Abstract
To determine the optimal direction of the syndesmotic screw and to introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation. A total of 105 cadaveric lower legs (50 males and 55 females; average height, 160.6 ± 7.1cm) were used to reconstruct a 3D model by using the Mimics® software and the joint morphology was evaluated. Syndesmotic cylinders (Ø3.5mm/Length 100mm) were transversely placed in the proximal end of the incisura fibularis for simulating screw fixation. The tibial proximal cylinder, which was tangent to the posterior tibial condyles, was traced and the angle between the two cylinders was measured as the tibial torsion angle (TTA). After rotating the syndesmotic cylinder parallel to the ground, the overlapping degree between the proximal fibula and tibia was assessed as a radiologic indicator. Concerning tibial torsion, the TTA was an average of 36.7° (range, 17.2°-54.4°; SD, 8.78) When the syndesmotic cylinder was rotated to be parallel to the ground, the proximal fibula had nonlinear or linear overlap with the lateral border of the tibia, regardless of the joint morphology. In this non-overlapping view, three Weber's indices for normal fibular length could be better visualized than the mortise view. The syndesmotic cylinder in the proximal end of the incisura fibularis could be consistently placed parallel to the ground by internally rotating the tibia until there was a nonlinear or linear overlap between the proximal fibula and the tibia, regardless of the joint morphology.
Highlights
To determine the optimal direction of the syndesmotic screw and introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation
Concerning tibial torsion, the tibial torsion angle (TTA) was an average of 36.7°
Regardless of individual variation in tibial torsion, the 3D biplanar images consistently showed that the proximal fibula was non- or linearly overlapping with the tibia in the syndesmotic AP projection of all models (Fig. 2 nonoverlap)
Summary
To determine the optimal direction of the syndesmotic screw and introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation. Syndesmotic injury/instability often occurs concurrently with ankle fractures and, until recently, has been treated solely with a transsyndesmotic screw. The dynamic suture-button technique has become more conventional owing to possible advantages compared to typical transsyndesmotic screws.[1] Regardless of the fixation options, the optimal trajectory of the guideline for positioning the definitive implant is the most important factor in preventing iatrogenic malreduction.[2, 3] Concerning the management of syndesmotic instability, first of all, surgeons intraoperatively verify the reduction adequacy by conventional radiography, including plain and fluoroscopic methods, without special equipment. The leg must be rotated internally 15°–20°, aligning the intermalleolar line parallel to the detector and usually results in the 5th toe being directly in line with the center of the calcaneum.[5, 6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
