Introduction INTER-PROSTHETIC DISTANCE

0 downloads 0 Views 1MB Size Report
... Paris Saclay - CNRS, 94235 Cachan, France, & IUT-d'Evry Val d'Essonne, Dep. ... (3) Hand Surgery Department, Strasbourg University Hospital, Fédération de ... the mechanical response of a bi-prosthetic femur with different gap distances ...
INTER-PROSTHETIC DISTANCE EFFECT IN HUMAN FEMUR FRACTURE AFTER HIP AND KNEE TOTAL REPLACEMENT A.Abdelkader (1), D. Elizondo (1), J.P.M Correia (1), N. Bahlouli (1), C. Cluzel (2), S. Facca (1,3) (1) ICUBE Laboratory, University of Strasbourg - CNRS, 2 Rue Boussingault, 67000 Strasbourg, France. (2) LMT, ENS-Cachan, Université Paris Saclay - CNRS, 94235 Cachan, France, & IUT-d’Evry Val d’Essonne, Dep. SGM, 91025 Evry. (3) Hand Surgery Department, Strasbourg University Hospital, Fédération de Médecine Translationnelle (FMTS), 1 Place de l'Hôpital, BP 426, 67091 Strasbourg Cedex, France.

Contact: [email protected]

Introduction Patients with hip and knee joint replacements in the same leg are at risk of inter-prosthetic (IP) fractures. A FE numerical Study was performed for the mechanical response of a bi-prosthetic femur with different gap distances between the two implants tips under combined compression and bending loading with offset boundary conditions. In this first estimation of the capability of the test procedure, firstly the femur bone was modelled as a uniform cylinder to capture the global structural tendency. Several stem lengths were used in the simulations, then a real bone geometry was modelled to capture the effect of the real geometry in the results.

Material and Methods The base of the assembly is to go through loading transfer boxes. The bending moment values and thus the compressive stress values can be managed along the femur bone by choosing different arm lengths in a symmetric or non-symmetric way.

The mechanical behavior of the bone was assumed to be elastic transversely isotropic. The elastic constant values were taken from Peng et al. The contact between the stems and the femur bone was modeled with a rough-type interaction.

• Different values gap between the two stems were considered : 120, 110, 100, 80, 70, 50, 35 and 20 mm. • Simple cylinder and real bone geometry is being used.

• The stems material made in titanium and the boxes in stainless steel. • Elastic transversely isotropic behavior of the bone material

Results Simple geometry Non Symmetric

Symmetric

strains distribution along the cylinder outer surface

Non Symmetric

Different thickness strains distribution

Real Geometry

Results Meshing and FEM Surface strains results at the lateral side of the femur with different gaps

Conclusion & Future work - Strain distribution achieves always a same maximum value with the increase of IP distance. - IP distance don’t have a stress riser effect . - Start experimental tests and evaluate the correlation between numerical and experimental tests. - The effects of non homogenous density distribution along the femur bone will be investigated

DICOM DATA

STL FILEs

References • M. Soenen et al. (2013). • L. Weiser et al. (2014). • Peng et al. (2006)