Gamma3 Trochanteric Nail 180 - Stryker

Operative Technique
Lag Screw Insertion
Check on the image intensifier during
drilling to monitor the depth of the
drill near the subchondral bone. At
this stage, you should see the tip of the
K-Wire protruding about 6 to 10mm
out of the step drill. This is because
the threaded portion of the K-Wire
was intentionally not included in the
drill measurement. This is to prevent
the drill from penetrating the joint
(Fig. 52) and to ensure that the K-Wire
remains anchored in the subchondral
bone after reaming. Remove the
Step Drill by turning it clockwise and
pulling it backwards.
Fig. 52
The length of lag screw chosen should
be the same as that of the Step Drill
(in this example 100mm). The screw is
then assembled to the Lag Screwdriver
(Fig. 53).
Fig. 53
Lag Screw and Lag Screwdriver assembly
In a case where compression is to be
applied, a shorter Lag Screw length
should be chosen to avoid the end of
it sticking out too far in to the lateral
cortex (see chapter Compression /
Apposition below). Ensure that the
pins of the Lag Screwdriver are in the
slots of the Lag Screw. The end thumbwheel
must be turned clockwise and
tightened using the Ball Tip Screwdriver.
The Lag Screw assembly is now passed
over the K-Wire, through the Lag
Screw Guide Sleeve, and threaded up
to the end of the predrilled hole of the
femur head. Check the end position of
the Lag Screw on the image intensifier.
A double check of the end position is
also possible with the indicator ring
on the Lag Screw Screwdriver when it
reached the end of the Lag Screw Guide
Sleeve.
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