New prospects for a prolonged functional life‐span of artificial hip joints by using the material combination polyethylene/aluminium oxide ceramic/metal

Abstract

Investigations over the years have shown that the mirror‐finished Al₂O₃ ceramic is a much more suitable frictional counterpart to ultrahigh molecular weight (UHMW) polyethylene than metal. Despite the extremely great hardness difference between polyethylene and Al₂O₃ ceramic, a considerable lower wear rate is obtained for the polyethylene socket with this new low‐friction material combination. The unexpectedly favorable tribological behavior of this ceramic material in contact with polyethylene may be attributed to the following factors: better values for corrosion resistance characteristics, wettability with liquids, surface gloss, hardness, and scratch resistance of the ceramic material in comparison with those of the hitherto used metallic implant materials (AISI‐316L steel or cast CoCrMo alloy). It appears that, by using this new combination of materials for the socket and the ball, it will be possible to prolong the service life of artificial hip joints considerably without having to effect any fundamental changes in the present design and implantation principle retaining the hitherto used anchorage shaft made of wrought CoNiCrMoTi alloy Protasul‐10 of extremely high corrosion fatigue strength.