Wear of medical grade silicone rubber against titanium and ultrahigh molecular weight polyethylene

Abstract

The replacement of arthritic small joints, such as the fingers and wrist, has typically involved the use of one-piece silicone rubber implants. Newer designs have involved the silicone moving against either a titanium or ultrahigh molecular weight polyethylene (UHMWPE) component. The aim of this study was to investigate the wear of medical grade silicone rubber against titanium and UHMWPE. A pin-on-disc apparatus was used to slide a titanium and UHMWPE pin against a silicone disc, in the presence of either a Ringer's solution or bovine serum lubricant. Testing was undertaken at a sliding speed of 0.079 m/s and was continued for 10 km. Wear factors for titanium against silicone were 40.0 x 10(-6) mm(3)/N m and 66.5 x 10(-6) mm(3)/N m for bovine serum and Ringer's solution, respectively. The wear factors for UHMWPE against silicone were higher with values of 84.4 x 10(-6) mm(3)/N m and 88.3 x 10(-6) mm(3)/N m for bovine serum and Ringer's solution, respectively. The results of this study will be useful in future designs of finger and wrist implants that combine silicone rubber with either titanium or UHMWPE.