Abstract
Metal-on-metal joint prosthesis considered consists of a cobalt-chrome acetabular insert, articulating against a cobalt-chromium femoral head. The two bearing surfaces have possibility of direct contact with each other in the friction process. The metallic oxide film that forms on the bearing surface has a large effect on the wear characteristics. The oxide film damaged by the friction process, we have shown that a decrease of the oxygen supply in a lubricant does not always increase the wear. The idea of 'coverage of the bearing surfaces' is introduced in order to elucidate the mechanism. This ' coverage' will control re-formation of oxide film on the bearing surface. The purpose of this study is to investigate the effect of 'coverage' on the wear of a cobalt-chrome bearing surface.
