Yesterday, we performed an arthroscopy and joint cavity cleaning for a patient who was diagnosed with “septic arthritis” in the left knee and given a month of “anti-infection” treatment at an outside hospital. The patient did not dare to actively flex and extend the knee joint before the operation, but after the operation, the symptoms were significantly relieved and the patient is now moving the knee joint. Gout has a high incidence in Qingdao. If there is sudden redness, swelling and heat pain in the metatarsophalangeal joint of the bunions or knee joint, the possibility of gout should be considered.