The role of elastoviscosity in the efficacy of viscosupplementation for osteoarthritis of the knee: a comparison of hylan G-F 20 and a lower-molecular-weight hyaluronan.

The objective of this 12-week, double-masked, randomized, multicenter study was to compare the elastoviscous properties of a high-molecular-weight viscosupplement, hylan G-F 20 (polymer concentration, 0.8%), with those of a lower-molecular-weight hyaluronan (LMW HA) product (polymer concentration, 1%) and to determine the relationship of elastoviscosity to efficacy in the treatment of patients with osteoarthritis (OA) of the knee. Patients had radiographically confirmed primary idiopathic OA of the knee (Larsen grades I to V) with pain despite other treatments. After a 2-week washout period, 70 patients (73 knees) received three 2-mL intra-articular injections of test solution at 1-week intervals. Thirty-eight patients (38 knees) received hylan G-F 20, and 32 patients (35 knees) received LMW HA. During the 12-week follow-up period, the primary outcome measures assessed by patients (using a visual analogue scale) were weight-bearing pain, most painful knee movement, and overall treatment response; the primary outcome measures assessed by study evaluators were weight-bearing pain and overall assessment of treatment. The dynamic elastoviscous properties of the test solutions were measured on an oscillating Couette-type rheometer. Hylan G-F 20 was more elastoviscous than the LMW HA at all frequencies measured (0.001 to 10 Hz). At the final evaluation, patients who received hylan G-F 20 had significantly better results on all primary outcome measures compared with those who received LMW HA. No systemic adverse events were reported. Local adverse events consisted of pain or swelling, noted in 2 of 38 knees injected with hylan G-F 20, and pain, noted in 1 of 35 knees injected with LMW HA (adverse event rates per injection, 1.8% and 0.9%, respectively). The difference in the incidence of adverse events between groups was not statistically significant. The higher-molecular-weight, more elastoviscous hylan G-F 20 had significantly greater pain-relieving effects than did the lower-molecular-weight, less elastoviscous hyaluronan.

Viscosupplementation with hylan G-F 20: a 26-week controlled trial of efficacy and safety in the osteoarthritic knee.

Hylan G-F 20, which is derived from hyaluronan, is a highly purified, elastoviscous fluid with rheologic properties similar to those of synovial fluid in the knee joints of healthy young persons. The efficacy and safety of viscosupplementation with hylan G-F 20 were evaluated in a multicenter, double-masked clinical study in patients with chronic idiopathic osteoarthritis (OA) of the knee of 1 to 30 years' duration. Three intra-articular injections of 2 mL hylan G-F 20 were administered 1 week apart to 57 knees. The control group (60 knees) received 2 mL of physiologic buffered saline solution at the same intervals. Patients were predominantly female (65%), with a mean age of 62 years and mean weight of 76 kg. Using a visual analogue scale, patients assessed the following clinical variables: pain during weight-bearing, pain at rest during the night, reduction of pain during the most painful movement of the knee, and treatment success. Evaluators also assessed patients' loss of activity while performing difficult daily tasks and treatment success. There was dramatic early improvement in all six variables with hylan G-F 20 beginning after the first injection; the improvement continued through the study end points. The differences between hylan G-F 20 and saline treatment were statistically significant for all outcome measures. In the hylan G-F 20 group, 39% to 56% of patients were free or nearly free of weight-bearing pain 10 to 24 weeks after the last injection. Treatment with saline was less effective, with fewer than 13% of patients free or nearly free of weight-bearing pain. Use of rescue therapy was significantly greater in the saline group than in the hylan G-F 20 group. No adverse events were observed in the injected joint after hylan G-F 20 treatment. These results demonstrate that hylan G-F 20 is effective and well tolerated in the management of chronic idiopathic OA.