Simultaneous Bilateral Femur Fractures in Children: A Case Series from a Pediatric Level I Trauma Center and Review of the Literature

Abstract

Background:

Bilateral femur fractures are rare in the pediatric population with few cases reported in the literature. The purpose of this study was to review our institutional experience with a case series of simultaneous bilateral femur fractures to highlight the presentation, treatment, and outcomes of these rare injuries as well as perform a preliminary comparison to similar unilateral femur fractures in order to identify any clinically relevant differences that may guide future management.

Methods:

We undertook a retrospective chart review of patients who had presented with simultaneous bilateral femur fractures between 2007 and 2017 with a minimum of 1-year of follow-up. Descriptive information was provided about the case series of bilateral femur fracture patients with subsequent further analysis comparing unilateral and bilateral femur fractures.

Results:

Eight patients (7 males, 1 female) were identified after chart review. Mean age at the time of injury was 11 years (8 to 15 years). Mechanism of injury was high energy trauma in 7 of 8 patients. Six of 8 patients presented with at least one significant associated injury. All patients underwent operative fixation bilaterally. Average length of stay was 12 days (range 4-27 days). Four patients required admission to inpatient rehab facility. Complete healing occurred in all patients. One patient experienced unilateral genu valgum deformity treated successfully with growth modulation. Another patient experienced a unilateral bony bar of approximately 20% of the physis which did not result in angular deformity or limb length discrepancy. After comparing to a matched unilateral femur fracture cohort, we found that patients who sustained bilateral femur fractures had a significantly higher number of associated injuries as well as greater length of stay (p<0.05). There was no statistical difference in complications.

Conclusions:

Our case series illustrates the presentations and outcomes of this rare injury pattern in children along with a few potential differences that distinguish bilateral femur fractures from unilateral fractures. These results may help guide healthcare personnel in making management decisions regarding this rare injury.

Level of Evidence: IV

Introduction

Pediatric femur fractures are relatively common injuries with an annual incidence of approximately 19 per 100,000.¹ Bilateral femur fractures are much less common, with an unknown incidence. In the pediatric population, these fractures occur in a bimodal distribution with most occurring at 2-3 years of age as well as 17-18 years of age.² Most femur fractures in children are typically caused by high energy trauma such as car accidents or falls, while low energy fractures are rare and usually due to genetic, metabolic, or endocrine disorders.³ The treatment for these fractures may include traction, cast immobilization, external fixation, or internal fixation using plate and screws or intramedullary nails.^4,5 Complications following unilateral femur fractures have been well described before and include wound infection, re-fracture, nonunion/ malunion, avascular necrosis, growth arrest, and limb-length discrepancy.^6-9 However, the management and complications following bilateral femur fractures have not been well examined.

The current literature on pediatric bilateral femur fractures is limited to sparse case reports. The purpose of this study was to review our institutional experience with a case series of simultaneous bilateral femur fractures and highlight the presentation, treatment, and outcomes of these rare injuries as well as perform a comparison to similar unilateral femur fractures in order to identify any clinically relevant differences that may guide future management. We hypothesized that simultaneous bilateral femur fractures would have initially greater severity at time of presentation due to higher energy trauma and also have worse outcomes and/or a higher incidence of complications.

Methods

A retrospective review of a prospectively collected institutional femur fracture database was conducted for patients aged 0-18 years who presented with bilateral femur fractures between 2007 and 2017. Institutional review board approval was obtained before performing this study. All patients had a minimum of 1-year follow up.

We performed a retrospective review of these patients. Data was collected which included demographics, mechanism of injury, fracture location, pattern, treatment modality, length of stay, physical therapy usage, return to activity, and short/long-term complications. Descriptive information was provided about the case series of bilateral femur fracture patients. Subsequent further analysis was conducted to compare unilateral and bilateral femur fractures in a 2:1 fashion. Unilateral femur fractures that met case matched criteria (identical age, gender, and fracture location) were identified from the same femur fracture database.

Descriptive statistics was performed to obtain frequencies and measures of central tendency (mean, median). All categorical data was initially analyzed using Pearson Chi-Squared test or Fisher’s Exact test for statistical significance. Continuous variables were analyzed using t-test or Mann-Whitney U test, if nonparametric. P<0.05 was considered significant for all statistical tests. Analyses were performed using SPSS (IBM Corp, Armonk, NY) statistical software.

Results

We identified 8 children with simultaneous bilateral femur fractures (Figure 1). The mean age at the time of injury was 10.8±2.7 years (range: 7-15 years). 7 of 8 patients were male. The mechanism of injury was high energy trauma in 7 of 8 patients, including five instances of pedestrians struck by a motor vehicle. One patient sustained bilateral femur fractures after a ground level fall in the setting of Duchenne Muscular Dystrophy and osteoporosis. Six patients had at least one significant associated injury, including four patients with traumatic brain injury (TBI), four patients with intra-abdominal injuries, and two patients with spinal fractures.

Figure 1.

Case series of bilateral femur fractures.

All injuries were closed. 12 out of 16 fractures involved the femoral shaft, three involved the distal femur physis, and one was intertrochanteric. All patients underwent operative fixation bilaterally. Method of fracture fixation varied according to patient age as well as fracture location and pattern. Treatment options included rigid/flexible Intramedullary Nail (IMN), Plate/Screw constructs, and Closed Reduction with Percutaneous Pinning (CRPP). Average length of stay was 12 days (range 4-27 days). Four patients required admission to inpatient rehab facility.

There were no mortalities in the perioperative period or at long term follow up. All fractures went on to union. There were no instances of infection or re-fracture. One patient experienced unilateral genu valgum deformity treated successfully with medial hemi-epiphysiodesis and plating. Another patient experienced a unilateral bony bar of approximately 20% of the physis which did not result in angular deformity or limb length discrepancy. Patients returned to full activity at an average of 5.8 months respectively (range 3-9 months).

One bilateral femur fracture case involving a patient with Duchenne’s muscular dystrophy was excluded from the following comparisons. Subsequent analysis was conducted comparing seven bilateral femur fracture cases to 16 unilateral femur fracture cases that were matched according to age, gender, and fracture location (Table 1). There were no statistically significant differences found between the bilateral and unilateral groups when comparing age and gender. The number of associated injuries at time of presentation was different, with the bilateral fractures cohort having a significantly greater number of associated injuries (p<0.05). Two patients required blood transfusion in the bilateral cohort, one of whom had sustained multiple abdominal injuries. No patients required blood transfusion in the unilateral cohort. Average length of stay in the bilateral group was 12.9 days compared to 4.5 days in the unilateral group, which was found to be statistically significant (p<0.05). The mean number of complications in the unilateral patient cohort was 0.5, compared to 0.7 in the bilateral cohort. The difference in complications between the two groups was not found to be significant (p>0.05). Average number of months required to return to activity was also not significantly different between the bilateral and unilateral groups (p>0.05).

Table 1.

Clinical Characteristics of Unilateral vs. Bilateral Femur Fractures

	Unilateral Cohort	Bilateral Cohort
Mean Age (years)	10.8	10.1
Gender
Males	14	6
Females	2	1
Mean Number of Associated Injuries	0.4	2.9
Mean Length of Stay	4.5 days	12.9 days
Mean Number of Complications	0.5	0.7

*This table excludes the Duchenne’s patient from the Bilateral cohort.

Discussion

Bilateral femur fractures in the pediatric population are rare injuries that have not been well described in the literature so far. Here we presented a case series of 8 such patients, the largest of its kind to our knowledge, along with complications and outcomes following minimum 1-year follow-up. Subsequent comparisons to similarly matched unilateral femur fractures were also made.

As one would expect, patients with bilateral femur fractures had a statistically significant greater number of associated injuries at time of presentation. These associated injuries included traumatic brain injuries, multiple fractures, and cardiothoracic/abdominal injuries. This is most likely attributed to the greater trauma/ force sustained in order to produce bilateral fractures in comparison to the force needed to produce a unilateral fracture. High impact pedestrian-motor vehicle accidents were the cause of injury for 6 out of 8 patients in our series. Length of stay was also found to be significantly greater in the bilateral group. Though the mean number of fracture related complications was different in the two groups, this was not found to be statistically significant.

Few cases of bilateral femur fractures have been reported in the literature. Most are related to high speed trauma. Scott et al.¹⁰ reported bilateral proximal femur fractures in a 4-year old following an ATV injury. The patient underwent bilateral open reduction and internal fixation which was complicated by left hip avascular necrosis. Smith reported a case of a 4-year old who presented with bilateral femoral shaft fractures after a high speed MVA. The patient was treated with flexible intramedullary nailing and had an uneventful recovery.¹¹ Conners and Ochsenschlager also reported a case of a 9-month old child who sustained bilateral femoral shaft fractures after a high-speed motor vehicle accident. The patient was managed with prolonged spica casting.¹² Dhar reported a case of a 9-year old girl who presented with bilateral femoral neck fractures following a motor vehicle accident. The patient was managed with early open reduction and internal fixation with a successful outcome.¹³ These reports are consistent with the results of our series, where we noted that most pediatric bilateral femur fractures are associated with high speed trauma, particularly pedestrian struck injuries.

Mortality after bilateral femoral fractures in the adult population ranges from 6-32%.^14-21 In the adult literature, deep vein thrombosis/pulmonary embolism, hemorrhage, and pneumonia have been reported as potential serious complications.²² Although we observed a high incidence of associated injuries in this series, we found no instances of mortality. It is well described that children have different physiologic response to trauma that is functionally and mechanistically different compared to adults.²³ Pediatric patients have decreased systemic inflammatory activation which may be protective against mortality in the polytrauma situation.^24,25

There are numerous limitations to this study. Despite being the largest series of patients with bilateral pediatric femur fractures, the sample size remains relatively small and is retrospective in nature. As a result, comparisons to the unilateral group would benefit from a larger cohort. In addition, this was a heterogeneous group of surgeons treating patients over a long period of time at a large, tertiary care hospital which may not be representative of the typical management of these injuries at other institutions. Other limitations include the reliability of analyzing a retrospective database- with results being dependent on the accuracy of medical record data collection and coding which are often subject to physician/other medical professional error and bias. Finally, longer term follow-up is necessary to accurately assess complications.

Conclusion

This report of 8 patients demonstrates that bilateral femur fractures in the pediatric population are commonly a result of high energy trauma and highlights the importance of careful preoperative evaluation. Although bilateral femur fractures may have worse initial presentation, greater length of stay, and more complicated multi-specialty management, once appropriately treated, their short term outcomes and complications are similar to their unilateral counterparts. We believe that with coordinated pediatric trauma care, successful management is possible as with the majority of patients in this series.