RATES OF OSTEOLYSIS IN WELL-FUNCTIONING ALUMINA-ON-HIGHLY CROSS-LINKED POLYETHYLENE BEARING CEMENTLESS THA IN PATIENTS YOUNGER THAN FIFTY WITH FEMORAL HEAD OSTEONECROSIS

Abstract

Background: Alumina ceramic-on-highly cross-linked polyethylene (Al-on-X-linked PE) is attractive because of the potential for reduced wear, osteolysis and loosening of the component. The purpose of this study was to evaluate the clinical and radiographic outcomes of cement-less total hip arthroplasties (THAs) using Al-on-X-linked PE bearing and to determine the rates of osteolysis using radiographs and computer tomographic (CT) scans in young patients with osteonecrosis of femoral head.

Methods: Consecutive primary cementless THAs using Al-on-X-linked PE bearing were performed in 71 patients (73 hips) who were younger than 50 years of age with osteonecrosis of the femoral head. There were 48 men (51 hips) and 23 women (23 hips). The average age at the time of the index arthroplasty was 45.5 years (range, 20 to 50 years). Osteolysis was evaluated using radiographs and CT scanning. The average follow-up was 10.5 years (range, 10 to 13 years).

Results: The mean preoperative Harris hip score was 50.6 points (range, 27 to 55 points), which was improved to 96 points (range, 85 to 100 points) at the final follow-up. Preoperative functional activity was improved significantly (p=0.001) at the latest follow-up. All acetabular and femoral components were fixed by bone ingrown. The mean polyethylene linear penetration was 0.05±0.02 mm per year (range, 0.02 mm to 0.08 mm per year). Radiographic and CT scans demonstrated that no acetabular or femoral osteolysis was detected in any hip at the latest follow-up.

Conclusions: The current generation of anatomic tapered cementless femoral component with Al-on-X-linked PE bearing is functioning well with no osteolysis at a 10-year minimum and average of 10.5-year follow-up in this series of young patients with osteonecrosis of the femoral head.