Ankle sprains are one of the most common clinical sports injuries. About 80%-85% of patients can recover well with various conservative treatments. However, 15-20% of patients will become chronically unstable with residual persistent ankle pain and joint instability, and these patients often end up needing surgery. But why is surgery needed? When should you have surgery? What kind of surgery? are unfamiliar to most patients and even to many clinicians. Why is surgery needed for ankle pain? It starts with the symptoms of chronic ankle instability. Patients with chronic ankle instability can have three symptoms: 1. Symptoms remaining after the initial sprain of the ankle joint: this symptom is mostly pain and swelling, which exists at the time of the initial sprain, and is usually caused by the local soft tissue damage at the time of the initial sprain, including posterior lateral ankle pain caused by peroneus longus shortus muscle injury, ankle cartilage injury caused by the ankle cavity of swelling and pain, and the medial pain caused by damage to the deltoid ligament. medial ankle pain due to injury to the deltoid ligament, and lateral ankle pain due to injury to the lateral ankle ligament or anterior talofibular ligament. The damaged tissues not only lead to local pain, but also in the joint will further damage the joint, leading to accelerated wear and tear of other normal tissues in the joint such as cartilage; an often overlooked lesion is, tibiofibular anterior ligament injury and ankle joint instability. 2, ankle ligament tear joint instability symptoms: mainly manifested in recurrent ankle sprains, “ankle weakness” phenomenon and fear when walking on uneven ground or wearing high heels. This instability not only affects the patient’s normal quality of life, but each sprain is a re-injury to the ankle joint, leading to increasing laxity of the ankle joint and secondary injuries to the joint and surrounding tissues. This state of ankle joint instability leads to an increase in the abnormal load on the joint when walking or exercising, which accelerates the degeneration of the joint and increases the likelihood of articular cartilage injuries; an often-overlooked etiology is the ankle joint instability caused by injury to the anterior tibiofibular ligament of the lower tibia, which is also the cause of long-term chronic pain in the ankle joint. 3.Secondary symptoms after repeated sprains of the ankle joint: this symptom is also manifested as pain and swelling in and around the joint, which appears gradually after repeated sprains of the ankle joint, and its cause is the secondary lesions that appear after the instability of the ankle joint. The most common manifestation is chronic synovitis, which means that patients can feel swelling and soreness in the ankle joint after prolonged walking. Secondary cartilage damage within the ankle joint is another major cause of joint pain in chronic ankle instability. Studies have shown that the longer the duration of chronic ankle instability, the more severe the intra-articular cartilage damage is, and that in cases of initial sprains, articular cartilage damage is present in only about 40% of patients.