Unstable pelvic ring fractures are complex injuries that often have multiple sites of instability. When operatively stabilizing the injured pelvic ring, consideration must be given to deformity, displacement, as well as osseous and soft-tissue anatomy when planning exposure, reduction, and fixation. Indirect reduction tactics including traction, chemical relaxation under general anesthesia, external fixation devices, position changes, and percutaneous screws1–3 can frequently reduce nonarticular fractures of the pelvic ring.4 However, when adequate reduction cannot be obtained by indirect methods, an open exposure may be required.
Previously published classification systems have made an attempt to predict stability of the overall pelvic ring fractures.5 However, predicting dynamic instability with static images can be challenging. Therefore, it is difficult to arrive at a consensus for anterior (ORIF) indications based on classification alone.
Previously published biomechanical investigations can provide guidance for when to operatively secure the anterior pelvic ring in the scenario of an unstable pelvic ring fracture. Simonian et al6 demonstrated in cadaveric specimens that posterior fixation alone is insufficient to provide stability to anterior fractures and that combination of posterior and anterior fixation provides the most stable constructs for operatively managing unstable pelvic ring disruptions.
The decision to secure an anterior pelvic ring disruption with ORIF can best be directed by the injury pattern, the anterior pelvic osseous morphology, displacement, and surgeon experience. We will present specific cases where ORIF of the anterior pelvis may be indicated.
SYMPHYSIS PUBIS DISRUPTION
Perhaps the most common indication for ORIF of the anterior pelvis is a disruption of the symphysis pubis. Disruption of the symphysis pubis usually occurs in combination with a variable posterior pelvic ring injury. Young and Burgess classified this as an anterior–posterior compression injury.7 In their series, they described the pelvic ring injury as occurring as a result of a high-energy force directed to the anterior pelvic ring resulting in a separation of the anterior pelvic ring in combination with an injury to the posterior sacroiliac (SI) joint(s).
Frequently, disruption of the anterior pelvic ring requires an open reduction for direct manipulation of the anterior pelvic ring because indirect methods usually result in inadequate reduction. Once the symphysis is reduced, the anterior pelvic ring can be provisionally secured with 1 of several clamp options.
Most commonly, the symphysis pubis is secured with a plate applied to the cranial aspect of the parasymphyseal region. The plate can be contoured over the pubic tubercles to allow a strategic screw insertion toward the inferior arcuate cortex of the anterior pelvis. In an isolated symphysis pubis disruption, typically a 6- or 8-hole plate is sufficient to span to the pubic tubercles bilaterally. Longer plates can be difficult to contour but may be necessary if pubic ramus fractures accompany the symphysis pubis disruption. Historically, 2-hole plates were found to be inadequate to neutralize rotational forces at the symphysis pubis. Dual plating was historically performed with a cranially applied plate in addition to a plate applied to the anterior surface of the symphysis. This historic trend was believed to help stabilize posterior instability through anterior pelvic instrumentation. Screw fixation alone (without a plate) is often inadequate for the symphysis pubis because of high tensile forces across the pubis and the presence of minimal cortical bone in the anterior pelvic ring.
A 46-year-old man was involved in a motorcycle crash. He sustained a symphysis pubis disruption and an incomplete right-sided SI joint disruption (Fig. 1). The patient was resuscitated and had his pelvic ring operatively stabilized. A Pfannenstiel exposure was used to reduce and clamp the fracture and to apply a cranially based plate. Posterior supplementation was performed with percutaneous iliosacral screws (Fig. 2).
COMBINED PELVIC RING AND ACETABULAR FRACTURES
When combined pelvic ring and acetabular fractures are present, often the pelvic ring instability and/or displacement will affect the stability and reduction of the acetabulum. Priority should be placed on articular reduction when these injuries exist in concert. The surgeon should recognize that the posterior pelvic ring injury may influence the acetabular reduction.8
When multiple points of instability exist in the pelvis, conventional clamp and reduction maneuvers for the acetabular injury may not result in anatomic reduction. Concomitant pelvic ring fractures remote from the acetabular fracture may need to be stabilized to recreate the bony and soft-tissue “hinges” that can assist reduction when clamps are applied in a conventional fashion. If the remote pelvic ring fractures are stabilized before acetabular fixation, care must be taken to anatomically reconstruct those segments to avoid a “summative malreduction” at the level of the acetabulum.
Anterior exposures for acetabular surgery can be used to perform ORIF of ipsilateral pelvic ring fractures. In the case of contralateral anterior pelvic ring fractures, the anterior exposures can be extended, as in the case of a Stoppa exposure, or separate approaches can be created to directly manipulate and instrument the pelvic ring fractures.
A 22-year-old man sustained a right associated both column acetabular fracture and left-sided anterior pelvic ring fractures in a motorcycle crash (Fig. 3). An ilioinguinal approach was used to expose, clean, and reduce the right acetabular fracture. Accurate reduction of the acetabular fracture could not be achieved initially. The left anterior pelvic ring fractures were manipulated directly and secured with medullary ramus screws. Once the left anterior pelvic ring fracture was secured, the right acetabular fracture could be more easily reduced (Fig. 4).
A 37-year-old man who is 4 years status post ORIF of a right posterior wall acetabular fracture presents after a motorcycle collision, sustaining left transverse posterior wall acetabular fracture, symphysis pubis disruption, and bilateral SI joint disruptions (Fig. 5). The patient was placed supine for open reduction of the symphysis pubis and the anterior aspect of the acetabulum fracture, as well as percutaneous fixation of the bilateral SI joints. The patient was placed prone in the same operative setting and a Kocher–Langenbeck exposure was used to manipulate the posterior portions of the left acetabular fracture (Fig. 6).
COMBINED ANTERIOR RING AND SYMPHYSIS DISRUPTION
When pelvic ring disruptions include injuries to the symphysis pubis in addition to other areas of the pelvic ring, ORIF may be indicated. In the discussion of the symphysis pubis above, we discussed that direct reduction of the injury is often necessary to achieve a satisfactory reduction. Occasionally, when multiple anterior ring injuries exist, direct reduction of the symphysis results in indirect reduction of concomitant ramus fractures or other anterior ring disruptions. If satisfactory reduction of the rami is not achieved with direct reduction of the symphysis, further anterior dissection, reduction, and fixation may have to be performed.
A 37-year-old woman was a passenger on a motorcycle when it collided with a motor vehicle. She sustained a symphysis pubis disruption and a right-sided pubic root fracture in addition to bilateral posterior pelvic ring disruptions (Fig. 7). An open reduction of the symphysis pubis disruption and the pubic root fractures was performed. The pubic root fracture was secured with an antegrade medullary screw, and the symphysis pubis disruption was fixed with a cranially applied plate (Fig. 8).
A 42-year-old man was caught in a moving tractor tire and sustained injuries to his pelvic region and bilateral feet. He sustained a right complete SI joint injury with left incomplete SI joint injury. He had an anterior symphysis pubis disruption in addition to a left parasymphyseal superior ramus fracture (Fig. 9). His anterior fixation required direct reduction of the left superior ramus fracture to accurately reduce the pubic symphysis. He also underwent open reduction of his right posterior pelvic ring injury and percutaneous management of his left posterior pelvic ring fracture (Fig. 10).
INADEQUATE CLOSED REDUCTION
Excluding symphysis pubis disruptions, there are very few pelvic ring fractures that cannot be adequately reduced by indirect means. However, in the case of an inadequate indirect reduction, an open reduction may be warranted. Once an open exposure has been performed to achieve reduction, a number of implant options may be available to secure the reduced pelvic ring in place.
A 23-year-old woman sustains a fall from a cliff while hiking. She sustained a disruption of the right SI joint and a fracture of the right parasymphyseal region extending to the pubic root (Fig. 11). Inadequate reduction was achieved with closed means. An open exposure was performed through a Pfannenstiel exposure. The fracture was cleaned, reduced, and clamped. A single provisional lag screw was inserted to maintain reduction (Fig. 12). The final construct consisted of an infrapectineal plate and screws to secure the anterior fracture with percutaneous iliosacral screws to secure the right SI joint (Fig. 13).
The final indication for ORIF may be the presence of osseous morphology that may not safely accept and contain percutaneous screws or other anterior fixation. Simonian et al9 demonstrated that the use of medullary ramus screws in a simple ramus fracture may be biomechanically comparable to plate fixation. However, the use of medullary fixation, especially in pubic root fractures, may be precluded in osseous morphology that will not accept and contain a long screw extending from the supra-acetabular region to the pubic tubercle screw. Wright et al presented their findings and demonstrated that only 20% of superior pubic rami would not accept and contain a supra-acetabular region to the pubic tubericle screw, necessitating other fixation options if anterior instability existed for those patients.10 The treating surgeon must understand that there is heterogeneity in anterior ring morphology and that the need for ORIF of anterior pelvic ring injuries may be driven by osseous morphology (Fig. 14).
Several methods exist to operatively stabilize anterior pelvic ring disruptions. Frequently, the surgeon can arrive at accurate reduction with indirect means often accompanied by some percutaneous fixation strategy. These strategies seem to be increasingly popular with the arrival of appropriate implants, imaging, and improved knowledge in our pelvic surgeon community. It must be recognized however that occasional indications for ORIF of the anterior pelvic ring still exist. The fully competent pelvic surgeon must be able to recognize the indications for ORIF of the anterior pelvic ring and have the ability to execute the necessary operative tactics.
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10. Wright RD Jr, Hamilton DA Jr, Routt ML Jr. What factors affect superior pubic medullary ramus fixation? Paper #197 presented at: The American Academy of Orthopaedic Surgeons Meeting; March 1–5, 2016; Orlando, FL.