Hip dislocation after modular unipolar hemiarthroplasty.

An institutional review board-approved retrospective review of hip fractures in elderly patients treated with a modular unipolar implant was carried out to identify factors predisposing to dislocation of a hemiarthroplasty. The main outcome measure evaluated was dislocation vs nondislocation. Two hundred seventeen patients underwent the surgery, and 174 were available for review at 6 weeks and 144 at 1 year. The incidence of dislocation was 6%. The average time of dislocation after surgery was 19.3 days. Clinical factors significant for dislocation were male sex and mental disease. Radiographic factors in dislocated hips included a smaller femoral neck and contralateral femoral neck offset. The center edge angle was also smaller in the dislocated patients. These patients had a higher mortality rate.