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

ABSTRACT

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 "translation-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 correlation 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. LEVEL OF EVIDENCE Prospective cohort study, Level II. CLINICAL RELEVANCE The availability of a validated translation of the OSIS will help surgeon to share their data on shoulder instability diagnostic and treatment in a more reproducible and comparable fashion.