- Sequence of Injury:
- medial side is injuried first;
- transverse frx of medial malleolus or disruption of deltoid ligament;
- anterior tibiofibular ligament disruption;
- external rotation then results in rupture of the anterior tibiofibular ligament or its bony insertion;
- short oblique or spiral frx of fibula above the level of the joint;
- spiral fibular frx, w/ distal end usually 4 to 7 cm above tibial plafond (and hence, the frx is above the syndesmotic ligaments);
- fibular frx is spiral, but runs anterosuperior to posteroinferior, & interosseous membrane is ruptured up to the level of fibula frx;
- posterior injury:
- tibiofibular ligament rupture or avulsion of posterior malleolus;
- Treatment: (same as Weber C)
Mechanical considerations for the syndesmosis screw. A cadaver study.
Instability of the distal tibiofibular syndesmosis after bimalleolar and trimalleolar ankle fractures.
The effect of fibular malreduction on contact pressures in an ankle fracture malunion model.