Knee pain can be caused by trauma, knee arthritis, other knee diseases and so on. 1. Trauma: due to the trauma caused by the patient’s knee injury, such as medial and lateral collateral ligaments, fat pads, meniscus and other tissue damage, the patient may appear knee pain, joint interlocking and activity limitation and other symptoms. 2. Knee arthritis: common in osteoarthritis, rheumatism and rheumatoid arthritis and other inflammatory joint lesions, due to cartilage degeneration, inflammation stimulation and bone spur formation, resulting in joint space narrowing and irritation of the surrounding tissues, the patient may appear knee pain symptoms. 3. Other diseases of the knee joint: such as meniscus cysts, knee infections, tuberculosis and tumor diseases, can cause patients with knee joint bone and surrounding tissue changes, the patient may also have symptoms of knee pain. There may be other reasons for knee pain, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.