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

It is shown in this work that lubricant sorption in ultrahigh molecular wei ght polyethylene (UHMWPE) increases with available surface area of the comp onent. This has clinical relevance, because sliding and articulation experi enced in simulator studies can result in changes in surface roughness and t he creation of new surfaces. This study compares the fluid sorption of orth opedic grade UHMWPE with different surface areas (but equivalent volume) fo r different sterilization methods. For both the gamma radiation and nonster ile control samples, the gain in total fluid absorbed scaled proportionatel y with surface area. For the EtO sterilization treatment, the fluid gain wa s nonlinear and substantially less than the radiated and control groups. Th e findings from this study clearly indicate that the sterilization and surf ace area affect the fluid uptake and weight gain of UHMWPE. (C) 2000 John W iley & Sons, Inc.