Mechanical evaluation for the finite element analysis of intramedullary nailing and plate screw system used in humerus transverse fractures

Aim: This study aims to examine the commonly used plate screw system and intramedullary nailing method in osteosynthesis in humeral shaft fractures in terms of stress shielding using finite element analysis. Material and methods: Images were obtained by computerized tomography (CT) to create a 3D model of the humerus bone. After the CT images were transferred to the ANSYS 2021 R2 program (ANSYS, Inc., Canons-burg, PA), a transverse fracture model was created from the shaft region of the humeral bone meshed to the humerus bone and modeled in the 3D environment. Results: The tetrahedron mesh structure was used for the finite element models in our study. The element size was chosen as 3.5 mm for the bone model and 2 mm for the plate and intramedullary nail models. The node numbers of bone, intramedullary nail, and plate were 91230, 462578, and 581352, respectively. The element numbers of bone, intramedullary nail, and plate were 61350, 311285, and 370350, respectively. Maximum stress values of 260 MPa on the nail and 280 MPa on the plate were detected in this study. Conclusion: Fewer stress values were obtained and stress concentrations were not formed on the implant in osteosynthesis performed by intramedullary nailing. It can be concluded that this study may guide further studies for those focusing on it and may contribute to the development of a more comprehensive understanding of the topic.