Sliding Hip Screw (DHS) for Proximal Femoral Fracture Fixation

Patient Positioning, Anesthesia, and Preparation

• The patient is positioned supine on a traction table.

• Both spinal and general anesthesia are applicable.

• The unaffected leg is elevated on a leg holder to allow use of image intensifier.

Closed Fracture Reduction

1. Before starting reduction, verify that you can get adequate AP and lateral views with the image intensifier. Change the positioning of the contralateral leg if needed.

2. Apply longitudinal traction.

3. After restoring limb length, rotate the leg internally. In hip fractures, the affected limb is usually in external rotation.

4. If adequate reduction is not achieved, prepare for open reduction.

Skin Incision

1. Inspect and palpate the landmarks: the greater trochanter and the shaft of femur.

2. Use a K-wire to define the proximal starting point of incision.

3. Start the incision proximally at the level of, or just caudally to, the most prominent part of the greater trochanter.

4. The incision should run in line with the shaft of femur, between its posterior and middle third, and be approximately 10 to 15 cm long, depending on the height of the planned plate. An incision placed too anteriorly makes it difficult to place a guide wire parallel to the axis of the femoral neck.

Visualize and Open the Fascia to Expose the Bone

1. Use an Adson retractor, two double hooks, or finger retractors to retract the skin and subcutaneous fat.

2. Use a scalpel or electrocautery to advance through the subcutaneous fat tissue. Place the retractor(s) deeper as you progress, in order to maintain optimal visibility, until you reach the fascia.

3. Cut open the fascia starting from the greater trochanter proximally, between the posterior and middle third in coronal plane, using scissors, a scalpel, or electrocautery. Extend the incision distally in line with the fibers of the fascia.

4. Locate the vastus lateralis and retract it anteriorly, in order to expose the lateral cortex of the femur.

5. The lateral circumflex femoral artery and vein may be encountered at the intertrochanteric level and should be electrocauterized if necessary.

If Needed: Open Reduction of the Fracture

In case the closed reduction was suboptimal:

1. If closed reduction does not result in near-anatomical reduction, reduce the fracture openly via surgical exposure.

2. Depending on the direction of the displacement, use a blunt Hohmann retractor or Volkmann bone hook anteriorly under image intensifier for reduction. The displacement is usually located in the calcar region.

3. Occasionally, the lateral fragment, containing the femoral shaft, needs to be retracted laterally before the fragment containing the femoral neck and head becomes reducible.

4. Sometimes the traction and rotation of the lower limb have to be readjusted during instrument-assisted reduction to achieve proper reduction.

5. Be prepared to secure the reduction using instruments before the next step. A bone reduction clamp can be placed to maintain the reduction.

Insert Guide Wire for the Hip Screw

1. Place a K-wire with the blunt end first to determine the anteversion of the femoral neck. Drill a guide wire into the femoral neck using an aiming device. The choice of the aiming device is determined by the angulation between the femoral head, neck, and shaft, i.e. the caput-collum-diaphyseal angle (CCD angle), that should be around 130°. You can measure the patient’s normal CCD angle on the preoperative X-ray image, using the contralateral side as reference.

2. Use the C-arm with AP and lateral views for verifying accurate guide wire placement. It should be in the center of the femoral neck in the lateral view and at the border of the middle and inferior thirds of the neck in the AP view. This step is essential, and it will define the stability of the fixation, so take your time, redoing as necessary, to ensure that the guide wire is accurately placed. Drill the guide wire into the subchondral bone.

Insert the Sliding Hip Screw

1. Measure the length of the guide wire. Depending on the manufacturer, the screw has to be 5 to 10 millimeters shorter than the obtained measurement.

2. Drill a hole for the sliding hip screw.

3. If the guide wire is accidentally removed during drilling, it should be replaced before proceeding to the next step. The screw insertion handle with screw tap helps place the guide wire back into its original place. Verify the placement with image intensifier.

4. In younger patients with good bone quality, tapping of the drill hole facilitates the insertion of the screw and reduces the risk of rotating the femoral head fragment.

5. Place the screw 10 mm from the joint surface using the insertion handle. Depending on the technique guide, decide the rotational position of the hip screw, i.e. parallel to the axis of the femur.

Insert the Plate of the System

1. Slide the plate over the insertion sleeve. Ensure that the collar of the plate sits firmly on the sliding hip screw and that the plate sits on the lateral cortex of femur.

2. Drill and place the screws on the plate. Make sure not to accidentally drill too deep medially after penetrating the medial cortex of the femur, to avoid damage to the deep femoral artery and vein.

3. In general, cortical screws are used for fixing the plate. Alternatively, in cases of poor bone quality, after inserting a cortical screw first, other screws can be used as locking screws, if the plate has this option, in order to prevent implant cut-out.

4. When satisfied, release the traction and rotation of the lower limb.

5. Obtain postoperative X-rays with image intensifier.

Wound Closure

1. Check for adequate hemostasis before closure of each layer.

2. Close the fascia with interrupted X-sutures, Vicryl no. 1, or continuous sutures, PDS no. 1.

3. Close the subcutaneous layer with running absorbable sutures.

4. Close the skin with interrupted sutures or skin staples.