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One-year Mortality After Isolated Pelvic Fractures with Posterior Ring Involvement in Elderly Patients Jesse E. Bible, MD; Rishin J. Kadakia, BA; Adam Wegner, MD; Justin E. Richards, MD; Hassan R. Mir, MD
abstract Full article available online at Healio.com/Orthopedics. Search: 20130523-21 Previous 1-year mortality studies of pelvic fractures in elderly patients have focused on pubic rami fractures, in elderly patients with multiple injuries, or both. Baseline information on the 1-year mortality of isolated pelvic fractures in elderly patients is unavailable. The purpose of this study was to evaluate the 1-year mortality of elderly patients (aged 60 years or older) after isolated pelvic fractures with posterior ring involvement (Orthopaedic Trauma Association type 61-B and C). All patients aged 60 years or older treated for pelvic injuries at a single Level I trauma center over a 12-year period were retrospectively reviewed (N51223). Exclusion criteria were associated injuries to other body systems (Abbreviated Injury Scale greater than 2), ballistic injuries, long bone fractures, concurrent acetabular fractures, and type 61-A fractures or isolated pubic rami fractures without posterior involvement. Mortality data were obtained from the Social Security Death Index. Seventy patients met the inclusion criteria. Patients treated nonoperatively were significantly older compared with those treated operatively. However, the Charlson Comorbidity Index did not significantly differ between treatment groups. A significantly higher percentage of type-B fractures (83.0%) were treated nonoperatively compared with type-C fractures, which were treated operatively 88.2% of the time. Mortality rates at 3 and 6 months and 1 year postoperatively were 7.1%, 11.4%, and 12.9%, respectively. These results suggest that the 1-year mortality rates of isolated pelvic fractures in elderly patients are lower than those reported previously for hip fractures and pelvic fractures with concurrent injuries. Although age was identified as a significant variable differing between patients treated operatively vs nonoperatively, comorbidities were not. The authors are from the Vanderbilt Orthopaedic Institute, Nashville, Tennessee. The authors have no relevant financial relationships to disclose. The study was approved by Vanderbilt University Medical Center’s Institutional Review Board: Study #110715. Correspondence should be addressed to: Jesse E. Bible, MD, Department of Orthopaedic Surgery, Vanderbilt Orthopaedic Institute, Medical Center East, South Tower, Ste 4200, 1215 21st Ave S, Nashville, TN 37232-8774 (
[email protected]). doi: 10.3928/01477447-20130523-21
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Mortality After Isolated Pelvic Fractures | Bible et al
T
he elderly population represents a rapidly growing population with prolonged life expectancies, more active lifestyles, and a higher frequency of motorized vehicle use compared with previous generations.1-5 Due to these factors, an increasing number of elderly patients are sustaining pelvic fractures. Previous literature evaluating the long-term mortality of such fractures in elderly patients reported mixed findings. First, many authors combined acetabular and proximal femur fractures into the classification of pelvic fracture.1-5 Second, for studies that included only pelvic fractures, many authors did not separate isolated rami fractures from patients with posterior ring involvement (ie, sacral fractures, sacroiliac joint disruption, or both).1,3,4,6-8 Lastly, most studies included patients with significant acute injuries to other body systems and extremities, making the interpretation of these mortality rates difficult. Although it is challenging to account for all potential variables that affect long-term mortality, especially in elderly patients, excluding patients with other significant injuries allows for a better representation of the associated 1-year mortality of isolated pelvic fractures in elderly patients. Many pelvic ring injuries with posterior involvement once thought to be stable and treated nonoperatively in elderly patients have recently been treated surgically due to concern for mobilization and the prevention of possible late deformity. Although fractures with posterior involvement comprise a minority of fractures in the elderly, they can have a significant effect on an elderly patient’s life. Many of these fractures are treated conservatively due to perceived surgical risks. Baseline information on the long-term mortality of isolated pelvic fractures in elderly patients is needed to help guide decision making for the patient and surgeon. The purpose of this study was to evaluate the 1-year mortality of elderly patients (aged 60 years or older) after sustaining isolated pelvic fractures with posterior ring in-
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Table 1
Exclusion and Inclusion Criteria Exclusion Criteria Abbreviated injury score.2 Long bone fracturea
Inclusion Criteria Age 60 years or older Fracture/disruption of posterior pelvic ring (OTA type 61-B and C)
Acetabulum fracture Ballistic injury OTA type 61-A fractures (avulsion, iliac wing, and transverse fractures) Isolated pubic rami fractures without posterior involvement Abbreviation:OTA, Orthopaedic Trauma Association. a Defined as a fracture of the humerus, radius and ulna, femur, or tibia.
volvement (Orthopaedic Trauma Association [OTA] type 61-B and C).
Methods and Materials After obtaining institutional review board approval, a retrospective review was performed of all consecutive patients aged 60 years or older treated for pelvic ring fractures at a Level I academic center over a 12-year period (January 1998 to December 2009), which comprised 1223 patients. Patients with associated injuries to other body systems, as indicated by an Abbreviated Injury Scale of greater than 2, were excluded. Patients were further excluded if concurrent acetabular or long bone fractures were identified. Long bone fractures were defined as any injury to the humerus, radius and ulna, femur, or tibia. In addition, OTA type 61-A fractures (ie, avulsion, iliac wing, and transverse sacrum/coccyx fractures), isolated pubic rami fractures without evidence of posterior involvement seen on imaging, and ballistic injuries were excluded. The exclusion and inclusion criteria are shown in Table 1. Using admission pelvic radiographs and computed tomography scans, all fractures were classified by a fellowship-trained orthopedic trauma surgeon (H.R.M.) according to the Young and Burgess classification
system and the OTA classification system. Operative records and patient charts were reviewed for patient characteristics (ie, age, sex, body mass index [BMI], and smoking status). The Charlson Comorbidity Index (CCI) and age-adjusted CCI at the time of injury were calculated based on comorbidities obtained from patients’ clinical records and from administration International Classification of Diseases, Ninth Revision codes.9-11 The CCI and age-adjusted CCI are validated tools used to predict 1-year mortality rates in longitudinal clinical studies. The CCI is calculated by adding the coefficients assigned to comorbidities present at enrollment. One point is assigned to each of the following: myocardial infarction, congestive heart failure, peripheral vascular disease, dementia, chronic pulmonary disease, connective tissue disease, peptic ulcer disease, mild liver disease, and diabetes. Two points are assigned to hemiplegia, moderateto-severe renal disease, diabetes mellitus with organ damage, any tumor within 5 years of enrollment, lymphoma, and leukemia; 3 points are assigned to moderateto-severe liver disease; and 6 points are assigned to acquired immune deficiency syndrome and metastatic solid tumor. By adding age as an additional variable to
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Table 2
Patient and Injury Characteristics Total (n570)
Nonoperative (n546)
Operative (n524)
Pa,b
73.169.1 (60-92)
76.068.6 (60-91)
67.767.7 (60-92)
.000
57.1 (40)
41.3 (19)
87.5 (21)
.000
27.966.6 (19.5-54.6)
27.267.7 (19.5-54.6)
28.964.4 (20.1-33.9)
.414
14.3 (10)
13.0 (6)
16.7 (4)
.730
Charlson Comorbidity Index, mean6SD (range)
1.861.1 (0-8)
1.861.3 (0-8)
1.660.7 (0-3)
.863
Charlson Comorbidity Index, (age-adjusted), mean6SD (range)
4.661.4 (2-10)
5.061.5 (2-10)
4.061.0 (2-6)
.008
5.7 (4)
8.7 (4)
0 (0)
.291
22.9 (16)
26.1 (12)
16.7 (4)
.550
Patient and Injury Characteristics Age, y, mean6SD (range) Male sex, % (No.) BMI, mean6SD (range) Smoker, % (No.)
Prior hip/pelvic/acetabular instr/arthroplasty, % (No.) Injury mechanism, % (No.) Motor vehicle collision Motorcycle
5.7 (4)
0 (0)
16.7 (4)
.012
Pedestrian struck
7.1 (5)
8.7 (4)
4.2 (1)
.654
Tractor rollover
10.0 (7)
8.7 (4)
12.5 (3)
.684
Fall from height
21.4 (15)
17.4 (8)
29.2 (7)
.358
Ground level fall
22.9 (16)
34.8 (16)
0 (0)
.001
Industrial crush
10.0 (7)
4.3 (2)
20.8 (5)
.042
1.4 (1)
0 (0)
4.2 (1)
.343
LC I
52.9 (37)
78.3 (36)
4.2 (1)
.000
LC II
12.9 (9)
8.7 (4)
20.8 (5)
.257
LC III
1.4 (1)
2.2 (1)
0 (0)
1.000
APC I
2.9 (2)
4.3 (2)
0 (0)
.543
APC II
7.1 (5)
2.2 (1)
16.7 (4)
.044
APC III
Open fracture, % (No.) Young and Burgess, % (No.)
15.7 (11)
0 (0)
45.8 (11)
.000
VS
1.4 (1)
2.2 (1)
0 (0)
1.000
CM
5.7 (4)
2.2 (1)
12.5 (3)
.113
OTA (61), % (No.) B1
10.0 (7)
6.5 (3)
16.7 (4)
.221
B2
64.3 (45)
87.0 (40)
20.8 (5)
.000
B3
1.4 (1)
2.2 (1)
0 (0)
1.000
C1
12.9 (9)
4.3 (2)
29.2 (7)
.006
C2
11.4 (8)
0 (0)
33.3 (8)
.000
C3
0 (0)
0 (0)
0 (0)
1.000
34.3 (24)
–
100 (24)
–
–
–
1.461.4 (0-6)
–
Length of stay, d, mean6SD (range)
5.263.3 (0-19)
4.162.1 (0-11)
7.164.2 (3-19)
.002
Follow-up, mo, mean6SD (range)
8.3615.9 (0-95)
4.667.9 (0-37)
14.664.7 (0-95)
.009
Surgery performed on fracture, % (No.) Time from admission to surgery, d, mean6SD (range)
Abbreviation: BMI, body mass index. a P values represent the comparisons between the nonoperative and operative treatment groups. b Bolded data are statistically significant.
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Mortality After Isolated Pelvic Fractures | Bible et al
predict mortality, an age-adjusted CCI can be calculated by adding 1 point for each decade after the age of 50 years; up to 6 points can be added for patients 100 years or older. Death and date of death were extracted for each patient from the Social Security Administration Death Master File (Social Security Death Index).12-15 A combination of Social Security number, full name, date of birth, and place of birth was used to maximize data accuracy.16,17 Mortality rates were calculated at the following time points after injury: in-hospital and 3 and 6 months and 1 year after injury. No data censoring was needed because the injuries up to the year 2009 were assessed over 2 years later for 1-year or less mortality rates. Patient and injury characteristics and mortality rates for patients treated operatively vs nonoperatively were compared. Using SPSS version 20.0 software (SPSS, Inc, Chicago, Illinois), dichotomous data were compared using Fisher’s exact tests, and independent t tests and Mann-Whitney U tests were used for comparisons of parametric and nonparametric data, respectively. Statistical significance was set at a P value less than .05.
Results Seventy patients met the inclusion criteria. Average age was 73.169.1 years, and 57.1% (n540) of the patients were men. According to the Young and Burgess classification, the most common fracture patterns were LC I (n537; 52.9%), APC III (n511; 15.7%), and LC II (n59; 12.9%). According to the OTA Classification System, the most common fracture patterns were 61-B2 (n545; 64.3%), C1 (n59; 12.9%), C2 (n58; 11.4%), and B1 (n57; 10.0%). Motor vehicle collision and groundlevel fall were the most common injury mechanisms (n516; 22.9% each), with fall from height being the next most frequent (n515; 21.4%) (Table 2).
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Table 3
Mortality Rates at Various Time Pointsa % (Absolute No.) Mortality Rate
Total (n570)
Nonoperative (n546)
Operative (n524)
P
In-hospital
5.7 (1.9)
6.5 (3)
4.2 (1)
1.000
3 mo
7.1 (5)
8.7 (4)
4.2 (1)
.654
6 mo
11.4 (8)
13.0 (6)
8.3 (2)
.706
1y
12.9 (9)
15.2 (7)
8.3 (2)
.709
1 y postdischargeb
7.6 (5)
9.3 (4)
4.3 (1)
.651
a
Represents the mortality rate of patients discharged after the initial injury.
Twenty-four (34.3%) fractures were treated operatively. Patients treated nonoperatively were significantly older compared with those treated operatively (76.068.6 vs 67.767.7 years, respectively; P5.0001). However, the Charlson Comorbidity Index did not differ statistically between treatment groups (P5.863). Not surprising, a significantly higher percentage of pelvic fractures treated nonoperatively were the result of a ground-level fall (34.8% nonoperative vs 0% operative patients; P5.001). LC I fractures were most commonly treated nonoperatively, whereas APC II and III fractures were most commonly treated operatively (P5.0001-.044). Mortality rates while in-hospital, and at 3 and 6 months and 1 year after injury were 5.7%, 7.1%, 11.4%, and 12.9%, respectively (Table 3). Four in-hospital deaths occurred; the 1-year mortality rate of the 66 discharged patients was 7.6%. No significant differences in mortality rates were seen between operative and nonoperative patients across all time points (P5.651-1.000).
Discussion The mortality following hip fractures in elderly patients has been extensively studied, with the 1-year mortality rates ranging from 19% to 50%.12,18,19 These data have occasionally been applied to
pelvic fractures to help guide treatment decisions in elderly patients. One-year mortality rates of pelvic fractures have been reported to range from 13%. to 27%.4,6,20 Each of these studies’ classifications of a pelvic fracture remains heterogeneous. Hill et al6 reported a 13% mortality rate when looking only at pubic rami fractures; conversely, Leung et a20 included acetabular fractures and reported a 12% rate. Morris et al4 did not provide a fracture breakdown of fractures in elderly patients, but reported a 1-year mortality rate of 27%. The current findings indicate that the 1-year mortality rate following a pelvic fracture in an elderly patient is less than that of a hip fracture. When directly comparing the current results with those from other hip fracture studies in elderly patients,12,18,19 a significantly lower overall 1-year mortality rate was found (P5.003-.03) However, because posterior ring involvement has become a more significant deciding factor in treatment decisions, baseline information is needed on the 1-year mortality associated with such injuries. The authors found a 12.9% mortality rate 1 year after a posterior ring injury in elderly patients. For discharged patients, a 7.6% mortality rate was seen at 1 year after injury. These mortality rates were lower than the previously reported rates, which was not surprising because
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the current study excluded patients with concurrent traumatic injuries. Due to perceived surgical risks in the elderly population, many unstable fractures are treated nonoperatively with the presumption that this route leads to a decreased mortality rate. Although the current study only included a univariate analysis of 2 heterogeneous groups, the data did not support this presumption. With a better appreciation for the importance of early mobilization for elderly patients following an injury, these findings are also not entirely unexpected becausepelvic fixation can reduce pain and improve early mobilization. Both groups varied significantly in regards to age and injury mechanism but not the CCI, limiting the conclusions that could be drawn from direct comparison. Furthermore, it was not statistically feasible to control for the multiple variables that could affect 1-year mortality in elderly patients, especially considering that only 9 deaths occurred. However, the purpose of this study was to assess the 1-year mortality of all such injuries, not to specifically to determine the treatment course that leads to a reduced mortality because a true homogenous comparison between operative and nonoperative patients in this population would be nearly impossible. This study had additional limitations. The authors did not account for other variables that could alter long-term mobility. Preinjury ambulation or independence status was not recorded, which undoubtedly contributes to recovering from such an injury. This information would make any mortality comparison hold more power. However, it does not distract from the primary purpose of this study in determining the 1-year mortality across all isolated posterior pelvic ring injuries, which has not been previously reported in the literature. Lastly, the small sample
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size (n570) limited the conclusions that could be drawn (even after reviewing 1223 elderly patients with pelvic fractures).
7. Koval KJ, Aharonoff GB, Schwartz MC, et al. Pubic rami fracture: a benign pelvic injury? J Orthop Trauma. 1997; 11(1):7-9.
Conclusion
9. Charlson M, Szatrowski TP, Peterson J, Gold J. Validation of a combined comorbidity index. J Clin Epidemiol. 1994; 47(11):1245-1251.
The 1-year mortality rates for elderly patients with isolated pelvic fractures in the current study are lower than those reported previously for hip fractures and pelvic fractures with concurrent injuries. The majority of patients with OTA type B injuries were treated nonoperatively, whereas the majority of patients with OTA type C injuries were treated operatively, with no difference in mortality. Although age was identified as a significant variable differing between patients treated operatively vs nonoperatively, medical comorbidities were not. This information can be useful for surgical decision making and for counseling patients and families.
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8. Rossvoll I, Finsen V. Mortality after pelvic fractures in the elderly. J Orthop Trauma. 1989; 3(2):115-117.
10. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis. 1987; 40(5):373-383. 11. Deyo RA, Cherkin DC, Ciol MA. Adapting a clinical comorbidity index for use with ICD-9-CM administrative databases. J Clin Epidemiol. 1992; 45(6):613-619. 12. Dy CJ, Dossous PM, Ton QV, Hollenberg JP, Lorich DG, Lane JM. Does a multidisciplinary team decrease complications in male patients with hip fractures? Clin Orthop Relat Res. 2011; 469(7):1919-1924. 13. Quinn J, Kramer N, McDermott D. Validation of the Social Security Death Index (SSDI): an important readily-available outcomes database for researchers. West J Emerg Med. 2008; 9(1):6-8. 14. Administration SS. Social Security death index. RootsWeb Web site. http://ssdi.rootsweb. ancestry.com. Accessed January 20, 2012. 15. Streubel PN, Ricci WM, Wong A, Gardner MJ. Mortality after distal femur fractures in elderly patients. Clin Orthop Relat Res. 2010; 469(4):1188-1196. 16. Cowper DC, Kubal JD, Maynard C, Hynes DM. A primer and comparative review of major US mortality databases. Ann Epidemiol. 2002; 12(7):462-468. 17. Fillenbaum GG, Burchett BM, Blazer DG. Identifying a national death index match. Am J Epidemiol. 2009; 170(4):515-518. 18. Gregory JJ, Kostakopoulou K, Cool WP, Ford DJ. One-year outcome for elderly patients with displaced intracapsular fractures of the femoral neck managed non-operatively. Injury. 2010; 41(12):1273-1276. 19. Haentjens P, Autier P, Barette M, Venken K, Vanderschueren D, Boonen S. Survival and functional outcome according to hip fracture type: a one-year prospective cohort study in elderly women with an intertrochanteric or femoral neck fracture. Bone. 2007; 41(6):958-964. 20. Leung WY, Ban CM, Lam JJ, Ip FK, Ko PS. Prognosis of acute pelvic fractures in elderly patients: retrospective study. Hong Kong Med J. 2001; 7(2):139-145.
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