The Cumberland Ankle Instability Tool (CAIT) in the Dutch population with and without complaints of ankle instability

PURPOSE: To develop a translated Dutch version of the Cumberland Ankle Instability Tool (CAIT) and test its psychometric properties in a Dutch population with foot and ankle complaints. METHODS: The CAIT was translated into the Dutch language using a forward–backward translation design. Of the 130 subsequent patients visiting the outpatient clinic for foot and ankle complaints who were asked to fill out a questionnaire containing the CAIT, the Foot and Ankle Outcome Score (FAOS), and the numeric rating scale (NRS) pain, 98 completed the questionnaire. After a 1-week period, patients were asked to fill out a second questionnaire online containing the CAIT and NRS pain. This second questionnaire was completed by 70 patients. With these data, the construct validity, test–retest reliability, internal consistency, measurement error, and ceiling and floor effects were assessed. Additionally, a cut-off value to discriminate between stable and unstable ankles, in patients with ankle complaints, was calculated. RESULTS: Construct validity showed moderate correlations between the CAIT and FAOS subscales (Spearman’s correlation coefficient (SCC) = 0.36–0.43), and the NRS pain (SCC = −0.55). The cut-off value was found at 11.5 points of the total CAIT score (range 0–30). Test–retest reliability showed to be excellent with an intraclass correlation coefficient of 0.94. Internal consistency was high (Cronbach’s α = 0.86). No ceiling or floor effects were detected. CONCLUSION: Based on the results, the Dutch version of the CAIT is a valid and reliable questionnaire to assess ankle instability in the Dutch population and is able to differentiate between a functionally unstable and stable ankle. The tool is the first suitable tool to objectify the severity of ankle instability specific complaints and assess change in the Dutch population. Level of evidence II.