INTERNAL FIXATION OF HIP FRACTURES – CAUSES OF FAILURE AND OUTCOME OF SALVAGE HIP ARTHROPLASTY

Abstract

Introduction: Failed surgical treatment of hip fractures typically leads to profound functional disability and pain for the individual, technical challenges for the surgical team, and an increase in the financial burden on society. This study had three purposes:

1. to determine the reason/s for failure of internal fixation

2. to record difficulties / complications encountered in converting to a salvage arthroplasty and

3. to compare the outcome of patients who underwent salvage arthroplasty (Group 1) with a matched group of patients who had a primary hip arthroplasty for degenerative disease (Group 2).

Methods: Between 1999 and 2005 41 patients (30 women and 11 men) with a mean age of 70 were treated at our institution with a total hip arthroplasty for failed dynamic hip screw fixation of a fracture of the proximal femur. The radiographs and medical charts of all patients were obtained following institutional approval. The quality of the reduction of the fracture achieved was assessed on the basis of displacement and alignment. Screw position was also assessed. Each patient who had undergone salvage arthroplasty (Group 1) was matched with a patient who had undergone total hip arthroplasty for degenerative disease in our unit (Group 2). Patients were matched for age, sex, implant and time since insertion of the implant. All surviving patients form both groups were followed up for a minimum of two years (mean 5 years). Three main outcome measures were compared between the two groups; surgical complications, the Oxford hip score, and radiographic analysis of the femoral component for signs of loosening

Results: Failure to achieve a good reduction and optimal screw placement was evident in 80% of cases of failed fixation. A high incidence of complications was recorded in the perioperative period during conversion to a salvage arthroplasty. Functional outcome was statistically inferior in Group1, this group also had a much higher incidence of complications. Radiographs at 2 years post operatively showed evidence of femoral stem loosening in 16% of the salvage group compared with 3% in the primary hip arthroplasty group.

Conclusion: When undertaking surgical stabilisation of proximal femoral fractures one should make every effort to achieve the best reduction and most accurate fixation possible. Factors such as osteoporosis, compliance with post-operative mobilisation and delay in fracture fixation are to some extent ‘out of the surgeon’s hands’. Conversion to arthroplasty is technically challenging, and is associated with higher complication rate and poorer outcome than primary hip arthroplasty. We recorded a high incidence of femoral stem loosening in patients who had undergone conversion to hip arthroplasty for failed fixation and would recommend more frequent clinical and radiographic follow up of these patients