What's the diagnosis? By Dr. Michael Tom
Wed, 01/09/2019 - 1:21pm
Editor:
A 24 yo male presents with ankle pain after attempting a flip and twisting his ankle. Plain films are shown. What's the diagnosis? Scroll down for answer.
Answer: Disruption of the ankle mortise and syndesmosis with posterior malleolus fracture
- most common mechanism of injury is external rotation
- commonaly missed injury so must pay close attention to mortise and talofibular overlap
- normal medial clear space <4mm -- space between medial malleolus and talus)
- normal tibiofibular clear space is <6mm -- space between the lateral border of the posterior tibia (incisural fibularis) and the medial border of the fibula (measured 1cm proximal to plafond)
- positive squeeze test = pain at distal syndesmosis with squeeze at mid tibia/fibula
- stress radiographs may be helpful, CT or MRI if clinical suspicion is high in the setting of normal plain films
- commonly associated with proximal fibular fracture (Maisonneuve, which this patient had)
- instability suggested by stress radiographs is an indication for surgery
- good functional outcomes are seen with anatomic reduction
Reference:
Hunt, K. J. (2013). Syndesmosis injuries. Current Reviews in Musculoskeletal Medicine, 6(4), 304-312. doi:10.1007/s12178-013-9184-9