The Radiographic Fate of the Syndesmosis after Trans-syndesmotic Screw Removal in Displaced Ankle Fractures

The purpose of this study was to evaluate the radiographic changes of the tibiofibular position and the ankle mortise after removal of trans-syndesmotic fixation to determine if there is loss or maintenance of correction. In addition, the effect of the type of rotational injury, early weight bearing, and the number of trans-syndesmotic screws used on the integrity of the inferior tibiofibular articulation or ankle mortise after screw removal were evaluated. An analysis was conducted of 86 patients, with an unstable rotational ankle fracture requiring open reduction with syndesmosis screw stabilization. Routine radiographic parameters were measured just after open reduction and just before syndesmotic screw removal. There was a high correlation of loss of the integrity of the syndesmotic parameters after screw removal. However, the medial clear space of the ankle changed an insignificant amount, suggesting that although there appears to be some loss of maintenance, the talus did not shift laterally at the expense of a mobile syndesmosis. Ankle injuries requiring stabilization of syndesmotic instability with use of temporary trans-syndesmotic fixation achieve a stable ankle mortise after removal. Tibiofibular diastasis is commonplace upon removal of the syndesmotic hardware, but the ankle mortise remains unchanged. Based on the radiographic criteria described in this study, the postoperative change in medial clear space or tibiofibular diastasis has no bearing on fracture type, deltoid injury, or the use of 1 or 2 cortical screws. As such, other unknown mechanisms affecting the integrity of the syndesmosis after screw removal are in place.