Abstract
Information acquired from retrieved polyethylene ace-tabular components is invaluable to the design engineer in achieving better in-vivo service. The failure criteria used, namely mode-1 to 4 wear, are vague and not user-friendly. Based on an in-depth evaluation of over 100 failed acetabular cups, this study investigated a more precise classification
Although all the cups were obtained from one centre, they were not clearly marked, making an accurate assessment of the in-vivo life impossible. This, however, was not the aim of the study. We used visual inspections, magnifying glasses, colour-dye penetrant and stereo-microscopes to examine the cups. The most common defects identified were mechanical damage, cracks in the material, plastic flow, scratches, fretting, flaking and wear particles embedded in base material. These cups provided valuable data for compilation of a proposed set of failure criteria to be used in future. Visible defects should be used as a classification tool in future cup-failure analysis. They are explicit and can be used with confidence.
The abstracts were prepared by Professor M.B.E. Sweet. Correspondence should be addressed to him at PO Box 47363, Parklands, Johannesburg 2121, South Africa.
