Wear and fracture of the acetabular cup in Charnley low-friction arthroplasty.

Abstract

Seven cases of progressive wear-out and fracture of the cemented high-density polyethylene cup in Charnley low-friction arthroplasty were identified in a group of 1,815 revisions of failed total hip arthroplasties. Normal function, rapid wear in the superolateral direction, and localized superolateral loss of bone-cement interface support with perfect medial cup fixation but, above all, asymptomatic nature of the problem until the moment of sudden failure were the characteristic features. The time to failure ranged from 11 to 20 years. Stem fixation remained unaffected. The findings suggest that the problem was wear-out without any changes that could have been attributed to the volume of high-density wear particles shed into the tissues.