A seven- to 14-year follow-up study of bipolar hip arthroplasty in the treatment of osteonecrosis of the femoral head

Abstract

Bipolar hip arthroplasty (BHA) in the treatment of Ficat stage III osteonecrosis of the femoral head (ONFH) has theoretical advantages over total hip replacement (THR) in that it preserves the natural acetabulum and uses an implant that allows better stability and larger range of movement. The purpose of this study was to evaluate the clinical and radiological outcomes of BHA with uncemented ingrowth stems in the treatment of ONFH. Thirty-nine hips in 34 patients (two women and 32 men) with a mean age at the time of surgery of 45.31 years (range 30-66 years) operated between 1998 and 2005 were examined in a retrospective evaluation. Mean follow-up was 9.5 years (range 3-14 years). Patients were evaluated with the Harris hip score (HHS). Kaplan-Meier survivorship was calculated to examine the revision rate. Radiographic analysis included evaluation of bipolar head migration, radiolucent lines around the stem and osteolysis in the acetabulum and the femur. Evaluation of clinical results revealed an increase in HHS from 28 points preoperatively to 88.6 points at the most recent follow-up. Radiographic evaluation showed bipolar head migration in 3 hips (7.7%). Survival rate of BHA, with revision THR defined as the endpoint, was 92.31% at ten years (CI 95%). All implanted uncemented stems were stable without any radiographic signs of loosening or osteolysis. The results of the present study show that implantation of BHA with uncemented ingrowth stem in Ficat stage III is still justified.