Ankle Fractures Justin Mullner – 8/27/09

Outline Anatomy and common ankle views Ottawa Ankle Rules Classifications (Weber, Lauge-Hansen) Biomechanics Named fractures The tibia and fibula have specific parts that make up the ankle: Medial malleolus: Inside part of the tibia Posterior malleolus: Back part of the tibia Lateral malleolus: End of the fibula Two joints are involved in ankle fractures: Ankle joint Syndesmosis: The joint between the tibia and fibula, which is held together by ligaments Multiple ligaments help make the ankle joint stable

LATERAL VIEW Standard radiographic examination of the ankle includes AP, lateral, and mortise views of the joint. Mortise view requires oblique examination at 20 to 30 degrees internal rotation and results in alignment of medial and lateral malleoli in the same plane. http://www.med-ed.virginia.edu/courses/rad/ext/8ankle/01anatomy.html Talus: Also called the ankle bone, the talus sits directly behind the navicular (medially)

AP VIEW MORTISE VIEW http://www.med-ed.virginia.edu/courses/rad/ext/8ankle/01anatomy.html

Lateral Ankle Ligaments Medial Ankle Ligaments CFL = Calcaneofibular ligament PTFL = Posterior talofibular ligament ATFL = Anterior talofibular ligament Deltoid ligament covers the medial ankle and is comprised of: posterior tibiotalar ligament tibiocalcaneal ligament tibionavicular ligament anterior tibiotalar ligament Peroneus Longus and Brevis Tendons run over the PTFL https://www.northcoastfootcare.com/footcare-info/foot-anatomy.html CFL = Calcaneofibular ligament PTFL = Posterior talofibular ligament ATFL = Anterior talofibular ligament Deltoid Ligament

Ottawa Ankle Rules Before introduction of the rules, all injured ankles were X-rayed but only 15% were positive for fracture The ankle is the most commonly injured weight bearing joint Unnecessary X-rays: costly, time consuming, and possible health risk Unnecessary X-rays: costly, time consuming, and health risk

Ottawa Ankle Rules X-rays are only required if there is bony pain in the malleolar zone AND any one of the following: 1 – Tenderness along the distal 6cm of the posterior edge of the tibia 2 – Tenderness along the distal 6cm of the posterior edge of the fibula 3 – Inability to bear weight immediately after injury and in the ER

Ottawa Ankle Rules http://www.gp-training.net/rheum/ottawa.htm

Classification Schemes Danis-Weber system Level of the fibular fracture in relationship to the ankle joint (A, B, C) Ideal for the primary care setting – allows you to classify the injury easily and guides treatment Lauge-Hansen system 2-word descriptors detailing position and motion of the foot each with 2-4 stages specifying exact locations of fractures More descriptive but very complicated i.e. pronation-abduction-stage 2 Supination-adduction supination-external rotation (eversion) Pronation-abduction pronation-eversion Pronation-dorsiflexion

Biomechanics Dorsiflexion Eversion Adduction Plantarflexion Inversion Abduction Supination = Abduction + inversion + plantarflexion triplanar Pronation = Adduction + eversion + dorsiflexion

Biomechanics Simple unidirectional forces can be involved in an ankle injury resulting in ligamentous damage and isolated fractures Multidirectional forces are usually involved making diagnosis a challenge

Biomechanics Lateral Complex Distal fibula Lateral facet of the talus Lateral ligaments of the ankle Subtalar joints Lateral complex injuries typically occur with inversion and supination The most common ankle injury Inversion ligamentous injuries of the ankle are the most commonly observed soft-tissue trauma in sports.

Biomechanics Anteroposterior (AP) radiograph (left) of ankle in 23-year-old woman shows medial displacement of talus relative to tibia: horizontal avulsion fracture through lateral malleolus and vertically oriented compression fracture through medial malleolus. Model on right shows mechanism of Weber type A ankle fracture: As talus undergoes inversion rotational injury, it applies avulsive pulling forces on lateral side of mortise and compressive pushing forces on medial side. Type A fractures are horizontal avulsion fractures found below the mortise. They are stable and amenable to treatment with closed reduction and casting unless accompanied by a displaced medial malleolus fracture. http://www.radiology.wisc.edu/people/schreibman/files/Schreibman_AnkleTrauma_ARRS'08.pdf Inversion force avulses the lateral malleolus and continued force causes oblique fracture of the distal tibia

Biomechanics Medial Complex Medial malleolus Medial facet of the talus Superficial/deep deltoid ligament Medial complex injuries typically occur from eversion and abduction Most unstable ankle fractures are the result of excessive external rotation of the talus with respect to the tibia. If the foot is supinated at the time of external rotation, an oblique fracture of the fibula ensues. If the foot is pronated at the time of external rotation, a mid- or high-fibular fracture results.

Biomechanics Anteroposterior (AP) radiograph (left) of ankle in 79-year-old woman shows lateral displacement of talus relative to tibia, horizontal avulsion fracture through medial malleolus, and obliquely vertically oriented compression fracture through distal fibula, below level of syndesmosis. Model on right shows mechanism of Weber type B ankle fracture. As talus undergoes eversion rotational injury, it applies avulsive pulling forces on medial malleolus and compressive pushing forces on fibula. Type B fracture is a spiral fibular fracture that starts at the level of the mortise. This type of fracture occurs secondary to external rotational forces. These fractures may be stable or unstable depending on ligamentous injury or associated fractures on the medial side. Eversion force avulses the distal medial malleolus (young/elderly) and continued force results in rupture of the syndesmosis or transverse fracture of the distal fibula

Biomechanics AP radiograph (left) of ankle in 30-year-old woman shows horizontal avulsion fracture through medial malleolus and obliquely vertically oriented compression fracture through distal fibula, above level of syndesmosis. Syndesmosis is disrupted and abnormally widened, with no overlap between tibia and fibula. Model on right shows mechanism of Weber type C ankle fracture. Mechanism of injury is same as Weber type B except compressive force extends through syndesmosis, tearing tibial fibular ligaments and distal IOM, with oblique fracture higher up on fibula. If compressive force extends proximally up length of IOM, fracturing through proximal fibula up near knee, then this is referred to as “Maisonneuve fracture” (next slide). Type C fracture is above the level of the mortise and disrupts the ligamentous attachment between the fibula and the tibia distal to the fracture. These fractures are unstable and require open reduction and internal fixation. Horizontal avulsion fracture through the medial malleolus and oblique-vertically oriented compression fracture through the distal fibula. The syndesmosis is disrupted and abnormally widened, with no overlap between tibia and fibula

MAISONNEUVE FRACTURE -Proximal half of fibula -Strong eversion -The more proximal the fracture, the more unstable the joint Fracture of the proximal half of the fibula. Results from strong eversion at the ankle joint. Disruption of the tibiofibular syndesmosis occurs as well as fracture of the medial malleolus or tearing of the tibiofibular ligament. A greater extent of damage is done to the interosseous membrane when the fracture is more proximal. http://www.med-ed.virginia.edu/courses/rad/ext/8ankle/01anatomy.html

TILLAUX FRACTURE Lateral margin avulsion of the distal tibia Abduction + External Rotation Typically occurs in adolescents after medial epiphyseal plate closes but before the lateral (18 month window) Tillaux Fracture external rotation force w/ stress placed on anterior tibiofibular ligament, causing avulsion of distal tibial epiphyseal plate anterolaterally;           - further lateral rotation causes displacement of fracture;     Look for a vertical fracture line extending from the distal articular surface upward to the lateral cortex of the tibia. Careful radiologic exam is critical for determining the neccesity of surgery. If there is greater than 2 mm lateral displacement of the fracture fragment or step-off of the distal articular surface, surgery is often required. Otherwise, conservative treatment is indicated. CT is most commonly the method of choice for this evaluation. http://www.med-ed.virginia.edu/courses/rad/ext/8ankle/01anatomy.html

TRIPLANE FRACTURE Twisting Injuries - adolescents 1 = vertical frxr thru the epiphysis TRIPLANE FRACTURE 2 = horizontal frxr thru the physis 3 = oblique frxr thru the metaphysis frx tends to occur in older children and young adolescents during an 18 month window, prior to physeal closure;           - lateral portion of epiphysis is the last to close leaving it vulnerable to injury; the fracture exists in the frontal, lateral, and transverse planes AKA = Marmor-Lynn occurs due to external rotation forces; http://www.radiology.wisc.edu/people/schreibman/files/Schreibman_AnkleTrauma_ARRS'08.pdf Twisting Injuries - adolescents

PILON FRACTURE Fractures of the tibial pilon are injuries than involve the ceiling or top of the ankle joint. These are distinguished from “ankle fractures” which involve the sides or malleoli at the ankle joint. Tibial pilon fractures are usually the result of high energy trauma. Typical mechanisms of injury are falls from height (for example, falls from a ladder, roof, or building), motor vehicle crashes, or motorcycle crashes. Sometimes they occur from other activities such as snow skiing. Pilon fractures refer to any tibial fracture that involves the distal articular plafond and are typically the result of an axial loading force TRAUMA!!

TRIMALLEOLAR FRACTURE This fracture may be caused by talar eversion and posterior displacement. The fracture is also known as a Henderson fracture. Can be caused by talar eversion and posterior displacement Also known as a Henderson fracture

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