Knee replacement surgery has now become an effective and proven treatment method for severe knee disorders. Severe knee disorders such as severe osteoarthritis, rheumatoid arthritis, or various types of traumatic arthritis often cause pain and seriously affect the quality of daily life of the patient. Different surgical approaches have their advantages and disadvantages when it comes to intraoperative knee joint exposure to facilitate smooth surgery. Next, we introduce a procedure that is less traumatic to the tissues, has faster postoperative functional recovery, and has a significantly faster recovery than the traditional surgical approach, allowing patients to quickly return to their preoperative state of life. MIS small-incision knee replacement surgery differs from conventional knee replacement in that the MIS small-incision knee replacement surgery incision is about 10 cm, while the conventional knee replacement surgery incision is about 20 cm. The patella is turned. MIS small-incision knee replacement surgery requires a high level of skill from the surgeon. During surgery, the knee joint must be exposed by flexion and extension of the knee joint, making full use of the mobile window, and pulling the hook to where the surgery is performed. If the medial femur is cut and pulled away from the medial side, the bony landmarks are not revealed and the force line needs to be checked several times, otherwise the prosthesis installation position can easily travel, the large incision for conventional knee replacement is exposed and no special requirements are needed; most of the MIS small incision knee replacement surgeries cut the patella first, the tibia and finally the femur, the opposite order of bone cutting for conventional knee replacement. 3. The order of installing the prosthesis is different Conventional knee replacement usually installs the patella first, then the tibia and femur, and usually mixes the bone cement once to install all the prostheses; MIS small incision knee replacement surgery usually mixes the bone cement twice, and before mixing the bone cement, first installs the tibial prosthesis to determine how many degrees of flexion of the knee joint is most convenient to install, installs the tibial prosthesis to continue to pressurize, immediately clears The excess cement is then fully flexed and the femoral prosthesis is installed without difficulty before mixing the bone cement for the second time, installing the femoral prosthesis, and finally installing the patellar prosthesis. 4. The recent postoperative results are different. MIS small incision knee replacement surgery, immediately after anesthesia, can do straight leg elevation, recovery is fast; conventional knee replacement surgery after a week can do straight leg elevation, recovery is slow. There was no significant change in either after six months. Overall, MIS small incision knee replacement surgery has the advantages of less injury, less bleeding, faster recovery, and better function, but requires strict preoperative screening of the patient. Severely obese patients, patients with severe knee deformity, knee inversion greater than or valgus greater than or knee flexion contracture greater than 10°, knee activity prior to surgery and rheumatoid arthritis are not suitable for MIS small incision knee replacement and should only be done as a conventional knee replacement surgery.