Numelock II Polyaxial Locking System - Stryker

Operative Technique
Preoperative Planning
The surgeon must first determine and
clearly characterize the nature and
extent of the deformity being
corrected. For this purpose, full-length,
standing (long axial alignment) AP
radiographs need to be obtained.
The x-rays must include the hip,
knee and talus, standing in extension.
The x-ray beam should be centered
on the knee in question. It is also
recommended that a standing lateral
view and an anteroposterior view of
the knee bent at 45° be obtained.
These x-rays are then used to classify
the orientation and magnitude of the
deformity to be corrected using
standard methods as described in the
literature. The mechanical axis of the
patient is defined by a line drawn from
the center of the femoral head to the
center of the tibial-talar joint.
The radiographic evaluation is also
used to determine the site of the
osteotomy, the method of correction
(opening or closing wedge)
and positioning of the plate.
General Principles
It is recommended that any osteotomy
be performed on a radiolucent table
to allow visualization of the hip, knee
and ankle. During the procedure,
it is necessary for the surgeon to have
a clear view of the entire extremity
from the iliac crest to the talus.
A choice of incision consistent with the
anatomical region in question is made
by the surgeon, based on personal
experience and patient considerations.
When treating a tibial deformity
with a closing wedge osteotomy,
the tibiofibular joint will prevent
correction unless the fibula or the
tibiofibular ligaments are cut.
One option is to perform an oblique
fibular osteotomy through a small
incision in the proximal middle third
of the fibula.
Step One – Closing Wedge
Osteotomy and Opening
Osteotomy Wedge Sizing
• The Cutting Guide (Ref. No. GCTP)
in conjunction with fluoroscopic
control permits accurate incisions to
be made for closing wedge osteotomies.
The first cut is made parallel to the
joint line without the Cutting Guide.
Insertion of two K-wires may be
helpful in establishing the plane
and location of the first cut.
• After completion of the first cut, the
Cutting Guide’s flange (see Fig. 1) is
placed into this incision. Adjustment
of the graduated scale allows for
precise angulation of the second
cutting line. For right leg osteotomies,
use the side of the scale indicated by
the letter “D.” For left leg osteotomies
use the side of the scale marked “G.”
Note: The “D” represents “Droite”
(Right) and the “G” represents
“Gauche” (Left) in French.
• When performing an opening wedge
osteotomy, a bone spreader can be
used to pry open the osteotomy site
and keep it from collapsing, while
a bone clamp is used to secure the
opposite aspect so that it does not
displace. It is often useful to keep
a small corner of the far cortex intact
to help maintain stability.
• Use the Trial Wedges (Ref. No.
10CALES) to ensure that the correct
angular position is maintained and
also to help open the osteotomy gap.
If bone filler is used, these Trial
Wedges can also help in determining
the correct size and shape of the
actual wedge to be implanted in the
gap. The Trial Wedges are conveniently
held and manipulated into position
with the Holder (Ref. No. PRCAL).
The Trial Wedge is removed after
stabilization of the osteotomy site.
Flange
Graduated Scale
Figure 1
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