PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

a) The tibia plateau is a flat surface,
Literature review
b) The surface of the femoral condyle is circular,
c) Ligaments are one-dimensional bodies without mass and they are connected to the bone
by revolute/pin joints,
d) Ligaments can change in length, but only in case of tension,
e) No penetration of the tibia or femur is allowed,
f) No friction is assumed.
As for the findings, the author published the following results:
I. Strain values of the various ligaments as the function of flexion angle.
II. The slip ratio has been calculated as a function of flexion angle (Figure 2.52).
Slip ratio [-]
6
Chittajallu and Kohrt
5
4
3
2
Flexion angle [˚]
0 20 40 60 80 100 120
Figure 2.52. Slip ratio [Chittajallu and Kohrt, 1999]
The remarks related to the results of this model are the followings:
- Although Chittajallu and Kohrt [Chittajallu and Kohrt, 1999] reported that their slip ratio
corresponded well with the result of O’Connor et al. [O’Connor et al., 1990], the result
lacks providing an easily understandable physical meaning regarding the phenomenon
- Their model is far too simple to give an accurate prediction about the sliding-rolling
phenomenon due to the applied geometrical simplifications.
- The model is only two-dimensional.
Ling et al. [Ling et al., 1997] introduced a similar model in order to study the behaviour of a
knee joint with the effect of inertia, articular surfaces, and the patella (Figure 2.53).
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