Knee fever and swelling, generally common clinical causes are mainly the following conditions: a. pus accumulation in the joint cavity, mainly due to acute purulent infection caused by the patient after trauma superficial tissue bacteria, along the wound surface infiltration into the joint cavity. Patients may experience fever and swelling of the knee. At this time, ultrasound examination of the knee joint can be improved to clarify the nature of the lesion and then perform pus extraction and flushing of the knee joint and strengthen local anti-infection treatment of the skin. After the local inflammation is controlled, the fever and swelling of the knee can be gradually relieved. Second, allergic patients in contact with pollen, dust and other allergens, the limbs will appear more obvious allergic reaction, the knee can appear local skin redness, swelling, fever, accompanied by maculopapular rash-like formation. At this time, patients can be treated with anti-allergic drugs such as external rubbing of glyburide lotion, oral loratadine, and intravenous application of dexamethasone. After the metabolic inflammatory reaction in the body is controlled, the symptoms of fever and swelling in the knee can be relieved by itself.