Chronic Ankle Instability Research and Cross-Cultural Adapta-tion Process Necessity for the Self-Reported Questionnaire

Chronic Ankle Instability (CAI) is characterized by various symptoms such as the sensation of “giving way,” pain, weakness, loss of function, and reduced range of motion (ROM) of the ankle (1). The symptoms of CAI can be classified into me-chanical ankle instability (MAI), functional ankle instability (FAI), and perceived instability (PI) (1). In order to assess this subjective measure, a pa-tient-reported outcome (PRO) questionnaire, also known as a self-reported outcome questionnaire, is recommended and applying the PRO question-naire with specific cut-off scores is essential for re-turn-to-play decision making when dealing with a lateral ankle sprain and PI (2). The International Ankle Consortium (IAC) also strongly recom-mended using PRO questionnaires such as the Cumberland Ankle Instability Tool (CAIT) in or-der to diagnose CAI (3, 4).