The Effect of Clearance in Total Hip Endoprosthesis

The aim of this paper is to establish a theoretical -experimental method which would emphasize the importance of radial clearance between the cotyloid cup and the femoral head in total hip endoprostheses. Three UHMWPE acetabular cups of different diameters, with the same diameter of the femoral head (CoCrMo), were tested on equipment that determines the tribologic parameters of the biomaterials used in total hip endprostheses. The results showed minimum wear for a 0.1-0.15 mm radial clearance and maximum wear at clearance values close to 0, or higher than 0.5 mm.