Detecting and Treating Common Foot and Ankle Fractures: Part 1: The Ankle and Hindfoot
David B. Thordarson, MDTHE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 9 - SEPTEMBER 96
This is the first of two articles on fractures of the foot and ankle. The second article, on midfoot and forefoot fractures, will appear in a subsequent issue.
In Brief: Some of the most common and potentially serious ankle and hindfoot fractures seen in a primary care sports medicine practice are fractures of the tibial plafond, malleolus, calcaneus, and talus (including osteochondral lesions). Making a careful physical exam to detect for sites of tenderness and ordering the appropriate diagnostic images—usually plain films—are important in pinpointing the diagnosis, but some injuries, like Maisonneuve fractures, can be difficult to detect. Certain injuries, like many fractures of the lateral process of the talus, can be managed conservatively with casting, but severe or displaced fractures usually require surgery. Rehabilitation typically focuses on rest and proper strengthening and stretching exercises.
Fractures of the foot and ankle immediately impair a recreational or elite athlete's ability to perform competitively in virtually any sporting activity. Fractures of the ankle and hindfoot usually occur acutely in a traumatic episode; chronic injuries like stress fractures are more likely in the midfoot and forefoot. Some of the more common fractures heal well with nonoperative care and some require surgical treatment, so an accurate diagnosis is essential.
Ankle fractures have been classified in various ways. An important initial distinction is whether a fracture is of a malleolus, or is a much more severe tibial plafond (pilon) intra-articular impaction fracture.
Tibial plafond. Tibial plafond fractures (figure 1) generally result from a high-energy axial load, as can occur in a fall from a height or a motor vehicle accident. Patients experience immediate pain and cannot walk. On exam, they generally have significant swelling with or without deformity.
These fractures—in contrast to malleolus fractures—involve the weight-bearing surface of the plafond and generally require open reduction and internal fixation. Results are frequently poor despite operative intervention (1). Fortunately, tibial plafond fractures are uncommon in athletes.
Malleolus. Fractures involving the malleolus are a much more common type of ankle fracture. They can involve the lateral or medial malleolus, or both, and they usually result from an external rotation injury to the ankle (figure 2). Ligament damage is typical, generally of the deltoid ligament and of the anterior and posterior tibiofibular ligaments. Patients feel immediate pain and have difficulty walking or cannot walk. Moderate-to-severe swelling and bony tenderness exist over the fracture site(s), with or without a visible deformity.
Malleolus fractures are typically classified by one of two systems. The Lauge-Hansen fracture classification relies on the position of the foot at the time of injury and includes four types:
The Danis-Weber system is based on the level of the fibular fracture relative to the ankle joint (3). It includes type A, fracture below the ankle joint; type B, fracture at the level of the joint, in which the tibiofibular ligaments are most likely intact; and type C, which occurs above the joint and disrupts the syndesmotic ligaments. In both the Lauge-Hansen and Danis-Weber classifications, a fracture higher on the fibula indicates more instability and, therefore, a greater likelihood of surgical intervention.
The initial treatment for all displaced malleolus fractures is closed reduction and casting followed by ice and elevation. If an anatomic reduction is obtained, these fractures can be managed with a cast. However, postreduction radiographs must show that the joint space is symmetric on a mortise view (figure 3) because even 1 to 2 mm of displacement of the talus within the mortise can cause dramatic changes in the contact area and pressures within the ankle. One study (4) demonstrated a 40% decrease in contact area with a 1-mm lateral shift of the talus.
Because of this potential for change in the contact area and pressure in the ankle with an intra-articular fracture, surgeons recommend open reduction and internal fixation of persistently displaced malleolus fractures to guarantee an anatomic reduction. An added benefit of operative treatment in an athlete is a more aggressive, early rehabilitation. Range-of-motion exercises can be started after wound healing, but compliance with non-weight bearing must be emphasized.
Most patients with a malleolus fracture require 6 weeks of immobilization. Patients with a displaced ankle fracture that has undergone successful closed reduction will typically require 2 to 4 weeks in a long-leg cast and then an additional 2 to 4 weeks in a short-leg nonwalking cast. Patients with an initially nondisplaced fracture or who were treated surgically will generally require 4 weeks of non-weight bearing in a short-leg cast or removable walking boot, followed by 2 weeks in a walking cast or boot. The removable boot will allow for earlier range-of-motion exercises.
In patients treated nonoperatively, follow-up radiographs must be obtained weekly for the first 2 to 3 weeks following injury to rule out fracture displacement. Following fracture healing, patients can begin physical therapy for range-of-motion and strengthening exercises. Most patients who sustain a malleolus fracture will miss at least 3 months from most sports, and frequently 6 months or more from cutting-type sports.
Maisonneuve. A Maisonneuve fracture—an external rotation injury of the ankle with an associated fracture of the proximal third of the fibula—is a serious injury that can have deceptively minor radiographic findings. Although less common than other types of ankle fractures, it is often misdiagnosed and can result in long-term disability. The typical mechanism and presentation are external rotation of the foot and medial ankle pain. On examination, the patient will have tenderness over the deltoid ligament and over the fracture site on the proximal fibula. Any patient who has proximal fibular tenderness after a twisting injury to the ankle should have radiographs taken of both the ankle and the tibia and fibula.
Radiographs of the ankle generally reveal no fracture or only a small avulsion injury of the medial malleolus with variable widening of the space between the tibia and fibula (figure 4a). A radiograph of the whole tibia and fibula, however, will demonstrate a high fibula fracture (figure 4b). These patients require open reduction and internal fixation with one or two screws placed between the distal fibula and tibia to maintain the bones' normal relationship while ligament healing occurs. The screws are generally removed 8 to 12 weeks after surgery.
Like tibial plafond fractures, calcaneus fractures occur most commonly after high-energy axial loads. They can also stem from an avulsion of the Achilles tendon. Approximately 75% of calcaneus fractures extend into the subtalar joint (5). Both high-energy fractures and avulsion are relatively uncommon in athletes because of the mechanism of injury, but either can result in permanent disability. Following a fracture, patients have severe heel pain and cannot walk. They have moderate-to-severe hindfoot swelling and tenderness on exam.
Intra-articular fractures that result from an axial load need to be carefully assessed for displacement on lateral and axial radiographs (figure 5); any displacement warrants a computed tomography (CT) scan. Initial treatment for displaced and nondisplaced intra-articular fractures includes immobilization in a bulky dressing and splint, with ice and elevation to control edema. Most displaced fractures are managed operatively, but these patients typically experience residual stiffness of their subtalar joint that will adversely affect future athletic performance. For nondisplaced extra-articular calcaneus fractures, patients wear a short-leg cast or walking boot for about 6 weeks.
Avulsion fractures occur during a violent contraction of the gastrocnemius and soleus. If not displaced or if minimally displaced, they can be managed in a plantar-flexed short-leg cast for 6 weeks followed by physical therapy involving stretching. Most of these fractures, however, are significantly displaced and frequently require immediate surgery to repair the fracture and relieve the pressure on the skin overlying the bony fragment.
Talus fractures typically involve either the talar neck or lateral process, or an osteochondral fracture of the talar dome.
Talar neck. Although talar neck fractures (figure 6) are relatively uncommon and represent high-energy injuries involving hyperdorsiflexion of the ankle, they deserve mention because of the potential devastating complication of avascular necrosis of the talus. A typical mechanism of injury is a motor vehicle accident in which the ankle is hyperdorsiflexed by the brake pedal. Patients experience severe hindfoot pain and moderate-to-severe edema, tenderness, and ecchymosis. The body of the talus may be palpable in the posteromedial ankle area.
Displaced talar neck fractures are true surgical emergencies. The fracture must be reduced immediately to minimize the risk of avascular necrosis or skin slough. The talus has limited vascularization; most of its blood supply enters the neck via an anastomotic sling and flows posteriorly. A fracture, therefore, disrupts the intraosseous portion of the blood supply, and the greater the displacement, the greater the disruption of the blood supply and likelihood of necrosis. Avascular necrosis may lead to collapse of the body of the talus, resulting in arthritic changes that necessitate ankle fusion. Even without avascular necrosis, many patients develop a significant degree of subtalar arthrosis or arthritis, which leads to residual hindfoot stiffness and pain. Treatment for patients who have a nondisplaced talar neck fracture typically involves a short-leg nonwalking cast for 6 to 8 weeks followed by range-of-motion exercises.
Lateral process. Although fractures of the lateral process of the talus are relatively uncommon, they can be a source of chronic lateral ankle pain following an inversion injury. The typical mechanism of injury is acute hyperdorsiflexion with inversion (5). The patient will experience lateral ankle pain and have edema and tenderness in this area. Radiographs reveal a variable-sized fragment of the lateral process along the inferior aspect of the talus. This defect is most easily identified on a lateral radiograph.
Nondisplaced fractures require 6 weeks in a short-leg cast. Large displaced fragments (generally greater than 1 cm in diameter) should be treated with open reduction and internal fixation. Small displaced fragments can be treated symptomatically and can be excised if symptoms persist.
Osteochondral injury. A more common talus injury in sports is an osteochondral fracture of the dome of the talus that results from an inversion injury. A related, chronic condition probably caused by repetitive trauma is osteochondritis dissecans (OCD). A typical posttraumatic osteochondral fracture or an OCD lesion occurs in the anterolateral aspect of the talar dome. It is postulated that the corner of the talus fractures as the dome rotates laterally through the mortise (5).
Patients who sustain an acute osteochondral fracture have pain with weight bearing. If the fragment displaces, they will experience locking or clicking. On exam, they have tenderness over the lateral aspect of the talar dome. Radiographs typically show a small flake of bone off the lateral dome of the talus. Occasionally, plain radiographs will be negative, and magnetic resonance imaging can establish the diagnosis and define the extent of the lesion.
An OCD lesion may appear as a cyst or loose piece of bone in either the anterolateral or posteromedial dome of the talus (figure 7). Patients report a gradual onset of pain that is generally activity related and, if the fragment displaces, mechanical symptoms such as locking. If the fragment is nondisplaced and follows an acute injury, the patient can be treated with a short-leg nonwalking cast for 6 weeks followed by range-of-motion exercises. In more chronic cases, or if the fragment is displaced, the fragment can be removed arthroscopically and the bony defect can be drilled to encourage fibrocartilage formation. These patients should avoid weight bearing for 6 weeks while fibrocartilage is forming, but they can do range-of-motion exercises at this time.
Although fractures of the foot and ankle can be a source of significant disability and require surgery, many ankle and hindfoot fractures sustained in athletic activities are amenable to nonoperative treatment. Primary care sports medicine physicians, therefore, must not only make astute diagnoses, they must be well-versed in rehabilitation strategies for both conservative and postoperative treatment.
Dr Thordarson is an assistant professor of orthopedic surgery and the chief of Foot and Ankle Trauma and Reconstructive Surgery in the Department of Orthopaedic Surgery at the University of Southern California in Los Angeles. Address correspondence to David B. Thordarson, MD, 1200 N State St, GNH 3900, Los Angeles, CA 90033.