WEAR MECHANISMS FOR ULTRAHIGH MOLECULAR-WEIGHT POLYETHYLENE IN THE TOTAL HIP PROSTHESIS

Ultrahigh molecular weight polyethylene is now extensively used in total joint replacements, and there is ample clinical evidence that this material wears at a significant rate in such applications. Six commercially available total hip replacements were subjected to an accurate simulation of clinical mechanical and chemical conditions, and the wear behavior of the polyethylene components was analyzed by friction coefficient measurements and scanning electron micrography of the wear surfaces. The results indicate that all of the proposed wear mechanisms excepting adhesive and abrasive wear may be eliminated. It is highly likely that abrasion fatigue and related phenomena are central to the wear process in many prostheses, but the wear process may be ultimately determined in many cases by the type of defects present in the manufactured material. Copyright © 1979 John Wiley & Sons, Inc.