Tendon tear is difficult to heal itself because of its special position. In addition, hyperglycemia in diabetic patients will also affect wound healing. After a long time, infection will occur and eventually develop into diabetic gangrene. Yuan Minqin, who treats diabetic foot, once said that it is useless to take injections to diminish inflammation and lower blood sugar. It is necessary to open the sutured wound, clean up the necrotic skin, muscles and blood vessels, reduce the load of germs, and help control infection. In the later stage, a traditional Chinese medicine ointment with the function of removing putrefaction and promoting granulation can be applied externally to the wound surface, and the curative effect can reach the focus. It is suggested that this situation should be treated in a local specialist as soon as possible to avoid the situation getting worse.