How to determine whether there is a fracture in the knee collision, mainly from the following three aspects: First, the history of injury, if the patient’s injury history is more serious, such as the occurrence of car cargo, collapse, pressure smash, there is a possibility of fracture. The clinical manifestations of a knee fracture are the following six: 1. swelling of the knee, purple spots, petechiae, and blood in the joint. 2. pain, when pressed, active or even bed does not move, the pain in the knee is severe, most likely fracture. 3. dysfunction, that is, the knee can not walk after the collision, not able to walk down with weight, fracture may have occurred. 4. The fracture site is deformed, there is a depressed deformity in the knee, when you feel the knee is divided into two halves, there is a depression in the middle. 5, squeeze the knee with your hand, up and down collision, you can hear the click-click-click bone scraping sound. 6, abnormal activity, that is, the knee part of the abnormal activities, such as shaking around, the upper part of the knee and the lower part of the knee can not move to one side at the same time. Third, a front and side x-ray of the knee or an additional axial x-ray will be taken to clarify the diagnosis.