The Spanish Version of the Constant-Murley Shoulder Score: Translation, Cultural Adaptation, and Validity

Background: The Constant-Murley Score (CMS) is one of the most employed tools for assessing shoulder function. It was first devised in 1987 for the English population and is now widely used internationally. However, it had yet to be cross-culturally adapted and vali-dated to Spanish, which is the world's second-most native language. Formal adaptation and validation of clinical scores is paramount for them to be used with rigorous scientific methodology. Methods: Following international recommendations for the cross-cultural adaptation of self-report measures, the CMS was first adapted into Spanish in six stages: translation, synthesis, back-translation, a review by expert committee, pretesting, and final appraisal by expert committee. After conducting a pretest with 30 individuals, the Spanish version of the CMS was tested on 104 patients with various shoulder pathologies to assess content, construct, criterion validity, and reliability.Results: No major conflicts were encountered in the process of cross-cultural adaptation, with 96.7% of pretested patients having a full understanding of every item in the test. The validation showed excellent content validity (content validity index = .90), construct val-idity (strong correlation between items within the same subsection of the test), and criterion validity (CMS -Simple Shoulder Test, Pearson r = .587, P = .01; CMS -American Shoulder and Elbow Surgeons, Pearson r = .690, P = .01). Reliability of the test was also excellent, with high internal consistency (Cronbach's a = .819), interrater reliability (intraclass correlation coefficient = .982), and intrarater reliability (intraclass correlation coefficient = .937), without showing ceiling or floor effects.Conclusion: Spanish version of the CMS has been proved to accurately reproduce the original score and to be easily comprehensible by native Spanish speakers with acceptable intrarater-interrater reliability and construct validity.