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Combined Pelvic Ring Disruption and Acetabular Fracture

Outcomes Using a Sequential Reduction Protocol and an Anterior Subcutaneous Pelvic Fixator (INFIX)

Vaidya, Rahul, MD, FRCSc, FAOA*; Blue, Kevin, MD*; Oliphant, Bryant, MD*; Tonnos, Fred, MD

doi: 10.1097/BOT.0000000000001416
Supplement Article

Objective: The purposes of this article were to (1) compare our combined pelvic ring and acetabular fracture patients' rate of mortality and Injury Severity Score (ISS) to those of patients with isolated injuries at our center and to those with combined injuries as reported in the literature, (2) describe our treatment algorithm using the INFIX for these combination injuries, and (3) report our patients' radiographic and functional outcomes.

Design: Retrospective IRB-approved case series and literature review.

Setting: US Level 1 Trauma Center.

Patients/Participants: Thousand six hundred ninety-seven with acetabular or pelvic ring injury, 174 patients with combination pelvic ring acetabular injuries, and 39 patients with 41 acetabular injuries treated with a surgical protocol.

Intervention: Pelvic ring reduction using INFIX and posterior fixation followed by acetabular reduction fixation. Anterior injury fixed with INFIX.

Main Outcome: Mortality, ISS, pelvic reduction by Keshishyan index, acetabular reduction by the Matta criteria, and functional outcome by the Majeed score.

Results: Mortality was 5.7% and ISS was 12.5 for 174 combined injury patients. In the 39 patients with 41 injuries, excellent pelvic reduction was found in 39, and acetabular reduction was anatomic in 25 (61%), imperfect in 12 (29%), and poor in 4 (10%). Clinically 78% of the patients had good or excellent outcome and 22% had a fair or poor outcome. Nonanatomic acetabular reduction, persistent sciatic nerve palsy, and heterotopic ossification associated with poor clinical outcome.

Conclusions: Our treatment protocol resulted in excellent pelvic reduction, anatomic acetabular reduction in 61% of patients, and 78% good to excellent clinical outcome.

Level of Evidence: Case series Level IV.

*Detroit Medical Center, Wayne State University, Detroit, MI; and

Detroit Medical Center, Michigan State University, Detroit, MI.

Reprints: Rahul Vaidya, MD, FRCSc, FAOA, 9C University Health Center Detroit Receiving Hospital, 4201 St. Antoine, Detroit, MI 48201, (e-mail:

R. Vaidya has received research support from Pfizer and is on the editorial board of the Journal of Orthopaedic Trauma. The remaining authors report no conflict of interest.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (

Accepted November 16, 2018

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The combination injury of pelvic ring disruption and acetabular fracture is uncommon, reported to occur in 5%–15.7% of all pelvic ring disruptions and 9% of all acetabular fractures.1–5 This injury pattern is usually caused by high-energy trauma with the mechanism of injury being equally distributed between anterior-to-posterior (AP) and lateral compression (LC) forces.1,2,5 The acetabular fracture is usually a complex, associated type, as described by Letournel.6 They are associated with the patient having a high-injury severity score (ISS) and patient mortality rates above what is reported for isolated pelvic ring disruptions.1–3 Few reports of either pelvic ring disruption or acetabular fracture have included the combination injury scenarios within their studies5 and even less have reported outcomes after the treatment of these injuries.3 However, there is some controversy in the literature over what actually constitutes a combination injury of the pelvis and acetabulum. Many pelvic fractures have bilateral high pubic ramus injuries, which may involve the anterior acetabular articular surface, but are minimally displaced or have little bearing on acetabular function.5 Some acetabular fractures involve the sacroiliac (SI) joint as part of the extension of their injuries.5 In both of these situations, the lesser injury has little bearing on outcome.5

Because of the paucity of literature, management protocols for the surgical treatment of combined pelvic ring and acetabular injuries have not been studied. A single review article on this topic recommended an individualized protocol for the treatment of these injuries,5 and one series recommended reduction and fixation of the pelvic ring injury followed by acetabular fracture reduction and fixation.3 Therefore, it was our feeling that the existing treatment recommendations were vague, and the protocols were limited, without any identified determinants of patient outcomes.

The purposes of this article were to compare our combined pelvic ring and acetabular fracture patients' rate of mortality and ISS to those of patients with isolated injuries at our center and to those with combined injuries as reported in the literature, describe our treatment algorithm using the Anterior Subcutaneous Pelvic Fixator (INFIX)7 for these combination injuries, and report our patients' radiographic and functional outcomes.

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After obtaining IRB approval, we conducted a retrospective review of our database of patients who had sustained either pelvic ring trauma or acetabular fracture trauma at our institution (a Level 1 US Trauma Center).

Between January 2002 and December 2015, a total of 1697 patients treated at our facility were identified as having a pelvic or acetabular injury. Of these, 174 (10.3%) had combined injuries. Thirty-nine patients, including 2 with a bilateral injury, were operated for both injuries and followed a combined injury treatment protocol. The metrics we chose for patient evaluation included injury description, ISS, radiological result, mortality, and functional outcomes. These metrics allowed us to compare our data with previously reported findings1–4 and with isolated pelvic ring disruption and acetabular fracture patients at our own institution. All patients had X-ray and CT scans, as well as a fluoroscopic examination under anesthesia, that allowed classification of the pelvic ring and acetabular injury. Patients were classified by the AO/OTA8 and Young and Burgess9 pelvic ring classification schemes and the AO/OTA classification system for the acetabular fracture8 (which is based on the Letournel6 classification). Classification of the injuries was performed by 2 fellowship-trained attending orthopedic traumatologists. In the case of disagreements, a consensus was reached after a discussion.

In the 39 surgically treated combined injury patients, the quality of the acetabular fracture reduction was evaluated using the criteria described by Matta.10 For the quality of the reduction of LC and AP compression pelvic injuries, the Keshishyan Index (KI) was used.11,12 It is the most reproducible of radiographic pelvic measurements,12 but its values are hard to interpret. We felt that approximately 10% asymmetry or a KI value ≤0.05 was excellent, 0.05–0.1 was good, and ≥0.1 was fair to poor. Functional outcome was assessed using the Majeed13 pelvic outcome score. Functional outcome was recorded at the most recent physician follow-up patient visit, through a telephone interview or from previously collected patient visit chart data. Using the Majeed13 criteria, the patients were ranked as excellent, good, fair, or poor.

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Treatment Protocol

Upon presentation to the emergency department, patients were evaluated and treated per the Advanced Trauma Life Support guidelines.14 In patients who were hemodynamically stable or were stabilized by our trauma team and were ready for definitive pelvic stabilization, we used the following fixation strategy.

The protocol for definitive pelvic ring and acetabular fracture fixation was dependent on the fracture type. For transverse, T type, and acetabular wall fractures (62A1, 62A2, 62A3.1, 62B1, 62B2, and 62B3.1 fractures that exit below the AIIS or low fractures and allow for a supra-acetabular INFIX screw) associated with a pelvic ring injury, we first reduced and fixed the pelvic ring (Fig. 1). For anterior–posterior compression type 2 (APC2, 61B2.3, and 61B3.3) fractures, we used the INFIX in compression to reduce the pelvic injury and then fixed the posterior injury with sacroiliac screws (SI). For LC type 1 or 2 (61B2.1, 61B2.2, and 61B3.2) injuries, we used the INFIX in distraction to reduce the deformity and then stabilized the posterior injury with a fully threaded SI screws or an LC2 screw. For LC3 (61B3.1) injuries, we used a sequential reduction protocol previously described.15 For APC 3 and vertical shear injuries (61C), we reduced the posterior injury first either closed or open and fixed it with a plate or SI screws, then fixed the anterior injury (Rami or symphysis) with an INFIX (Fig. 2, see Figure 2, Supplemental Digital Content 1, After that, we considered options for the acetabular fracture treatment.





For both column, acetabular and high anterior column acetabular fractures (62A3.2, 62A3.3, 62B3.2, 62B3.3, and 62C), we reduced and fixed all pelvic ring injuries and high acetabular fractures (which exited above the AIIS) sequentially from posterior to anterior. The anterior fixation was with an INFIX for rami or symphysial injuries. Then, low fracture lesions were subsequently addressed (Fig. 3, see Figure 3, Supplemental Digital Content 2, similar to that described by Cai et al.3



All patients had heterotopic ossification (HO) prophylaxis with single dose radiation. Patients were progressed to full weightbearing status at 12 weeks postoperatively. The INFIX was removed at 12–20 weeks. We coordinated its removal with procedures for other injuries if possible.

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The mortality rate for pelvic fracture patients at our institution was 8.5% (103/1193); for acetabular fracture patients, it was 4% (20/504); and for combined injury patients, it was 5.7% (10/174 combined patients were included in both acetabular and pelvic fracture data). The average ISS was reported as 15.5 for pelvic fractures, 12.03 for acetabular injuries, and 12.5 for all combined injuries. For the 39 operated patients in this study, average ISS was 21.7. The mortality rate and ISS for our combined injury patients are similar to those reported in the literature (see Table 1, Supplemental Digital Content 3,

Of the 174 combined injuries, those excluded from study were injuries that required the pelvic ring or acetabulum fracture reduced and fixed but not both, were lost to follow-up, or were not treated according to protocol (before 2009). Therefore, 39 patients with 41 acetabular injuries (2 bilateral) were included for study. Three of the pelvic ring injuries were open (see Table 2, Supplemental Digital Content 4 Of these 39 patients, 27 were male and 13 were female with an average age 37.5 years (range 16–79 years). Five patients had posterior hip dislocations, which required relocation. Initial femoral traction was used preoperatively to maintain the femoral head reduced in the acetabulum for a number of the patients. AO/OTA and Young and Burgess pelvic ring and acetabular fracture classifications are listed in Supplemental Digital Content 4 (see Table 2,

Twenty-three patients had initial temporizing fixation followed by definitive fixation, and 16 patients had complete fixation at one setting. Temporizing measures included external anterior pelvic fixation (23 pts) ± antishock SI screws (5 pts)16 and traction for the acetabular injury either shanz pins in the femur connected to the external pelvic fixation or with a femoral traction pin. The 39 patients had on average 2.15 surgeries for pelvic and acetabular fixation during their initial hospitalization range 1–3. One patient had 9 surgeries due to infection. The average follow-up was 22 months, ranging from 6 to 96 months. Reductions of the acetabulum were anatomic in 25 (61%), imperfect in 12 (29%), and poor in 4 (10%) by the Matta criteria. The pelvic reductions measured by the KI are shown in Supplemental Digital Content 4 (see Table 2, There were 39 excellent and 2 good reductions with regard to pelvic symmetry. The 3 vertical shear injuries were all reduced to less than 1-cm superior displacement. All the fractures healed and were progressed to full weightbearing by 12 weeks postoperatively, as per protocol.

Majeed outcome scores were included for 36 patients with follow-up greater than 6 months, being excellent in 13, good in 15, fair in 3, and poor in 5. Three of the 5 patients with poor outcomes had a sciatic nerve palsy from their injury, 2 had severe HO (1 patient with both a sciatic nerve palsy and HO) related to pelvic ring and femoral shaft fractures, and 1 patient had chronic low-back pain, an occipital condyle injury and was not walking despite healing of her pelvic/acetabular injury with anatomic acetabular reduction even a year after the injury. We were unable to correlate excellent outcomes with excellent reductions because some patients with excellent reductions had a poor outcome and our numbers were limited. There were 3 patients who went on to THA (ages 35, 37, 47) and another that was scheduled at the time of latest follow-up and was doing poorly with their original fixation.

Major complications include 3 patients with deep infection (one that required 9 surgeries to stabilize the infection and one secondary to an extensive Morel-Lavallee lesion), 4 patients with significant HO of which 2 had surgical excision (Fig. 4), and 3 patients with persistent sciatic nerve palsy (1 iatrogenic).



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Combination injuries of the pelvis and acetabulum make up between 5% and 14% of cases that present with pelvic ring or acetabular injuries in reported series5 and in our series 10%. These injuries may be undisplaced or have a major pelvic or acetabular component with a minor component of the other injury that does not require much attention.5 They need to be evaluated according to the ATLS protocol14 to treat initial hemodynamic instability, placement of pelvic binders/sheets, and identify concomitant injuries, open fractures, and neurological deficits. Displaced combination injuries need to be treated in a coordinated fashion at a hospital with multidisciplinary capability. The use of temporary external pelvic stabilization may not be adequate when a high anterior column or a both column acetabular fracture is present. The use of a pelvic sheet with femoral traction in one or both legs is simple and may accomplish what is required until a definitive plan is organized.

Combination pelvic/acetabular injuries have a higher ISS than isolated acetabular injures and similar to pelvic injuries at our institution. Although the 174 patients only had an ISS score of 12.5, the 39 operated patients in our report had an ISS of 21.7 ± 11.6, which was higher than the collective group of pelvic, acetabular, or combined injuries in our database and similar to operated pelvic injuries that we have previously reported 22.75 ± 11.2 (median 21, range 5–57)13 and similar to reported by Osgood et al.1

Mortality rates for combination injuries (174) were reported as 5.7%, which is lower than that reported for pelvic fractures 8.5% at our institution (not significant). This is something that has been reported previously.5 At our institution, early deaths are caused by hemorrhage in the first 24 hours followed by head injury and multisystem organ failure after 48 hours.17

Our treatment protocol for these injuries considered if the acetabular fracture is a component of the pelvic ring injury as in an associated both column acetabular fracture or with an anterior column injury exiting above the AIIS (62A3.2, 62A3.3, 62B3.2, 62B3.3, and 62C). For these injuries, we fixed the pelvic ring posteriorly and then worked back to front considering each iliac wing separately finally connecting the anterior ring with an INFIX device. The remaining low acetabular injury is treated subsequently. In acetabular fractures that were transverse, T type, or wall fractures (62A1, 62A2, 62A3.1, 62B1, 62B2, and 62B3.1), we fixed the pelvis first and dealt with the acetabular fracture after. In these injuries, reducing the pelvis first often helped with acetabular fracture reduction and in some cases allowed for percutaneous fixation of the acetabulum or using only a subsequent Kocher-langenbeck approach. The INFIX device was helpful in holding the reduction in these cases just as an external fixator would, but we could leave the INFIX in and mix it with internal fixation in these cases (Fig. 3). Also in the past, using rigid fixation in the front of the pelvis (ie, a plate) before fixing a posterior column fracture often lead to trouble with reduction, this is not affected with INFIX because the front remains mobile (Fig. 4). We have no comparison with any other protocol in treating these injuries to say that our approach is better or even as good as another protocol, and we found that this approach served its purpose for all the injuries that we have cared for. Cai et al3 recommended a posterior to anterior fixation approach as well.

We had a fair amount of reductions we deemed anatomic from the Matta criteria on Anterior–Posterior and Judet views in the early post-op period. Lefaivre et al felt that this criteria was difficult to reproduce or may have poor interobserver reliability.18 Unfortunately, there is no validated criteria of acetabular reduction, and the judgment of perfect or offset on the 3 acetabular views is likely as good a criteria as any, and this is the most used criteria in acetabular surgery articles. Determining pelvic reduction is another issue. The KI that assesses pelvic asymmetry is a good measure for lateral compression injuries as it can tell asymmetry, but for APC injuries, it is not as reliable as symmetrical displacement returns good scores. We also added an excellent, good, and fair–poor scale for this, which is loosely based on <10% excellent, 10%–20% good, and >20% fair or poor. For vertical shear injuries, vertical displacement was assessed on the AP or outlet view to gauge displacement as well as the KI and was assessed as decently reduced in all cases.

Pelvic fractures tend to heal and so do acetabular injuries, and we did not find any nonunions in this series.

Outcomes scores showed 28/36 (78%) of the patients with good (15) or excellent (13) outcome and 22% with a fair (3) or (5) poor outcome. A fair or poor outcome was associated with severe HO in 1 patient, an imperfect reduction and severe HO in 1, imperfect or poor acetabular reduction and a persistent sciatic nerve palsy in 3, a poor acetabular reduction in 2, and in 1 patient with an anatomic acetabular reduction but chronic lumbar back pain and inability to mobilize independently. Hip replacement has good outcomes and is a good solution when there is a poor outcome with an acetabular fracture caused by malreduction. This will not solve a sciatic nerve palsy or HO. Unfortunately, patients who went on to total hip replacement were young (35, 37, and 47 years old).

Complications included 3 deep infections. They were dealt with a return to the operating room obtaining deep cultures, retention of hardware, debridement and irrigation with closure of a suction drain, or a wound vac. One patient had an extensive hospital stay due to 9 surgeries for this issue, which included antibiotic beads and delayed primary closure. Despite HO prophylaxis with a single dose of radiation, 4 patients developed significant HO to the point that it needed to be excised as the hip had ankylosed. Three patients did well, and 1 patient reankylosed his hip and walks with essentially a hip fusion but little pain (He also had a head injury) Figure 3.

The limitations of this article include the fact that it is a small case series of a complex problem, which is not that prevalent. So, many questions about treatment cannot be definitively answered except that we used this protocol, and it seemed to work for us. As more articles are published about combination injuries, a consensus can eventually be formed.

We feel from our limited work on this topic that these injuries are associated with multiple other injuries (high ISS), and their mortality rates are similar to pelvic injuries. These injuries tend to heal, and we did a good job of reducing the pelvic component of the injury. Functional outcomes of the injury at our institution depended on how well we reduced the acetabulum and if we avoided complications such as infection or severe HO. A persistent sciatic nerve palsy also resulted in a poor outcome in 3 patients.

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pelvic fracture; acetabular fracture; combined injury; INFIX; mortality; injury severity score; outcome score

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