The Future of the Polyethylene Cup

Abstract

Fixation of the Charnley cups has proved reliable in our patients with the longest follow-ups of 12–14 years. It is most unusual to see loosening of late onset. When it has occurred, the fixation of the cup was already unsatisfactory on roentgenograms for a long time. This confirms Charnley’s own experience and that of those who have used his prosthesis for many years. Ten years ago, one would hardly have dared to hope for such good results. This leads us to think that this type of fixation will continue much longer, as there is no reason why such a stable, unchanging, mechanical situation should suddenly change after 15 years. At the present time, methylmethacrylate cement (together with a small head) provides the best guarantee, both of a good initial result and of a fixation that will be long lasting. The durability of the fixation of the cup does not seem to be a problem for the immediate future.