LESSONS LEARNED FROM IMPLANT RETRIEVAL OF CERAMIC BEARINGS: A CASE STUDY

摘要

Polycrystalline ceramics have been considered highly suited to eliminate the problems of polyethylene particle induced osteolysis. The alumina ceramic satisfies two of the most important criteria for total joint replacements (THR): they are extremely wear resistant and highly biocompatible. Although some older generations of alumina ceramic bearings had problems associated with poor manufacturing, modern generation alumina ceramics are made using much improved techniques. However, ceramic bearings are not without some risk because of the brittle nature of the material combined with their extreme rigidity and hardness. The world literature is full of clinical and retrieval articles on worn UHMWPE cups. However there is much less known about the effects of cup design, range of motion, and impingement risks with ceramic cups. Implant retrieval analysis combines the examination of the removed implants, measurements of wear and histopathology of the periprosthetic tissues. This combination can provide useful information about the in vivo performance of an implant. A case study of a 17-year Mittelmeier total hip is presented here as an example of what can be learned by implant retrieval analysis of ceramic bearing total hips.