Development of a valid Chinese version of the Cumberland Ankle Instability Tool in Chinese-speaking patients with chronic ankle instability disorders

As an effective scale for the condition assessment of patients with chronic ankle instability (CAI), the Cumberland Ankle Instability Tool (CAIT) is the most widely used scale, and its original version is written in English. Therefore, the purpose of our study is to apply the CAIT to Chinese patients and evaluate its responsiveness, reliability, and validity in terms of Chinese patients with CAI. First, we adapted the CAIT into the Chinese edition (CAIT-C), through which cross-cultural adaptation and translation can be carried out in a five-step procedure. Next, recruited patients completed the three periods of the Foot and Ankle Ability Measure (FAAM), CAIT-C, and the Medical Outcomes Study Short-Form 36 (SF-36) scales. Afterward, to assess the responsiveness, reliability, and validity, we calculated the standardized response mean (SRM), effect size (ES), Spearman's correlation coefficient ( r s ), minimal detectable change (MDC), standard error of measurement (SEM), intraclass correlation coefficient (ICC), and Cronbach’s alpha. Generally, in the use of CAI, 131, 119, and 86 patients favorably completed the three periods of the scales. The CAIT-C was proven to have good test–retest reliability (ICC = 0.930) and fine internal consistency (Cronbach’s alpha = 0.845–0.878). The low-value of MDC (0.04–2.28) and SEM (1.73) show it is possible to detect clinical changes when we take advantage of CAIT-C. Good or moderate correlations ( r s = 0.422–0.738) were gained from the physical subscales of the SF-36 and the subscales of the FAAM and the CAIT-C. Fair or poor correlations ( r s = 0.003–0.360) were gained between the mental subscales of the SF-36 and the CAIT-C, which sufficiently indicated that the CAIT-C had good validity. Moreover, good responsiveness was observed in the CAIT-C (ES = 1.316, SRM = 1.418). The CAIT-C scale is an effective, valid, and reliable tool to evaluate Chinese CAI patients.