Reliability and Validity of the Korean Version of Foot and Ankle Disability Index

The Foot and Ankle Disability Index (FADI) is one of the most commonly used tools for evaluating foot and ankle function. Due to the lack of a Korean version for properly evaluating Koreans, it was not possible to compare Korean data with data from other countries using FADI. Therefore, we created a Korean version of the FADI questionnaire and evaluated its reliability and validity. We translated the English version of FADI and FADI-sport into Korean and then back into English. The Korean version of the FADI and FADI-sport, the previously verified visual analog scale (VAS) score, and the previously validated Medical Outcomes Study Short-Form 36-item questionnaire (SF-36) were administered to outpatients with chronic foot and ankle pain. A total of 64 patients who visited the outpatient clinic for chronic foot and ankle pain from January 2023 to March 2023 were included. To evaluate test-retest reliability and internal consistency, we used the intraclass correlation coefficient and Cronbach's alpha, respectively. We also assessed the concurrent and construct validity of the Korean version of FADI and FADI-sport by comparing them with the VAS and SF-36. Cronbach's alpha values were 0.953 and 0.945 for the FADI and FADI-sport, respectively, indicating good internal consistency. The reproducibility was good, and a strong correlation was observed between FADI, VAS, and SF-36. Therefore, the validation of the Korean version of the FADI was successfully performed, and it is a reliable questionnaire for self-evaluation of a patient's foot and ankle condition.