Review Question - QID 219836

This patient sustained an injury to the syndesmosis, or high ankle sprain, as evidenced by the tibiofibular diastasis best seen on the mortise view of the ankle. These injuries are commonly associated with fractures of the proximal fibula, or Maisonneuve fractures (Answer 3).

High ankle sprains involve an injury to the syndesmosis and commonly a large portion of the interosseous membrane. The significant external rotation forces required to produce this injury often result in fractures of the proximal fibula, though there may not be appreciable fractures to the malleoli. The energy of the mechanism is instead transferred to the syndesmosis, up the interosseous membrane, and into the region of the fibular neck. The presence of fractures in this region increases the diagnostic suspicion of a significant injury to the interosseous soft tissue stabilizers (interosseous membrane and the syndesmotic ligaments). The resulting instability at the ankle joint therefore often requires operative management. Additionally, these fractures are easily missed, with a missed diagnosis rate of 14-44%. It is therefore important to obtain full-length radiographs of the tibia and fibula, in addition to a standard three-view ankle series, to evaluate for fractures about the proximal leg.

Stufkens et al. published a 2011 systematic review of the then-current literature on Maisonneuve fractures to make recommendations for clinical practice. The authors searched several databases over a 40-year period to identify studies relating to the treatment of Maisonneuve ankle fractures. They found that outcomes following treatment were generally good, and formulated grade B and C recommendations for the treatment of Maisonneuve fractures, including: 1) the medial malleolus should be fixed, 2) the torn deltoid ligament need not be directly repaired, 3) syndesmotic instability can be treated with one or two 3- or 4-cortical screws and these can be placed percutaneously, and 4) the proximal fibular fracture does not require direct internal fixation.

He et al. published a single-center 2020 retrospective review of 41 patients presenting with Maisonneuve fractures. Mechanism of injury, radiographic evaluation, concomitant injuries, and treatment modality were analyzed. The authors found several associated injuries, including medial malleolar fractures, deltoid ligament ruptures, ruptures of the posterior inferior tibiofibular ligament (PITFL), posterior malleolar fractures, and ruptures of the anterior inferior tibiofibular ligament (AITFL).

Figure A is an AP radiograph demonstrating diastasis of the distal tibiofibular joint.
Figure B is a mortise radiograph demonstrating diastasis of the distal tibiofibular joint.
Figure C is a lateral radiograph of the injured ankle.
Illustration A is a full-length lateral radiograph of the injured leg in the same patient, demonstrating a Maisonneuve fracture.

Incorrect Answers:
Answer 1: In this patient, the lateral malleolus appears intact, without fracture.
Answer 2: Proximal tibiofibular dislocations are rare, high-energy injuries and have not been associated with syndesmotic injuries.
Answer 4: Injury to the AITFL, not the ATFL, is almost always associated with syndesmotic injuries.
Answer 5: Injury to the CFL has not been associated with syndesmotic injuries.