The Birmingham hip resurfacing prosthesis: an independent single surgeon's experience at 7-year follow-up.

An independent single surgeon's 7-year experience with Birmingham hip resurfacing is presented. The study also involved investigation of the significance of pedestal sign in patients requiring revision. A consecutive 117 hips in 101 patients (59 male and 42 female patients) operated on by the senior author (VGJ) were assessed at a mean follow-up of 7 years (range, 5-9.4 years). Mean age at surgery was 54 years (range, 20-74 years). Seventy-three hips had a preoperative diagnosis of primary osteoarthritis, and secondary osteoarthritis was seen in 44 hips. Failure was defined as revision for any reason. Revision of the femoral component alone was undertaken in 8 hips (6.8%): 5 within first year for periprosthetic fracture neck of femur and in 3 hips after 5 years of follow-up. In 2 patients who were known to have osteonecrosis of the femoral head preoperatively, the femoral component progressively collapsed into varus after 5 years of follow-up. Pedestal sign was the earliest radiologic sign noted in these 2 patients and progressed rapidly within 1 year on serial radiographs well before the onset of clinical symptoms. Kaplan-Meier survival with revision as end point at 7 years was 91.5% (95% confidence interval, 97.6%-85.4%).