Minimal Clinically Important Differences in ASES and Simple Shoulder Test Scores After Nonoperative Treatment of Rotator Cuff Disease

Background: The minimal clinically important difference is the smallest difference in an outcome score that a patient perceives as beneficial. The purpose of this study was to determine the minimal clinically important difference in the American Shoulder and Elbow Surgeons (ASES) score and in the Simple Shoulder Test (SST) score for patients treated nonoperatively for rotator cuff disease. Methods: Eighty-one patients with tendinitis or a tear of the rotator cuff were treated with nonoperative modalities. Evaluation with the ASES score and the SST was performed at baseline and at a minimum of six weeks after treatment. At the follow-up evaluation, the minimal clinically important difference was estimated for the two scores with use of an anchor-based approach involving fifteen-item (pain and function) and four-item improvement questions. Results: The fifteen-item function and four-item assessments indicated, respectively, that a 2.05-point (p = 0.02) and 2.33-point (p = 0.0009) change in the SST score from baseline represented a minimal clinically important difference. The fifteen-item function, fifteen-item pain, and four-item assessments indicated that a 12.01-point (p = 0.03), 16.92-point (p = 0.004), and 16.72-point (p < 0.0001) change in the ASES score from baseline represented a minimal clinically important difference. Age, sex, initial baseline scores, and hand dominance had no effect on the minimal clinically important differences (p > 0.05). A longer duration of follow-up after treatment was associated with a greater minimal clinically important difference in the ASES score (p < 0.05), although the duration of follow-up had no effect on the minimal clinically important difference in the SST score. Conclusions: Patients with rotator cuff disease who are treated without surgery and have a 2-point change in the SST score or a 12 to 17-point change in the ASES score experience a clinically important change in self-assessed outcome. These minimal clinically important differences can provide the basis for determining if significant differences in outcomes after treatment are clinically relevant.