Validity of the Thai version of the Western Ontario shoulder instability index in shoulder instability.

Abstract

Shoulder instability affects quality of life and function. The Western Ontario Shoulder Instability Index (WOSI) is widely used; however, a validated Thai version is not available. This study aimed to translate, culturally adapt, and validate the Thai WOSI. The WOSI was cross-culturally adapted to the Thai version (Thai WOSI) following guidelines. Sixty-two patients comprising 2 women and 60 men, with unilateral shoulder instability, were recruited for this study. All patients completed Thai WOSI and Thai QuickDASH for internal consistency and validity.Additionally, all patients repeated the Thai WOSI two weeks after the initial examination to assess test-retest reproducibility. Sixty-two subjects, with a mean age of 28.76 years (SD, 9.7), were included in the study. Internal consistency (Cronbach's α = 0.956) and test-retest reliability (ICC = 0.97) were excellent. A strong correlation was observed between the Thai WOSI and the Thai QuickDASH (Pearson's r = 0.963), supporting good criterion validity. The results of this study demonstrate that the Thai version of the Western Ontario Shoulder Instability Index (WOSI) is a valid and reliable instrument for assessing shoulder-related function and quality of life in Thai-speaking patients with shoulder instability. Following linguistic translation and cultural adaptation, the Thai WOSI can be confidently used in both clinical practice and research settings to evaluate patients with shoulder instability in the Thai population.