Intra-articular injections of hyaluronic acid in osteoarthritis of the subtalar joint: a pilot study.

We evaluated the efficacy of intra-articular viscosupplementation with sodium hyaluronate in the management of osteoarthritis of the subtalar joint. A total of 22 patients, aged 22 to 72 years (mean 53), with symptomatic subtalar joint osteoarthritis of 1 to 20 years' duration (mean 4.2) and a severity of Kellgren-Lawrence grade II to IV and Paley and Hall grade 1 to 3, were entered into the present study. Intra-articular injections of 10 mg sodium hyaluronate (Euflexxa) were administered weekly to the subtalar joint for 3 weeks. Clinical evaluations and objective scoring using the American Orthopaedic Foot and Ankle Society Ankle Hindfoot score, visual analog scale, maximum walking distance, pain frequency, and subjective global function were performed at baseline and 4, 12, and 28 weeks after treatment. Significant improvement occurred in the American Orthopaedic Foot and Ankle Society Ankle Hindfoot scores (baseline score 54.5, week 28 score 73.7; p < .01) and visual analog scale assessment (baseline pain, stiffness, and function score 5.4, 5.8, and 6.9; week 28 pain, stiffness, and function score 2.8, 3.1, and 3.8, respectively; p < .01). Global assessment showed improvement in 18 of 20 patients completing the study (p < .01). The tolerated walking distance significantly improved from 770 ± 886 m to 2,075 ± 1,500 m (p < .001). Improvement lasted for more than 6 months. Intra-articular injection of sodium hyaluronate should be considered in the conservative management of subtalar osteoarthritis.