Left ankle avulsion fracture pain on the lower left side of the ankle may be caused by the fracture did not heal, articular cartilage damage, inflammatory reaction and so on. 1. The fracture has not healed: left ankle avulsion fracture pain on the lower side of the left ankle may be the fracture has not completely healed. At this time, there will be irritation to the broken end of the fracture when walking, and the broken end will have an effect on the periosteal nerve fiber, and there will be pain when walking. 2. Articular cartilage damage: when there is an avulsion fracture of the left lateral ankle, it can involve the articular cartilage and lead to cartilage damage. As it takes a long time for cartilage to repair and heal after fixation, and the healing ability is generally poor when cartilage is severely damaged, getting out of bed early after fracture will wear and irritate the cartilage, and pain will occur at this time. 3. Inflammatory reaction: walking on the ground in the early postoperative period will cause inflammatory reaction at the fracture end, and the inflammatory mediators will stimulate the nerve endings and produce pain symptoms. It is recommended that when this symptom occurs, you should go to the hospital for examination and standardized treatment under the guidance of the physician. During the healing period, pay attention to rest and avoid strenuous exercise to avoid discomfort.