[Wear measurements of hip prostheses with UHMW polyethylene (RCH-1000) socket and chromium plated protasul-10 head (author's transl)].

An estimation of wear was carried out on 100 of 340 UHMW polyethylene sockets (RCH 1000) that were implanted with Protasul-10 prostheses furnished with a chromium plated head. This was effected by measuring the position of the head relative to the socket as seen on radiographs during a follow-up period of 4 years. The method employed was verified in 3 cases (in which the socket had been removed) by measurements on silastic casts of the bearing surface. Practically no difference in the results was observed. The average wear rate amounted to 0.16 mm/year over an observation period of 4 years. Furthermore, it has been observed that para-articular calcification seems to be independent of the amount of abrasive debris present. It seems rather to depend on other factors, such as the size of the haematom, degree of muscle necrosis, etc.