The most common reasons for ACL injury pain are improper treatment, soft tissue adhesion, and re-traumatization. 1. Improper treatment: If the ACL injury or rupture is not treated in time, and the injured part heals poorly, even if it has been a year, pain can still occur, and need to be treated in time. 2. Soft tissue adhesion: after anterior cruciate ligament injury may need to be braked for a period of time, prolonged braking is prone to cause local soft tissue adhesion, which in turn will cause localized pain and activity limitation. 3. Re-traumatization: after ACL injury, traumatization may easily cause ACL injury again, which may lead to knee pain and need to check whether it is accompanied by fracture. Caused by anterior cruciate ligament injury for a year and still have pain for a variety of reasons, if the symptoms continue to have no relief, it is recommended to go to the hospital in a timely manner to find out the cause of the disease, by the doctor targeted treatment.