Ankle fracture
Fracture of the ankle joint is among the more common fractures in adults, comprising 10% of all fractures.13,14 The ankle joint is defined as the junction of 3 bony structures: (1) the distal ends of the tibia and fibula and (2) the trochlea of the talus, all stabilized by (3) the collateral ligament complex. Appropriate diagnosis and timely intervention are needed to prevent long-term posttraumatic joint degeneration.
Presentation, examination, and imaging. In addition to difficulty bearing (or inability to bear) weight, patients with suspected ankle fracture can present with tenderness or pain, swelling (generally, the more severe the injury, the more severe the swelling, although this finding is time-dependent), and ecchymosis. However, distinguishing fracture from a ligamentous injury is often difficult by physical examination alone; the evidence-based Ottawa Ankle Rules can guide determination of the need for radiographic imaging, although this tool is less reliable in certain patient populations (TABLE15-17).13,15-17
Management. A widely used classification system for guiding ankle fracture management is the Danis-Weber classification (FIGURE 2). In this scheme, type A fractures (distal to the level of the tibial plafond) are managed with ankle stabilization bracing without immobilization. Nondisplaced type B and C fractures (at the level of the tibial plafond and proximal to it, respectively) should be treated with 6 weeks of immobilization in a walking boot; close follow-up within 1 week of injury is recommended to ensure that no displacement of fragments has occurred. Type B and C fractures need to be followed until bony union is achieved. If there is radiologic evidence of a fracture line after 3 months, referral to an orthopedic surgeon is indicated for management of delayed union.
IMAGES COURTESY OF HANS P. VAN LANCKER, MD, FRCSC
Common indications for referral to Orthopedics for surgical intervention of ankle fracture include open fracture, bimalleolar and trimalleolar fracture, posterior malleolar fracture, medial malleolar displacement > 2 mm, and lateral malleolar displacement > 3 mm.18
Special concern: Talar fracture. Although talar fracture is rare, the injury is important to detect because a limited blood supply places fragments at risk of avascular necrosis.19 Talus fracture is frequently confused with ankle sprain because initial x-rays are not always revelatory.20 A high index of suspicion is required to make the diagnosis, which should be suspected in high-energy injuries that result in pain and swelling of the ankle accompanied by difficulty weight-bearing, severely reduced range of motion, and tenderness to palpation at different areas of the talus.1 Computed tomography (CT) or MRI might be necessary to detect a talar fracture if initial x-rays are negative. A low threshold for surgical management of talar fracture means that referral to Orthopedics is indicated once this injury is diagnosed.21
Continue to: Other frequently missed types of ankle fracture