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.