Influence of Synovial Fluid Constituents on the Wear of Cobalt-Chromium-Molybdenum Alloy for Metal-on-Metal Joint Prostheses

Abstract

The wear behavior of a cobalt-chromium-molybdenum alloy sliding against itself under a mixed or boundary lubricating condition was studied in pin-on-plate reciprocating tests with respect to metal-on-metal joint prostheses. Phospholipid L-α DPPC (dipalmitoyl phosphatidylcholine) and proteins (mixture of albumin and γ-globulin) ordinarily reduced the wear rate. However, the wear rate of the pin bearing surface which was rubbed on the same contact zone was increased by the proteins. These two contrasting results were explained by the difference in the role of the adsorbed film of proteins on the bearing surface, which served as either a protective layer to reduce wear or a blockade layer to increase wear.