Suspected Nonaccidental Trauma and Femoral Shaft Fractures in Children

Abstract

The question of suspected nonaccidental trauma as a possible cause of injury for femoral shaft fractures in children is a troubling but common issue facing orthopedic surgeons. The purpose of this study is to analyze femoral shaft fractures at a major pediatric level I trauma center in a large metropolitan area over a 5-year period to determine the incidence of suspected nonaccidental trauma and the risk factors associated with that diagnosis. This study is a retrospective review of all children younger than 5 years at a large trauma center in a southwestern metropolitan area who presented with a femoral shaft fracture. Patient charts were reviewed to determine demographics, mechanism of injury, and fracture type. Referrals to social work and Child Protective Services were also reviewed to determine an overall incidence of suspected nonaccidental trauma.

Over the 5-year study period, 137 patients presented to our institution with a femoral shaft fracture. Mean patient age at the time of injury was 2.2 years (range, 1 month to 4 years). Overall, 43 patients with a mean age of 1.8 years were determined to have injuries suspicious of nonaccidental trauma and were referred to Child Protective Services, giving an overall incidence of 31%. Age younger than 1 year was a highly significant risk factor for suspected nonaccidental trauma. Of the 20 children younger than 1 year, 18 (90%) were referred to Child Protective Services, comprising 42% of those children suspicious of nonaccidental trauma. The presence of either Medicaid or no insurance was a highly statistically significant risk factor for suspected nonaccidental trauma.

Femoral shaft fractures in children are one of the most common major injuries that pediatric orthopedic surgeons manage. As orthopedists, we commonly evaluate and treat femur fractures in different age groups, with different fracture patterns and mechanisms of injury, and often with associated injuries.¹ Often, we are confronted with suspected nonaccidental trauma as a possible cause of injury.

Nonaccidental trauma, or child abuse, continues to be a significant cause of morbidity and mortality in children today.^2-4 Second only to burns and bruises, fractures are the second most common manifestation of nonaccidental trauma. Certain fracture patterns are considered more suggestive than others for nonaccidental trauma, including spiral humeral fractures, metaphyseal corner fractures of the distal femur and tibia, and others.⁵ Spiral fractures in general have been thought to have a high likelihood of nonaccidental trauma because of the typical “twisting” mechanism required to cause such a fracture. Therefore, spiral femur fractures have also been associated with nonaccidental trauma, but with less certainty than the other fractures discussed. Fractures of children younger than 1 year are highly associated with nonaccidental trauma, because infants do not have the mobility required to sustain accidental trauma with sufficient energy to cause a fracture.

Several studies have been performed investigating the association of nonaccidental trauma in femur fractures in children.^6-9 These studies have demonstrated that children younger than 1 year are at an increased risk of nonaccidental trauma, and that no 1 particular fracture type is typical of abuse. However, these previous studies have several limitations. Some of these series have relatively small numbers with limited power to detect accurately a trend with a relatively small magnitude, like the incidence of nonaccidental trauma.⁷ Also, many of the previous reports had their data derived from the late 1990s; the magnitude and characterizations of nonaccidental trauma may be different in 2009 in the United States.^7-9 Finally, some studies do not distinguish between femoral metaphyseal fractures (like corner fractures, which have a relatively high rate of nonaccidental trauma) and femoral shaft fractures, which may have a much lower incidence of abuse.^6,7

The purpose of this study is to retrospectively analyze a large series of femoral shaft fractures at a major pediatric level I trauma center in a large southwestern metropolitan service area over a recent 5-year period. Specifically, this study will determine the incidence of nonaccidental trauma in femoral shaft fractures in children and will determine the characterizations of that diagnosis by age, mechanism of injury, and fracture type.

Materials and Methods

All patients who presented with a femoral shaft fracture treated at our institution, a high-volume, metropolitan level-I trauma center, from 2003 to 2008 were identified. The hospital’s Institutional Review Board reviewed and approved the study. The patients were identified by a search of the hospital’s ICD9 and discharge diagnoses. Patients with pathological fractures (eg, osteogenesis imperfecta, fractures associated with osteomyelitis or bone tumors) were excluded from the analysis. Patients with proximal femur fractures (femoral neck, intertrochanteric, or subtrochanteric fractures) or distal femur fractures (including metaphyseal distal femur fractures, which are not frequently the result of abuse) were also excluded.

Data collected included patient age, sex, race/ethnicity, social history, insurance type, fracture type, mechanism of injury, relevant witnesses, associated injuries, treatment type, fixation type, complications, reoperations, length of stay, forensic evaluation, and Child Protective Services referral.

At our institution, if any physician has a suspicion of nonaccidental trauma, a formal consult to the forensic team is instituted. This involves a team comprising a physician, a nurse practitioner with special expertise in nonaccidental trauma, and a social worker. Child Protective Services referral may be made directly by the attending pediatric orthopedic surgeon or by the forensic team.

The ultimate, legal determination of whether the child’s injuries were sustained by nonaccidental trauma or by accidental trauma is ultimately determined by Child Protective Services. The final decision by Child Protective Services is protected data and usually not available in an analysis such as this. The responsibility of the pediatric orthopedic surgeon (in terms of the determination of whether a given injury is nonaccidental trauma) usually ends after referral of the case to Child Protective Services. Therefore, we used Child Protective Services referral as our primary endpoint. If Child Protective Services immediately dismissed the case as accidental trauma during the index hospitalization of the child, that case was excluded as a case of nonaccidental trauma.

Groups of fractures that occurred by nonaccidental trauma and by accidental trauma were then compared on the basis of age, mechanism of injury, fracture type, insurance status, and presence of associated injuries. Statistical comparisons were made by the use of chi-squared analysis, with a P value of .05 used to determine statistical significance.

Results

The study identified 137 patients with femoral shaft fractures in patients aged 5 years and younger during the time period of interest (2003-2008). Mean patient age was 2±2 years (range, 1 month to 4±11 years). One hundred boys (73%) and 37 girls (27%) were identified. Twenty patients were aged 1 year or younger (14%); the majority of fractures occurred in children older than 1 year (86%).

Seventy-one fractures were midshaft spiral fractures (52%), 42 were short oblique fractures (31%), 16 were transverse fractures (12%), and 8 were comminuted fractures (6%). The mechanism of injury was a fall in 90 patients (66%), twisting injury during play in 17 (12%), trampoline in 4 (3%), motor vehicle accident in 4 (3%), and unknown in 22 (16%).

Eighteen patients (13%) of the 137 presented with associated injuries. The types of injuries varied greatly, from small lacerations and abrasions to other fractures, including skull fractures. Sixty-eight patients (49%) were on Medicaid insurance plans, 58 (42%) were on commercial insurance plans, and 11 had no insurance (8%).

Of the 137 patients, 66 (48%) were referred to the forensics team by the attending pediatric orthopedic surgeon. Of those 66, forty-three (65%) were felt by forensics and/or the attending pediatric surgeon to be suspicious of nonaccidental trauma, and a Child Protective Services referral was made. Therefore, the overall rate of suspected nonaccidental trauma in this series was 31.3%.

Eighteen of the 43 patients (42%) referred to Child Protective Services were younger than 1 year. Eighteen of the 20 patients in the overall series younger than 1 year were referred to Child Protective Services (90%). Age was a highly significant risk factor for suspected nonaccidental trauma (P<.0001). However, 25 additional patients older than 1 year were felt to be suspicious for nonaccidental trauma, requiring a Child Protective Services referral and investigation, with a risk factor of 21% (Figure 1).

Figure 1: Effect of age on Child Protective Services (CPS) referral for femoral shaft fracture. Abbreviation: yo, year old.

Of those patients referred to Child Protective Services, 26 (60%) had spiral fractures, 12 (28%) had oblique fractures, 3 (7%) had transverse fractures, and 2 (5%) were comminuted. Fracture type was not a statistically significant risk factor for suspected nonaccidental trauma (P=.56) (Figure 2). Of those patients referred to Child Protective Services, the mechanism of injury was fall in 22 patients (51%), twisting injury during play in 3 (7%), motor vehicle accident in 1 (2%), and unknown in 17 (40%). An unknown mechanism of injury was a highly significant risk factor for suspected nonaccidental trauma (P<.0001) (Figure 3).

Figure 2: Effect of fracture type on Child Protective Services (CPS) referral. Abbreviation: NS, not significant.

Figure 3: Effect of mechanism of injury (MOI) on Child Protective Services (CPS) referral.

Of the 18 patients with associated injuries, a forensics consult was placed in 12 (67%). Child Protective Services referral was made in 9 cases (50%). Of the 43 patients referred to Child Protective Services, 9 (21%) had associated injuries. The presence of an associated injury was not a significant risk factor for suspected nonaccidental trauma (P=.186).

Twenty-eight of the 43 children referred to Child Protective Services were on Medicaid insurance plans (65%), 10 were on commercial plans (23%), and 5 had no insurance (12%). The presence of either Medicaid or no insurance was a highly statistically significant risk factor for suspected nonaccidental trauma (P=.008) (Figure 4).

Figure 4: Effect of insurance type on Child Protective Services (CPS) referral.

Discussion

Femoral shaft fractures in children are a common injury treated by pediatric orthopedic surgeons. Determining which of those patients is a possible victim of abuse requires careful analysis of the patient’s history, physical examination, and radiographs.^5,10 Unfortunately, the incidence of nonaccidental trauma in the pediatric population remains high and is a significant problem facing our society.^2-4 This study retrospectively analyzed a large series of femoral shaft fractures at a major pediatric level I trauma center in a large southwestern metropolitan service area over a recent 5-year period.

Several studies investigate the association of nonaccidental trauma in femur fractures in children. Hui et al⁶ found an incidence of nonaccidental trauma in 127 femur fractures in children younger than 3 years over an 11-year period to be 11%. Rex and Kay⁷ reported on a case series of 33 femur fractures in children occurring from nonaccidental trauma and compared that to a group of children with accidental femur fractures; 92% of the fractures from nonaccidental trauma were in children younger than 1 year. Scherl et al⁸ found that in a cohort of >200 pediatric femoral shaft fractures, other fracture types were just as prevalent in nonaccidental trauma as the spiral fracture. Finally, Schwend et al⁹ reported that unless the child was younger than 1 year or there were other signs suggestive of nonaccidental trauma, the likelihood of abuse was lower than previously reported.

Many findings of the current study are similar to those previously reported. In this study, the most highly significant risk factor for suspected nonaccidental trauma was age younger than 1 year. That finding corroborates the findings of many other studies.^6,7,11 This study also supports the findings of Scherl et al,⁸ in that fracture type was not a significant risk factor for suspected nonaccidental trauma. Despite dogma, the spiral femur fracture in children is not more highly associated with nonaccidental trauma than any other fracture type.

However, this study also demonstrates findings that were not previously reported. The presence of associated injuries (eg, cuts, bruises, abrasions, other fractures) has long been thought to be a significant risk factor for suspected nonaccidental trauma. This heightened awareness makes clinical sense; however, the data in this study showed that the presence of an associated injury was not a statistically significant risk factor for suspected nonaccidental trauma, although the P value suggests that there may be a positive trend and may be significant with a higher powered study. The lack of a specific mechanism of injury was a significant risk factor for suspected nonaccidental trauma, accounting for 40% of the cases referred to Child Protective Services.

It has been traditionally thought that child abuse crosses all socioeconomic boundaries, and data exist to support that.^2-5 However, the current study shows that if the patient was on Medicaid or had no insurance, the femur fracture had a statistically higher chance of being the result of nonaccidental trauma, compared to those patients with commercial insurance.

We used Child Protective Services referral as our primary endpoint for several reasons. First, the final determination of whether a child is a victim of nonaccidental trauma is many times not clearly delineated, even with a thorough Child Protective Services evaluation. Second, many of the Child Protective Services findings and the findings of subsequent legal proceedings are not readily available to the public, even to the medical team taking care of the child. Finally, we felt that the crucial responsibility of the orthopedic surgeon in the determination of suspected nonaccidental trauma was the referral to Child Protective Services. After that referral was made, the medical–legal burden of the pediatric orthopedic surgeon is completed.

Almost of all of the children younger than 1 year who presented to our institution with a femoral shaft fracture were referred to Child Protective Services (90%). That is much higher than in previous studies,⁹ which gave an overall incidence of nonaccidental trauma of 43% in children younger than 1 year. We attribute our higher referral rate to our institution’s adoption of the vigilance of suspicion of nonaccidental trauma suggested by previous studies.^6,8 Although most of our referrals were children younger than 1 year, 25 patients older than 1 year (21%) were felt to be at significant risk of nonaccidental trauma and warranted a Child Protective Services referral. We suggest that vigilance and suspicion remain high despite the age, and that nonaccidental trauma can occur in children older than 1 year.

The association of lower insurance status and the risk factor for nonaccidental trauma raises the question of the impact of socioeconomic status and child abuse. While it is well known that child abuse can occur across all levels of socioeconomic status, this study suggests that those children in households with no insurance or government-subsidized insurance are at increased risk for abuse. Other socioeconomic factors such as race, family makeup (presence of the mother, father, or extended family members), and mean annual income levels could also be investigated to determine their effects on nonaccidental trauma. We chose insurance status as an independent variable to minimize potential biases and prejudices that may come from other socioeconomic factors.

The development and maturation of the forensics team and process at our institution has greatly improved our ability to make proper referrals to Child Protective Services and to improve the care of these children.

Conclusion

A femur fracture occurring in a patient younger than 1 year is a significant risk factor for suspected nonaccidental trauma. The patient who is uninsured or has Medicaid insurance also has a higher risk of being the victim of nonaccidental trauma. However, the pediatric orthopedic surgeon should always carefully examine each patient as a possible victim of nonaccidental trauma and make referrals to Child Protective Services as necessary. 

References

1. Flynn JM, Schwend RM. Management of pediatric femoral shaft fractures. J Amer Acad Orthop Surg. 2004; 12(5):347-359.
2. Sedlak A, Broadhurst DD, eds. The Third National Incidence Study of Child Abuse and Neglect: Final Report. Washington, DC: US Department of Health and Human Services; 1996.
3. US Department of Health and Human Services, National Center on Child Abuse and Neglect. Child Maltreatment 1995: Reports From the States to the National Child Abuse and Neglect Data System. Washington, DC: US Government Printing Office; 1997.
4. Lung CT, Daro D, eds. Current Trends in Child Abuse Reporting and Fatalities: The Results of the 1995 Annual Fifty State Survey. Chicago, IL: National Committee to Prevent Child Abuse; 1996.
5. Kocher MS, Kasser JR. Orthopaedic aspects of child abuse. J Am Acad Orthop Surg. 2000; 8(1):10-20.
6. Hui C, Joughin E, Goldstein S, et al. Femoral fractures in children younger than three years: the role of nonaccidental injury. J Pediatr Orthop. 2008; 28(3):297-302.
7. Rex C, Kay PR. Features of femoral fractures in nonaccidental injury. J Pediatr Orthop. 2000; 20(3):411-413.
8. Scherl SA, Miller L, Lively N, Russinoff S, Sullivan CM, Tornetta P III. Accidental and nonaccidental femur fractures in children. Clin Orthop Relat Res. 2000; (376):96-105.
9. Schwend RM, Werth C, Johnston A. Femur shaft fractures in toddlers and young children: rarely from child abuse. J Pediatr Orthop. 2000; 20(4):475-481.
10. Akbarnia BA, Akbarnia NO. The role of the orthopedist in child abuse and neglect. Orthop Clin North Am. 1976; 7(3):733-742.
11. Arkader A, Friedman JE, Warner WC Jr, Wells L. Complete distal femoral metaphyseal fractures: a harbinger of child abuse before walking age. J Pediatr Orthop. 2007; 27(7):751-753.

Authors

Drs Shrader and Segal and Mr Bernat are from the Division of Pediatric Orthopedic Surgery, Phoenix Children’s Hospital, Phoenix, Arizona.

Drs Shrader and Segal and Mr Bernat have no relevant financial relationships to disclose.

Correspondence should be addressed to: M. Wade Shrader, MD, Division of Pediatric Orthopedic Surgery, Phoenix Children’s Hospital, 1919 E Thomas Rd, Phoenix, AZ 85016 (mwshrader@phoenixchildrens.com).

doi: 10.3928/01477447-20110317-06