S ORIGINAL ARTICLE The development and validation of a questionnaire for rotator cuff disorders: The Functional Shoulder Score

Background: The purpose of the present study was to validate the Functional Shoulder Score (FSS), a new patient-reported outcome score specifically designed to evaluate patients with rotator cuff disorders. Methods: One hundred and nineteen patients were assessed using two shoulder scoring systems [the FSS and the Constant–Murley Score (CMS)] at 3 weeks pre- and 6 months post-arthroscopic rotator cuff surgery. The reliability, validity, responsiveness and interpretability of the FSS were evaluated. Results: Reliability analysis (test–retest) showed an intraclass correlation coefficient value of 0.96 [95 % confidence interval (CI) 0.92 to 0.98]. Internal consistency analysis revealed a Cronbach’s alpha coefficient of 0.93. The Pearson correlation coefficient FSS-CMS was 0.782 pre-operatively and 0.737 postoperatively (p< 0.0005). There was a statis-tically significant increase in FSS scores postoperatively, an effect size of 3.06 and standardized response mean of 2.80. The value for minimal detectable change was 8.38 scale points (based on a 90 % CI) and the minimal clinically important difference for improvement was 24.7 5.4 points. Conclusions: The FSS is a patient-reported outcome measure that can easily be incorporated into clinical practice, providing a quick, reliable, valid and practical measure for rotator cuff problems. The questionnaire is highly sensitive to clinical change