Comparative study of psychometric properties of three assessment tools for degenerative rotator cuff disease

Objective: To compare psychometric properties of Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, Shoulder Pain and Disability Index (SPADI) and Constant-Murley scale, in patients with degenerative rotator cuff disease (DRCD). Design: Longitudinal cohort. Setting: One French university hospital. Methods: The scales were applied twice at one-week interval before physiotherapy and once after physiotherapy two months later. The perceived improvement after treatment was self-assessed on a numerical scale (0-4). The test-retest reliability of the DASH, SPADI and Constant-Murley scales was assessed before treatment by the intraclass correlation coefficient (ICC). The responsiveness was assessed by the paired t-test (P < 0.05) and standardized mean difference (SMD). The correlation between the percentage of variation in scale scores and the self-assessed improvement score after treatment was measured by the Spearman coefficient. Results: Fifty-three patients were included. Twenty-six only were available for reliability. The test-retest reliability was very good for the DASH (ICC = 0.97), SPADI (0.95) and Constant-Murley (0.92). The scale score was improved after treatment for each scale (P < 0.05). The SMD was moderate for the DASH (0.56) and SPADI (0.56) scales, and small for the Constant-Murley (0.44). The correlation between the percentage of variation in scores and self-assessed improvement score after treatment was high, moderate and not significant for the SPADI (0.59, P < 0.0001), DASH (0.42, P < 0.01) and Constant-Murley scales, respectively. Conclusion: The test-retest reliability of the DASH, SPADI and Constant-Murley scales is very good for patients with DRCD. The highest responsiveness was achieved with the SPADI.