The tibia at the ankle does not form an external rotation on its own, but often combines with the fibula to form external rotation symptoms. External rotation of the tibia and fibula in the ankle may be caused by skeletal dysplasia, trauma, or an imbalance in muscle strength. 1. Skeletal dysplasia: Congenital tibial dysplasia will cause the tibia to rotate, and at the same time, with the pulling of soft tissues such as muscles and ligaments, it will cause external rotation of tibiofibular bone of ankle. 2. Trauma: The tibia can be fractured when it is hit or pulled by external force, if the fracture is not repositioned or poorly repositioned, it will lead to external rotation of the tibia and fibula. 3. Muscle imbalance: Incorrect sports posture or standing for a long time will affect the tibiofibular muscles, causing an imbalance in the development of the muscles on both sides of the tibiofibular bone, which will lead to external rotation of the tibiofibular bone. In order to clarify the cause of tibiofibular external rotation of the ankle, it is recommended to visit the orthopedic department of the hospital in time and have a professional examination.