It is estimated that there are currently 100 million people with osteoarthritis in China. Osteoarthritis, also known as degenerative joint disease, proliferative osteoarthritis, or “joint spurs”, has a prevalence of 9.56% in the knee joint and 78.5% in people over 60 years of age. The disease starts slowly. Symptoms appear mostly after the age of 40, but the incidence increases with age. The incidence is higher in women than in men. Arthralgia in this disease has the following characteristics: it occurs mostly in weight-bearing joints such as knees and hips; arthralgia is related to activity, and the pain is relieved after rest; after the joints have been stationary for a long time and then moved, there is a transient local stiffness that lasts no more than 30 minutes and disappears after activity; in severe cases, even at rest, there is arthralgia and limitation of activity; the affected joints are often accompanied by pressure pain, bony hypertrophy, bony friction sounds, and a few patients have deformity. A small number of patients have deformities. If not taken seriously, the consequences are likely to be chronic and disabling. For this reason, some scholars refer to it as the “cancer that never dies”. Osteoarthrosis is a painful condition that causes patients to suffer from pain all day long. Many patients are unable to walk and are forced to choose total knee replacement surgery. In fact, a significant number of patients with osteoarthrosis do not need a total knee replacement and can opt for a “unicondylar replacement”. The unicondylar arthroplasty is a surface replacement of only one diseased compartment of the tibial joint, i.e., it does not interfere with other normal or near-normal parts of the knee joint, thus providing maximum benefit with minimal trauma and solving a major problem for the patient. It also avoids the overtreatment of total knee arthroplasty and even replaces it. The opportunity for future total knee arthroplasty is preserved even more for patients of younger age and less severe disease. Cartilage wear in the knee is concentrated early on in the anteromedial tibial plateau, the medial compartment. Unicondylar arthroplasty is a minimally invasive procedure that replaces only a small portion of the medial knee under the guidance of precision instruments, resulting in less invasive surgery, faster recovery, fewer complications, and better postoperative function. The unicondylar arthroplasty preserves the amount of bone and preserves the internal ligaments of the knee joint, leaving room for future treatment. The patient feels good and more like his or her own joint after surgery.