Long-term bilateral THA study finds no osteolysis with ceramic or HXLPE bearings in patients under 65Two hip implant materials show similar long-term results in younger patients after 25 years

BACKGROUND: We determined the long-term (≥ 20 years) clinical outcomes of metaphyseal-fitting anatomic cementless implants with alumina ceramic-on-ceramic (C-O-C) or alumina ceramic-on-highly cross-linked polyethylene (C-O-HXLPE) bearings. METHODS: Consecutive primary total hip arthroplasty (THA) procedures were performed in 250 patients (500 hips; 140 men, 110 women) aged < 65 years. This is a series of bilateral THA patients who were randomized to receive a C-O-C bearing on one side and a C-O-HXLPE on the contralateral side. The mean age at the time of THA was 45 years (range, 31 to 65), with a mean follow-up of 25.5 years (range, 20 to 30). Osteolysis was assessed using radiographs and computed tomography scans, whereas polyethylene wear was measured using a computer software program. RESULTS: There was no hip in either group that had osteolysis. The mean polyethylene penetration rate of the HXLPE liner was 0.041 ± 0.005 mm/year. The survival rate in the C-O-C bearing group was 96.8% (95% confidence interval [CI], 92 to 100) for the femoral component and 97.2% (95% CI, 92 to 100) for the acetabular component at a mean of 25.5 years of follow-up. In the C-O-HXLPE bearing group, the survival rate for both femoral and acetabular components was 97.6% (95% CI, 92 to 100) at a mean of 25.5 years of follow-up. The clinical and functional results (Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index score, and University of California, Los Angeles, activity score) improved significantly (P < 0.05) at the final follow-up in both groups. CONCLUSIONS: At a mean follow-up of 25.5 years, a metaphyseal-fitting anatomic cementless femoral stem with alumina C-O-C or alumina C-O-HXLPE bearings demonstrated excellent long-term function, with no osteolysis and no ceramic femoral head or acetabular liner fractures.