Ebook Imaging of orthopaedic fixation devices and prostheses: Part 1

(BQ) Part 1 book Imaging of orthopaedic fixation devices and prostheses presents the following contents: The knee, the femoral shaft, the pelvis and hips, spinal instrumentation, common orthopaedic terminology and general fixation devices, imaging techniques, tibial and fibular shafts.

Imaging of Orthopaedic Fixation Devices and Prostheses Imaging of Orthopaedic Fixation Devices and Prostheses Thomas H Berquist, MD, FACR Professor of Diagnostic Radiology Mayo Clinic College of Medicine Rochester, Minnesota; Consultant in Diagnostic Radiology Mayo Clinic Jacksonville Jacksonville, Florida Acquisitions Editor: Lisa McAllister Managing Editor: Ryan Shaw Project Manager: Alicia Jackson Manufacturing Coordinator: Kathleen Brown Senior Marketing Manager: Angela Panetta Designer: Stephen Druding Cover Designer: Larry Didona Production Services: Laserwords Private Limited, Chennai, India © 2009 by LIPPINCOTT WILLIAMS & WILKINS, a WOLTERS KLUWER business 530 Walnut Street Philadelphia, PA 19106 USA LWW.com All rights reserved This book is protected by copyright No part of this book may be reproduced in any form by any means, including photocopying, or utilized by any information storage and retrieval system without written permission from the copyright owner, except for brief quotations embodied in critical articles and reviews Materials appearing in this book prepared by individuals as part of their official duties as U.S government employees are not covered by the above-mentioned copyright Printed in China Library of Congress Cataloging-in-Publication Data Imaging of orthopaedic fixation devices and prostheses / editor, Thomas H Berquist p ; cm Includes bibliographical references and index ISBN-13: 978-0-7817-9252-3 (alk paper) ISBN-10: (invalid) 0-7817-9252-3 (alk paper) Orthopedic apparatus—Imaging Musculoskeletal system—Diseases—Imaging Musculoskeletal system— Diseases—Surgery I Berquist, Thomas H (Thomas Henry), 1945[DNLM: Musculoskeletal Diseases—diagnosis Diagnostic Imaging Musculoskeletal Diseases—surgery Orthopedic Fixation Devices WE 141 I301 2009] RD755.5.I38 2009 617 9—dc22 2008024236 Care has been taken to confirm the accuracy of the information presented and to describe generally accepted practices However, the authors, editors, and publisher are not responsible for errors or omissions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the publication Application of this information in a particular situation remains the professional responsibility of the practitioner The authors, editors, and publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accordance with current recommendations and practice at the time of publication However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any change in indications and dosage and for added warnings and precautions This is particularly important when the recommended agent is a new or infrequently employed drug Some drugs and medical devices presented in this publication have Food and Drug Administration (FDA) clearance for limited use in restricted research settings It is the responsibility of health care providers to ascertain the FDA status of each drug or device planned for use in their clinical practice To purchase additional copies of this book, call our customer service department at (800) 638-3030 or fax orders to (301) 223-2320 International customers should call (301) 223-2300 Visit Lippincott Williams & Wilkins on the Internet: at LWW.com Lippincott Williams & Wilkins customer service representatives are available from 8:30 am to pm, EST 10 I dedicate this text to my loving wife, Mary, for her continued support and understanding Preface In 1995 we published an Atlas of Orthopaedic Appliances and Prostheses This was a work dedicated to bridging the gap between orthopaedic surgeons and imagers I have continued to dedicate efforts to improve the understanding of orthopaedic procedures and ‘‘what the surgeon needs to know’’ when ordering preoperative and postoperative imaging studies Orthopaedic instrumentation and prostheses continue to evolve, making it difficult for imagers to keep up with all possible implants that may appear on radiographs or other imaging modalities With this in mind, it is essential for surgeons and radiologists to work closely and we, as imagers, need to become familiar with the instrumentation systems our surgeons prefer This edition is designed to be more concise than the prior atlas with no attempt to demonstrate every possible fixation device or prostheses We review the important clinical and image features of orthopaedic devices including clinical concepts and patient selection, the normal appearance of orthopaedic devices and the image features, and most appropriate modalities for evaluating complications Chapter is a concise review of image modalities that may play a role in evaluation of orthopaedic fixation devices and prostheses Chapter provides a list and definitions of commonly used orthopaedic terms and an overview of general fixation devices including screws, plates, intramedullary nails, wires and cables, and soft tissue anchors These chapters serve to reduce redundancy in later chapters where these devices may be used Chapters through 13 are anatomically oriented and focus on fixation devices, prostheses, and procedures for a given anatomic region Emphasis is placed on indications, clinical data and decision making, as well as preoperative and postoperative imaging and complications Each chapter includes trauma, orthopaedic classifications where appropriate, and joint replacement and other common orthopaedic procedures related to the anatomic region covered in the chapter Chapter 14 reviews clinical data, staging, and preoperative and postoperative imaging in patients with musculoskeletal neoplasms This text will be most useful to practicing radiologists and radiologists in training Other physicians who deal with orthopaedic problems will also find the information provided in this text extremely useful vii Acknowledgments Preparation of this text required the support of numerous individuals and colleagues I first wish to thank my colleagues in musculoskeletal imaging at Mayo Jacksonville, Laura Bancroft, Mark Kransdorf, and Jeffrey Peterson for their support and assistance in providing the necessary images needed to fulfill the mission of this text I also want to thank my colleagues in orthopaedic surgery, Mark Broderson, Stephen Trigg, Cedric Ortiguera, Peter Murry, Mary O’Connor, Kurtis Blasser, and Joseph Whalen for their consultative support Daniel Huber and John Hagen were instrumental in providing images and art required to demonstrate anatomy, normal and abnormal image features for devices described in this text The vendors of orthopaedic devices were also very helpful in providing photographs and artwork to assist with demonstration of devices and their indications to use along with the images in this text Finally, I wish to thank Ryan Shaw, Lisa McAlliser, and Kerry Barrett from Lippincott Williams & Wilkins for their assistance and support with this project ix I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S A ◗ Fig 7-10 B A: Hex-Fix unilateral fixator External fixation allows fragment position (B) to be adjusted (C) and access to open wounds D: Ilizarov ring fixator (Courtesy Smith and Nephew Richards, Memphis, Tennessee.) 340 C CHAPTER ● Tibial and Fibular Shafts SUGGESTED READING Behrens F General theory and principles of external fixation Clin Orthop 1989;241:15–23 Finkemeier CG, Schmidt AH, Kyle RF, et al A prospective randomized study of intramedullary nails inserted with and without reaming for treatment of open and closed fractures of the tibial shaft J Orthop Trauma 2000;14:187–193 Giannoudis PV, Papkostidis C, Roberts C A review of management of open fractures of the tibia and femur J Bone Joint Surg 2006;88B:281–289 Lang GJ, Cohen BE, Bosse MJ, et al Proximal third tibial fractures Clin Orthop 1995;315:64–74 Mashru RP, Herman MJ, Pizzutillo PD Tibial-shaft fractures in children and adolescents J Am Acad Orthop Surg 2005;13: 345–352 McGraw JM, Lim EV Treatment of open tibial-shaft fractures External fixation and secondary intramedullary nailing J Bone Joint Surg 1988;70A:900–911 Smith WR, Ziran BH, Angel JO, et al Locking Plates: Tips and tricks J Bone Joint Surg 2007;89A:2298–2307 Vallamshetla VRP, De Silva U, Bache CE, et al Flexible intramedullary nails for unstable tibial fractures in children J Bone Joint Surg 2006;88B:536–540 ◗ Postoperative Imaging and Complications D ◗ Fig 7-10 Complications following fractures of the tibial shaft with or without associated fibular fractures are related to the extent (Continued ) ◗ Fig 7-11 Anatomic illustration of the leg with axial anatomy at three levels showing the regions for safe (S ) pin placement at these levels Sciatic nerve S Popliteal artery Tibial nerve Plantaris Common peroneal nerve Gastrocnemius S Soleus Peroneus longus Flexor digitorum longus S Tendon of tibialis posterior Flexor retinaculum Tendon of peroneus brevis Achilles tendon Superior peroneal retinaculum Superficial layer 341 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S of osseous and soft tissue injury and the treatment method or methods selected In any case, close radiographic followup is required to assure stable position of the fragments (see Fig 7-18) Other complications require additional imaging techniques depending on the suspected problem Infection Infection is one of the most difficult problems, especially with open wounds The incidence varies significantly with the type of injury (Gustilo and Anderson type I—1.4%; type II—3.6%, and type III—22.7%) The incidence of infection also varies with treatment selection Deep infection occurs in 16.2%, pin tract infection in 32%, and chronic osteomyelitis develops in 4.2% of patients treated with external fixation (see Fig 7-19) Deep infections in patients treated with unreamed (7% to 33%) and reamed nails (6.4%) also vary, although the incidence of chronic osteomyelitis is only 0.7% with either method The data is somewhat skewed because patients with the worst open wounds are more likely to be treated, at least initially with external fixation Imaging of infections also varies depending on the type and extent of infection Pin tract infections may be identified on serial radiographs or if the pin is removed by fluoroscopically positioned images down the barrel of the tract demonstrating ring sequestra Deep infections, even in the presence of fixation devices, may be studied with MRI, computed tomography (CT), or combination radionuclide studies (see Fig 7-20) Multiple approaches have been used with radionuclide imaging including three-phase bone scans with Technetium Tc 99 m A ◗ Fig 7-12 Complex fracture with open wound (Gustilo and Anderson type IIIA) Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate complex mid tibial and fibular shaft fractures Following external fixation with a ring fixator, the fragments, specifically the tibia, have been reduced (C) Radiographs months (D) later show the healed fractures 342 B CHAPTER Tibial and Fibular Shafts D C ◗ Fig 7-12 ● (Continued ) methylene-diphosphonate (MDP), technetium-labeled white blood cells, antigranulocyte antibody–labeled technetium, Indium In 111–labeled white blood cells, and more recently, F-18 fluorodeoxyglucose positron emission tomography (PET) imaging Technetium-labeled white blood cells disassociate at a rate of 5% to 7% per hour following injection This results in significant unwanted background activity PET studies report sensitivities of 92% and specificities in the 97% range (see Fig 4–80) In 111–labeled white blood cells remain the gold standard in our practice Sensitivity ranges from 84% to 96% with specificity exceeding 96% Delayed Union/Nonunion Delayed union or nonunion is not uncommon (Fig 7-13) The former occurs in 15% of distal tibial fractures in adults The incidence increases with more comminuted fractures In children, delayed union occurs in only 2% of patients with closed fractures but increases to 25% with open fractures Delayed union and nonunion also vary with treatment approaches Problems with union result in a second procedure in 68% of patients treated with external fixation Union rates are similar with reamed and unreamed intramedullary nails, although delayed union is reported in up to 22% The incidence of nonunion is higher (31%) for proximal third tibial fractures treated with intramedullary nails Loss of reduction and refracture occur in more than 20% of patients treated with external fixation Imaging of delayed union and nonunion can be accomplished with serial radiographs However, CT with reformatted images is preferred in the coronal and sagittal planes to evaluate callus and healing (Fig 7-20) Malunion Poor results with alignment, rotation, leg length, and angulation also occur Malunion with external fixation may occur in up to 20% of patients compared to 10% treated with unreamed and 6% treated with reamed intramedullary nails The incidence is higher (84%) in proximal third tibial fractures treated with intramedullary nails and lower than any of the above-mentioned methods with plate fixation Serial radiographs are generally adequate for evaluation of malunion Implant Failure Implant failure is uncommon, but as expected is more common with complex injuries (Fig 7-16) Implant fracture or loosening 343 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S ◗ Fig 7-13 Anteroposterior (AP) (A) and lateral (B) radiographs of a complex fracture Note the distal tibial fragment is externally rotated 90 degrees AP (C) and lateral (D) radiographs following external fixation demonstrate good alignment of the tibial fracture At months (E), there are signs of nonunion with sclerosis of the fracture margins Therefore, the fracture line was debrided and an intramedullary nail positioned (F) AP (G) and lateral (H) radiographs months later demonstrate that the fracture has healed A C 344 B D CHAPTER ◗ Fig 7-13 E F G H ● Tibial and Fibular Shafts (Continued ) 345 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S Patients may have paresthesias, pain, and decreased pulses Once diagnosed, patients are treated with fasciotomy to reduce the compartment pressure Neurovascular injuries may occur as isolated events due to the injury or treatment method in the absence of compartment syndrome Depending on the implants, MRI or CT may be useful for imaging these complications SUGGESTED READING A B ◗ Fig 7-14 Intramedullary nails A: Russell Taylor nail with screw holes at both ends to allow dynamic or static fixation B: Flexible Ender rod occurs in 2.7% of patients treated with external fixation, 3% of patients treated with reamed nails, and 12.4% of patients treated with unreamed nails (see Fig 7-21) Serial radiographs are adequate for detection of implant failure Giannoudis PV, Papakostidis C, Roberts C A review of the management of open fractures of the tibia and fibula J Bone Joint Surg 2006;88B:281–289 Gratz S, Rennen HHM, Boerman OC 99m Tc-HMPAOlabeled autogenous vs heterogenous leukocytes for imaging of infection J Nucl Med 2002;43:918–924 Lang GJ, Cohen BE, Bosse MJ, et al Proximal third tibial fractures Should they be nailed Clin Orthop 1995;315: 64–74 Mashru RP, Herman MJ, Pizzutillo PD Tibial-shaft fractures in children and adolescents J Am Acad Orthop Surg 2005; 13:345–352 McGraw JM, Lim EV Treatment of open tibial-shaft fractures External fixation with secondary intramedullary nailing J Bone Joint Surg 1988;70A:900–911 Okike K, Bhattacharyya T Trends in management of open fractures A critical analysis J Bone Joint Surg 2006;88A: 2739–2748 Termaat MF, Raijmakers PGHM, Scholten HJ, et al The accuracy of diagnostic imaging for assessment of chronic osteomyelitis: A systematic review and meta-analysis J Bone Joint Surg 2005;87A:2464–2471 Tornetta P, Templeman D Compartment syndrome associated with tibial fracture J Bone Joint Surg 1996;78A:1438– 1444 Webb LX, Bosse MJ, Castillo RC, et al Analysis of surgeon controlled variables in treatment of limb-threatening Type III open tibial diaphyseal fractures J Bone Joint Surg 2007; 89A:923–928 Zalavras CG, Marcus RE, Levin LS, et al Management of open fractures and subsequent complications J Bone Joint Surg 2007;89A:884–895 Compartment syndrome ◗ Compartment syndrome can occur with open and closed fractures with an incidence ranging from 1% to 9% The incidence is highest with more complex fractures Soft tissue injury and arterial injury may result in bleeding or edema in the four compartments of the leg The compartments include the anterior, lateral, superficial, and deep posterior compartments Increased pressure (>25 to 30 mm Hg) may result in ischemia Approximately 15% of adults have some degree of leg length discrepancy Leg length discrepancies are common problems with multiple etiologies The need for surgical intervention depends on multiple factors Discrepancy of cm or less can be managed with shoe lifts With this degree of discrepancy, abnormal gait results if not properly managed with orthotics Epiphysodesis of the uninvolved extremity can be performed 346 Leg Length Discrepancy CHAPTER A ● Tibial and Fibular Shafts B ◗ Fig 7-15 Anteroposterior (AP) (A) and lateral (B) radiographs following intramedullary nail fixation of a distal tibial fracture There are two distal screws with no proximal screws 347 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S ◗ Fig 7-16 Comminuted wedge fracture of the distal tibia reduced with internal fixation using a dynamic compression plate and screws There is an interfragmentary screw (arrow ) as well that has pulled out and extends into the anterior soft tissues A if the discrepancy is cm or less Step-cut osteotomy of the tibia may also be used for shortening More significant length discrepancies may require lengthening procedures B Neuromuscular disorders Poliomyelitis Spastic hemiplegia Spinal cord anomalies Etiologies of Leg Length Discrepancy Congenital Proximal focal femoral deficiency Developmental dysplasia of the hip Tibial hemimelia Congenital tibial bowing Hereditary exostoses Physeal abnormalities Blount disease Ischemic physeal arrest Trauma Slipped capital femoral epiphysis Hyperemia Post-traumatic overgrowth Chronic infection Inflammatory arthropathies Arteriovenous malformations 348 SUGGESTED READING Broughton NS, Olney BW, Menelaus MB Tibial shortening for leg length discrepancy J Bone Joint Surg 1989;71B: 242–245 Guichet JM, Spivak JM, Trouilloud P, et al Lower limblength discrepancy An epidemiologic study Clin Orthop 1991;272:235–241 Stricker SJ, Hunt T Evaluation of leg length discrepancy in children Int Pediatr 2004;19:134–142 ◗ Imaging Techniques Radiographic, CT, and MRI techniques have all been used to define leg length discrepancy Radiographic scanograms are CHAPTER A ● Tibial and Fibular Shafts B ◗ Fig 7-17 Anteroposterior (AP) (A) and lateral (B) radiographs following locking plate fixation of a mid tibial fracture in a patient with a knee arthroplasty There are associated fibular fractures ◗ Fig 7-18 External fixation of spiral fractures of the distal tibia and proximal fibula A: Radiograph following positioning of the fixation device B: Radiograph obtained the following day with loss of position and shortening A B 349 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S obtained with the patient supine and ruler between the legs Three separate exposures are made centered over the hips, knees, and ankles to avoid magnification This technique is most appropriate for older children who are able to maintain a fixed position during the exposures Radiographic scanograms are also suboptimal in patients with angular deformities Biplanar CT scanograms are more appropriate in patients with angular deformities or joint contractures CT studies can also be performed with lower radiation doses SUGGESTED READING Helms CA, McCarthy S CT scanograms for measuring leg length discrepancy Radiology 1984;151:802 Thaller PH, Baumgart R, Burghardt S, et al Digital imaging in lower limb bone deformities-standards and new perspectives Int Congr Ser 2005;1281:154–158 ◗ ◗ Fig 7-19 Radiographic spot image of an infected nonunion The external fixation device has been removed Treatment Options Treatment options vary with the underlying disorder and degree of leg length discrepancy As noted earlier, discrepancy of cm or less is treated conservatively Discrepancy of to cm may be treated with limb-shortening procedures Discrepancy of >5 cm A ◗ Fig 7-20 Tibial nonunion Anteroposterior (AP) (A) and lateral (B) radiographs demonstrate sclerosis along the fracture line in a patient with locking plate fixation C: Technetium Tc 99m methylene-diphosphonate (MDP) scan demonstrates intense uptake at the fracture site An indium In 111–labeled white cell scan was negative Coronal (D) and sagittal (E) reformatted computed tomographic (CT) scans clearly demonstrate the hypertrophic nonunion 350 B CHAPTER C ◗ Fig 7-20 Tibial and Fibular Shafts D E (Continued ) A ◗ Fig 7-21 ● B Anteroposterior (AP) (A) and lateral (B) radiographs of a fractured intramedullary nail 351 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S desired length with external fixator; stage 2—insertion of iliac bone graft when desired length achieved and plate and screw fixation; stage 3—plate removal and protected weight bearing Distraction epiphysodesis: External fixator applied with 0.25 mm of epiphyseal distraction four times a day until endpoint reached; best used in patients just before growth plate closure Ilizarov technique: Distraction osteogenesis; cortical osteotomy with controlled distraction to days after osteotomy at 0.25 mm every hours (see Fig 7-22) Callotasis: Gradual distraction after callus is evident on radiographs, usually 10 to 15 days; distraction at 0.25 mm every hours is more often treated with lengthening techniques Leg length discrepancy >5 cm is at higher risk for complications Shortening Procedures Epiphysodesis: Stapling or closing of the epiphysis of the longer limb; most optimal in patients with significant growth potential Step-cut osteotomy: Tibia shortened with stair step configuration osteotomy with screw fixation Fibular osteotomy at a different level Progressive shortening: Osteotomy with external fixation and reduction in length at mm per day increments until desired length achieved Lengthening Procedures Wagner technique: Stage 1—diaphyseal osteotomy with 0.5 to 1.0 cm distraction increased by mm per day to the SUGGESTED READING Abdlslam KM, Oleksak M, Saleh M Tibial shortening for correction of leg length discrepancy and deformity: A new technique J Pediatr Orthop 2003;12:264–268 Broughton NS, Olney BW, Menelaus MB Tibial shortening for leg length discrepancy J Bone Joint Surg 1989;71B: 242–245 Stricker SJ, Hunt T Evaluation of leg length discrepancy in children Int Pediatr 2004;19:134–142 Walker CW, Aronson J, Kaplan PA, et al Radiographic evaluation of limb-lengthening procedures AJR Am J Roentgenol 1991;156:353–358 ◗ ◗ Fig 7-22 Illustration of leg lengthening using an Ilizarov ring fixator with tibial corticotomy and distal fibular resection (Courtesy of Smith and Nephew Richards, Memphis, Tennessee.) 352 Imaging of Postoperative Complications Complications and incidence following limb discrepancy procedures vary widely in the literature However, there is agreement that major complications are reduced from the range 69% to 75% to the range 25% to 35% with increased surgical experience Complications increase with discrepancies that require >5 cm of correction Osseous complications include nonunion, malunion, fracture, joint deformities, pin loosening, and infection Angular deformities are more common with unilateral fixators compared to ring or hybrid external fixation systems Osseous infection is more common with larger threaded pins and is unusual with small wires used in ring fixators Soft tissue complications include diminished muscle function, neurovascular injury, and compartment syndrome and infection Serial radiographs can detect most osseous complications (see Fig 7-23) However, CT with coronal and sagittal reformatting is preferred to evaluate healing and callus formation Soft tissue complications may require angiography, CT, or MRI depending on the type of fixation in place Complex wire or pin configurations may cause too much image distortion on MR images CHAPTER A ● Tibial and Fibular Shafts B C ◗ Fig 7-23 Serial radiographs before (A) and after (B and C) removal of the external fixator A subtle fracture (arrow ) with varus angulation is present in B after fixator removal This was overlooked and marked varus angulation developed (C) (From Walker CW, Aronson J, Kaplan PA, et al Radiologic evaluation of limb-lengthening procedures AJR Am J Roentgenol 1991; 156:353–358.) 353 I M A G I N G O F O R T H O PA E D I C F I X AT I O N D E V I C E S A N D P R O S T H E S E S SUGGESTED READING Aronson J Limb-lengthening, skeletal reconstruction and bone transport with the Ilizarov method J Bone Joint Surg 1997; 79A:1243–1259 354 Paley D Current techniques in limb lengthening J Pediatr Orthop 1988;8:73–92 Walker CW, Aronson J, Kaplan PA, et al Radiologic evaluation of limb-lengthening procedures AJR Am J Roentgenol 1991; 156:353–358 ... The Elbow 535–578 12 The Radius and Ulna 579–592 13 Hand and Wrist 593–670 14 Musculoskeletal Neoplasms 6 71 712 Index 75 15 2 713 – 713 xi Imaging Techniques a ppropriate use of imaging techniques... agents include Fluorine -18 -deoxyglucose, L-methyl-carbon 11 -methronin, and oxygen 15 Fluorine -18 has a half-life of 11 0 minutes compared to the shorter half-life of 20 and 21 minutes, respectively,... Pelvis and Hips 15 3–220 The Femoral Shaft 2 21 250 The Knee 2 51 332 Tibial and Fibular Shafts 333–354 The Foot and Ankle 355–454 The Shoulder 455– 512 10 Humeral Shaft Fractures 513 –534 11 The Elbow