Flexible Syndesmotic Reconstruction with Two Suture Buttons Provides Equal Stability Compared to Syndesmotic Screws: A Biomechanical Study

Background: This study investigated syndesmotic stability after transection and the effects of stabilization using rigid and dynamic reconstruction techniques. Methods: Syndesmotic stability was analyzed using a six-degree-of-freedom robotic arm on 14 human specimens. Stability was analyzed in the neutral position and during dorsiflexion and plantar flexion using an external rotation stress test under an axial load of 200 Newtons. The examination was performed on intact and sequentially transected syndesmosis in the following order: (1) anterior inferior tibiofibular ligament (AITFL); (2) interosseous ligament (IOL); and (3) posterior inferior tibiofibular ligament (PITFL). Then, reconstruction was performed using different syndesmotic screw techniques or a dynamic Suture Button system (Arthrex TightRope; n = 7). Results: A syndesmotic transection mainly caused sagittal instability of the fibula. While both static and dynamic reconstruction provided stabilization, screw fixation, particularly with two screws and a plate, demonstrated superior control of the fibular movement, especially in the sagittal and transverse planes, compared to one Suture Button. Conclusions: The results suggest that syndesmotic stabilization with one Suture Button may be insufficient for cases involving three-ligamentous injuries, whereas two Suture Buttons may offer comparable biomechanical stability to syndesmotic screws. Additionally, the study suggests that lateral radiographs may provide additional clinical value in assessing syndesmotic stability.