Sign IM Nail and Interlocking Screw System Technique Manual page 32

Proximal interlock can be done through lateral to
medial or anterior to posterior direction, figure 5.
They are equally stable.
Fig. 5
The proximal end of the nail should be 3mm higher
than the cortex of the greater trochanter, figure 5.
This adds to the stability of the nail as well as makes
removal easier.
Distal interlock
The final location of the
Fig. 6
slots will vary depending
on their location in the
canal. If the end of the nail
is in the narrow part of the
canal, the slots will be
central, figure 6.
If nail ends in the wide part
of the canal, the slots will
be anterior, figure 7. The
Fig. 7
SIGN nail does not have
an arc of radius and the
femur is curved.
Recognizing this
difference will determine
where the pilot hole is
made. The pilot hole
would be made in the center of the femur if the slots are in the narrow part of the canal and anteriorly
in the wide part of the canal. The incision for interlocking should be large enough so you can feel the
cannula on the bone to determine its location. Sometimes the target arm must be adjusted to account
for this. Loosen the distal cap screws to make this adjustment rather than bending the target arm.
NOTE: See page 20 for tips on interlocking.
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