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Abstract
Introduction The paper has the following objectives: The obtaining of virtual 3D parameterised models of the menisci; the determination of the stresses, deformations and displacements of menisci for different cases and for different mechanical solicitations, using finite element method.
Methods To obtain the bones cross sections we used a Aura Philips tomograph.
– The obtained images were redrawn in AutoCad over the real tomographies and the drawings were imported in SolidWorks (a parametrical Computer Aided Design software), section by section, in parallel planes. The virtual models of the internal menisci and external menisci were obtained.
– The initial parameters and kinematical and kinetostatical functions of the virtual biomechanical system of the knee joint were established.
– This system was imported in VisualNastran software.
– The virtual models of the internal menisci, external menisci were discretised and analysed using the finite element method.
Results We obtained the finite elements structure of both human knee menisci. Maps for the von Misses stresses, for the displacements, for the deformations and for the deformation energy in normal menisci. In the cases of 1/3 from the volume of the medial menisci is cut and 1/3 from the volume of the lateral menisci is cut, we simulated a virtual meniscetomy. The stresses and the displacements diagrams were also obtained.
Conclusions
For an indemn anatomical knee, the stress in menisci is un-uniform distributed, the zone of menisci body being the most loaded in both cases: extension and flexion.
The deformations in menisci are unequal distributed, the maximum being obtained at the level of the menisci body.
In the knee extension, the deformations are almost twice bigger than the deformations in the case of knee flexion.
The increasing twice of the loading force in the knee joint determines an increasing of stresses with only 20% because of the amortiser role of the menisci.
