Pelvic Ring Disruptions: Mechanism, Fracture Pattern, Morbidity And Mortality. An Analysis Of 325 Patients
"aside from these grossly unstable fracture types, we found little evidence that fracture patterns reliably predicted associated injuries, resuscitation requirements, or probability of death."
Adam J. Starr MD, Damian R. Griffin MA FRCS (Orth), Charles M. Reinert MD, Joan Walker RN, Shelley N. Whitlock CCRA, Ashutosh V. Rao MD*, Drake S. Borer MD, Alan L. Jones MD
Departments of Orthopaedic Surgery and Radiology(*). University of Texas Southwestern Medical Center, Dallas, Texas
INTRODUCTION
Our purpose in this study is: (1) to report the results of our analysis of patient variables that are available to the clinician early in the patient's clinical course, to determine if any of these variables are predictive of mortality, transfusion requirements, later complications, or injuries associated with the pelvic ring disruption; and (2) to report the early morbidity and mortality encountered in the management of patients with pelvic ring disruptions.
MATERIALS AND METHODS
All patients who sustained closed disruptions of the pelvic ring between November 1, 1997 and November 30, 1999 were included. All data was entered into a prospectively collected database. This data was retrospectively analyzed for the purposes of this study. Age, mechanism of injury, systolic blood pressure, revised trauma score (RTS) and base deficit on arrival were recorded. Shock was defined as systolic blood pressure < 90mm Hg, and patients in shock on arrival were noted. The pelvic fractures were classified according to the Young Burgess system, after examination of admission radiographs. Isolated fractures of the iliac wing were excluded, as were fractures due to gunshot wounds. Abbreviated injury scores and injury severity scores (ISS) were calculated. Transfusion requirements in the first 24 hours were recorded. Complications occurring during the hospital stay were noted. Patient deaths were recorded. Management of the pelvic fractures and associated injuries was carried out by a team of orthopaedic and trauma surgeons. External fixators were not used for fracture stabilization. Temporary stabilization of APC type fractures was obtained through use of a bedsheet wrapped around the patient's greater trochanters, or through the use of a pelvic binder. Pelvic arteriography and embolization of bleeding vessels were used when deemed appropriate by the trauma team.
RESULTS
Three hundred twenty five patients met the inclusion criteria. The average age was 37. Mechanisms of injury were as follows: MVC 199; MPC 42; fall 42; MCC 12; crush 9; machine related injury 5; sport 4; 3 ATV crashes; 4 bicycle crashes; 3 horseback riding injuries; 2 were assaulted. The fractures were classified as follows: 209 lateral compression type 1 (LC 1); 34 lateral compression type 2 (LC 2); 23 lateral compression type 3 (LC 3); 1 anteroposterior compression type 1 (APC 1); 21 anteroposterior compression type 2 (APC 2); 13 anteroposterior compression type 3 (APC 3); 20 vertical shear (VS); 4 combined mechanical (CM). There was no clear association between mechanism and fracture pattern, except for a higher rate of APC type injuries after MCC (p<0.05). Twenty eight were in shock (systolic blood pressure < 90mm Hg) on arrival. There was an association between fracture pattern and the presence of shock on arrival: LC 1 and LC 2 fractures showed lower than expected rates of shock on arrival, while APC 3 fractures showed a rate of shock higher than expected (Fisher Exact test p=0.015). Thirty two underwent pelvic arteriography. Twenty one of these had embolization of a bleeding vessel. Only two of the thirty two patients who underwent arteriography were in shock on arrival. There was no link between any particular fracture pattern and the need for arteriography. Patients who underwent arteriography received an average of 12 units of PRBC's during the first 24 hours, compared to an average of 1.3 units for the first 24 hours for the 293 patients who did not undergo arteriography. This difference was statistically significant (p<0.001). Ten of the 32 who underwent arteriography died, compared to 28 deaths in the 293 who did not undergo arteriography. This difference was statistically significant (p<0.001). Links between fracture pattern and associated injuries were examined statistically. LC 1 fractures were found to have fewer associated injuries and a lower ISS than the other fracture patterns (p=0.001). APC 2, APC 3, and LC 2 fractures were often associated with abdominal and extremity injuries. Head injuries tended to coincide with the APC 2 pattern. LC 3 and VS fractures occurred with more severe abdominal, chest and head injuries and were associated with a higher ISS than other patterns (p=0.007 for LC 3, p=0.043 for VS). Although patients with APC 3 fractures had high ISS (mean 26.7), analysis of the small number of patients with APC 3 fractures did not reveal a significant association between APC 3 and increased ISS (p=0.166). Patients in shock on arrival had high ISS (average 36.8), compared to an average ISS of 16.7 for those patients not in shock on arrival. This difference was statistically significant (p<0.001). Thirty six patients died, for an overall mortality rate of 11%. Increasing severity of pelvic fracture instability was associated with an increased mortality rate. Fracture pattern was significantly associated with death (p=0.003). LC 1 fractures were associated with lower risk (8%, p=0.01) than other patterns, while LC 3 fractures showed a higher risk than other fracture types (35%, p=0.002). High death rates for APC 3 (29%) and VS (15%) fractures were not statistically significant. With LC fractures, there was a marked trend in increased mortality from LC 1 to LC 2 to LC 3 (p=0.008), but this study did not demonstrate a significant trend within the APC fractures. Mortality rates for LC 2, APC 1, and CMI were lower than the average mortality for the entire study group (5.8%, 0% and 0%, respectively). Shock on arrival was strongly associated with mortality (p<0.001). Overall average transfusion requirement for the first 24 hours was 2.8 units of packed red blood cells. Shock on arrival, base deficit, and RTS all significantly correlated with transfusion requirement (p<0.001). For the LC fractures, transfusion requirement increased as the fractures increased in severity from LC 1 to 2 to 3 (p=0.013). There was no significant increase in transfusion requirement in the APC type injuries. Increased transfusion requirement was associated with death (p<0.001). Patients who died had on average 10.8 more units of blood than patients who survived (95% confidence interval 6.3 to 15.4). Pneumonia, atelectasis and decubiti were seen most frequently in patients with LC 1 fractures. Coagulopathy was seen most frequently in patients with APC 2, APC 3, LC 2 or LC 3, or VS fractures. Pancreatitis and acalculous cholecystitis were seen most commonly in patients with LC 2 or LC 3 fractures.
DISCUSSION
Our study did not correlate entirely with the findings of the investigators who described the Young Burgess classification system (1) in that we were unable to demonstrate consistent links between specific fracture classes and specific associated injuries. Increased severity of injury was seen with grossly unstable fracture patterns, especially the VS and LC 3 types. In our series, the patients with APC 3 fractures did have a high mean ISS, but we were unable to demonstrate a statistical link between the occurrence of an APC 3 fracture and increased ISS. APC 3 fractures were, however, significantly associated with hypotension on arrival, confirming the severity of these injuries. Shock on arrival correlated with a high ISS. Similarly, increased transfusion requirement was seen with increased severity of pelvic ring injury in the LC fractures, but there was no significant association between other patterns and resuscitation requirements. Shock on arrival, base deficit and RTS correlated with transfusion requirement. Patients with the most unstable pelvic ring injuries experienced the highest mortality rates. This association was statistically significant for LC 3 injuries, but even in this large study the association between APC 3 and VS fracture patterns and increased mortality did not reach significance. Shock on arrival correlated strongly with mortality. Complications were not consistently linked with particular fracture patterns in most cases. The association of atelectasis and decubitus ulcers with LC 1 fractures was likely due to the excess of older patients in the LC 1 group. The association of coagulopathy with APC 2 or 3 or LC 2 or 3 fractures, and pancreatitis and acalculous cholecystitis with LC 2 or 3 injuries are difficult to explain. In conclusion, this study confirms that fractures with gross instability of the pelvic ring (LC 3, APC 3, or VS patterns) should alert the clinician to the severity of the patient's condition. These patients are subject to a higher rate of mortality, higher ISS, and greater transfusion requirement. However, aside from these grossly unstable fracture types, we found little evidence that fracture patterns reliably predicted associated injuries, resuscitation requirements, or probability of death. Of the patient variables available to the clinician early in the patient's course, shock on arrival seems the most reliable predictor of increased risk of mortality, high ISS, and greater transfusion requirement.
REFERENCES
1. Dalal SA, Burgess AR, Siegel JH, et al. Pelvic fracture in multiple trauma: Classification by Mechanism is key to pattern of organ injury, resuscitative requirements, and outcome. J Trauma 29: 981-1002, 1989.