The anterior frame external fixator has gained widespread acceptance into the management of these injuries. Originally used for definitive fixation of open-book type injuries, many centres use them as a stabilizing frame for all pelvic injuries, in the belief that this controls the fracture and reduces haemorrhage. The posterior or Ganz pelvic clamp was developed to stabilize posterior disruptions.

There is little evidence to support the use of the external fixator (over noninvasive stabilization) in the control of haemorrhage. No prospective, randomized trials have been conducted. There is sufficient level 2 evidence to conclude that some method of stabilizing the pelvis is useful initially, but no evidence to differentiate between simple sheet wraps, the anterior eternal fixator or the posterior (Ganz) clamp.

Haemorrhage after pelvic injury is from fracture surfaces, venous plexuses and major arteries, usually branches of the internal iliac artery (hypogastric artery). Depending on patient selection and injury characteristics, studies report the incidence of arterial injury requiring angiographic embolization as being up to 33.3%.

Stabilization of the pelvis will help control bleeding from bony surfaces and venous bleeding, but not arterial haemorrhage. These rapients rapidly become cold and coagulopathic. Early stabilisation of the pelvis allows clot to form while clotting mechanisms are still intact. However the external fixator will only adequately control a rotationally unstable pelvis, and may worsen a posterior injury.

The ideal method of emergent pelvic stabilization is not clear, and depends to some extent on the fracture pattern. However there are complications associated with external fixation. Application may take some time, especially with more complex pelvic injuries. The frame can interfere with subsequent laparotomy and pin site sepsis can preclude definitive open reduction & internal fixation of pelvic and anterior column acetabular fractures.

Ultimately the decision whether to apply an external fixator depends on the systems and personnel in place at an institution, the spectrum of staff available who are skilled in the application of external fixation versus interventioal radiologists and trauma surgeons.

Evidence

Level I

Waikakul S; Harnroongroj T; Vanadurongwan V
'Immediate stabilization of unstable pelvic fractures versus delayed stabilization.'
J Med Assoc Thai, 1999 Jul, 82:7, 637-42

To compare the immediate and long term outcome of immediate stabilization of the unstable pelvic fractures to delayed stabilization with simple external fixation, the study was carried out as a paralell trial with 2 year follow-up. There were 112 patients with 69 males and 43 females who had unstable pelvic fractures. They were allocated randomly into 2 groups. In group 1, 40 patients, conventional management was performed while in group 2, 72 patients, reduction and anterior stabilization of pelvic fractures with a simple external fixator were carried out immediately just after the unstable fractures were detected. Blood transfusion, post operative pain, need of reconstructive surgery of the pelvic fractures and late deformities were less in the group 2. Immediate anterior reduction and stabilization of the unstable pelvic fractures gave encouraging results.

Level IIa

Bassam, D., G. A. Cephas, et al
A protocol for the initial management of unstable pelvic fractures.
Am Surg 1998 64(9): 862-7

Design: Prospective Cohort Study
Fracture Type: Tile B,C, Young & Burgess APC2 & 3, LC2 & 3, VS
Study Population: 15
Methods: Patients with anteriorly unstable inguries underwent emergent external fixation, while primarilyu posterior injuries underwen emergent angiography.
Results: Blood product & hospital stay similar in the two groups. Complication rate higher in external fixation group, due to failure to adequately control haemorrhage.
Conclusions: APC 2&3, LC 2&3 and VS injuries who are unstable due to their pelvic injuries should undergo immediate angiography if laparotomy is not indicated.

Comments: Non-randomised, small study. However no patient undergoing emergent angiography required a second intervention to control bleeding, compared to 50% of the external fixation group, who went on to angiography. Also massive thigh/buttock/flank haematomas seen in the ex-fix group.

Level IIb

Grimm MR, Vrahas MS, Thomas KA
Pressure-volume characteristics of the intact and disrupted pelvic retroperitoneum.
J Trauma 1998 Mar; 44(3):454-9

Design: Cadaveric Model
Fracture Type: Open book
Study Population: 6
Methods: External iliac vein cannulated & ruptured. Fluid transfused into the intact retroperitoneum. Pressure measurements taken before and after external fixation, and after laparotomy.
Results: Intact pelvis - pressure 30mmHg after 5 litres. After fracture - 35 mmHg after 20 litres. External fixation increased pressure by 3mmHg at low volumes to a maxium of 11mmHg at high volumes. Laparotomy decreased retroperitoneal pressure from 35mmHg to 15mmHg.
Conclusions: low-pressure venous hemorrhage may be tamponaded by an external fixator, given that enough fluid volume is present in the pelvic retroperitoneum. External fixation may not generate sufficient pressure to stop arterial bleeding. A large volume of fluid must be lost into the pelvis before an external fixator can have much effect on retroperitoneal pressures.

Ghanayem AJ, Wilber JH, Lieberman JM, Motta AO
The effect of laparotomy and external fixator stabilization on pelvic volume in an unstable pelvic injury.
J Trauma 1995 Mar; 38(3):396-400

Design: Cadaveric Model
Fracture Type: Tile B, APC II
Study Population: 5
Methods: Pelvic volume measured by CT scanning. With/without external fixator. With/without laparotomy.
Results: Opening the abdomen increases pelvic volume by around 15% (400mls). Internal fixation reduces the volume of the pelvis (with or without laparotomy wound) by around 25% (700mls).
Conclusion: Supports reduction and temporary stabilization of unstable pelvic injuries before or concomitantly with laparotomy.

Comment: Advocates closing the pelvic volume without determining the effect this has on haemorrhage. Does not support the external fixator over other methods of pelvic fixation.

Simonian PT, Routt ML Jr, Harrington RM, Tencer AF
Anterior versus posterior provisional fixation in the unstable pelvis. A biomechanical comparison.
Clin Orthop 1995 Jan; (310):245-51

Design: Cadaveric Model
Fracture Type: Tile C
Study Population: 6
Methods: Movement at superior raums fracture and sacroiliac joint measured before and after injury, with anterior external fixator and with posterior (Ganz) clamp
Results: Motions were significantly greater than the intact specimen with both the external fixator and the posterior clamp. There was no significant difference between the Ganz clamp and the external fixator.

Moss MC; Bircher M
Volume changes within the true pelvis during disruption of the pelvic ring - where does the haemorrhage go?
Injury 1996;27 Suppl 1:S-A21

Fractures of the pelvis are not only common but are very varied in their complexity. They represent 3% of all fractures (1), they account for 1 in every 1000 surgical admissions and are the third most commonly encountered injury in motor vehicle accident fatalities (2). However, only a small percentage of all pelvic fractures are associated with major disruption of the pelvic ring (3). Life threatening haemorrhage is a frequent complication of major pelvic fractures (1, 4) and haemorrhage is the leading cause of death in these patients (5, 6). It was believed that fracture and subsequent displacement of the ring greatly increased pelvic volume. However, clinical practice seemed to indicate that this might not be true. This study aimed to assess the change in pelvic volume which occurs in severely displaced pelvic fractures. A model of the bony pelvis was designed to permit extreme displacements of the symphyseal and sacroiliac joints. The volume of a polythene balloon placed within the true pelvis was measured as an indication of true pelvic volume. Our finding was that the increase in the volume of the true pelvis which occurs in a fracture with massive diastasis is much smaller than previously assumed.

Ghanayem AJ; Stover MD; Goldstein JA; Bellon E; Wilber JH
Emergent treatment of pelvic fractures. Comparison of methods for stabilization.
Clin Orthop 1995 318:75-80

The emergent care of an unstable pelvic ring disruption in the patient who is hemodynamically unstable includes rapid application of military antishock trousers or an external fixator in an attempt to control bleeding and hemodynamically stabilize the patient. However, use of the military antishock trousers is limited in that it restricts access to the abdomen and lower extremities. The external fixator is limited at many institutions by the need to apply it in the operating room. Two experimental devices have been developed to provide emergent pelvic fracture reduction and temporary stabilization in the trauma room, while maintaining access to the abdomen and lower extremities. This study compared the efficacy of pelvic fracture reduction and stabilization in a cadaveric model using an external fixator with the efficacy of 2 experimental devices, the pelvic stabilizer and the pelvic c-clamp. Based on their ability to restore pelvic volume and reduce pubic diastasis and their application time, the 3 devices performed similarly. Complications in applying each device were noted but were of less clinical significance for the external fixator. Surgeon practice on cadavera before clinical use will help ensure safe application of either experimental device in the trauma room.

Kyle F. Dickson; Joel M. Matta, MD
Skeletal Deformity Following External Fixation of the Pelvis
American Academy of Orthopaedic Surgeons 1998 Annual Meeting - Scientific Program Paper No: 075

The clinical observation of a flexed and internally rotated hemipelvis in patients with an unstable pelvis who were treated with an anterior external fixator prompted this study. Using three-dimensional measuring techniques, the authors reviewed the radiographs of pre- and post-external fixator placement in the referred patients with an initial hemodynamic and mechanically unstable pelvis. The authors found 67% of the patients had worsening of the deformity posteriorly. The most frequent deformities of the hemipelvis were cephalad and posterior translation, internal rotation, and flexion. An equal number of abduction and adduction deformities existed. Worsening of the external fixation deformity occurred in 73% of the patients. All cases had a maximum measurement of displacement greater than 1 cm (average 3 cm; range: 1.5 cm to 5.4 cm) after placement of an external fixator.

Level III

Riemer B, Butterfield SL, Diamond DL, Young JC et al
Acute mortality associated with injuries to the pelvic ring: The role of early patient mobilization and external fixation.
J Trauma 1993 35(5): 671-677

Design: Retrospective Review
Fracture Type: Tile B,C
Study Population: 605
Methods: Protocl employing external fixation and early mobilization introduced to the unit in 1982. Three groups of patient studied. Pre-protocol, transitional and post-protocol introduction.
Results: Mortality rates fell from 26% to 6%. Mortality for patients hypotensive on admission fell from 41% to 21%. Proportion of patients undergoing external fixation rose from 3% to 31% (52% for hypotensive patients).

Comments: There is no indication about how often the application of an external fixator restored blood pressure. Also no indication as to the use of angiographic embolization over this time period.

Moreno C, Moore EE, Rosenberger A, Cleveland HC
Hemorrhage associated with major pelvic fracture: A multispecialty challenge.
J Trauma 1986 26(11): 987-994

Design: Retrospective Review
Fracture Type: All pelvic fractures
Study Population: 92
Methods: Selected patients requiring > 6 units of blood transfusion on first post-injury day.
Results: Overall mortality 26.1%. 10 deaths from haemorrhage (10.8%). PASG applied in 47patients, controlled haemorrhage in 12 (25.5%). External fixator applied in 19, controlled haemorrhage in 10 (52.6%). Angiography controlled haemorrhage in 5/7.

Comments: Retrospective study that fails to adequately describe management of injury according to fracture pattern. Management protocol does not utilise angiography after laparotomy to control retroperitoneal haematoma.

Hupel TM, McKee MD, Waddell JP, Schemitsch EH
Primary external fixation of rotationally unstable pelvic fractures in obese patients.
J Trauma 1998 Jul; 45(1):111-5

Design: Retrospective Review
Fracture Type: Tile B, APC II
Study Population: 42
Methods: Achievement or maintenance of reduction by external fixator assessed from radiographs and clinical data
Results: Overall external fixator was unable to control 6.25% of non-obese pelvic injuries and 50% of those in obese patients. With pure open book fractures, anterior external fixation did not control 12.5% of nonobese patients and 100% of obese patients
Conclusion: Higher incidence of inability to obtain or maintain pelvic stabilization using external fixation.

Comment: Overall there was a 16.7% failure rate with external fixation, rising to 46% when studying pure open-book injuries.

Gylling SF, WR, Holcroft JW, Bray TJ, Chapman MW
Immediate External Fixation of Unstable Pelvic Fractures.
Am J Surg 1985 150(12): 721-724

Design: Retrospective Review
Fracture Type: Tile B,C, APC II-III
Study Population: 66
Methods: Compares two groups, patients with mechanically unstable fractures treated with external fixation, and those with mechanically stable fractures treated with bed rest, regardless of haemodynamic instability.
Results: Overall mortality 12%. Haemodynamic parameters similar in the two groups, but mean 16 units of blood given to mechanically unstable group compared to 6 in the unstable group. Mortality in the two groups was similar.
Conclusion: 'Any patient with multiple trauma who has an unstable major pelvic fracture should undergo immediated external fixation.'

Comments: Although mortality in the two groups was similar, the results do not adequately support the conclusion. Authors themselves comment in the discussion: 'The avergae high transfusion requirement in the unstable group suggests that the external fixator did not limit haemorrhage'.

Guide to Evidence Appraisals

The definitions of the types of evidence and the grading of recommendations used originate from the US Agency for Health Care Policy and Research