Comparative finite element analysis of a novel distal tibiofibular locking plate versus conventional fixation methods...

Tillaux-Chaput fractures are avulsion fractures involving the tibial insertion of the anterior inferior tibiofibular ligament. Inadequate fixation may result in distal tibiofibular syndesmotic instability and post-traumatic ankle arthritis. Conventional fixation methods, such as cannulated screws and suture anchor fixation, exhibit inherent limitations in the management of small or comminuted fragments. This study aimed to compare the biomechanical performance of cannulated screw fixation, suture anchor fixation, and a newly developed distal tibiofibular locking plate system for Tillaux-Chaput fractures using finite element analysis.

Computed tomography data from a healthy adult male ankle were used to reconstruct a three-dimensional finite element model consisting of the tibia, fibula, and talus. A Tillaux-Chaput fracture was simulated at the anterolateral distal tibia. Four fixation models were established: cannulated screw fixation, suture anchor fixation, and two configurations of the novel locking plate system. Five physiological loading conditions were simulated, including plantar flexion, dorsiflexion, internal rotation, external rotation, and single-leg standing. The maximum von Mises stress and total displacement of both the fracture fragment and fixation devices were evaluated.

Across all loading conditions, the novel locking plate configurations exhibited lower peak stress and displacement of the fracture fragment than both cannulated screw and suture anchor fixation. The plate-2 fixation demonstrated the most favorable overall performance, with fracture fragment stress ranging from 2.28 to 4.70 MPa under non-standing conditions and 4.63 MPa during single-leg standing. Under internal and external rotation, the cannulated screw model showed the highest fragment stress, reaching 30.72 and 29.42 MPa, respectively. During single-leg standing, the suture anchor fixation showed the highest fragment stress of 43.19 MPa. The locking plate models also exhibited a more uniform stress distribution and better control of fragment displacement, particularly under torsional loading.

The novel distal tibiofibular locking plate system provided superior biomechanical stability compared with cannulated screw and suture anchor fixation in this finite element model of Tillaux-Chaput fracture. By combining plate support, locking screw fixation, and suture-assisted reinforcement, this system may offer a promising fixation strategy for small and comminuted Tillaux-Chaput fragments.