Affiliations: [a] Scientific Group ``Synergy'', Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland | [b] Department of Aeronautical & Automobile Engineering, Manipal Institute of Technology, Manipal, India | [c] Department of Mechanical & Manufacturing Engineering, Manipal Institute of Technology, Manipal, India
Correspondence:
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Corresponding author: Mateusz Pawlik, Scientific Group ``Synergy'', Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland. E-mail:mateusz.pawlik@windowslive.com
Abstract: The main aim of this work was
evaluation of the displacements, strains and stresses in components of knee
endoprosthesis by means of Finite Element Method. The semi-constrained knee
endoprosthesis instrumented into femur and tibia bones was chosen for the
analysis. The first step was preparation of full knee endoprosthesis
geometrical model which was developed on a basis of a real model. Using
reverse engineering methods containing 3D scanning and post-processing,
model was obtained and then modified due to analysis assumptions. To carry
out an analysis it was necessary to develop a femur and tibia bone models,
which were obtained from MRI scans. Next a grid for finite-element method
calculations was generated for the geometrical model. Mesh was next
optimized to obtain high quality elements along with simplification of
calculations. Subsequently it was necessary to specify and set the edge
conditions to reflect appropriately the phenomena taking place in the real
system. The system was loaded with axial force from femur proximal joint
surface to tibia distal joint surface in range of 500-2000 N. Calculations
were realized for endoprosthesis components made of chromium alloy for
femoral joint surface part, UHMWPE for plastic sliding bearing and five
different titanium alloys for endoprosthesis femoral part stem and tibial
implant part - Table 1. On a basis of obtained results, the highest values
of reduced stress in endoprosthesis elements were observed in the stems of
both femoral and tibial part. Stress in bone didn't exceed its compression
strength for all of chosen materials. The biomechanical analysis may form
the basis for improving the geometry of analyzed endoprostheses and
optimizing a selection of the mechanical properties of the material used to
manufacture them.
