Treatment of osteoarthritis of the ankle by intra-articular injections of hyaluronic acid: a prospective study.

BACKGROUND: Treatment of osteoarthritis of the ankle is similar to that of any other large joint and includes conservative and surgical options. Surgical treatment in severe cases is fusion or joint replacement, whereas conservative treatment is limited and includes mainly ankle supports and physiotherapy. Hyaluronic acid was discovered by Meyer and Palmer in 1934 and has recently been widely used in the treatment of knee osteoarthritis. We evaluated the efficacy of an intra-articular preparation containing sodium hyaluronate in the treatment of osteoarthritis of the ankle.

METHODS: We studied 16 patients aged 31 to 79 years (mean age, 43 years) with symptomatic ankle osteoarthritis of 9 months' to 27 years' duration. The radiographic severity of the ankle osteoarthritis was graded II, III, or IV according to Kellgren and Lawrence. Arthritic ankles underwent intra-articular injections of 25 mg of sodium hyaluronate for 5 consecutive weeks. Follow-up visits were performed 4, 8, 11, 17, and 32 weeks after treatment and included clinical evaluation and objective scoring.

RESULTS: Global assessment showed improvement in 13 of 15 patients who completed the study. There was improvement by 20% in range of motion and a significant reduction in pain assessed by visual analog scale and ankle-hindfoot scores, all statistically significant. Seven months after treatment, no decrease in efficacy was shown. Two patients did not show any significant improvement in global assessment after treatment. One patient was dropped from follow-up owing to concurrent back surgery.

CONCLUSIONS: Symptomatic relief of signs and symptoms of osteoarthritis of the ankle was achieved by injection of an intra-articular preparation containing sodium hyaluronate. There were significant improvements, in objective and subjective parameters, that lasted for more than 7 months. Ankle intra-articular injection of sodium hyaluronate is a valid conservative treatment for ankle osteoarthritis.