Finite Element Analysis of Locked and Unlocked Plate Fixation Methods in Tibial Diaphyseal Fractures

The plate-screw fixation is widely used in the treatment of tibia diaphysis fractures. Also the structural differences such as design variables and the connection type, locked and unlocked fixation, in plate-screw system affect biomechanical behavior of bone-implant structure. In this study, the mechanical effects of locked and unlocked plate-screw fixation systems on bone-implant structures and their effects on healing period were investigated by finite element method. For this purpose, 3D (three dimensional) fractured tibia models were constituted by considering two fracture angle (60° ve 90°) and different callus structures and then, fixations were performed. The obtained models were analyzed under axial load via ANSYS 14.0. In consequence of the performed analyses, it was obtained that locked fixation system provided more stabilization than unlocked fixation system with respect to stresses and displacements on bone-implant structures. It was observed that stresses and displacements increased in the event of fracture angle 90° instead of 60°. Also, it was concluded that the most effective parameter on the bone-implant structure was found that the mechanical properties of callus structure.