1 Preliminary remarks topenlarge
In all intertrochanteric fractures, if the fracture line extends distally, a long nail will be necessary. It is preferable for a number of reasons to use a long extramedullary device even though a limited open reduction may be necessary.
In the intramedullary nail shown here a spiral blade device is used 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.
Preoperative planning consists of determining the CCD (center-collum-diaphysis) angle and the inner diameter of the femur from the AP of the normal side with the use of the implant templates. Most often the nail with the CCD angle of 130° is indicated.
Determination of nail diameter
It is important to measure the medullary diameter at the narrowest segment.
The inner cortical edges should line up with the edges of the ruler aperture. The illustration shows 14 mm.
2 Positioning and reduction topenlarge
Helpful instruments for reducing proximal femur fractures include Schanz screws and T-handle, ball-tipped pusher, and larger pointed reduction forceps. All can be used percutaneously.
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. This will distract the fragments and regain length.
The second step is internal rotation. Check each step with the image intensifier.
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.
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.
In the reverse oblique fracture, the proximal fragment is abducted by the pull of the abductors and often will not reduce with traction. This makes a limited open reduction necessary. A pointed reduction clamp is very helpful in reducing the fracture and in maintaining the fracture reduced until fixation is complete.
A pointed reduction clamp is used to reduce the fracture and maintain reduction.
3 Nail entry point and guide wire insertion topenlarge
Determination of the entry point
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.
Take the guide wire for the long 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.
As the lateral deviation of different implants vary, the exact entry point changes accordingly.
Check guide wire position
Insert the guide wire into the femoral shaft and check its position using image intensification. 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.
Distally, it should be at the level of the femoral condyles.
4 Nail insertion topenlarge
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.
In the elderly, ream by hand to avoid damage to the fragile trochanteric shell. In young patients, use power. Remove the guide wire after reaming.
Distal reaming is performed until the diameter of the medullary canal is 1 mm wider than that of the chosen nail.
Introduction of nail
Under image intensification, the nail now is pushed down over the guide wire and advanced into the medullary cavity by gentle hammer blows.
Remove the guide wire.
The long lateral femoral nail has to be inserted with a twisting motion or the femoral shaft will explode.
During insertion of the last third of the nail length, the insertion handle rotates from an anterior to a lateral position. If the nail does not rotate to the lateral position, remove the nail and reinsert with the handle slightly lateral to the sagittal plane.
Monitor nail passage across the fracture and check in two planes to avoid malalignment.
5 Proximal locking topenlarge
Positioning of the guide wire
After the nail has been completely inserted, 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.
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 from the joint.
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 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 out the bone. This prevents unnecessary destruction of the remaining bone stock.
Insertion of blade
Insert the blade over the guide wire to the stop.
Using image intensification, check that the blade protrudes slightly over the lateral cortex.
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 topenlarge
Verification of nail position and distal locking
Before distal locking, the correct position of the nail and the rotation of the femur must be verified.
Distal locking is usually static with two screws. Occasionally, depending on the fracture pattern, dynamic locking may be chosen.
7 Insertion of end cap top
Since most of these devices are not removed, the end cap is not necessary.