Executive Editor: Joseph Schatzker, Peter Trafton

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

Proximal femur 31-A1 CRIF

back to skeleton

Glossary

1 Preliminary remarks top

Extramedullary and intramedullary fixation devices are available for unstable type of A1 proximal femoral fractures. enlarge

Introduction

In general, extramedullary and intramedullary fixation devices are available for the treatment of unstable fractures of the proximal femur. Currently, there is insufficient evidence to say which is best.
Fixation with a cephalomedullary device allows immediate full weight bearing postoperatively. However, it is more difficult than extramedullary fixation and more intra operative problems may arise. Immediate weight bearing is a must for the elderly. This justifies the preference for intramedullary devices. The Proximal Femoral Nail Antirotation (PFNA) device is a short intramedullary nail which uses a spiral blade device to obtain fixation in the femoral head, rather than a conventional screw. The operative technique for other cephalomedullary devices is similar, but for details see the manufacturer’s guides.


Extramedullary and intramedullary fixation devices are available for unstable type of A1 proximal femoral fractures. enlarge

An A1 fracture without a distal extension or without another fracture distally can be treated successfully with a short IM nail. Preoperatively check the degree of the anterior bow of the femur on an x-ray of the uninjured extremity. If the tip of the nail comes to lie at the apex of the anterior bow, use a long nail or choose a plate.
We shall demonstrate now the steps for the insertion of a short proximal femoral intramedullary nail (PFNA) .


The CCD angle of the uninjured leg is determined with the radiograph as a guide. enlarge

Preoperative planning

Depending on the implant used, the most appropriate CCD angle has to be determined preoperatively.
Take an AP x-ray of the uninjured leg. Using the preoperative planning template, measure the CCD angle of the uninjured leg (center-collum diaphysis angle, ie, angle subtended between the femoral neck and shaft axes). In most cases an implant with a CCD angle of 130º angle will be appropriate.


The appropriate distal nail diameter is found by placing the radiographic ruler over a radiograph of the ipsilateral femur shaft enlarge

Determine nail diameter

Determine the intramedullary diameter by placing the radiographic ruler over the AP x-ray of the fractured femur. This will determine which nail to use. It has to correspond to the intramedullary diameter of the femur.

2 Positioning and reduction top

The ipsilateral arm is elevated in a sling while the contralateral uninjured leg is placed on a leg holder enlarge

Reduction aids

Helpful instruments for reducing proximal femoral fractures include Schanz screws and T-handle, ball-tipped pusher, and larger pointed reduction forceps. All can be used percutaneously.


The ipsilateral arm is elevated in a sling while the contralateral uninjured leg is placed on a leg holder enlarge

Positioning

The patient is positioned supine on the fracture table. The ipsilateral arm is elevated in a sling while the uninjured leg is placed on a leg holder. It is important to ensure that the ipsilateral hip is in an adducted position. To accomplish this, push the torso 10º to 15º to the contralateral side.


To reduce the fracture first apply traction in the direction of the length of the extremity enlarge

Closed reduction

To reduce the fracture, first apply traction in the direction of the length of the extremity. This will distract the fragments and restore length.
The second step is internal rotation. Check each step with the image intensifier. 

Caution!
Excessive traction, in an attempt to reduce the fracture, can lead to pelvic rotation around the perineal post of the fracture table. When the pelvis rotates, as illustrated, it produces relative abduction of the hip, thus interfering with access to the proximal femoral nail entry site.


To reduce the fracture first apply traction in the direction of the length of the extremity enlarge

“Scissors” positioning

Placing both legs in traction prevents pelvic rotation.
The injured hip is slightly flexed and adducted to allow nail entrance. The hip on the uninjured side is extended and abducted to allow lateral imaging. (The two legs are positioned like open scissors.)

The C-arm is placed beside the uninjured hip. It is helpful to use slightly oblique lateral views to avoid superimposition of instrumentation, or of the patient’s opposite leg.

3 Positioning of a guide wire top

In general, short nails are straight, and therefore, the skin incision should be in line with the femoral shaft axis. enlarge

Determination of the entry point

The short nails are slightly curved anteriorly to correspond to the anterior bow of the femur and have a slight lateral deviation of the proximal part in the AP plane to correspond to the shape of the greater trochanter. The entry  point is usually on the lateral aspect of the greater trochanter.
Make your skin incision in line with the femoral shaft axis and about 5 cm proximal to the tip of the trochanter.


As the lateral deviation of different implants vary, the exact entry point might change accordingly. enlarge

Guide-wire insertion

Take the guide wire for the short nail and insert it just lateral to the tip of the greater trochanter and in line with the middle of the femoral neck, and slightly lateral to a line corresponding to the anatomical axis of the shaft.

Note
As the lateral deviation of different implants vary, the exact entry point changes accordingly.


Insert the guide wire into the femoral shaft and check its position using image intensification. enlarge

Check guide wire position

Insert the guide wire into the femoral shaft and check its position using the image intensifier. Ideally, the guide wire’s position in the femoral shaft should be  central and deviate slightly proximally according to the degree of the lateral bend of the implant in the AP plane. In the axial view it must be in line with the middle of the femoral neck.

4 Reaming and nail insertion top

Using a protection sleeve, insert an appropriate drill bit over the guide wire. enlarge

Opening of the femur

Insert the protection sleeve with its trocar over the guide wire and push it through the soft tissues until it abuts against the greater trochanter. Then withdraw the trocar and insert an appropriate drill bit over the guide wire. Ream out the trochanteric area. Ream by hand in the elderly to avoid damage to the fragile trochanteric shell. In young patients, use power. Remove the guide wire after reaming.

Note
Only in exceptional cases, where the medullary canal is smaller than the chosen nail, it will be necessary to overream the femoral shaft so that its diameter is 1 mm greater than that of the chosen nail.


Using a protection sleeve, insert an appropriate drill bit over the guide wire. enlarge

Pearl: Maintaining reduction during reaming

If the fracture passes through the nail entry site, a medially directed force applied to the lateral trochanteric region helps prevent drills or reamers from displacing the greater trochanteric segment(s) laterally. This allows reaming of a channel for the nail, so that its insertion does not distract the fracture.


In most patients the nail, mounted on the insertion device, can be inserted manually. enlarge

Achieve a neck-shaft axis > 130°

Avoiding varus deformity is important to improve fixation, and to preserve functionally important anatomy. Begin by choosing a nail with a neck-shaft angle of at least 130°.
Tips to correct varus:

  • Advance nail
  • Increase traction
  • Remove guide wire from the femoral head and abduct extremity (this will require modifying its entrance channel).

In most patients the nail, mounted on the insertion device, can be inserted manually. enlarge

Nail insertion

In most patients the nail, mounted on the insertion device, can be inserted manually.


In most patients the nail, mounted on the insertion device, can be inserted manually. enlarge

Use the image intensifier as a help and insert the nail to such a depth that it will allow the blade to be placed through the middle of the femoral neck.

There are many devices now available with various proximal locking options. Refer to the manufacturer’s guides for technical details. 

5 Insertion of blade top

Mount the aiming arm on the insertion device. enlarge

Positioning of the guide wire

Mount the aiming arm for the blade onto the insertion device. Make a small skin incision at the appropriate place. Insert the drill sleeve assembly through the aiming device and advance it through the soft tissues to the lateral cortex.


Mount the aiming arm on the insertion device. enlarge

The ideal position of the guide wire in the AP plane is in line with the axis of the neck and slightly in the lower half. In the lateral view it must be in line with the axis of the neck.
The guide wire is inserted subchondrally into the femoral head. Its tip should end 5 mm proximal of the joint.


Use a measuring device to determine the length of the blade. enlarge

Measuring length of blade

Because the tip of the guide wire was inserted into the subchondral bone, take a blade which is 10-15 mm shorter than the measurement. This will ensure that the tip of the blade will be 10 mm from the joint.


Drilling hole for blade

If you are using the PFNA, insert the 11.0 drill bit over the guide wire and open the lateral cortex to 11 mm. In a young patient, drill the neck with the 11.0 mm reamer to make room for the helical blade. In the elderly, stop once you have opened the lateral cortex. The neck has so little bone that it is best to insert the helical blade by hand over the guide wire without reaming the bone. This prevents unnecessary destruction of the remaining bone stock.


Insert the blade over the guide wire to the stop. enlarge

Insertion of blade

Insert the blade over the guide wire to the stop.
Check under image intensification that the blade protrudes slightly over the lateral cortex.


Insert the blade over the guide wire to the stop. enlarge

The blade has to be locked, and locking has to be verified intraoperatively. The blade is locked if all gaps are closed. If it cannot be locked, it has to be replaced.

6 Distal locking top

Make a stab incision and insert the drill bit using a protection sleeve through the selected locking hole. Drill both cortices. enlarge

Drilling hole for distal locking

Make a stab incision and insert the drill bit using a protection sleeve through the selected locking hole. Drill both cortices.


For 31-A1 and A2 fractures static locking is sufficient. enlarge

Insertion of locking bolt

For 31-A2 fractures static locking is sufficient. This should be inserted according to the producer’s instructions.


The use of an end cap might be considered, according to producer's instructions. enlarge

Insertion of end cap

Use of an end cap might be considered, according to producer's instructions. However, as nearly none of the implants will be removed, this step is generally not necessary.
The final position of the nail is checked in two planes.

v2.0 2010-11-14