Serum keratan sulfate levels in osteoarthritis patients

Serum levels of keratan sulfate (KS), measured by an enzyme‐linked immunosorbent–inhibition assay, were found to be significantly higher in 31 patients with hypertrophic osteoarthritis (OA) than those in 41 adults without joint disease. Seventy‐seven percent of patients with OA, but only 12% of control subjects, had serum levels which were more than 1 SD above the mean of the control group. Following replacement of a single osteoarthritic hip joint, serum KS levels decreased, at first, in all patients. Subsequently, the concentration of serum KS progressively increased; 6 months following surgery, KS levels were similar or close to the preoperative levels in virtually all patients. The results suggest that patients with hypertrophic OA may have a generalized imbalance of cartilage proteoglycan metabolism. Measurements of serum KS are likely to prove most useful in studying this particular subset of patients with generalized OA. Copyright © 1988 American College of Rheumatology