Procedure 1, anesthesia, position, disinfection, sterile and tourniquet: after successful anesthesia, the patient was placed in a flat position, routinely disinfected with iodine and alcohol, and sterile towel sheet and skin care film were laid. A tourniquet was applied to the right lower extremity to expel blood, and the tourniquet was pressurized to 350 mmHg. 2. Incision: A median incision was made in the right knee, about 25 cm long. The skin, subcutaneous tissue and joint capsule were incised, and the joint capsule and knee extension device were incised along the medial aspect of the patella. 3. Exploration: There was yellowish joint fluid flowing out of the joint, and most of the articular cartilage was worn and destroyed, especially the medial condyle and medial plateau. There was a large amount of osteophytes at the edge of the joint, and the intercondylar fossa was closed, with damage to the cruciate ligament and meniscus. 4.Osteotomy of femoral condyles: drill a hole 0.5 cm above the inner edge of the intercondylar fossa PCL, insert an intramedullary oriented rod, connect the distal femoral cutting die by 5°extrusion, remove the intramedullary rod and perform osteotomy of the distal femur. The distal femur is drilled with a 4° external rotation rotator, and the prosthesis is measured and determined to be No. 7. A four-in-one osteotomy plate was installed, and the femur was osteotomized anteriorly, posteriorly and obliquely, and the skid was shaped. The osteotomy plate was removed and the intercondylarplasty was installed to perform intercondylarplasty. 5.Tibial plateau osteotomy: flex the dislocated knee joint and expose the tibial plateau. The residual meniscus and cruciate ligament are removed. The tibial orientation bar is placed, and the tibial plateau cutting die is installed with a 5° posterior tilt. The depth gauge 2mm contact was placed at the lowest point of the medial plateau, and the resected plateau was approximately 9mm thick, measured as a No. 7 plateau, and the plateau forming plate was installed at the medial 1/3 of the tibial tuberosity to perform tibial medullary styloidoplasty. 6.Installation test: The femoral condyles and 10mm platform pads were installed respectively, and the knee joint was reset and tested for good knee alignment and internal and external rotation stability in the 0° extension and 90° flexion positions, respectively. 7.Patellar molding: patellar molding was performed with the knee flexed, patellar thickness (23-12mm) was measured, the patellar bed thickness of 14mm was retained after molding, the sclerotic part was drilled and a 7/8mm patellar die was installed, and the stability of the knee joint and patellar trajectory were tested again. 8.Installation of prosthesis: Remove the demonstration mold, clean and flush the joint cavity. Mix the bone cement, install the 7# platform, 10mm pad, 7/8mm patella and 7 femoral condyle prosthesis respectively, clean the bone cement, straighten the knee joint and wait for the bone cement to cure. The knee was tested again in 0° of extension and 90° of flexion for good alignment and internal/external rotation stability, 130-0° of joint mobility, and good patellar trajectory. 9. The joint cavity was flushed, a tourniquet was loosened to stop bleeding, and a negative pressure drainage tube was placed in the joint to connect to the negative pressure drainage device. The joint capsule, subcutaneous tissue and skin were sutured layer by layer. A sterile dressing was applied. The left knee was operated in the same manner, with a 7# femoral condyle and a #7/8mm patella prosthesis. After cement curing, the knee joint was tested in 0° of extension and 90° of flexion with good alignment and internal and external rotation stability, 130°-0° of joint mobility, and good patellar trajectory, respectively. The joint cavity was irrigated, a tourniquet was loosened to stop bleeding, and a negative pressure drainage tube was placed in the joint and connected to a negative pressure drainage device. The joint capsule, subcutaneous tissue and skin were sutured layer by layer. Postoperatively, both knees were wrapped with sterile dressings. Both lower limbs were wrapped with elastic bandages. After the operation, the operation went smoothly with intraoperative bleeding of 400 ml. He returned to the ward with a blood pressure of 130/60 mmHg.