Executive Editor: Joseph Schatzker, Peter Trafton

Authors: Ernst Raaymakers, Inger Schipper, Rogier Simmermacher, Chris van der Werken

Proximal femur 31-A2 CRIF

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Glossary

1 Preliminary remarks top

Classifying a fracture as an A2.1 fracture means that it is clearly a three-part fracture. enlarge

Beware! Some of these fractures may be unstable, eg, fractures with a large lesser trochanteric fragment.
The definitive decision for the treatment of this fracture will be made after positioning of the patient and reduction of the fracture. Since emergency department x-rays are often of suboptimal quality, verification of the preoperative diagnosis using image intensification is necessary.

The lesser trochanter is the key in the decision making as to the choice of the appropriate fixation device.
A2.1 fractures are three-part fractures. The third part is the lesser trochanter.

Some surgeons consider this fracture to be a stable trochanteric fracture and feel that it can be treated with closed reduction and an extramedullary sliding screw system for internal fixation. If in doubt about the number of parts and stability, resort to a different fixation (eg, DHS with a trochanteric stabilization plate (TSP), or intramedullary fixation).

Note
There are many different designs of extramedullary sliding devices for the fixation of these fractures available. The general concept of their application is shown on the next pages with the AO dynamic hip screw (DHS) which is currently the gold standard.

2 Closed reduction top

Reduction will be achieved by first pulling in the length axis of the leg and by internal rotation of the leg. enlarge

The patient is positioned supine on the fracture table. The ipsilateral arm is elevated in a sling and the contralateral uninjured leg is placed on a leg holder.
Reduction is usually achieved by first pulling in the direction of the long axis of the leg in order to distract the fragments and regain length.

Next comes internal rotation.

The reduction must be checked in both the AP and lateral with an image intensifier. In case the closed reduction should fail, open reduction will be necessary. If an unsatisfactory reduction is achieved (eg, large and displaced lesser trochanter) use an intramedullary fixation device.

3 Guide wire insertion top

To facilitate the insertion of the guide wire for the screw in the axial view an additional guide wire might be placed by hand. enlarge

Technique of insertion

The approach is between the vastus lateralis and the septum. The first step is to position a guide wire on the neck and hammer it into the head. With the C-arm positioned to show the neck axis slide the guide wire along the neck parallel to its axis and gently tap it into the head. With the C-arm in the AP make sure that it subtends the CCD angle (collum-center-diaphysis angle, ie, angle subtended between the femoral neck and shaft axes). This will help you with the insertion of the guide wire for the DHS screw.


The aiming device is chosen according to the chosen CCD angle of the implant. enlarge

Application of the aiming device

Choose the correct aiming device according to the CCD angle of the neck. Check its position in the AP with the image intensifier.


The guide wire is inserted through the aiming device and advanced into the subchondral bone. enlarge

Insertion of guide wire for the screw

Insert the guide wire through the aiming device and advance it into the subchondral bone of the head, stopping 10 mm short of the joint.
Position it so that in the AP it is in the caudal half of the neck, and in the axial view in the center of the neck.

4 Screw insertion top

Determine the length of the DHS screw with the help of the measuring device. enlarge

Determination of the length of the DHS screw

Determine the length of the DHS screw with help of the measuring device. Select a screw which is 10 mm shorter than the measured length.


Adjust the cannulated triple reamer to the chosen length of the screw. Drill the hole for the screw and the plate sleeve. enlarge

Drilling

Adjust the cannulated triple reamer to the chosen length of the screw.
Drill a hole for the screw and the plate sleeve.


When the screw has reached its final position, the T-handle has to be in line with the longitudinal axis of the femur. enlarge

Screw insertion

The correct screw is mounted on the handle and inserted over the guide wire. By turning the handle it is advanced into the bone. Do not push forcefully or you may distract the fracture.

In young patients with hard bone, it is best to use the tap to precut the thread for the screw. Otherwise the screw may not advance, and you may actually displace the fracture by twisting the proximal fragment as you attempt to insert the screw.

When the screw has reached its final position (checked with the image intensifier: 10 mm short of the subchondral bone in the AP and lateral), the T-handle of the insertion piece should be parallel to the long axis of the bone to ensure the correct position of the plate.

5 Plate fixation top

Determine the length of the DHS screw with the help of the measuring device. enlarge

Fixation of the DHS plate

Generally, a four-hole DHS plate with the preoperatively determined CCD angle will be chosen.
Take the plate with the correct CCD angle and slide it over the guide wire and mate it correctly with the screw.
Then push it in over the screw and seat it home with the impactor.


Adjust the cannulated triple reamer to the chosen length of the screw. enlarge

Fixation of the plate

Fix the plate to the femoral shaft with an appropriate number and size of plate holding cortical screws.

Note
There is no need to use the compression screw. As the patient bears weight, the fracture will impact and compress due to the sliding design of the implant.

v2.0 2010-11-14