For some patients with unicondylar osteoarthritis due to force line misalignment in the lower extremity, a high tibial osteotomy may be an option if there is a high demand for athletic ability. A high tibial osteotomy is an osteotomy technique where the plane of osteotomy is above the tibial tuberosity. The rationale is to correct abnormal loading stresses in the coronal plane of the knee due to an abnormal tibiofemoral axis, and inversion or valgus angulation of the lower extremity can produce and exacerbate this abnormal loading, followed by osteoarthritis. Patient selection: Patients under 60 years of age with unicondylar osteoarthritis with greater than 90 degrees of joint mobility, less than 40 degrees of flexion deformity, good joint stability and mobility; knee pain and ineffective conservative treatment; sustained walking distance of 500 meters or less. Tibial high osteotomy is a technique that makes full use of the favorable conditions of the healthy cartilage of the knee joint to repair some of the degenerating cartilage, which can reduce symptoms and delay the development of osteoarthritis, and may be a measure to delay or eliminate joint replacement for patients under 60. In today’s increasingly aging society, this technique is worth promoting.