Accepted Manuscript Title: Location of Civilian Ballistic Femoral Fracture Indicates Likelihood of Arterial Injury Author: Leah Gitajn Paul Perdue John Hardcastle Robert V. O’Toole PII: DOI: Reference:
S0020-1383(14)00258-7 http://dx.doi.org/doi:10.1016/j.injury.2014.05.020 JINJ 5750
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
7-10-2013 2-5-2014 18-5-2014
Please cite this article as: Gitajn L, Perdue P, Hardcastle J, O’Toole RV, Location of Civilian Ballistic Femoral Fracture Indicates Likelihood of Arterial Injury, Injury (2014), http://dx.doi.org/10.1016/j.injury.2014.05.020 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Location of Civilian Ballistic Femoral Fracture Indicates Likelihood of Arterial Injury
Leah Gitajn, BS, Paul Perdue, BS, John Hardcastle, MD, and Robert V. O’Toole, MD
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From R Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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Corresponding author:
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Robert V. O’Toole, MD
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R Adams Cowley Shock Trauma Center
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Department of Orthopaedics
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University of Maryland School of Medicine
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22 S. Greene Street, Suite T3R62
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Baltimore, MD 21201.
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Tel.: 410.328.6292; fax: 410.328.2893.
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E-mail address: [email protected]
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ABSTRACT
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Background: We evaluated whether the location of a ballistic femoral fracture helps predict the
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presence of arterial injury. We hypothesized that fractures located in the distal third of the femur
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are associated with a higher rate of arterial injury.
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Methods: We conducted a retrospective review of electronic medical records at our level I
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trauma centre and found 133 consecutive patients with femoral fractures from civilian gunshots
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from 2002 through 2007, 14 of whom sustained arterial injury. Fracture extent was measured
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with computerized viewing software and recorded with a standard technique, calculating
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proximal, distal, and central locations of the fracture as a function of overall length of the bone.
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Analyses were conducted with Student’s t, Chi-squared, and Fisher’s exact tests.
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Results: The location of any fracture line in the distal third of the femur was associated with
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increased risk of arterial injury (P < 0.05). The odds ratio for the presence of arterial injury when
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the proximal fracture line was in the distal third of the femur was 5.63 (95% confidence interval,
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1.7−18.6; P < 0.05) and when the distal fracture line was in the distal third of the femur was 6.72
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(95% confidence interval, 1.78−25.44; P < 0.05).
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Conclusions: A fracture line in the distal third of the femur after ballistic injury is six times
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more likely to be associated with arterial injury and warrants careful evaluation. Our data show
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that fracture location can help alert clinicians to possible arterial injury after ballistic femoral
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fracture.
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Introduction
Penetrating extremity trauma is commonly encountered at busy trauma centres, and diagnosing all injuries in a timely manner is critical. Of particular importance is the evaluation of
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vascular integrity after penetrating trauma. Rapid diagnosis of arterial injury is critical to prevent
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complications of prolonged limb ischemia, including compartment syndrome, arteriovenous
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fistula, ischemic contracture, and limb amputation.1,2
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Controversy exists regarding the appropriate diagnostic tools indicated in the setting of
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penetrating extremity trauma. Historically, all penetrating extremity trauma underwent surgical
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exploration. More recently, angiography has been used to diagnose vascular injury in all cases of
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extremity trauma.3−6 However, the necessity for angiography in all penetrating trauma cases has
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become controversial, and some data suggest that “hard” signs of vascular injury revealed by
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physical examination detect those vascular injuries that require immediate surgical repair
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rendering further imaging studies unnecessary. Hard signs include active hemorrhage, distal
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ischemia, and bruit or thrill over the wound.7
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Fractures that occur as a result of penetrating trauma deserve particular attention.
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Ballistic fractures are associated with a twofold higher rate of total vascular injury (both those
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that present with hard signs during physical examination and those without hard signs).8,9
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Additionally, the need for surgical repair of vascular injury is nearly doubled in cases of ballistic
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injury with fracture compared with cases of ballistic injury without fracture.8,9 Norman et al.9
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found a threefold increase in the incidence of arterial injuries that did not present with hard signs
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during physical examination (“subclinical” or “occult” injuries). Furthermore, the presence of
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fracture renders physical examination more challenging to perform and more difficult to
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interpret.10 Several possible reasons for the increased incidence of arterial injury in association 3 Page 3 of 30
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with ballistic fractures compared with other ballistic injuries include creation of a secondary
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bony missile and tethering of vascular structures to bone.11 Considering that plain radiographs are universally obtained of each patient suspected of
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having a fracture, this study was undertaken to determine whether the plain radiographs can be
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used to predict the presence of arterial injury in the setting of a femoral fracture resulting from a
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civilian gunshot. Considering that the superficial femoral artery is tethered to the femur as it
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passes through Hunter canal in the adductor hiatus, it is possible the fractures near that location
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are more likely to cause arterial injury. Therefore, we hypothesized that ballistic femoral
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fractures located in the distal third of the femur are more likely to be associated with arterial
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injury.
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Patients and methods
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Study group
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After approval from our institutional review board, we conducted a review of 2546
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patients who had sustained gunshot wounds and were admitted to our urban level I trauma centre
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from 2002 through 2007. Patients were identified with the use of a prospective trauma registry
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database.
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Each of the patients selected for the study met the inclusion criterion of having sustained
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a gunshot wound that resulted in a femoral fracture (n = 153). Eighteen patients were excluded
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because their plain radiographs did not contain the entire femur for measurement of femoral
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length, and two patients were excluded because they had sustained ballistic injuries from
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shotguns. Shotgun injuries were excluded because they are caused by a different mechanism of
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injury. A shotgun shell contains from a few to hundreds of pellets, leading to a very different
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injury pattern that is more similar to injury caused by high-velocity ballistics than injury caused
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by civilian gunshot.40 One of the patients who sustained a shotgun injury also sustained an
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arterial injury. The 133 remaining patients who sustained femoral fractures as a consequence of
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civilian gunshot wounds to the lower extremity were identified and comprised the study group.
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We reviewed all electronic medical records, including radiology reports, to determine the
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presence (n = 14, 11%) or absence (n = 119) of arterial injury in each patient. Arterial injury had
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been confirmed by angiography or computed tomographic (CT) angiography. Twelve of 14
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patients with arterial injury were treated with vascular repair. Of those with arterial injury, the
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superficial femoral artery was injured in eight (57%), the common femoral artery in one (7%),
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and the popliteal artery in five (36%). Two patients sustained arterial injuries that were not
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treated operatively because of minimal arterial wall disruption (intimal defects with intact distal
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circulation or pseudoaneurysm). Of the 20 excluded patients, two had vascular injuries.
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From our database, we retrieved demographic data on all patients in our study group,
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including patient age, sex, date and timing of injury, mechanism of injury, Revised Trauma
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Score (RTS) measured at the scene of injury and measured at admission, Injury Severity Score
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(ISS), Trauma and Injury Severity Score (TRISS), admission Glasgow Coma Scale score, blood
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pressure, heart rate, admission and discharge dates, number of days in the intensive care unit,
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scene time, injury type, method of injury, specific patterns of injury, and disposition. The data
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were used to ensure that the two study groups were similar demographically.
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No significant difference was shown between the patients with and without arterial injury
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regarding age, sex, race, mechanism of injury, diastolic blood pressure, respiratory rate,
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temperature, RTS at the scene, TRISS, admission Glasgow Coma Scale score, number of days
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spent in the intensive care unit, or scene time. However, a significant (P < 0.05) difference was
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shown between the two groups regarding systolic blood pressure, heart rate, RTS at admission,
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ISS, and days in hospital, as might be expected (Table 1).
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Radiographic Measurement
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Two of our co-authors who were blinded to the presence or absence of arterial injury
obtained measurements from the anteroposterior view postoperative radiographs of the femur.
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All fractures in this study had been treated with intramedullary nail insertion, and the nail was
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present in all images. Images were viewed with the use of IMPAX for Radiology software (Agfa
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HealthCare, Greenville, SC) on computerized workstations that are used at our institution for
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clinical viewing of radiographs on a picture archiving and communication system. The IMPAX
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Markup Caliper tool (Agfa HealthCare) was used to measure the length of the femur in
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millimeters.
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A standardized technique was used to measure each fracture (Fig. 1). One line was drawn
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perpendicular to the lesser trochanter and another across the most distal part of the femoral
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condyles. The length of the femur was recorded as the distance between the two lines. The
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distance from the lesser trochanter to the proximal and distal fracture lines was also measured. If
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a single plain radiograph of the entire femur was not available, two plain radiographs that
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together showed the entire femur were evaluated measuring from the lesser trochanter and the
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femoral condyles to a stable structure, often a screw, present in both radiographs. The distance to
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the middle of the fracture was calculated from the measured distance to the proximal and distal
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fracture lines. All measurements were normalized to the total length of the femur.
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Analysis
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Statistical analysis was conducted with Microsoft Excel version 2007 (Microsoft,
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Redmond, WA). Unequal variance Student’s t tests were conducted to compare continuous data,
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including gunshot wound fracture location and continuous demographic data. For discrete data,
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Chi-squared or Fisher’s exact test, if the sample size in any box of the contingency table was less
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than five, was used to assess for significance. A P-value of 6, with a P-value < 0.05. Considering that we found the results to be the same
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whether the patients with femoral neck and intertrochanteric fractures were included or excluded,
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for the sake of simplicity, we reported the data from one methodology. We presented the data
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including the patients with femoral neck and intertrochanteric fractures to eliminate any
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confusion regarding whether these patients affected our results. This methodology slightly
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underestimates the location of these fractures by a few millimeters. The fractures are actually a
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few millimeters more proximal than the lesser trochanter, which makes it more difficult for the
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location of the fracture in the distal third of the femur to predict arterial injury.
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Although all results were statistically significant at P < 0.05, which is the medical
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standard for indication of statistical significance, confidence intervals were relatively wide.
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However, the statistical significance of these data suggests that location of ballistic femoral
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fractures can be used, with confidence, to predict presence of arterial injury.
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Our study had several strengths. The results were consistent regardless of which fracture
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extent (proximal extent, middle of fracture, or distal extent) was analyzed. To our knowledge,
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this study is the largest investigation of its type in the literature and provides the clinician with a
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useful clinical risk factor to aid in the evaluation of patients with femoral fractures after civilian
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gunshot wounds.
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Conclusions
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The results of the present study indicate that if a gunshot wound-related femoral fracture occurs in the distal third of the femur, it is approximately six times more likely to be associated
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with arterial injury. Practitioners should be aware that such gunshot wound fractures deserve
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particular attention, considering the gravity of the complications associated with delayed
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treatment of arterial injury.
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Figure Legends
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Fig. 1. Radiograph shows method of measuring fractures.
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Fig. 2. Frequency distribution for location of distal fracture line in ballistics-related fractures
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with and without arterial injury.
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Conflict of Interest Statement The authors have no potential conflicts of interest to report. No outside funding was received for this work.
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416 417 418
Acknowledgment We thank Senior Editor and Writer Dori Kelly, MA, for editing the manuscript.
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Table 1
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Characteristics of study participants Ballistic fracture with
Ballistic fracture without
arterial Injury
arterial injury
(n = 14)
(n = 119)
ip t
SD
Mean
Age (year)
27.3
9.4
27.3
Height (inch)
70.5
2.9
Weight (pound)
174.6
37.1
14 (100%) 0 (0%)
11 (79%)
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Race
0.99
70.3
8.3
0.85
177.9
33.8
0.77
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9.4
0.37
108 (91%) 11 (9%)
101 (85%)
White
3 (21%)
16 (13%)
Unknown
0 (0%)
2 (2%)
RTS_S
SD
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Female
M
Sex
cr
Mean
Male
P-value*
7
1.5
7.7
0.9
0.15
6.5
1.6
7.5
1
0.04†
24.1
13.7
12.9
7.2
0.009†
TRISS
0.8
0.3
1
0.2
0.1
Days in hospital
15.5
13.5
6.1
15.8
0.03†
RTS_A ISS
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SD, standard deviation; RTS_S, Revised Trauma Score measured at scene of injury; RTS_A,
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Revised Trauma Score measured at admission; ISS, Injury Severity Score; TRISS, Trauma and
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Injury Severity Score
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*Unequal variance, Student’s t test for continuous data, and Fisher’s exact test for discrete data.
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†Statistically significant.
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Table 2
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Mean location of fracture in femur Ballistic fracture with
Ballistic fracture without
arterial injury (n = 14)
arterial injury (n = 119)
Mean
95% Confidence
Mean
95% Confidence
location
interval
location
Proximal fracture line
0.53
0.48−0.58
0.29
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P-value*
0.27−0.3
0.009†
Middle of fracture line
0.67
0.62−0.73
0.44
0.42−0.46
0.019†
Distal fracture line
0.6
0.55−0.66
0.35−0.38
0.013†
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†Statistically significant.
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*Unequal variance, Student’s t test.
0.36
M
428
interval
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Table 3
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Odds ratios: Does a fracture located in the distal third of the femur predict arterial injury? 95% Confidence interval
P-value*
Proximal fracture line
5.63
1.7−18.6
0.008†
Middle of fracture line
3.96
1.27−12.37
Distal fracture line
6.72
1.78−25.44
†Statistically significant.
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0.003†
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*Fisher’s exact test.
0.02†
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Odds ratio
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Table 4
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Diagnostic test characteristics of a fracture in the distal third of the femur: Proximal fracture line
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present in distal third of femur 95% Confidence interval
Sensitivity
43
20−67
Specificity
88
86−91
Positive predictive value
30
14−47
Negative predictive value
93
90−96
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Table 5
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Diagnostic test characteristics of a fracture in the distal third of the femur: Distal fracture line
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present in distal third of femur 95% Confidence interval
Sensitivity
79
50−94
Specificity
65
61−67
Positive predictive value
21
13−25
Negative predictive value
96
91−99
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438
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Figure 1
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Figure 2
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S0020-1383(14)00258-7 http://dx.doi.org/doi:10.1016/j.injury.2014.05.020 JINJ 5750
To appear in:
Injury, Int. J. Care Injured
Received date: Revised date: Accepted date:
7-10-2013 2-5-2014 18-5-2014
Please cite this article as: Gitajn L, Perdue P, Hardcastle J, O’Toole RV, Location of Civilian Ballistic Femoral Fracture Indicates Likelihood of Arterial Injury, Injury (2014), http://dx.doi.org/10.1016/j.injury.2014.05.020 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Location of Civilian Ballistic Femoral Fracture Indicates Likelihood of Arterial Injury
Leah Gitajn, BS, Paul Perdue, BS, John Hardcastle, MD, and Robert V. O’Toole, MD
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From R Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
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Corresponding author:
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Robert V. O’Toole, MD
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R Adams Cowley Shock Trauma Center
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Department of Orthopaedics
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University of Maryland School of Medicine
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22 S. Greene Street, Suite T3R62
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Baltimore, MD 21201.
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Tel.: 410.328.6292; fax: 410.328.2893.
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E-mail address: [email protected]
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ABSTRACT
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Background: We evaluated whether the location of a ballistic femoral fracture helps predict the
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presence of arterial injury. We hypothesized that fractures located in the distal third of the femur
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are associated with a higher rate of arterial injury.
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Methods: We conducted a retrospective review of electronic medical records at our level I
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trauma centre and found 133 consecutive patients with femoral fractures from civilian gunshots
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from 2002 through 2007, 14 of whom sustained arterial injury. Fracture extent was measured
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with computerized viewing software and recorded with a standard technique, calculating
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proximal, distal, and central locations of the fracture as a function of overall length of the bone.
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Analyses were conducted with Student’s t, Chi-squared, and Fisher’s exact tests.
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Results: The location of any fracture line in the distal third of the femur was associated with
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increased risk of arterial injury (P < 0.05). The odds ratio for the presence of arterial injury when
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the proximal fracture line was in the distal third of the femur was 5.63 (95% confidence interval,
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1.7−18.6; P < 0.05) and when the distal fracture line was in the distal third of the femur was 6.72
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(95% confidence interval, 1.78−25.44; P < 0.05).
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Conclusions: A fracture line in the distal third of the femur after ballistic injury is six times
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more likely to be associated with arterial injury and warrants careful evaluation. Our data show
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that fracture location can help alert clinicians to possible arterial injury after ballistic femoral
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fracture.
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Introduction
Penetrating extremity trauma is commonly encountered at busy trauma centres, and diagnosing all injuries in a timely manner is critical. Of particular importance is the evaluation of
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vascular integrity after penetrating trauma. Rapid diagnosis of arterial injury is critical to prevent
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complications of prolonged limb ischemia, including compartment syndrome, arteriovenous
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fistula, ischemic contracture, and limb amputation.1,2
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Controversy exists regarding the appropriate diagnostic tools indicated in the setting of
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penetrating extremity trauma. Historically, all penetrating extremity trauma underwent surgical
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exploration. More recently, angiography has been used to diagnose vascular injury in all cases of
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extremity trauma.3−6 However, the necessity for angiography in all penetrating trauma cases has
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become controversial, and some data suggest that “hard” signs of vascular injury revealed by
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physical examination detect those vascular injuries that require immediate surgical repair
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rendering further imaging studies unnecessary. Hard signs include active hemorrhage, distal
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ischemia, and bruit or thrill over the wound.7
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Fractures that occur as a result of penetrating trauma deserve particular attention.
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Ballistic fractures are associated with a twofold higher rate of total vascular injury (both those
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that present with hard signs during physical examination and those without hard signs).8,9
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Additionally, the need for surgical repair of vascular injury is nearly doubled in cases of ballistic
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injury with fracture compared with cases of ballistic injury without fracture.8,9 Norman et al.9
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found a threefold increase in the incidence of arterial injuries that did not present with hard signs
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during physical examination (“subclinical” or “occult” injuries). Furthermore, the presence of
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fracture renders physical examination more challenging to perform and more difficult to
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interpret.10 Several possible reasons for the increased incidence of arterial injury in association 3 Page 3 of 30
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with ballistic fractures compared with other ballistic injuries include creation of a secondary
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bony missile and tethering of vascular structures to bone.11 Considering that plain radiographs are universally obtained of each patient suspected of
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having a fracture, this study was undertaken to determine whether the plain radiographs can be
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used to predict the presence of arterial injury in the setting of a femoral fracture resulting from a
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civilian gunshot. Considering that the superficial femoral artery is tethered to the femur as it
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passes through Hunter canal in the adductor hiatus, it is possible the fractures near that location
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are more likely to cause arterial injury. Therefore, we hypothesized that ballistic femoral
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fractures located in the distal third of the femur are more likely to be associated with arterial
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injury.
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Patients and methods
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Study group
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After approval from our institutional review board, we conducted a review of 2546
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patients who had sustained gunshot wounds and were admitted to our urban level I trauma centre
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from 2002 through 2007. Patients were identified with the use of a prospective trauma registry
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database.
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Each of the patients selected for the study met the inclusion criterion of having sustained
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a gunshot wound that resulted in a femoral fracture (n = 153). Eighteen patients were excluded
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because their plain radiographs did not contain the entire femur for measurement of femoral
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length, and two patients were excluded because they had sustained ballistic injuries from
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shotguns. Shotgun injuries were excluded because they are caused by a different mechanism of
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injury. A shotgun shell contains from a few to hundreds of pellets, leading to a very different
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injury pattern that is more similar to injury caused by high-velocity ballistics than injury caused
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by civilian gunshot.40 One of the patients who sustained a shotgun injury also sustained an
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arterial injury. The 133 remaining patients who sustained femoral fractures as a consequence of
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civilian gunshot wounds to the lower extremity were identified and comprised the study group.
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We reviewed all electronic medical records, including radiology reports, to determine the
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presence (n = 14, 11%) or absence (n = 119) of arterial injury in each patient. Arterial injury had
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been confirmed by angiography or computed tomographic (CT) angiography. Twelve of 14
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patients with arterial injury were treated with vascular repair. Of those with arterial injury, the
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superficial femoral artery was injured in eight (57%), the common femoral artery in one (7%),
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and the popliteal artery in five (36%). Two patients sustained arterial injuries that were not
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treated operatively because of minimal arterial wall disruption (intimal defects with intact distal
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circulation or pseudoaneurysm). Of the 20 excluded patients, two had vascular injuries.
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From our database, we retrieved demographic data on all patients in our study group,
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including patient age, sex, date and timing of injury, mechanism of injury, Revised Trauma
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Score (RTS) measured at the scene of injury and measured at admission, Injury Severity Score
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(ISS), Trauma and Injury Severity Score (TRISS), admission Glasgow Coma Scale score, blood
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pressure, heart rate, admission and discharge dates, number of days in the intensive care unit,
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scene time, injury type, method of injury, specific patterns of injury, and disposition. The data
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were used to ensure that the two study groups were similar demographically.
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No significant difference was shown between the patients with and without arterial injury
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regarding age, sex, race, mechanism of injury, diastolic blood pressure, respiratory rate,
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temperature, RTS at the scene, TRISS, admission Glasgow Coma Scale score, number of days
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spent in the intensive care unit, or scene time. However, a significant (P < 0.05) difference was
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shown between the two groups regarding systolic blood pressure, heart rate, RTS at admission,
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ISS, and days in hospital, as might be expected (Table 1).
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Radiographic Measurement
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Two of our co-authors who were blinded to the presence or absence of arterial injury
obtained measurements from the anteroposterior view postoperative radiographs of the femur.
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All fractures in this study had been treated with intramedullary nail insertion, and the nail was
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present in all images. Images were viewed with the use of IMPAX for Radiology software (Agfa
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HealthCare, Greenville, SC) on computerized workstations that are used at our institution for
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clinical viewing of radiographs on a picture archiving and communication system. The IMPAX
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Markup Caliper tool (Agfa HealthCare) was used to measure the length of the femur in
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millimeters.
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A standardized technique was used to measure each fracture (Fig. 1). One line was drawn
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perpendicular to the lesser trochanter and another across the most distal part of the femoral
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condyles. The length of the femur was recorded as the distance between the two lines. The
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distance from the lesser trochanter to the proximal and distal fracture lines was also measured. If
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a single plain radiograph of the entire femur was not available, two plain radiographs that
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together showed the entire femur were evaluated measuring from the lesser trochanter and the
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femoral condyles to a stable structure, often a screw, present in both radiographs. The distance to
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the middle of the fracture was calculated from the measured distance to the proximal and distal
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fracture lines. All measurements were normalized to the total length of the femur.
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Analysis
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Statistical analysis was conducted with Microsoft Excel version 2007 (Microsoft,
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Redmond, WA). Unequal variance Student’s t tests were conducted to compare continuous data,
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including gunshot wound fracture location and continuous demographic data. For discrete data,
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Chi-squared or Fisher’s exact test, if the sample size in any box of the contingency table was less
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than five, was used to assess for significance. A P-value of 6, with a P-value < 0.05. Considering that we found the results to be the same
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whether the patients with femoral neck and intertrochanteric fractures were included or excluded,
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for the sake of simplicity, we reported the data from one methodology. We presented the data
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including the patients with femoral neck and intertrochanteric fractures to eliminate any
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confusion regarding whether these patients affected our results. This methodology slightly
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underestimates the location of these fractures by a few millimeters. The fractures are actually a
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few millimeters more proximal than the lesser trochanter, which makes it more difficult for the
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location of the fracture in the distal third of the femur to predict arterial injury.
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Although all results were statistically significant at P < 0.05, which is the medical
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standard for indication of statistical significance, confidence intervals were relatively wide.
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However, the statistical significance of these data suggests that location of ballistic femoral
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fractures can be used, with confidence, to predict presence of arterial injury.
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Our study had several strengths. The results were consistent regardless of which fracture
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extent (proximal extent, middle of fracture, or distal extent) was analyzed. To our knowledge,
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this study is the largest investigation of its type in the literature and provides the clinician with a
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useful clinical risk factor to aid in the evaluation of patients with femoral fractures after civilian
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gunshot wounds.
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Conclusions
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The results of the present study indicate that if a gunshot wound-related femoral fracture occurs in the distal third of the femur, it is approximately six times more likely to be associated
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with arterial injury. Practitioners should be aware that such gunshot wound fractures deserve
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particular attention, considering the gravity of the complications associated with delayed
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treatment of arterial injury.
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Figure Legends
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Fig. 1. Radiograph shows method of measuring fractures.
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Fig. 2. Frequency distribution for location of distal fracture line in ballistics-related fractures
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with and without arterial injury.
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Conflict of Interest Statement The authors have no potential conflicts of interest to report. No outside funding was received for this work.
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Acknowledgment We thank Senior Editor and Writer Dori Kelly, MA, for editing the manuscript.
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Table 1
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Characteristics of study participants Ballistic fracture with
Ballistic fracture without
arterial Injury
arterial injury
(n = 14)
(n = 119)
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SD
Mean
Age (year)
27.3
9.4
27.3
Height (inch)
70.5
2.9
Weight (pound)
174.6
37.1
14 (100%) 0 (0%)
11 (79%)
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Race
0.99
70.3
8.3
0.85
177.9
33.8
0.77
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9.4
0.37
108 (91%) 11 (9%)
101 (85%)
White
3 (21%)
16 (13%)
Unknown
0 (0%)
2 (2%)
RTS_S
SD
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M
Sex
cr
Mean
Male
P-value*
7
1.5
7.7
0.9
0.15
6.5
1.6
7.5
1
0.04†
24.1
13.7
12.9
7.2
0.009†
TRISS
0.8
0.3
1
0.2
0.1
Days in hospital
15.5
13.5
6.1
15.8
0.03†
RTS_A ISS
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SD, standard deviation; RTS_S, Revised Trauma Score measured at scene of injury; RTS_A,
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Revised Trauma Score measured at admission; ISS, Injury Severity Score; TRISS, Trauma and
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Injury Severity Score
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*Unequal variance, Student’s t test for continuous data, and Fisher’s exact test for discrete data.
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†Statistically significant.
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Table 2
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Mean location of fracture in femur Ballistic fracture with
Ballistic fracture without
arterial injury (n = 14)
arterial injury (n = 119)
Mean
95% Confidence
Mean
95% Confidence
location
interval
location
Proximal fracture line
0.53
0.48−0.58
0.29
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P-value*
0.27−0.3
0.009†
Middle of fracture line
0.67
0.62−0.73
0.44
0.42−0.46
0.019†
Distal fracture line
0.6
0.55−0.66
0.35−0.38
0.013†
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†Statistically significant.
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*Unequal variance, Student’s t test.
0.36
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428
interval
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Table 3
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Odds ratios: Does a fracture located in the distal third of the femur predict arterial injury? 95% Confidence interval
P-value*
Proximal fracture line
5.63
1.7−18.6
0.008†
Middle of fracture line
3.96
1.27−12.37
Distal fracture line
6.72
1.78−25.44
†Statistically significant.
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0.003†
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*Fisher’s exact test.
0.02†
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Odds ratio
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Table 4
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Diagnostic test characteristics of a fracture in the distal third of the femur: Proximal fracture line
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present in distal third of femur 95% Confidence interval
Sensitivity
43
20−67
Specificity
88
86−91
Positive predictive value
30
14−47
Negative predictive value
93
90−96
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Table 5
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Diagnostic test characteristics of a fracture in the distal third of the femur: Distal fracture line
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present in distal third of femur 95% Confidence interval
Sensitivity
79
50−94
Specificity
65
61−67
Positive predictive value
21
13−25
Negative predictive value
96
91−99
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438
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Figure 1
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Figure 2
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