Wear in conventional and highly cross-linked polyethylene cups: a 5-year follow-up study.

Highly cross-linked polyethylene (XLPE) has been introduced in total hip arthroplasty in an effort to reduce polyethylene wear and the associated periprosthetic osteolysis. Our aim was to demonstrate these reduced wear rates in a 2-dimensional head penetration model and to perform a clinical comparison of both groups using the Harris Hip Score (and SF-36 questionnaire). Sixty hips with a Trilogy XLPE liner (Zimmer) were matched and compared to a control group of 20 conventional Trilogy PE liners (Zimmer). No differences in clinical outcome were seen, but a statistically significant reduction in linear wear was observed in the XLPEgroup, after 5 years. It is clear that, because of the reduction and stabilization of free radicals in polyethylene, a reduction in annual wear can be achieved.