Since the early 1970s, total knee arthroplasty has evolved into an important method of reconstructing knee function. Minimally Invasive Surgery Total Knee Arthroplasty (MIS TKA), with a surgical incision of less than 5 inches, is a completely new approach to total knee replacement. We have had success with unicondylar knee replacement using a minimally invasive incision. Currently, unicondylar knee replacement using minimally invasive techniques has become a popular surgical approach, and short-term clinical outcomes have been reported in the literature to be at least as good as those of traditional standard unicondylar knee replacement. With the success of minimally invasive unicondylar knee replacement, we began to explore the use of minimally invasive techniques for total knee arthroplasty. Using a minimally invasive technique of lateral osteotomy from the femur with an extramedullary tibial guide rod, we successfully completed a total knee arthroplasty. With the development of a new set of surgical instruments based on minimally invasive techniques for total knee arthroplasty, it is very convenient to perform TKA with minimally invasive techniques. With the development of special instruments for MIS TKA and the standardization of operating techniques, the MIS TKA technique has matured and represents the latest technology in this field. 1. Advantages of MIS TKA The minimally invasive technique is not based solely on the size of the surgical incision and the cosmetic outcome, but rather on the minimal invasion of the anatomical structures of the involved joints. The operation of MIS TKA does not invade the knee extensor mechanism or the suprapatellar capsule. If a minimally invasive technique is performed to manipulate the incision of the joint capsule, invasion of the knee extensor apparatus, the suprapatellar capsule and the use of a restrictive incision to externally rotate the patella are not truly minimally invasive techniques. The main concerns of patients undergoing TKA are postoperative knee pain and the time required to restore joint function, as well as the long-term function of the joint. MIS TKA is a new technique, and although there are differences in operating methods and surgical instruments between surgeons, and postoperative follow-up and evaluation are short-term and limited, MIS TKA has unique advantages over traditional TKA. However, MIS TKA has unique advantages over conventional TKA: (1) minimal surgical debridement trauma, minimal invasion of the anatomical structures of the important knee extensor apparatus, more stable knee joint and better recovery of joint function after surgery. ② Minimal skin incision scarring to meet the cosmetic requirements of the patient. ③Reduced intraoperative and postoperative blood loss. ④ Reduced pain level. ⑤ Early functional movement of the knee joint is possible. ⑥Shortened hospitalization time and reduced medical costs. ⑦ The advantages of more obvious early efficacy and less surgical sequelae. 2. Indications for MIS TKA Indications for MIS TKA are mainly for patients who are undergoing initial knee replacement. Specific requirements include a knee with a range of motion of 110° or greater (10° or less for knee flexion deformity and 125° or greater for flexion), 10° or less for knee valgus deformity and 15° or less for knee valgus deformity. Minimally invasive surgery is contraindicated in patients with a combination of reduced bone mass and inflammatory osteoarthritis. MIS TKA should be avoided if possible in overly obese patients (over 180 pounds), not only with regard to weight alone, but also with regard to excessive knee circumference. For patients who are too old or have problems with important organs, MIS TKA is not advocated due to the long duration of minimally invasive surgery. 3. Surgical techniques for MIS TKA All preoperative preparations are required to be more complete. In addition to routine radiographic examination, 3D reconstruction of the knee joint with CT is performed if necessary to understand the condition of the knee joint, femur and tibia, and then to develop the best surgical plan. The surgical approach and method of operation for MIS TKA varies slightly from one academic to another, and can be divided into medial and lateral approaches to the knee. Since most of the traditional TKA surgical approaches use the medial knee approach, MIS TKA also started and developed from the medial knee approach, including surgical techniques and surgical instruments, which were designed around this approach. Therefore, only after the operator has mastered the medial knee approach and gained insight should he or she attempt MIS TKA using the lateral knee approach. The surgical approach Borrowing from the position of knee arthroscopy, it is easier to perform soft tissue balancing by placing the affected limb on a lower extremity support brace and draping the lower leg to increase the knee gap by gravity, making it easier for the operator to observe the posterior soft tissues of the joint. Advantages. Using the support frame, a circular support bar is padded behind the affected knee, maintaining a position of 20-30° hip flexion and 90-100° knee flexion. A skin incision approximately 6-12 cm long is made medially in front of the knee using a transmedial femoral approach. The medial femoral oblique muscle is cut approximately 2 cm, and the joint capsule is incised to expose the joint cavity. The tibial osteotomy is performed first, followed by the femoral osteotomy. The osteotomy is performed with the knee joint in flexion and extension, and the osteotomy is relatively easy to perform. After the femoral prosthesis of the knee is placed, the tibial side of the prosthesis is then placed and the rotational alignment is adjusted. The tibial plateau is prepared in this position for fixation of the tibial prosthesis. The joint space is maintained using the module and a soft tissue balancing operation is performed to make both sides of the knee symmetrical. Next, the patellofemoral articular surface is osteotomized and the patellofemoral prosthesis is fixed. The rest of the procedure is similar to conventional TKA. Postoperative rehabilitation measures for MIS TKA The postoperative rehabilitation measures for MIS TKA are to allow the patient to be mobile 2 hours after surgery. Knee braking is not necessary to facilitate patient movement. The plasma drain can be removed on the second postoperative day, antibiotics are applied to prevent infection, and measures to prevent deep vein thrombosis are used, all of which are the same as the postoperative measures for conventional TKA. Therapeutic results of MIS TKA MIS TKA can achieve good early results. (1) Reduction in surgical blood loss. In the reported 58 cases of MIS TKA, the average operative time was 110 minutes; the average blood loss was 200 cc, which is half of the blood loss of traditional TKA surgical operation. (2) The postoperative knee pain index was reduced, and the reliance on pain medication was also significantly lower. (2) Early recovery of knee function was significantly faster in the MIS TKA group than in the conventional TKA; three months after surgery, the knee could be flexed to an average of 116° in the MIS TKA group, compared with an average of 97° in the conventional TKA; at one year after surgery, joint mobility had reached 125° (110°-135°) in the MIS TKA, compared with 116° (95°-130°) in the conventional group. 95° to 130°). Although it is still too early to judge the long-term results of using MIS TKA, the obvious early results, especially with the advantages of less surgical trauma, early mobility, and fewer surgical sequelae, have given momentum to this technique. The smaller surgical incision requires a change in the surgical approach and the specialization of surgical instruments. New operating techniques require the development of appropriate knee prostheses and computer-assisted techniques, thus changing the traditional model of knee replacement. MIS TKA should be performed with proper selection of surgical indications, preoperative CT scan of the knee to determine the condition of the knee joint, femur and tibia, gentle operation to minimize soft tissue damage, complete removal of excess cement from the margins, and minimization of surgical complications. Operators need to be trained in the specialized surgical skills necessary to perform MIS TKA proficiently. With the development and development of MIS TKA surgical instruments, standardization of surgical operations, and, aided by computer technology-based navigation systems, the development and application of surgical techniques in MIS TKA has resulted in more precise MIS TKA operations and more minimal damage to joint structures and surrounding soft tissues, achieving no early clinical failures or complications. Through standardized development, MIS TKA eventually becomes the future mainstream surgical direction.