Periprosthetic bone loss in total hip arthroplasty: Polyethylene wear debris and the concept of the effective joint space

Abstract

In this study tissue from 34 hips in which there had been prosthetic replacement was analysed to determine the cause of bone resorption. There had either been linear (diffuse) or lytic (localized) areas of periprosthetic bone loss. Specimens from 23 hips were obtained intraoperatively and from 11 hips at autopsy. Tissue analysis demonstrated that macrophages present in the area of bone resorption contained particulate debris. In 34 cases the macrophages contained polyethylene. In 31 cases there were also extracellular particles of polythene. Twenty-two of the 34 hips had intracellular metallic debris and in 10 hips metallic debris was found extracellularly as well. In 10 of the tissue samples from 16 cemented hips polymethylmethacrylate debris was found both intra and extracellularly. Bone resorption was present in cases where tissue analysis demonstrated that macrophages contained polyethylene debris. It was also found that the number of macrophages was related to the degree of bone resorption present. The authors postulated that these results indicate that joint fl uid spreads further than expected even in the case of well fi xed cemented prosthetic components where the fl uid can spread along the bone-prosthetic interface. The authors propose that the effective joint space be thought of as consisting of all periprosthetic regions which joint fl uid and particulate debris can extend to.