Romanian Journal of Morphology and Embryology 2005, 46(4):279–281
The generation of the three-dimensional model
of the human knee joint
D. POPA1), D. N. TARNIŢĂ2), DANIELA TARNIŢĂ3) D. GRECU4)
1,3)
2,4)
Department of Applied Mechanics, Faculty of Mechanics, University of Craiova
Department of Anatomy, Faculty of Medicine, University of Medicine and Pharmacy of Craiova
Abstract
In this paper we analyze the anatomic elements that compose the human knee joint. Also, we build the spatial model of the human
knee joint components. This study is necessary for the design of prosthesis elements and for the establishment of the necessary
prosthesis technique.
Keywords: human knee joint, three-dimensional model.
Introduction
The knee joint is an important articulation of the
human locomotor system and it is made up of bones,
ligaments, tendons and cartilages.
This is the reason why this articulation is the most
complex of the human body, studies being, thus, truly
difficult to make, even when the analyzing is done in a
motionless position.
The knee is made up of bones, ligaments, tendons
and cartilages. The elements of the knee joint are shown
in Figure 1.
The most important bones are:
▪ the femur – the longest bone of the thigh;
▪ the tibia – the longest bone of the lower leg;
▪ the fibula – the smallest bone of the lower leg.
The knee joint system is shown in Figure 2.
Material and method
The four bones of the knee joint (the femur, the tibia
and the fibula and the knee cap) were analyzed [1, 2].
For the generation of the virtual three-dimensional
model of the knee joint, three main bone components
were analyzed: the femur, the tibia and the fibula.
They are shown in Figure 3.
In order to be able to generate the model,
SolidWorks was used, which is a third generation
CAD program [3].
On the measurements of the bone components and
by using the identification of the simple components
forms, we were able to go on with the three-dimensional
generation for every component alone.
Because SolidWorks is a generating program that
uses parameters, any dimension can be later on
modified.
Results and discussions
Figure 4 shows the four three-dimensional models of
the bone components, by using parameters. The mass
properties were used in generating the first model, so
the virtual femur is almost identical to the real one from
the inertial point of view.
By using the Tools/Mass Properties, we obtained
a 455.46 g femur with the medium density of
0.00056 g/mm3. At the three-dimensional model of the
tibia, for a density of 0.00146 g/mm3, we obtained a
weight of 310.02 g, almost identical to the real studied
bone.
The final model for the fibula had 0.001785 g/mm3
density and a weight of 60.03 g, so it can be considered
similar to the real one, from the inertial point of view.
For a 0.0013 g/mm3 density for the knee cap, we
obtained a weight of 22.38 g.
The models of the bone elements were computer
assembled and taking into consideration the positions
and the anatomical and mechanical axes, the knee joint
was generated [4].
The model only contains the bone components to
which the theory of the rigid solid was applied.
Other elements, like ligaments, meniscus, tendons
and muscles were considered elastic elements or
dampers, conducted or conductible elements with
specific experimentally discovered laws or already
known ones [5].
Conclusions
The obtained model uses parameters completely,
so it can be adapted by modifying any specific
dimensions. Also, by using average densities, the model
is almost identical to the real one, from the inertial point
of view, and by taking the movement laws in a
simulated environment into consideration; the model
develops the entire cinematic characteristics and applies
variation laws to every bone [6–8].
References
[1] BENDJABALLAH M. Z., SHIRAZI-ADL A., ZUKOR D. J.,
Biomechanical response of the passive human knee joint
under anterior-posterior forces, Clin. Biomech (Bristol,
Avon), 1998, 13(8):625–633.
[2] PIOLETTI D. P., RAKOTOMANANA L. R., BENVENUTI J. F.,
LEYVRAZ P. F., Viscoelastic constitutive law in large
deformations: application to human knee ligaments and
tendons, J Biomech, 1998, 31:753–757.
[3] ***, Solidworks 98 Plus User’s Guide, SolidWorks
Corporation, U.S.A., 1998.
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[4] SPANU C. E., HEFZY M. S., Biomechanics of the knee joint in
deep flexion: a prelude to a total knee replacement that
allows for maximum flexion, Technol Health Care, 2003,
11(3):161–181.
[5] TARNIŢĂ D. N., TARNIŢĂ DANIELA, GRECU D. et al.,
Considerations on the complications appeared in cases
of menisci ruptures operated through arthroscopy,
th
The 4 Central European Orthopedic Congress, Dubrovnik,
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[6] ***, Parametric system CAD/CAE for the determination by
simulation and analysis of the mechanical and kinematical
parameters of human knee joint for prosthesis,
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CNCSIS grant, 2 commission, code 282.
[7] POPA D., TARNIŢĂ DANIELA, TARNIŢĂ D. N. et al., The threedimensional model of the femur prosthesis component,
The International Symposium “Biomaterials and Biomechanics”,
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[8] TARNIŢĂ DANIELA, POPA D., TARNIŢĂ D. N., PREOTEASA T.,
Study of the three-dimensional model of the human knee
joint, The International Symposium “Biomaterials and
Biomechanics”, Essen, 2005, 34.
Mailing address
Dragoş Popa, Assistant Professor, Ph. D., Department of Applied Mechanics, Faculty of Mechanics,
University of Craiova, 165 Calea Bucureşti, 200 620 Craiova, Romania; Phone +40251–544 621,
Fax +40251–454 503, E-mail: [email protected]
Received: October 15th, 2005
Accepted: February 20th, 2005
The generation of the three-dimensional model of the human knee joint
Figure 1 – The elements of the knee joint
Figure 2 – The knee joint system
Figure 3 – The femur, the tibia and the fibula
Figure 4 – Three-dimensional models
Figure 5 – The virtual model of the
human knee joint bones
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