The knee, the largest and most complex joint in the human body, is a hinge joint, and it is one of the few joints in our body that can only move in one direction. The knee is also the largest weight-bearing joint in the human body, and the average weight-bearing capacity of a normal person’s knee is 35 kilograms. The more weight you bear, the greater the chance of wear and tear of the articular cartilage, and the tendons are also prone to injury, and the knee joint degenerates faster. The weight-bearing capacity of the knee is as follows: 1. When lying down, the weight-bearing capacity of the knee is almost 0. 2. When standing up and walking, the weight-bearing capacity of the knee is about 1 to 2 times. 3. 3. When going up and down a slope or up and down a flight of steps, the weight on the knees is about 3 to 4 times as much as the weight on the knees. 4.When running, the weight of the knee is about 4 times. 5.When playing soccer, the weight on the knees is about 6 times. 6. When squatting or kneeling, the weight on the knees is about 8 times. The human knee joint quality has 15 years of the best state Before 15 years old: the knee joint is in the development stage, puberty growing pains mostly occur near the knee joint. From 15 to 30 years old: The knee joint is in a “perfect state” and works tirelessly. As long as it doesn’t damage the knee joint tissues, you basically can’t feel its existence. 30~40 years old: The patellar cartilage has early and mild wear and tear, and there will be a period of vulnerability, with short-term knee pain that lasts for a few weeks to a few months, and some people may not even be aware of it. The patellofemoral cartilage is a 3 to 5 millimeter thick layer of transparent cartilage in the human knee joint that cushions the knee from the impact of movement. But because the patellar cartilage has no nerve distribution, so in the whole layer before the wear and tear will only be in the fragile period of pulling a “warning signal”, in this period to avoid strenuous exercise. From this time onwards, you can no longer use your knee as you wish. Age 40-50: After walking long distances, the inner side of the knee tends to become sore, which can be relieved by gently rubbing it with your hands. In the knee joint, the meniscus serves to cushion vibrations and maintain stability. Since 60% of the body’s weight is supported by the inside of the knee, degeneration of the meniscus occurs earlier. And because there are nerves in the meniscus, one can feel the soreness during the degeneration process. The arrival of this phenomenon reminds people that it is time to start taking care of their joints. Above 50 years old: knee joint will feel obvious pain, this is because the patellar cartilage “service life” has come, the cartilage all layers of the middle-aged and elderly causes of knee pain After middle age, the knee tendons, ligaments began to degenerative changes in the joint cavity of the synovial fluid secretion is reduced, long-term friction of the articular surface of the bone to form the wear and tear of the bone, the joints of the surrounding tissues due to inflammation and other reasons are prone to occur. Tissue due to inflammation and other reasons are prone to fibrous adhesions, so the elderly often feel stiffness in the knee joint. Activity will be issued “click” sound or friction sound, in the cold or excessive activities will induce pain, swelling, joint cavity fluid, serious will also make the elderly joint deformity, the formation of disability. Specifically, the causes of knee pain in middle-aged and elderly people are as follows: 1, chronic synovitis: manifested as chronic pain and swelling of the knee joint. The examination can see synovial effusion and synovial hypertrophy. 2.Patellar deviation: the knee joint is sore and weak after activity, it is better after rest, and it is painful when half squatting. 3.Knee joint free body: the patient’s leg is weak or there is a sense of joint jamming, and there is friction sound under the patella. 4.Pre-patellar bursitis: there is a history of trauma, which causes pre-patellar pain and localized pressure pain on examination. 5.Osteoarthropathy: joint pain is obvious when standing up or going up and down stairs after sitting or squatting for a long time, and relieved after resting. 6.Pseudogout: male patients are more, preferably in the knee joint. It is characterized by swelling and pain, high skin temperature and functional limitation. x-ray film shows calcification of meniscus and articular cartilage surface. 7, femoral head necrosis: hip joint lesions with knee pain symptoms. Knee pain in different parts of the knee joint 1, iliotibial band pain on the outside of the knee. 2, anterior knee pain around the knee, also called patellofemoral joint pain. 3, Pain above the knee, possibly quadriceps tendonitis. 4, pain above the kneecap or on the inside of the upper tibia, may be bursitis. Daily health care for sore knees: 1, don’t walk for too long on the road, and rest immediately when your knees feel uncomfortable. 2.Do not do heavy exercise, such as running, high jump, long jump. 3, avoid half squatting, full squatting or kneeling position. Such as squatting horse stance. 4, do not do the knee joint half-flexion position rotation action, to prevent half plate injury. 5.Maintain ideal body weight to reduce the burden on the knee. 6, pay attention to the warmth of the knee, you can wear long pants, knee pads to protect the knee. 7, less heavy lifting, less wearing high heels.