The Danish version of the modified Constant-Murley shoulder score: reliability, agreement, and construct validity

Test-retest study. Objectives To assess the reliability, agreement, and validity of the Danish version of the modified Constant-Murley score (CMS). Modified CMS guidelines were published in 2008. These modifications have recently been translated and cross-culturally adapted into a Danish version. However, the reliability and the validity of this version have yet to be established. A total of 45 patients with shoulder impingement syndrome were examined by 2 raters using the modified version of the CMS and a questionnaire that included the Oxford shoulder score. Both raters had a minimum of experience using the CMS. Intrarater and interrater agreement and reliability were examined and compared. Construct validity was assessed by the correlation between the scores of the CMS and the Oxford shoulder score. The minimal detectable change was estimated to be 13 and 11 points for raters A and B, respectively. The intraclass correlation coefficient was 0.93 for rater A and 0.95 for rater B. Interrater comparison demonstrated a minimal detectable change of 12 points and an intraclass correlation coefficient of 0.94. The correlation coefficient between the CMS and the Oxford shoulder score was 0.76. The intrarater and interrater reliability and agreement of the Danish version of the modified CMS were found to be acceptable, and construct validity was confirmed.