Is fibular fracture displacement consistent with tibiotalar displacement?

Abstract

We believed open reduction with internal fixation is required for supination-external rotation ankle fractures located at the level of the distal tibiofibular syndesmosis (Lauge-Hanssen SER II and Weber B) with 2 mm or more fibular fracture displacement. The rationale for surgery for these ankle fractures is based on the notion of elevated intraarticular contact pressures with lateral displacement. To diagnose these injuries, we presumed that in patients with a fibular fracture with at least 2 mm fracture displacement, the lateral malleolus and talus have moved at least 2 mm in a lateral direction without medial displacement of the proximal fibula. We reviewed 55 adult patients treated operatively for a supination-external rotation II ankle fracture (2 mm or more fibular fracture displacement) between 1990 and 1998. On standard radiographs, distance from the tibia to the proximal fibula, distance from the tibia to the distal fibula, and displacement at the level of the fibular fracture were measured. These distances were compared preoperatively and postoperatively. We concluded tibiotalar displacement cannot be reliably assessed at the level of the fracture. Based on this and other studies, we believe there is little evidence to perform open reduction and internal fixation of supination-external rotation II ankle fractures.

Level of evidence: Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence.

Fig. 1A–B

Three distances were measured on the (A) preoperative and (B) postoperative radiographs to compare fibular fracture displacement with lateral displacement of the distal fibula and talus (1) displacement between the proximal fibula and distal tibia; (2) displacement between the distal fibula and distal tibia; and (3) fibular fracture displacement.

Fig. 2

The external rotation of the supinated foot stopped before medial injury occurred. The deltoid ligament becomes taut because the deep part of this ligament limits external rotation of the talus with the foot in supination.

Fig. 3

At the end of this external rotating, the distal fibular fragment internally rotates and this will happen without movement between the fracture fragments. The result is the distal fragment is in neutral position and the proximal fibular fragment is in an internally rotated position.