Torn knee ligaments are judged in the following ways: 1. there are obvious symptoms of painful swelling of the knee joint with limited range of motion. 2. there is strenuous movement of the knee joint prior to these symptoms, especially during the movement of a knee sprain, which is more likely to result in damage to the ligament. 3. the physician has an internal and external knee stress test (+) as well as an anterior and posterior drawer test (+) in addition to the swelling and painful condition during the examination. ), because it is difficult to get these tests completed with painful symptoms.4. An MRI of the knee is required to show edema at the site of the torn ligament or a break in the continuity of the ligament. The above four conditions can basically clarify whether there is a ligament tear or the severity of the entire ligament tear injury, and on top of that, can directly determine the appropriate treatment after the ligament tear, whether surgical ligament reconstruction is needed or whether conservative treatment is performed.