Safety of Ankle Trans-Syndesmotic Fixation

Abstract

Background: Ankle syndesmosis fixation is often employed with the utilization of many variable methods and implants. Complications secondary to trans-syndesmotic fixation have been described, yet the proximity of a single trans-syndesmotic screw to the perforating branch of the peroneal artery (PBPA) has not. Materials and Methods: Sixteen cadaveric legs received a single trans-syndesmotic screw using standard AO technique. The PBPA was identified and the following distances were measured using photographic images and morphometric software: the tip of lateral malleolus to the PBPA, the tibial plafond to the PBPA, tip of lateral malleolus to the screw, and the PBPA to the screw. Average distances were calculated and statistically compared. Results: The location of the trans-syndesmotic screw inserted 2 cm proximal to the tibial plafond was on average less than 1.3 cm proximal to the PBPA. In six out of the 16 specimens, the screw was less than 1 cm from the PBPA. In one specimen, the screw came within 0.22 cm of the PBPA. Conclusion/Clinical Relevance: The placement of trans-syndesmotic fixation places the PBPA at risk. In order to avoid injury to the PBPA with trans-syndesmotic fixation, fixation should be avoided 2.3 to 4.1 cm proximal to the tibial plafond, 4.5 to 6.2 cm proximal to the tip of the lateral malleolus in females and 2.8 to 5.9 cm proximal to the tibial plafond or 5.1 to 7.2 cm proximal to the tip of the lateral malleolus in males.