Identification of scratch mechanisms on a retrieved metallic femoral head

Based on the scanning of about 80 areas spread over the entire surface of the retrieved femoral head, hypotheses on the mechanism of scratch generation have been formulated after analysing the observed topographical patterns, the arithmetic mean roughness and the amplitude density function (ADF). The formulated hypotheses have finally been verified comparing the ADF and the bearing area curves of profiles related to the most severely scratched areas with those of simulated worn profiles. This study highlights the major influence of foreign third bodies on the scratching of metallic femoral heads of the Charnley type prostheses.