From the Department of Orthopaedics and Traumatology, and the Department of Pediatric Surgery, University of Helsinki; and the Research Institute of Military Medicine, Central Military Hospital, Helsinki FEMORAL SHAFT FRACTURES IN ADULTS: EPIDEMIOLOGY, FRACTURE PATTERNS, NONUNIONS, AND FATIGUE FRACTURES A clinical study Sari Salminen Academic dissertation To be presented with the permission of The Faculty of Medicine of the University of Helsinki, for public discussion in the Auditorium of the Töölö Hospital, Helsinki University Central Hospital, on June 29th, 2005, at 12 o’clock noon. Helsinki 2005 Supervised by Docent Ole Böstman, M.D., Ph.D. Department of Orthopaedics and Traumatology Helsinki University Central Hospital Helsinki, Finland Docent Harri Pihlajamäki, M.D., Ph.D. Department of Surgery and Research Institute of Military Medicine Central Military Hospital Helsinki, Finland Reviewed by Docent Matti U.K. Lehto, M.D., Ph.D. Coxa, Hospital for Joint Replacement Tampere, Finland Professor Erkki Tukiainen, M.D., Ph.D. Department of Plastic Surgery Helsinki University Central Hospital Helsinki, Finland To be discussed with Professor Heikki Kröger, M.D., Ph.D. Department of Orthopaedics and Traumatology Kuopio University Hospital Kuopio, Finland ISBN 952-91-8891-9 (bound) ISBN 952-10-2523-9 (PDF) Helsinki University Printing House Helsinki 2005 To my family 4 CONTENTS ABSTRACT ............................................................................................................... 7 LIST OF ORIGINAL PUBLICATIONS..................................................................... 8 ABBREVIATIONS ..................................................................................................... 9 1. INTRODUCTION ................................................................................................ 11 2. REVIEW OF THE LITERATURE......................................................................... 13 2.1. Definition of the femoral shaft .................................................................... 13 2.2. Anatomy of the femoral shaft ...................................................................... 13 2.3. Biomechanics of long bone fractures ........................................................... 17 2.4. Fracture healing, delayed union and nonunion of diaphyseal bone .............. 21 2.5. Classifications of femoral shaft fractures in adults ...................................... 22 2.6. Fracture mechanisms and injuries causing traumatic femoral shaft fractures ....................................................................................................... 24 2.7. Etiology of fatigue fractures of the femoral shaft ........................................ 26 2.8. Demography and incidence of femoral shaft fractures................................ 29 2.9. Location, morphology, and soft-tissue injuries of femoral shaft fractures ..... 32 2.10. Concomitant injuries associated with femoral shaft fractures ................... 35 2.11. Diagnosis and treatment of femoral shaft fractures ................................... 38 2.11.1. Clinical course ............................................................................... 38 2.11.2. Radiographic findings .................................................................... 39 2.12. Treatment of femoral shaft fractures in adults .......................................... 40 2.12.1. Development of conservative treatment of femoral shaft fractures ........................................................................................ 40 2.12.2. Traction ......................................................................................... 40 2.12.3. Cast bracing .................................................................................. 41 2.12.4. Development of operative treatment of femoral shaft fractures ... 42 2.12.5. Plate fixation .................................................................................. 45 2.12.6. External fixation ............................................................................ 45 2.12.7. Intramedullary nailing .................................................................... 46 2.12.7.1. Principle of intramedullary nailing ................................. 46 2.12.7.2. Technique of intramedullary nailing and aftertreatment .. 51 2.13. Outcome and complications of the treatment of femoral shaft fractures ..... 54 2.13.1. Fracture union ............................................................................... 54 2.13.2. Complications ................................................................................ 55 3. AIMS OF THE PRESENT STUDY ...................................................................... 65 4. PATIENTS AND METHODS ............................................................................... 66 4.1. Definitions used in the study (I, II, III, IV) ................................................. 66 4.2. Patient data (I, II, III, IV) ............................................................................ 68 5 4.3. Study arrangement (I, II, III, IV) ................................................................ 69 4.4. Fracture management (II, III, IV) ............................................................... 70 4.5. Follow-up time (II, II, IV) ........................................................................... 72 4.6. Statistical methods (I, II, III, IV) ................................................................ 72 5. RESULTS .............................................................................................................. 73 5.1. Demography of femoral shaft fractures in adults (I, II, III) ....................... 73 5.2. Injury mechanism (I, II, IV) or activity during fracture onset (III) ............ 75 5.3. Concomitant injuries (I, II, III, IV).............................................................. 79 5.4. Fracture characteristics (I, II, III, IV) ........................................................ 79 5.5. Outcome and complications of fracture treatment (II, III, IV) ................... 84 6. GENERAL DISCUSSION .................................................................................... 100 6.1. Incidence of femoral shaft fractures............................................................ 100 6.2. Injury season and injury mechanisms of femoral shaft fractures in adults .... 103 6.3. Concomitant injuries related to femoral shaft fractures in adults................. 103 6.4. Morphology of femoral shaft fractures in adults ......................................... 104 6.5. Treatment, outcome, and complications of femoral shaft fractures in adults ............................................................................................................. 105 6.6. Prevention of femoral shaft fractures .......................................................... 108 7. SUMMARY AND CONCLUSIONS ...................................................................... 109 7.1. Demography of femoral shaft fractures in adults ....................................... 109 7.2. Morphology of femoral shaft fractures in adults ......................................... 109 7.3. Treatment of femoral shaft fractures and nonunions in adults .................... 110 7.4. Prevention of femoral shaft fractures in adults ............................................ 110 ACKNOWLEDGEMENTS ........................................................................................ 113 REFERENCES ........................................................................................................... 115 ORIGINAL PUBLICATIONS .................................................................................... 147 6 ABSTRACT The femur (thigh bone) is the longest, strongest, largest and heaviest tubular bone in the human body, and one of the principal load-bearing bones in the lower extremity. Femoral shaft fractures are among the most common major injuries that an orthopaedic surgeon will be required to treat. Although demographic data of the patients have been analyzed in some epidemiologic studies, little attention has been paid to the characterization of the fracture patterns of femoral shaft fractures using morphologic classification systems. Femoral shaft fractures are commonly thought to be primarily associated with severe trauma in young persons. Low energy violence as a cause of these fractures, especially among the elderly, has been mentioned only sporadically in epidemiologic studies. Anoth- er subgroup of operatively treated femoral shaft fractures are displaced fatigue fractures of the femoral diaphysis, which mainly occur among military trainees. The concept of intramedullary fixation in the treatment of femoral shaft fractures has gained wide acceptance. Delayed union or nonunion following intramedullary nailing of the femur has been considered an infrequent clinical problem. As a consequence of the more frequent use of intramedullary nailing for the treatment of femoral shaft fractures, an increasing number of orthopaedic surgeons will be confronted with this complication. The present study shows that femoral shaft fractures in adults are not exclusively the result of high energy trauma. Low energy trauma can cause 25% of the fractures. Fem- oral shaft fractures caused by low energy violence mainly occur in patients suffering from a chronic disease or a condition causing osteopenia of the femur. In displaced femoral shaft fatigue fractures, regardless of the symptoms, the diagnosis can be delayed