INTRODUCTION	Section 2 of 10
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Background: Since the late 1980s, physicians throughout the world have been treating more ankle fractures each year. In the past 20 years, it appears that more ankles are fractured with seemingly minor trauma, in individuals older than 50 years, and producing more serious fracture combinations.

The emergency physician will regularly evaluate and treat ankle fractures. It is imperative for the emergency physician to understand the types of fractures a patient may suffer and to initiate appropriate treatment and stabilization measures. The emergency physician is also in a unique position to provide a fall risk assessment for those individuals who have gait disorders or difficulty with ambulation who are at risk to sustain a fall-related injury.

Ankle fractures refer to fractures of the distal tibia, distal fibula, talus, and calcaneus.

The ankle joint is actually composed of 2 joints: the true ankle joint and the subtalar joint.

The true ankle joint contains the tibia (medial wall), fibula (lateral wall), and the talus (the floor upon which the tibia and fibula rest). The true ankle joint allows dorsiflexion and plantar flexion or the "up and down" movement at the ankle. The toes and foot can be made to point toward the floor or toward the ceiling through the true ankle joint.

The subtalar joint consists of the talus and the calcaneus. The subtalar joint allows the foot to be inverted or everted, that is, the sole of the foot can be made to face inward (inverted) or face outward (everted) through the subtalar joint.

The mechanism of injury, morbidity, schedule for intervention (emergency surgery vs delayed surgery), immobilization, and rehabilitation must all be considered when the emergency physician is evaluating the true or subtalar ankle fractures.

Ankle injuries, including fractures, are commonly seen in the emergency department. It benefits the patient if these, and other questions, are addressed with the orthopedist, therapists, radiology staff, and emergency nurses.

During evaluation of ankle fractures, the mechanism of injury (eg, eversion, inversion, dorsiflexion, plantar flexion), associated injuries (eg, vascular, ligamentous, capsular, anterior tibiofibular ligament), the need for immobilization (eg, application of a splint) to prevent further injury and establish recovery, and the need for referral to a specialist for further treatment or evaluation (eg, additional immobilization, rehabilitation) are all important components of care.

Pathophysiology: The primary motion of the ankle at the true ankle joint (tibiotalar joint) is plantarflexion and dorsiflexion.

Inversion and eversion occur at the subtalar joint located between the talus and the calcaneus.

Excessive inversion stress is the most common cause of ankle injuries for 2 anatomic reasons. First, the medial malleolus is shorter than the lateral malleolus, thus allowing the talus to invert more than evert. Second, the deltoid ligament stabilizing the medial aspect of the ankle joint is a stronger support than the thinner lateral ligaments. The ankle is much more stable and resistant to eversion injury than inversion injury as a result; however, when eversion injury does occur, the individual often suffers substantial damage to bony and ligamentous supporting structures and loss of joint stability.

Transverse malleolar fractures usually represent an avulsion-type injury, while vertical malleolar fractures result from talar impaction.

Frequency:

• In the US: It is often quoted that of all the ankle injuries that undergo evaluation in the ED only 15% will be ankle fractures. However, the frequency of ankle fractures has been increasing for the past 20 years and the true incidence of ankle fractures requires updated study.

Mortality/Morbidity:

• Patients with unrecognized or undertreated open ankle fractures are at high risk for both local infection (including osteomyelitis) and sepsis. Gas gangrene is the most serious infectious complication and can be life threatening as well as limb threatening.

• Vascular supply to the ankle and foot may become compromised by development of a compartment syndrome or direct injury to blood vessels from bone fragments.

• Talus fractures, such as those that may occur in snowboarding fractures, can cause osteoarthritis and subtalar joint degeneration.

• The calcaneus is part of the subtalar joint. A calcaneal fracture will compromise inversion and eversion of the ankle. Surgical complications and prolonged rehabilitation are common with calcaneal fractures.

Race: No race predilection is noted.

Sex: The male-to-female ratio is 2:1, while women older than 40 years have a higher proportion of fracture-dislocations.

Age: Ankle fractures can occur at any age, and, each patient, whether a child or adult must be evaluated with an understanding of the unique evaluation and management requirements for each age.

• Pediatric ankle bones are susceptible to medial malleolar and transitional fractures of the distal tibia.

• Patients who are 50 years or older are sustaining ankle fractures of various types with increasing frequency. Kannus et al eloquently stated "the population at risk [for ankle fractures] is constantly expanding and will expand more rapidly in the near future."

• Ankle fractures are frequently observed in postmenopausal women, although ankle fracture may not be due to osteoporosis.

	CLINICAL	Section 3 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

History:

• Knowledge of the direction of torque force applied to the ankle and the foot's position at the time of injury helps predict the nature and severity of an ankle injury. While patients tend to recall the event, they often cannot depict the exact manner in which their injury occurred. Perhaps more important than the precise mechanism of ankle injury are the circumstances surrounding the injury, which may predict more serious trauma to other bones or organ systems.

• Document chronic medical conditions, especially the presence of diabetes, peripheral vascular disease, and metabolic bone disease, because this may affect exam findings and treatment plans.

• Establish history of prior trauma to the affected ankle because antecedent laxity, instability, or former radiographic abnormalities may be misinterpreted as an acute event.

• Inquire about medication usage that may provoke premature osteoporosis, such as corticosteroids, or drugs (eg, nonsteroidal anti-inflammatory drugs [NSAIDs]) that may mitigate the degree of swelling normally expected with fractures.

Physical: As an ankle fracture often presents with symptoms similar to those of an ankle sprain, complete a thorough examination of the involved extremity to avoid misdiagnosis and prevent unnecessary radiographs.

• Indicators suggesting fracture include gross deformity, swelling (especially perimalleolar), bony tenderness, discoloration, and ecchymosis. Inability to bear weight on the injured foot also indicates fracture.

• Inspect carefully, noting the presence of open wounds close to the injured ankle.

• Palpate for focal bony tenderness, especially along the medial and lateral malleoli and posterior aspect of the joint.

• Corroborate any visible deformity by gently manipulating the affected area.

• Assess passive and active range of motion of the ankle joint, noting limitations. During the immediate acute phase, most patients' ankles are too tender to cooperate with stress testing of the joint.

• Assess the neurovascular status of the foot and ankle. Compare findings to unaffected extremity.

• Check presence and quality of pulse of the posterior tibial artery. A hand-held Doppler can be useful to document arterial patency.

• Check presence and quality of pulse of dorsalis pedis artery. Note that the dorsalis pedis is congenitally absent in as many as 10-15% of the population.

• Document the time for capillary refill.

• Examine the ipsilateral knee and foot, particularly documenting the condition of the proximal fibula and proximal fifth metatarsal.

Causes: Two classification schemes, the Lauge-Hansen and Danis-Weber, currently are employed to help categorize ankle fractures. Derived from cadaver studies, the Lauge-Hansen system categorizes ankle fractures based on the position of the foot and the forces acting on it at the time of injury, while Danis-Weber relies on the level of fibular fracture.

• Lauge-Hansen classification: Position of the foot (eg, supination, pronation) is described first. Second, the deforming force is described as external rotation, abduction, or adduction. A definitive number of combinations exist, and the severity of the injury conforms to the amount of force applied in each direction. This classification does not include axial compression injuries.

• Supination-adduction class
  • Stage I - Transverse fracture of lateral malleolus

  • Stage II - Steep oblique fracture of medial malleolus

• Supination-external (eversion) rotation class
  • Stage I - Rupture of anterior tibiofibular ligaments

  • Stage II - Spiral fracture of distal fibula

  • Stage III - Disruption of posterior tibiofibular ligaments with or without avulsion of the posterior malleolus

  • Stage IV - Oblique fracture of medial malleolus

• Pronation-abduction class
  • Stage I - Transverse fracture of medial malleolus or torn deltoid ligament

  • Stage II - Disruption of posterior and anterior tibiofibular ligaments with or without avulsion of posterior malleolus

  • Stage III - Oblique fracture of distal fibula

• Pronation-external (eversion) rotation class
  • Stage I - Transverse fracture of medial malleolus or torn deltoid ligament

  • Stage II - Disruption of anterior tibiofibular ligament complex and interosseous membrane

  • Stage III - High fracture of fibula (above the joint)

  • Stage IV - Disruption of posterior tibiofibular ligament with or without avulsion of posterior malleolus

• Pronation-dorsiflexion class
  • Stage I - Fracture of the medial malleolus

  • Stage II - Fracture of the anterior lip of the tibial

  • Stage III - Fracture of the supramalleolar aspect of the fibula

  • Stage IV - Rupture of the posterior inferior tibiofibular ligament or fracture of the posterior malleolus

• Danis-Weber classification: These fractures are classified according to location of the fracture and appearance of the fibular component.

• Type A depicts a transverse fibular avulsion fracture, occasionally with an oblique fracture of the medial malleolus. These result from internal rotation and adduction.

• Type B describes an oblique fracture of the lateral malleolus with or without rupture of the tibiofibular syndesmosis and medial injury (either medial malleolus fracture or deltoid rupture). These result from external rotation.

• Type C designates a high fibular fracture with rupture of the tibiofibular ligament and transverse avulsion fracture of the medial malleolus. Usually syndesmotic injury is more extensive than in type B. These result from adduction or abduction with external rotation.

• Fracture eponyms

• Pilon fracture
  • A pilon fracture designates a fracture of the distal tibial metaphysis combined with disruption of the talar dome. This fracture originates from an axial loading mechanism in which the talus drives into the tibial plafond, such as when a patient involved in an auto accident compresses his foot on the floorboard to brace against injury. Skiers coming to an unexpected sudden stop and victims of free fall from heights also may sustain pilon fractures. Incidence of pilon fractures ranges from 1-10% of all tibial fractures.

  • Establish vascular and integument integrity. Perform a meticulous exam of the skin, because marked swelling and breaching of the integument frequently accompany these fractures. Skin sloughing is not uncommon. Subsequent edema, fracture blisters, and skin necrosis from the original injury may convert closed fractures to open injuries.

  • Associated injuries include spinal compression fractures, especially of L1, and ipsilateral or contralateral fractures of the os calcis, tibial plateau, pelvis, or acetabulum.

• Maisonneuve fracture
  • A Maisonneuve fracture is defined as a proximal fibular fracture coexisting with a medial malleolar fracture or disruption of the deltoid ligament. Maisonneuve fractures are associated with partial or complete disruption of the syndesmosis.

  • Treatment of Maisonneuve fractures depends on stability of the ankle mortise.

• Tillaux fracture
  • A Tillaux fracture describes a Salter-Harris (SH) type III injury of the anterolateral tibial epiphysis caused by extreme eversion and lateral rotation of the ankle. Incidence is highest in adolescents, usually those aged 12-14 years, because the fracture occurs after the medial aspect of the epiphyseal plate of the tibia closes but before the lateral aspect arrests.

  • Distinguish a Tillaux fracture from a triplane fracture. Triplane fracture is a combination of a SH II and III fracture and is more likely than a Tillaux fracture to require open reduction and internal fixation.

  • Bimalleolar fractures, termed Pott fractures, involve at least 2 elements of the ankle ring. These fractures should be considered unstable and require urgent orthopedic attention.

  • A trimalleolar, or Cotton, fracture involves the medial, lateral, and posterior malleoli. These fractures are considered unstable and require urgent orthopedic attention.

• Snowboarder's fracture
  • With the popularity of snowboarding in the late adolescent and young adult population, it is likely the emergency physician will come across a fracture of the lateral process of the talus, the so-called snowboarding ankle fracture.

  • A combination of dorsiflexion and inversion of the ankle produces the lateral talar fracture.

  • A high index of suspicion should be used in snowboarders who complain of lateral ankle pain with a normal-appearing ankle radiograph. Computed tomography imaging is often required to diagnose a talus fracture.