Knee pain may be due to physiological reasons such as growing pains, or it may be caused by trauma, knee inflammation, knee tumors and other pathological reasons. 1. Growing pains: most commonly seen in ligament and bone growth mismatch caused by children feel a circle of the knee running with pain growing pains, generally do not need to deal with. 2. Trauma: trauma leads to tendon, ligament, meniscus, bone and other tissue damage, the patient may appear to the knee a circle running pain. 3. Inflammation of the knee joint: If the knee joint is involved in osteoarthritis, rheumatoid osteoarthritis, rheumatoid arthritis and other diseases caused by degenerative changes of the knee joint, the patient may have pain in a circle of the knee. 4. Tumor around the knee joint: such as patella and epiphysis osteosarcoma, soft tissue sarcoma and other diseases, patients can appear a circle of running 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.