Osteoarthritis of the knee is the most common joint lesion in the middle-aged and elderly in China, with the patellofemoral and medial tibiofemoral joints being the most common lesions. With the aging of our population, this disease is becoming more and more prominent. The active prevention and treatment of this disease is of great importance. Artificial joint replacement has been widely used for severe osteoarthritis of the knee, but is rejected by many patients due to the high cost, the risk of infection within 2 years after surgery (infection is devastating), and the unsuitability for younger patients under 60 years of age, among other disadvantages. The medial and lateral deformities produced by unicondylar knee osteoarthritis cause abnormal distribution of weight-bearing stresses in the joint, such as medial knee deformity, which causes a concentration of stresses on the medial side of the knee and accelerates joint degeneration on the medial side. When an external knee deformity occurs, the stresses on the lateral side of the joint are concentrated, causing accelerated degeneration of the lateral joint. High tibial osteotomy (HTO) for the treatment of osteoarthritic knee deformities in middle-aged and elderly knees has significant pain relief and functional improvement. The rapid disappearance of knee soreness after surgery may be directly related to the reduction of intraosseous pressure, improvement of local blood flow after surgery, and elimination of stasis phenomenon. It is a very effective surgical method for the treatment of unicompartmental osteoarthritis of the knee. Some patients with bicompartmental osteoarthritis can still be treated with osteotomy. The three main methods are the lateral closed wedge osteotomy, the domed osteotomy and the medial open wedge osteotomy. The biomechanical principle is: the osteotomy corrects the deformity, changes the line of gravity of the affected limb, corrects the poor alignment, corrects the uneven distribution of stress on the knee joint, redistributes the stress on the knee joint surface, shifts the load to the undamaged compartment, reduces the symptoms of osteoarthritis, and slows down the process of joint degeneration. The principle of tibial high osteotomy for internal knee valgus is to shift the weight line of the knee from the medial side to the normal knee weight line or slightly outward, which is a means to make full use of the favorable conditions of the healthy articular cartilage on the lateral side to partially repair the degenerating joint. Precise measurement of the osteotomy angle prior to surgery is critical to the success of the procedure. It has particular advantages for the treatment of the most common medial patellofemoral osteoarthritis of the knee. By reducing the pressure on the patellofemoral joint and correcting the inversion deformity in a single osteotomy, it can really reduce the symptoms of knee pain and restore joint mobility. Arthroplasty can be the first choice for those who do not like to be active, are older than 60 years old, and have severe deformities. In the absence of infection, it can be considered the ultimate treatment. The ultimate treatment after HTO surgery is the ability to allow the patient to perform various activities, such as sports, without restriction. In contrast to HTO, artificial joints have a limited life span and many young patients under the age of 60 are not candidates for joint replacement surgery. Biomechanical studies have shown that the surface load generated by activity (involving jumping and running) can exceed the limits of the polyethylene itself, and that the contact force generated by running is twice the body weight. When the knee joint is extremely flexed, the reaction force on the patellofemoral joint is nearly 8 times the body weight, and during activity, these forces act together on the artificial joint, thus causing fatigue in the structure of the artificial joint; in addition, repeated and frequent aggravating loads, such as continuous work, swinging and climbing, can endanger the artificial joint and make it loose. One of the advantages of HTO is that it allows the patient to continue to maintain a high level of mobility after surgery and to engage in high levels of physical activity, all safely. Therefore, if a patient with osteoarthritis of the knee wants to continue to participate in sports that involve jumping, running, etc. or occupations that require bending, digging, climbing, etc., HTO is definitely the best option. Some HTOs require placement of plates, extensive soft tissue debridement, long postoperative plaster immobilization and bed rest, and removal of internal fixation 1 to 2 years after surgery, which affects the near and long-term postoperative outcome. In order to overcome the above-mentioned shortcomings, according to the experience of our hospital, the external fixation brace was used instead, and the U-shaped osteotomy end was fixed with Meng’s external fixation brace, which can be used for early partial weight-bearing activities after surgery, avoiding joint stiffness and muscle atrophy brought about by the cast, and avoiding patients to perform secondary incision surgery to remove the internal fixation, and achieving satisfactory results. Any surgery is not a panacea, there are advantages and shortcomings, the recent effect is significant, the medium and long term effect can be better maintained, with the extension of time, the knee joint score is declining, but the high osteotomy delayed to do artificial total knee replacement, prolonging the life of their own knee joint. In conclusion, the advantages of HTO as a surgical method for treating osteoarthritis of the knee are quite obvious: (1) The osteotomy plane is located in cancellous bone, and the bone heals quickly after osteotomy, with a low incidence of non-union. (2) Functional exercises can be performed early after surgery to avoid post-operative knee adhesions. (3) The operation is simple and has few complications. (4) When the efficacy of surgery decreases, artificial knee replacement can still be performed in the second stage. (5) After the operation, it is still possible to engage in certain intensity of work, which is especially suitable for younger patients with osteoarthritis of the knee.