THE “RIM CUTTER” AND ITS EFFECT ON CEMENT PRESSURE AND PENETRATION IN CEMENTED THR.

Abstract

This presentation introduces a new tool to be used in the cementing of acetabular components in total hip arthroplasty, the ‘Rim Cutter’. The Rim Cutter is designed to cut a ledge in the rim of the acetabulum into which a flanged cup can be cemented. The flange is trimmed such that it fits precisely into the ledge cut in the acetabulum. We present the in vitro pilot study of the effect of using this tool on the intra-acetabular cement mantle pressure during cup insertion and also the effect on the depth of cement penetration as the cup is inserted. A significant improvement in both cement pressure and cement penetration over conventional flanged and unflanged cups is noted. Improved cement penetration around the rim of the acetabulum in THR has implications for reducing the rate of aseptic loosening. The pilot study also suggests other beneficial features of using the rim cutter such as improved cup centralisation, control of orientation and the prevention of the cup ‘bottoming out’. Further in vivo studies are required to better assess its efficacy.