WEAR BEHAVIOR AND HISTOPATHOLOGY OF CLASSIC CEMENTED METAL ON METAL HIP ENDOPROSTHESES

The authors reviewed their collection of retrieved all metal hip joint s (9 McKee-Farrar, 7 Muller, and 3 Huggler type prostheses) and tissue s from the joint capsules and implant beds. The amount of wear was mea sured, and the total volume was calculated, The tissues were analyzed by atomic absorption spectral analysis or inductively coupled plasma m ass spectrometry and examined by light and scanning electron microscop y. The size of particles was measured with a texture analysis system, The articulating surfaces showed many delicate scratches which represe nt normal wear, The calculated annual wear averaged approximately 5 mm (3) per year, which is low compared with polyethylene. The cellular re action to metal wear particles was regarded as mild, The cellular reac tion to scattered and worn bone cement was always more pronounced than to metallic debris, Scanning electron microscopy confirmed the irregu lar shapes and mostly submicron size of the metal particles. The analy tically detected metal content of the periarticular tissue was relativ ely low and in accordance with the wear measurements from the articula ting surfaces, The excess of chromium in the tissues is discussed in t he light of the elimination of cobalt as well as the relation between elements representing either corrosion products or elements still boun d in wear particles.