Background: Ankle arthritis can cause substantial pain and functional limitation. Previous studies have indicated that five weekly intra-articular injections of hyaluronate were safe and effective in the treatment of ankle osteoarthritis. The purpose of this study was to evaluate the effect and safety of three weekly injections of hyaluronate in patients with unilateral ankle arthritis.

Methods: Fifty patients who had had unilateral ankle pain for at least six months and were classified radiographically as having Kellgren-Lawrence grade-2 or 3 ankle arthritis were recruited for a prospective study. Patients received three weekly intra-articular injections of hyaluronate. The primary outcome was the change in the Ankle Osteoarthritis Scale score at six months after the third injection. Secondary outcomes included the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score, four clinical tests of balance, consumption of rescue analgesics, and global patient satisfaction.

Results: Forty-six participants completed the study. A significant reduction in the mean Ankle Osteoarthritis Scale score was noted at one, three, and six months after the third injection (p < 0.05 for each follow-up visit compared with baseline). The mean AOFAS Ankle-Hindfoot Score improved from 60.5 points at baseline to 73.5, 75.5, and 76.7 points at one, three, and six months of follow-up, respectively (p < 0.05). The patients demonstrated significant improvement on all four balance tests at each follow-up visit (p < 0.05 for each test compared with baseline). Acetaminophen consumption dropped significantly following treatment (p < 0.05). The patients' satisfaction rate was high, and no serious adverse events were reported.

Conclusions: This study suggests that three weekly injections of hyaluronate are well-tolerated and can provide pain relief and improve function and balance in patients with unilateral ankle arthritis. Larger controlled trials with longer follow-up are necessary to verify the effects of hyaluronate in the treatment of ankle arthritis.