Some people often feel weak when going up and down stairs. If they don't hold the bracket quickly, they will kneel involuntarily, and the pain in their knees will be aggravated, especially in the semi-squatting posture. What's more, the knee joint can't bend and stretch suddenly during the activity. After a little activity, a crisp sound can appear under the patella. When you have the above symptoms, you may have patellofemoral arthritis of the knee. The activity of knee joint needs the participation of patella, and there are seven small joints above and below the patella that match the femoral articular surface. If they don't match, they will repeatedly rub and collide with each other, which will damage the articular cartilage and make it rough gradually, and then damage the soft tissue, synovial bursa and fat pad around the joint, naturally degenerate and lead to patellofemoral osteoarthritis, and even develop to the whole knee joint. Generally speaking, pain is the earliest information of knee joint diseases. If the pain is mild, conservative treatment can be taken. At this point, the patient's knees should rest properly to avoid overload; Pay attention to weather changes and avoid wet and cold; Protect the diseased joints with a sheath to avoid sedentary, standing for a long time and being inactive for a long time. It is very important to emphasize the functional exercise of lower limbs, and in principle, it is mainly active activities without load. In short, the patient can lie on his back, his legs are straight, his hands are naturally placed at his side, his toes are lifted, his straight legs are lifted up, and the angle is gradually increased. In the future, sandbags can be tied at the distal end of the calf to increase weight-bearing exercises; You can also sit on a fitness bike for pedaling activities to simulate pedaling. After a period of functional exercise, the knee joint can flex freely, prevent muscle atrophy, enhance muscle strength and increase joint range of motion. Patients should try to avoid some knee joint weight-bearing exercises, such as running. At the time of acute attack, patients can take anti-inflammatory and analgesic drugs orally, and can also be treated with drugs for external use or sodium hyaluronate injected into the joint cavity. If conservative treatment fails, if the knee joint has been slightly or moderately injured, surgical treatment should be considered, such as elevation and internal displacement of tibial tubercle. For patients with severe knee osteoarthritis, especially in the late stage, there is no doubt that total knee replacement can completely improve the function of knee joint, relieve pain, correct deformity and improve the quality of life of patients.