Knee arthroplasty is a delicate surgery, a “millimeter” surgery, and in order to obtain good results after the surgery, it is necessary to meet the appropriate standards at each step of the procedure. My surgical style is to not try to be too fast, but to strictly follow the steps step by step, not skipping any steps, checking and verifying that each step is done to the appropriate standard, and if there is a deviation from the standard, immediately fixing the deviation to bring it up to the standard before proceeding to the next step. This ensures correct osteotomy of the knee joint, good balance of the extension and flexion gap and proper soft tissue tension. The advantages of this are good surgical quality, high postoperative patient satisfaction, relatively constant operative time, and no rework. As an example of a common internal derangement of the knee, the surgical steps and criteria achieved in knee arthroplasty are briefly described: incision and visualization, initial removal of the osteophyte, removal of the cruciate ligament and part of the meniscus. Intramedullary positioning of the femur, osteotomy of the distal femur, pre and post osteotomy checking of the osteotomy thickness of the medial and lateral femoral condyles (standard: osteotomy thickness equal to the thickness of the distal femoral prosthesis). Extramedullary positioning to check the femoral force line (standard: point to the center of the femoral head, usually 3-100px medial to the anterior superior iliac spine, note the variation). Perform proximal tibial osteotomy with an appropriate posterior tilt, using the lowest point of the lateral plateau (including the meniscus) as the standard for osteotomy, and check the osteotomy thickness of the lateral plateau (standard: osteotomy thickness equal to the thickness of the thinnest tibial liner). Check the tibial force line (standard: the upper end of the force line bar is aligned with the middle inner 1/3 of the tibial tuberosity and the lower end is aligned with the center of the talus). Measure the tibial plateau type. Again, remove the bony tuberosity, measure the extension gap and medial-lateral balance with a gap measurement block (criteria for extension gap: 1-2 mm medial tension when external rotation stress is applied after placing the gap measurement block and 1-3 mm lateral tension when internal rotation stress is applied. if the extension gap is small, it is achieved by posterior capsule release and adding distal femoral and/or proximal tibial osteotomies. (If medial-lateral balance is not up to standard, medial-lateral soft tissue balance is achieved by soft tissue release). Rotation of the femoral osteotomy template is determined by a combination of reference to the posterior femoral condyle, through condyle line, Whiteside line, and soft tissue tension, and measurement to determine the type of femoral osteotomy template. Place the quadruple osteotomy template, bend the knee at 90° to open the knee gap, measure the flexion gap and medial-lateral balance with a straightedge, and then perform anterior and posterior condylar osteotomy. If the medial-lateral balance of the flexion gap is not equal, the problem can be solved by adjusting the rotation of the osteotomy template, and if the flexion gap is not equal to the extension gap, the problem can be solved by changing the osteotomy template type, moving the template forward or backward. After the anterior and posterior condyles are osteotomized, a plate spreader is placed, the residual medial and lateral menisci are removed, and the posterior femoral condyles are debrided of bone and excess bone. A gap measurement block is placed at 90° of flexion to check the flexion gap and medial-lateral balance (the standard is 1-2 mm of medial tension and 1-3 mm of lateral tension.) If the flexion-extension gap is unbalanced, the extension-extension gap is balanced by osteotomy and release. Then perform anterior and posterior bevel and intercondylar osteotomy. A trial mold is installed and checked for extension (standard: knee fully extended), flexion (standard: gravity method to determine the flexion angle, 130° or more), extension stability (standard: knee very stable in full extension, medial and lateral spread less than 2mm when internal and external rotation stresses are applied; medial spread 1-2mm when external rotation stresses are applied and lateral spread 1-3mm when internal rotation stresses are applied when the knee is flexed 20°) , flexion stability (standard: medial tension 1-2mm when external rotation stress is applied at 90° of knee flexion, lateral tension 1-3mm when internal rotation stress is applied), patellar trajectory (standard: patella is always within the femoral glide groove during flexion and extension. The examination was performed by thumbless test, cloth towel clamp, suture, and loose repellent band. (If the trajectory is not good, the lateral support band is loosened until the patellofemoral trajectory is good). The rotation of the tibial prosthesis is determined and marked using flexion-extension mobility, while referring to the medial 1/3 of the tibial tuberosity (criteria: no gap between the tibial liner and femoral prosthesis during knee extension, and the center of the tibial prosthesis is between the medial edge of the tibial tuberosity and median). The tibial medulla was prepared, flushed, the bone cement fixed the femoral and tibial prostheses, and a trial mold of the liner was placed. After setting of the bone cement, extension, flexion, extension stability, flexion stability and patellar trajectory are checked again and a liner of appropriate thickness is placed. The tourniquet was loosened, hemostasis was achieved, drainage was placed, and the wound was sutured.