The knee pain after running may be caused by synovitis, meniscus injury and patellar injury, which can be treated by taking non-steroidal anti-inflammatory drugs, painkillers and cartilage nutrients, and synovitis and meniscus injuries can also be treated by surgery. 1. synovitis: synovitis may be caused by knee sprains, when after running if the posture is not right will aggravate the bearing strength of the knee, will make the condition worse, thus appearing after running knee pain a bending of the symptom, you can take indomethacin for treatment, when the patient is not sensitive to the drug, you can choose to surgery to carry out the treatment. 2. Meniscus injury: meniscus injury may be caused by long-term large number of sports, will appear after running the phenomenon of knee pain when bending, you can take ibuprofen extended-release capsules to relieve the pain, if the condition is serious, you can choose surgery to carry out treatment. 3. patellar injury: patellar injury may be caused by a large number of sports, may also be caused by trauma, will appear after running knee pain symptoms, you can take glucosamine hydrochloride tablets for treatment. There may be many reasons for knee pain after running and bending, and it is recommended to consult a doctor in time to check the cause of the disease and target treatment. Drugs should be used under the guidance of the doctor’s advice, avoid taking privately, so as to avoid adverse effects.