HISTOLOGIC ANALYSIS OF THE PERIPROSTHETIC TISSUES OF LONG-TERM SURVIVING CEMENTED TOTAL HIP ARTHROPLASTIES

Qualitative and semiquantitative features of the interfacial membranes of five long-term (>16 years) surviving cemented total hip arthroplas ties (four revision cases and one autopsy case) were compared with tho se of thirty short-term surviving (<15 years) cemented hip prostheses. Cement granulomas, micron-sized polyethylene particles-induced giant- celled granulomas, sheets of submicron-sized polyethylene particles-la den macrophages, and aggregated, metallic particles-laden macrophages were scattered in the fibrous tissue of all interfacial membranes. Qua ntitatively, characteristics of the interfacial membranes of the two g roups differed from one another. The dominant species of prosthetic de bris in the interfacial membranes of the short-term surviving joint re placements was derived from the polyethylene acetabular socket, and, c orrespondingly, giant-celled granulomas and macrophagic sheets predomi nated. Metallic particles and the macrophagic reaction thereto dominat ed in the interfacial membranes of the long-term surviving arthroplast ies, and large cement and polyethylene chunks typically were incorpora ted in the fibrous tissue of the membranes without an accompanying mac rophagic response. In long-term surviving hip arthroplasties, metallic particles may be at least as important as polymeric detritus in stimu lating the formation of the bone-resorbing, granulomatous interfacial membrane, which is the hallmark of aseptically loosened arthroplasties . Differences in mechanical settings may account for unlike modes and rates of generation of prosthetic breakdown products, explaining the d isparate survivorship of different patients' artificial joints.