1 Principles topenlarge
The association of the transverse plus posterior wall fracture combines a transverse acetabular fracture with one or more separate posterior wall fragments. The transverse component of this fracture could be transtectal, juxtatectal, or infratectal.
Associated transverse plus posterior wall form the second largest group of
associated fractures. There are two different patterns of injury.
In the first, the posterior wall is much more displaced than the transverse component, with likely posterior dislocation.
In the second, the transverse component is much more displaced than the posterior wall, with typically associated “central” dislocation.
Mechanism of the injury
Posterior wall fractures, whether isolated or associated, are commonly caused by a blow to the flexed knee on the dashboard in a car accident.
Search for associated knee injuries.
2 Joint distraction topenlarge
Traction on the femur, laterally or distally, increases the joint space.
This will help
- expose the joint
- remove loose fragments and
- reduce some marginal impaction fractures
Traction can be applied in several ways, including
- by hand (the “assistant-distractor”)
- with a femoral distractor
- with a traction table
Traction with a femoral distractor
One way to apply traction is with a large distractor. This avoids both constant pulling and use of the fracture table, but does limit mobility of the hip. Properly placed, the distractor may properly realign the femoral head.
Insert a 5 mm Schanz screw into the sciatic buttress proximally. Place a second Schanz screw into the femur at the level of the lesser trochanter.
Tension on the distractor can be adjusted as needed for visualization or reduction
3 Cleaning of the fracture site topenlarge
Exposure and cleaning
The posterior wall and attached capsule are reflected laterally, but additional capsular incisions may be necessary to see well inside the joint. Extraarticularly, the posterior wall fracture surface should be exposed subperiosteally.
Clean and irrigate the fracture site to prepare for the direct reduction.
Remove the loose bodies
Look for loose bodies. Their removal, along with any blood clots, is
essential for adequate cleaning of the joint.
4 Reduction of the fracture topenlarge
Use of a bone hook
A bone hook around the edge of the greater or lesser sciatic notch helps to
assess and reduce the posterior part of the fracture.
First, check the mobility of the fracture by pulling on the hook. Mobility must be sufficient to permit reduction. If it is not, the fracture site should be further cleaned and irrigated.
It is possible to assess the reduction of the transverse fracture component
by moving the posterior wall fragment and applying femoral traction. If the
anterior end of the transverse fracture remains malrotated, a Schanz screw
joystick may help achieve the reduction.
Use of a Farabeuf clamp
Final reduction can be obtained and compressed with a Farabeuf clamp applied to screws. Insert two 4.5 mm cortical screws, one on each side of the fracture, away from the site of definitive fixation. They should be long enough to protrude above the bone for the tips of the Farabeuf clamp. This clamp can also help to improve rotational alignment of the posterior end of the transverse fracture, as well as to close the gap between the fragments.
Use of a Jungbluth clamp
Instead of the Farabeuf clamp a Jungbluth clamp can be used. Its different screw anchorage allows this clamp to either distract or to compress the fracture.
Similarly to the above desription for the Farabeuf clamp, insert one 4.5 mm cortical screw each into
- the posterior column above the ischial tuberosity
- the superior portion of the iliac wing above the acetabulum.
The screws must be parallel to each other and perpendicular to the bone for easy application of this clamp. They should protrude approximately 1 cm above the cortical surface.
The trick to correct malrotation of the transverse fracture is to use a 5 mm
Schanz screw on a T-handle. This is inserted just medial to the ischial
Manipulation of the Schanz screw will help with improving the reduction. The combination of the clamp and the joystick, possibly with additional bone hook manipulation, helps obtain an anatomical reduction.
Free bone fragment
If possible, include any loose bone fragments in the final reconstruction, particularly if they form part of the articular surface.
Reduction of the transverse fracture with Jungbluth forceps
This illustration shows appropriate placement of 4.5 mm cortical screws for the Jungbluth forceps.
Attach the reduction forceps to the screws
The correct orientation (handle lateral to screws) of the Jungbluth forceps protects the sciatic nerve from being stretched.
Do not tighten the screws completely, thus allowing bone fragments to rotate underneath the reduction forceps.
After reduction maneuvers, check the fit of the greater sciatic notch and
the retroacetabular surface by palpation. If a step can be felt along the
quadrilateral surface and pelvic brim, there may still be displacement of the
articular surface of the joint. Several adjustments may be necessary.
Derotation of the distal (ischiopubic) fragment
If the mobile ischiopubic segment remains malrotated, a Schanz screw joystick can be helpful.
The screw is placed in the ischium, between the posterior rim of the acetabulum and the ischial tuberosity. Drill a 3.5 mm hole for a 5 mm Schanz screw directed so the screw handle remains at the edge of the wound. Insert the screw and attach a T-handle.
Once rotation is correct, use pelvic reduction forceps to stablize the reduction and compress the fracture.
This illustration shows the Jungbluth clamp on the posterior column.
One point of a small angled-jaw pelvic clamp has been inserted through the greater sciatic notch onto the quadrilateral surface. The other point is outside the pelvis on the stable proximal fragment. This clamp helps maintain fracture reduction.
5 Lag screw fixation topenlarge
After obtaining anatomical reduction of the transverse fracture, it is initially fixed with two lag screws, one directed across its anterior portion, and the other placed posteriorly.
Anterior screw insertion
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 3.5 mm (or 4.5 mm) cortical screw will be used.
Create a gliding hole with a 3.5 mm (4.5 mm) drill bit, depending upon chosen screw size. This should extend to the fracture line. Continue with the 2.5 mm (3.2 mm) drill bit, aimed towards the pubic ramus. Use an oscillating drill to protect the soft tissues. Insert a screw of the appropriate length. A washer is recommended to avoid sinking of the screw head in soft bone.
Aids for correct screw placement
A finger, inserted through the greater sciatic notch and along the quadrilateral lamina to the obturator foramen, helps to direct the screw. The hip joint may be examined, with lateral femoral head distraction, to avoid placing the screw intraarticularly.
Fluoroscopic confirmation of this screw’s position is essential. During its
insertion, one must remember the proximity of neurovascular structures to the
Posterior fracture reduction
Reassess the reduction of the fracture where it crosses the posterior column, adjusting with clamps if necessary. Reduction must be anatomical, particularly for transtectal fractures.
Posterior fixation - screw
Depending upon the posterior location and orientation of the transverse fracture, it may be suitable for lag screw fixation. Such a screw may be placed from distal to proximal, as illustrated, or from proximal to distal, though this may be difficult with the limited proximal access offered by the Kocher-Langenbeck incision.
Posterior fixation - plate
If it is not possible to fix the fracture posteriorly with a lag screw, a plate along the posterior column, placed medially, very near the greater sciatic notch, is a good alternative. This may be short, as a more lateral plate will be added to support the posterior wall, and this adds additional fixation to the transverse fracture. These screws for this initial plate can be placed eccentrically to help compress the fracture.
Reduction and fixation of posterior wall
This figure shows the wall fragment reduced and fixed with two lag screws after initial posterior column fixation with a plate. Another plate must be added across the wall fracture to obtain secure fixation.
Reduction of a free fragment
This example shows reduction and fixation of a free bone fragment with articular surface. The femoral head has been reduced into the joint by releasing the traction. Reconstruction of the posterior wall began with replacement of the free osteocartilagenous fragment, so that its articular surface is congruent with the femoral head. Next, the wall fragments must be reduced anatomically, and fixed in place. The free fragment will be held reduced by the overlying posterior wall fragments.
Fixation of posterior wall fragments
Reduce the posterior wall fragments, with attached hip capsule. Use a
ball-spike, dental picks, or elevators.
This figure shows the reduced fragments being fixed initially with 3.5 mm cortical screws. If the fragment is large enough, this size screw can be used, but it should be a lag screw, with a 3.5 mm gliding hole drilled in the wall fragment, and 2.5 mm thread hole in the underlying bone. Alternatively, a smaller (2.7 mm) cortical screw may be used. It is important to avoid the joint when placing these screws.
With the patient in the prone position a horizontal orientation of the drill bit helps direct the drill clear of the joint. However, this requires the surgeon’s careful attention and x-ray evaluation of each such screw.
6 Plate application topenlarge
Choice and contouring of plate
There are both straight and curved pelvic reconstruction plates. Sometimes a
curved plate works well on the posterior wall. We illustrate a straight plate
which will be contoured “on the flat” and shaped to fit the contours of the
lateral posterior column. This plate must be contoured and positioned for
optimal support of the wall fragments.
To aid contouring, a malleable template is first fit to the bone. This provides a model for contouring the 3.5 mm reconstruction plate.
The plate is slightly undercontoured, over the convexity of the posterior
column, compared with the template. This is so that it compresses the fragments
slightly as its screws are tightened.
Application of the plate
First fix the distal end of the plate with a screw into its concave bend, just above the superior pole of the ischial tuberosity.
Drill a 2.5 mm hole before insertion of a 3.5 mm cortical screw but do not completely tighten it yet.
Position the plate optimally, and hold it with a ball-spike or hemostat during the next step.
Next, insert the most proximal screw. Drill eccentrically, closer to the proximal end of the hole, so that tightening this screw tensions the plate, analogous to a dynamic compression plate.
Addition of remaining distal and proximal screws should improve final contouring, to provide uniform compression of the posterior wall fragments. The screws in the mid-portion of the plate may need to be omitted because of the underlying hip joint. Each major posterior wall fragment should have a screw, either through the plate and into good underlying bone, or inserted outside the plate.
Examples for completed fixation
This image shows fixation of a single large wall fragment with a lag screw outside the plate, and a tensioned, contoured pelvic reconstruction plate. This plate protects the posterior fixation of the fracture’s transverse component which is fixed anteriorly with the anterior column screw.
This example shows the alternative use of two posterior plates.
The medial one, near the sciatic notch, was placed first to fix the posterior end of the transverse fracture. The second plate fixes the posterior wall component, and adds additional posterior column support. If possible, one additional screw, perhaps in the most proximal empty hole, might be inserted to increase stability of the wall fragment, but it must avoid the hip joint.
This third example, similar to the one above, also uses two posterior
plates, but with separate small lag screws in the posterior wall
Posterior wall fixation is important for maintenance of the fracture repair, and must be individualized, depending upon size and shape of fragments.
7 Pearl: Spring hook plates topenlarge
Spring hook plates, prepared from small fragment one-third tubular plates, can stabilize posterior wall fragments that are too small or too peripheral for lag screws.
Be careful to ensure that the hooks of the spring plate do not impale the labrum and are far enough away from the edge of the joint not to scratch the femoral head.
Cut off the plate
Take a three or four-hole one-third tubular plate. Cut off the tip through a hole.
Bend the ends into hooks
Bend the newly created prongs downwards to create small hooks.
Overbend the hook
The shape of the hook plate should be more convex than the underlying bone, so that tightening its screw compresses the hooks against the fragment to be stabilized.
Proper alignment is achieved by compressing the fragments against the femoral head.
The hooks should not penetrate the hip joint.
Affix the plates
The spring hook plates should extend medially beyond the posterior wall buttress plate. These supplementary plates provide additional buttress support for the comminuted fragments.
The hooks must press on the bone fragments and not into the labrum.