Practice Essentials
The ankle is composed of 2 joints: the true ankle joint and the subtalar joint. Ankle fractures refer to fractures of the distal tibia, distal fibula, talus, and calcaneus. The true ankle joint contains the tibia (medial wall), fibula (lateral wall), and talus (the floor upon which the tibia and fibula rest) and 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 outward (everted) through the subtalar joint.
Ankle fractures are the most common fractures of the lower limbs found in emergency services. Approximately 53% of these fractures are unstable and are treated surgically. [1] All patients with ankle injury should be evaluated for extensive and serious trauma depending on the circumstances. Chronic medical conditions, such as diabetes, peripheral vascular disease, and metabolic bone disease, may affect examination findings and treatment plans.
During evaluation of ankle fracture, important components of care include mechanism of injury (eg, eversion, inversion, dorsiflexion, plantar flexion), associated injuries (eg, vascular, ligamentous, capsular), need for immobilization (eg, application of a splint), and need for referral to a specialist for further treatment or evaluation (eg, additional immobilization, surgery, rehabilitation). Patients with ankle injury must be evaluated for further trauma.
Because a patient with 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 suggests a fracture.
Multiple classification schemes are used to classify ankle fractures. Emergency medicine physicians usually label ankle fractures according to the number of fractures in the ankle (unimalleolar, bimalleolar, trimalleolar). [2]
Routinely obtaining radiographs following an ankle injury is not cost-effective, because fewer than 15% of affected patients have a fracture. Patients without fractures are identified reliably on physical examination. Diagnostic guidelines for suspected ankle fracture are available from the American College of Radiology (ACR) Appropriateness Criteria. [3] The Ottawa Ankle Rules have been developed to predict the necessity of radiographs in acute ankle injuries, with the goal of protecting patients from unnecessary radiation exposure. [4]
For an isolated ankle injury, confirm the neurovascular status of the concerned limb, manage pain, and prevent further damage.
If the neurovascular status of the extremity is compromised, the fracture should be reduced as soon as possible and reduction should be maintained during the healing period with a cast, an external fixator, or open reduction internal fixation (ORIF). Unless neurovascular compromise is noted, reduction is best deferred to the orthopedic consultant when an unstable ankle fracture is diagnosed.
Oral analgesics should be used liberally as long as they do not interfere with other medication or the patient's ability to ambulate. The emergency physician might consider prescribing a narcotic.
Admission criteria include open fracture, unstable fracture requiring urgent operative stabilization, and the presence of or potential for neurovascular compromise (eg severely comminuted pilon fracture causing a compartment syndrome).
Pathophysiology
The primary motion of the ankle at the true ankle joint (tibiotalar joint) consists of plantarflexion and dorsiflexion. Inversion and eversion occur at the subtalar joint.
Excessive inversion stress is the most common cause of ankle injuriy 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 is offered by the thinner lateral ligaments. As a result, the ankle is more stable and is more resistant to eversion injury than inversion injury. However, when eversion injury occurs, bony and ligamentous supporting structures undergo substantial damage, and loss of joint stability is noted.
Posterior malleolar fractures are usually associated with other fractures and/or with 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.
Epidemiology
Ankle fractures (AFs) are the most common fractures of the lower limbs found in emergency services. Approximately 53% of these fractures are unstable and are treated surgically. [1]
Nationwide epidemiologic data regarding ankle fractures are scarce. Such information is important toward better quantifying the mortality associated with such injuries, as well as the financial impact and the implementation of preventive measures. Findings show that an estimated total of 673,214 ankle fractures occurred during a 5-year period, with an incidence rate of 4.22/10,000 person-years. The mean age of patients with an ankle fracture was 37 ± 22.86 (SD) years; 23.5% of ankle fractures occurred in patients aged 10-19 years (7.56/10,000 person-years). In addition, 44% of ankle fractures occurred in men (3.81/10,000 person-years), whereas 56% occurred in women (4.63/10,000 person-years). [5]
Data on race/ethnicity were available for 71% of patients, with incidence rates of 2.85/10,000 person-years for whites, 3.01/10,000 person-years for blacks, and 4.08/10,000 person-years for others. The most common mechanism of injury was falls (54.83%), followed by sports (20.76%), exercise (16.84%), jumping (4.42%), trauma (2.84%), and other (0.30%). [5]
The highest incidence of ankle fracture in men occurred in the 10- to 19-year age group, but women were more commonly affected in all other age groups. [5]
Mortality/Morbidity
Patients with unrecognized or undertreated open ankle fracture are at high risk of infection, including local infection, osteomyelitis, and sepsis. Gas gangrene, the most serious infectious complication, can be both limb and life threatening.
Vascular supply to the ankle and foot may become compromised by development of a compartment syndrome or by direct injury to blood vessels from bone fragments.
Talar fractures, which commonly occur in snowboarding trauma, can cause osteoarthritis and subtalar joint degeneration.
Calcaneal fractures may compromise inversion and eversion of the ankle. Surgical complications and prolonged rehabilitation are common.
Older patients with ankle fracture experience more long-term complications than younger patients.
Pediatric ankle fractures are common and have unique fracture characteristics because of the presence of distal tibial and fibular physes. When displaced (>3 mm widening of the physis or >2 mm intra-articular gap/step-off), these fractures are typically treated with anatomic reduction internal fixation (ORIF). Computed tomography is recommended for preoperative evaluation and surgical planning for intra-articular fractures. These fractures in younger children, with substantial growth remaining, should be followed closely to monitor for any growth disturbance. [6]
Prognosis
The prognosis for ankle fracture can be improved with prompt, accurate diagnosis and appropriate treatment and referral. Complex open fractures with substantial soft tissue damage have a worse prognosis than isolated closed ankle fractures. Isolated, nondisplaced lateral malleolus fracture, the most common ankle fracture, has a favorable prognosis and heals unremarkably.
Aggressive rehabilitation helps reduce the majority of morbidity associated with ankle fracture. Limitations in functionality and physical capacity represent the main threats to health-related quality of life for patients with surgically treated AFs. [1]
Delayed access to care for patients with ankle fracture may increase the risk of complications, particularly if surgical management is warranted. An institutional retrospective study found that average time from injury to surgery was 8.3 days and 16.1 days for privately insured and Medicaid patients, respectively (P< 0.001). Patients enrolled in Medicaid have significantly delayed access to care compared to those with private insurance. For patients with ankle fracture, this is a critical healing time, and delayed care may result in increased costs, increased utilization of healthcare resources, higher complication rates, and poorer patient outcomes. [7]
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Maisonneuve injury. Mortise view shows transverse fracture of the medial malleolus and widening of the tibiofibular syndesmosis without a fracture of the fibula. This injury is suggestive of a proximal fibula fracture (Maisonneuve fracture).
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Pilon fracture in a 35-year-old man who fell 20 ft. Anteroposterior radiograph shows at least 2 fracture lines extending to the articular surface (plafond) of the tibia.
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A 13-year-old girl with triplane fracture. Anteroposterior radiograph shows a sagittal component through the distal tibia epiphysis.
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An 11-year-old girl with juvenile Tillaux fracture. Mortise view shows fracture involving the lateral portion of tibial epiphysis.
