A 24-Year-Old Man with Ankle Pain After a Fall

Differential Diagnosis

• Ankle sprain
• Adult Tillaux fracture
• Medial malleolus fracture

Diagnosis

This patient suffered an adult Tillaux fracture, which is a fracture of anterolateral tibial epiphysis. This occurs more commonly in adolescents and only rarely in adults. This is seen as an oblique lucency extending from the lateral distal tibia toward the midline articular surface of the distal tibia. This is an avulsion fracture of the anterolateral part of the tibial plafond.

Learnings/What to Look for

• In adult Tillaux fracture, the avulsed fragment is triangular, while in juvenile Tillaux fracture it is quadrangular
• The mechanism of injury is an inversion of the ankle while the foot is in supination with external rotation resulting in an avulsion fracture of the anterolateral tibial plafond due to a taut intact anteroinferior tibiofibular ligament
• It is not well seen on AP and lateral standard radiographic views of the ankle, so an oblique view (mortise) should be performed if this injury is suspected
• It can rarely be associated with injury of the medial malleolus or deltoid ligament

Pearls for Urgent Care Management

• If fracture displacement is <2 mm, this injury can be managed conservatively (ie, non-weightbearing cast or brace for 6 weeks, followed by physical therapy as needed)
• If the fracture fragment is displaced >2 mm, referral to an orthopedist for surgical consideration is warranted. The patient may need to undergo closed reduction or open reduction and internal fixation

Acknowledgment: Images and case presented by Experity Teleradiology (www.experityhealth.com/radiology).