Slideshow
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Figure 1. Radiographic view of displaced talus fracture.
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Figure 2. Anteroposterior view of closed reduction of ankle.
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Figure 3. Lateral view of ankle postreduction.
A 39-year-old woman presents to the emergency department with severe right ankle pain following a motorcycle accident. She has an obvious valgus deformity to the ankle but the skin is intact. Anteroposterior radiograph of the talus neck shows a fracture and subtalar joint dislocation (Figure 1). The ankle is treated by closed reduction and splint in the emergency department to relieve pressure on the lateral skin. Anteroposterior and lateral radiographs taken after reduction are shown in Figures 2 and 3, respectively. The patient is admitted to the hospital and brought to the operating room for open reduction and internal fixation of the talus fracture the next day.
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The talus has a limited vascular supply and more than half of its surface covered by articular cartilage.1 The most common type of talus fracture is a talus neck fracture.1 Neck fractures with >2 mm of displacement require surgical fixation. Fractures with significant displacement should be treated with urgent closed reduction to protect the blood supply and promote revascularization.1,2
Depending on fracture displacement, osteonecrosis can be a common complication that arises from displaced fractures.1-4 An Hawkins type II fracture, as seen in this patient, has an 18.4% to 39% chance of developing avascular necrosis (AVN) even with closed reduction and surgical fixation.3,4 Comparably a minimally displaced Hawkins type I fracture has a 6% to 10% chance of AVN. For type III fractures, the risk of AVN is 45% to 90%.1-4
The appearance of osteonecrosis on radiographs can start on average at 7 months after surgical fixation, with a range of 3 to 9 months.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopaedics for Physician Assistants.
References
1. Lee C, Brodke D, Perdue PA Jr, Patel T. Talus fractures: evaluation and treatment. J Am Acad Orthop Surg. 2020;28(20):e878-e887. doi:10.5435/JAAOS-D-20-00116
2. Vallier HA, Nork SE, Barei DP, Benirschke SK, Sangeozan BJ. Talar neck fractures: results and outcomes. J Bone Joint Surg Am. 2004;86(8):1616-1624.
3. Vallier HA, Reichard SG, Boyd AJ, Moore TA. A new look at the Hawkins classification for talar neck fractures: which features of injury and treatment are predictive of osteonecrosis? J Bone Joint Surg Am. 2014;96(3):192-197. doi:10.2106/JBJS.L.01680
4. Lin SS, Montemurro NJ. New modification of the Hawkins classification scheme is more predictive of osteonecrosis. J Bone Joint Surg Am. 2014;96(3):e25. doi:10.2106/JBJS.M.01465
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