Pain when bending the knee, if it is caused by knee infection, you can take proper rest and medication; if it is caused by traumatic injury to the meniscus damage caused by pain, you can rest, physical therapy, take medication; serious meniscus tear caused by pain, need to use surgical treatment. 1. Knee infection: after knee infection, there may be different degrees of pain when bending, proper rest and knee braking are needed, while anti-infection treatment is carried out, anti-inflammatory drugs such as aspirin and bisacodyl can be used to relieve the pain as prescribed by the doctor. 2. Trauma caused by meniscus injury: this can be appropriate rest, through massage and infrared radiation to speed up blood circulation to improve the pain, for serious pain can be oral aspirin, salicylate and other drugs. 3. Pain caused by serious meniscus tear: this disease is relatively serious, if the effect of conservative treatment is not good, surgery can be used. In addition, the pain when bending the knee joint can be caused by other reasons, it is recommended to go to the hospital for examination in time, after clarifying the cause, and then deal with it accordingly.