eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics

Fracture, Ankle

Author: Kara Iskyan, MD, Staff Physician, Departments of Internal Medicine and Emergency Medicine, Allegheny General Hospital
Coauthor(s): Andrew A Aronson, MD, Assistant Professor of Emergency Medicine, Drexel University School of Medicine; Consulting Staff, Department of Emergency Medicine, Allegheny General Hospital
Contributor Information and Disclosures

Updated: Jul 15, 2008

Introduction

Background

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

The ankle joint is 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 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 of the ankle. The foot can be made to point toward the floor or toward the ceiling via 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.

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

For more information on fractures, see Medscape’s Fracture Resource Center.

For related CME activities, see CME - Calcium Supplementation May Reduce Fracture Risk and CME - More Evidence of Increased Fractures With Thiazolidinediones.

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.

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, allowing the talus to invert more than evert. Second, the deltoid ligament stabilizing the medial aspect of the ankle joint offers stronger support than the thinner lateral ligaments. As a result, the ankle is more stable and resistant to eversion injury than inversion injury. However, when eversion injury occurs, there is often substantial damage to bony and ligamentous supporting structures and loss of joint stability.

Posterior malleolar fractures are usually associated with other fractures and/or ligamentous disruption. They are commonly associated with fibular fractures and are often unstable.

Transverse malleolar fractures usually represent an avulsion-type injury. 

Vertical malleolar fractures result from talar impaction.

Frequency

United States

Of all the ankle injuries evaluated in the ED, only 15% are ankle fractures. The frequency of ankle fractures has been increasing for the past 20 years, and the rate is approximately 187 in 100,000 person-years.

Mortality/Morbidity

• Patients with unrecognized or undertreated open ankle fractures are at high risk of infection including local infection, osteomyelitis, and sepsis. Gas gangrene is the most serious infectious complication. It can be both limb and life 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, those commonly occurring in snowboarding trauma, can cause osteoarthritis and subtalar joint degeneration.
• A calcaneal fracture may compromise inversion and eversion of the ankle. Surgical complications and prolonged rehabilitation are common with calcaneal fractures.
• Older patients with ankle fractures experience more long-term complications than younger patients.

Race

No race predilection is noted.

Sex

The male-to-female ratio is 2:1. Most patients younger than 50 years are male, while most older than 50 years are female.

Age

• Pediatric ankle bones are susceptible to medial malleolar and transitional fractures of the distal tibia.
• As the population ages, ankle fractures are becoming more common. An increase in fall risk and osteoporosis are risk factors.

Clinical

History

• All injured patients should be evaluated for more extensive and serious trauma depending on the circumstances.
• Knowledge of the trauma, such as the direction of torque force applied to the ankle and the foot's position, helps predict the nature and severity of an ankle injury. Although patients tend to recall the event, they often cannot depict the exact manner in which their injury occurred.
• History of prior trauma to the affected ankle may cause antecedent laxity, instability, or radiographic abnormalities misinterpreted as an acute event.
• Chronic medical condition, such as diabetes, peripheral vascular disease, and metabolic bone disease, may affect examination findings and treatment plans.
• Chronic medication use is an important part of the history and has implications for management. For example, long-term use of corticosteroids may provoke premature osteoporosis, whereas nonsteroidal anti-inflammatory drugs (NSAIDs) may mitigate the degree of swelling normally expected with fractures.

Physical

Because an ankle fracture often presents with symptoms similar to those of an ankle sprain, a complete and thorough examination of the involved extremity is needed 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 a fracture.
• Corroborate any visible deformity by gently manipulating the affected area.
• Inspect carefully for the presence of open wounds close to the injured ankle.
• Assess the neurovascular status of the foot and ankle. Compare findings to the 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.
• Palpate for focal bony tenderness, especially along the medial and lateral malleoli and posterior aspect of the joint. If possible, palpate the most tender area last.
• 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.
• Examine the ipsilateral knee and foot, particularly documenting the condition of the proximal fibula and proximal fifth metatarsal.

Causes

• Multiple classification schemes are used for ankle fractures. 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 the Danis-Weber system relies on the level of fibular fracture. Neither classification scheme has been proven to be prognostic, so emergency medicine physicians usually label ankle fractures according to the number of fractures in the ankle (unimalleolar, bimalleolar, trimalleolar).
• Danis-Weber classification: These fractures are classified according to location of the fracture and appearance of the fibular component. To some degree, Weber classification correlates with need for operative stabilization. Orthopedic surgeons frequently use this classification system. 
  • Type A depicts a transverse fibular avulsion fracture, occasionally with an oblique fracture of the medial malleolus. These result from internal rotation and adduction. These are usually stable fractures.
  • 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. These may be unstable.
  • 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. These are usually unstable and require operative repair.
• Fracture eponyms
  • Pilon fracture
    • A pilon fracture designates a fracture of the distal tibial metaphysis combined with disruption of the talar dome. An axial loading mechanism drives the talus into the tibial plafond (the distal articular surface of the tibia). A common method of trauma is a foot braced against a floorboard in an auto collision. 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. Pilon fractures are often open. Skin sloughing is not uncommon. Subsequent edema, fracture blisters, and skin necrosis from the original injury may convert closed fractures to open injuries.
    • Depending on the trauma, associated injuries include spinal compression fractures (especially of L1) and ipsilateral or contralateral fractures of the os calcis, tibial plateau, pelvis, or acetabulum.
    • As pilon fractures are often comminuted and open, there is often significant long-term disability. 
  • 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.
  • Pott fracture: 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.
  • Cotton fracture: 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.

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