Reduction of the concentration and total amount of keratan sulphate in synovial fluid from patients with osteoarthritis during treatment with piroxicam.

To study the effects of piroxicam on cartilage metabolism in vivo, a three phase (placebo/piroxicam 20 mg/day by mouth/placebo) double blind controlled trial was conducted in patients with osteoarthritis of the knee joint. Twenty one patients were recruited, 19 of whom (11 women, eight men, median age 70 years) completed the treatment schedule. The knee joint under study was aspirated to dryness at four week intervals. Treatment with piroxicam was accompanied by a decrease in the pain score, an improvement in the functional index, and an increased range of movement. Reductions in the concentration (mean (SEM) 120 (6) to 110 (8) micrograms/ml) and the total amount (1.22 (0.34) to 0.99 (0.37) mg) of keratan sulphate, but not the effusion volume (9.4 (2.5) to 8.3 (2.6) ml) were observed during treatment with piroxicam. These findings are consistent with decreased proteoglycan catabolism during treatment with piroxicam. Neither depressed synthesis nor enhanced clearance of degraded proteoglycan fragments can be excluded, however.