The aim of this work is to investigate the impact of geometry on the mechanical stability of characteristic structural solutions of plates for internal bone fixation using the finite element method (FEM). Based on the realistic construction of plates for internal bone fixation, 3D geometric and FEM models were formed, and then structural analysis was carried out in the CAD/CAE system CATIA V5. Five different types of plates for internal bone fixation were tested under two types of loads: axial pressure and torque in the case of application to the femur. During the structural analysis, stresses and displacements were monitored at characteristic points of the structure. The most attention was paid to the relative displacements of the bone model fragments, because the stiffness of the plates for the internal fixation of the bone was determined based on them. At the end of the paper, the results of all analyzed plates are presented, their mutual comparison as well as the conclusion in which, based on everything done, it was stated which plate would be the most favorable solution for a given case of bone fracture.