Viscosupplementation for grade II osteoarthritis of the ankle: a prospective study at 18 months' follow-up.

BACKGROUND: Viscosupplementation, with hyaluronan derivates injected into the intra-space of osteoarthritic joints, is now widely used for the treatment of knee osteoarthritis. This study evaluates the results in terms of pain and disability of intra-articular injections of hyaluronan derivates into the ankle joint in patients suffering from grade II primary or secondary osteoarthritis of the ankle. METHODS: Twenty-one patients with a painful ankle and radiographic evidence of grade II osteoarthritis had three weekly intra-articular injections of 2 ml of hylan G-F 20 (10 mg/ml) into the ankle joint. The primary clinical outcome measurement was the ankle osteoarthritis score (AOS) at the baseline, and at 6, 12 and 18 months. RESULTS: Significant improvement of the AOS from baseline was seen after 6 months (p=0.0001). This improvement was maintained over time with no further changes at 12- and 18-month follow-ups. Regarding pain, the AOS improved over time from the baseline to the 18-month follow up and became statistically significant at the 12- and 18-month follow-ups (p<0.05).