Objective: To compare the efficacy of single 6-ml intraarticular injection between hylan G-F 20 and hyaluronic acid (HA) for knee osteoarthritis.

Material and method: Thirty-two patients with primary knee arthritis, who were randomly received single intraarticular injection of 6-ml hylan G-F 20 (Synvisc) or HA (Hyalgan), were prospectively evaluated for clinical outcomes at a minimum 26-week follow-up. The parameters, including visual analog scale (VAS) during walking, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Short-Form 36 (SF-36) questionnaires, were evaluated at pre-injection, then at 1 week, 4 weeks, 8 weeks, 12 weeks and 26 weeks, post-injection.

Results: There were 15 patients in both groups who were available for final follow-up with no statistical differences in demographic data, VAS during walking, WOMAC score and SF-36 score at pre-injection. There was no adverse event related to viscosupplementation using in is better than of both agents. At 26-week follow-up, patients in both groups had significantly improved VAS during walking (p < 0.01), WOMAC score (p < 0.01) and SF-36 (p < 0.05) with no statistical differences between groups. However the cost of hylan G-F 20 was much more expensive than that of HA (534 USD vs. 252 USD).

Conclusion: A single intraarticular injection of both hylan G-F 20 and HA for primary knee arthritis had no adverse event related to 6-ml volume. At 26-week follow-up of the present preliminary study, both groups had similarly improved clinical outcomes post-injection. Further study in larger population is required. As the cost of hylan G-F 20 was 2 times higher than HA, a single 6-ml intraarticular injection of HA (Hyalgan) provided better cost-effectiveness than hylan G-F 20 (Synvisc).