TOTAL HIP-REPLACEMENT WITH A TRUNNION BEARING PROSTHESIS - BIOMECHANICAL PRINCIPLES AND PRELIMINARY CLINICAL RESULTS

The biomechanics are presented of a bushing principle forming the basis for a trunnion bearing prosthesis in total hip replacement. the femoral stem is equipped with a trunnion on to which a cylindrical plastic sleeve is applied. On top of this a metal casing is placed which forms the femoral head. On flexion-extension this remains stationary in the acetabular cup and motion occurs between the trunnion and the cylindrical sleeve. Friction between head and cup is reduced to a minimum, decreasing the risk of loosening. A follow-up study of 61 hips replaced by the trunnion bearing prosthesis was performed 2.5 years postoperatively. Eighty-eight per cent were considerably improved. There was one deep infection and two femoral stem loosenings. © 1979 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.