After middle age, the tendons and ligaments of the knee joint begin to undergo degenerative changes, the synovial fluid secretion in the joint cavity decreases, the bone surface of the joint rubs together for a long time to form bone wear, and the tissues around the joint are prone to fibrous adhesions due to inflammation. This can lead to pain, swelling, and joint fluid accumulation when exposed to cold or excessive activity, and in severe cases, it can cause joint deformity and disability. Specifically, the causes of knee pain in the elderly are as follows: 1. Chronic synovitis Chronic pain and swelling of the knee joint. Synovial effusion and synovial hypertrophy can be seen on physical examination. 2, patellar deviation, soreness and weakness of the knee joint after activity, improving after rest, pain during half squatting. 3, free body in the knee joint The patient’s leg is weak or has a feeling of joint jamming, and there is a friction sound under the patella. 4, prepatellar bursitis History of previous trauma, causing prepatellar pain, localized pressure pain on examination. 5, osteoarthrosis After sitting or squatting for a long time, when standing up or going up and down, the joint pain is obvious and relieved after rest. 6, pseudogout More male patients, mostly in the knee joint. X-ray film shows calcification of meniscus and articular cartilage surface.