A 23-year-old male presents to the emergency department with right ankle pain after he rolled his ankle while walking down the stairs. An ankle exam reveals ecchymosis over the posterior ankle and tenderness of the distal tibia. His neurovascular exam is intact. The radiograph above was obtained (Image 1. X-ray right ankle. Original image provided by Justine Ko, MD).
The patient is diagnosed with an isolated posterior malleolar fracture. These generally arise from a rotational force.
- Pearl: Be aware of other fractures and syndesmotic injury as posterior malleolar fractures are often associated with more complex injuries. Only 1–4% are isolated posterior malleolar fractures [1].
- Pearl: An isolated posterior malleolar fracture is also known as a Volkmann’s fracture or Earle’s fracture [2].
Posterior malleolar fractures can be easily missed (Image 2). X-ray images should be used for diagnosis, with special attention to the lateral view. CT scan can be used for indeterminate cases and to better evaluate the fracture fragment [2].
- Pearl: Weight-bearing x-rays can be helpful in assessing concomitant syndesmotic injuries and medial mortise widening.
Image 2: Lateral ankle radiograph. Original image provided by Justine Ko, MD with the red arrow pointing toward the fracture line.
Patients should be placed in a posterior mold splint with the ankle in a neutral position and be made non-weight bearing. Close follow-up with orthopedics is important as many of these injuries may require surgery.
- Pearl: Surgery indications are not clearly defined. The size of the fragment and the percentage of articular surface involvement contributes to this decision [3].
Resources & References:
Review EMRad’s Radiological Approach to the Traumatic Ankle to brush up on your interpretation of ankle x-rays.
- Bergman C, Morin M, Lawson K. Anatomy, Classification, and Management of Ankle Fractures Involving the Posterior Malleolar Fragment: A Literature Review. Foot & Ankle Orthopaedics. 2019;4(4):2473011419887724. PMID: 35097350
- Smeeing DPJ, Houwert RM, Kruyt MC, Hietbrink F. The isolated posterior malleolar fracture and syndesmotic instability: A case report and review of the literature. Int J Surg Case Rep. 2017;41:360-365. PMID: 29149741
- Serbest S, Tiftikçi U, Tosun HB, Kesgin E, Karataş M. Isolated posterior malleolus fracture: a rare injury mechanism. Pan Afr Med J. 2015;20:123. PMID: 26097627
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