Translation, cross-cultural adaptation, and validation of the Italian version of the Oxford Shoulder Instability Score

Purpose The Oxford Shoulder Instability Score (OSIS) is self-reported outcome measurement developed to evaluate shoulder instability taking into account also adaptive strategies. Valid, reliable, reproducible, and user-friendly translations of outcome measure instruments are needed to allow comparisons of international study results.Methods The Italian translation and cultural adaptation of the OSIS were completed using a Btranslation–back translation^ method and the final version was administered to a sample of 25 consecutive Italian-speaking patients. The psychometric properties of this adaptation were evaluated in terms of feasibility, reliability, construct validity, and responsiveness.Results No major differences occurred between the OSIS translations into Italian and back into English, and no content- or linguistic-related difficulties were reported. The Cronbach’s alpha for the total OSIS was 0.897. Intraclass correlation coefficient value for inter-rater reliability was 0.805, while for intra-rater reliability was 0.586. Spearman rank correla- tion coefficient between the OSIS and the Rowe score was 0.548 (p = 0.005) and between OSIS-I and SF-12 was 0.488 (p = 0.013).Conclusions The Italian version of the OSIS is a reliable, valid, and reproducible outcome measure for clinical evaluation of patients affected by shoulder instability, which remains simple and user-friendly as the original version.