Cross-cultural adaptation and validation of the Chinese version of the ankle joint functional assessment tool (AJFAT) questionnaire.

Background: Ankle joint functional assessment tool (AJFAT) is gradually becoming a popular tool for diagnosing functional ankle instability (FAI). However, due to the lack of standard Chinese versions of AJFAT and reliability and validity tests, the use of AJFAT in the Chinese population is limited. This study aimed to translate and cross-culturally adapt the AJFAT from English into Chinese, and evaluate the reliability and validity of the Chinese version of AJFAT and to investigate its psychometric properties.

Methods: The translation and cross-cultural adaptation of AJFAT was performed according to guidelines for cross-cultural adaptation of self-report measures. 126 participants with a history of ankle sprain completed the AJFAT-C twice within 14 days and completed the Cumberland ankle instability tool (CAIT-C) once. Test-retest reliability, internal consistency, ceiling and floor effects, convergent and structure validity and discriminative ability were investigated.

Results: The test-retest reliability (ICC = 0.91, 95%CI = 0.87-0.94) and internal consistency (Cronbach's alpha = 0.87) of the AJFAT-C were excellent. No ceiling or floor effects were detected. A moderate correlation between the AJFAT-C and the CAIT-C suggested a moderate convergent validity. The AJFAT-C had a two-factor structure: 1. function of the unstable side of the ankle joint (9 items) and 2. symptoms of the unstable side of the ankle (2 items). The ideal cut-off point of the AJFAT-C was calculated as 26 points.

Conclusion: The Chinese version of AJFAT can be considered as a valid and reliable ankle joint function evaluation tool that can be applied in clinical and research work.