A unicondylar knee replacement is a type of artificial joint replacement. It replaces only part of the worn and necrotic articular cartilage and part of the bone tissue, and the most frequently replaced part is the medial condyle of the knee. Because only the medial condyle is replaced, all the ligaments and tendons of the knee joint are left intact, so the patient recovers quickly, with minimal trauma and pain. After the surgery, the patient moved very much like a normal person and was able to squat and go up and down stairs freely. Of course it is not suitable for severe knee lesions, for patients with deformities of more than 15 degrees, for patients with multiple interval destruction of the knee, and for patients with unstable knees. I recommend it for patients with milder disease, younger age and less deformity.