The causes of knee pain are different depending on the location, such as pain in the front of the knee joint, the medial and lateral space of the knee joint, and the back of the knee joint, as follows: First, pain in the front of the knee joint on pressure: most of them are prepatellar bursitis and patellar fracture, and the patient will have local pain, swelling, and limited knee movement, if it is a patellar fracture, X-ray can confirm the diagnosis; second, pain in the medial and lateral space of the knee joint Pain on pressure: most of them are osteoarthritis of the knee and meniscal injury of the knee, the patient will have pain in the knee joint, especially when weight-bearing. There will be significant pain and sometimes swelling on the back of the knee joint with pressure, and MRI will reveal joint effusion and synovial hyperplasia.