Imaging Case of the Week 115

This left ankle x-ray is from a 55 year old experiencing ankle pain and swelling after a twisting injury to his ankle. What can you see? And what other x-ray would you request?

 

Left ankle xrays

 

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The x-ray shows soft tissue swelling over the medial as well as the lateral malleolus. There is abnormal widening of the medial joint space of the ankle and a syndesmotic widening with an avulsion fracture of the distal tibia near the syndesmosis. There is also an avulsion fracture visible near the medial aspect of the talus. Could this just be a case of severe ligament injury with a few avulsion fractures?

 

Left ankle subluxation with syndesmotic injury

 

This pattern of injury (deltoid ligament disruption with syndesmotic injury) should alert one to the possibility of a fracture high up in the fibula. A leg x-ray conducted on this patient revealed a fibular neck fracture, confirming the presence of a Maisonneuve fracture.

Left leg x-ray fibular neck fracture

Maisonneuve fracture is a high fibular fracture associated with either medial malleolar fracture or a deltoid ligament injury.

An eversion force combined with external rotation of the ankle first disrupts the deltoid ligament, causing a sprain or fracturing the medial malleolus. As the force continues, it causes a rupture of the anterior tibiofibular ligament, the interosseous ligament between the tibia and fibula, and finally fracturing the proximal fibula.

Maisonneuve fracture is an unstable injury and needs orthopaedic referral from the ED. This particular patient was managed operatively.

Reference: http://www.wheelessonline.com/ortho/maisonneuve_fracture

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