Fluid-sorption phenomena in sterilized polyethylene acetabular prostheses.
The weight changes due to fluid-sorption were measured in 62 radiation-sterilized acetabular sockets and 10 unsterilized discs. The materials included two types of ultra-high molecular weight (UHMW) polyethylene (RCH 1000; Hi-Fax 1900) and a carbon-fibre-reinforced polyethylene (CFPE). The fluid absorption curve was consistently biphasic. In the first 30 d soak-period (Phase 1), the initial rate of fluid absorption averaged 153 micrograms/d for conventional UHMW polyethylene and 278 micrograms/d for carbon-fibre-reinforced polyethylene. In Phase 2, beyond 30 d and up to 400 d, fluid absorption reduced to linear rates of 27 micrograms/d for UHMW polyethylene and 43 micrograms/d for CFPE. The latter soak-weight-gain values corresponded to only 0.00016%/d and 0.00034%/d respectively. There was little difference in absorption rates between sterilized and unsterilized samples. However soak rates were generally higher in water compared to serum.
D000042:Absorption; D002244:Carbon / Q000592:standards; D000077482:Carbon Fiber; D006622:Hip Prosthesis; D006801:Humans; D008970:Molecular Weight; D010969:Plastics / Q000592:standards; D011095:Polyethylenes / Q000592:standards*; D013242:Sterilization; D013314:Stress, Mechanical
D000077482:Carbon Fiber; D010969:Plastics; D011095:Polyethylenes; C037808:plastic, carbon fiber reinforced; D002244:Carbon