title: Reliability and validity of the Western Ontario Shoulder Instability Index (WOSI) in the Japanese population.
abstract: 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Orthopaedic Surgery, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Hatta
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Shinozaki
authors.forename: Rei
authors.initials: R
authors.lastname: Omi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sano
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Akira
authors.initials: A
authors.lastname: Ando
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugaya
authors.forename: Toshitake
authors.initials: T
authors.lastname: Aizawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Kuriyama
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
mesh_terms: D044466:Asian People; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis*; D015203:Reproducibility of Results; D012785:Shoulder Joint; D011795:Surveys and Questionnaires; D014177:Translations