The reliability and validity of the Turkish version of the oxford shoulder instability score

Background: The aim of this study was to adapt the Oxford Shoulder Instability Score to Turkish culture and test its reliability and validity. Methods: This study included 118 patients with shoulder instability. Confirmatory factor analyses, and correlation coefficient between Oxford Shoulder Instability Score and Short Form 36 were calculated in order to test construct validity. Internal consistency was tested using Cronbach's alpha. Pearson correlation were calculated to test reliability. Differential item functioning analysis was performed to detect whether items exhibited differences according to gender. Results: Confirmatory factor analysis indicating the single structure of the Oxford Shoulder Instability Score was confirmed. Cronbach's alpha was calculated as 0.87 for the whole scale. There were positive and strong correlations between the first and follow-up assessments (r = 0.86, p < 0.01). The Turkish version of OSIS showed moderate and significant correlations with domains of the SF-36 in general. Results also showed that there was no item exhibiting differential item functioning analysis in the Turkish version of Oxford Shoulder Instability Score. Conclusion: The Turkish version of the Oxford Shoulder Instability Score is a reliable, valid, reproducible and practical tool. It can be used for patients with shoulder disorders and is recommended for clinical use.