Fracture of femoral neck: Analysis of new implant models with a slit and without a slit by the finite element method

Abstract

During fractures of the neck of the femur (PBHB) for the completion of postoperative fusion, there is a need for stable fixation - interfragmental immobility. The stability of used implants in a living person is difficult to calculate. For this purpose, the analysis is carried out using the finite element method (the final analysis of the limited elements). The aim of this study is to study the features of the proposed new hip implant with finite element analysis. Based on the digital geometry of the anatomy of the femur, a 3D model of the femur was developed. Stress and strain, obtained with the help of the computer program ANSYS as a result of loads on the head of the thigh, were investigated by the finite element analysis method. Based on the Pawel classification, 3 groups of femoral neck fracture models were created, corresponding to the fracture angles closer to 30, 50 and 70 degrees (type 1, type 2 and type 3). In each group, the corresponding implants are analyzed in 2 types: without a slit and with a slit. For the spongiform bone, the UTS (Ultimate Tensile Stres) is defined as 20 MPA, and for the cortical bone, 150 MPA. In all analyzes, the force loaded in the vertical direction onto the head of the computer model of the femur was calculated to be 4000 N. Given that the slits on the surface of the implant can cross waves, homogeneously distribute the force and pressure throughout the entire implant, on the basis of this, a decrease in pressure on the surface of the bone tissue was observed. It is believed that this process can increase the stability of the implant and minimize the level of damage to the bone tissue.