Malleolar fractures

The ankle is a joint composed of three different bones, the tibia, the fibula, and the talus. The lower parts of the tibia and fibula articulate together to form the “ankle mortice”, a structure that contains the talus and allows joint stability and mobility. The ankle presents three malleoli (bone protuberances) which are located laterally (on the fibula, lateral malleolus), medially (on the tibia, medial malleolus), and posteriorly (on the tibia, posterior malleolus) to the ankle joint. The bones that shape the ankle are connected between each other and other structures by a series of ligaments that have the function of supporting optimal stability and biomechanics of the joint. Being the ankle joint constituted of different structures, ankle fractures can affect several bones and can be caused by significantly different injury mechanisms. When considering malleolar fractures, impact or twist injuries are the main mechanisms. Twist injuries happen when a rotational force, that is applied to the ankle, leads to its fracture, typically reported during sports activities or when tripping. On the other hand, impact injuries are caused by a high-energy collision with an external body, such as during a motor vehicle accident, a heavy object falling on the ankle, or when landing from a fall. Despite not being as common, low-energy impact injuries can be reported too, especially in older populations, or in subjects affected by specific conditions that make the bone more fragile (e.g.: osteoporosis). Malleolar fractures are typically classified based on the number of ruptured malleoli in a) isolated medial malleolus fracture; b) isolated lateral malleolus fracture; c) isolated posterior malleolus fracture; d) bimalleolar fracture (two malleoli are involved); and e) trimalleolar fracture (all the malleoli have been damaged). Injured patients typically experience high levels of pain, swelling, bruises, decreased function (e.g.: moving the ankle, walking, standing, etc.) and potentially ankle deformity depending on the extent of the injury.