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Authors of section

Authors

Theerachai Apivatthakakul, Jong-Keon Oh

Executive Editor

Michael Baumgaertner

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Sliding hip screw with trochanter stabilization plate

1. General considerations

Introduction

To support the lateral wall, the dynamic hip screw (DHS) is coupled with the trochanter stabilization plate (TSP), which augments the fragile lateral wall and prevents excessive fracture collapse.

Optionally, the antirotation wire can be replaced by a cannulated screw parallel to the DHS lag screw.

The sliding hip screw is designed to allow controlled collapse. The collapse is limited as the base of the neck comes to rest on the greater trochanter. If the greater trochanter is very comminuted and the lateral wall is involved, control of the collapse is lost. A trochanteric supporting plate (TSP) may be used to restore the supporting effect of these structures.

Fixation of a pertrochanteric fracture with a sliding hip screw and trochanter stabilization plate
Note on illustrations

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

Generic fracture patterns

Closed vs open reduction

Fracture reduction should start with a closed attempt.

If manipulation does not lead to a satisfactory reduction, a percutaneous reduction technique should be performed.

The definitive decision for the treatment will be made after positioning the patient and an initial closed reduction. Since emergency department x-rays are often of suboptimal quality, verifying the preoperative diagnosis using image intensification is necessary.

The pull of the iliopsoas muscle may flex and externally rotate the proximal fragment, and traction will not correct this displacement. In these cases, open reduction is often necessary.

Superolateral displacement of the shaft (right illustration) after high-energy trauma is a sign of an irreducible intertrochanteric fracture and requires open reduction.

The displacement of the medial neck spike causes button-holing anteromedially through the iliofemoral ligament, anterior capsule, and iliopsoas.

Pull of the iliopsoas muscle on the proximal fragment (left illustration) and superolateral displacement of the shaft after high-energy trauma (right illustration) in pertrochanteric fractures

Correct position of lag screw or blade

The thread of the lag screw (or tip of the spiral blade) needs to end in the trabecular bone structures to gain enough purchase. Therefore, it is important that the lag screw comes to lie in the center of the head-neck axis or slightly inferior to it. This allows for increased depth of the screw.

Incorrect lag screw positioning for the fixation of pertrochanteric fractures with a sliding hip screw

Imaging

If the trauma plain films show a potentially unstable fracture but do not give enough detail about the fracture morphology, 3-D CT is a powerful tool for better diagnosis and planning a strategy for a successful surgery.

Implant selection and preoperative planning

Spiral blade vs lag screw

There is not yet a clear indication of when to use a spiral blade and when a lag screw. It is, therefore, often surgeon’s preference.

In a young patient with hard bone, a blade is relatively contraindicated, and a screw should be used instead (with tapping).

In elderly patients, the use of a blade does compact the bone.

Plate length

Generally, a four-hole DHS plate with the preoperatively determined neck-shaft angle will be chosen in combination with a TSP.

Sliding hip screws with a four-hole plate
Barrel length

A plate with a short barrel (illustration on the right) may be used if the lag screw length is ≤ 75 mm to allow for sliding.

A short barrel should only be considered if its end would impinge dense cancellous bone in the head.

Sliding hip screw plate with different barrel length
Neck-shaft angle

For proper insertion of the implant, determine the optimal neck-shaft angle on the basis of the contralateral intact proximal femur. This is usually 130° or 135° depending on the patient.

If this is not available due to previous hip-joint replacement or improper AP view with external rotation of the proximal femur, provisionally reduce the fracture before draping under traction and assess the reduction quality. If acceptable, measure the angle from the AP view after reduction.

Measuring the femoral neck-shaft angle from the AP view after reduction for selection of the correct sliding hip screw implant
Pitfall: If the implant angle does not correspond to the neck-shaft angle, placing the lag screw at the ideal position is challenging. The femoral head tends then to collapse into varus and cut out.
Correct and incorrect implant angle of a sliding hip screw

AO teaching video

Femur, Proximal – Trochanteric Fractures – Stabilization Using the Dynamic Hip Screw (DHS) and a Demonstration Exercise Using DHS in Combination with the Universal Locking Trochanter Stabilizing Plate (ULTSP)

(26 minutes)

2. Patient preparation

Position the patient supine on a fracture table either with the contralateral uninjured leg placed on a leg holder or in a scissors configuration.

For C-arm positioning to acquire optimal AP, lateral, and axial views, read the additional material on:

For treatment of a pertrochanteric fracture, the patient may be placed supine on a fracture table with the contralateral leg placed in a leg holder.

3. Reduction

Closed reduction

Closed reduction is usually achieved by:

  1. Pulling in the direction of the long axis of the leg to distract the fragments and regain length
  2. Adjustment of internal rotation of the femoral shaft ...
Closed reduction of a pertrochanteric fracture with pulling and internal rotation on a fracture table

... until the patella is facing forward on an AP view of the knee joint

AP view of the patella

Check the reduction in both the AP and lateral view with an image intensifier.

C-arm position for an AP view of the proximal femur with the patient supine on a fracture table

Assessment of reduction quality

Read the fracture line on the image intensifier views. Identify gaps or increased density due to overlapping of fragments.

Follow the medial cortical line on the AP view and the anterior cortical line on the axial view. Identify any translational or angular malalignment.

Acceptable reduction quality shows the following patterns:

  • No gap or increased density visible along the fracture line

In the AP view:

  • Continuous medial cortical line
  • No varus angulation

In the lateral view:

  • Anteversion approximately 15°
  • Continuous anterior cortical line

For more details, see the additional material on assessment of reduction quality.

Patterns in AP and lateral view for acceptable reduction of pertrochanteric fractures

Percutaneous reduction

If closed reduction is not satisfactory, carry out a percutaneous reduction technique.

Open reduction

If closed reduction fails, carry out an open reduction through a lateral approach.

Enlarge the lateral incision as necessary by increasing its length and retracting the vastus lateralis anteriorly and medially. Direct visualization of the fracture site is usually unnecessary.

Lateral approach to the proximal femur with a limited longitudinal incision

Clear the fracture site of interposed soft tissue all along the fracture line as needed.

Then restore gross length and rotation with the fracture table.

Place pointed reduction forceps so that one point catches the medial cortex proximal to the lesser trochanter.

Reduction is achieved by closing the forceps. Temporarily maintain the alignment with a 2.0 mm K-wire perpendicular to the fracture line.

Confirm the reduction with the image intensifier.

Reduction of a pertrochanteric fracture with pointed reduction forceps

4. Approach for implant insertion

If the reduction has been performed closed or percutaneous, perform a limited lateral approach with an incision large enough to insert the implant and cortical screws.

5. Guide-wire insertion

Insertion of antirotation wire

To avoid rotational displacement during screw insertion, place an antirotation wire parallel and proximal to the head-neck axis.

If a K-wire used for temporary fixation is in an appropriate position, this can be used instead.

Antirotation wire to avoid rotational displacement of pertrochanteric fractures during sliding hip screw insertion

Application of the aiming device

Place the appropriate aiming device so that the screw trajectory runs through the head-neck axis or parallel and slightly inferior to that on an AP view.

This ensures that the tip of the blade or lag-screw thread ends in the trabecular bone structures.

Check its position with the image intensifier in AP, lateral, and axial views. In all views, the trajectory should be in line with the head-neck axis.

Aiming device positioned for insertion of the sliding hip screw guide wire

Insertion of a guide wire for the screw

Insert the guide wire through the aiming device and advance it into the subchondral bone of the head. Stop the insertion only 5 mm short of the joint. This helps prevent guide-wire pullout during reaming.

Position it so that in the AP view, it is through the center or slightly inferior to the neck and in the lateral and axial view in the center of the neck.

Pearl: If the first attempt of guide-wire insertion ends up slightly anterior to the center, it is challenging to redirect the guide wire to the ideal position because it tends to fall back into the previous track.
Drill the wire in reverse mode and push it forward to redirect the wire to a subtle amount.
Guide and antirotation wire inserted for sliding hip screw application
Pitfall: Failure of fixation increases proportionally to the deviation of the guide wire track from the head-neck axis.
Incorrect guide-wire insertion for sliding hip screw application

6. Screw insertion

Determination of lag-screw length

Determine the length of the lag screw with the help of the measuring device. Select a screw that is 5–7 mm shorter than the measured length.

Determining the lag-screw length for sliding hip screw application

Reaming

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

Slide the reamer over the guide wire and simultaneously drill for the lag screw, ream for the plate barrel, and countersink for the plate-barrel junction.

Note: In case of an unstable fracture pattern, reaming could lead to collapse and joint penetration.
Reaming for insertion of a sliding hip screw with the dedicated triple reamer

Insertion of the femoral neck screw

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

Mount the correct screw on the handle and insert it through the centering sleeve over the guide wire. By turning the handle, it is advanced into the bone. Do not push forcefully to avoid distraction of the fracture.

The antirotation wire may help to avoid rotational displacement.

When the screw has reached its final position – 5–7 mm short of the subchondral bone in the AP and lateral view – the T-handle of the insertion piece should be parallel to the axis of the proximal femur to ensure the correct position of the plate.

Insertion of the femoral neck screw for application of a sliding hip screw

7. Fixation of the DHS plate

Application of the DHS plate

Take the plate with the previously chosen neck-shaft angle, slide it over the guide wire, and mate it correctly with the screw.

Push it in over the screw and seat it home with the impactor.

Application of the DHS plate

Plate fixation

Fix the plate to the femoral shaft with one cortical screw in the second shaft screw hole to maintain the DHS position while applying the TSP.

Remove the antirotation wire.

Note: There is usually 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.
If compression is needed to reduce any fracture gap, the compression screw may be used but needs to be removed after compression to avoid irritation in case of further sliding.
The compression is used and maintained in paraplegics who have no resting joint reaction force, to avoid implant dissociation during patient transfers.
Fixation of a pertrochanteric fracture with a sliding hip screw

8. Application of trochanter stabilization plate (TSP)

Plate preparation

If necessary, contour the spoon-shaped end of the trochanter stabilization plate (TSP) to fit the mass of the greater trochanter. Position the TSP over the DHS plate so that it is securely seated and that the screw holes line up.

Trochanter stabilization plate (TSP)

Plate application

Slide the TSP over the DHS plate through the existing incision.

Application of a trochanter stabilization plate (TSP) over a DHS plate

Fix the plate using the holding cortical screws which connect the plate to the shaft.

Fixation of a pertrochanteric fracture with a sliding hip screw and trochanter stabilization plate

Depending on the fracture pattern, if the TSP does not capture the greater trochanter, a tension band wiring may be added to hold the abductor muscle insertion reduced and securely fixed.

A screw may also be added through the plate into the neck to prevent rotation of the head and neck fragment.

Fixation of a pertrochanteric fracture with a sliding hip screw and trochanter stabilization plate with an antirotation screw

9. Final assessment

Confirm fracture stabilization and implant position on AP, lateral, and axial views.

10. Aftercare

Postoperative mobilization

The elderly patient may start with weight bearing as tolerated with walking aids the day after surgery.

Unrestricted range-of-motion exercises of the hip joint are allowed.

Weight bearing as tolerated with walking aids after treatment of proximal femoral fractures

Pain control

To facilitate rehabilitation and prevent delirium, it is important to control the postoperative pain properly, eg, with a specific nerve block.

VTE prophylaxis

Patients with lower extremity fractures requiring treatment require deep vein prophylaxis.

The type and duration depend on VTE risk stratification.

Follow-up

Follow-up assessment for wound healing, neurologic status, function, and patient education should occur within 10–14 days.

At 3–6 weeks, check the position of the fracture with appropriate x-rays.

Recheck 6 weeks later for progressive fracture union.

Implant removal

Only if necessary (eg, painful irritation), and not before union of the fracture. There is a high risk of a femoral neck fracture.

Prognosis of proximal femoral fractures in elderly patients

For prognosis in elderly patients, see the corresponding additional material.