The AO typing after an ankle fracture is based on the relationship between the height of the ankle fracture and the inferior tibiofibular ligament union. an injury below the level of the tibiofibular union is called type A, a fibular fracture at the inferior tibiofibular union is type B, and an injury above the inferior tibiofibular is called type C. AO classifies ankle fractures into three types, ABC, and emphasizes the role of the external ankle without addressing the internal structures of the ankle joint. After a patient has an ankle fracture, limb specific treatment is taken according to the AO classification, like a simple type A can be done with internal fixation of the fibula. In the case of type C, the lower tibiofibular ligament staple must be done to alleviate future damage to the ankle ligaments.