Executive Editor: Chris Colton

Authors: Peter V Giannoudis, Hans Christoph Pape, Michael Schütz

Femur shaft 32-A3 External fixator (subtrochanteric)

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Glossary

Author: Dankward Höntzsch

1 Note on illustrations top

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Throughout this treatment option illustrations of generic fracture patterns are shown, as four different types:

A) Unreduced fracture
B) Reduced fracture
C) Fracture reduced and fixed provisionally
D) Fracture fixed definitively

2 Principles of modular external fixation top

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The modular external fixator is optimal for temporary use. It is rapidly applied without need for intraoperative x-rays and can be adjusted later.

Details of external fixation are described in the basic technique for application of modular external fixator.

Specific considerations for the femur are given below.

3 Pin insertion (femoral shaft) top

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Initial reduction

Prior to pin insertion, it is advisable to correct by manual traction any rotational deformity as well as any overlap of the fracture fragments. By maintaining axial traction, it will be possible to optimize pin placement, thereby facilitating the subsequent reduction maneuvers.


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Iliopsoas muscle forces

Be aware of the pull of the iliopsoas muscle which flexes and rotates the proximal fracture segment. In addition, the glutei may abduct the fragment.


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The Illustration shows the flexed and externally rotated proximal fracture fragment.


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Pin placement

For safe pin placement make use of the safe zones and be familiar with the anatomy of the femur.

The safe zone for the femur is lateral. In temporary external fixation, the pins should be placed so that they do not interfere with planned later definitive fixation; this may mean placing femoral pins a little anteriorly.


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Soft-tissue dissection

In the midshaft region blunt dissection of the soft tissues and the use of small Langenbeck retractors will minimize muscular damage.

Using a straight clamp, prepare a channel for insertion of the pin.


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Blunt dissection of the soft tissues in the trochanteric region is simpler as there is no muscle here.


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Pin insertion

The most proximal pin is inserted through the greater trochanter slightly inferiorly. Its correct insertion and placement is essential for the stability of the proximal segment.

Pearl: insert only two pins initially
When applying three pins in each fragment, insert only two pins initially and link with a rod fully loaded with three clamps. After tightening the clamps on the initial two pins, insert the third pin through its relevant clamp. If all three pins are inserted at once, it may prove impossible to link all three to the tube, if they are in slightly different alignments.

4 Frame construction / reduction and fixation (femoral shaft) top

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To increase frame stability a neutralization rod should be added.

5 Potential postoperative complications top

Loss of reduction

In cases of delayed conversion of the external fixator to a definitive fixation, check x-rays are advisable within the first week and regularly thereafter, to ensure that the quality of reduction has been maintained.


Compartment syndrome

Close monitoring of the femoral muscle compartments should be carried out, especially during the first 48 hours, to ensure that compartment syndrome requiring decompression by urgent fasciotomy, has not developed.

v1.0 2007-12-02