Role of polyethylene particles in peri-prosthetic osteolysis: A review

Figure 1 Multi-cellular effects of polyethylene wear particles, following their release from the bearing surface, resulting in osteolysis. Polyethylene (PE) engulfment by monocytes and macrophages, and possibly other cells including fibroblasts, as described in the text, causes their activation and release of pro-inflammatory cytokines, prostaglandins and matrix degrading enzymes. These and other factors promote differentiation of macrophages into bone resorbing osteoclasts. PE effects on osteoblastic lineage cells (osteoblasts, lining cells and potentially osteocytes) following contact with and/or engulfment of particles include promotion of a catabolic phenotype, up-regulation of potent chemotactic agents for osteoclast precursors and osteoclastogenic mediators. The responses in each cell type are indicated by boxed arrows. RANKL:receptor activator of nuclear factor-κB ligand; OPG: osteoprotegerin; M-CSF: macrophage colony stimulating factor; MMPs: Matrix metalloproteinases.