PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

Results
0.8
Χ [-]
1
Sliding-rolling ratio of the Biotech TP P/S model
Medial side
Medial side with ligaments
Lateral side
Lateral side with ligaments
0.6
0.4
0.2
0
Flexion angle [˚]
0 20 40 60 80 100 120
Figure 4.23. Sliding-rolling ratio of Biotech TP P/S model: with and without collateral ligaments
By looking at the DePuy prosthesis (Figure 4.21), no sharp difference can be noticed on the
sliding-rolling curves. With or without the collateral ligaments, their magnitude and shape are
almost identical.
The SZIU model shows also no remarkable difference on the medial side however some
deviation can be observed on the lateral side (Figure 4.22). The sliding-rolling ratios, with and
without collateral ligaments, are corresponsive until 60˚ of flexion angle.
Above this certain angle, 5% more sliding appears on the lateral side with collateral ligaments
at 60˚ of flexion angle and 10% more at the end phase at 120˚ of flexion angle.
Regarding the Biotech TP P/S replacement, this prosthesis showed also no concrete evidence
about the effect of the collateral ligaments on the sliding-rolling phenomenon (Figure 4.23). Up
to 105-110˚ of flexion angle the difference is imperceptible, after 110˚ of flexion 8% more
sliding appears on the medial side with collateral ligaments and 4% on the lateral side without
ligaments. Nevertheless, these differences develop in such a short segment (between 110˚ and
120˚ of flexion angle) combined with very low magnitude that this deviation can be safely
disregarded.
As a summary, it can be concluded that except the SZIU model, no concrete evidence could be
observed regarding the effect of collateral ligaments on the sliding-rolling ratios. The more
observable deviation on the SZIU model is very likely attributed to its design, since the
prosthesis at issue is a prototype.
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