THR Osteolysis Wheeless

Description: Wheeless Textbook of Orthopaedics Discussion: - most common complication in total hip arthroplasty and most common cause of component failure; - osteolysis is a time dependent process which arises from inflammatory reaction against polyethylene particulate debris; - patho-biology: - osteolysis is mediated primary by macrophages (fibroblasts and endothelial cells also play a role); - these cells are activated by wear debris (primarily polyethylene, but also metal and polymethylmethacrylate debris); - chemical mediators include: interleukin-1 (bone-resorbing cytokine) and tumor necrosis factor; - in the report by Yanming Bi et al (JBJS 2001), the authors present study showed that titanium particles induced both murine marrow cells and human peripheral blood monocytes to produce factors that stimulated osteoclast differentiation; - mean increase in osteoclast differentiation was 29.3 ± 9.4-fold. - they showed that titanium particles stimulate in vitro bone resorption primarily by inducing osteoclast differentiation;