Hip prothesis: an in vitro wear protocol based on a comparison between gravimetric and profilometric analysis

Ultra high molecular weight polyethylene acetabular cups were analysed by m eans of a shadowgraph method (using a profile projector) to measure linear wear: The results were compared with those of previous wear tests performed on a hip joint simulator Twelve polyethylene acetabular cups were analysed . The specimens were evaluated visually for evidence of polyethylene wear. Ex amination of the polyethylene inner surface did not reveal evidence of surf ace failure such as delamination, fatigue cracks or scratches. Volumetric wear was calculated using a formula based on dimensional change due to the penetration of the femoral head in the acetabular cup. it was fo und to be of the same order of magnitude as the wear obtained in in vitro e xperimental tests.