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R. Badet, S. Piedade
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Choice of femoral implant
Whatever the type of prosthesis it is very
important to be sure that the femoral implant
doesn’t be:
- Too large to avoid an impingement in front of
the trochlea, causing conflict with the patella
(which is easily controllable fig. 5 a, b).
- Undersize : it must cover correctly the
posterior condyle (fig. 5 c,d).
Trial implants and final implants
The implants must allow a filling of the flexion
gap and extension gap without lateral collateral
ligament tension. The goal in the end of surgery
is to have a small security laxity (of 2 to 3mm
with stress).
Without ligament release, this small laxity is a
good indicator of the absence of overcorrection
in frontal plane (fig. 6).
In the External UNI the result than we can hope
for our patients is generally very good.
Nevertheless a careful selection of patients and
a adapted technicals choices appear decisive to
obtain a optimal clinical and radiological
outcome.
Fig. 4C at 4F - The femoral implant
must be positioned with a control of
the position in all planes:
- In the medio-lateral plane: it is
very important to avoid conflict
with the tibial spine in positionant
the femoral condyle as close to the
middle of the condyle sometimes
on the lateral edge of the lateral
condyle.
- In the sagittal plane: it is very
important to avoid “camber of
condyle”
which
can
lead
punctiform or a linear constraint of
the femoral implant on the tibial
plateau, source of polyethylene
wear and degradation (delamina
tion and creep).
C
D
E
F