Effect of protein concentrations of bovine serum albumin and γ-globulin on the frictional response of a cobalt-chromium femoral head.

The study aims to identify the concentration-dependent role of bovine serum albumin (BSA) and γ-globulin in the lubricating ability of a cobalt-chromium femoral head. The frictional coefficients of the cobalt-chromium femoral head decreased with increasing BSA concentrations from 10 to 40 mg/ml and showed statistical differences between any of the BSA concentration groups, except between the 30 and 40 mg/ml concentration groups. In γ-globulin, the frictional coefficients significantly decreased at concentrations of 2.5 and 5.0 mg/ml as compared with the PBS control group, but significant increases were observed at 7.5 and 12.5 mg/ml. These results suggest that the friction of the cobalt-chromium femoral head is dependent on the concentration of both BSA and γ-globulin. However, there is a maximum concentration for BSA to act as an effective boundary lubricant, while the lubricating ability of γ-globulin is most effective in the physiological concentration range within human synovial fluid.