Anteroposterior radiograph of the tibia and fibula of a 29-year-old man who slipped and fell shows an oblique fracture of the proximal fibula.
Lateral radiograph of the patient’s tibia and fibula also shows an oblique fracture of the proximal fibula.
Anteroposterior mortise radiograph of the patient’s ankle shows no fracture or syndesmotic widening.
Lateral radiograph of the patient’s ankle also shows no fracture or syndesmotic widening.
A 29-year-old man presents to the emergency department with pain in his left leg and ankle after slipping on ice. He felt like the ankle twisted under him, and he has had difficulty bearing weight since. On examination, the patient has pain over the proximal fibula and over the ankle at the deltoid ligament and anterior tibiofibular ligament. He has diffuse swelling over both the medial and lateral ankle as well. Anteroposterior and lateral radiographs of the tibia and fibula show an oblique fracture of the proximal fibula. Anteroposterior mortise and lateral radiographs of the ankle show no fracture or syndesmotic widening.
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The patient’s proximal fibula fracture with ankle swelling is consistent with a syndesmotic disruption and Maisonneuve injury pattern. Maisonneuve fractures are often missed on initial evaluation, and therefore, full-length radiographs of the tibia/fibula should be ordered after a significant ankle injury, particularly if radiographs of the ankle appear normal.
It is important to understand that Maisonneuve injury is not just an isolated fibular fracture. The injury generally occurs as the result of a torsional injury of the ankle when the force of the injury is transmitted along the interosseous ligament to the proximal fibula. The injury pattern also commonly causes disruption of the anterior tibiofibular ligament and tear of the medial deltoid ligament.
The mortise-view radiograph of the ankle is the most important diagnostic modality to determine whether a significant syndesmotic injury has occurred. Increased medial clear space, measured from the lateral border of the medial malleolus to the medial border of the talus on the mortise view, indicates a deltoid ligament injury. Medial clear space widening is also the most reliable indicator of a syndesmotic injury.
Any evidence of syndesmosis widening on radiographs is an indication for surgery, which includes syndesmosis screw fixation. If there is no syndesmosis widening, nonoperative treatment is recommended. This includes a non-weight-bearing period for 4 to 6 weeks with progressive weight bearing to tolerance thereafter. Patients are often placed in a non-weight-bearing boot or short leg cast during this time. Patients should be advised that the recovery time for syndesmotic injuries can be twice as long as for a typical ankle sprain and can take 2 to 3 months before return to normal function.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Pankovich AM. Maisonneuve fracture of the fibula. J Bone Joint Surg Am. 1976;58:337-342.
- Karadsheh M. High ankle sprain and syndesmosis injury. OrthoBullets website. http://www.orthobullets.com/foot-and-ankle/7029/high-ankle-sprain-and-syndesmosis-injury. Accessed May 9, 2017.