The German Short Musculoskeletal Function Assessment questionnaire:: reliability, validity, responsiveness, and comparison with the Short Form 36 and Constant score -: a prospective evaluation of patients undergoing repair for rotator cuff tear

In a prospective clinical trial, first the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D) was tested for reliability, validity, and responsiveness in 23 patients with rotator cuff tears, and secondly the Short Form (SF)-36, and the Constant score were evaluated comparatively in 45 patients with rotator cuff tear undergoing open repair. Retest reliability was excellent for the functional index of the SMFA-D and satisfactory for the bother index. The SMFA-D showed good validity and responsiveness. All three instruments demonstrated significantly the positive effect of rotator cuff repair at 12-month follow-up. Using comparable scales, effect sizes were bigger with the SMFA-D than with the SF-36 and as big as the Constant score. Significant correlations of the SMFA-D indices with the SF-36 scales and the Constant score could be shown preoperatively. At 12-month follow-up, all correlations between SMFA-D indices, SF-36 scales, and Constant score function scales were still significant. We recommend use of the SMFA-D to assess changes in functional status concerning patients with rotator cuff tear undergoing open repair.