Review Question - QID 5592

Figure A shows a minimally displaced Weber B ankle fracture. The need for operative treatment would be dependent on fracture stability. A gravity stress test would best demonstrate fracture displacement, syndesmotic injury and medial sided ligamentous integrity.

In patients who present with no medial widening on standard ankle radiographs and no clinical symptoms of deltoid ligament injury, the integrity of the deltoid ligament remains unknown. The gravity stress radiograph may be used to help identify a deltoid ligament injury in association with an isolated distal fibular fracture. Stage-IV supination-external rotation fractures, which involve the deltoid ligament, are more likely to be treated operatively as they are often considered unstable ankle fractures.

Egol et al. reviewed 101 patients with isolated fibular fracture and an intact mortise. They found that medial tenderness, swelling, and ecchymosis were not sensitive with regard to predicting widening of the medial clear space on stress radiographs. Interestingly, they report that good functional results can be obtained in patients with widening of the medial clear space on a stress radiograph in the absence of medial signs.

Gill et al. compared the effectiveness of gravity stress radiograph as compared to manual stress radiograph for the detection of deltoid ligament injury in isolated fibular fracture. A total of twenty-five patients with SER type-II fracture and SER Type IV-equivalent fractures were enrolled. They found the gravity stress radiograph was equivalent to the manual stress radiograph for determining deltoid ligament injury.

Figure A shows a mortise radiograph displaying a minimally displaced Weber B ankle fracture. Illustration A shows the positioning for a gravity stress radiograph. The patient is in the lateral decubitus position with the injured leg dependent and off the end of the table, a mortise view is taken in 10° of internal rotation of the tibia.

Incorrect Answers:
Answers 1-2: Differentiation between stage-II and stage-IV supination-external rotation fractures (Lauge-Hansen Classification) is clinically relevant as an intact deltoid ligament stabilizes the ankle mortise and open reduction is thought to be unnecessary. The best way to determine deltoid integrity would be to perform a gravity stress radiograph.
Asnwer 3: The cotton test is an intra-operative test to assess for syndesmotic injury. It would not be used in an awake patient for this purpose.
Answer 5: A positive squeeze test is suggestive of a syndesmotic injury. However, this test has a lower sensitivity for detecting syndesmotic injury in comparison to stress radiographs.