A hip joint simulator study of the performance of metal-on-metal joints: Part I: the role of materials.

The use of metal-on-metal low-wearing bearings has promoted great interest in the factors determining the volume of wear debris generated in such joints, including the developing surface replacement alternatives. Twenty-six pairs of low- and high-carbon components in wrought or cast form of 36 mm nominal diameter and exhibiting similar clearances were studied over 5 million test cycles in a 10-station hip joint simulator. Low-carbon cast materials exhibited higher wear than high-carbon cast or wrought materials. Little difference was found in the running-in wear volumes generated by high-carbon wrought or cast materials, but the wrought material exhibited a slight advantage at the smallest diametral clearance considered of 105 microm. Volumetric wear appeared to decrease as the diametral clearance decreased.