Many middle-aged and elderly people suffer from knee pain, and many of them are fine walking on flat ground, but their knees hurt when going up and down stairs, and others have knee pain when squatting, and they are afraid to pick up anything they drop, which is actually a typical manifestation of osteoarthritis of the patellofemoral joint. The patellofemoral joint is part of the knee joint, consisting of the patella (commonly known as the kneecap) and the femur, which mainly plays a role in the process of flexion to extension of the knee joint. Studies have shown that the stress it bears when walking on flat ground is about half of a person’s weight, but when walking up and down stairs, this value can reach 3.3 times the weight, which explains why the pain mainly occurs when walking up and down stairs and squatting. In women, due to their wider pelvis, many have problems with the patella tilting and shifting laterally, and as they age, the lateral patellofemoral joint gradually wears and degenerates and shows symptoms. As a chronic disease, osteoarthritis of the patellofemoral joint is prolonged and gradually worsens, affecting the quality of life and even causing disability in severe cases, so once symptoms such as painful walking up and down stairs and squatting occur, prompt medical attention should be sought. For these patients, there are several treatment methods. The first is lifestyle modification. For example, minimizing activities that can trigger knee pain such as hiking and squatting; holding handrails when going up and down stairs to reduce the force on the knee joint, or even considering changing to a lower floor or elevator-equipped residence if possible; and keeping warm by wearing knee pads when going out in winter. By doing these simple things, many patients can significantly reduce the frequency of knee pain episodes. Next, exercise the muscles around the knee, especially the quadriceps in front of the thigh, to increase muscle strength and reduce the burden on the patellofemoral joint surface. The easiest way is to do straight leg raise training by lying down, tensing the muscles in the front of the thigh so that the heel leaves the bed about 250px, and insisting on 15-20 seconds, 3 groups of 15-30 times per day. For patients whose pain is not easily controlled, medication can be used under the guidance of the doctor: such as taking anti-inflammatory and pain-relieving drugs to reduce pain, oral glucosamine to promote cartilage repair, joint cavity injection of sodium hyaluronate to lubricate the joint, and joint cavity closure treatment is also feasible for some patients with more severe pain and swelling. Finally, surgical treatment can be considered for those patients with severe pain who have failed conservative treatment. Artificial knee arthroplasty can completely relieve pain and improve joint function, and is the best choice for advanced knee lesions; if the lesion is confined to the patellofemoral joint, patellofemoral joint unicompartmental replacement is an emerging technique that has emerged in recent years. It is a new technique that has emerged in recent years.