THE B.G.Weber F. Magerl EXTERNAL FIXATOR AO/ASIF-Threaded Rod System Spine-Fixator With a Chapter by Ch. Brunner Foreword by A. Sarmiento With 362 Partly Colored Figures Springer-Verlag Berlin Heidelberg New York Tokyo 1985 Prof. Dr. BERNHARD G. WEBER Dr. FRIEDRICH MAGERL Dr. CHRISTIAN BRUNNER Klinik für Orthopädische Chirurgie, Kantonsspital, CH-9007 St. Gallen Translated from the German by TERRY C. TELGER Tit1e of the German Edition B.G. WEBER' F. MAGERL: Fixateur exteme © Springer-Verlag Berlin Heidelberg 1985 ISBN- 13: 978-3-642-70017-0 ISBN-13: 978-3-642-70017-0 e-ISBN-13:978-3-642-70015-6 DOI: 10.1007/978-3-642-70015-6 Library of Congress Cataloging in Publication Data. Weber, B.G. (Bernhard Georg), 1927- . The external fixator. Translated from the German with title: Fixateur externe. Ineludes bibliographies and index. 1. External skeletal fixation (Surgery) 1. Magerl, F. (Friedrich), 1931- . II. Brunner, Christian Ferdinand, 1937- III. Title. IV. Title: Spine-fixator. [DNLM: 1. Fracture Fixation - methods. WE 185 W373e] RD103.E88W43 1985 617'.15 84-24045 This work is subject to copyright. All rights are reserved, whether the whole or parts of the material coneemed, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under § 54 of the German Law where copies are made for other than private use, a fee is payable to "Verwer tungsgesellschaft Wort", M unich. © by Springer-Verlag Berlin Heidelberg 1985 Softeover reprint of the hardeover 1st edition 1985 The use of general descriptive names, trade marks, etc. in this publication, even if the former are not especially identified is not be taken as a sign that such names as understood by the Trade Marks and Merchandise Marks Act, may accordingly be used freely by anyone. Reproduction of the figures: Gustav Dreher GmbH, Stuttgart 2124/3130-543210 Foreword Professor B.G. WEBER has once again and in a very timely fashion produced a superb book on an orthopaedic subject of great importance. "The Extemal Fixator" is the most comprehensive text on the subject in orthopaedic literature to date. Professor WEBER thoroughly discusses extemal fixation with c1arity, organization, profuse illustrations and roentgenograms. Professor WEBER acknowledges that the use of extemal fixation in orthopaedic surgery is not newand traces its history over the years. He points out c1early the fact that though at various times the "method" has experienced periods of disrepute, modem sophistication, improved technology and a better understanding of its philosophy have given the system a newand perhaps permanent place in the armamentarium of the orthopaedic surgeon. All methods of treatment have critics as well as supporters, and not infrequently the strongest criticisms are the result of poor understanding of the philosophy proposed and its proper implementation. Professor WEBER, in his carefully detailed and well illustrated book, has made it abundantly c1ear that the use of extemal fixators in the treatment of fractures must be c1early understood by the orthopaedic surgeon in order to obtain satisfactory clinical results. His discussion of its philosophy, pathomechanics and technology are most comprehensive and leave "no stone untumed" and because of this the book represents a most comprehensive text on the subject. I have long held the belief that immobilization in the treatment oflong bone fractures is unphysiological and that fracture care should avoid, as much as possible, rigid fixation of fracture fragments. I recognize, however, there are situations where the creation of a healthy environment in which controlled motion is present cannot be attained. Severely open fractures and certain nonunions are representative examples of that situation. It is primarily in these circumstances where rigid fixation may be the treatment of choice. Extemal fixation, as Professor WEBER has so well documented, is an excellent method to obtain osseous repair while maintaining function and cosmesis. AUGUSTO SARMIENTO, M.D. Professor and Chairman Department of Orthopaedics University of Southem California School of Medicine Preface The use of an external fixation device for the stabilization of bone fragrnents probably dates back to LAMBOTTE in 1902. But despite its long history, the external fixator has not gained the same degree of acceptance in fracture management as the" elosed" meth ods of BÖHLER, WATSON-JONES and SARMIENTO, or true internaI fixation. Operative fracture treatment itself was not widely practiced until it was popularized in 1958 by the Swiss Association for the Study ofInternal Fixation (ASIF). It is important to note that the principal authors of the ASIF technique, Drs. MÜLLER, ALLGÖWER and WILLENEGGER, have never represented their technique as the only "correet" one, and in the preface to their book Technique of Operative Fracture Management (Springer Verlag, 1963) they state, "We caution very strongly against internaI fixations performed without proper training, instrumentation and surgical asepsis ... " The potential risks of internaI fixation have sparked renewed interest in conservative treatment strategies, with the resuIt that SARMIENTO'S "functional bracing" technique is now practiced as widely as the ASIF method. But neither internaI fixation nor functional bracing is adequate for the management of the highly complex extremity injuries that are being seen with increasing frequency as a resuIt of motorcyele and other high-speed vehicular accidents (" Honda disease "). This accounts in large part for the many reeent artieles and books devoted to the subject of external skeletal fixation (BROOKER, EDWARDS 1979; UHTHOFF 1982; MEARS 1983; ACKROYD, O'CONNOR, DE BRUYN 1983). The shear volume of these publications suggests that the external fixator is being "rediscovered" in the English-speaking world after ANDERSON put the external fixation concept into practice in the United States in 1934. When the first ASIF book was published in 1963, Dr. MÜLLER and other Swiss orthopedic surgeons had already been practicing external fixation for some years - first in reconstructive orthopedics and later fracture management. The threaded-rod external fixator, for example, is described in the first ASIF book. At the Department of Orthopedic Surgery of Kantonsspital St. Gallen, Switzerland, external fixations with the threaded-rod device have become as routine as internaI fixa tions by the ASIF method. This" routineness" mayexplain why no major publications on external fixation have yet appeared in Switzerland, and we feel that a text on the subject is overdue. In the present book we shall examine the use of the external fixator not only in fracture treatment, but also in other areas of orthopedic surgery. The following colleagues had a hand in the preparation of the book: Mrs. URSULA OETLIKER and Mrs. MYRTHA ZWEIFEL, who undertook repeated typescript revisions with thireless diligence and technical expertise; KATRIN and HORsT SCHUMACHER, who pre pared the excellent drawings; and Mrs. MARIANNE SCHAFFNER, Mrs. DORIS CLERICI and Mrs. ANNELISE SPITZ, who prepared the photographic illustrations. I express special thanks to my elosest medical colleagues: Dr. FRITZ MAGERL, assis tant department head, who described the spin al external fixation device; and Dr. CHRIS TIAN BRUNNER, chief of pediatric orthopedics, who wrote a chapter on external fixations in children and adolescents. VIII Preface I am also grateful to my present and former straff eolleagues who "tended to busi ness" on the c1inieallevel. In his eapaeity as engineer and manufaeturer, Dr. h.e. ROBERT MATHYS has worked elosely with the Teehnieal Committee of the ASIF and with us to improve the quality of the surgieal armamentarium. His work is gratefully aeknowledged. Finally, I express thanks to the staffat Springer-Verlag, who onee again did outstand ing work in the publieation of this text. St. Gallen, Summer, 1984 B.G. WEBER Contents Preamble. B.G. WEBER . . . . . . . . . . . . . . . . . . . . . . . . .. 1 The ASIF Threaded External Fixator in General Orthopaedic and Trauma Surgery of the Extremities A General Part. B.G. WEBER 4 1 Introduction . . . . . . 4 2 The History of External Fixation 6 3 Bone Healing in the Presenee of an External Fixator 7 3.1 Healing of a Diaphyseal Fraeture 9 3.1.1 Primary Healing of the Cortex 9 3.1.2 Seeondary Healing of the Cortex 9 3.1.3 Nonunion . . . . . . . . . . 12 3.1.3.1 Pathogenesis of Vaseular Nonunion 12 3.1.3.2 Pathogenesis of Avaseular Nonunion 14 3.2 Healing of Caneellous Bone .. .. 14 3.2.1 Primary Healing of Caneellous Bone 14 3.2.2 Seeondary Healing of Caneellous Bone 14 3.2.3 Nonunion of Caneellous Bone 14 3.2.3.1 Pathogenesis of Vaseular Nonunion . 14 3.2.3.2 Pathogenesis of Avaseular Nonunion 14 3.3 Healing of Nonunions . . . . . . 20 3.3.1 Healing of a Vaseular Nonunion 20 3.3.2 Healing of an Avaseular Nonunion 20 3.3.3 Healing of a Nonunion with Bone Loss 20 4 Goals of Treatment with the External Fixator 26 4.1 Lengthening Frame . 26 4.2 Neutralization Frame 26 4.3 Compression Frame 26 4.4 Soft-Tissue Frame 26 B On the Biomechanics of External Fixation. B.G. WEBER 27 1 Intrinsie Stability of the External Fixator . . . . . . 27 2 The External Fixator and Bone as a Composite System 28 2.1 Extemal Fixation without Interfragmental Contaet 28 2.2 Extemal Fixation with Interfragmental Contaet . . 28 2.3 Extemal Fixation with Interfragmental Compression 31 2.4 Biomeehanies and Seleetion of the Frame .... 32 X Contents 3 Stress Transfer with the External Fixator 34 3.1 Stress Transfer with the Neutralization and Lengthening Frame 34 3.2 Stress Transfer in the Presence of Bone Contact 34 3.2.1 Stress Transfer with a Bilateral Compression Frame . 34 3.2.2 Stress Transfer with a Unilateral Compression Frame 34 3.2.2.1 "Prebending" of the Rod . . . . . . . . 34 3.2.2.2 "Prebending" of the Bone . . . . . . . . . . . 37 3.2.2.3 Axial Compression with a "Spreading Rod" . . . 37 4 Means of Augmenting the Stability of the External Fixator 38 4.1 Increasing the Number of Pins or Screws 38 4.2 Placement of the Pins and Screws 38 4.3 Increasing the Number of Rods . 38 4.4 The Double-Frame Configuration 40 4.5 The Biplanar Frame ..... 41 5 Improving the Anchorage of Pins and Screws in Bone 42 6 Restoring the Compressive Strength of Bone in the Absence of Interfragmental Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.1 Restoring Bone Contact by Shortening .............. 45 6.2 Restoring Bone Contact by Interposing a Pressure-Resistant Bone Graft 46 6.3 Restoring Bone Contact by Adjunctive InternaI Fixation 46 6.3.1 Lag Screw pIus External Fixation . . . . . . . . . 47 6.3.2 AntigIide Plate pIus External Fixation . . . . . . . 48 6.4 Restoring Bone Contact by Cancellous Bone Grafting 49 6.5 Restoring Bone Contact by Transverse Compression 51 6.6 Restoring Bone Contact by Fragment Manipulation . 51 7 Sagittal or "Intermediate" Screw Placement in Unilateral External Fixation of the Tibia .................. . 52 8 Summary of the Biomechanics of External Fixation 53 8.1 The External Fixator and Bone . 53 8.2 Unilateral or Bilateral Frame . . 53 8.3 Elasticity of the External Fixator 53 e The Threaded External Fixator. Instrumentation. B.G. WEBER 54 1 Introduction 54 1.1 Requirements of the External Fixator 54 1.2 The External Fixator of the ASIF . . 54 2 The Elements of the Threaded External Fixator 55 2.1 Steinmann Pins . . . . . . . . . . . 55 2.2 Schanz Screws . . . . . . . . . . . 55 2.3 The 4.5-mm and 3.5-mm Cortex Screws 55 2.4 Drill Bits, Drill Sleeyes and Taps 56 2.5 Clamps for Steinmann Pins, Schanz Screws, 4.5-mm and 3.5-mm Cortex Screws 56 2.6 Threaded Rods 56 2.7 Nuts 56 2.8 Siider Bar 56 Contents XI 2.9 Additional lnstruments and lmplants 58 2.10 Special lnstruments 58 3 The Threaded Minifixator 59 D Operative Technique for the Threaded External Fixator. B.G. WEBER 60 1 The Special Characteristics of the Threaded External Fixator 60 2 Errors of Pin and Screw lnsertion . . 60 2.1 Technique for Steinmann Pins 61 2.2 Technique for Schanz Screws 63 2.3 Technique for Cortex Screws 64 3 Reduction 66 3.1 Concept. 66 3.2 Technique 68 4 The Application of a Bilateral Frame 69 4.1 Pin Placement 69 4.2 Pin lnsertion . . . . 70 4.3 Assembling the Frame 72 4.4 Reinforcing the Frame 72 4.5 Finishing the Frame 72 5 The Application of a Unilateral Frame 74 5.1 Placement of the Schanz Screws 74 5.2 Screw lnsertion . . . . . . . 75 5.3 Assembling the Unilateral Frame 78 5.4 Reinforcing the Frame 79 5.5 Finishing the Frame ..... 79 E Teehniques for Reinforeing the External Fixator. B.G. WEBER 80 1 lncreasing the Number of Rods . . . . . . . . . . . . . 80 2 Mounting Additional Rods in a Perpendicular Configuration 80 3 Stability of the Unilateral Frame .... 81 4 Restoring Bone Contact . . . . . . . . 83 5 Stability Enhancemerit and Frame Design 85 F Situations Requiring a Special Operative Technique. B.G. WEBER 86 1 Stabilization of Short Fragments ............ . 86 2 Diagonal Bracing Rod . . . . . . . . . . . . . . . . . . 87 3 Adding Single Clamps to the Frame, and Transverse Compression 88 G Axial Correetions. B.G. WEBER 89 1 Axial Corrections in the Bilateral Frame . 89 2 Axial Corrections in the Unilateral Frame 93 3 Axial Corrections with the Aid of an External Frame 93 H Loeal Care Following Frame Applleation. B.G. WEBER 94 1 Postoperative Care 94 2 Further Supervision . . . . . . . . . . . . . . . 95 XII Contents I Duration of External Fixation, and Removal of the External Fixator. B.G. WEBER 96 1 General Duration of External Fixation . . . 96 2 Early Removal of Individual Pins or Screws 96 3 Staged Removal of Combined Frames . . . 97 4 Removal of the External Fixator ..... 97 5 "Dynamization" of External Fixator Frames 99 K Instrumentation Used with the Threaded External Fixator. B.G. WEBER 100 1 General . . . . . . . . . . 100 2 Threaded External Fixator Sets 100 L The Threaded External Fixator in Adults. Clinieal Examples. B.G. WEBER 106 1 Introduction 106 2 Humerus 111 3 Elbow 115 4 Wrist 118 5 Pelvis 125 6 Femur 127 7 Knee 139 8 Tibia 146 9 Ankle 209 10 Soft Tissues 231 M The Threaded External Fixator in Children and Adolescents. CH. BRUNNER 243 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .. 243 2 The External Fixator for Severe Open Fractures in Children, Infected Fractures and Infected Nonunions . . . . . . . . . . . . . . . . . . 244 3 Corrective Osteotomies of the Proximal Femur in Small Children 252 3.1 Instrumentation and Technique . . . 252 3.2 The Technique Practiced at our Center 252 3.3 Indications and Examples ..... 254 4 Lengthening Osteotomies in Children and Adolescents 259 4.1 Introduction . . . . . . . . . . . . 259 4.2 Lengthening Osteotomy of the Humerus 259 4.3 Lengthening Osteotomy of the Femur . 261 4.4 Lengthening of the Tibia ..... . 269 5 Corrective Osteotomy for Staged Limb Lengthening 273 5.1 Staged Supracondylar Lengthening of the Femur 273 5.2 Corrective Osteotomy of the Proximal Tibia 275 5.3 Supramalleolar Corrective Osteotomy of the Tibia 281 6 Special Problems 284 N Concluding Remarks. B.G. WEBER .................... 287