Fluid absorption study in ultra-high molecular weight polyethylene (UHMWPE) sterilized and unsterilized acetabular cups

Abstract

The weight gain due to fluid absorption was measured in γ-sterilized, ethylene oxide (ETO) gas-sterilized, and unsterilized ultra-high molecular weight (UHMW) polyethylene acetabular cups. After about 2 months the total average fluid absorption gain of the polyethylene cups was: 1.76 ± 0.45 mg (average ± standard deviation) for the unsterilized polyethylene cups, 2.81 ± 0.95 mg for the γ-sterilized polyethylene cups and 1.51 ± 0.34 for the ETO gas-sterilized polyethylene cups. There was little difference in fluid absorption between the sterilized and unsterilized specimens. In particular, the γ-sterilized acetabular cups absorbed more than the ETO gas-sterilized and the unsterilized cups. However, the weight gain was higher in serum compared with that in water.