Chronic lateral ankle instability is caused by old injuries to the anterior talofibular ligament and the calcaneofibular ligament, and is mainly characterized by a feeling of instability in the ankle joint, which is prone to recurrent inversion or postrotation sprains, especially on uneven surfaces or when playing sports. Compared with the contralateral side, the laxity of the ankle joint is obviously increased, and MRI examination may show that the ligament is missing, thinned, lax and bent, or thickened due to scarring, hematoma mechanization, and may be combined with articular cartilage injury and impingement syndrome. Conservative treatment mainly consists of muscle strength exercises, such as heel lift, internal and external rotation resistance exercises. Surgical treatment should be considered if conservative treatment fails. Surgical methods include ligament shortening, anterior-superior displacement of the ligament stop, and tendon grafting to reconstruct the ligament.