Abstract
BACKGROUND: Failure of TKA from aseptic loosening is a growing concern, as TKA is performed with increasing frequency. Loosening is multifactorial and may be associated with elevated inflammatory cytokines in addition to biomechanical failure. QUESTIONS/PURPOSES: We asked whether proinflammatory cytokines and chemokines are elevated in synovial fluid from patients undergoing revision surgery as compared to those with osteoarthritis (OA) or rheumatoid arthritis (RA). METHODS: We obtained synovial fluid samples from 20 patients: six with aseptic loosening of TKA (all with bone loss), 10 with primary OA, and four with RA. A panel of cytokines/chemokines was screened using a SearchLight((R)) Array (Pierce Biotechnology, Rockford, IL, USA) in one revision sample. Using these data, we assayed the synovial fluids for monocyte chemotactic protein 1 (MCP-1) by ELISA. RESULTS: We observed an increase in synovial MCP-1 levels in samples from patients planned for TKA revision compared to those with OA or RA. In patients undergoing revision arthroplasty, the mean (+/- SD) MCP-1 concentration was 21,233 +/- 18,966 pg/mL (range, 1550-50,657 pg/mL; n = 6). In patients with OA, the mean MCP-1 level was 3012 +/- 3321 pg/mL. In patients with RA, the mean MCP-1 concentration was 690 +/- 561 pg/mL. CONCLUSIONS: All patients undergoing revision TKA showed elevated concentrations of MCP-1 compared to patients with OA and RA, suggesting MCP-1 may serve as a potential marker or predictor of bone loss in patients undergoing revision surgery. CLINICAL RELEVANCE: MCP-1 may be a novel biomarker in patients showing early symptoms of aseptic loosening of TKA.
