Management pitfalls of fractured neck of femur in osteogenesis imperfecta.

INTRODUCTION: Fractured neck of femur in osteogenesis imperfecta is rarely reported. Its management is always difficult because of bone fragility and the outcome is not well known. We, therefore, aimed to study the management pitfalls in this group of patients.

METHODS: We retrospectively reviewed five cases of fractured neck of femur in four patients treated in our hospital between 2006 and 2009. The demographic data, mode of injury, fracture configuration, treatment, complications, clinical and radiological outcome were reviewed.

RESULTS: According to the Sillence classification, one patient was type I, two were type III and one was type IV. There were two children (aged 8 and 15 years) and two adults (aged 21 and 22 years), with the 8 year-old girl suffering from hip fracture on different sides in two accidents. All five hip fractures were the result of low-energy injury and were associated with other fractures. Two undisplaced fractures required intra-operative fluoroscopic confirmation to demonstrate movement at the fracture site. The interval between the injury and fixation ranged from 6 h to 3 days. One hip required secondary surgery to openly reduce the fracture due to inadequate primary fixation and reduction. Two hips were fixed with paediatric dynamic hip screws and three hips were fixed with cannulated screws. All patients were immobilised in hip spica for 6 weeks. The average follow-up was 4 years (3-5 years). All patients had satisfactory union and none of them developed radiological evidence of avascular necrosis at the latest follow-up. All patients returned to their pre-injury functional level.

CONCLUSION: Fractured neck of femur is rare given the high prevalence of long bone fractures in osteogenesis imperfecta. They all have characteristic associated fractures of the extremity at the time of injury and neck of femur fractures could be easily missed. Fracture fixation is a great challenge to the orthopaedic surgeons because of the small size of the patients, poor bone quality with suboptimal imaging intra-operatively and compromised purchase of fixation devices. The choice of implants should be determined by the size of the patients and the presence of prior instrumentation close to the hip joint.