Biomechanical evaluation of various internal fixation patterns for unilateral mandibular condylar base fractures: A...

Finite element analysis (FEA) could efficiently simplify the mechanical behaviors of complex loaded constructions. Condylar base fracture related FEAs have been always published, but it is absent for the therapeutic effects of diverse implanting devices' locations and materials on osteosynthesis. The current FEA aimed to elucidate the biomechanical effects of unilateral mandibular condylar base fractures with open reduction and internal fixation (ORIF) of different locations and materials. The implanting positions included posterolateral border of ramus (A), anterolateral border along sigmoid notch (B), and lateral border in the middle area (C). Two different materials were presented, titanium and u-HA/PLLA (Poly-L-lactic acid combined with uncalcined and unsintered hydroxyapatite). For titanium, A + B presented lowest values of maximum von Mises stress in plates (198.66 MPa) and screws (237.39 MPa), and lowest value of peak displacement in the whole mandible (260.35 μm), while A + C presented lowest value of maximum von Mises stress in cortical bone surrounding screws (65.96 MPa). For u-HA/PLLA, A + B presented lowest value of maximum von Mises stress in screws (134.15 MPa), and lowest value of peak displacement in the whole mandible (374.43 μm), while A + C presented highest value of maximum von Mises stress in cortical bone surrounding screws (166.41 MPa). The findings suggest that both posterolateral border of mandibular ramus and anterolateral border along sigmoid notch are crucial for ORIF of unilateral mandibular condylar base fractures, whatever titanium or u-HA/PLLA devices. In addition, we speculate that titanium devices of position B could be adjusted backward and downward appropriately, but not for u-HA/PLLA device.