Increased serum C-reactive protein levels by immunonephelometry in patients with rapidly destructive hip osteoarthritis

To compare serum C-reactive protein levels measured using a highly sensitive immunonephelometry method in patients with rapidly destructive versus slowly progressive hip osteoarthritis.Ten patients meeting criteria for rapidly destructive hip osteoarthritis were compared to 25 patients with slowly progressive hip osteoarthritis defined as less than 0.20 mm joint space loss over the last year. Serum C-reactive protein was assayed using an immunonephelometry method with a detection threshold of 0.17 mg/L and a coefficient of variation of less than 5%.One patient in each group was excluded because of a C-reactive protein level greater than 15 mg/L. The mean C-reactive protein level in the remaining 33 patients was 3.05 +/- 3.46 mg/L (range, 0.10-14.9 mg/L). Mean C-reactive protein was significantly higher in the rapidly destructive group than in the slowly progressive group (5.61 +/- 4.75 versus 1.94 +/- 1.98 mg/L, P = 0.01), even after adjustment for potential confounding factors.Our data suggest that rapidly destructive hip osteoarthritis may be associated with some degree of inflammation reflected by a small but significant increase in serum C-reactive protein levels.