The possible causes of knee pain and fever in junior high school students include congenital developmental deformity, bursitis, and tibial tuberosity chondritis. 1. Meniscus congenital developmental deformity: due to the existence of some junior high school students congenital developmental deformity of the meniscus, such as discoid meniscus. Therefore, it is easy to cause meniscus tear and damage under the action of slight external force, resulting in more serious pain and fever in the knee. 2. Synovitis: junior high school students are more active, may be with the patient for a long time strenuous activities, such as playing football or running, resulting in local strain, triggered by synovitis. Synovial tissue appears aseptic inflammation, resulting in knee pain, swelling and joint effusion. At this time, touching the local skin temperature, the phenomenon of fever will appear. 3. Tibial tuberosity osteochondritis: It may be caused by tibial tuberosity osteochondritis, which is more common in junior students. Because the tibial tuberosity is still in the state of incomplete development, if the patient has high intensity sports, such as kicking, high jumping, kicking a ball, etc., it may cause local avulsion, resulting in acute injury to the tibial tuberosity, resulting in aseptic inflammatory reaction, accompanied by the phenomenon of fever. Junior high school students with knee pain and fever may also have other causes, it is recommended to go to the regular hospital in time to improve the relevant examination, clear the cause of the disease, under the guidance of the doctor for targeted treatment or treatment.