The fibular collateral ligament, also known as the lateral collateral ligament, is an important ligament of the knee joint, and its main function is to maintain the stability of the lateral side of the knee joint and prevent the knee from turning inward. Injury to the fibular collateral ligament can present the following symptoms: First, pain, the pain is more obvious when the knee joint turns inward. Second, swelling, ligament injury can occur around the ligament soft tissue damage or have localized bleeding, which leads to obvious swelling of the injured area. Third, localized bruises and ecchymosis, fibular collateral ligament injury is often accompanied by a small amount of localized bleeding, if the seepage into the subcutaneous can be seen localized obvious bruises and ecchymosis appear. Fourth, activity limitation, the peroneal collateral ligament injury in the knee flexion and extension as well as inversion of the activity is very obvious, especially when the knee joint inversion has obvious activity limitation, the above is the common symptoms of peroneal collateral ligament injury.