Hybrid Fixation Restores Tibiofibular Kinematics for Early Weightbearing After Syndesmotic Injury

Abstract

Background: Disruption of the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), and interosseous membrane (IOM) is a predictive measure of residual symptoms after an ankle injury. Controversy remains regarding the ideal fixation technique for early return to sport, which requires restoration of tibiofibular kinematics with early weightbearing. Purpose: To quantify tibiofibular kinematics after syndesmotic fixation with different tricortical screw and suture button constructs during simulated weightbearing. Study Design: Controlled laboratory study. Methods: A 6 degrees of freedom robotic testing system was used to test 9 fresh-frozen human cadaveric specimens (mean age, 65.1 ± 17.3 years). A 200-N compressive load was applied to the ankle, while a 5-N·m external rotation and a 5-N·m inversion moment were applied independently to the ankle at 0° of flexion, 15° and 30° of plantarflexion, and 10° of dorsiflexion. Fibular medial-lateral translation, anterior-posterior translation, and internal-external rotation relative to the tibia were tracked by use of an optical tracking system in the following states: (1) intact ankle; (2) AITFL, PITFL, and IOM transected ankle; (3) single-screw fixation; (4) double-screw fixation; (5) hybrid fixation; (6) single suture button fixation; and (7) divergent suture button fixation. Repeated-measures analysis of variance with Bonferroni correction was performed for statistical analysis. Results: In response to the external rotation moment and axial compression, single tricortical screw fixation resulted in significantly higher lateral translation of the fibula compared with that of the intact ankle at 10° of dorsiflexion ( P < .05). Suture button fixation resulted in significantly higher posterior translation of the fibula at 0° of flexion and 10° of dorsiflexion, whereas divergent suture button fixation resulted in higher posterior translation at only 0° of flexion ( P < .05). In response to the inversion moment and axial compression, single tricortical screw and hybrid fixation significantly decreased lateral translation in plantarflexion, whereas double tricortical screw fixation and hybrid fixation significantly decreased external rotation of the fibula compared with that of the intact ankle at 15° of plantarflexion ( P < .05). Conclusion: Based on the data in this study, hybrid fixation with 1 suture button and 1 tricortical screw may most appropriately restore tibiofibular kinematics for early weightbearing. However, overconstraint of motion during inversion may occur, which has unknown clinical significance. Clinical Relevance: Surgeons may consider this data when deciding on the best algorithm for syndesmosis repair and postoperative rehabilitation.

Dual Suture Button Fixation With Buttress Plate for Ankle Syndesmotic Injury

“…8,9 Biomechanical studies have produced conflicting evidence regarding the superiority of dual suture button devices compared with single suture button device. 10,11 We prefer 2 divergent points of fixation across the syndesmosis and the use of a buttress plate to prevent subsidence of the buttons into the lateral fibular cortex.…”

Ultrasound-Guided Anterior Talofibular Ligament Repair With Augmentation Can Restore Ankle Kinematics: A Cadaveric Biomechanical Study

“…After the tibial side was potted in an epoxy compound (Bondo; 3M), the calcaneus and attached screws were potted in a cylindrical mold (Figure 1). 19…”

“…The tibial clamp was rigidly fixed to the lower plate of the robotic testing system, and the calcaneal clamp was attached to the upper end plate of the robotic manipulator through a universal force/moment sensor (model SI-660-60; ATI Delta IP60), which was used to provide feedback to the controller (Figure 2). 19…”

“…After the tibial side was potted in an epoxy compound (Bondo; 3M), the calcaneus and attached screws were potted in a cylindrical mold (Figure 1). 19 The ankle was mounted onto a 6 degrees of freedom (6DOF) robotic testing system (model FRS2010; MJT). The position and orientation repeatability of the robotic testing system were less than ±0.015 mm and ±0.01 , respectively.…”

“…The tibial clamp was rigidly fixed to the lower plate of the robotic testing system, and the calcaneal clamp was attached to the upper end plate of the robotic manipulator through a universal force/moment sensor (model SI-660-60; ATI Delta IP60), which was used to provide feedback to the controller (Figure 2). 19 The measurement uncertainty of the universal force/ moment sensor was approximately 1% of full scale. The system was controlled by a LabVIEW program (Technology Services Inc) designed for ankle biomechanical testing and was operated in hybrid velocity-impedance control.…”