Comparison of two hyaluronan drugs in patients with advanced osteoarthritis of the knee. A prospective, randomized, double-blind study with long term follow-up.

OBJECTIVES: To compare the long-term effects of high and low molecular weight hyaluronic acid (HA) applications in severe (Kellgren Lawrence stage III) osteoarthritis (OA) of the knee. METHODS: In a prospective clinical trial 184 knees (92 patients) with radiographic Kellgren Lawrence stage III OA were randomized to receive either 3 intra-articular high molecular weight HA (Hylan G-F 20) injections or 3 low molecular weight HA (Orthovisc) injections at one-week intervals. Patients were evaluated by the Hospital for Special Surgery (HSS) Knee Score and were followed-up for 12 months. RESULTS: The total HSS score in high molecular weight HA patients improved from 71.8+/-11.6 to 86.7+/-11.6 and in low molecular weight HA patients from 66.7+/-11.0 to 86.6+/-9.1 at the end of the trial (p < 0.01). There were no statistically significant differences between the groups and both had improved in all parameters at the latest follow-up (p = 0.000). CONCLUSIONS: Three intra-articular injections at intervals of 1 week of both HA preparations resulted in a pronounced reduction in pain and improved function as measured by the HSS score during a period of 52 weeks, without complications.