The responsiveness and validity of the Rotator Cuff Quality of Life (RC-QOL) index in a 2-year follow-up study

Background: The Rotator Cuff Quality of Life (RC-QOL) index was developed to evaluate quality of life in patients with rotator cuff disease. This study provides additional psychometric testing in accordance with the Consensus-Based Standards for the Selection of Health Measurement Instruments guidelines. Methods: This was a 2-year follow-up study on 66 patients (mean age, 59 ± 10 years) originally presenting with chronic full-thickness rotator cuff tears to a tertiary care center. The methodology involved testing internal consistency, content validity, and criterion validity. Responsiveness was evaluated using 3 strategies: 1) standardized response mean of the raw change scores; 2) Guyatt’s Responsiveness Index; and 3) Global Rating Scales of improvement correlated to a quality of life measure. Results: Content validity was confirmed with a Cronbach α of 0.92 (95% confidence interval, 0.92-0.95) and absence of floor and ceiling effects. Criterion validity was confirmed using the Western Ontario Rotator Cuff Index as a reference standard (r = 0.87, P