Do BCP crystals contribute to OsteoArthritis?
Intraarticular BCP crystals are found in up to 60% of patients with OA and are present in cartilage of up to 100% of joints undergoing replacement surgery. Furthermore, their presence correlates with OA severity. Animal studies and in vitro experiments have shown numerous pathways through which BCP crystals may induce OA (including prostaglandin E 2 , interleukin [IL]-1β, tumor necrosis factor α and IL-6). One in vitro study using murine chondrocytes demonstrated that BCP crystals can induce chondrocyte IL-6 expression. Another proposed mechanism involves effects of BCP crystals on osteoclasts and bone remodeling, with in vitro studies demonstrating induction of osteoclastogenesis via RANKL/M-CSF pathways following BCP crystal exposure. The clinical relevance of these findings (do BCP crystals drive disease pathogenesis or represent epiphenomenon of the degenerative process; do BCP crystals potentially identify a subset of patients with OA with more aggressive disease) remains unanswered.
