Fluid sorption of orthopedic grade ultrahigh molecular weight polyethylene in a serum environment is affected by the surface area and sterilization method.

It is shown in this work that lubricant sorption in ultrahigh molecular weight polyethylene (UHMWPE) increases with available surface area of the component. This has clinical relevance, because sliding and articulation experienced in simulator studies can result in changes in surface roughness and the creation of new surfaces. This study compares the fluid sorption of orthopedic grade UHMWPE with different surface areas (but equivalent volume) for different sterilization methods. For both the gamma radiation and nonsterile control samples, the gain in total fluid absorbed scaled proportionately with surface area. For the EtO sterilization treatment, the fluid gain was nonlinear and substantially less than the radiated and control groups. The findings from this study clearly indicate that the sterilization and surface area affect the fluid uptake and weight gain of UHMWPE.