Long-term effects of alumina components in total hip prostheses.

Six pairs of alumina components of Ceraver-Ostéal total hip prostheses, which were implanted from nine to 12 years, were studied. In the load-bearing areas, the wear takes the form of relief polishing. The depth of wear, after a running-in period, is less than 0.3 microns and then reaches an equilibrium. In four cases, there was no displacement of the sockets and wear tracks were formed on the femoral heads, the sockets being worn on their periphery, never on the apex. In the case of two persons weighing more than 90 kg, two wear tracks were observed on the heads, corresponding to walking and raising from a seated position. In the worst case, the depth of the wear track was 44 microns and the weight of alumina debris was estimated to be 18 mg.