Victorian Institute of Sport Assessment-Achilles (VISA-A) Questionnaire-Minimal Clinically Important Difference for Active People With Midportion Achilles Tendinopathy: A Prospective Cohort Study

OBJECTIVE: To determine the minimal clinically important difference (MCID) for the Victorian Institute of Sport Assessment-Achilles (VISA-A) score in patients with midportion Achilles tendinopathy (AT). DESIGN: Prospective cohort study. METHODS: We included physically active patients with midportion AT who received exercises and an injection. We measured the VISA-A score (ranging from 0 to 100 points, where 100 points represents a healthy tendon) at baseline and at 12 weeks and 24 weeks after treatment, and the 7-point Global Assessment Scale (ranging from "worse than ever" to "completely recovered") at 12 weeks and 24 weeks after treatment. We dichotomized the Global Assessment Scale to not improved ("worse than ever" to "unchanged") or improved ("moderately improved" to "completely recovered"). The area under the curve and the Youden's index value closest to 1 were determined for both MCIDs (12 and 24 weeks), with corresponding sensitivity and specificity. RESULTS: Sixty-four patients were included, and 61 patients (95%) completed the 24-week follow-up. The MCID was 14 points (95% confidence interval [CI]: 3, 19) over a 12-week period, corresponding to 57% sensitivity and 88% specificity. The MCID was 7 points (95% CI: -10, 28) over a 24-week period, with 85% sensitivity and 62% specificity. CONCLUSION: A change in VISA-A score of at least 14 points after 12 weeks or at least 7 points after 24 weeks of exercise therapy and an injection reflects a meaningful change for physically active patients with midportion AT.