Presence of silicon in massive osteolysis after cementless total hip arthroplasty: Case report

Abstract

Osteolysis associated with artificial joint arthroplasty seems to be the result of particles of wear debris (from ultra-high molecular weight polyethylene (UHMWPE), polymethylmethacrylate (PMMA), and metals), causing a macrophage response. Silicon particles, as residual contaminants embedded in the surface of both textured metal implants and polyethylene sockets, may be a factor in osteolysis. We present the case of a 57-year-old woman who had massive and aggressive osteolysis. The osteolytic lesion was isolated in the greater trochanter region 5 years after she had had primary cementless total hip arthroplasty (Cobalt-chromium alloy). There were no signs of mechanical loosening, but she experienced moderate pain. Under a polarized microscope and scanning electron micrography, a biopsied specimen from the osteolytic lesion revealed conglomerates of UHMWPE particles of various sizes between proliferated synovium-like cells. Quantitative energy-dispersive X-ray analysis focused on the conglomerates of UHMWPE particles demonstrated a marked presence of silicon. Although the definitive causative factor for a 1he osteolysis was regarded as a foreign-body reaction induced by UHMWPE particles, the presence of silicon was interesting in terms of the pathogenesis of osteolysis associated with artificial joint surgery.