The ankle joint is the largest weight-bearing flexor joint in the body, with a maximum force of about five times the body weight. Injuries to the ankle are most often associated with external ankle fractures and tibiofibular joint ligament injuries. Harper’s retrospective analysis of 42 cases of complete rupture of the deltoid ligament confirmed this view, and found that excessive ankle valgus can also cause simple deltoid ligament injury. The mechanisms of deltoid ligament injury include anterior-abduction, anterior-abduction and posterior-abduction of the ankle (the Lauge-Hanson subtype). As with other fractures, ankle fractures can be classified as stable or unstable fractures. Stable fractures are incomplete fractures or complete fractures that are not easily re-displaced after external fixation, and most of the long-term functions of the ankle joint are unaffected after the fracture and can withstand the normal range of stresses. The medial structures, especially whether the deltoid ligament is damaged or not, are the key to determine the stability of the fracture. Therefore, it is necessary to repair the deltoid ligament intraoperatively when the ankle fracture is accompanied by injury to the medial structures.