1 General considerations top
Sequence of the treatment
Pre-operative traction will be advantageous if the hip is subluxed medially.
For ORIF of transverse fractures with extended iliofemoral approach, the following surgical sequence is common:
- Joint distraction and removal of incarcerated fragments
- Reduction of femoral head dislocation if not achieved closed on admission
- Assessment of reduction (particularly of the anterior column indirect reduction)
- Fixation of the posterior column
- Fixation of the anterior column
Preoperative templating is essential for understanding the complexity of an acetabular fracture.
When using implants on the innominate bone, it is important to know the best starting points for obtaining optimal screw anchorage (see General stabilization principles and screw directions).
The patient is positioned lateral on a flat top radiolucent table or a fracture table. Typically, a distal femoral traction pin is applied to allow the application of traction and also to stabilize the extremity. The knee is flexed 45°.
The extended iliofemoral approach allows the hip joint to be opened with a capsulotomy, just distal to the labrum. Lateral and/or distal retraction of the femoral head makes it easier to see into the joint.
It also allows the fracture to be seen well on the external surfaces of both the anterior and the posterior columns.
The internal surface of the pelvis can be palpated with a finger in the greater sciatic notch, for further assessment of the reduction.
Unusually for a significant joint, articular reduction of acetabular fractures is indirect. The articular surface of the hip joint is not seen directly. Reduction must be assessed by the appearance of the extraarticular fracture lines and intraoperative fluoroscopic assessment. Some fracture lines are palpated manually but not seen directly such as transverse fracture lines on the quadrilateral plate.
Quality of reduction
Posttraumatic arthrosis is directly related to the quality of reduction - the better the reduction, the greater the chance of a good or excellent result.
AO teaching video: Use of the distractor on the pelvis
2 Reduction top
Femoral head subluxation
If the femoral head has been reduced in a closed fashion, subluxation of the joint to clear bony fragments would be required.
If the head is still dislocated then the joint can be cleaned before reduction.
Reduction of femoral head
To begin the reduction, the femoral head must be replaced congruently under the superolateral articular surface. Traction accomplishes this, and may be aided with a Schanz screw in the femur, or possibly a femoral distractor. Inspect the femoral head for articular surface injury.
Reduction of the fracture can be achieved for both anterior and posterior columns simultaneously under direct vision.
Begin the reduction by cleaning all clot and bone fragments from the fracture plane.
A Schanz screw can be inserted into the ischium to use as a joystick for manipulation of the ischiopubic fragment posteriorly.
A hook inserted through the lesser or greater sciatic notch helps to pull the posterior end of the distal fragment laterally.
Posteriorly, the reduction can be held in place with a Farabeuf or a Jungbluth clamp, or alternatively with pointed reduction forceps.
Anteriorly, pointed reduction forceps are used.
Alternative anterior technique
Another anterior reduction technique involves use of forceps applied to a 3.5 mm screw placed into the distal fragment.
Place the screw before beginning the reduction maneuver. It should be inserted medial to the acetabulum, into the best obtainable bone of the distal fragment. Stay close to the quadrilateral surface, outside the hip joint.
After manipulation of the posterior and anterior aspects of the fracture, confirm that the reduction is truly anatomical. Check the articular surface visually and by palpation within the joint. Also confirm reduction on the internal pelvic surface by palpation through the greater sciatic notch.
3 Fixation topenlarge
Posterior column fixation
An axial posterior column screw provides interfragmentary compression across the posterior part of the fracture. This is inserted from distal to proximal.
A 7.3 mm partially threaded cannulated screw is inserted through a separate stab incision in the buttock crease over a guide wire.
The start point is at the ischial tuberosity, and a finger in the greater sciatic notch is used to guide the wire and screw up the posterior column, exiting at the pelvic brim.
Care is taken to protect the sciatic nerve at the level of the ischial tuberosity.
The use of a screw aids the placement of the posterior wall plate as it increases the freedom of placement of the wall plate.
This is commonly referred to as the “butt screw”.
Anterior column fixation
Similarly, the anterior part of the fracture is compressed with an appropriately placed lag screw.
The anterior screw is placed obliquely from above the greater sciatic notch across the fracture. It is aimed anteriorly towards the root of the superior pubic ramus. The entry point is along the anterior (gluteus medius) pillar of the iliac wing, 3 to 4 cm above the acetabular margin.
A 7.3 mm partially threaded screw is usually used to offer compression of the anterior portion of the transverse fracture.
A 2.8 mm guidewire is inserted along the anterior column before the appropriate length screw is passed over the wire.
Alternative: posterior column plate
An alternative to the posterior column screw is a contoured pelvic reconstruction plate applied over the fracture, along the posterior column. In this case, the anterior column screw is applied first.
4 Radiographic assessment top
Intraoperative confirmation of hardware position
During reduction and fixation, take fluoroscopic images in AP, iliac, and obturator oblique views to confirm reduction and/or screw placement.
To confirm that the screws are extraarticular an image exposed with the fluoroscope’s central ray superimposed on the long axis of the screw is taken.
Final radiographic assessment
After completion of fixation, 3 views (AP, obturator oblique, iliac oblique view) are obtained to confirm anatomical reduction and fixation.
The AP radiograph demonstrates an anatomic reduction and restoration of the iliopectineal and ilioischial lines, the anterior rim, the posterior rim, and the radiological roof.
In this case, a 4.5 mm anterior column screw has been placed. Two interfragmentary posterior column lag screws have been placed (distal to proximal) near the sciatic notch. Two additional interfragmentary screws have been placed more distally on the retroacetabular surface. A six-hole reconstructive plate has been contoured to the retroacetabular surface.
The obturator oblique demonstrates that the anterior column reduction is anatomic and that the anterior column screw does not violate the extraarticular surface.
The iliac oblique demonstrates that the posterior column reduction is anatomic. The distal to cranial interfragmentary lag screws can be seen at the apex of the fracture.
Postoperatively, obtain formal high-quality radiographs of AP and both oblique views.