Objective: To evaluate the validity and reliability of the Brazilian Portuguese version of the Western Ontario Rotator Cuff Index (WORC).
Design and setting: A cross-sectional survey at the Physiotherapy Unit and Outpatient Orthopedic and Traumatology Clinic, Universidade Federal de São Paulo.
Methods: To test validity, 100 patients with rotator cuff disorders were evaluated using the WORC, clinically relevant outcomes for patients with shoulder disorders (pain, range of motion, and strength), and the Disabilities of Arm, Shoulder, and Hand (DASH), University of California Los Angeles Shoulder Rating Scale (UCLA), and Short Form-36 (SF-36) self-report measures. The WORC was repeated on 50 patients on the same day (more than 1 hour later) and after a mean interval of 7 days to evaluate the test-retest reliability. Concurrent validity was tested by correlating the WORC to the other outcome measures using Pearson's correlation coefficient. Test-retest reliability and internal consistency were determined by the intraclass correlation coefficient and Cronbach's alpha coefficient, respectively. The scores were used to assess the standard error measurement (SEM) and minimal detectable change (MDC).
Results: Analysis between the WORC and clinically relevant outcomes for patients with shoulder disorders revealed weak to strong correlations; the weakest for active internal rotation (r = -0.22) and the strongest for pain during movement (r = -0.75). Strong correlations were found among the WORC and the DASH and UCLA (r = -0.86 and r = 0.80, respectively). There were moderate correlations between the WORC and SF-36 domains (0.37 to 0.69); the best correlations related to the physical domains. Reliability analysis revealed excellent results, with the intraclass correlation coefficient ranging from 0.95 to 0.99 and Cronbach's alpha ranging from 0.88 to 0.97. The SEM was 5.2 and 3.0 for time 0 and after a mean interval of 7 days, respectively. The MDC was 7.1 over this mean time interval (90% confidence interval).
Conclusions: The Brazilian version of the WORC proved to be a valid and reliable measurement tool for assessing health-related quality of life in patients with rotator cuff diseases.