with Dome Impaction and Quadrilateral Plate Comminution in Older Patients Treated with Open Reduction and Internal Fixation

Fig. 6.1

(a) Preoperative anterior-posterior radiograph demonstrating the anterior column posterior hemitransverse fracture pattern with dome impaction. The arrow demonstrates the dome impaction segment. (Image reproduced by permission from Casstevens et al. [17]). (b) A coronal CT scan of the same patient demonstrating dome impaction. (c) A sagittal CT scan of the same patient demonstrating dome impaction

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig2_HTML.jpg — Fig. 6.2

A sagittal CT scan demonstrating a small anterior column fracture with the subchondral arc attached

Operative Technique

The patient is placed in the supine position on a radiolucent table or fracture table that can accommodate lateral hip traction. General anesthesia is induced and intravenous antibiotics are administered. All bony prominences are padded. The anterior pelvis, flank, and ipsilateral lower extremity are prepped and draped in a sterile fashion. The ipsilateral knee is flexed over a radiolucent triangle or bolster to improve the exposure and relax the psoas muscle and iliac vessels. The modified Stoppa or anterior intrapelvic (AIP) approach described by Cole and Bolhofner [10] and Sagi [11] is utilized for exposure with the surgeon working on the contralateral side of the fracture.

Several elements of this exposure benefit from a more thorough discussion. First, the rectus muscle must be adequately released from its insertion on the pubic body. The insertion is broad and extends distally to nearly the entire anterior surface of the pubis; therefore, fairly extensive release allows the rectus to be “rolled” laterally, thereby improving the exposure, yet maintaining the distal insertion of the rectus tendon. Ideally, the rectus is completely freed from the pubic tubercle allowing a sharp Hohmann-type retractor or AIP-specific pubic tubercle retractor to be placed over the pubic tubercle (Fig. 6.3). The iliopectineal fascia must be released from the pelvic brim and a subperiosteal dissection is then carried out along the retro-ramus surface and anterior column to allow for adequate visualization of the fracture. Care is taken to identify and ligate the corona mortis vessels. This is typically a venous anastomosis between the external iliac system and the obturator system, but it can be arterial at times. We utilize vascular clips as electrocautery may result in aggressive hemorrhage. At this point, a sharp Hohmann or AIP specific retractor can be placed through the joint capsule over the anterior lip of the acetabulum to further retract the contents of the psoas gutter. This is followed by elevation of the iliacus and psoas muscles from the iliac fossa and placement of a retractor in the iliac fossa adjacent to the sacroiliac joint.

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig3_HTML.jpg — Fig. 6.3

A photograph of the anterior intrapelvic approach to the acetabulum. The arrow demonstrates the pubic tubercle retractor placed over the pubic tubercle

The remaining dissection occurs along the quadrilateral surface and posterior column. Thorough mobilization and release of the obturator nerve and vessels facilitates this portion of the exposure. In particular, meticulous dissection of the periosteal sleeve around the obturator neurovascular bundle allows for better mobilization of those structures. Once mobilized from the obturator foramen, this sleeve can be cut to allow it to “fall away” from the obturator neurovascular bundle. This maneuver combined with subperiosteal dissection of the obturator internus muscle will increase the posterior column and quadrilateral surface exposure. This is facilitated with a retractor placed in the true pelvis either adjacent to the ischial spine or carefully within the greater or lesser sciatic notch.

Once adequate exposure has been achieved, a 6-mm Schanz pin is placed percutaneously in line with the ipsilateral femoral neck and correct placement is confirmed with fluoroscopy (Fig. 6.4). This allows for lateral traction of the proximal femur, which relieves the deforming forces of the medialized femoral head. The applied traction will facilitate repositioning the femoral head to its anatomic location so that reduction of the impaction using the femoral head as a template is possible. Fracture fragments and hematoma are then subsequently debrided from fracture lines, frequently by use of pituitary rongeurs and elevators. Once fully exposed, the AIP approach facilitates access to the superomedial-impacted subchondral bone of the acetabular dome. Posterior subchondral impaction can occur in conjunction with superomedial impaction or in isolation (Figs. 6.5 and 6.6). If posterior impaction is present, it is much more difficult to access from an anterior approach.

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig4_HTML.jpg — Fig. 6.4

An anterior-posterior fluoroscopic image of a 6-mm Schanz pin placed percutaneously in line with the femoral neck. Lateral traction can then be applied through the proximal femur relieving the deforming medializing forces so that reduction can be achieved

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig5_HTML.png — Fig. 6.5

(a) A coronal CT scan of a patient with an anterior column posterior hemitransverse fracture with associated iliac wing fracture exhibiting marked dome impaction. (b) A sagittal CT scan of the same patient with associated dome impaction. (c) An axial CT scan of the same patient shows significant involvement of the superomedial aspect of the acetabular articular surface

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig6_HTML.png — Fig. 6.6

(a) A sagittal CT scan demonstrating isolated marginal impaction of the posterior wall. (b) An axial CT scan showing isolated marginal impaction of the posterior wall in the same patient

In our experience, superomedial impaction is most easily accessed by “opening” the anterior column component of the fracture to provide either direct or indirect access to the impaction. As an adjunct, the fractured quadrilateral plate can also be exploited by levering that fracture plane open as well [2]. This often accentuates visualization of the impaction and the femoral head. It should be noted that concomitant fracture of the quadrilateral plate in the setting of dome impaction is common in the elderly patient. In these cases, we prefer to address dome impaction and then proceed with the definitive reduction of the quadrilateral plate.

An anterior column osteotomy can also be employed to provide access to dome impaction [12, 13]. This is particularly useful in cases where the anterior column fracture is very large, and manipulating this component for access is not easily accomplished. The osteotomy is performed at the pelvic brim (iliopectineal line) to access the impacted dome fragments (Fig. 6.7). To accomplish this, a rectangular segment of the pelvic brim that incorporates part of the anterior column fracture is pre-drilled and completed using a sharp osteotome. The bone in this region is robust and amenable to repair following dome disimpaction [14]. Whenever possible, however, reducing dome impaction through the fracture plane is our preferred method.

../images/395168_1_En_6_Chapter/395168_1_En_6_Fig7_HTML.jpg — Fig. 6.7

Illustration demonstrating the anterior column/ilium osteotomy to access dome impaction. In this case, the fracture lines are incorporated into the osteotomy, and the posterior column fracture has been stabilized with lag screws. (Image reproduced by permission from Casstevens et al. [17])

As was previously mentioned, restoring the femoral head to the anatomic position is critical for reduction of dome impaction as the head serves as a template. Again, this is accomplished utilizing fluoroscopy while carefully adjusting the lateral traction applied to the hip and “tuning” that position until it is deemed anatomic (Fig. 6.8). Working through the fracture lines or osteotomy site, periosteal elevators, osteotomes, and bone tamps are all utilized in order to reduce the dome marginal impaction. It is important to position the reduction tool in a manner that maximizes the volume of cancellous bone between the elevator and subchondral arc in order to prevent violation of the joint surface with the tool (Fig. 6.9). During the reduction, fluoroscopy is employed liberally as identification of the exact position for a reduction tool often requires multiple images in slightly different planes. Once the reduction tool appears adequately positioned, it is levered carefully against intact bone stock forcing the impacted segment toward the femoral head, again to guide reduction of the articular surface. Occasionally, this can be visualized directly via the working portal through the “opened” fracture lines. We have found that often several attempts may need to be made to achieve appropriate reduction. Collinge et al. suggest that in patients with osteoporotic bone, effort should be taken to achieve reduction within one or two attempts as continued manipulation may result in osteochondral fragments that are not conducive to screw fixation [14]. Dome impaction resulting in multiple small fragments represents a particular challenge for achieving anatomic reduction. In these situations, we attempt to achieve the best articular reduction possible while maintaining hip stability; however, this may be an indication for combined acetabulum ORIF and total hip arthroplasty.