Background: The Western Ontario Shoulder Instability Index (WOSI) questionnaire is a disease-specific self-evaluated measurement tool used for patients with shoulder instability. The purpose of this study was to evaluate the reliability and validity of the WOSI Japanese version for the Japanese population. Methods: The WOSI Japanese version was prepared by use of several steps including translation, back translation, and verification by the author and owner of the WOSI. Reliability (internal consistency and reproducibility) and validity were then tested for 85 patients with shoulder instability. All patients completed the WOSI Japanese version, Quick DASH, and SF-36, and underwent assessment of the Rowe rating scale for the purpose of internal consistency and validity. Fifty-nine of the patients repeated the WOSI 2 weeks after the first examination for assessment of test-retest reproducibility. Results: Both internal consistency (0.84 for Cronbach's alpha) and reproducibility (Pearson's r = 0.91, intraclass correlation coefficient = 0.91) indicated the reliability of the WOSI Japanese questionnaire was good. Comparison with the Rowe rating scale (p < 0.001) also showed validity was good. The correlation coefficient between the WOSI Japanese version and the Quick DASH (Pearson's r = 0.62) was higher than that between the WOSI Japanese version and the SF-36 (Pearson's r = 0.10-0.36 for subscales). Conclusion: The WOSI Japanese questionnaire is a reliable self-assessment tool that is comparable with the original English version. We therefore recommend use of the WOSI Japanese version when evaluating patients with shoulder instability in the Japanese population.
ASJC Scopus subject areas
- Orthopedics and Sports Medicine