Finite Element Analysis of 2- and 3-Point Internal Fixation Methods for the Treatment of Zygomaticomaxillary Complex Fracture.

Open reduction followed by internal fixation (ORIF) has been regarded as the most effective technique for surgical repair of zygomaticomaxillary complex (ZMC) fractures. However, the ideal internal fixation method to achieve stable reduction remains controversial. This research aims to assess and compare the stability of the 2- and 3-point screw-plate fixation methods using finite element method (FEM). Based on computed tomography (CT), the finite element models of 2-point (ZFS + IOR) and 3-point (ZFS + IOR + ZMB) fixation for isolated displaced ZMC fracture were reconstructed. The force of 120 N was applied to the models to simulate the masseter muscle strength. The maximum stress and displacement of the 2 models were measured to compare the stability. Two geometrically accurate and finite element models were reconstructed successfully. In both the 2- and 3-point fixation models, the maximum stress was significantly lower than the mechanical properties of pure titanium and titanium alloys and the maximum displacement was ≤0.1 mm. The results of this study suggested that both 2- and 3-point fixation of isolated displaced ZMC fractures provide good stability. The FEM innovatively applied in this study can not only show the biomechanical properties of the orbital skeleton and masseter muscle but also assess the stability of the two fixation methods and provide a theoretical reference. This study verifies the effectiveness of 2-point fixation and combined with the clinical benefits of reduced incisions, shorter operative time and lower cost, make this an attractive method.