Cross-cultural adaptation and validation of the Spanish version of the Cumberland Ankle Instability Tool (CAIT): an instrument to assess unilateral chronic ankle instability

The Cumberland Ankle Instability Tool (CAIT) is a valid instrument to determine the presence of chronic ankle instability (CAI) and to assess its severity. Self-report test is very useful for researchers and clinical practice, and CAI is a widespread tool. Nevertheless, there is lack of measurement instruments validated into Spanish, which represents a major difficulty for research dealing with a Spanish-speaking population. The questionnaire was cross-culturally adapted into Spanish. The psychometric properties tested in the Spanish version of the CAIT were measured for internal consistency, test–retest reliability, construct validity, criterion validity, and responsiveness in 108 participants who were recruited from several fitness centers. The Spanish version of the CAIT had high internal consistency (Cronbach's α = 0.766) and reliability (intraclass correlation coefficient = 0.979, 95 % confidence interval (CI) = 0.958–0.990). Correlation with the 36-item Short-Form Health Survey (SF-36) physical component summary score (rho = 0.241, p = 0.012) was greater than the SF-36 mental component summary score (rho = −0.162, p = 0.094). The construct validity shows three different factors in the questionnaire and good responsiveness with a mean change of −2.43 (95 % CI = −3.12 to 1.73, p < 0.0001) and a size effect of Cohen's d = 1.07. The Spanish version of the CAIT has been shown to be a valid and reliable instrument for measuring chronic ankle instability and constitutes a useful instrument for the measurement of CAI in the clinical setting in Spain.