Whether or not pain still occurs 40 days after fibula internal fixation surgery is related to whether or not the patient develops osteofascial intercompartmental syndrome, infection, and soft tissue injury at the broken end of the fracture. Closed fibula fracture can be treated by incision reduction internal fixation, closed reduction intramedullary pin internal fixation, external fixation frame fixation and other methods. 40 days after fibula internal fixation surgery, if the recovery is good, usually does not cause pain, the following conditions can cause pain: 1. Osteofascial compartment syndrome: it is a complication after fibular internal fixation surgery, which may appear symptoms such as pale skin of the affected limb, elevated skin temperature, persistent severe pain (the pain is aggravated when the toe is stretched passively), swelling of the affected limb, sensory paralysis, and weakened or disappeared arterial pulsation. 2. Infection: redness, swelling and pain around the wound indicate infection. 3. Soft tissue injury around the fracture break. Surgical incision and pulling of the soft tissue can cause swelling and stimulation of the nociceptive nerve and trigger pain. Other reasons may also occur 40 days after fibula internal fixation surgery pain, when the pain is recommended to consult a doctor in time, clear cause of the disease and then give symptomatic treatment.