Knee preservation surgery mainly includes arthroscopic cleanup surgery, high tibial osteotomy surgery, and unicondylar replacement surgery. Arthroscopic surgery is mainly for patients with mild joint degeneration, combined with meniscus injury and joint free body, which plays a role in cleaning up, reducing the wear and tear of the joint, and stopping the joint degeneration too fast. As for the high tibial osteotomy, it is for patients with inversion deformity of the proximal tibia of the knee joint, with wear and tear of the articular surfaces but with most of the cartilage intact, and it mainly corrects the coronal plane deformity. By correcting the lower extremity line of force, the point of force on the lower extremity line of force is shifted from the medial aspect of the knee joint to the midpoint of the knee joint or to the lateral aspect of the knee joint, i.e., 62.5% of the lateral aspect of the plateau, which is also known as the Fujisawa point. Orthopaedic osteotomies are not restricted by age and can be performed in patients with epiphyseal closure. There are also patients who need to undergo this procedure in conjunction with arthroscopic surgery to achieve better results. Unicondylar replacement surgery is for relatively young patients or older patients with wear of the knee joint surfaces on the medial or lateral side, but rather anteriorly or in the middle of the knee joint plateau, and for patients in whom the damage has reached the level of bone rubbing, with the typical symptom of walking pain, but no pain without weight-bearing, and such a patient can be relieved of his symptoms by arthroplasty, i.e., unicondylar replacement surgery. Postoperatively, the patient’s proprioception, mobility, self-score, and postoperative rehabilitative function exceed that of patients with total knee replacement.