Ankle sprains are very common in sports injuries, the most common of which is posterior rotation injury of the ankle, i.e., lateral collateral ligament injury of the ankle, including anterior talofibular ligament, heel-fibular ligament and posterior talofibular ligament injury. The so-called posterior rotation injury is, in fact, a combined action, including internal rotation of the ankle, inversion of the heel talofibular joint and inversion of the forefoot, which is difficult to separate completely during the injury process. In sports, for some reason the body loses its center of gravity, or steps on someone else’s foot when jumping up and landing, or the foot is stepped on and tripped during sports, etc. may produce the action of posterior rotation of the foot, causing the lateral ligament injury of the ankle. Most patients, because there is no fracture after ankle sprain, neglect the treatment of lateral collateral ligament injury of the ankle, resulting in repeated ankle sprains and joint instability, also called habitual ankle subluxation. What are the manifestations after lateral collateral ankle ligament injury? The possibility of a lateral collateral ligament injury should be considered if the patient has a significant history of posterior ankle rotation injury with pain on the lateral aspect of the injured ankle, most noticeable when walking and moving the joint. If the injury is not iced and pressure bandaged promptly, localized swelling rapidly develops on the lateral aspect of the ankle and extends to the front of the ankle joint. Two or three days after the injury, the bruising and bruising on the lateral aspect of the ankle is most obvious. On examination, the pressure points were mainly in the area where the anterior talofibular ligament and the heel-fibular ligament were located. Secondly, the lateral pain increased when the foot was passively rotated back. A positive drawer test was considered a complete rupture of the lateral collateral ligament. A positive inversion test indicates a complete rupture of the anterior talofibular ligament or/and the heel-fibular ligament. x-rays can reveal any avulsion fracture of the lateral ankle tip, and inversion stress position x-rays can reveal any widening of the lateral ankle point. MRI is diagnostically important for the extent of ligament rupture. ”Do I need treatment for a sprained foot but no fracture? The goal of treatment for a torn lateral collateral ankle ligament is to return the patient to pre-injury level of motion as soon as possible and to the greatest extent possible. For freshly torn lateral collateral ankle ligaments, non-surgical treatment can be used for mild to moderate tears, but they should be more securely fixed in a cast and replaced with a walking cast or walking boot after 1 to 2 weeks, followed by the use of an ankle brace for 3 weeks for better results. For cases with severe torn ligament injury, significant joint instability, or combined fracture, and old ankle instability, surgical treatment is required. The torn ligament severed ends should be surgically sutured together; ligament stop reconstruction should be performed when the ligament is avulsed from the stop and direct suturing is difficult. When cartilage or osteochondral injury is suspected in the joint, arthroscopic exploration should be performed to repair the cartilage lesion and remove the joint free body. Postoperative plaster fixation should be performed for 3 weeks, and rehabilitation training such as joint mobility, muscle strength and proprioception should be started early.