Stabilization of the Syndesmosis in the Maisonneuve Fracture-A Biomechanical Study Comparing 2-Hole Locking Plate and Quadricortical Screw Fixation

Objective: The aim of this study is to determine whether a 2-hole locking plate has biomechanical advantages over conventional screw stabilization of the syndesmosis in this injury pattern. Methods: Six pairs of fresh-frozen human cadaver lower legs were prepared to simulate an unstable Maisonneuve fracture. Each limb was compared with its pair; the syndesmosis in one being stabilized with two 4.5-mm quadricortical cortical screws, the other a 2-hole locking plate with 3.2-mm locking screws. The limbs were then mounted on a servohydraulic testing rig and axially loaded to a peak load of 800N for 12000 cycles. Fibula shortening and diastasis were measured. Each limb was then externally rotated until failure occurred. Failure was defined as fracture of bone or metalwork, syndesmotic widening, or axial migration >2 mm. Results: Both constructs effectively stabilized the syndesmosis during the cyclical loading within 0.1 mm of movement. However, the locking plate group demonstrated greater resistance to torque compared with quadricortical screw fixation (40.6 Nm vs. 21.2 Nm, respectively, P value < 0.03). Conclusion: A 2-hole locking plate (with 3.2-mm screws) provides significantly greater stability of the syndesmosis to torque when compared with 4.5-mm quadricortical fixation.