Fever after knee trauma may be local bleeding, hematoma absorption, fever, body temperature is low fever, local no obvious redness, swelling, infection manifestation, last 2-3 days natural return to normal, can be appropriate ice to relieve symptoms. It may be superficial skin infection or septic arthritis, osteomyelitis and other problems. Generally, the local redness and swelling are obvious, and the whole body is also accompanied by high fever and other symptoms of infection, which can be determined by the magnetic resonance of the knee joint, blood routine and other tests. After determining the condition, levofloxacin and other anti-infective treatment can be used, and localized cast immobilization and braking are necessary to help limit the inflammation, and surgical drainage is necessary for serious infections. Other may be trauma combined with gout and other diseases caused by fever, can be determined by uric acid test, treatment can choose febuxostat and other drugs to reduce uric acid.