Temperature behavior of sliding portions in the wear test of artificial joint materials using a joint simulator and its influence

Abstract

The purpose of this study was to investigate the temperature behavior of sliding portions in the wear test of artificial joint materials using a hip joint simulator. We measured the concentrations of total protein in the lubricating liquids to determine whether they had an influence on the temperature of the fluids. Fluorescence microscopy was used to examine the relationship between the temperature of the sliding portions and the adsorbed state of the proteins. The results showed that the temperature of the sliding portions increased to more than 41°C during the running-in period, and it remained constant between 40 to 41°C after this period. However, it was necessary to exchange the lubricating liquids at regular time intervals to maintain the temperature of the sliding portions during prolonged wear tests. The exchange of lubricating liquids helped to maintain the concentration of total protein in lubricating liquids; however, the aggregate of the proteins increased at a temperature more than 40°C at the sliding surfaces. Consequently, it was considered that the adsorption of agglomerated proteins caused by the increased temperature of the sliding portions might influence the wear mechanism of artificial joints.