Traumatic sternal injury in patients with rib fracture: A single-center experience.

PURPOSE: We aimed to assess the pattern and impact of sternal injury with rib fracture in a Level 1 trauma center. PATIENTS AND METHODS: We conducted a retrospective review of trauma registry data to identify patients who presented with sternal fracture between 2010 and 2017. Data were analyzed and compared in patients with and without rib fracture.
RESULTS: We identified 212 patients with traumatic sternal injury, of them 119 (56%) had associated rib fractures. In comparison to those who had no rib fracture, patients with rib fractures were older (40.1 ± 13.6 vs. 37.8 ± 14.5), were frequently involved in traffic accidents (75% vs. 71%), had higher chest abbreviated injury scale (AIS 2.8 ± 0.6 vs. 2.2 ± 0.5) and Injury Severity Score ( ISS 17.5 ± 8.6 vs. 13.3 ± 9.6), were more likely to be intubated (33% vs. 19%), required chest tube insertion (13.4% vs. 4.3%), and received blood transfusion (29% vs. 17%). Rates of spine fracture, head injury, and solid organ injury were comparable in the two groups. Manubrium, clavicular and scapular fractures, lung contusion, hemothorax, and pneumothorax were significantly more evident in those who had rib fractures. Hospital length of stay was prolonged in patients with rib fractures (P = 0.008). The overall mortality was higher but not statistically significant in patients with rib fractures (5.0% vs. 3.2%).
CONCLUSIONS: Sternal fractures are rare, and detection of associated injuries requires a high index of suspicion. Combined sternal and rib fractures are more evident in relatively older patients after chest trauma. This combination has certain clinical implications that necessitate further prospective studies.

INTRODUCTION

Sternal fracture results from direct impact to the anterior chest wall; it occurs in 4% of motor vehicle crash (MVC) victims and 3%–8% of blunt thoracic trauma cases.[12] Sternal fracture is usually associated with high-energy trauma, as a consequence of a significant direct external force or as a result of vertebral compression and flexion of the chest.[3] Implementation of seat belt use led to an increased survival, along with an increased incidence of traumatic sternal fracture.[45] This increase can also be attributed to the use of advanced diagnostic tools (ultrasound and computed tomography [CT]) in the trauma room. Even with the increase in sternal fractures, the overall incidence is still low (1%–7%).[67] Given that they are relatively rare, few studies about sternal fractures are seen in the literature.[8] Sternal fractures involve disruption of the cortex as a result of direct impact to the chest. They are usually transverse fractures, at the manubrium or body of the sternum. They can be simple, undisplaced, or comminuted with overlapping fragments.[91011] Sternal fractures can be isolated but are usually associated with underlying organ trauma.[1011] They reflect a significant mechanism; therefore, more serious occult injuries should always be suspected.[12] Several studies have discussed the frequency of associated injuries such as soft-tissue contusions, rib fractures, pneumothorax, spinal injury, and cardiac injuries.[13] Management requires attention to the important underlying structures such as the heart, great vessels, respiratory tract, and spine.

Most of the studies in the Middle East region are single-institution reviews. Therefore, we conducted this retrospective study to look at the incidence, diagnostic approach, management, morbidity, and mortality associated with sternal fractures in all patients admitted to our Level 1 trauma center with fractured sternum during the period between 2010 and 2017. We sought to study the characteristics of sternal fractures (with and without rib fractures) and their associated injuries to further improve the diagnosis and management.

PATIENTS AND METHODS

The records of all patients who sustained sternal fractures between June 2010 and May 2017 were analyzed retrospectively. Data were collected from the prospectively collected trauma registry of the Hamad Trauma Center (HTC), the national trauma center of Qatar. The HTC trauma registry is a database that participates in both the National Trauma Data Bank (NTDB) and the Trauma Quality Improvement Program of the American College of Surgeons’ Committee on Trauma. The demographics (age and gender), mechanism of injury, clinical variables (blood pressure, heart rate [HR], Glasgow Coma Scale, chest Abbreviated Injury Severity [AIS], and troponin level), Injury Severity Score (ISS), intra- and extrathoracic-associated injuries, site of sternal fracture, intubation, chest tube insertion, thoracotomy, blood transfusion, complications, treatment, hospital and intensive care unit (ICU) length of stay (LOS), ventilatory days, clinical follow-up days, and mortality were recorded. All patients initially managed using ATLS guidelines. Data were analyzed and compared in patients with and without rib fracture. The main outcome measures were mortality, hospital LOS, time spent in the ICU, and the duration of mechanical ventilation (ventilatory days). The study has been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendment and was approved by the Institutional Review Board, Hamad Medical Corporation (IRB# 17234/17), Doha. This observational retrospective study was reported according to the STROBE checklist [Supplement Table 1].

Supplement Table 1

STROBE statement: Checklist of items that should be included in reports of observational studies

Section/Topic	Item number	Recommendation	Reported on page number
Title and abstract	1	Indicate the study’s design with a commonly used term in the title or the abstract	1, 2
Introduction
Background/rationale	2	Explain the scientific background and rationale for the investigation being reported	3
Objectives	3	State specific objectives, including any prespecified hypotheses	4
Methods			4, 5
Study design	4	Present key elements of study design early in the paper	4
Setting	5	Describe the setting, locations, and relevant dates, including periods of recruitment, exposure, follow-up, and data collection	4, 5
Participants	6	(a) Cohort study - Give the eligibility criteria and the sources and methods of selection of participants. Describe methods of follow-up	4, 5
		Case-control study - Give the eligibility criteria and the sources and methods of case ascertainment and control selection. Give the rationale for the choice of cases and controls
		Cross-sectional study - Give the eligibility criteria and the sources and methods of selection of participants
		(b) Cohort study - For matched studies, give matching criteria and number of exposed and unexposed
		Case-control study - For matched studies, give matching criteria and the number of controls per case
Variables	7	Clearly define all outcomes, exposures, predictors, potential confounders, and effect modifiers. Give diagnostic criteria, if applicable	4,5
Data sources/measurement	8*	For each variable of interest, give sources of data and details of methods of assessment (measurement). Describe comparability of assessment methods if there is more than one group
Bias	9	Describe any efforts to address potential sources of bias
Study size	10	Explain how the study size was arrived at
Quantitative variables	11	Explain how quantitative variables were handled in the analyses. If applicable, describe which groupings were chosen and why
Statistical methods	12	(a) Describe all statistical methods, including those used to control for confounding
		(b) Describe any methods used to examine subgroups and interactions
		(c) Explain how missing data were addressed
		(d) Cohort study - If applicable, explain how loss to follow-up was addressed	5
		Case-control study - If applicable, explain how matching of cases and controls was addressed
		Cross-sectional study - If applicable, describe analytical methods taking account of sampling strategy
		(e) Describe any sensitivity analyses
Results			5-7
Participants	13*	(a) Report numbers of individuals at each stage of study - e.g., numbers potentially eligible, examined for eligibility, confirmed eligible, included in the study, completing follow-up, and analyzed
		(b) Give reasons for nonparticipation at each stage
Descriptive data	14*	(a) Give characteristics of study participants (e.g. demographic, clinical, and social) and information on exposures and potential confounders
		(b) Indicate number of participants with missing data for each variable of interest
		(c) Cohort study - Summarize follow-up time (e.g., average and total amount)
Outcome data	15*	Cohort study - Report numbers of outcome events or summary measures over time
		Case-control study - Report numbers in each exposure category or summary measures of exposure
		Cross-sectional study - Report numbers of outcome events or summary measures
Main results	16	(a) Give unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (e.g., 95% CI). Make clear which confounders were adjusted for and why they were included
		(b) Report category boundaries when continuous variables were categorized
Other analyses	17	Report other analyses done - e.g., analyses of subgroups and interactions and sensitivity analyses
Discussion			7-11
Key results	18	Summarize key results with reference to study objectives
Limitations	19	Discuss limitations of the study, taking into account sources of potential bias or imprecision. Discuss both direction and magnitude of any potential bias
Interpretation	20	Give a cautious overall interpretation of results considering objectives, limitations, multiplicity of analyses, results from similar studies, and other relevant evidence
Generalizability	21	Discuss the generalizability (external validity) of the study results
Other information
Funding	22	Give the source of funding and the role of the funders for the present study and, if applicable, for the original study on which the present article is based	13

http://www.plosmedicine.org/, Annals of Internal Medicine at http://www.annals.org/, and Epidemiology at http://www.epidem.com/). Information on the STROBE Initiative is available at www.strobe-statement.org

Statistical analysis

Data were presented as proportions, medians, or mean ± standard deviation, as appropriate.

We categorized patients into two groups, i.e., no rib fracture and with rib fracture. Differences in categorical and continuous variables were analyzed using Chi-square test and Student's t-test, as appropriate. Yates’ corrected Chi-square was used for categorical variables if the expected cell frequencies were below 5. A two-tailed P < 0.05 was considered to be statistically significant. All data analyses were carried out using the Statistical Package for the Social Sciences, version 18 (SPSS Inc., Chicago, IL, USA).

RESULTS

Across the study duration, there were 212 patients with sternal fracture, of whom 119 patients had rib fracture (56%). Table 1 shows the demographic and clinical parameters of patients. The mean age in our study group was 38.3 ± 15.1 years, and 93% of patients were male. Patients with rib fractures were older (40.1 ± 13.6 vs. 37.8 ± 14.5 years), but the two groups were comparable with regard to gender (P = 0.82). When the etiology of the trauma was classified, it was found that road traffic accidents were the most common mechanism of injury (73.1%), followed by falls (16%), fall of heavy objects (4.2%), and All-Terrain vehicle (ATV) crashes (2.8%). Patients with rib fractures were more frequently injured by traffic accidents and fall of heavy objects (P = 0.04) whereas those without rib fracture sustained higher fall-related injuries (P = 0.04).

Table 1

Characteristics of sternal fracture patients sustained rib versus no rib fractures

	Overall (n=212)	No rib fracture (44%)	With rib fracture (56%)	P
Age	38.3±15.1	37.8±14.5	40.1±13.6	0.32
Males, n (%)	197 (92.9)	86 (92.5)	111 (93.3)	0.82
Mechanism of injury, n (%)
Traffic accidents	155 (73.1)	66 (71.0)	89 (74.8)	0.04 for all
Fall from height	34 (16.0)	20 (21.5)	14 (11.8)
ATV crashes	6 (2.8)	3 (3.2)	3 (2.5)
Fall of heavy objects	9 (4.2)	1 (1.1)	8 (6.7)
Self-inflected	2 (0.9)	2 (2.2)	0 (0.0)
Others	6 (2.8)	1 (1.1)	5 (4.2)
Seat belt	73 (47.1)	36 (54.5)	37 (41.6)	0.24
Airbag	10 (6.5)	6 (9.1)	4 (4.5)	0.29
ED systolic BP	128±22	128.7±22.8	126.7±20.8	0.53
ED diastolic BP	79±15	81.3±16.8	76.6±13.7	0.03
ED HR	93.4±19	89.9±18.4	96.2±19.5	0.01
ED GCS	13.4±3.9	13.6±3.6	13.2±3.2	0.54
Chest AIS	2.56±0.6	2.2±0.5	2.8±0.6	0.001
ISS	16±9	13±10	17±8	0.001
Echocardiography, n (%)	33 (16.0)	9 (10.3)	24 (20.2)	0.05
Troponin positive, n (%)	46 (35.1)	19 (30.6)	27 (39.1)	0.31

GCS: Glasgow Coma Scale, AIS: Abbreviated Injury Severity, ISS: Injury severity scoring, HR: Heart rate, BP: Blood pressure, ATV: All-Terrain vehicle, ED: Emergency department

Most of the study population had moderate to serious chest injuries, with a mean chest AIS of 2.56 ± 0.6. The mean ISS (17.5 ± 8.6 vs. 13.3 ± 9.6; P = 0.001) and chest AIS (2.8 ± 0.6 vs. 2.2 ± 0.5 P = 0.001) were significantly higher in rib fracture group. Patients with rib fractures had lower diastolic pressure (P = 0.03) and higher HR (P = 0.01) in the emergency department. Although there was no significant difference in the troponin status between the two groups, patients with rib fractures were more likely to have positive troponin values (39.1% vs. 30.6%; P = 0.31).

The proportion of patients with lung contusion (43% vs. 19%), hemothorax (16% vs. 3.2%), and pneumothorax (33.6% vs. 5.4%) was significantly higher in the rib fracture group in comparison to those who had no rib fractures [Table 2].

Table 2

Comparison of thoracic and extrathoracic injuries

	Overall (%)	No rib fracture (%)	With rib fracture (%)	P
Vertebral fracture
Cervical fracture	12 (5.7)	4 (3.3)	8 (6.7)	0.44
Thoracic fracture	30 (14.2)	11 (11.8)	19 (16.0)	0.39
Lumbar fracture	4 (1.9)	0 (0.0)	4 (3.4)	0.07
Retrosternal hematoma	31 (14.6)	13 (14.0)	18 (15.1)	0.81
Lung contusion	69 (32.5)	18 (19.4)	51 (42.9)	0.001
Hemothorax	22 (10.4)	3 (3.2)	19 (16.0)	0.003
Right	13 (59.1)	2 (66.7)	11 (57.9)	0.53 for all
Left	4 (18.2)	1 (33.3)	3 (15.8)
Bilateral	5 (22.7)	0 (0.0)	5 (26.3)
Pneumothorax	45 (21.2)	5 (5.4)	40 (33.6)	0.001
Right	19 (42.2)	3 (60.0)	16 (40.0)	0.42 for all
Left	16 (35.6)	2 (40.0)	14 (35.0)
Bilateral	10 (22.2)	0 (0.0)	10 (25.0)
Hemopneumothorax	18 (8.5)	4 (4.3)	14 (11.8)	0.05
Right	5 (27.8)	1 (25.0)	4 (28.6)	0.54 for all
Left	10 (55.6)	3 (75.0)	7 (50.0)
Bilateral	3 (16.7)	0 (0.0)	3 (21.4)
Associated injuries
Head	37 (17.5)	18 (19.4)	19 (16.0)	0.51
Spleen	9 (4.2)	1 (1.1)	8 (6.7)	0.04
Liver	19 (9.0)	6 (6.5)	13 (10.9)	0.25
Bowel	8 (3.8)	3 (3.2)	5 (4.2)	0.71
Spine	93 (43.9)	34 (36.6)	59 (49.6)	0.05

The most common extrathoracic-associated injuries were spine injuries (44%). 14.2% had a thoracic vertebral fracture, 5.7% had cervical vertebral injury, and 1.9% had lumbar spine fracture. 17.5% had associated head injury and 9% had liver injury. The rates of spine fracture, head injury, and solid organ injury were comparable in the two groups.

Table 3 shows the sternal fractures with adjacent injuries. The most common intrathoracic injuries were scapular (10.4%) (left 40.9%, right 36.4%, and bilateral 22.7%) and clavicular fractures (9.4%) (right 50%, left 35%, and bilateral 15%) which were significantly higher in patients with rib fracture (P = 0.001). Injury to the thoracic aorta accounted for only 6 (2.8%) cases, and pericardial injury was seen in 0.9% of cases.

Table 3

Comparison of thoracic injuries and management in patients with and without rib fracture

	Overall (%)	No rib fracture (%)	With rib fracture (%)	P
Thoracic injuries
Pericardial	2 (0.9)	2 (2.2)	0 (0.0)	0.10
Thoracic aorta	6 (2.8)	1 (1.1)	5 (4.2)	0.17
Site of sternal fracture*
Manubrium	72 (35.1)	24 (27.3)	48 (41.0)	0.04
Upper sternum	33 (16.1)	17 (19.3)	16 (13.7)	0.27
Middle sternum	86 (42.0)	44 (50.0)	42 (35.9)	0.04
Lower sternum	28 (13.7)	11 (12.5)	17 (14.5)	0.67
Clavicular fracture	20 (9.4)	1 (1.1)	19 (16.0)	0.001
Right	10 (50.0)	0 (0.0)	10 (52.6)	0.37 for all
Left	7 (35.0)	1 (100)	6 (31.6)
Bilateral	3 (15.0)	0 (0.0)	3 (15.8)
Scapular fracture	22 (10.4)	3 (3.2)	19 (16.0)	0.003
Right	8 (36.4)	2 (66.7)	6 (31.6)	0.42 for all
Left	9 (40.9)	1 (33.3)	8 (42.1)
Bilateral	5 (22.7)	0 (0.0)	5 (26.3)
Treatment (n=122)
Conservative	72 (59.0)	30 (65.2)	42 (55.3)	0.03 for all
Orthopedic surgery	24 (19.7)	4 (8.7)	20 (26.3)
Spine fixation	10 (8.2)	5 (10.9)	5 (6.6)
Abdomen	4 (3.3)	1 (2.2)	3 (3.9)
Thoracic	4 (3.3)	0 (0.0)	4 (5.3)
Head	2 (1.6)	2 (4.3)	0 (0.0)
Maxillofacial	1 (0.8)	0 (0.0)	1 (1.3)
Superficial wound suture	4 (3.3)	3 (6.5)	1 (1.3)
Tracheostomy	1 (0.8)	1 (2.2)	0 (0.0)

*Overlap of sites of sternal fractures

The predominant sternal fracture locations were the middle sternum (42.0%) and the manubrium sterni (35.1%). Fractures of the upper as well as lower part of the corpus sterni were seen in 16.1% and 13.7% of cases, respectively. The two groups were comparable for sternal fracture location except manubrium sterni which was significantly associated with rib fracture (41.0% vs. 27.3%; P = 0.04). Clavicular and scapular fractures were significantly more evident with those who had rib fractures. With regard to management, 59% of cases were treated conservatively. The remaining cases underwent surgical intervention mainly for orthopedic (19.7%) and spinal procedures (8.2%); thoracic surgery was performed in 3.3% of patients (P = 0.03).

Table 4 demonstrates the hospital course and outcomes of sternal fracture cases. Four patients needed thoracotomy (1.9%). Patients with rib fractures were more likely to be intubated (33% vs. 19%; P = 0.02), to have chest tube insertion (13.4% vs. 4.3%; P = 0.02), and to receive blood transfusion (29% vs. 17%; P = 0.05) and were at higher risk of cardiac arrest (5.9% vs. 3.2%). The median ICU (8 [1-58] vs. 6 [1-44]; P = 0.91) and hospital (7 [1-145] vs. 3 [1-90]; P = 0.008) LOS was prolonged in patients with rib fractures. The overall inhospital mortality was 4.2% (9/212). The mortality was higher but not statistically significant in patients with rib fractures (5.0% vs. 3.2%; P = 0.51).

Table 4

Inhospital course and outcomes

	Overall	No rib fracture	With rib fracture	P
Intubation (%)	57 (26.9)	18 (19.4)	39 (32.8)	0.02
Chest tube (%)	20 (9.4)	4 (4.3)	16 (13.4)	0.02
Thoracotomy (%)	4 (1.9)	1 (1.1)	3 (2.5)	0.44
Blood transfusion (%)	50 (23.6)	16 (17.2)	34 (28.6)	0.05
Blood units transfused	6.5 (1-44)	6 (1-22)	7 (1-44)	0.28
ISS	15.6±9.3	13.3±9.6	17.5±8.6	0.001
Ventilator days	6 (1-43)	5 (1-43)	6 (1-29)	0.91
ICU LOS	7.5 (1-58)	6 (1-44)	8 (1-58)	0.91
Hospital LOS	5 (1-145)	3 (1-90)	7 (1-145)	0.008
Cardiac arrest	10 (4.7)	3 (3.2)	7 (5.9)	0.36
Paraplegia (%)	2 (0.9)	1 (1.1)	1 (0.8)	0.86
Mortality (%)	9 (4.2)	3 (3.2)	6 (5.0)	0.51
Follow-up days	209.1 (1-2621)	134 (1-2573)	235 (1-2621)	0.28

ICU: Intensive care unit, LOS: Length of stay, ISS: Injury Severity Score

DISCUSSION

This study aims to assess the incidence and pattern of sternal fracture with its associated injuries in a single institute with a Level 1 trauma center. We identified 212 patients with traumatic sternal injury across the study period in a center with total of 1500–1700 trauma admissions per year. In comparison to those who had no rib fracture, patients’ sternal and rib fractures were older and had higher ISS, chest AIS, and hospital LOS. Clavicular and scapular fractures, lung contusion, hemothorax, and pneumothorax were also more evident in those patients.

Road traffic accidents have been reported to account for 66%–83% of sternal fractures, followed by falls and assault.[1114] The incidence of sternal fractures has increased over the past decade; in general, it has been reported as 3–7 in MVCs.[515] Sternal fracture is also known as a typical “seat belt trauma.”[1116] Other reported risk factors for sternal fracture include advanced age and being a front seat passenger.[1] Many believe that the morbidity is attributable to the associated life-threatening injuries (thoracic, pulmonary, cardiac, and spinal injuries) rather than the sternal fracture per se.[17] Sternal fractures are associated with higher morbidity and mortality in older patients.

Schulz-Drost et al. showed that patients with a sternal fracture in addition to a flail chest had longer hospital and ICU stay and ventilator days than those without sternal fracture.[18] Sternal fracture is also associated with cardiac and thoracic spine injuries. Associated injuries have been reported in around 60% of sternal fractures with a mortality rate of 25%–45%.[1519] The variation in the outcome rates across studies could be attributed to the patient age, time for diagnosis, the use of early CT scan imaging, type and severity of associated injuries, and the aggressive monitoring and management plan.[1420] In data extracted from the NTDB, Oyetunj et al.[9] reported a crude mortality of 7.9%. In this study, one-third of cases had associated lung contusion and 59% had rib fractures. Our data, which also reported to the NTDB, showed relatively less mortality (4.2%) but with almost the same rates of lung contusion and rib fractures.

The use of seat belts in our series was reported in 47% of cases only. The diagnosis of sternal fractures is based on a history of chest trauma in patients wearing seat belts, presenting with pain and tenderness. Lateral sternal radiographs are of value to help confirm the diagnosis. However, these fractures could be easily missed.[2122] The most common associated injuries are rib fractures and cardiac injury.[9] In a study by Recinos et al.,[6] the incidence of sternal fractures was < 1% (0.33%) over a 10-year period, and 57% of patients experienced severe injuries with ISS > 16. This is contrast to older studies[14] that reported 50%–66% of their patients with an ISS ≤ 13. Our population had moderate to serious chest injuries, with a mean Abbreviated Injury Scale (AIS: 2.56 ± 0.6). Most traumatic sternal fractures occur in the context of polytrauma with isolated sternal fractures being rare. In this study, 56% of patients had rib fractures. Rib fractures can be a major cause of morbidity in patients with sternal fracture. This is aggravated in the presence of associated sternal and lung injuries and can progress into respiratory failure.[23] Contusion is reported to be present in 30%–75% of patients with significant blunt chest trauma.[24] Our analysis shows a 32.5% frequency of lung contusion, which is within the reported range. In a retrospective analysis of 1359 patients at a Level 1 trauma center, 16.7% of patients were found to have a pneumothorax with other studies reporting an incidence of approximately 18%.[25]

Several studies have examined the relationship of sternal fracture to blunt cardiac injury.[26] Sadaba et al.[27] evaluated 37 patients with isolated sternal fracture. They concluded that isolated sternal fracture is not a marker for blunt cardiac trauma (BCI), and these patients could be safely discharged if they had a normal chest radiograph and normal electrocardiogram (ECG) results. In a retrospective review of 100 patients, the incidence of BCI was 4% with 67 patients who had isolated sternal fractures diagnosed by ECG.[21] Another review of 50 patients with a diagnosis of sternal fracture showed that of the 30 patients with isolated sternal fracture, only one patient (3%) had a BCI.[28] The incidence of BCI in this study was 17.4%. Despite this low incidence, a high index of clinical suspicion is required, particularly if the pattern of injury is highly suggestive. In our study, troponin was positive in 35% of patients, and those with rib fractures were more likely to have a higher positivity rate (39.0% vs. 30.6%).

It has been reported that sternal fractures are often accompanied by vertebral fractures, specifically the thoracic vertebrae.[5] Similarly, there were 46 patients with vertebral fractures in our group, and these fractures were most commonly localized in the thoracic vertebrae (14.2%). A study of 200 sternal fractures had a 13% incidence of spinal fractures,[11] whereas another study by Athanassiadi et al. reported an incidence of 4%.[21] A study by Krinner et al. showed that of all patients with sternal fracture, 30.96% also suffered from a vertebral fracture. The vertebral fractures most frequently occurred in the thoracolumbar region and the second cervical vertebral body.[29] Major vascular injuries are less common compared to other thoracic injuries.

Our findings are clinically relevant and would help inform physicians caring for patients with sternal fractures. At physical examination, patients present with tenderness, swelling, crepitation, and deformity of the sternum. After the initial primary and secondary trauma survey, radiologic imaging should be performed for appropriate indications based on physical examination findings, mechanism of injury, and clinical suspicion. Portable chest radiography is the first-line imaging method used for the evaluation of polytrauma. However, CT is superior to chest radiography, as it can demonstrate significant lesions in cases with normal initial radiography.[3031]

The sternum usually fractures transversely, at the body or manubrium, and fractures may vary from a simple undisplaced to comminuted fractures with overlapping fragments.[9] Most fractures of the sternum involve the body, a fact noted in previous studies.[3233] The location of sternal fracture can be an indicator for serious associated injuries. However, many studies were not able to demonstrate this significant correlation.[1334] In our case, the sternum was primarily divided into four zones. The predominant fracture locations were in the middle sternum and the manubrium sterni (36% each). Fractures of the upper as well as lower part of the corpus sterni were seen in 20.2% and 14.5%, respectively. In a study by Scheyerer et al.,[35] the predominant fracture location was the manubrium sterni. They were associated more with thoracic spine and other chest injuries and a higher mean ISS. Furthermore, the incidence of head injuries and ICU admission was significantly higher. A total of 16.5% of sternal fractures were localized at the manubrium, mostly caused by seat belt.

Fractures without significant dislocation were stable and healed well by conservative treatment. Dislocated fractures caused instability of shoulder girdle and necessitated anterior plating to allow proper consolidation.[36] Isolated sternal fractures have an excellent prognosis with complete recovery within 10 weeks, with an overall mortality rate of 0.7%. However, surgical fixation is rarely needed.[15] Isolated sternal fracture is a mild injury that can usually be treated in outpatient settings to reduce complications and cost associated with hospitalization.[37] Therefore, these patients can be safely discharged after observation in a short stay unit.[38] The presence of additional injuries and a history of cardiac disease are alerting factors. These patients should be admitted for close monitoring.

We acknowledge several limitations of the present study. The retrospective design is a limitation. The study was undertaken at a single trauma center; this might have introduced selection bias and limited the external validity of the findings. Another limitation is the presence of associated injuries that make it difficult to find isolated sternal fractures. Anatomic features such as degree of displacement and location are not recorded properly and may affect outcome. ECG, cardiac enzyme testing, and echocardiographic findings were available in 23%, 62%, and 16%, respectively, in our data; however, cardiac monitoring should be initiated in all sternal injury patients who required admission.

CONCLUSIONS

Sternal fractures are rare, and detection of associated injuries requires a high index of suspicion. Combined sternal and rib fractures are more evident in relatively older patients after chest trauma. This combination has certain clinical implications that necessitate further prospective studies.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to require Institutional Review Board / Ethics Committee review, and appropriate approval was granted by the Medical Research Center at Hamad Medical Corporation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.