Compatibility of Biomaterials

Abstract

SUMMARY The advent of total hip replacement has presented new problems in the compatibility of biomaterials. For the first time, as many as three different materials are used in juxtaposition. Compatibility signifies that mutual interactions of the body and the implant cause little if any changes in either one. The stainless steel used for the manufacture of surgical implants in the United States is American Iron and Steel Institute type 316 with low carbon; similar steels are used in other countries. It is suited for such use by virtue of its physical properties, for it is more corrosion resistant in the body than stainless steel. Titanium and its alloys present high corrosion resistance with satisfactory physical properties although with a high coefficient of friction. The tissue reaction is minimal. Polymethylmethacrylate has poor impact strength but, acting as a grouting compound, is capable of holding prostheses in place. The tissue reactions include thermal injury and a reaction to the monomer and polymer that are more marked than that to metals. Ultrahigh molecular weight polyethylene is highly suitable as a bearing surface and in bulk causes a minimal tissue reaction. The long term compatibility of several materials in one prosthesis and to the small particles produced by wear is still unknown.