Cite This Article

Duong, H. Marshall, J. Negaard, M. Tomesch, A. A Sudden Turn of the Ankle. Ortho Pearls. March 19, 2025; Available: https://www.orthoempearls.com/articles/a-sudden-turn-of-the-ankle

What is the diagnosis?

Trimalleolar equivalent open ankle fracture (Weber C) with lateral talar subluxation. 

 

Image 3. AP view X-ray imaging of the right ankle with annotations demonstrating lateral malleolus fracture (yellow arrow) and loss of mortise congruence (red arrow). Author’s own image. 

 

Image 4. CT imaging demonstrating lateral and posterior malleolar fracture pattern with lateral talar dislocation. Author’s own images. 

What is the mechanism of injury?

Ankle fractures are typically a result of inversion vs eversion injuries (as in this case). 

What physical exam findings are expected?

Most isolated unimalleolar fractures are stable, thus you can expect normal strength testing, palpable pulses, and primarily bony tenderness over the isolated fractured region with surrounding soft tissue swelling. 

In this case, there was an obvious open fracture with concern for an unstable fracture pattern (bimalleolar or above) with clear talar dislocation. Palpating for pulses can reveal pulselessness until appropriate re-location of the dislocated joint. 

• Pearl: Make sure to examine the proximal fibula during ankle examinations, especially in higher grade injuries, to rule out Maisonneuve fractures (a proximal fibular fracture in addition to an unstable ankle injury with disruption of the tibio-fibular syndesmosis).  Maisonneuve fractures make up approximately 7% of injuries and can be easily missed as x-ray findings can show subtle joint widening without obvious bony fracture [1][2].

What imaging modalities can be used?

If an ankle fracture is suspected (and not obvious as in this one), X-ray imaging is typically first line. Be sure to include multiple views including the mortise view in order to evaluate for appropriate talar placement and widening of the mortise syndesmosis as subtleties there can reveal concern for unstable ligamentous injuries. 

The denis-weber classification system is often used to identify degree of fracture instability and refers to the level of the fibular fracture in relation to the tibio-fibular syndesmosis [3].

Studies have shown however that Weber classifications and relationship to functional outcome was more dependent on the number of malleoli involved [4].

CT scans are obtained for surgical planning if there is concern for highly unstable ankle fracture or if there is concern for occult fracture not easily identifiable on x-ray imaging.

Image 5. Weber classifications for ankle injuries. Image provided by radiopaedia.org, illustrated by Dr. Frank Gaillard rID: 9642

What is the management in the ED/when should you consult orthopedics?

Most isolated unimalleolar fractures without major talar shift are stable. Bimalleolar, bimalleolar equivalent (involvement of deltoid ligament), or trimalleolar typically require orthopedic surgery consultation for intervention of an unstable ankle fracture. All open fractures should have orthopedic consultation in the ED for definitive management, regardless of age [5]. Physicians should promptly reduce large displaced open fractures if there is concern for vascular compromise.