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Supplement Article

Comparison of the Ilioinguinal Approach and the Anterior Intrapelvic Approaches for Open Reduction and Internal Fixation of the Acetabulum

Archdeacon, Michael T. MD, MSE

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Journal of Orthopaedic Trauma: February 2015 - Volume 29 - Issue - p S6-S9
doi: 10.1097/BOT.0000000000000270



The ilioinguinal (IL) approach was developed by Letournel and Judet1 for open reduction and internal fixation of most anterior acetabulum fracture components. The approach allows access to the entire internal iliac fossa and pelvic brim from the anterior aspect of the sacroiliac joint to the pubic symphysis, including indirect access to the quadrilateral surface. In contrast, the anterior intrapelvic (AIP) approach (also known as the modified Stoppa approach) was introduced by Cole and Bolhofner as an alternative technique for open reduction and internal fixation of the anterior acetabulum. Similarly, this approach allows access to the anterior elements from inside the pelvis with the surgeon standing opposite the fracture pathology.2 Although both approaches can be used or even combined, most surgeons develop their technique with either the IL or the AIP. Thus, the focus of this article is to clarify the advantages and disadvantages of each approach in regard to specific factors encountered during reduction and fixation.

Approach Overviews

The IL approach creates 3 working windows that provide access to the anterior acetabulum elements with the surgeon standing on the side of fracture and working “down and into” the pelvis from above. The first or lateral window provides access to the internal iliac fossa and the anterior sacroiliac joint. This window is bordered medially by the iliopsoas. The second or middle window grants access to the pelvic brim and quadrilateral surface by releasing the iliopectineal fascia (Fig. 1). This window is bordered laterally by the contents of the lacuna musculorum (the lateral femoral cutaneous nerve, the iliopsoas muscles, and the femoral nerve) and medially by lacuna vasorum, which contains the femoral vessels and lymphatics. The third or medial window is medial to the femoral vessels and gives access to the superior pubic ramus and retropubic space of Retzius.

Intraoperative photograph demonstrating the iliopectineal fascia as visualized through the second window of the IL approach.

The AIP approach uses a vertical split in the rectus linea alba as one would do with a Pfannenstiel approach for symphyseal fixation. With the surgeon standing on the opposite side of the fracture, dissection is performed along the retro-ramus and quadrilateral surfaces essentially working “up and under” the rectus muscles and neurovascular structures. In this case, the iliopectineal fascia is released directly from the pelvic brim. This technique provides less direct surgical exposure of the femoral vascular structures while maintaining excellent visualization of the pelvic ring and acetabulum.

In either technique, the vascular anastomoses between the iliac and obturator systems (corona mortis) must be ligated with either vessel clips or suture. This vascular leash, which is most commonly venous, is found on the retropubic surface of the superior pubic ramus approximately 6 cm from the symphysis. With the IL approach, the anastomosis is frequently identified with development of the medial window, whereas in the AIP technique, it is encountered during the retro-ramus dissection (Fig. 2).

Intraoperative photograph showing the anastomosis between the external iliac artery and the obturator artery (corona mortis) as seen from the AIP approach.

Iliac Fossa and Pelvic Brim

Fracture components that extend into the iliac fossa or exit out the iliac crest require a lateral window and thus are best addressed with the traditional IL approach. The AIP does not allow for reduction and fixation of the iliac fossa fractures and high anterior column fractures without a secondary lateral window3 (see Figure, Supplemental Digital Content 1, With this addition, the approaches become much more similar, as the only differentiating factor at this point is the second or middle window. Thus, high anterior column, high anterior column posterior hemitransverse, and most both column fractures will ultimately be best treated through the lateral window of the IL approach to reduce and fixate fracture elements into the fossa or iliac crest.

The fixation for these fracture components usually involves internally rotating the crest component with a downward vector toward the sacroiliac joint. This can be accomplished with a clamp applied at the interspinous notch and a ball spike applied deep in the fossa adjacent to the sacroiliac joint. Once reduced, provisional stabilization is followed by definitive plate or screw fixation. This usually involves a lag screw along the iliac crest or from the anterior inferior iliac toward the sciatic buttress supplemented by a reconstruction plate along the inner table of the iliac crest (see Figure, Supplemental Digital Content 2,

Anterior Column

Once the iliac fossa is reduced, the anterior column is oftentimes simultaneously reduced as the fracture line usually extends down toward the superior ramus. This anterior column reduction can be performed through the second or middle window of the IL approach using a downward-directed vector with a spiked pusher. As the femoral head is frequently medialized or in protrusio, lateral traction applied to the femur can assist the anterior column reduction. Provisional fixation can then be obtained with superior-to-inferior K-wires or definitive lag screws if the posterior column does not require reduction.

Alternatively, reduction through the AIP can be obtained using an angled pelvic clamp to apply a superior-to-inferior vector and medial-to-lateral vector to reduce the anterior column. If the clamp is used, 1 of the tines is placed along the pectineal eminence of the anterior column and the second tine along the quadrilateral surface, the obturator foramen, or into the lesser sciatic notch to achieve this reduction.

Frequently, the distal extension of this fracture line ends in a comminuted fracture along the superior ramus so that provisional stabilization of the reduction can be difficult. A provisional infrapectineal reduction plate can temporarily stabilize the fracture components until a traditional pelvic brim plate can be applied. Another option involves a short lag screw along the superior ramus back toward the ischial spine to provisionally stabilize the anterior column. This screw, if placed, must be confirmed not to violate the hip joint because it can be nearly impossible to remove this screw once the brim plate is applied and fixated.

Posterior Column

When the posterior column is involved, reduction can be achieved through either the IL or the AIP, but the techniques are quite different. Traditional teaching uses the lateral or second (middle) window of the standard IL approach. A collinear reduction clamp can accomplish this reduction by placing the hook component into the lesser or greater sciatic notch with the compression foot of the clamp on the pelvic brim or pectineal eminence, the anterior inferior iliac, or the wing of the ilium. Alternatively, an angled pelvic reduction clamp can also be used with 1 tine along the quadrilateral surface and 1 tine along the pectineal eminence. Stabilization through lag screws from the iliac fossa directed toward the ischial spine or from the pectineal eminence parallel to the quadrilateral surface can fixate the posterior column.

When using the AIP approach, the posterior column reduction can be accomplished by lateralizing the posterior column with a ball spike pusher. This fracture tends to be gapped at the sciatic buttress or adjacent to the anterior column. By directing the spike pusher vector lateral and superior, the posterior column can frequently be reduced. Alternatively, a clamp placed in the AIP window with a tine on the pelvic brim and the inferior tine carefully placed in the greater or lesser sciatic notch or into the quadrilateral surface through a drill hole can facilitate compression of the posterior column fracture.3 Once reduced, the posterior column can be stabilized by directing the lag screw from the pelvic brim somewhat posteriorly toward the sciatic buttress. Frequently, the fracture orientation does not lend itself to this fixation strategy. Alternatively, a posterior column plate placed by the intrapelvic window can stabilize the posterior column components. Posterior column using only the AIP can be difficult, and the addition of the lateral window will often facilitate the reduction and stabilization.

Quadrilateral Surface and Dome Impaction

Oftentimes, the quadrilateral surface can be impacted medially in a protrusion manner or the superior articular dome can be impacted medially and superiorly. Reduction and stabilization of these fracture components by the IL can be very difficult. The AIP provides improved access and a more facile reduction and stabilization options for these fractures. Reduction of the medialized quadrilateral surface is most easily accomplished with a foot plate applied to a ball spike pusher followed by lateralization of the quadrilateral surface. Dome impaction can be reduced with elevators or osteotomes placed above and behind the impaction and reducing to the femoral head as a template.4 These components can then be fixated with either independent lag screws directed medial to lateral or alternatively with an infrapectineal buttress plate (Fig. 3).

Intraoperative radiograph demonstrating stabilization of dome impaction with a medial-to-lateral buttress screw and an infrapectineal plate.

Definitive Fixation

With the traditional IL approach, a long pelvic brim plate from the iliac fossa adjacent to the sacroiliac joint extending toward the pubic body running along the superior surface of the pelvic brim is used. This can be accompanied by iliac wing plates/screws and anterior-to-posterior lag screws either independent or incorporated into the plate (Fig. 4). When using the AIP approach, stabilization often includes a pelvic brim plate and frequently an infrapectineal buttress plate.5 Thus, 2 plates “capture” and lateralize the acetabulum. Recently, novel plates have been introduced that allow fixation of the posterior columns and stabilization of the quadrilateral surface (Figs. 5A–C). Caution must be exercised, as results with these multifunctional implants have not been reported.

Radiographs of standard pelvic brim plating with posterior column lag screws.
A–C, Anteroposterior pelvis and Judet radiographs showing novel implants used to stabilize the posterior column and the quadrilateral surface through the AIP approach.


Clearly, reduction and fixation of anterior acetabulum fractures can be accomplished with either the traditional IL approach or the AIP approach. Ideally, the surgeon is familiar with both approaches and can use the technique that best suits the fracture. As new implants and instruments are introduced and more surgeons become familiar with the approaches, outcomes will hopefully improve with less morbidity.


1. Letournel E, Judet R. Fractures of the Acetabulum. 2nd ed. New York, NY: Spinger-Verlag; 1993.
2. Cole JD, Bolhofner BR. Acetabular fracture fixation via a modified Stoppa limited intrapelvic approach: description of operative technique and preliminary treatment results. Clin Orthop. 1994;305:112–123.
3. Sagi HC, Afsari A, Dziadosz D. The anterior intra-pelvic (modified rives-Stoppa) approach for fixation of acetabular fractures. J Orthop Trauma. 2010;24:263–270.
4. Casstevens EC, Archdeacon MT, d'Heurle A, et al.. Intrapelvic reduction and buttress screw stabilization of dome impaction of the acetabulum: a technical trick. J Orthop Trauma. 2014;28:e133–137.
5. Qureshi AA, Archdeacon MT, Jenkins MA, et al.. Infrapectineal plating for acetabular fractures: a technical adjunct to internal fixation. J Orthop Trauma. 2003;18:175–178.

ilioinguinal; Stoppa; anterior intrapelvic; acetabulum; trauma

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