3-13-242380-0

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Contents

Preface

Contributors

1Anatomy of the Fracture

Simon MacLean, Gregory Bain

1.1 Introduction

1.2 Microanatomy of the Distal Radius: A Feat of Evolutionary Engineering

1.2.1 The Subchondral Bone Plate: the “Leaf Spring” of the Wrist

1.2.2 The Arch Bridge Concept

1.2.3 Multiple Rings Concept of the Wrist

1.3 The Role of the Carpal Ligaments

1.4 Fracture Initiation and Propagation

1.5 Scapholunate Dissociation and Two-Part Fractures of the Distal Radius

1.6 Volar Marginal Rim Fractures

1.7 A Biomechanical Model for Distal Radius Fracture

1.8 Summary

References

2Radiology of the Fractured Radius

Mark Ross, Patrick Groarke

2.1 Introduction

2.2 Plain Radiographs

2.2.1 Injury (Prereduction) Radiographs

2.2.2 Postreduction Radiographs

2.2.3 Parameters Can Change with Time

2.2.4 Radiograph of the Opposite Side

2.2.5 Posteroanterior View

2.2.6 Lateral View

2.3 Plain Radiographic Parameters

2.3.1 Posteroanterior View

2.3.2 Lateral View

2.4 Effect of Wrist Position on Carpal Indices

2.5 Reproducibility of Indices

2.6 Effect of Lateral Inclination on Volar Tilt

2.7 Intra-articular Components

2.8 Are the Parameters Reproducible?

2.9 Determination of Stability of Fracture Pattern and Adequacy of Reduction

2.9.1 Extra-articular Stability

2.9.2 Intra-articular Reduction

2.10 Other Signs on Radiographs

2.11 Frequency of Radiographic Assessment

2.12 Classification of Distal Radius Fractures

2.13 Computed Tomography

2.13.1 Sagittal Computed Tomography

2.13.2 Coronal Computed Tomography

2.13.3 Axial Computed Tomography

2.13.4 Computed Tomography and DRUJ Stability

2.13.5 Three-Dimensional Reconstructions

2.14 Magnetic Resonance Imaging and Distal Radius Fractures

2.15 Summary

2.15.1 Plain Radiographs

2.15.2 Computed Tomography Scans

2.15.3 Magnetic Resonance Imaging Scans

References

3Patient–Accident–Fracture Classification of Acute Distal Radius Fractures in Adults

Guillaume Herzberg, Thais Galissard, Marion Burnier

3.1 Introduction

3.2 Material and Methods

3.2.1 Patient

3.2.2 Accident

3.2.3 Fracture

3.3 Results and Discussion

3.3.1 Patients 1–1 (Dependent, Minimal Functional Needs) with AO Type “A” or “C” Fractures

3.3.2 Patients 2–2 (Independent Patients with Comorbidities, Intermediate Functional Needs) with AO Type “A” Extra-articular Fractures

3.3.3 Patients 2–2 (Independent Patients with Comorbidities, Intermediate Functional Needs) with AO Type “C” Intra-articular Fractures

3.3.4 Patients 3–3 (Patient with Normal General Health Status and Maximal Functional Needs) with AO Type “A” Extra-articular Fractures

3.3.5 Patients 3–3 (Patient with Normal General Health Status and Maximal Functional Needs) with AO Type “C” Intra-articular Fractures

3.3.6 Patients 3–3 (Patient with Normal General Health Status and Maximal Functional Needs) with AO Type “B” Partial Articular Fractures

3.4 Conclusion

References

4Distal Radius Fracture: The Evidence

Tracy Webber, Tamara D. Rozental

4.1 Introduction

4.2 Methods

4.3 Nonoperative Fracture Treatment

4.4 Surgery versus Immobilization for Displaced Distal Radius Fracture

4.5 The Management of Elderly Patients

4.6 Operative Treatment for Displaced Distal Radius Fracture: Method of Fixation

4.6.1 Bridging versus Nonbridging External Fixation

4.6.2 Closed Reduction Percutaneous Pinning versus Open Reduction Internal Fixation

4.6.3 Closed Reduction Percutaneous Pinning versus External Fixation

4.6.4 Open Reduction Internal Fixation versus External Fixation

4.6.5 Implant Type

4.6.6 Management of the Pronator Quadratus

4.7 Postoperative Rehabilitation

4.8 Management of Complications

4.9 Treatment for Osteoporosis

4.10 Conclusion

References

5Orthopaedic Treatment: When?

David Warwick, Oliver Townsend

5.1When the Evidence and Benefits of Nonoperative Treatment Have Been Considered

5.1.1 Why Surgery Is Not Usually Needed

5.1.2 Nonoperative Treatment Is Usually Effective

5.1.3 Surgery Carries Risk

5.1.4 Risks of Nonoperative Intervention

5.2When the Literature Recommendations Have Been Considered

5.2.1 Drawbacks of the Literature

5.2.2 Authors’ Recommendations

5.2.3 Consensus Review

5.3When Age Has Been Considered

5.3.1 Older Age

5.3.2 Younger Age

5.4When There Is a Predictable Risk of Poor Outcome

5.4.1 Exclusion Bias

5.4.2 Distal Radioulnar Joint Incongruity

5.4.3 Adaptive Midcarpal Malalignment

5.4.4 Positive Ulnar Variance

5.4.5 Fracture Dislocation

5.5When There Is a Predictable Risk of Instability

5.5.1 Instability

5.5.2 Prediction of Instability

5.6When There Is a Predictable Risk of Symptomatic Arthritis

5.6.1 Does Arthritis Really Matter in the Hand and Wrist?

5.6.2 How Often Does a Hand Surgeon Actually See Arthritis after a Distal Radius Fracture?

5.6.3 Literature Evidence

5.7When the Appropriate Method Is Available

5.8When the Patient Understands the Options and the Risks

5.8.1 The Patient’s Rights

5.8.2 Honest Consent

5.8.3 Personalized Treatment

5.9When the Patient Prefers to Have Urgent Surgery that May Not Be Needed rather than Wait for a Corrective Osteotomy

5.9.1 Natural History of Recovery after Distal Radius Fracture

5.9.2 Managing Uncertainty

5.9.3 Rescuing a Wrong Decision with Corrective Osteotomy

5.10When the Patient Wants Early Return of Function

5.11When Cost-Benefit Analysis Supports Surgery

5.12 Conclusion

References

6Is There a Role for External Fixation with or without Kirschner Wires?

Frédéric Schuind

6.1 Introduction

6.2 Indications and Contraindications

6.3 Surgical Techniques

6.4 Prevention of Redisplacement

6.5 Prevention of Other Complications of External Fixation

6.6 Results

6.7 Conclusion

References

7Volar Locking Plates: Basic Concepts

Hermann Krimmer

7.1 Introduction

7.2 Locking Mechanisms

7.3 Indications

7.3.1 Plate Design and Plate Position

7.3.2 Fracture-Specific Plate Selection

7.4 Surgical Technique

7.5 Pitfalls

7.5.1 Tendon Ruptures

7.5.2 Secondary Subsidence

References

8Intramedullary Devices

Stephanie Malliaris, Scott Wolfe

8.1 Introduction

8.2 Indications

8.3 Intramedullary Nail: Surgical Technique

8.4 Intramedullary Nail: Outcomes

8.5 T-Pin: Surgical Technique

8.6 T-Pin: Outcomes

8.7 Distal Radius System Intramedullary Cage: Surgical Technique

8.8 Distal Radius System Intramedullary Cage: Outcomes

8.9 Pitfalls and Contraindications

8.10 Conclusion

References

9Mini Approaches

Gustavo Mantovani Ruggiero

9.1 Introduction

9.2 Volar Minimally Invasive Plate Osteosynthesis History

9.3 Indications

9.4 Surgical Technique

9.4.1 Single Longitudinal Incision

9.4.2 Transverse Incision

9.5 Evolution of Distal Radius Fractures Minimally Invasive Plate Osteosynthesis

9.5.1 Special Plates

9.6 Results, Clinical Examples, and Unusual Minimally Invasive Plate Osteosynthesis Cases

9.7 Pitfalls and Contraindications

9.8 Conclusions

References

10Spanning Plates

Mitchell G. Eichhorn, Scott G. Edwards

10.1 Introduction

10.2 Indications

10.3 Surgical Technique

10.3.1 Third Metacarpal Technique

10.3.2 Second Metacarpal Technique

10.4 Results

10.5 Pitfalls and Contraindications

10.6 Conclusion

References

11Arthroscopic Management

Yukio Abe

11.1 Introduction

11.2 Indications

11.3 Surgical Technique

11.3.1 Preoperative Planning

11.3.2 Preparation and Patient Positioning

11.3.3 Surgical Approach

11.3.4 Postoperative Care

11.4 Results

11.4.1 The Advantages of Wrist Arthroscopy

11.4.2 Outcomes

11.5 Complications

11.6 Conclusion

References

12Anterior Rim Fractures

Jorge L. Orbay, Gabriel Pertierra

12.1 Introduction

12.1.1 Background

12.1.2 Classification

12.1.3 Anatomy and Biomechanics

12.2 Indications

12.3 Surgical Technique

12.3.1 Salvage of a Collapsed VMF

12.4 Results

12.5 Pitfalls and Contraindications

12.6 Conclusion

References

13Dorsal Rim Distal Radius Fractures with Radiocarpal Fracture-Dislocation

Rohit Garg, Jesse Jupiter

13.1 Introduction

13.2 Indications

13.3 Surgical Technique

13.3.1 Case 1

13.3.2 Case 2

13.3.3 Case 3

13.3.4 Case 4

13.4 Results

13.5 Conclusion

References

14Multiplanar Fixation in Severe Articular Fractures

Peter C. Rhee, Alexander Y. Shin

14.1 Introduction

14.1.1 Understanding the Fracture Characteristics

14.1.2 Limitations of Volar Locking Plate Fixation

14.1.3 Rationale for Fragment-Specific Fixation

14.2 Indications

14.3 Surgical Technique (Authors’ Preferred)

14.3.1 Preoperative Planning

14.3.2 Sequence of Reconstruction

14.3.3 Management of the Volar Rim Fragment

14.3.4 Management of the Dorsal Ulnar Corner Fragment

14.3.5 Management of Free Intra-articular Fragments

14.3.6 Management of the Dorsal Wall Fragment

14.3.7 Management of the Radial Column Fragment

14.3.8 Finishing Steps

14.4 Results for Multiplanar Plate Fixation with Fragment-Specific Implants

14.4.1 Functional Outcomes

14.4.2 Radiographic Outcomes

14.4.3 Complications

14.4.4 Comparison of Fragment-Specific to Volar Locking Plate Fixation

14.5 Pitfalls and Contraindications

14.6 Conclusion

References

15Management of Wrist Open Fractures and Bone Defects

Rames Mattar Junior, Emygdio Jose Leomil de Paula, Luciano Ruiz Torres, Tiago Guedes da Motta Mattar, Gustavo Bersani Silva

15.1 Introduction

15.2 Indications

15.3 Surgical Technique

15.3.1 Fracture Management

15.3.2 Soft Tissue Repair

15.3.3 Nerve Injuries

15.3.4 Tendons

15.3.5 Amputations and Devascularizations

15.4 Results

15.5 Pitfalls

15.6 Conclusion

References

16Radiocarpal Dislocation

Mark Henry

16.1 Introduction

16.2 Indications

16.3 Surgical Technique

16.4 Results

16.5 Pitfalls and Contraindications

References

17Common Errors of Volar Plate Fixation

Robert J. Medoff, James M. Saucedo

17.1 Background

17.2 Errors of Surgical Exposure

17.3 Hardware-Related Errors

17.4 Tendon Complications

17.4.1 Flexor Tendon Rupture and Irritation

17.4.2 Extensor Tendon Injury and Rupture

17.5 Inadequate Reduction and Fixation

17.6 Conclusion

References

18Distal Ulna Fractures

Christopher Klifto, David Ruch

18.1 Introduction

18.2 Indications

18.2.1 Ulnar Styloid Fractures/Nonunions

18.3 Surgical Technique

18.3.1 Approach

18.3.2 Ulnar Styloid Fractures Technique

18.3.3 Ulnar Head Fractures

18.3.4 Comminuted Intra-articular Distal Ulnar Fractures

18.4 Results

18.5 Pitfalls

18.6 Conclusion

References

19Distal Radioulnar Joint Instability Associated with Distal Radius Fractures

Shohei Omokawa, Takamasa Shimizu, Kenji Kawamura, Tadanobu Onishi

19.1 Introduction

19.2 Pathomechanics of DRUJ Instability

19.2.1 Metaphyseal Fracture Displacement

19.2.2 Disruptions Accompanying TFCC (Radioulnar Ligament) Tears

19.2.3 Ulnar Styloid Fractures

19.2.4 Intra-articular Displacement of the Sigmoid Notch

19.3 Case Presentation

19.4 Diagnosis of Accompanying TFCC Tears and DRUJ Instability

19.4.1 Preoperative Assessment

19.4.2 Intraoperative Assessment

19.4.3 DRUJ Arthrography

19.5 Treatment for TFCC Tears and DRUJ Instability

19.5.1 Authors’ Preferred Method

19.6 Summary

References

20Distal Radius Fracture in the Elderly

Rohit Arora, Markus Gabl

20.1 Introduction

20.2 Indications

20.3 Treatment Options

20.3.1 Closed Reduction and Cast Immobilization

20.3.2 Closed Reduction and Percutaneous Pinning

20.3.3 External Fixation

20.3.4 Volar Locking Plate Fixation

20.3.5 Distal Radius Arthroplasty

20.3.6 Initial Shortening and Palmar Plate Fixation with Primary Sauve-Kapandji Procedure

20.4 Complications

20.5 Conclusion

20.6 Our Algorithm of Treatment

20.7 Initial Treatment

References

21Extra-articular Malunion

Karl-Josef Prommersberger

21.1 Introduction

21.1.1 Biomechanics of Distal Radial Malunion

21.1.2 Treatment Options

21.2 Indications and Contraindications

21.3 Surgical Technique

21.3.1 Timing for Radial Correction Osteotomy in an Extra-articular Malunion

21.3.2 Preoperative Work-up

21.3.3 Technique

21.4 Results

21.4.1 Own Results

21.5 Pitfalls

21.6 Conclusion

References

22Arthroscopic-Guided Osteotomy for Intra-articular Malunion

Francisco del Piñal

22.1 Introduction

22.2 Indications and Contraindications

22.3 Surgical Technique

References

23Newer Technologies on Managing Distal Radius Fractures

Ladislav Nagy

23.1 Introduction

23.2 Indications

23.3 Surgical Technique

23.3.1 Extra-articular Malunion

23.3.2 Intra-articular Malunion

23.3.3 Intra-articular Fractures of the Distal Radius

23.4 Results

23.5 Pitfalls and Contraindications

23.6 Conclusion

References

24Distal Radius in Children and Growth Disturbances

Alexandria L. Case, Joshua M. Abzug

24.1 Distal Radius Fractures in Children: Introduction

24.1.1 Extraphyseal Fractures

24.1.2 Physeal Fractures

24.1.3 Indications and Contraindications

24.1.4 Surgical Technique

24.1.5 Results

24.1.6 Pitfalls

24.2 Growth Disturbances Following Distal Radius Fractures: Introduction

24.2.1 Indications and Contraindications

24.2.2 Surgical Techniques

24.2.3 Results

24.2.4 Pitfalls

24.3 Conclusion

References

25Open Surgery for Chronic Scapholunate Injury

Dirck Ananos, Marc Garcia-Elias

25.1 Introduction

25.1.1 Terminology

25.1.2 Ligaments Involved in Scapholunate Instability

25.2 Indications

25.3 Surgical Technique

25.4 Results, Pearls, and Tips

25.4.1 Case Example

25.4.2 Pitfalls and Contraindications

25.5 Conclusion

References

26Arthroscopic Scapholunate Repair

Max Haerle, Christophe Mathoulin

26.1 Introduction

26.2 Indications

26.3 Surgical Technique

26.4 Results

26.5 Pitfalls and Contraindications

26.6 Conclusion

References

27Treatment of Lunotriquetral Injuries

Benjamin F. Plucknette, Haroon M. Hussain, Lee Osterman

27.1 Anatomy

27.2 Diagnosis and Classification

27.3 Treatment of Acute LT Injuries

27.3.1 Nonoperative Management

27.3.2 Operative Management

27.4 Treatment of Chronic Lunotriquetral Injuries

References

28Arthroscopic Management of Perilunate Dislocation and Fracture Dislocation

Jae Woo Shim, Jong-Pil Kim, Min Jong Park

28.1 Introduction

28.2 Indications

28.3 Surgical Technique

28.4 Results

28.4.1 Clinical Results

28.4.2 Radiological Results

28.5 Complications

28.6 Pitfalls and Contraindications

28.7 Conclusion

References

29Radiocarpal Pain and Stiffness

Christoph Pezzei, Stefan Quadlbauer

29.1 Introduction

29.2 Surgical Techniques

29.2.1 Denervation of the Wrist

29.2.2 Wrist Arthrolysis

29.2.3 Partial Wrist Arthrodesis

29.2.4 Wrist Arthroplasty

29.2.5 Total Wrist Arthrodesis

29.3 Conclusion

References

30Ulnar Pain and Pronosupination Losses

Riccardo Luchetti, Andrea Atzei

30.1 Introduction

30.2 Indication

30.3 Diagnostic Imaging

30.3.1 Radiography

30.3.2 CT Scan

30.3.3 Magnetic Resonance Imaging

30.3.4 Arthrography, ArthroCT, and ArthroMRI

30.4 Surgical Options

30.4.1 Open Arthrolysis

30.4.2 Arthroscopic Arthrolysis

30.5 Results

30.6 Contraindications

30.7 Conclusion

30.8 Types of Painful DRUJ Rigidity

30.8.1 Dislocation or Dorsal Subluxation and Positive Ulna Variation Secondary to Distal Radius Malunion

30.8.2 Loss of Pronosupination due to Screws Interposed into the DRUJ

30.8.3 Interposition of the Extensor Digiti Minimi

30.8.4 Ulna Malunion

References

31Chronic Distal Radioulnar Joint Instability

Michael C. K. Mak, Pak-Cheong Ho

31.1 Introduction

31.1.1 Distal Radioulnar Joint Anatomy and Its Stabilizers

31.2 Indications

31.2.1 Correction of Skeletal Deformity

31.2.2 Triangular Fibrocartilage Complex Reconstruction

31.3 Surgical Technique

31.3.1 Setup and Instruments

31.4 Rehabilitation

31.5 Outcomes and Complications

31.6 Conclusion

References

Index

Preface

It is a great privilege that the International Federation of Societies for Surgery of the Hand (IFSSH) and the Federation of European Societies for Surgery of the Hand (FESSH) have considered me as editor-in-chief of this book on the burning issue of distal radius fractures and ligamentous injuries.

Management of distal radius fractures and wrist ligamentous injuries has seen dramatic changes in the last few decades. For those of us who have lived this on the front line, it has been a very exciting experience. Beginning from casts, external fixateurs, intramedullary devices, volar or dorsal plates, and finally to arthroscopy, all have contributed to making it possible to provide our patients with outstanding results. One thing we have learned is that no one method can be used for all injuries, as the personality of each fracture or ligamentous injury demand a different approach. For this reason, every available treatment has its own space in our armamentarium.

Fully conscious of this, we have compiled here an up-to-date selection of the techniques available to tackle all injury types. The topics have been carefully selected to cover the subjects of greatest interest or higher impact. In this endeavor, we have had the fortune to count on world-renowned surgeons, who have championed the changes we are now using in our everyday practice. Some chapters provide new answers or refinements to recurrent problems.

This book will hopefully improve the care of our patients and, furthermore, inspire the creativity of future generations of surgeons.

Finally, I would like to thank my co-editors and all the authors who have devoted their precious time to sharing their knowledge with us.

Paco PiñalMadrid, 2019

Contributors

Yukio Abe, MD, PhD

Director

Department of Orthopaedic Surgery

Saiseikai Shimonoseki General Hospital

Shimonoseki, Japan

Joshua M. Abzug, MD

Associate Professor

Departments of Orthopedics and Pediatrics

University of Maryland School of Medicine

Director of Pediatric Orthopedics

University of Maryland Medical Center

Deputy Surgeon-in-Chief

University of Maryland Children‘s Hospital

Baltimore, Maryland, USA

Dirck Ananos, MD

Fellow

Kaplan Hand Institute

Barcelona, Spain

Rohit Arora, MD

Department of Trauma Surgery

Medical University Innsbruck

Innsbruck, Austria

Andrea Atzei, MD

Fenice Hand Surgery and Rehabilitation Team

Treviso, Italy

Gregory Bain, MD

APWA President

Professor of Upper Limb and Research

Department of Orthopaedic Surgery

Flinders University

Adelaide, South Australia, Australia

Marion Burnier, MD

Wrist Surgery Unit

Department of Orthopaedics

Claude-Bernard Lyon 1 University

Herriot Hospital

Lyon, France

Alexandria L. Case, MD

Clinical Research Coordinator

Department of Orthopedics

University of Maryland School of Medicine

Baltimore, Maryland, USA

Scott G. Edwards, MD

Chief of Hand and Upper Extremity Surgery

Banner University Medical Center

The CORE Institute Specialty Hospital

Phoenix, Arizona, USA

Mitchell G. Eichhorn, MD

Hand Surgery Fellow

University of Arizona Banner Hand Surgery Fellowship

Phoenix, Arizona, USA

Markus Gabl, MD

Department of Trauma Surgery

Medical University Innsbruck

Innsbruck, Austria

Thais Galissard, MD

Wrist Surgery Unit

Department of Orthopaedics

Claude-Bernard Lyon 1 University

Herriot Hospital

Lyon, France

Marc Garcia-Elias, MD, PhD

Consultant and Co-Founder

Kaplan Hand Institute

Barcelona, Spain

Honorary Consultant

Pulvertaft Hand Center

Derby, UK

Rohit Garg, MBBS

Hand and Upper Extremity Orthopaedic Surgeon

Massachusetts General Hospital

Boston, Massachusetts, USA

Patrick Groarke, MD

Brisbane Hand and Upper Limb Research Institute

Brisbane Private Hospital

Brisbane, Queensland, Australia

Orthopaedic Department

Princess Alexandra Hospital

Woolloongabba, Queensland, Australia

Max Haerle, MD, PhD

Professor

Former General Secretary of FESSH

Former President of EWAS

Director of Hand and Plastic Surgery Department

Orthopädische Klinik Markgröningen

Markgröningen, Germany

Mark Henry, MD

Practicing Hand Surgeon

Hand and Wrist Center of Houston

Houston, Texas, USA

Guillaume Herzberg, MD, PhD

Professor of Orthopaedic Surgery

Lyon Claude Bernard University

Herriot Hospital

Lyon, France

Pak-Cheong Ho, MD, MBBS, FRCS, FHKCOS, FHKAM(Ortho)

EWAS Former President

APWA Founder and Former President

Department of Orthopaedics and Traumatology

Prince of Wales Hospital

Chinese University of Hong Kong

Hong Kong, SAR China

Haroon M. Hussain, MD

Greater Washington Orthopaedic Group PA

Rockville, Maryland, USA

Rames Mattar Junior, MD

Associate Professor

Department of Orthopedic

Hand and Microsurgery Unit

University Of São Paulo

São Paulo, Brazil

Jesse Jupiter, MD

Hansjorg Wyss AO Professor

Department of Orthopedic Surgery

Massachusetts General Hospital

Harvard Medical School

Boston, Massachusetts, USA

Kenji Kawamura, MD, PhD

Tamai Susumu Memorial Hand and Extremity Trauma Center

Nara Medical University

Kashihara, Japan

Jong-Pil Kim, MD, PhD

Professor

Department of Orthopedic Surgery

Dankook University College of Medicine

Cheonan, South Korea

Christopher Klifto, MD

Assistant Professor

Department of Orthopaedic Surgery

Hand Division

Duke University Medical Center

Durham, North Carolina, USA

Hermann Krimmer, MD, PhD

Professor

Chief of Hand Center

St. Elisabeth Hospital

Ravensburg, Germany

Riccardo Luchetti, MD

Rimini Hand Surgery and Rehabilitation Center

Rimini, Italy

Simon MacLean, MBChB, FRCS(Tr&Orth), PGDipCE

Consultant Orthopaedic and Upper Limb Surgeon

Tauranga Hospital, BOPDHB

Tauranga, New Zealand

Michael C. K. Mak, MD

Division of Hand and Microsurgery

Department of Orthopaedics and Traumatology

Prince of Wales Hospital

Chinese University of Hong Kong

Hong Kong, SAR China

Stephanie Malliaris, MD

Assistant Professor

Plastic and Reconstructive Surgery

University of Colorado School of Medicine

Attending Surgeon

Denver Health Medical Center

Denver, Colorado, USA

Christophe Mathoulin, MD, FMH

Vice-President

Institut de la Main

Founder and Honorary Chairman

European (International) Wrist Arthroscopy Society (EWAS - IWAS)

Founder and Chairman

International Wrist Center–Wrist Clinic

Clinique Bizet

Paris, France

Tiago Guedes da Motta Mattar, MD

Department of Orthopedic

Hand and Microsurgery Unit

University of São Paulo

São Paulo, Brazil

Robert J. Medoff, MD

Assistant Professor

Department of Surgery

University of Hawaii

Honolulu, Hawaii, USA

Ladislav Nagy, MD

Professor

Hand Surgery Division

University Clinic Balgrist

Zürich, Switzerland

Shohei Omokawa, MD, PhD

Department of Hand Surgery

Nara Medical University

Kashihara, Japan

Tadanobu Onishi, MD

Department of Orthopedic Surgery

Nara Medical University

Kashihara, Japan

Jorge L. Orbay, MD

Hand & Upper Extremity Surgeon

The Miami Hand & Upper Extremity Institute

Miami, Florida, USA

Lee Osterman, MD

Professor, Hand and Orthopedic Surgery

Thomas Jefferson University

President

Philadelphia Hand to Shoulder Center

Philadelphia, Pennsylvania, USA

Min Jong Park, MD

Department of Orthopaedic Surgery

Samsung Medical Center

Sungkyunkwan University School of Medicine

Seoul, South Korea

Emygdio Jose Leomil de Paula, MD, PhD

Department of Orthopedic

Hand and Microsurgery Unit

University Of São Paulo

São Paulo, Brazil

Gabriel Pertierra, BA

The Miami Hand & Upper Extremity Institute

Miami, Florida, USA

Christoph Pezzei, MD

Department of Traumatology

AUVA Trauma Hospital Lorenz Böhler–European Hand Trauma Center

Vienna, Austria

Francisco del Piñal, MD, PhD

Former Secretary General and Former President of EWAS

Hand and Microvascular Surgeon

Madrid and Santander, Spain

Benjamin F. Plucknette, DO, DPT

Orthopaedic, Hand, and Microvascular Surgeon

Department of Orthopaedic Surgery

San Antonio Military Medical Center

JBSA-Fort Sam Houston, Texas, USA

Karl-Josef Prommersberger, MD

Professor

Clinic for Hand Surgery

Rhön Klinikum AG

Salzburger Leite

Bad Neustadt an der Saale, Germany

Stefan Quadlbauer, MD

AUVA Trauma Hospital Lorenz Böhler–European Hand Trauma Center

Ludwig Boltzmann Institute for Experimental and Clinical Traumatology

AUVA Research Center

Austrian Cluster for Tissue Regeneration

Vienna, Austria

Peter C. Rhee, DO, MS

Orthopedic Surgery

Mayo Clinic

Rochester, Minnesota, USA

Mark Ross, MD

Brisbane Hand and Upper Limb Research Institute

Brisbane Private Hospital

Brisbane, Queensland, Australia

Orthopaedic Department

Princess Alexandra Hospital

Woolloongabba, Queensland, Australia

School of Medicine

The University of Queensland

St Lucia, Queensland, Australia

Tamara D. Rozental, MD

Chief, Hand and Upper Extremity Surgery

Associate Professor

Department of Orthopaedic Surgery

Beth Israel Deaconess Medical Center

Harvard Medical School

Boston, Massachusetts, USA

David Ruch, MD

Professor and Chief of Division of Hand and Microvascular Surgery

Adjunct Professor of Plastic and Reconstructive Surgery

Duke University Medical Center

Durham, North Carolina, USA

Gustavo Mantovani Ruggiero, MD

São Paulo Hand Center

Hospital Beneficência Portuguesa de São Paulo

São Paulo, Brazil

Hand Surgery Department

Plastic Surgery School

Ospedale San Giuseppe

Università Degli Studi Di Milano

Milan, Italy

James M. Saucedo, MD

The Hand Center of San Antonio

Adjunct Assistant Professor

Department of Orthopaedics

University of Texas Health San Antonio

San Antonio, Texas, USA

Frédéric Schuind, MD, PhD

Full Professor

Université libre de Bruxelles

Head, Department of Orthopaedics and Traumatology

Erasme University Hospital

Brussels, Belgium

Jae Woo Shim, MD

Department of Orthopaedic Surgery

Samsung Medical Center

Sungkyunkwan University School of Medicine

Seoul, South Korea

Takamasa Shimizu, MD, PhD

Department of Orthopedic Surgery

Nara Medical University

Kashihara, Japan

Alexander Y. Shin, MD

Orthopedic Surgery

Mayo Clinic

Rochester, Minnesota, USA

Gustavo Bersani Silva, MD

Department of Orthopedic

Hand and Microsurgery Unit

University Of São Paulo

São Paulo, Brazil

Luciano Ruiz Torres, MD

Department of Orthopedic

Hand and Microsurgery Unit

University of São Paulo

São Paulo, Brazil

Oliver Townsend, BSc, MBBS, MRCS

Core Surgical Fellow

Southampton General Hospital

University Hospital Southampton

Southampton, UK

David Warwick, MD, FRCSOrth, Eur Dip Hand Surg

Professor and Consultant Hand Surgeon

University Hospital Southampton

Southampton, UK

Tracy Webber, MD, BIDMC

Harvard Orthopaedic Hand Fellowship

Department of Orthopaedic Surgery

Beth Israel Deaconess Medical Center

Harvard Medical School

Boston, Massachusetts, USA

Scott Wolfe, MD

Professor

Department of Orthopaedic Surgery

Hospital for Special Surgery

Weill Medical College of Cornell University

New York, New York, USA

1 Anatomy of the Fracture

Simon MacLean, Gregory Bain

Abstract

This chapter discusses the importance of the anatomy of distal radius in relation to fracture. First, we describe the microanatomy of the distal radius. Its microanatomy resembles that seen in everyday engineering structures; the subchondral bone plate and arrangement of trabeculae enabling the wrist to handle high multidirectional loads. Stability of the wrist is achieved by multiple ligamentous rings that confer stability within and between the rows and columns of the wrist. Ligamentous insertions play an important role in fracture morphology, both initiation and propagation of the fracture lines.

Hand position at impact determines the position of the carpus on the distal radius. When a line of differential load occurs in the scapholunate interval, scapholunate ligament injury (SLI) may result. SLI is associated with specific fracture types. “Unmasking” with scapholunate diastasis occurs when there is compromise to the secondary stabilizers.

The volar marginal rim fracture represents an important subset of fractures. These are associated with a higher rate of carpal ligamentous injury and fixation failure. Distal radius plate design has evolved to attempt to capture this fragment.

Lastly, we present a biomechanical model for distal radius fracture.

Keywords: distal radius fracture, microstructure, scapholunate injury, volar rim fracture, radiocarpal ligaments

1.1 Introduction

Distal radius fractures (DRFs) are one of the most commonly treated injuries in orthopaedic practice. A bimodal distribution exists; in younger patients, caused by high-energy and in older patients, caused by low-energy falls. Osteoporotic DRFs reflect a change in the microarchitecture of the distal radius with aging and are a predictor for subsequent fracture of long bones. Classification systems have attempted to provide clarity to the morphology and treatment of these injuries.

With an improved understanding of the anatomy of distal radius, we are better equipped to treat the patient, respecting not just the fracture components but also the contribution of the surrounding ligaments, carpal bones, and other associated injuries. This chapter will explore the importance of each component and its interaction in the mechanism of fracture. First, we will study the microanatomy of the distal radius; and then we will focus on fracture initiation and the role of the carpus; and third, the role of the carpal ligaments and fracture propagation. We will look at the specific anatomy of the volar rim fracture. We will propose a biomechanical model for DRF.

1.2 Microanatomy of the Distal Radius: A Feat of Evolutionary Engineering

Singh reported the trabecular structure of the proximal femur and changed our approach to the understanding and management of these injuries.1 The microstructure of the distal radius assists in understanding its behavior under load. We performed an analysis of the architecture of cadaveric distal radii on micro-computed tomography (CT)2,3 and found it resembled many of the engineering concepts in everyday man-made structures. Interestingly, an engineer once advised us that he knew when he had the design correct and when it resembled the structures identified in nature.

1.2.1 The Subchondral Bone Plate: The “Leaf Spring” of the Wrist

The subchondral bone plate is a 2-mm-thick multilaminar plate that absorbs impact and transmits the load to the radial metaphysis. The superficial “primary” bone plate bridges the entire articular margin. Multiple deeper layers resemble a leaf spring used in the suspension of heavy motor vehicles.

Between these laminae, and connecting them, lie intralaminar struts. These are initially perpendicular to the joint line, but more proximally align with the radial shaft. Voids between the struts and laminae absorb impact and enable vessels to perforate. The struts between the laminae are mini “I-beams,” which make the structure strong but still enable it to bend. Engineers refer to this multilayered lamina construct as a “honeycomb sandwich panel.”

With physiological wrist extension, the volar capsule becomes taut, and the scaphoid and lunate load the distal radius subchondral bone plate.

The multilayered subchondral bone plate resists buckling and transmits the load to the intermediate trabeculae and then the metaphyseal arches (▶Fig. 1.1).

On a magnified view, areas can be seen where these trabeculae coalesce to form a rod and extend as longitudinal ridges down the diaphysis (▶Fig. 1.2). These align in the direction of load through the cortical bone and reinforce the radius, similar to the longerons in a plane’s fuselage (▶Fig. 1.3), and prevent torsional failure and buckling.

The load bearing area of the lunate is very volar. The sagittal images demonstrate the thick volar trabecular columns spanning to the volar cortex of the metaphyseal radius (▶Fig. 1.4). This explains the devastating effect of Barton volar lip fracture, as the carpus will simply dislocate volarly.

Fig. 1.1 Anatomy of the subchondral bone plate of the distal radius.(Copyright © Gregory Bain, MD)

Fig. 1.2 The radial styloid cortex is quite thin but is reinforced by bracing trabeculae. The trabeculae are thin sheets of bone, which are designed to transmit load. There the sheets meet and coalesce into rods, which then become the ridges on the endosteal cortex.(Copyright © Gregory Bain, MD)

Further dorsal on the lunate facet, trabeculae course dorsally forming a curve in the shape of a gothic arch, with an underlying intramedullary “vault.” From medial to lateral through the distal radius, these gothic arches are in series—connected by interarch struts. In normal bone under normal loads, the parabolic shape of the arch transfers loads in a longitudinal and lateral direction, to the base of the arch without creating tension (▶Fig. 1.4).

At the base of each arch, the trabeculae merge with the cortex, which then becomes thickened—therefore buttressing the arch. In contrast, at the articular margin, the cortex is thin. It acts to suspend the subchondral bone plate and serves as a site for ligament attachment, rather than to bear the load.

1.2.2 The Arch Bridge Concept

The microstructure of the distal radius resembles an arch bridge with the following equivalent: deck—SBP, intermediate struts—intermediate trabeculae, arches—arches, and bridge foundation—cortex. The deck is a tightly held lattice with multiple “I-beams” in a multilayer sandwich panel construct. This resists buckling, absorbs impact, and takes the entire load (▶Fig. 1.5).

The arches and intermediate struts are a semiflexible construct, which distributes compressive forces from the deck to the base (diaphysis).4 The orientation of the microstructure ensures that forces are distributed in compression rather than tension (where the bone is weakest).

1.2.3 Multiple Rings Concept of the Wrist

Force transfer from the hand to the radius at the time of DRF involves the transmission of force through the three columns of the wrist. The three columns are bound by a series of ligamentous rings. These ligamentous rings provide stability within and between the proximal and distal rows of the wrist (▶Fig. 1.6).

Within Rows

The distal radioulnar joint is bound by a fibroligamentous ring. Disruption of this at the time of DRF can lead to dislocation of this joint and distal radioulnar instability, if not addressed at the time of surgery.

Within the proximal carpal row, interosseous ligaments on the volar and dorsal aspects of the scapholunate and lunotriquetral joints form a ring. Transmission of force from the central column to the scaphoid, lunate, or both can lead to a disruption of these ligaments and a “greater arc” injury or an impaction fracture of the distal radius.

Fig. 1.3 Longitudinal ridges in the diaphysis of the distal radius resembling a plane’s fuselage.(Copyright © Gregory Bain, MD)

Fig. 1.4 The sagittal microanatomy of the distal radius resembling a gothic arch.(Copyright © Gregory Bain, MD)

The distal carpal row is tightly bound by interosseous ligaments, allowing for minimal motion within the row. Disruption of this ring rarely occurs at the time of DRF but is seen with high-energy axial fracture-dislocations of the carpus.

Between Rows

A series of ligaments connect the rows of the wrist. Kuhlmann ring refers to the volar radiotriquetral ligament and the dorsal radiocarpal ligament (DRC) complexes.5 Disruption of this ring in complex high-energy DRFs can lead to ulnar translocation of the carpus. The DRC also acts as a secondary stabilizer to the scapholunate joint.

The scaphotrapeziotrapezoid (STT) ligament stabilizes the scaphoid to the distal carpal row. As a secondary stabilizer of the scapholunate joint, disruption of this complex can lead to scapholunate diastasis and dorsal intercalated segmental instability (DISI) deformity.

1.3 The Role of the Carpal Ligaments

The dorsal and volar ligamentous complexes surrounding the wrist are anatomically and functionally distinct. The stout volar capsular ligaments are a complex series of condensations in the thick volar capsule.6,7 In contrast, there are only two named dorsal ligaments: the dorsal radiocarpal and dorsal intercarpal (DIC) ligaments. The remainder of the dorsal capsule is extremely elastic.

Fig. 1.5 The microstructure of the distal radius resembling an arch bridge.(Copyright © Gregory Bain, MD)

Fig. 1.6 The “multiple rings” of the wrist.(Copyright © Gregory Bain, MD)

Both Melone and Medoff described the importance of the ligamentous attachments of the distal radius.8–11 Melone highlighted the role of the two medial fragments for the articular function: “the medial complex” and its strong ligamentous attachments.10 Medoff recognized the contributions of ligaments to fracture displacement, and described radiocarpal instability and the contribution of ligament avulsion to the creation of “rim” fragments, leading to catastrophic failure of fixation.11

In our study by Mandziak et al,12 we performed CT mapping of 100 distal radius intra-articular fractures and identified that fracture lines were significantly more likely to occur between the ligament insertions (▶Fig. 1.7).6,7 In low-energy injuries, the fractures almost never include the ligament attachments but are between the ligaments. High-energy injuries are more random and reflect the forces placed on the wrist.

The ligaments are designed to resist tension, which is maximal at the extremes of motion. Bone is designed to take the compressive load and fail in tension. The ligaments play two key roles in the mechanism of fracture.

Our study, however, suggests that ligament insertion points may be protective for DRFs, as most fracture lines avoided these sites. This would correlate with the role of ligamentotaxis with fracture reduction. In the exception of the isolated “die-punch” fracture, ligamentotaxis reduces distal radius morphology. Even in cases of extreme comminution, an initial almost anatomical reduction may be possible by the creation of radiocarpal ligament tension across the joint. This would not be possible in the setting of radiocarpal ligament avulsion. Failure of the microarchitecture and the intraosseous arches may lead to later collapse—hence the high rate of redisplacement in fractures with comminution in osteoporotic bone.13 “Bridge plating” is an example of ligamentotaxis in the case of articular comminution. The “bridge” is used to maintain ligamentotaxis and neutralize deforming forces before osseous union occurs.

Fig. 1.7 Fractures most commonly involve the interligamentous zones 10, 2, and 6.(Copyright © Gregory Bain, MD)

1.4 Fracture Initiation and Propagation

We hypothesized that the position of the wrist at injury and subsequent position of the carpus initiates the fracture, leading to specific DRF patterns. We retrospectively reviewed a series of CT scans of two-part articular fractures of the distal radius. The DRF and specific points on the scaphoid and lunate were precisely mapped. The images were overlaid, and the proximity of the fracture to these points was measured and statistically analyzed (▶Fig. 1.8).

We used the classification of two-part fractures that Bain et al14 described (▶Fig. 1.9). Each of the defined fractures had an association with various parts of the lunate or scaphoid. For example, radial styloid oblique (RSO) fractures were associated with the volar ulnar aspect of the scaphoid. Intermediate column fractures with the radial border of the lunate. Dorsal ulnar corner (DUC) fractures with the dorsal radial aspect of the lunate. The volar ulnar corner and volar coronal (VC) fractures were associated with the position of the volar lunate and mid-position of the lunate and scaphoid, respectively.

There is an association between the position of the carpal bones and the type of articular fracture that occurs in the distal radius. The vast majority of fractures involve the scapholunate interval. We propose that a compressive load transmitted from the carpus initiates the fracture along the radial aspect of the lunate or the ulnar aspect of the scaphoid. Second, the fracture propagates to the periphery of the articular surface between the sites of ligamentous insertion (▶Fig. 1.10). Wrist position is important; radial deviation causes impaction of the scaphoid, and ulnar deviation—impaction of the lunate. A neutral position will cause corresponding impaction of the scaphoid and lunate.

This theory fits with the work of Pechlaner, who used a cadaveric model to produce a DRF and found concomitant lesions in 63% of cases. The majority of these lesions involved either disruption to the articular disc of the triangular fibrocartilaginous complex or the scapholunate ligament complex.15

1.5 Scapholunate Dissociation and Two-Part Fractures of the Distal Radius

There is a high incidence of intercarpal soft tissue injuries (34–54%) in association with DRF although the mechanism and relevance are unclear.16–18 Forward showed that intra-articular fractures were associated with a twofold increase in scapholunate dissociation as seen radiographically at 1 year.16 Mrkonjic reported long-term follow-up of untreated scapholunate injuries in association with DRF. No significant difference in functional scores was found; however, numbers in his series were low, no Geissler grade 4 injuries were included, and most injuries were in the nondominant hand.19

Fig. 1.8(a–e) Representative axial slices of the articular surface and proximal carpal row. Neighboring points on the scaphoid and lunate and a line of best fit are drawn to mark the orientation of the scapholunate joint to the articular surface.(Copyright © Gregory Bain, MD)

We performed a CT study, comparing of two-part DRFs with a control group. The significant increase in the scapholunate distance was noted in fracture subtypes RSO, DUC, sagittal ulnar column, and VC. In particular, both the dorsal and volar aspects of the scapholunate gap were significantly widened in the RSO and DUC groups. This may relate to the level or vector of force at the time of injury (▶Fig. 1.11). The scaphoid, lunate, or both bones as a unit may die-punch the distal radius articular surface, leading to scapholunate rupture and predictable fracture subtypes.

Fig. 1.10 Fracture mechanism of injury. Diagrammatic representation of initiation followed by propagation of articular distal radius fractures. (a) Force is transmitted from the hand—capitate—scaphoid or lunate to the distal radius. (b) Fracture of the articular surface of the radius is initiated at a point along the line of differential load (scapholunate interval). The lunate facet is compressed with ulnar deviation, while the scaphoid is not as loaded. (c) The fracture then propagates to the periphery of the articular surface, preferentially between protected areas of ligamentous insertion.(Copyright © Gregory Bain, MD)

1.6 Volar Marginal Rim Fractures

The volar marginal rim of the distal radius contains the lunate fossa and is the “keystone” for loadbearing through the distal radius. The volar rim also contains important volar radiolunate ligament insertions. These act as check reins, preventing volar subluxation and ulnar translocation of the carpus.

As previously described, the fracture can propagate between avulse radiocarpal ligaments. The volar marginal rim fracture represents the failure of the volar radiocarpal ligaments in tension and disruption of these important stabilizers to the rim of the distal radius (▶Fig. 1.12). The radioscaphocapitate (RSC) ligament acts as a secondary stabilizer to the scapholunate joint. Disruption of this ligament may unmask scapholunate injury as diastasis seen on preoperative imaging or under fluoroscopy.

Fig. 1.11 Scapholunate dissociation with different fracture subtypes: sagittal ulnar column (a) and radial styloid oblique (b). Note the position of the wrist (radial or ulnar deviation). The capitate hinges on either the lunate or scaphoid and drives into the scapholunate gap, causing scapholunate ligamentous injury and diastasis. The scaphoid, lunate, or the scapholunate unit impact the distal radius, initiating the fracture.(Copyright © Gregory Bain, MD)

Fig. 1.12(a) The mechanism of injury is often a fall on an outstretched hand, with hyperextension (1), which produces a tension band effect of the volar carpal ligaments (2), producing a localized impaction of the carpus on the radius (3). This causes initiation of a fracture (4) and subsequent fracture propagation (5). The volar plating is designed to provide a buttress of the volar fragments. If these fragments are small or osteoporotic, they can “flow” over the top of the buttress wall (1) and produce a volar collapse of the carpus (2). (b) If the fracture is not reduced and buttressed, the ligaments remain attached to the volar rim fragment, which determines the settling position of the carpus.(Copyright © Gregory Bain, MD)

We performed a retrospective radiological review of 25 volar marginal rim fractures and then compared to a control group of 25 consecutive intra-articular fractures not involving the volar rim.

Volar rim fractures have significantly higher incidence of scapholunate instability (48 vs. 20%), DISI deformity (44 vs. 20%), ulnar styloid fracture (88 vs. 68%), and ulnar translocation of the carpus (20 vs. 8%).

Following fixation, the volar rim fractures had a significantly higher incidence of scapholunate diastasis (48 vs. 20%) and failure of fixation (24 vs. 0%) (▶Fig. 1.13).

Distal radius plate design has evolved to attempt to capture the volar marginal rim fragment. Despite the placement of these plates distal to the watershed line, failure of the carpus can still occur (▶Fig. 1.14). This can be due to very distal comminuted avulsion fragments not being identified at the time of surgery or separation of the ligamentous attachment from the fragment. In these instances, we recommend fragment-specific hook or pin plates (▶Fig. 1.15) and ligament repair or reinforcement through transosseous repair or suture anchor fixation.

Fig. 1.13 Volar rim fractures have a higher incidence of volar instability (white arrow, showing volar subluxation of the carpus), scapholunate instability, and loss of fixation.

Fig. 1.14 Specific volar rim plating. Despite initial capture and support of the lunate fossa fragment, the carpus has subluxated volarly and ulnocarpal translocation has occurred.

Fig. 1.15 Fragment-specific fixation of the volar rim. Note the ligamentous origins on the distal radius in relation to the fracture.(Copyright © Gregory Bain, MD)

1.7 A Biomechanical Model for Distal Radius Fracture

We propose a uniting theory incorporating the findings of our studies with the published literature. The fracture event occurs as two distinct stages: fracture initiation followed by propagation.

When the patient falls on the outstretched hand, the wrist is taken past the normal physiological arc of motion. In a dorsally displaced fracture, the volar ligaments and flexor tendons become taut, acting as a tension band, which accentuates the compressive force on the distal radius articular surface.

Force is transmitted from the hand through the midcarpal joint predominantly by the capitate to the proximal carpal row over the scapholunate interval. With the wrist in extension and ulnar deviation, the force is transmitted to the lunate and then the lunate facet. With the wrist in extension and radial deviation, the force is transmitted to the scaphoid and then to the scaphoid facet (▶Fig. 1.10).

When there is disparity between load transmitted across the radiocarpal joint by the scaphoid and the lunate, a line of differential load exists along the scapholunate interval (SLI). Similar to the industrial die-punch analogy where sheet metal fails at the margin of the die, the distal radius subchondral bone plate fails in compression along this line of differential load. In this manner, articular fractures are initiated along the margin of the distal radius corresponding to the scapholunate interval. The scapholunate ligament complex can undergo stretch or complete rupture, depending on the magnitude and direction of force propagation. Intact secondary stabilizers, including the RSC, DRC, DIC, and STT ligaments, will prevent scapholunate diastasis. If there is compromise to these insertion points on the distal radius, such as in the context of a volar marginal fracture, static instability and diastasis will result. The specific point along the SLI ligament depends on a number of variables, including wrist position at the time of injury and both the magnitude and direction of the external force.

The energy of the fracture then dissipates throughout the subchondral bone plate, propagating along the path of least resistance to the periphery of the articular surface, fracturing between protected areas of ligamentous insertion. Predictable articular osteoligamentous fragments are created (▶Fig. 1.8).

In extreme wrist extension, the predominant force on the wrist is tensile over the volar carpal ligament complex. In this case, an avulsion fracture of the volar carpal ligaments will occur, leading to a volar marginal rim fracture. If the wrist is in radial deviation at the time of impact, the ulnar-sided short radiolunate is under most tension and likely to avulse. If the wrist is in ulnar deviation, the long radiolunate or RSC will avulse. After impact, the wrist settles; the lunate flexes and the carpus subluxates volarly (▶Fig. 1.12).

Fracture reduction methods rely on ligamentotaxis, creating a tensile force on the ligaments attached to the fracture fragments. This allows the fragments to realign in their anatomical position. It is imperative when performing surgery on distal radius malunion, therefore to respect this principle and avoid soft tissue stripping of these ligamentous insertions.

1.8 Summary

DRFs occur in low energy in compromised osteoporotic bone and high energy in younger patients. The distal radius functions as an “arch bridge”; its microarchitecture is a complex evolutionary design and resembles other common engineering structures used to absorb and transmit load safely.

Distal radius follows a predictable sequence of events from initiation through propagation. The bone fails in tension, compression, or both. The fracture pattern is dependent on the vector of force and position of ligaments. Fracture fixation as described in the following chapters should, therefore, respect the pathomechanics of the fracture and the role of the soft tissue stabilizers.

References

[1] Singh M, Nagrath AR, Maini PS. Changes in trabecular pattern of the upper end of the femur as an index of osteoporosis. J Bone Joint Surg Am 1970;52(3):457–467

[2] Bain GI, MacLean SBM, McNaughton T, Williams R. Microstructure of the Distal Radius and Its Relevance to Distal Radius Fractures. J Wrist Surg 2017;6(4):307–315

[3] Bain GI, MacLean SBM, McNaughton T, Williams R. Erratum: Microstructure of the Distal Radius and Its Relevance to Distal Radius Fractures. J Wrist Surg 2017;6(4):e1–e2

[4] Roth L, Clark A. Understanding Architecture: Its Elements, History, and Meaning. Colorado, USA: Westview Press; 2013

[5] Kuhlmann JN, Luboinski J, Laudet C, et al. Properties of the fibrous structures of the wrist. J Hand Surg [Br] 1990;15(3):335–341

[6] Berger RA. The ligaments of the wrist. A current overview of anatomy with considerations of their potential functions. Hand Clin 1997;13(1):63–82

[7] Berger RA. The anatomy of the ligaments of the wrist and distal radioulnar joints. Clin Orthop Relat Res 2001(383):32–40

[8] Melone CP Jr. Articular fractures of the distal radius. Orthop Clin North Am 1984;15(2):217–236

[9] Melone CP Jr. Open treatment for displaced articular fractures of the distal radius. Clin Orthop Relat Res 1986(202):103–111

[10] Melone CP Jr. Distal radius fractures: patterns of articular fragmentation. Orthop Clin North Am 1993;24(2):239–253

[11] Medoff RJ. Essential radiographic evaluation for distal radius fractures. Hand Clin 2005;21(3):279–288

[12] Mandziak DG, Watts AC, Bain GI. Ligament contribution to patterns of articular fractures of the distal radius. J Hand Surg Am 2011;36(10):1621–1625

[13] Mackenney PJ, McQueen MM, Elton R. Prediction of instability in distal radial fractures. J Bone Joint Surg Am 2006;88(9):1944–1951

[14] Bain GI, Alexander JJ, Eng K, Durrant A, Zumstein MA. Ligament origins are preserved in distal radial intraarticular two-part fractures: a computed tomography-based study. J Wrist Surg 2013;2(3):255–262

[15] Pechlaner S, Kathrein A, Gabl M, et al. [Distal radius fractures and concomitant lesions. Experimental studies concerning the patho-mechanism] Handchir Mikrochir Plast Chir 2002;34(3):150–157

[16] Forward DP, Lindau TR, Melsom DS. Intercarpal ligament injuries associated with fractures of the distal part of the radius. J Bone Joint Surg Am 2007;89(11):2334–2340

[17] Lindau T, Arner M, Hagberg L. Intraarticular lesions in distal fractures of the radius in young adults. A descriptive arthroscopic study in 50 patients. J Hand Surg [Br] 1997;22(5):638–643

[18] Geissler WB, Freeland AE, Savoie FH, McIntyre LW, Whipple TL. Intracarpal soft-tissue lesions associated with an intra-articular fracture of the distal end of the radius. J Bone Joint Surg Am 1996;78(3):357–365

[19] Mrkonjic A, Lindau T, Geijer M, Tägil M. Arthroscopically diagnosed scapholunate ligament injuries associated with distal radial fractures: a 13- to 15-year follow-up. J Hand Surg Am 2015;40(6):1077–1082

2 Radiology of the Fractured Radius

Mark Ross, Patrick Groarke

Abstract

This chapter provides guidelines for the radiographic assessment of distal radius fractures. We discuss plain radiographic parameters and their relationship in predicting stability and outcome and determining the adequacy of reduction and fixation strategy where indicated. We will review how to interpret computed tomography in the different planes and the relevance of fragmentation patterns. The value of magnetic resonance imaging and other modalities in assessing the fractured distal radius will be reviewed.

Keywords: radiographs, stability, reduction, parameters, CT, MRI, fragments

2.1 Introduction

Radiographic assessment of the distal radius should be undertaken when the mechanism of injury and presence of deformity or bony tenderness leads to clinical suspicion of a fractured distal radius. Understanding the imaging that needs to be obtained is a key element in the surgeon’s ability to decide on appropriate management. The interpretation of the imaging is an even more important element in planning management, and if fixation is indicated, what fixation method should be employed. It is also critical to understand that each option in the imaging process provides very specific information, which may not be available in other images. In this way, prereduction radiographs (XRs) inform certain aspects, postreduction XRs provide different information, and each plane of computed tomography (CT) imaging is best suited for specific anatomic components of the injury pattern.

The functional demands of each patient differ. As a consequence, the age (physiologic as well as chronologic), employment, and lifestyle of each patient must be used to place the radiographic parameters into context. The goal of treatment is to provide a painless extremity with good function. In surgical decision-making, special attention should be given to the patient’s bone quality. In addition, elderly patients with low demands may tolerate greater variance in many of the radiographic parameters that will be discussed in this chapter. However, with increasing activity level and functional expectations in an aging population, it is increasingly difficult to predict what may be tolerated by elderly patients.1

One of the most challenging considerations is whether the fracture pattern (pre- or postreduction) is stable. That is, is this the position that the fracture will ultimately heal in? The injury (prereduction) XR is very important in determining stability as it provides more information about maximum displacement and the energy of the injury. It is vital that the surgeon considers this series of images when making clinical decisions. Wherever possible, every effort should be made to obtain and assess the injury film. Consideration should also be given to this issue when the fracture has undergone some form of traction or closed reduction prior to initial radiographic assessment as the degree of displacement may be underestimated. A careful history of the interventions following injury is, therefore, vital. Following reduction and institution of closed treatment, it may be possible, with careful attention to cast changes, to control dorsal tilt; however, it is frequent to see the recurrence of radial shortening back to the injury position; thus, this must be considered when deciding on management.

Both increasing age of patients and increasing obesity in younger patients2 have led to an increase in fractures that are comminuted. Comminuted fractures can be difficult to assess on plain XRs, but by applying the same system to evaluate them and with the proper interpretation of the CT, the surgeon can plan the fixation technique where indicated.

2.2 Plain Radiographs

Standard XRs are indicated in all suspected distal radius fractures (DRFs). We recommend XR before and after reduction. As noted above, the assessment of stability is best conducted using the injury (prereduction) XRs. Standard views include posteroanterior (PA) and lateral XR. Oblique views can also be helpful in bringing the volar portion of the radial and ulnar aspect of the radius as well as the dorsal ulnar corner (DUC) into view. These provide a two-dimensional image of a three-dimensional (3D) structure but understanding the normal parameters on each view can allow clarification of articular fragments even where CT images are not available. It is important to be able to determine what constitutes a true PA and lateral because many images can be rotated due to patient’s inability to position the arm correctly due to pain, and many parameters are validated in relation to the orthogonal XRs.

2.2.1 Injury (Prereduction) Radiographs

The value of these films should not be understated to those carrying out emergent management such as closed manipulation so as to discourage reduction before imaging. This can happen where a grossly deformed wrist presents. Clearly, if the skin is threatened or there are significant neurological symptoms and XRs cannot be obtained emergently, the restoration of gross alignment takes priority; however, careful documentation of the deformity should be made. Injury films can reveal small, nondisplaced, and intra-articular fragments. These fragments might not be visible after anatomical reductions and cast application, which might mask the severity of the fracture. The original displacement and angulation of the fracture can be an indicator of instability. In a study of 406 DRFs, initial displacement was associated with worse QuickDASH score, worse EQ-5D score, reduced grip strength, and reduced range of motion (ROM).3

2.2.2 Postreduction Radiographs

Although potentially obscured by cast material, these images guide where fragments lie in relation to each other and what type of fixation should be considered. In addition, they guide the adequacy of reduction although should not be used for determining the stability of the fracture and propensity for loss of position (▶Fig. 2.1).

2.2.3 Parameters Can Change with Time

Where nonoperative management is undertaken, follow-up XRs at 1- and 2-week intervals would be considered a minimum and we have observed ongoing loss of position out to 6 weeks and beyond in cast treatment.

CT is more accurate in measuring the change in dorsal angulation over time in DRFs when compared to XRs.4 However, the cost and high dose of radiation are prohibitive in most healthcare systems, and benefits from this increased accuracy have not been clarified.

2.2.4 Radiograph of the Opposite Side

In severely comminuted fractures, or where the fragments have been inadequately reduced, it might be difficult to establish what the patient’s normal parameters should be. An XR of the uninjured opposite side can be helpful for comparison. Coronal plane translation, as will be discussed later, can be guided by the uninjured side. Contralateral XRs can also give an indication to the energy load to failure of the distal radius by defining normal ulna variance for that patient, given the significant variance in radial length. Increased ulnar variance (loss of radial length) after fracture is also associated with reduced bone mineral density in the distal radius.5

Parameters may vary between populations but the difference is likely to lie within the ranges described below.6

2.2.5 Posteroanterior View

The ulnar border of the ulnar styloid should be continuous with the ulnar border of the shaft. Pronation or supination can result in the ulnar styloid being partially overshadowed by the distal ulna shaft. The radial border of the ulna shaft is concave on a true PA view. Moreover, if the shafts of the radius and ulna are seen to converge, this indicates pronation. A full pronation view has the effect of shortening the radius by at least 0.5 mm.

The PA view presents the carpal facet horizon. This is a radiodense line that represents the volar rim of the lunate facet and medial half of the scaphoid facet, in a radius with normal volar tilt. It extends ulnarward to the sigmoid notch. In a wrist with preserved volar tilt, the XR beam is tangential to the volar half of the articular surface (▶Fig. 2.2). The DUC and dorsal rim are distal to this horizon and less well visualized (▶Fig. 2.3). In a dorsally angulated fracture, the radiodense line will represent the dorsal rim and DUC as the XR beam will be tangential to it (▶Fig. 2.4). The main value of the carpal facet horizon is that a step-off in it will indicate an articular step-off, and understanding whether one is viewing the dorsal or volar half of the joint will help to locate that articular involvement.7

The other implication of the separate representation of the volar and dorsal aspects of the ulnar corner is where to measure ulnar variance and radial inclination from. It has been suggested that true radial length is represented by the average point between the dorsal and volar ulnar corner on the PA view. This may be termed the central reference point (CRP).7 Many studies published up until this point have failed to clarify their method for determining the measuring point for ulnar variance. Perhaps radial length may be a more reproducible measure of true shortening of the radius than ulnar variance because of this factor.

Fig. 2.1(a) Prereduction film demonstrates significant displacement and implies an unstable fracture. (b) Postreduction image demonstrates articular surface involvement more clearly.

Fig. 2.2 The radiograph (XR) beam is tangential to the volar half of the joint in an intact or undisplaced radius.

2.2.6 Lateral View

It should be taken in neutral rotation. On a true lateral XR, the pisiform is located directly over the distal pole of the scaphoid. If the pisiform lies dorsal to the distal pole of the scaphoid, the forearm is rotated into pronation.

Another method of ensuring the wrist is in neutral rotation and is to use the scaphopisocapitate relationship.8 This is described where the rotation of the wrist is set at a position in which the volar margin of the pisiform bone lies at the central third of the interval between the volar cortex of the scaphoid tubercle and volar capitate. Wrist position is also important although may be compromised by pain or deformity in the acute setting. Larsen et al defined the true lateral XR as when the long axis of the radius and third metacarpal bone are collinear in neutral rotation.9

Fig. 2.3 The denser line represents the volar rim when the radius is intact or not dorsally tilted.

Fig. 2.4 In the dorsally tilted radius, the denser line becomes the dorsal rim as it rotates into a tangential relationship to the radiograph (XR) beam.

Fig. 2.5 Carpal alignment with the distal radius is assessed using a line up the volar surface of the radial shaft, which should intersect the center of the head of the capitate.7

Carpal alignment is determined on the lateral. A line extending from the volar surface of the radial shaft (not the metaphysis) should bisect the center of rotation of the proximal pole of the capitate7 (▶Fig. 2.5).

2.3 Plain Radiographic Parameters

Radiographic parameters are assessed in terms of extra-articular alignment and intra-articular fragmentation/congruence to determine stability and acceptability of reduction.

Fig. 2.6 Significant dorsal comminution implies a higher energy injury that would have had more displacement at the time of injury and may be less stable.

In general terms, comminution is a key extra-articular factor in assessing fracture stability (▶Fig. 2.6