Eur J Trauma Emerg Surg (2012) 38:185–190 DOI 10.1007/s00068-011-0147-9
ORIGINAL ARTICLE
Do stable multiply injured patients with bilateral femur fractures have higher complication rates? An investigation by the EPOFF study group Roman Pfeifer · Dieter Rixen · Elisabeth Ellingsen Husebye · Dustin Pardini · Michael Müller · Clemens Dumont · Hans Georg Oestern · Peter Giannoudis · Hans-Christoph Pape · The EPOFF study group
Received: 21 February 2011 / Accepted: 26 July 2011 / Published online: 17 August 2011 © Springer-Verlag 2011
Abstract Background Polytrauma patients with bilateral femur shaft fractures are known to have a higher rate of complications when compared with those who have sustained unilateral fractures. The current study tests the hypothesis that the high incidence of posttraumatic complications in patients who do not have a severe head or chest injury is caused by accompanying injuries rather than by the additional femur fracture. R. Pfeifer · H.-C. Pape (&) Department of Orthopaedic Surgery, University of Aachen Medical Center, 30 Pauwels Street, 52074 Aachen, Germany e-mail:
[email protected] R. Pfeifer (&) Department of Trauma Surgery, University of Aachen Medical Center, Aachen, Germany e-mail:
[email protected] D. Rixen Department of Orthopaedics and Trauma Surgery, University of Witten Herdecke and Cologne, Witten, Germany E. E. Husebye Orthopaedic Centre, Ullevaal University Hospital, Oslo, Norway D. Pardini Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA M. Mu¨ller · C. Dumont Department Trauma Surgery, Plastic and Reconstructive Surgery, University of Go¨ttingen, Go¨ttingen, Germany H. G. Oestern Department of Trauma, Celle General Hospital, Celle, Germany P. Giannoudis Department of Trauma and Orthopaedics, University of Leeds, Leeds, UK
Methods Inclusion criteria New Injury Severity Score [ 16 points; AIS score value of the chest ≤3 points and no severe head injury. Two study groups: a unilateral group (USF group) (n = 146) and a bilateral femur shaft fracture group (BSF group) (n = 19). Endpoints monitored were length of stay in the intensive care unit, duration on a ventilator, and several postsurgical complications (e.g., SEPSIS, acute lung injury). Statistics Fisher’s exact test for binary variables, and independent t-tests and regression analyses for continuous indicators of injury severity and clinical outcomes. Results Patients with bilateral femur fractures had a significantly higher incidence of hemothorax. Moreover, they received blood transfusions more often upon admission, and exhibited a longer ICU stay (p = 0.008). However, this patient group did not exhibit a significantly higher incidence of postsurgical complications (p = 0.1) than those with unilateral fractures. After adjusting for injury severity, no difference in the length of the ICU stay was observed. Bilateral fracture patients who were in an uncertain condition preoperatively had a longer length of stay in the ICU postoperatively (p = 0.002). Conclusions In the absence of major head or chest injuries, patients with multiple injuries and bilateral femur shaft fractures have a similar complication rate to polytrauma patients with unilateral fractures. Moreover, an uncertain condition preoperatively was associated with an increased stay in the intensive care unit. The results support the idea that associated injuries rather than the additional femur fracture are responsible for complications during the clinical stay. Keywords Femur fracture · Complications · Polytrauma · Risk factors
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Introduction Patients with bilateral femur shaft fractures are known to have a higher rate of complications when compared with those who have unilateral fractures [1]. This fact can be explained in different ways: some authors favor the idea that the additional fracture and its associated local soft tissue trauma could be responsible. Others stress the fact that bilateral femur fractures are associated with numerous additional injuries that may be responsible for their high incidence of complications [2–5]. However, none of these studies [1–5] have focused on patients that have sustained multiple injuries. We therefore addressed the question of whether the additional injuries or the bilaterality of the femur fracture account for complications. The current report tests the hypothesis that the increased incidence of posttraumatic complications in polytrauma patients with bilateral femur shaft fractures is caused by additional injuries rather than the additional femur fracture.
Patients and methods Definitions Fracture classification was performed according to the classification system described by the Orthopaedic Trauma Organization (OTA) of North America [6]. Open fractures were classified according to the Gustilo score [7]. The severity of injury was graded on the basis of the New Injury Severity Score (NISS) [8]. To facilitate comparison with other studies, the degree of overall injury severity was also categorized by the Injury Severity Score, calculated on the basis of AIS (ISS) [9]. The Revised Trauma Score (RTS) was calculated on the basis of the data obtained upon the arrival of the patient [10]. Severe head injury was defined as morphological evidence of cranial injury based on the initial computed tomography head scan, and if a craniotomy or medication to lower the intracranial pressure was required, or if the intracranial pressure exceeded 25 mmHg. The initial neurological state was evaluated according to the Glasgow Coma Scale (GCS) [11]. Acute lung injury (ALI) and acute respiratory distress syndrome (ARSD) were diagnosed according to the American–European Consensus Conference [12]. Systemic inflammatory response syndrome (SIRS) was defined according to the criteria of the Consensus Conference of American College of Chest Physicians and Critical Care Medicine (ACCP/SCCM) [13]. Pneumonia was diagnosed if the body temperature was at least 38.5°C and one of the following criteria was also
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met: infiltrate on chest X-ray in the absence of ARDS, or positive culture in bronchoalveolar lavage fluid. Multiple organ dysfunction (MOD) was diagnosed according to a scoring system when at least three organs demonstrated grade II dysfunction [14]. Borderline condition The determination of the clinical status (stable, borderline, unstable, in extremis) was made in the emergency room according to the clinical criteria described in prior studies [15]. The intensive care stay (ICU stay) denotes the time (in days) from admission to the intensive care unit (ICU) until transfer to a normal ward. Patients and inclusion criteria This cohort was summarized in another prospective study that looked at the outcome of femoral fracture fixation in patients who had no life-threatening injuries [5]. All patients included in this investigation were prospectively documented between January 1, 2000 and February 28, 2007 following approval by the local Institutional Review Board. The inclusion criteria consisted of a New Injury Severity Score (NISS) exceeding 16 points, a midshaft fracture of the femur suitable for antegrade intramedullary fixation, age between 18 and 65 years, a thoracic AIS value of less than four points, no severe head injury, and responsiveness to fluid administration. The exclusion criteria involved previous polytrauma, body weight [ 113.4 kg (250 lb), open epiphyseal plates, and multiple premorbid conditions. Parameters that excluded patients were: systolic blood pressure \ 90 mmHg despite fluid therapy, requirement for vasopressors, anuria, core body temperature \32°C, and a platelet count \ 80.000/μl blood (measured on hospital admission). Group distribution and endpoints Patients were allocated into two groups according to the presence of a bilateral or unilateral femur shaft fracture: The USF group consisted of polytrauma patients who had a unilateral shaft fracture of the femur The BSF group consisted of polytrauma patients who had a bilateral femur shaft fracture Endpoints of the study included number of hours in the ICU, number of hours on a ventilator, and the incidence of any systemic postsurgical complications (i.e., SIRS, sepsis, pneumonia, acute lung injuries, acute respiratory distress, multiple organ failure). All postsurgical complications were combined into a single binary variable (i.e., 52.9% = no complications, 47.1% = one or more
Do multiply injured patients with bilateral femur fractures have higher complication rates?
complications) because of the relatively small number of individuals experiencing several of the individual complications. The prevalence rates were as follows: SIRS 36%, acute lung injury 24%, pneumonia 21%, sepsis 13%, acute respiratory distress 9%, multiple organ dysfunction 5%.
General management Fixation of fractures Patients were randomly treated by either primary (24 h) intramedullary femoral nailing or by initial external fixation followed by secondary intramedullary nailing. Intramedullary instrumentation was performed in a standardized fashion for patients treated with an antegrade nail, using a piriformis fossa starting point. Retrograde nailing was performed in patients with obesity, or when adjacent open soft-tissue injuries required surgical access to the knee. In bilateral fractures, a supine position was used, and retrograde nailing was performed.
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examine treatment group differences for continuous variables that approximated a Gaussian distribution. Nonnormally distributed variables were transformed before testing. Fisher’s exact test was employed for binary indicators of injury severity. Moreover, additional analyses were then conducted to document whether individuals who suffered bilateral femoral fractures exhibited a worse postoperative course and more clinical complications following surgery than those with unilateral fractures. Linear regression analyses were used to predict medical outcomes using bilateral femoral fractures after controlling for co-occurring indicators of initial injury severity. All postsurgical complications were combined into a single binary variable (i.e., 52.9% = no complications, 47.1% = one or more complications) because of the relatively small number of individuals experiencing several of the individual complications. The presence of a bilateral femoral fracture, as well as indicators of initial injury severity that were significantly (p \ 0.05) associated with the occurrence of a bilateral femoral fracture, were entered into regressions predicting clinical course and complications following surgery.
General protocol Multiple trauma patients are regularly submitted to intubation and mechanical ventilation. For the patients included in the present study, lost volume was replaced with crystalloid or colloid solutions; hypertonic solutions were not used. Patients underwent repeated arterial blood gas measurements and measurements of central venous pressures through the insertion of a central venous catheter. Hemothoraces and pneumothoraces were typically treated with chest tubes inserted in the emergency room. Ventilator settings of patients with lung contusions usually showed a positive end expiratory pressure of 8–12 mm H2O and inverse ratio ventilation. The monitoring of intracranial pressures was performed on the basis of recommendations by the consulting neurosurgeon. Throughout surgery, continuous monitoring of the blood pressure, electrocardiogram, and rectal temperature was performed. Blood gases were drawn as needed and as deemed necessary by the attending anesthesiologist. Open fractures were routinely washed out in the operating room and stabilized either definitively or with an external fixator.
Statistics First, analyses were conducted to examine the relation between the occurrence of unilateral versus bilateral femoral fractures, as well as variables indexing patient demographic characteristics and other indicators of initial injury severity. Independent sample t tests were used to
Results One hundred sixty-five trauma patients met the inclusion criteria; 146 of these had a unilateral fracture and 19 patients had bilateral fracture of the femur. There were no significant differences in indicators of injury severity. The majority (57.5 vs. 52.6%) of the patients in both groups underwent intramedullary fixation of the femur. Results from the analyses examining the relation between bilateral femoral fractures and variables indexing patient demographic characteristics and other indicators of initial injury severity are illustrated in Table 1. Patients who suffered a bilateral femoral fracture were significantly more likely to have hemothorax and receive a blood transfusion upon admission to the hospital in comparison to patients who suffered a unilateral femoral fracture. Bilateral fracture patients were also more likely to be in borderline condition upon admission to the hospital as compared to unilateral patients. Bivariate analyses also indicated that patients with bilateral femoral fractures exhibited a longer intensive care stay but were not more likely to experience postsurgical complications than those with a unilateral facture (see Table 2). Table 3 provides data on whether bilateral femoral fracture status continued to predict time spent in the ICU after controlling for co-occurring indicators of initial injury severity (i.e., borderline condition, blood transfusion on admission, hemothorax). Patients in borderline condition spend significantly more time in the ICU than those in stable
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Table 1 Demographic and injury severity characteristics for patients with unilateral and bilateral femoral fractures
† ╬
Independent samples t test
Unilateral fracture, N = 146 M ± SD
Bilateral fracture, N = 19 M ± SD
p value
Mean age (years)
32.5 ± 11.6
33.1 ± 12.1
0.843†
Revised Trauma Score
0.87 ± 0.4
0.93 ± 0.5
0.605†
Injury Severity Score
25.7 ± 9.9
26.3 ± 7.9
0.793†
New Injury Severity Score
28.8 ± 9.9
30.1 ± 8.1
0.595†
AIS head
1.4 ± 1.5
1.2 ± 1.4
0.550†
AIS face
0.4 ± 0.9
0.4 ± 0.8
0.852†
AIS thorax AIS abdomen
1.9 ± 1.6 1.1 ± 1.5
2.2 ± 1.8 0.8 ± 1.1
0.587† 0.468†
AIS extremities
3.2 ± 0.7
3.5 ± 0.6
0.082†
AIS external
0.3 ± 0.7
0.4 + 0.6
0.625†
Gender (% male)
78.8%
89.5%
0.370╬
Femoral nailing Tx
57.5%
52.6%
0.685╬
Open femoral fracture
24.0%
36.8%
0.264╬
Borderline condition
24.0%
47.4%
0.030╬
Blood transfusion \ 24 h
26.9%
52.9%
0.027╬
Rib fractures
70.0%
81.3%
0.557╬
Hemothorax
10.3%
31.3%
0.034╬
Pneumothorax
16.7%
31.3%
0.174╬
Lung contusion
55.5%
68.8%
0.313╬
Fisher’s exact test
Table 2 Femoral fracture group differences in clinical course and postsurgical complications Unilateral fracture, N = 146 M ± SD Hours in intensive care Hours on ventilation Postsurgical complications
Bilateral fracture, N = 19 M ± SD
p value
12.2 + 8.6
18.2 + 8.2
0.008‡
9.8 + 7.6
13.3 + 8.7
‡
0.074
Hemothorax
66.7%
0.103╬
46.2%
Predictors
╬
Hours in the intensive care unit B
Hours in ICU and on ventilation were square-root transformed due to significant skewness. Postsurgical complications included any of the following: acute lung injury, acute respiratory distress, systemic inflammatory response, sepsis, multiple organ failure ‡
Table 3 Linear regression analyses predicting length of ICU stay based on bilateral femoral fracture status after controlling for cooccurring indicators of initial injury severity
Independent sample t test
Borderline condition
SE
β
p
6.039
1.904
0.299
0.002
−0.673
2.277
−0.027
0.768
Blood transfusion
2.143
1.667
0.118
0.201
Bilateral femoral fracture
4.774
2.515
0.174
0.060
R2
0.18
Hours in the ICU were square-root transformed Unstandardized coefficients B and SE (standard error) Standardized coefficient β (beta)
Fisher’s exact test
condition, and bilateral fracture was no longer a significant predictor of ICU stay. These findings indicate that the relation between bilateral femoral fracture status and medical outcome can be accounted for by co-occurring indicators of initial injury severity upon admission to the hospital.
Discussion Although numerous authors have raised concerns regarding the presence of bilateral femur fractures, many published
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studies constitute case reports or retrospective collections of smaller patient samples with undefined patient populations [3, 4, 16, 17]. In the present study, we included femur fracture patients who are polytraumatized but have no lifethreatening injuries. We feel that this approach provides new information, as it focuses on the subgroup of patients in which the management of fracture fixation has been debated in the past. Our main results were as follows. (1) In patients who have no severe associated injuries of the head and the chest, multivariate analysis to control for injury severity showed no difference between unilateral and bilateral
Do multiply injured patients with bilateral femur fractures have higher complication rates?
factor patients in ICU complications, such as acute lung injury, acute respiratory distress, systemic inflammatory response, sepsis, and multiple organ failure. (2) A prolonged stay in the ICU was found for patients in borderline condition. Ventilation time was similar to patients with a unilateral fracture. Our study has limitations, such as a lack of control for the severity of soft-tissue injuries associated with femoral shaft fractures, a relatively small sample of the bilateral fracture patients. This causes a lack of power to detect differences. Moreover, we are unable to provide a randomized study protocol. Finally, the selection of patients allows for only a limited conclusion about the subpopulation of polytrauma patients. On the other hand, the precise inclusion criteria enhance the clinical relevance of the findings observed in this population: the Injury Severity and the Revised Trauma Score results did not differ from the group that presented with a unilateral femur fracture. Also, the ranges in ventilation times and intensive care stays were similar in both groups. Moreover, the distribution of the pattern of the femur fracture was comparable. We therefore feel that the information gathered in this report is relevant. We also assume that this selection of patients is adequate to differentiate whether adverse events during the hospital course are caused by the additional fracture or not. Two studies of large patient samples have been published so far. Copeland found that both the number and severity of associated injuries are higher in patients with bilateral femur fractures [2]. Nork et al. reviewed 743 patients with femoral shaft fractures, 54 of whom had bilateral injuries [1]. Their raw data demonstrate a longer stay in the intensive care unit, a longer hospital stay, a higher Injury Severity Score, and a higher mortality rate in patients with bilateral fractures. After controlling for differences in injury severity by regression analysis, they confirm a longer stay in the ICU and in the hospital and a 3.8-fold increase in the risk of mortality for patients with bilateral fractures [1]. The results of the present investigation support the previous studies [1, 3] in that additional injuries in patients with bilateral femur fractures play an important role in the clinical course. Regarding our first finding, one might have expected a higher incidence of complications in bilaterally injured patients. The absence of such increased complication rate may be a useful guide to clinical management in this particular population. Once additional severe injuries are ruled out, it appears justified to treat patients with bilateral fractures similarly to those with unilateral fractures. This may include the indication for definitive fracture treatment in these patients. Patient selection appears to play a major role. While the studies cited above [1, 2] list all patients that were cleared for surgery and
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included patients with isolated fractures, the current study summarizes patients with multiple injuries only. Moreover, patients with severe head and chest injuries were not included. In our data, which were not corrected for injury severity, the amount of blood transfusion appeared to play a role. Replacement of blood has been described in many studies as an independent risk factor for the development of complications [18, 19] and mortality [19, 20]. Likewise, the presence of a hemothorax has been described as an independent risk factor for adverse outcome. These findings may explain why both hemorrhage and hemothorax were risk factors when no stratification for injury severity was performed [21–25]. These factors did not play a role once stratification for injury severity was performed. The degree of soft-tissue injury may play a role in the development of systemic complications. In many studies, this effect appears to have been underestimated, although some authors have stressed its importance regarding infectious and systemic complications [26–28]. Others have documented the presence of local inflammatory mediators in major extremity fractures, and suggested that they might be relevant for systemic sequelae [29]. Experimental studies revealed systemic inflammation to be the highest in fractures with associated soft-tissue injuries and higher after soft-tissue injury alone when compared with fracture alone. In the present investigation, the values of soft-tissue injuries based on the Abbreviated Injury Scale were comparable in both groups. To account for other concerns addressed by previous authors who discussed the value of the Injury Severity Score [1, 2], the New Injury Severity Score was used, a more precise indicator of multiple extremity injuries [8, 30]. In summary, the results of this investigation support the hypothesis that the high incidence of posttraumatic complications in polytrauma patients with bilateral femur shaft fractures is caused by accompanying injuries rather than by the additional femur fracture itself. The bilateral femur fracture failed to be an independent predictor for the length of stay. It was also found that independent risk factors (e.g., borderline condition) are present that may affect the clinical course. Moreover, our results support the idea that the general management in this population can be performed in a similar fashion whether or not bilaterality of a femur fracture is present, as long as additional risk factors are absent. Acknowledgments Project P3 02.
This study was funded by the AO Foundation,
Conflict of interet The authors declare that there are no further conflicts of interest.
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