Most of the patients with “old cold leg” are over 45 years old and have a slow onset. Both sides or one side of the knee joint often have hidden pain, which is aggravated by activity and improves after rest. The symptoms are worse when it rains on cloudy days, so they are very afraid of cold and put on woolen pants early in early autumn. Sometimes the pain is acute and the joint is stiff, with a popping sound when moving. The stiffness of the joints increases after sitting for a long time, but improves slightly after moving around. In the late stage, the joints swell and movement is limited. With the growth of life expectancy in China, “old cold leg” has become a popular orthopedic problem. In winter outpatient clinics, “old cold leg” accounts for a considerable proportion. The “cold leg” is a common name, but its “proper” name is degenerative arthritis of the knee joint, or osteoarthritis, or osteoarthrosis of the knee joint. The knee joint is the largest joint in the body, located between the hip and ankle joints of the lower limbs, heavy burden, high activity, joint cartilage is prone to gradual wear and tear, destruction. Congenital developmental defects of the waist or lower limbs (such as congenital hip dislocation), or joint injuries (such as fractures and dislocations), inflammatory diseases (such as septic arthritis and rheumatoid disease), etc., can make the joint contact surface unsmooth and the line of negative gravity change, which is an important trigger for degenerative arthritis of the knee. Although joint degeneration is an inevitable process in life, the limitation of knee movement will seriously affect work and life, so it is necessary to strengthen prevention, take various measures to delay the occurrence of the disease, reduce the extent of the disease, delay the development and improve the quality of life. What should I do if I have “old cold leg”? First of all, the bone and joint deformities or diseases of the lower limbs should be treated early, and attention should be paid to prevent trauma or overexertion. After middle age, especially should pay attention to the regularity of life, often appropriate activities, can promote joint cartilage absorption of nutrients, and maintain the range of joint movement. At the same time, it is important to combine work and rest to avoid too much activity and damage to the joints. You can choose to play tai chi, jogging, walking, gymnastics and other exercises, and be persistent. Ensure sleep and nutrition, moderate diet, and prevent excessive obesity to reduce the weight on the joints. Crutches can also reduce the burden on the joints. To prevent the joints from being attacked by cold and damp, use knee pads. If you feel discomfort in the knee joint, you should go to the hospital as soon as possible. If the pain is severe, you can take medications such as anti-inflammatory pain, ibuprofen, and limethasone as prescribed by your doctor. If there is fluid in the joint, the fluid can be extracted and drugs such as prednisolone can be injected at the same time. But remember, although this drug can control the symptoms more quickly, it has adverse effects on the joint cartilage and should not be applied continuously or in large quantities. Sodium vitrate injection has the ability to lubricate and nourish the joint, and intra-articular injection has good effect. Physiotherapy can be used if necessary, with reliable effect and small side effects. Hot spring water temperature is suitable, containing a variety of chemical substances, hot spring spa can accelerate blood circulation, inhibit inflammation, favorable recovery. Ancestral medicine believes that the kidney collects the essence of the main bone. Older people have a lack of qi and blood, liver and kidney deficiency, wind, cold and dampness can easily invade, blocking the meridians, paralysis occurs. It is advisable to use traditional Chinese medicine to relax the tendons and channels, dispel cold and dampness. Commonly used Chinese medicines include Tianma Duzhong Pill, Zhuangjian Pill, Shujian and Blood Pill, etc. Musk chasing wind cream, dog skin cream, wound and dampness pain relief cream can also be applied externally, or apply whole bone water, safflower oil, etc. If the symptoms are serious, joint lavage can be done. It is especially recommended to remove part of the synovial membrane and hyperplasia under arthroscopy, to trim and smooth the cartilage, or to drill and implant bone to promote regeneration. Some patients are suitable for osteotomy to change the line of negative gravity. If the joint function is very poor, artificial joint replacement can be performed.