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 modified Stoppa 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 (the anterior column reduction can be direct with this approach unlike with Kocher-Langenbeck, but the posterior reduction is indirect)
- Fixation with a pelvic brim plate
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.
2 Reduction topenlarge
Apply traction to reduce the femoral head under the superolateral fragment. This will also begin the reduction of the displaced ischiopubic fragment by ligamentotaxis.
Traction can be applied in several ways with:
- The use of a fracture table that allows longitudinal and lateral traction
- The intermittent help of an assistant (may be unreliable in long procedures)
Apply longitudinal traction to the lower limb, and lateral traction through the greater trochanter.
Both these forces should be tuned until the best effect is obtained.
In some surgeon’s experience, the use of a traction table post or other traction frame is helpful during this operation.
Excessive traction may limit fracture fragment mobility and interfere with reduction.
Cleaning of the fracture site
Fracture sites are prepared by preliminarily increasing the displacement and then removing early callus and granulation tissue.
Joint distraction is extremely useful to facilitate this debridement.
Preliminary reduction is normally achieved by ligamentotaxis with distal and lateral traction through the femur. This can be augmented by placement of a small bone hook in the lesser sciatic notch. The hook can be used to laterally and anteriorly reduce the lower part of the transverse fracture.
Use of reduction clamps
A combination of techniques used to reduce the anterior and posterior elements of fractures can be used for transverse fractures. As the fracture is a simple pattern, one reduction maneuver will be successful.
More posteriorly placed clamps are usually successful.
Reduction clamps can be placed from the supraacetabular surface to the area of the iliopectineal surface on the inner table of the pelvis in similar positions to those used on the outside of the pelvis through an extended iliofemoral approach.
The most direct technique uses pointed reduction forceps (or Weber clamp) which spans from the pelvic brim to the quadrilateral surface portion of the posterior column.
3 Fixation topenlarge
Fixation with a pelvic brim plate
A contoured pelvic brim plate is used through the Stoppa approach. This plate can be contoured to extend across the low exiting transverse fractures to the pubis, as required by the specific fracture.
The application of the pelvic brim plate fixes the anterior column. Interfragmentary screws through the plate fix the posterior column.
The plate must be long enough to provide adequate fixation above and below the acetabulum. This typically requires extension to the pubic body.
Contouring the plate
The use of a malleable template aids plate contouring.
Because the primary purpose of this plate is to buttress the anterior column, posterior contouring is most critical. For this reason, plate fixation normally starts posteriorly and proceeds anteriorly. Final adjustment of the plate profile can be achieved in situ, due to plate malleability.
Tools for in situ plate contouring include the ball spike for pushing, ...
... and large and small fragment screwdrivers for torsional adjustment.
Apply the contoured plate along the pelvic brim spanning from the innominate bone adjacent to the SI joint to the pubis.
The plate is positioned in the medial iliac fossa adjacent to the SI joint. The cranial most screws are placed proximal to the fracture in an anterior to posterior direction parallel to the SI joint, and typically measures 40 mm in length.
Care should be taken to avoid inadvertent violation of the SI joint.
Interfragmentary screws can be applied through the plate to ensure compression of the fracture and provide additional stability above the acetabulum. Care should be taken to ensure that each screw is placed extraarticularly, as this region is juxtaarticular.
Inferiorly, the plate can be secured to the pubic ramus and the body of the pubis. Distal fixation becomes increasingly important in lower fractures.
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
Once all fixation is in place, confirm the appropriate appearance of AP, obturator oblique and iliac oblique views and check the location of any screw that is placed near the hip joint.
The AP view should be inspected to assure that congruence has been obtained. The femoral head should have the same relationship to the radiological roof, the anterior rim and the posterior rim as on the contralateral side.
The pelvic brim plate should be secured to the intact ilium just lateral to the SI joint. The screws placed in the mid-section of the plate securing the posterior column reduction should be close to the ilioischial line.
If the low anterior column was affected, the obturator foramen profile and symphysis should be inspected to assess the quality of the distal reduction.
The obturator oblique should be inspected to ensure that there is no residual subluxation of the femoral head. The reduction of the anterior column should be assessed.
Iliac oblique should be inspected to ensure that the posterior column reduction is anatomic. The restoration of the iliac wing should be confirmed.
Postoperatively, obtain formal high-quality radiographs of AP and both oblique views.