PhD Fekete - SZIE version - 2.2 - Szent István Egyetem

Literature review
Therefore, in the design the sliding feature of the connection has to be carefully taken into
account by keeping it as low as possible, since the more rolling the connection has, the longer it
lasts.
In the knee joint itself, sliding and rolling appears alike, but as long as the connecting surfaces
(cartilages) are intact, a natural balance prevails. Problems arise when – due to an external
trauma or simply to ageing – the natural balance is split and more sliding starts appearing in the
condyles.
If this case is an actuality in someone’s life, then upcoming knee arthritis can be well handled
by means of unicondylar (one-sided implant) or total knee replacements (TKR) (Figure 2.48).
Figure 2.48. Unicondylar (left) and Total knee replacement (right)
Naturally, these knee replacements have to comply with many strict requirements. The three
most important ones are the followings:
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Being able to carry out closely the same locomotion as a normal non-pathological knee,
Relieve pain,
Good rate of survivorship.
Even though that manufacturers and researchers provide more and more studies about the
efficiency and reliability of the current prostheses, failures still occur. Major causes of failure
can be classified as follows:
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Infection of the joint,
Loose components (either femoral or tibial),
Fracture of components,
Wear of the components.
It is considerably difficult to give a complete answer to each segment, since these abovementioned
problems are probably – to a certain extent – dependent on each other. Thus, let us
limit our investigation to the last problem, related to the wear and within that, to the
phenomenon of sliding-rolling.
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