Comparação de métodos de fixação em uma osteossíntese aplicada a uma fratura do tipo Hoffa por meio do método dos elementos finitos

Abstract

This monograph aims to carry out a comparative analysis between fixation solutions for orthoses and screws in an osteosynthesis applied to a knee fracture called Hoffa’s. The development is carried out in AISI 316L steel and Ti6Al4V titanium in 5 proposed systems, among them, a straight orthosis with and without auxiliary screws, an “H” orthosis with and without auxiliary screws and a solution with screws only. The models used are provided through a computed tomography of a real bone for greater fidelity of the results. In the methodological process, the software Blender and Meshmixer is used, for proper standardization in the models. To assemble the sets, CAD 3D Solidworks is used. Finally, the execution of the structural simulation is done by Ansys with mesh convergence as a function of the displacement at a point of interest. The loading parameters used are for a critical situation, in which a person descends the stairs. The force obtained on the lateral condyle is 1400 N parallel to the fracture line. Total displacement and relative displacement in the system and the stresses acting on the orthosis and screws are evaluated. The relative interfragmentary displacement is the most significant variable, since with high displacements, fracture consolidation does not occur. From these data, it is verified that the “H” plate system had better performance in relation to the straight plate because it presents smaller relative displacements. Regarding the material, it was found that the titanium systems displaced more than steel, however, titanium has a higher yield stress, which attributes greater safety coefficients to the implant.