Knee replacement surgery is divided into five steps as follows: 1. First, a median incision is made in the front of the knee joint, layer by layer. After the patella is turned out, the local ligaments, synovial membrane, osteoid and other related tissues are cleaned up. 2. The osteotomy of the femoral condyle and tibial plateau is performed under the guidance of a template, which means that the surface of the bones at both ends is partially removed. 3. After the osteotomy, the prosthesis is installed at both ends of the knee joint and a trial mold is used to adjust the tightness of the joint. 4. After proper adjustment, the prosthesis is installed at each end. Bone cement is needed to fill and connect between the prosthesis and the bone. 5. After the surgery, the rehabilitation program should be carried out step by step in order to gradually restore the function of the knee joint.