Title:
Chinese version of the Constant-Murley questionnaire for shoulder pain and disability: a reliability and validation study.

Abstract:
Shoulder pain is a common musculoskeletal disorder in Chinese population, which affects more than 1,3 billion individuals. To the best of our knowledge, there has been no available Chinese-language version of measurements of shoulder pain and disability so far. Moreover, the Constant-Murley score (CMS) questionnaire is a universally recognized patient-reported questionnaire for clinical practice and research. The present study was designed to evaluate a Chinese translational version of CMS and subsequently assess its reliability and validity.
The Chinese translational version of CMS was formulated by means of forward-backward translation. Meanwhile, a final review was carried out by an expert committee, followed by conducting a test of the pre-final version. Therefore, the reliability and validity of the Chinese translational version of CMS could be assessed using the internal consistency, construct validity, factor analysis, reliability and floor and ceiling effects. Specifically, the reliability was assessed by testing the internal consistency (Cronbach's α) and test-retest reliability (intraclass coefficient correlation [ICC]), while the construct validity was evaluated via comparison between the Chinese translational version of CMS with visual analog scale (VAS) score and the 36-Item Short Form Health Survey (SF-36, Spearman correlation).
The questionnaire was verified to be acceptable after distribution among 120 subjects with unilateral shoulder pain. Factor analysis had revealed a two-factor and 10-item solution. Moreover, the assessment results indicated that the Chinese translational version of CMS questionnaire harbored good internal consistency (Cronbach's α = 0.739) and test-retest reliability (ICC = 0.827). In addition, the Chinese translational version of CMS was moderately correlated with VAS score (r = 0.497) and SF-36 (r = 0.135). No obvious floor and ceiling effects were observed in the Chinese translational version of CMS questionnaire.
Chinese translational version of CMS exhibited good reliability, which is relatively acceptable and is likely to be widely used in this population.