Wear of artificial hip joint material

A non-conforming apparatus was devised to study the wear properties of hip replacement materials (stainless steel femoral head and mainly ultra-high molecular weight polyethylene, UHMWPE). The analysis was by wear depth and various types of microscope examination of the worn surfaces. The importance of proper femoral head surface conditions is emphasized. The dry worn debris matched that retrieved from revision surgery indicating the in vivo wear was without fluid lubrication. A qualitative model is presented to explain the observed wear and wear rate profiles. The long-term wear was within a narrow range that matched in vivo results. Tests on polyetherether ketone (PEEK) polymer indicated that it had superior wear properties to UHMWPE.