The medial collateral ligament (MCL) is an important structure on the medial side of the knee that is flattened to prevent knee valgus, and MCL injuries can be classified into 3 degrees based on the valgus test: degree I: no medial palpation with a strong sense of resistance; degree II: medial opening less than 5mm with a good sense of resistance; degree III: medial opening greater than 5mm with soft resistance, or no resistance. In the past, it was thought that the medial collateral ligament has a strong ability to heal itself, and the conservative treatment of acute injury is effective, but acute MCL rupture needs to distinguish different levels and sites as well as the patient’s sports requirements, so different treatment methods need to be selected. degree I injury can all be treated conservatively. degree II or above injury treatment: for example, people with low sports requirements, when the MCL injury is in the upper stop and body, it can be treated conservatively with extension position Fixed for 6 weeks, such as the lower stop point rupture injury, because the lower stop point rupture often turned in the goose foot bursa, resulting in healing difficulties and poor results, so it is recommended that the early surgical lower stop point reconstruction treatment (within 2 weeks after the injury); such as the movement requirements of patients with high, in more than II degree injury recommended surgical treatment, to avoid missing the best time for surgery.