In recent years, with the continuous improvement of the technique of high tibial osteotomy (HTO, High Tibia Osteotomy) for the surgical treatment of early and mid-stage knee osteoarthritis with internal and external knee deformity, clinical results have been increasingly recognized and applied, with a short-term satisfaction rate of 80-99% and a long-term 15-year follow-up satisfaction rate of 71%. However, some authors have reported cases of failure, and analyzing the risk factors in the literature that affect the outcome of HTO, factors such as the patient’s age, body mass index, degree of joint pathology, and the angle of surgical correction of the deformity may affect the outcome of PTO. High medial tibial osteotomy support implant for knee osteoarthritis with inversion deformity. Indications: Patients with osteoarthritis of the knee under 65 years of age who are not overly obese, do not have severe bone loss in knee degeneration, do not have significant internal or external knee valgus with flexion contracture deformity, do not have severe knee ligament disorders, and do not have significant patellofemoral degeneration. Although the clinical results of proximal tibial high lateral closed wedge osteotomy for internal knee deformity reached 84% at about 10 years, and the excellent clinical results also reached 64%, most scholars prefer high medial tibial open brace osteotomy. The proximal medial tibial osteotomy with open support implant is more accurate than the lateral closed wedge osteotomy in correcting the valgus angle of the knee. Especially in the presence of chronic knee instability, the postoperative clinical results of a high lateral closed tibial osteotomy are significantly inferior to those of a proximal medial tibial osteotomy with a brace graft. Dejour’s treatment of osteoarthritis of the knee with anterior instability using a proximal medial tibial osteotomy with bracing reduced the tibial articular surface tilt angle and achieved satisfactory results. In addition, the proximal medial tibial osteotomy brace implant does not remove bone and can maintain the anatomical and morphological integrity of the tibia, which can provide bone volume and joint morphology structure for possible subsequent total knee replacement. At the same time, truncation of the broken end gap, i.e., between the medial aspect of the knee gap and the tibial stop of the medial collateral ligament of the knee, and grafting of two bicortical iliac blocks can restore the tension of the medial knee ligament. There are many factors affecting the clinical outcome after HTO, including the patient’s age, weight, joint space, corrected knee valgus angle, and osteotomy fixation method, which may affect the postoperative outcome. A. Patient age: Patients who are younger at the time of surgery tend to have better clinical outcomes, which may be related to the smoother postoperative recovery when the patient is younger. The mean postoperative HSS scores of the lower age group under 50 years old in our group were higher than the scores of the higher age group, but there was no statistically significant difference. Patients with osteoarthritis of the knee who are 65 years of age or older, especially female patients, are often prone to have osteoporosis in combination, and HTO treatment should be chosen with caution at this time. If osteoarthritis of the knee is severe and combined with osteoporosis, total knee arthroplasty may be a better option. Post-operative anti-osteoporosis treatment is also required. Second, body mass index factors: weight non-overweight and low age groups show better clinical outcomes after surgery. As the patient’s weight increases, there is a significant negative effect on the postoperative knee loading, which can increase the irritating stress on the articular cartilage, promote wear and tear, and accelerate the progression of arthritis. Therefore, weight control in patients with osteoarthritis of the knee is one of the important factors to ensure a good outcome after HTO. After HTO, patients need to take appropriate measures to avoid weight gain; if the preoperative body mass index BMI is already over 25 kg/m2 in patients, more attention should be paid to measures to reduce weight after HTO to reduce the adverse stimulating effects of weight stress on the knee joint and avoid damage to osteoarticular cartilage and the progression of osteoarthritis and recurrence of internal knee deformity. Third, the knee joint gap: The degree of knee osteoarthritis on preoperative radiographic imaging has an impact on the early clinical outcome after osteotomy. In this study, satisfactory clinical outcomes were obtained in Ahlbäck grade 1 patients with mild preoperative knee gap narrowing and in patients with postoperative knee valgus angle correction to 8° or greater. If the medial joint space is significantly narrowed, Ahlbäck grade 1 or higher, then it predicts severe arthritis, significant wear and tear of the articular cartilage, and damage to the meniscus. Although HTO reduces the stress effect on the medial joint surface by changing the lower extremity force lines, it is more difficult to recover from the symptoms of arthritic injury. At the same time of HTO, performing arthroscopic joint cleaning of the knee, microfracture treatment or cartilage grafting of the articular cartilage defect area, while trimming and shaping the damaged meniscus, can improve the postoperative functional rehabilitation of the knee after surgery. Postoperative application of high-frequency ultrasound for postoperative physiotherapy of the knee joint can effectively eliminate swelling of the joint and promote joint recovery. Regular postoperative intra-articular injection of sodium vitrate every six months in the knee joint can protect joint cartilage and relieve knee pain symptoms by inhibiting the secretion of inflammatory factors such as TNF-α and IL-1β. When the femoral-tibial angle (knee valgus angle) exceeds 5° after HTO, the biological axial force line of the lower limb is restored, and the load stress of the two inter-articular compartments inside and outside the knee joint is reasonably distributed, which can effectively relieve knee pain and improve the quality of life, however, it does not promote the repair of the damaged articular cartilage. Most scholars advocate that the knee valgus angle is overcorrected by 5° compared to 5-8° at normal and controlled within 15°. In order to obtain precise osteotomy angle and correction angle, computer navigation-assisted high tibial osteotomy is even more advantageous with minimal deviation, which is recognized by scholars. Therefore, when performing HTO to correct internal knee deformity, it is recommended that the knee valgus angle be corrected to about 8° of valgus, so that even if some angle is lost by postoperative weight bearing, the valgus angle can be maintained at no less than 5°, thus lessening the adverse stress stimulation to the medial compartment of the knee. The use of an autologous iliac bone block embedded in the osteotomy break and the maintenance of the knee valgus angle after internal fixation of the plate stabilized the osteotomy end and promoted the healing of the osteotomy end. However, increased posterior tibial plateau and decreased patellofemoral distance often occur after HTO, which affects the extension function of the joint. The lateral cortex of the tibia should not be completely truncated during the osteotomy treatment, and some of it should be retained, and the lateral side should be hinge-like change when the medial side is propped up, so that the posterior tilt angle of the tibial plateau of the knee should not change as much as possible, and the stability of the osteotomy end should be maintained during bone grafting and plate internal fixation. Proximal medial tibial osteotomy with osteotomy and implant is simple and can adequately correct the valgus angle of the knee. The stability of the osteotomy end after bone grafting and plate fixation effectively inhibits the recurrence of valgus deformity and delays the progress of osteoarthritis of the knee. The patient’s age, body mass index, degree of preoperative knee gap change and postoperative knee valgus angle can affect the postoperative outcome, therefore, the indications for HTO surgery should be selected appropriately and the intraoperative osteotomy operation should be precise.