The most common causes of sudden knee pain include ligament injury, meniscus tear, gout, etc. If the pain persists, patients are advised to seek medical treatment in time. 1. Ligament injury: If the patient has performed strenuous exercise, improper exercise may cause ligament injury or even rupture, which may result in sudden pain in the knee joint, accompanied by symptoms such as joint swelling and impaired mobility. 2. Meniscus Tear: Most of the meniscus tears are caused by external impact or intense bouncing, which may cause pain and activity limitation of the knee joint. 3. Gout: patients suffering from gout, due to the body’s uric acid level is too high for a long time, in the knee can be formed gout stone, gout stone stuck in the knee joint during the activity, or the body’s uric acid level suddenly rise, will cause sudden pain in the knee. The causes of sudden knee pain are many, if the symptoms of knee pain continue without relief, it is recommended to go to the hospital in time to identify the cause of the disease, and then targeted treatment.