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

: This study's objective was to translate and cross-culturally adapt the Cumberland Ankle Instability Tool (CAIT) into the Greek language and to evaluate its psychometric properties.: CAIT was translated and adapted into Greek according to official cross-cultural adaptation guidelines of self-reported measures. The Greek version of the CAIT (CAIT-GR) was tested for reliability (internal consistency, test-retest reliability), validity (discriminative and convergent validity) and floor-ceiling effects. Additionally, a cut-off value discriminating between stable and unstable ankles across healthy participants and participants with ankle complaints was calculated. A convenience sample of 123 Greek individuals was recruited, 43 of which had a history of at least one ankle sprain. All participants completed the final version of the CAIT-GR twice within 7-10 days. Participants with a history of ankle sprain also completed the Greek version of the Lower Extremity Functional Scale (LEFS) and the Visual Analogue Scale (VAS).: CAIT-GR mean scores were 26.9 ± 3.16 for participants without a history of ankle sprain and 20.6 ± 4.62 for the instability group. The cut-off value was at 24.5 points of the total CAIT score (range 0-30). CAIT-GR had a moderate correlation with VAS (0.54) and a high correlation with LEFS (0.735). Results indicated good discriminative validity, high internal consistency (Cronbach's alpha of 0.97) and excellent test-retest reliability (ICC = 0.97, 95%CI = 0.97-0.98). Neither a floor nor a ceiling effect was observed.: The CAIT-GR questionnaire was found to be a reliable and valid measure for chronic ankle instability. It is therefore, available for use in future clinical research and practice.