The knee joint, commonly known as the “knee”, is the largest and most complex joint in the body. The knee joint is a hinge joint, and it is one of the few joints in our body that can only move in one direction. The knee joint is also the largest weight-bearing joint in the body, with a normal human knee joint being able to support an average of 35 kg of weight. The more weight you carry, the greater the chance of wear and tear on the articular cartilage, the more likely it is that your tendons will be injured, and the faster your knee joint will degenerate. Articular cartilage is a 3 to 5 mm thick layer of transparent material on the surface of the bones that make up the human knee joint, and its main function is to cushion the impact of knee movement. If the knee joint feels significant pain, it means that the cartilage has reached the end of its “useful life” and the cartilage has worn away and lost its protection of the bone. The meniscus is two crescent-shaped fibrocartilages between the femoral condyles and the tibial plateau, and is located on the medial and lateral articular surfaces of the tibial plateau. The function of the meniscus is to stabilize the knee joint, cushion the knee joint from loading forces, and promote intra-articular nutrition. It is the stabilizing effect of the meniscus that ensures that the knee joint does not become damaged during years of weight-bearing exercise. The medial meniscus degenerates earlier because 60% of the body’s weight is supported by the medial side of the knee. Because of the nerve distribution in the meniscus, people can feel the pain during the degeneration process. 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, and the joint cartilage and bone surfaces rub together for a long period of time, resulting in a “clicking” sound or frictional sound when moving. Chronic inflammation in the joint leads to fibrous adhesions in the peri-articular tissues, which can cause stiffness in the knee joint and even lead to joint deformity and disability. More than half of the patients come to the clinic each week with knee problems. The degeneration of the knee joint is not well understood. The knee joint is like one of the bearings. After a long time, the steel ball, sleeve and seat inside the bearing wear out (the steel ball is like the meniscus, the sleeve is like the cartilage, and the seat is like the bone). Some patients see people around them who are older than they are, but they do not have any pain in their knee joints and they walk freely. What if the knee joint degenerates? What if the bearings of the machine are broken? At first to carefully check to find the cause, is the machine with a long time parts aging, then to the machine maintenance maintenance, screwing, add some lubricant to the bearings. The machine is aging to continue to use, it must be used sparingly. When the knee joint just appears sore, pay attention to maintenance, do not walk too long, when the knee feels uncomfortable should immediately rest; do not do a large amount of exercise, such as running, high jump, long jump; avoid half squat, full squat or kneeling position, such as squatting horse stance; maintain the ideal weight to reduce the burden on the knee; pay attention to the knee warmth, you can wear long pants, knee pads to protect the knee; less heavy lifting, less wearing high heels; avoid Avoid trauma and overwork. If the symptoms of pain are serious, you can take anti-inflammatory drugs to relieve pain and promote the metabolism of cartilage, but be aware that prolonged use of anti-inflammatory drugs for pain and gastrointestinal tract stimulation, pay attention to take drugs after meals; intra-articular injection of sodium vitreous acid injection, can increase joint lubrication, reduce the wear and tear of joint cartilage. If the machine is still not working after maintenance, then you need to ask the master to repair the machine! This means that if the knee joint is still painful after conservative treatment, then surgery is required. A doctor is like a repairman, and repair is surgery. Master repair first of all to disassemble the bearing check to see inside the steel ball, sleeve and bearing seat is bad or wear aging, according to the situation to decide whether it can still be repaired. If you can repair, first repair a temporary use, if not, according to the bad parts and degree of decision is to replace the ball, sleeve or bearing seat single parts, or the entire bearing are replaced. The doctor’s method of repair is minimally invasive arthroscopic surgery, which involves making two small incisions in the joint and placing a small mirror inside the joint to check the wear and aging of the structures inside the joint, and depending on the situation, decide whether to simply repair or replace the parts, which is unicondylar joint replacement or patellofemoral joint replacement. If the repair is not good or if the bearing is not working, the last move is to replace the surface of the knee with an artificial one.