In order to investigate prosthetic wear, we observed the fine structures of the joint surface consisting of metals or ceramics in several kinds of hip and knee prostheses using a surface profile measuring system and a SEM. The hip prostheses examined were made of Al-ceramics (Kyocera), Zr-ceramics (Kyocera) and Co-Cr alloy (Zimmer). The materials of the knee prostheses were Al-ceramics (Kyocera), Co-Cr alloy (Zimmer) and Ti alloy (Zimmer). None of the prostheses were used clinically.
Surface profile measuring disclosed that surface roughness values of 0.025-0.029μmRa on all the hip prosthesis were less than those of 0.114-0.150μmRa on all the knee prosthesis. In a SEM examination, many streaks running in various directions, probably due to polishing, were observed on the surface of all prostheses. However, the streaks were coarser in all knee prostheses. We conclude that the polishing process should be improved, particularly in knee prostheses.