Swelling after one month of metatarsal fracture may be caused by poor local blood circulation, local infection and soft tissue adhesion. 1. Poor local blood return: If the fracture is more serious, it may damage the blood circulation of the traumatized area more seriously, thus leading to poor blood return, so there may still be swelling for a month. 2. Localized infection: If the patient has localized infection during the healing process, which in turn triggers an inflammatory reaction, it may also lead to swelling one month after the fracture. 3. Soft tissue adhesion: If the patient has soft tissue injury at the same time as the fracture, soft tissue adhesion and scarring may occur during the recovery process, resulting in swelling one month after the fracture. It is recommended that patients go to the hospital for a timely review, and under the guidance of professional doctors, active treatment.