Prognostic Factors after Intra-Articular Hyaluronic Acid Injection in Ankle Osteoarthritis

PURPOSE: The goal of this study was to identify baseline prognostic factors of outcome in ankle osteoarthritis patients after intra-articular hyaluronic acid injection. MATERIALS AND METHODS: Patients with ankle osteoarthritis who received hyaluronic acid injection therapy were retrospectively reviewed. Each patient received weekly intra-articular hyaluronic acid injections (2 mL) for 3 weeks. Six predictors including gender, age, symptom duration, radiographic osteoarthritis stage, radiographic subchondral cyst, and fracture history were evaluated. Visual analogue scale (VAS) and patient satisfaction were evaluated as outcome measures. These predictors and outcome measurements were included in a logistic regression model for statistical analysis. RESULTS: Total of 40 consecutive patients (21 male, 19 female) were included in this study. Mean age was 60.6. Average follow up period was 13 months. The mean VAS recorded 3, 6, and 12 months after the first injection was 3.6 (SD 2.54, p<0.001), 4.33 (SD 2.9, p<0.001), and 5.3 (SD 2.7, p=0.0071), respectively, when compared to baseline VAS. Early stage disease was identified as an independent predictor associated with 'positive VAS outcome' at 3 and 6 months. Early stage disease and duration of pain less than 1 year were independent predictors associated with higher satisfaction. CONCLUSION: While hyaluronic acid injection for ankle osteoarthritis is a safe and effective treatment, careful selection of patients should be made according to the above prognostic predictors.