CORRELATION BETWEEN SYNOVIAL-FLUID MARKERS OF CARTILAGE AND BONE TURNOVER AND SCINTIGRAPHIC SCAN ABNORMALITIES IN OSTEOARTHRITIS OF THE KNEE

Objective. To test the hypothesis that scintigraphic evidence of bone activity will correlate with biochemical evidence of increased matrix turnover in osteoarthritis (OA). Methods. Keratan sulfate epitope (5D4), chondroitin sulfate epitope (3B3), and osteocalcin (OC) were measured in synovial fluid (SF) from 35 patients with knee OA, within 1 month of bone scan. Results. SF OC levels correlated with 5D4 levels (r = 0.32, P = 0.047) and with abnormalities on scintigraphic scan. Mean OC levels were 47% higher (P = 0.016) in patients with severely abnormal findings on scans compared with levels in patients with mildly abnormal scan findings. No significant association of 5D4 or 3B3 levels and perfusion- or late (bone)-phase scintigraphic abnormalities was found. Conclusion. These data support the hypothesis that there is an association between late-phase bone scan abnormalities and SF biochemical markers of bone turnover in OA.