Cross cultural adaptation, reliability and validity of the Polish version of the Cumberland Ankle Instability Tool.

The aim of this study was to develop a Polish version of the Cumberland Ankle Instability Tool (CAIT-PL) questionnaire and perform CAIT-PL cultural adaptation with assessment of its psychometric properties. The original CAIT was translated into the Polish language using standard guidelines. The CAIT-PL was completed on 2 occasions by 105 participants both with and without a history of ankle sprains. Psychometric evaluation of CAIT-PL included an assessment of internal consistency, test-retest reliability, standard error of measurement, convergent and construct validity. The CAIT-PL was successfully translated and adapted into Polish culture with satisfactory internal consistency (Cronbach's α = 0.83) and adequate test-retest reliability resulting in ICC = 0.89 (95% CI: 0.84-0.92). Measurement error was low (SEM = 0.76 and MDC = 2.10). Convergent validity of the CAIT-PL ranged from weak to strong using Spearman's correlation coefficient between CAIT-PL and FAOS subscales ( = 0.39-0.67;  < 0.05). Construct validity was confirmed. The Polish version of the Cumberland Ankle Instability Tool is a valid and reliable questionnaire for assessment of functional ankle instability among the Polish population.