Objective: To investigate the prognostic value of serum hyaluronic acid (HA) and keratan sulfate (KS) levels in relation to tibiofemoral osteoarthritis (OA) of the knee.
Methods: Clinical and demographic data were collected on 94 patients. Radiographs were obtained at study entry and at 5-year followup. Disease progression was defined as 2 mm of joint space narrowing of any tibiofemoral compartment, and/or knee joint surgery during the study period. Serum HA and KS were measured and levels were correlated with entry data and disease progression.
Results: At entry, HA levels were significantly related to disease duration (P = 0.036), minimum joint space (P = 0.049), and previous surgery (P = 0.001). After these variables were taken into account, patients whose disease had progressed were shown to have had significantly higher levels of HA at baseline compared with those whose disease had not progressed (P = 0.019). However, there were no significant differences in levels of serum KS between those with and those without disease progression, at entry (P = 0.779) or at subsequent visits.
Conclusion: These results suggest that serum HA levels predict disease outcome in OA of the knee and confirm that a single measurement of the serum level of KS is not useful as a prognostic marker in OA.