Comparative Study of the Fractured Humerus Fixation by Intramedullary Nailing and Compression Plate

Comminuted humeral fractures are usually treated with locking plates or intramedullary nails with satisfactory clinical results. It is important to note that the success of this type of implantation depends on the long-term stability, adaptability and integration of the humeral bone tissue while maintaining a lesser and optimal pressure distribution in the surrounding bone. In this context, the main objective of the present work is to search for rational solutions to reduce and minimize stress concentrations by comparing the fractured humerus fixation using intramedullary nailing and a compression plate. To this end, these implants were designed and implanted in a fractured humerus and analyzed by finite elements using three different types of loadings (axial force, inclined force, and torsional moment). To assess the biomechanical behavior of the different implants, the distributions of von Mises stresses, strains and total displacements in the implants and bones (cortical and cancellous) of the humerus were compared. The numerical results obtained showed that the fixation systems by a locking plate or an intramedullary nail fixed by six screws played a very important role in the absorption and minimization of the stresses, and consequently, the stabilization of the surgical treatment adopted. Indeed, the nailing system gives a lower level of von Mises stress and strain in the cortical and cancellous bone of the humerus compared to the plate model under the influence of axial forces and torques, whereas the compression plate shows the lowest values of stresses and strains in the bone when the applied load is of the inclined force type.