Authors of section

Authors

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

Executive Editors

Joseph Schatzker, Peter Trafton

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MIO - Sliding hip screw with plate

1. Preliminary remarks

Beware! Multifragmentary pertrochanteric fractures may be unstable, particularly if the number of intermediate fragments is larger. Stability is also reduced if the greater trochanteric mass is involved in the (four-part) fracture or the fracture line extends well (>1 cm) below the lesser trochanter.
Because these fractures are considered unstable (loss of the lesser trochanter which is important for weight transfer, and loss of greater trochanter which allows collapse of the fracture and foreshortening of the neck), extramedullary devices are considered as a second choice for fixation. They lack the necessary stability to ensure union in a satisfactory position of all the fragments.

Note
The extramedullary devices are unsuitable for the fixation of these fractures because they allow axial collapse under repeated loading. The next pages will show the use of an extramedullary device (DHS) coupled with the trochanter stabilization plate (TSP) which adds to the stability of the fixation and prevents axial collapse.

mio sliding hip screw with plate

Teaching video

AO teaching video: The sliding hip screw

2. Closed reduction

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.

Reduction will be achieved by first pulling in the length axis of the leg in order to distract the fragments and regain length.

3. Insertion of the guide wire

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 of the neck (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.

In order to facilitate the insertion of the guide wire for the screw, an additional guide wire first might be placed by hand.

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

Insertion of the 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.

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

4. Screw insertion

Determination of the length of the DHS screw

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

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

Drilling

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

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

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.

The selected screw is mounted on a handle and inserted over the guide wire.

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, 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.
The plate is fixed with one cortical screw to the femur shaft.

Generally, a four-hole DHS plate with the preoperatively determined CCD angle will be used.

5. Internal fixation

Preparation of the Trochanter Stabilizing Plate (TSP)

If necessary, contour the spoon-shaped end of the Trochanter Stabilizing Plate to fit the mass of the greater trochanter. Position the TSP over the DHS plate in such a way that it is securely seated and that the screw holes line up.

If necessary, contour the spoon-shaped end of the Trochanter Stabilizing Plate to fit the bone.

Application of the TSP

Now the TSP is mounted over the DHS plate and is fixed using the holding cortical screws which connect the plate to the shaft.
Depending on the fracture pattern, if the greater trochanter is not captured by the TSP, 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.

Now the TSP is mounted on the DHS plate and fixed using the holding cortical screws.

Note

The compression screw for the DHS should not be used.

The compression screw for the DHS should not be used.

6. Postoperative treatment

Theoretically, because multifragmentary pertrochanteric fractures are unstable under load and may collapse, weight bearing should be withheld and non or partial weight bearing ordered. Most elderly patients are not able to follow these orders and will load the injured limb. Therefore, if the fracture is very unstable, an intramedullary device is preferred.

Follow-up

The first postoperative visit is at 6 weeks. Check the position of the fracture with appropriate x-rays. See the patient at six-week intervals until union of the fracture and then as desired.

Implant removal

Only if necessary, and not before union of the fracture. Allow usually a minimum of 6 months before removal.

Prognosis of proximal femoral fractures

After surgery the outcomes of greatest concern are
  • mortality
  • loss of independence
  • loss of mobility
  • residual pain.

Mortality
Mortality generally occurs within the first six months after fracture; studies have shown that these rates range from 12-37%.
Predictors of higher mortality rates are patients who are:

  • older
  • male
  • have other comorbid conditions (such as cardiac failure, diabetes, and chronic air flow limitation)
  • have cognitive disorders.

For more information see the additional material on perioperative care in elderly hip fracture patients.

7. Case

In a four part fracture a DHS alone will often fail. Thus, the trochanteric stabilization plate may be added to the DHS side plate to provide further support of the greater trochanter.

A case showing the application of a DHS alone for a simple two-part fracture is shown in the DHS procedure. Here we will only focus on the application of the additional plate in a complex fracture.

AP pelvis of multifragmentary proximal femoral fracture.

AP pelvis of multifragmentary proximal femoral fracture.

Carefully reconstruction with K-wires holding multiple fragments reduced, and with a DHS guide wire placed centrally in the femoral head in both views.

Carefully reconstruction with K-wires holding multiple fragments reduced, and with a DHS guide wire placed centrally in the femoral head in both views

Dynamic hip screw and lateral side plate have been applied, with K-wires still in place, stabilizing some of the fragments.

Only one screw has been inserted into the plate, in the second hole from the top.

The trochanteric stabilization plate will lie over the DHS plate, and the remaining screws will be inserted through both plates.

Dynamic hip screw and lateral side plate have been applied, with K-wires still in place, stabilizing some of the fragments

Trochanteric stabilization plate in place held with a K-wire.

Trochanteric stabilization plate in place held with a K-wire

Screws going into the trochanteric side plate through the DHS side plate to secure the two plates together to the bone.

Screws going into the trochanteric side plate through the DHS side plate to secure the two plates together to the bone

Trochanteric small fragment screws being inserted.

Trochanteric small fragment screws being inserted

AP X-ray intraoperative showing greater trochanter being held by trochanteric stabilization plate and screws.

AP X-ray intraoperative showing greater trochanter being held by trochanteric stabilization plate and screws

Lateral intraoperative image with excellent reduction of the multifragmentary proximal femur fracture with side plate in place.

Lateral intraoperative image with excellent reduction of the multifragmentary proximal femur fracture with side plate in place

Final view of trochanteric stabilization plate in place covering DHS side plate, supplemented with small fragment screws and a wire.

Final view of trochanteric stabilization plate in place covering DHS side plate, supplemented with small fragment screws and a wire

Intraoperative views of final reduction construct.

Intraoperative views of final reduction construct

Final AP and lateral X-rays of well reconstructed multifragmentary proximal femur fracture.

Final AP and lateral X-rays of well reconstructed multifragmentary proximal femur fracture