Assessment of the ultimate load on femur with reinforcing implant in the proximal part

M. Nikolaitchik, A. Matveev, S. Bosiakov

Abstract: The tubular bone attenuation due to osteoporosis or benign tumors is an indication for the application of prophylactic implantation with metal structures in certain regions of the femur. To prevent fractures in the proximal femur, external fixators with nails are most often employed.
The aim of this study is to assess the ultimate load on the femur under the action of a person’s own weight after fixation with intramedullary nails based on a finite element modeling. Three fixation cases were simulated, including an auger, a corkscrew and a spoke, attached in the proximal femur part. The finite element model of the femur is reconstructed based on CT-images. The elastic modulus, the shear modulus and the Poisson's ratio of cortical bone varies nonlinearly along the anatomical axis of the femur. The load along the biomechanical axis of the femur is applied to simulate the action of a person's own weight. Assessment of the ultimate load on was carried out using the finite element damage parameter.
Finite element modeling is predicted an increase of the ultimate load on the femur by about 10% after plating the auger or spoke; the ultimate load increased approximately 20% after the utilizing of the corkscrew. Therefore, the most effective to prevent a fracture in the proximal femur with osteoporosis or benign tumors is the application of a corkscrew.


Series on Biomechanics, Vol.32, No.4 (2018), 5- 10

Keywords: crack initialization; finite-element modelling; Human femur; nail implant; ultimate load

Date published: 2019-02-01