Chapter 1: Epidemiology of Fractures in Children

Brian Brighton, Michael Vitale

Chapter Outline

Introduction

Epidemiology is defined as the study of the distribution and determinants of health and disease and the application of this science to the control of diseases and other health problems. As such, epidemiology is the cornerstone of an evidence-based approach to preventing disease, and to optimizing treatment strategies. The term “epidemiology” is derived from the Greek roots epi = upon, demos = people, logos = study, meaning “the study of what is upon the people.” Although epidemiology was originally applied to communicable diseases, those who care for children will immediately understand that trauma is the disease that is “upon the people” under our care. Various epidemiologic methods including surveillance and descriptive studies can be used to investigate the distribution of frequency, pattern, and burden of disease whereas analytical methods can be used to study the determinants of disease. An understanding of the epidemiology of pediatric trauma is a prerequisite for the timely evolution of optimal care strategies, and for the development of effective prevention strategies. 
Injuries in children and adolescents represent a major public health challenge facing pediatric patients, families, and health care providers worldwide. The incidence of pediatric trauma in the United States is among the highest in the developing world, reflecting the realities of urban violence, firearms, and the dangers of a highly mechanized society. Given the wide-reaching impact that pediatric musculoskeletal injury has on public health, an understanding of the epidemiology of pediatric fractures provides an opportunity to maximize efforts aimed at prevention and optimal treatment. Unintentional injuries are the leading cause of death for children in the United States. In 2009, the Centers for Disease Control and Prevention (CDC) reported 7,712 deaths of children between the ages of 0 and 18 years caused by unintentional injuries (http://webappa.cdc.gov/sasweb/ncipc/mortrate10_us.html). However, fatalities only represent a small portion of the impact unintentional injuries have on children. There were 8,612,481 nonfatal unintentional injuries to children of the same age group in 2010. (http://webappa.cdc.gov/sasweb/ncipc/nfirates2001.html) Pediatric trauma often results in temporary activity limitation, hospitalization, and sometimes in permanent disability.2,63 Injuries requiring medical attention, or resulting in restricted activity, affect more than 20 million children and adolescents and cost $17 billion annually for medical treatment.33 As the leading cause of death and disability in children, pediatric trauma presents one of the largest challenges to the health of children, as well as an important opportunity for positive impact. 

Incidence of Fractures in Children

“Classification Bias”: Difficulties Defining Disease

Rigorous epidemiologic studies demand consistent information about how we define and classify a given disease state. This is a challenge in pediatric trauma, making it difficult to compare studies. Some studies extend the pediatric age group to only 16 years, for example, whereas others include patients up to 21 years of age. Moreover, it is particularly difficult to examine injuries that only sometimes result in admission. Many studies18,81 are limited to injuries that require hospital admission, despite the fact that most injuries in children do not. Reports vary in the precision of their defined types of fracture patterns. In the older series, reports were only of the long bone involved, such as the radius. Series that are more recent have emphasized a more specific location, separating the radius, for example, into physeal, distal, shaft, and proximal fracture types. Recently, an international study group has developed and attempted early validation of a standardized classification system of pediatric fractures.84,130133 The authors of an agreement study found that with appropriate training, the AO comprehensive pediatric long bone fracture classification system could be used by experienced surgeons as a reliable classification system for pediatric fractures for future prospective studies.130 
Thus, in trying to define the exact incidence of pediatric fractures, it is difficult to compare series because of cultural, environmental, and age differences. In the following synopsis, these differences were considered in grouping the results and producing average figures. These data are presented in an attempt to provide a reasonable and accurate reflection of the overall incidence of injuries and fractures in all children. It is estimated that the incidence of nonfatal injuries in children is 25% annually representing 56,000 injuries per day in the United States with an estimated 38 fatal injuries per 100,000 children.33,119 Fractures account for 8.5% to 25% of those injuries.71,128,147 
Early studies on the incidence of fractures in children formed a knowledge base about fracture healing in children. In 1941, Beekman and Sullivan11 published an extensive review of the incidence of children's fractures. Their pioneering work—still quoted today—included a study of 2,094 long-bone fractures seen over a 10-year period at Bellevue Hospital in New York City. The major purpose of their study was to develop basic principles for treating children's fractures. 
In 1954, two reports, one by Hanlon and Estes49 and the other by Lichtenberg,77 confirmed the findings of the previous studies with regard to the general incidence of children's long bone fractures and their ability to heal and readily remodel. These initial reviews were mainly statistical analyses and did not delve deeply into the true epidemiology of children's fractures. In 1965, Wong155 explored the effect of cultural factors on the incidence of fractures by comparing Indian, Malay, and Swedish children. In the 1970s, two other studies, one by Iqbal56 and another by Reed,110 added more statistics regarding the incidence of the various long bone fractures. 
Landin's 1983 report on 8,682 fractures remains a landmark study on the incidence of fractures in children.70 He reviewed the data on all fractures in children that occurred in Malmo, Sweden, over 30 years and examined the factors affecting the incidence of children's fractures. By studying two populations, 30 years apart, he determined that fracture patterns were changing and suggested reasons for such changes. His initial goal was to establish data for preventive programs, so he focused on fractures that produced clean, concise, concrete data. In 1997, Landin71 updated his work, reemphasizing the statistics from his previous publication. He suggested that the twofold increase in fracture rate during the 30 years from 1950 to 1979 in Malmo was caused mainly by an increased participation in sports. In 1999, in cooperation with Tiderius and Duppe, Landin studied the incidence in the same age group again in Malmo and found that the rate had actually declined by 9% in 1993 and 1994.144 The only exception was an increase of distal forearm fractures in girls, which he attributed to their increased participation in sporting events. The authors attributed this to less physical activity on the part of modern-day children coupled with better protective sports equipment and increased traffic safety (e.g., stronger cars and use of auto restraint systems). 
Cheng and Shen,26 in their 1993 study from Hong Kong, also set out to define children's fractures by separating the incidences into age groups. They tried to gather epidemiologic data to build preventive programs. In 1999, this study was expanded to include almost 6,500 fractures in children 16 and younger over a 10-year period.25 The fracture patterns changed little over those 10 years; however, there was an increased frequency of closed reduction and percutaneous pin fixation of fractures, with a corresponding decrease in open reductions along with a marked decrease in the hospital stay of their patients. 
More recently, studies on the incidence of fractures in Edinburgh, Scotland in 2000, as reviewed by Rennie et al.,111 was 20.2 per 1,000 children annually. A similar fracture incidence of 201/10,000 among children and adolescents was reported in northern Sweden between 1993 and 2007 with a 13% increase during the years between 1998 and 2007. The authors also reported the accumulated risk of sustaining a fracture before the age of 17 being 34%.52 In Landin's series from Malmo, Sweden, the chance of a child sustaining a fracture during childhood (birth to age 16) was 42% for boys and 27% for girls.70 When considered on an annual basis, 2.1% of all the children (2.6% for boys; 1.7% for girls) sustained at least one fracture each year. These figures were for all fracture types and included those treated on an inpatient basis and an outpatient basis. The overall chance of fracture per year was 1.6% for both girls and boys in a study from England of both outpatients and inpatients by Worlock and Stower.157 The chance of a child sustaining a fracture severe enough to require inpatient treatment during the first 16 years of life is 6.8%.26 Thus, on an annual basis, 0.43% of the children in an average community will be admitted for a fracture-related problem during the year. The overall incidence of children's fractures is summarized in Table 1-1
 
Table 1-1
Overall Frequency of Fractures
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Table 1-1
Overall Frequency of Fractures
Percentage of children sustaining at least one fracture from 0—16 y of age: Boys, 42%; girls, 27%
Percentage of children sustaining a fracture in 1 y: 1.6—2.1%
Percentage of patients with injuries (all types) who have fractures: 17.8%
 

From: Barlow B, Niemirska M, Gandhi RP, et al. Ten years of experience with falls from a height in children. J Pediatr Surg. 1983; 18(4):509–511; Hindmarsh J, Melin G, Melin KA. Accidents in childhood. Acta Chir Scand. 1946; 94(6):493–514; Iqbal QM. Long bone fractures among children in Malaysia. Int Surg. 1974; 59(8):410–415; Landin LA. Epidemiology of children's fractures. J Pediatr Orthop B. 1997; 6(2):79–83; Landin L, Nilsson BE. Bone mineral content in children with fractures. Clin Orthop Relat Res. 1983;(178):292–296; Nathorst Westfelt JA. Environmental factors in childhood accidents: A prospective study in Goteborg, Sweden. Acta Paediatr Scand Suppl. 1982; 291:1–75; Stark AD, Bennet GC, Stone DH, et al. Association between childhood fractures and poverty: Population based study. BMJ. 2002; 324(7335):457; Laffoy M. Childhood accidents at home. Ir Med J. 1997; 90(1):26–27; Reed MH. Fractures and dislocations of the extremities in children. J Trauma. 1977; 17(5):351–354.

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Early reports of children's fractures lumped the areas fractured together, and fractures were reported only as to the long bone involved (e.g., radius, humerus, femur).11,49,56,77,81 More recent reports have split fractures into the more specific areas of the long bone involved (e.g., the distal radius, the radial neck, the supracondylar area of the humerus).26,56,70,110,157 
In children, fractures in the upper extremity are much more common than those in the lower extremity.49,56 Overall, the radius is the most commonly fractured long bone, followed by the humerus. In the lower extremity, the tibia is more commonly fractured than the femur (Table 1-2). 
 
Table 1-2
Incidence of Fractures in Long Bones
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Table 1-2
Incidence of Fractures in Long Bones
Bone %
Radius 45.1
Humerus 18.4
Tibia 15.1
Clavicle 13.8
Femur 7.6
 

From: Kempe CH, Silverman FN, Steele BF, et al. The battered-child syndrome. JAMA. 1962; 181:17–24; Rivara FP, Bergman AB, LoGerfo JP, et al. Epidemiology of childhood injuries. II. Sex differences in injury rates. Am J Dis Child. 1982; 136(6):502–506; Fleming DM, Charlton JR. Morbidity and healthcare utilisation of children in households with one adult: Comparative observational study. BMJ. 1998; 316(7144):1572–1576; Laffoy M. Childhood accidents at home. Ir Med J. 1997; 90(1):26–27; Lichtenberg RP. A study of 2,532 fractures in children. Am J Surg. 1954; 87(3):330–338; Rohl L. On fractures through the radial condyle of the humerus in children. Acta Chir Scand. 1952; 104(1):74–80.

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Given the fact that different reports classify fractures somewhat differently, it is somewhat of a challenge to distill detailed and accurate prevalence data for specific fractures; in trying to do so, we have identified areas common to a number of recent reports,26,56,70,110,157 but have taken some liberties in doing so. For example, distal radial metaphyseal and physeal fractures were combined as the distal radial fractures. Likewise, the carpals, metacarpals, and phalanges were combined to form the region of the hand and wrist. All the fractures around the elbow, from those of the radial neck to supracondylar fractures, were grouped as elbow fractures. This grouping allows comparison of the regional incidence of specific fracture types in children (Table 1-3). 
 
Table 1-3
Incidence of Specific Fracture Types
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Table 1-3
Incidence of Specific Fracture Types
Fracture %
Distal radius and physis 23.3
Hand (carpals, metacarpals, and phalanges) 20.1
Elbow area (distal humerus and proximal radius and ulna) 12
Clavicle 6.4
Radius shaft 6.4
Tibia shaft 6.2
Foot (metatarsals and phalanges) 5.9
Ankle (distal tibia) 4.4
Femur (neck and shaft) 2.3
Humerus (proximal and shaft) 1.4
Other 11.6
 

From: Barlow B, Niemirska M, Gandhi RP, et al. Ten years of experience with falls from a height in children. J Pediatr Surg. 1983; 18(4):509–511; Hindmarsh J, Melin G, Melin KA. Accidents in childhood. Acta Chir Scand. 1946; 94(6):493–514; Landin LA. Epidemiology of children's fractures. J Pediatr Orthop B. 1997; 6(2):79–83; Wareham K, Johansen A, Stone MD, et al. Seasonal variation in the incidence of wrist and forearm fractures, and its consequences. Injury. 2003; 34(3):219–222; Fleming DM, Charlton JR. Morbidity and healthcare utilisation of children in households with one adult: Comparative observational study. BMJ. 1998; 316(7144):1572–1576.

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The individual reports agreed that the most common area fractured was the distal radius. The next most common area, however, varied from the hand in Landin's series to the elbow (mainly supracondylar fractures) in Cheng and Shen's data (Fig. 1-1).26 
Figure 1-1
The frequency of occurrence of the most common fracture areas in children.
 
The frequency of each fracture pattern differs with the various age groups. The figures express the percentage of total fractures for that age group and represent boys and girls combined.
 
(Reprinted from Cheng JC, Shen WY. Limb fracture pattern in different pediatric age groups: A study of 3,350 children. J Orthop Trauma. 1993; 7(1):15–22, with permission.)
The frequency of each fracture pattern differs with the various age groups. The figures express the percentage of total fractures for that age group and represent boys and girls combined.
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Figure 1-1
The frequency of occurrence of the most common fracture areas in children.
The frequency of each fracture pattern differs with the various age groups. The figures express the percentage of total fractures for that age group and represent boys and girls combined.
(Reprinted from Cheng JC, Shen WY. Limb fracture pattern in different pediatric age groups: A study of 3,350 children. J Orthop Trauma. 1993; 7(1):15–22, with permission.)
The frequency of each fracture pattern differs with the various age groups. The figures express the percentage of total fractures for that age group and represent boys and girls combined.
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Physeal Fractures

The incidence of physeal injuries overall varied from 14.5%30 to a high of 27.6%.89 To obtain an overall incidence of physeal fractures, six reports totaling 6,479 fractures in children were combined.13,30,89,94,110,157 In this group, 1,404 involved the physis, producing an average overall incidence of 21.7% for physeal fractures (Table 1-4). 
 
Table 1-4
Incidence of Physeal Fractures
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Table 1-4
Incidence of Physeal Fractures
Total fractures = 6,477
Number of physeal injuries = 1,404
Percentage of physeal injuries = 21.7%
 

From: Barlow B, Niemirska M, Gandhi RP, et al. Ten years of experience with falls from a height in children. J Pediatr Surg. 1983; 18(4):509–511; Kowal-Vern A, Paxton TP, Ros SP, et al. Fractures in the under-3-year-old age cohort. Clin Pediatr (Phila). 1992; 31(11):653–659; Wong PCN. A comparative epidemiologic study of fractures among Indian, Malay and Swedish children. Med J Malaya. 1965; 20(2):132–143; Rohl L. On fractures through the radial condyle of the humerus in children. Acta Chir Scand. 1952; 104(1):74–80; Tiderius CJ, Landin L, Duppe H. Decreasing incidence of fractures in children: An epidemiological analysis of 1,673 fractures in Malmo, Sweden, 1993-1994. Acta Orthop Scand. 1999; 70(6):622–626.

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Open Fractures

The overall incidence of open fractures in children is consistent. The data were combined from the four reports in which the incidence of open fractures was reported.26,49,89,157 The incidence in these reports varied from 1.5% to 2.6%. Combined, these reports represented a total of 8,367 fractures with 246 open fractures, resulting in an average incidence of 2.9% (Table 1-5). 
 
Table 1-5
Incidence of Open Fractures
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Table 1-5
Incidence of Open Fractures
Total number of fractures = 8,367
Total open fractures = 246
Percentage = 2.9%
 

From: Barlow B, Niemirska M, Gandhi RP, et al. Ten years of experience with falls from a height in children. J Pediatr Surg. 1983; 18(4):509–511; Kowal-Vern A, Paxton TP, Ros SP, et al. Fractures in the under-3-year-old age cohort. Clin Pediatr (Phila). 1992; 31(11):653–659; Wong PCN. A comparative epidemiologic study of fractures among Indian, Malay and Swedish children. Med J Malaya. 1965; 20(2):132–143; Laffoy M. Childhood accidents at home. Ir Med J. 1997; 90(1):26–27.

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Regional trauma centers often see patients exposed to more severe trauma, so there may be a higher incidence of open fractures in these patients. The incidence of open fractures was 9% in a report of patients admitted to the trauma center of the Children's National Medical Center, Washington, DC.18 

Multiple Fractures

Multiple fractures in children are uncommon: The incidence ranges in the various series from 1.7% to as much as 9.7%. In four major reports totaling 5,262 patients, 192 patients had more than one fracture (Table 1-6).26,49,56,157 The incidence in these multiple series was 3.6%. 
 
Table 1-6
Incidence of Multiple Fractures
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Table 1-6
Incidence of Multiple Fractures
Total fractures = 5,262
Total number of multiple fractures = 192
Percentage = 3.6%
 

From: Barlow B, Niemirska M, Gandhi RP, et al. Ten years of experience with falls from a height in children. J Pediatr Surg. 1983; 18(4):509–511; Landin LA. Epidemiology of children's fractures. J Pediatr Orthop B. 1997; 6(2):79–83; Fleming DM, Charlton JR. Morbidity and healthcare utilisation of children in households with one adult: Comparative observational study. BMJ. 1998; 316(7144):1572–1576; Laffoy M. Childhood accidents at home. Ir Med J. 1997; 90(1):26–27.

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Fractures in Weak Bone

Children with generalized bone dysplasias and metabolic diseases that produce osteopenia (such as osteogenesis imperfecta) are expected to have recurrent fractures. In these patients, the etiology is understandable and predictable. However, some children with normal osseous structures are prone to recurrent fractures for reasons that remain unclear. The incidence of recurrent fractures in children is about 1%.36 
Landin and Nilsson69 found that children who sustained fractures with relatively little trauma had a lower mineral content in their forearms, but they could not correlate this finding with subsequent fractures. Thus, in children who seem to be structurally normal, there does not appear to be a physical reason for their recurrent fractures. 

Repeat Fractures

Failure to find a physical cause for repeat fractures shifts the focus to a psychological or social cause. The one common factor in accident repeaters has been a high incidence of dysfunctional families.58 In Sweden, researches found that children who were accident repeaters came from “socially handicapped” families (i.e., those on public assistance or those with a caregiver who was an alcoholic).101 Thus, repeat fractures are probably more because of behavioral or social causes than physical causes. Landin,71 in his follow-up article, followed children with repeat fractures (four or more) into adolescence and adulthood. He found these children had a significantly increased incidence of convictions for serious criminal offenses when compared with children with only one lifetime fracture. 
Despite the importance of understanding the epidemiology of pediatric fractures, there are still significant gaps in our knowledge base, and there is much work to be done. There are several challenges to gathering appropriate data in this area: risk factors for pediatric injury are diverse and heterogenous, practice patterns vary across countries and even within countries, and the available infrastructure to support data collection for pediatric trauma is far from ideal. 

Patient Factors Influence Fracture Incidence and Fracture Patterns

Age

Fracture incidence in children increases with age. Age-specific fracture patterns and locations are influenced by many factors including age-dependent activities and changing intrinsic bone properties. Starting with birth and extending to age 12, all the major series that segregated patients by age have demonstrated a linear increase in the annual incidence of fractures with age (Fig. 1-2).16,25,26,56,70,111,157 
Figure 1-2
Incidence of fractures by age.
 
Boys (◆)peak at 13 years whereas girls (■) peak earlier, at 12 years, and then decline.
 
(Reprinted from Rennie L, Court-Brown CM, Mok JY, et al. The epidemiology of fractures in children. Injury. 2007; 38(8):913–922, with permission.)
Boys (◆)peak at 13 years whereas girls (■) peak earlier, at 12 years, and then decline.
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Figure 1-2
Incidence of fractures by age.
Boys (◆)peak at 13 years whereas girls (■) peak earlier, at 12 years, and then decline.
(Reprinted from Rennie L, Court-Brown CM, Mok JY, et al. The epidemiology of fractures in children. Injury. 2007; 38(8):913–922, with permission.)
Boys (◆)peak at 13 years whereas girls (■) peak earlier, at 12 years, and then decline.
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Although there is a high incidence of injuries in children of ages 1 to 2, the incidence of fractures is low with most fractures being related to accidental or nonaccidental trauma from others.67 The anatomic areas most often fractured seem to be the same in the major series, but these rates change with age. Rennie et al.111 demonstrated in their 2000 study from Edinburgh that the incidence of fractures increased and fracture patterns changed as children aged. Fracture incidence curves for each of the most commonest fractures separated by gender were shown on six basic incidence curves similar to Landin's initial work (Fig. 1-3).70 When Landin compared these variability patterns with the common etiologies, he found some correlation. For example, late-peak fractures (distal forearm, phalanges, proximal humerus) were closely correlated with sports and equipment etiologies. Bimodal pattern fractures (clavicle, femur, radioulnar, diaphyses) showed an early increase from lower energy trauma, then a late peak in incidence caused by injury from high- or moderate-energy trauma likely caused by motor vehicle accidents (MVAs), recreational activities, and contact sports in the adolescent population. Early peak fractures (supracondylar humeral fractures are a classic example) were mainly caused by falls from high levels. 
Figure 1-3
Patterns of fracture: Variations with age.
 
The peak ages for the various fracture types occur in one of six patterns.
 
(Reprinted from Rennie L, Court-Brown CM, Mok JY, et al. The epidemiology of fractures in children. Injury. 2007; 38(8):913–922, with permission.)
The peak ages for the various fracture types occur in one of six patterns.
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Figure 1-3
Patterns of fracture: Variations with age.
The peak ages for the various fracture types occur in one of six patterns.
(Reprinted from Rennie L, Court-Brown CM, Mok JY, et al. The epidemiology of fractures in children. Injury. 2007; 38(8):913–922, with permission.)
The peak ages for the various fracture types occur in one of six patterns.
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Prematurity may also have some impact on the incidence of fractures in the very young child. Fractures not related to birth trauma reportedly occur in 1% to 2% of low–birth-weight or premature infants during their stay in a neonatal intensive care unit.7 A combination of clinical history, radiographic appearance, and laboratory data has shown evidence of bone loss from inadequate calcium and phosphorus intake in these infants. Correcting the metabolic status of these low–birth-weight infants, with special emphasis on calcium and phosphorus intake, appears to decrease the incidence of repeat fractures and to improve the radiographic appearance of their bony tissues. Once the metabolic abnormalities are corrected, this temporary deficiency seems to have no long-term effects. When premature infants were followed into later years, there was no difference in their fracture rate compared with that of children of normal birth weight.32 

Gender

Gender differences can be seen across the incidence of injures, location of injuries, and etiology of injuries across all age groups. For all age groups, the overall ratio of boys to girls who sustain a single fracture is 2.7:1.26 In girls, fracture incidence peaks just before adolescence and then decreases during adolescence.26,70,110 In the 10-year study from Hong Kong by Cheng et al.,25 the male incidence in the 12- to 16-year age group was 83%. The incidence of fractures in girls steadily declined from their peak in the birth to 3-year age group. 
In some areas, there is little difference in the incidence of fractures between boys and girls. For example, during the first 2 years of life, the overall incidence of injuries and fractures in both genders is nearly equal. During these first 2 years, the injury rates for foreign body ingestion, poisons, and burns have no significant gender differences. With activities in which there is a male difference in participation, such as with sports equipment and bicycles, there is a marked increase in the incidence of injuries in boys.25,112 The injury incidence may not be caused by the rate of exposure alone; behavior may be a major factor.146 For example, one study found that the incidence of auto/pedestrian childhood injuries peaks in both sexes at ages 5 to 8.116 When the total number of street crossings per day was studied, both sexes did so equally. Despite this equal exposure, boys had a higher number of injuries. Thus, the difference in the rate between the sexes begins to develop a male predominance when behaviors change. The difference in the injury rate between the genders may change in the future as more girls participate in activities with increased physical risk.25,112,144 

Hand Dominance

In most series, the left upper extremity demonstrates a slight but significant predominance.14,31,32,35,40,45 The ratio of left to right overall averages 1.3:1. In some fractures, however, especially those of supracondylar bones, lateral condyles, and the distal radius, the incidence is far greater, increasing to as much as 2.3:1 for the lateral condyle. In the lower extremity, the incidence of injury on the right side is slightly increased.49,70 
The reasons for the predominance of the left upper extremity have been studied, but no definite answers have been found. Rohl114 speculated that the right upper extremity is often being used actively during the injury, so the left assumes the role of protection. In a study examining the left-sided predominance in the upper extremity, Mortensson and Thonell96 questioned patients and their parents on arrival to the emergency department about which arm was used for protection and the position of the fractured extremity at the time of the accident. They found two trends: Regardless of handedness, the left arm was used more often to break the fall, and when exposed to trauma, the left arm was more likely to be fractured. 

Socioeconomic and Cultural Differences

The incidence of pediatric fracture varies in different cultural settings. For instance, Cheng and Shen26 studied children in Hong Kong who lived in confined high-rise apartments. Their risk of exposure to injury differed from the study by Reed110 of children living in the rural environment of Winnipeg, Canada. Two separate reviews by Laffoy67 and Westfelt101 found that children in a poor social environment (as defined by a lower social class or by dependence on public assistance) had more frequent accidents than more affluent children. In England, children from single-parent families were found to have higher accident and infection rates than children from two-parent families.42 In the United States, the increased rate of pediatric femur fractures was influenced by adverse socioeconomic and sociodemographic fractures.55 
Two additional studies in the United Kingdom looked at the relationship of affluence to the incidence of fractures in children. Lyons et al.85 found no difference in the fracture rates of children in affluent population groups compared to those of children in nonaffluent families. On the other hand, Stark et al.138 in Scotland found that the fracture rates in children from nonaffluent social groups was significantly higher than those in affluent families. 

Clinical Factors

In recent years there has been an attention to a number of clinically related factors in determining children's fractures, such as obesity, low bone mineral density, and low calcium and vitamin D intake. Obesity is an increasing health problem in children and adolescents representing a complex interaction of host factors, and is the most prevalent nutritional problem for children in the United States. In a retrospective chart review, Taylor et al.142 noted that overweight children had a higher reported incidence of fractures and musculoskeletal complaints. Although Leonard et al.75 found increased bone mineral density in obese adolescents, the lack of physical activity often seen in obesity may in fact lead to reduced muscle mass, strength and coordination resulted in impaired proprioception, balance and increased risk of falling and fracture. In a recent study, Valerio et al.147 confirmed a greater prevalence of overweight/obesity in children and adolescents with a recent fracture when compared to age- and gender-matched fracture-free children, and found obesity rate was increased in girls with upper limb fractures and girls and boys with lower limb fractures. 
Low bone mineral density and decreased bone mass are linked to increased fracture risk in the adult population; however, in children the relationship is less clear with a meta-analysis showing some association between fracture risk and low bone mineral density.29 In 2006, Clark examined in a prospective fashion the association between bone mass and fracture risk in childhood. Over 6,000 children, at 9.9 years of age were followed for 2 years and the study showed an 89% increased risk of fracture per SD decrease in size-adjusted bone mineral density.27 In a follow-up study of this same cohort the risk of fracture following slight or moderate-to-severe trauma was inversely related to bone size relative to body size perhaps reflecting the determinants of volumetric BMD such as cortical thickness on skeletal fragility.28 
Nutritional factors may also play a role in the incidence of fractures in children. In a study in Spain, a significant difference in fracture rates was found when cities with a higher calcium content in their water were compared with those with a lower calcium content. With all other factors being equal (e.g., fluoride content, socioeconomic background), children who lived in the cities with a lower calcium content had a higher fracture rate.148 An increase in the consumption of carbonated beverages has also been shown to produce an increased incidence of fractures in adolescents.158 

Environmental Factors Impact on Fractures in Children

Seasonal and Climatic Differences

Fractures are more common during the summer, when children are out of school and exposed to more vigorous physical activities (Fig. 1-4). An analysis of seasonal variation in many studies shows an increase in fractures in the warmer months of the years.25,26,52,70,111,114,151,157 The most consistent climatic factor appears to be the number of hours of sunshine. Masterson et al.,90 in a study from Ireland, found a strong positive correlation between monthly sunshine hours and monthly fracture admissions. There was also a weak negative correlation with monthly rainfall. Overall, the average number of fractures in the summer was 2.5 times than that in the winter. In days with more sunshine hours than average, the average fracture admission rate was 2.31 per day; on days with fewer sunshine hours than average, the admission rate was 1.07 per day. 
Figure 1-4
Distribution of children's fractures on a monthly basis.
 
Note the general increase from May to October.
 
(Reprinted from Reed MH. Fractures and dislocations of the extremities in children. J Trauma. 1977; 17(5):351–354, with permission.)
Note the general increase from May to October.
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Figure 1-4
Distribution of children's fractures on a monthly basis.
Note the general increase from May to October.
(Reprinted from Reed MH. Fractures and dislocations of the extremities in children. J Trauma. 1977; 17(5):351–354, with permission.)
Note the general increase from May to October.
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In Sweden, the incidence of fractures in the summer had a bimodal pattern that seemed to be influenced by cultural traditions. In two large series of both accidents and fractures in Sweden by Westfelt101 and Landin,70 the researchers noticed increases in May and September and significant decreases in June, July, and August. Both writers attributed this to the fact that those children in their region left the cities to spend the summer in the countryside. Thus, the decrease in the overall fracture rate was probably because of a decrease in the number of children at risk remaining in the city. 
Masterson et al.90 speculated that because the rate of growth increases during the summer, the number of physeal fractures should also increase, as the physes would be weaker during this time. For example, the incidence of slipped capital femoral epiphysis, which is related to physeal weakness, increases during the summer.8 However, Landin, in his study of more than 8,000 fractures of all types, found that the overall seasonal incidence of physeal injuries to be exactly the same as nonphyseal injuries.70 Thus, it appears that climate, especially in areas where there are definite seasonal variations, influences the incidence of fractures in all children, especially in older children. However, in small children and infants, whose activities are not seasonally dependent, there appears to be no significant seasonal influence. 
The climate may be a strong factor as well. Children in colder climates, with ice and snow, are exposed to risks different from those of children living in warmer climates. The exposure time to outdoor activities may be greater for children who live in warmer climates. Pediatric trauma should be viewed as a disease where there are direct and predictable relationships between exposure and incidence. 

Time of Day

The time of day in which children are most active seems to correlate with the peak time for fracture occurrence. In Sweden, the incidence peaked between 2 pm and 3 pm.101 In a well-documented study from Texas by Shank et al.,124 the hourly incidence of fractures formed a well-defined bell curve peaking at about 6 pm (Fig. 1-5). 
Figure 1-5
Incidence of children's fractures per time of day.
 
There is an almost bell-shaped curve with a peak at around 6 pm.
 
(Reprinted from Shank LP, Bagg RJ, Wagnon J. Etiology of pediatric fractures: The fatigue factors in children's fractures. Paper presented at: Proceedings of the 4th National Conference on Pediatric Trauma; September 24–26, 1992; Indianapolis, IN, with permission.)
There is an almost bell-shaped curve with a peak at around 6 pm.
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Figure 1-5
Incidence of children's fractures per time of day.
There is an almost bell-shaped curve with a peak at around 6 pm.
(Reprinted from Shank LP, Bagg RJ, Wagnon J. Etiology of pediatric fractures: The fatigue factors in children's fractures. Paper presented at: Proceedings of the 4th National Conference on Pediatric Trauma; September 24–26, 1992; Indianapolis, IN, with permission.)
There is an almost bell-shaped curve with a peak at around 6 pm.
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Home Environment

Fractures sustained in the home environment are defined as those that occur in the house and surrounding vicinity. These generally occur in a fairly supervised environment and are mainly caused by falls from furniture, stairs, fences, and trees as well as from injuries sustained from recreational equipment (trampolines and home jungle gyms). Falls can vary in severity from a simple fall while running to a fall of great magnitude, such as from a third story window. In falling from heights, adults often land on their lower extremities, accounting for the high number of lower extremity fractures, especially the calcaneus. Children tend to fall head first, using the upper extremities to break the fall. This accounts for the larger number of skull and radial fractures in children. Femoral fractures also are common in children falling from great heights. In contrast to adults, spinal fractures are rare in children who fall from great heights.10,91,129,136 In one study, children falling three stories or less all survived. Falls from the fifth or sixth floor resulted in a 50% mortality rate.10 
Interestingly, a Swedish study101 showed that an increased incidence of fractures in a home environment did not necessarily correlate with the physical attributes or poor safety precautions of the house. Rather, it appears that a disruption of the family structure and presence of social handicaps (alcoholism, welfare recipients, etc.) is an important risk factor for pediatric fracture. 

School Environment

The supervised environments at school are generally safe, and the overall annual rate of injury (total percentage of children injured in a single year) in the school environment ranges from 2.8% to 16.5%.15,74,101,126 Most injuries occur as a result of use of playground or recreational equipment or participation in athletic activity. True rates may be higher because of inaccurate reporting, especially of mild injuries. In one series, the official rate was 5.6%, but when the parents were closely questioned, the incidence of unreported, trivial injuries was as much as 15%.40 In 2001 to 2002, a review of the National Electronic Injury Surveillance System (NEISS) demonstrated that 16.5% of the nearly 15 million injuries resulting in ED visits in school-aged children occurred at school.79 The annual fracture rate of school injuries is thought to be low. Of all injuries sustained by children at school in a year, only 5% to 10% involved fractures.40,74,126 In Worlock and Stower's series of children's fractures from England,157 only 20% occurred at school. Most injuries (53%) occurring in school are related to athletics and sporting events,74 and injuries are highest in the middle school children with one study citing a 20% fracture rate in school-aged children of those injured during physical education class.102 The peak time of day for injuries at school is in the morning, which differs from the injury patterns of children in general.42,74 

Etiology of Fractures in Children

Three Broad Causes

Broadly, fractures have three main causes: (i) Accidental trauma, (ii) nonaccidental trauma (child abuse), and (iii) pathologic conditions. Accidental trauma forms the largest etiologic group and can occur in a variety of settings, some often overlapping others. Nonaccidental trauma and fractures resulting from pathologic conditions are discussed in later chapters of this book. 

Sports-related Activities

The last two decades have seen an increase in youth participation in organized athletic participation, especially among younger children. Injuries in this population can occur in team or individual, organized or nonorganized, and contact and noncontact sporting activities. Wood et al. studied at the annual incidence of sports-related fractures in children 10 to 19 years presenting to hospitals in Edinburgh. The overall incidence was 5.63/1,000/year with males accounting for 87% of fractures. Soccer, rugby, and skiing were responsible for nearly two-thirds of the fractures among the 30 sporting activities that adolescents participated in. Upper extremity fractures were by far the most common injury accounting for 84% of all fractures with most being low-energy injuries and few requiring operative intervention.156 A retrospective study over a 16-year time period from an emergency department at a level 1 trauma center in the Netherlands examined risk factors for upper extremity injury in sports-related activities. Most injuries occurred while playing soccer and upper extremity injuries were most common. Risk factors for injury were young age and playing individual sports, no-contact sports, or no-ball sports. Women were at risk in speed skating, in-line skating, and basketball, whereas men mostly got injured during skiing and snowboarding.141 In Canada, soccer accounted for a significant proportion of injuries presented to Canadian Hospitals Injury Reporting and Prevention Program emergency departments during 1994 to 2004 with over 30% of these injuries presenting as fractures or dislocations.48 A study using data from the Dutch Injury Surveillance System revealed a substantial sports-related increase in the incidence rate of wrist fractures in boys and girls aged 5 to 9 and 10 to 14 years in the period from 1997 to 2009. The authors concluded that incidence rate of wrist fractures in childhood in this study population is increasing, mainly as a result of soccer and gymnastics at school and recommended that future sport injury research and surveillance data are necessary to develop new prevention programs based on identifying and addressing specific risk factors, especially in young athletes.34 
In the United States, football- and basketball-related injuries are common complaints presenting to pediatric emergency departments, with fractures occurring more frequently in football.95 In a 5-year survey of the NEISS-All Injury Program, injury rates ranged from 6.1 to 11 per 1,000 participants/year as age increased, with fractures and dislocations accounting for nearly 30% of all injuries receiving emergency room evaluation.92 

Recreational Activities and Devices

In addition to increasing participation in sports, new activities and devices have emerged that expose children to increased fracture risk. Traditional activities such as skateboarding, roller skating, alpine sports, and bicycling have taken on a new look in the era of extreme sports where such activities now involve high speeds and stunts. In addition, several recreational devices have been the focus of public health interventions and legislation because of their association with injuries in children. Many of these activities have safety equipment available but that does not assure compliance. Organizations such as the American Academy of Pediatrics and the American Academy of Orthopaedic Surgeons (AAOS) have issued position statements regarding the proper use and supervision of such devices, but it remains within the duty of the physician to educate and reinforce to patients and families to promote safety around these activities.82 

Playground Equipment

Play is an essential element of a child's life. It enhances physical development and fosters social interaction. Unfortunately, unsupervised or careless use of some play equipment can endanger life and limb. When Mott et al.97 studied the incidence and pattern of injuries to children using public playgrounds, they found that approximately 1% of children using playgrounds sustained injuries. Swings, climbers, and slides are the pieces of playground equipment associated with 88% of the playground injuries.86 
In a study of injuries resulting from playground equipment, Waltzman et al.150 found that most injuries occurred in boys (56%) with a peak incidence in the summer months. Fractures accounted for 61% of these injuries, 90% of which involved the upper extremity and were sustained in falls from playground equipments such as monkey bars and climbing frames. Younger children (1 to 4 years old) were more likely to sustain fractures than older children. 
Similar observations were made in a study by Lillis and Jaffe78 in which upper extremity injuries, especially fractures, accounted for most of hospitalizations resulting from injuries on playground equipment. Older children sustained more injuries on climbing apparatus, whereas younger children sustained more injuries on slides. 
Loder80 utilized the NEISS dataset to explore the demographics of playground equipment injuries in children. Monkey bars were the most common cause of fractures. In another study looking specifically at injuries from monkey bars, the peak age group was the 5- to 12-year-old group, with supracondylar humeral fractures being the most common fracture sustained.87 
The correlation of the hardness of the playground surface with the risk of injury has been confirmed in numerous studies.68,80,98,99 Changing playground surfaces from concrete to more impact-absorbing surfaces such as bark reduced the incidence and severity of head injury but increased the tendency for long bone fractures (40%), bruises, and sprains. Chalmers et al.23 determined that the height of the equipment was just as great a risk factor as the surface composition. Using a novel composite playground safety score, researchers from Hasbro Children's Hospital in Rhode Island found that the incidence of supracondylar humerus fractures was increased in their community with playgrounds with lower composite safety scores and suggested that improvements in playground infrastructure may potentially reduce the incidence of supracondylar humerus fractures, and other injuries in children.105 
Public playgrounds appear to have a higher risk for injuries than private playgrounds because they usually have harder surfaces and higher pieces of equipment,106 although playground injury was most likely to occur at school compared to home, public, and other locations.107 

Bicycle Injuries

Bicycle injuries are a significant cause of mortality and morbidity for children.109 Bicycle mishaps are the most common causes of serious head injury in children.154 Boys in the 5- to 14-year age group are at greatest risk for bicycle injury (80%). Puranik et al.109 studied the profile of pediatric bicycle injuries in a sample of 211 children who were treated for bicycle-related injury at their trauma center over a 4-year period. They found that bicycle injuries accounted for 18% of all pediatric trauma patients. Bicycle/motor vehicle collisions caused 86% of injuries. Sixty-seven percent had head injuries and 29% sustained fractures. More than half of the incidents occurred on the weekend. Sixteen percent were injured by ejection from a bicycle after losing control, hitting a pothole, or colliding with a fixed object or another bicycle. Fractures mainly involved the lower extremity, upper extremity, skull, ribs, and pelvis in decreasing order of incidence. Over the last decade, youth participation in mountain biking has seen an increase and with that so has the number of injuries related to mountain biking increased with many caused by unpredictable terrain and falls as one rides downhill.3,4 
The study by Puranik et al.109 pointed out an equally important issue related to bicycle safety as they detected that helmet use was disturbingly low (<2%). Other studies confirm the observation that fewer than 13% to 15% of children wear helmets while riding bicycles.41,113 The Year 2000 Health Objectives called for helmet use by 50% of bicyclists.21 Even as recently as 2003, the use of bicycle helmets was still below 20%.50 Research has shown that legislation, combined with education and helmet subsidies, is the most effective strategy to increase use of safety helmets in child bicyclists.19 As public awareness of both the severity and preventability of bicycle-related injuries grows, the goal of safer bicycling practices and lower injury rates can be achieved.109 
Bicycle spokes and handlebars are also responsible for many fractures and soft tissue injuries in children. D'Souza et al.39 and Segers et al.123 found that bicycle spoke injuries are typically sustained when the child's foot is caught in the spokes of the rotating wheel. Of 130 children with bicycle spoke injuries, 29 children sustained fractures of the tibia, fibula, or foot bone. Several had lacerations and soft tissue defects. D'Souza et al.39 suggested that a mesh cover to prevent the toes from entering between the spokes and a plastic shield to bridge the gap between the fork and horizontal upright could substantially decrease the incidence of these injuries. 

Skateboarding

Skateboarding and in-line skating have experienced a renewed surge in popularity over the past three decades. With the increasing number of participants, high-tech equipment development, and vigorous advertising, skateboard and skating injuries are expected to increase. There was an initial increase in the early 1980s, with a decrease after 1993. Since 1998, there has been an increase in the number of skateboard injuries.66 Because the nature of skateboarding encompasses both high speed and extreme maneuvers, high-energy fractures and other injuries can occur, as highlighted by several studies.43,104,108 Studies have shown that skateboarding-related injuries are more severe and have more serious consequences than roller skating or in-line skating injuries.104 In a study of skateboarding injuries, Fountain et al.43 found that fractures of the upper or lower extremity accounted for 50% of all skateboarding injuries. Interestingly, more than one-third of those injured sustained injuries within the first week of skateboarding. Most injuries occurred in preadolescent boys (75%) from 10 to 16 years of age; 65% sustained injuries on public roads, footpaths, and parking lots. In a study over a 5-year period of time using data from the National Trauma Data Bank, skateboarding injuries were associated with a higher incidence of closed head injuries and long bone fractures with children under age 10 more likely to sustain a femur fracture.83 Several reports43,122 have recommended safety guidelines and precautions such as use of helmets, knee and elbow pads, and wrist guards, but such regulations seldom are enforced. 
It was thought that formal skate parks could decrease the injury rate. However, a study by Sheehan et al.125 demonstrated that dedicated skate parks led to an increase in pediatric fractures referred to the hospital. The authors suggested that there should be closer supervision and training of children and more emphasis on limb protective gear. Lustenberger et al.83 did however find that helmet use and designated skateboarding areas decreased the incidence of serious head injury (Table 1-7). 
 
Table 1-7
Skateboard Safety Measures
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Table 1-7
Skateboard Safety Measures
Children younger than 5 years of age should not ride a skateboard
Children between 6 and 10 years of age should only ride with adult supervision
Use a quality skateboard and keep it in good working order
Learn proper falling and rolling techniques
Do not ride in traffic
 

From: Lovejoy S, Weiss JM, Epps HR, et al. Preventable childhood injuries. J Pediatr Orthop. 2012; 32(7):741–747, with permission.

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Roller Skates and In-line Skates

In a study of in-line skate and roller skate injuries in childhood, Jerosch et al.57 found that in a group of 1,036 skaters, 60% had sustained injuries. Eight percent of these were fractures, mostly involving the elbow, forearm, wrist, and fingers (78%). Fewer than 20% used protective devices, and most lacked knowledge of the basic techniques of skating, braking, and falling. In a larger study of 60,730 skating injuries in children, Powell and Tanz108 found that 68% of the children were preadolescent boys with a mean age of 11.8 years. Fractures were the most common injury (65%) and two-thirds of these involved the distal forearm. Two and a half percent required hospital admissions; 90% of these admissions were for a fracture. Similarly, Mitts and Hennrikus93 found that 75% of in-line skating fractures in children occurred in the distal forearm as a result of falls on the outstretched hand. One in eight children sustained a fracture during the first attempt at the sport. The orthopedic community has an obligation to educate the public on the need for wearing wrist guards when using in-line skates or roller skates. 
Over the last decade there has also been a new product known as skate shoes or “heelys” that has increased in popularity and with this a rise in injuries associated with the use of these devices.1 Ruth et al. (Ruth, Shah, & Fales, 2009) examined data over a 5-year period from the NEISS database for injuries related to skate shoes in children of ages 5 to 14. Most injuries in younger patients were fractures with the most frequent sites of fracture being the forearm and the wrist. 

In-line Scooters

Since 2000, a substantial increase in injuries related to nonmotorized scooters (kickboards) has been observed among children. The wheels of the scooter getting caught by uneven ground caused most of the scooter-related accidents, whereas most skateboard accidents occurred during attempted trick maneuvers. Protective gear was seldom used.24,88,119 Scooters seem to have a high incidence of collisions with motor vehicles.88 The recent motorizing of the scooters will only increase the severity of the injuries sustained. 

Trampolines

Trampolines enjoyed increasing popularity in the 1990s and are a significant cause of morbidity in children. Several studies have noted a dramatic increase in the number of pediatric trampoline injuries during the past 10 years, rightfully deeming it as a “national epidemic.”45,134 
Using the NEISS data, Smith134 estimated that there are roughly 40,000 pediatric trampoline injuries per year. Furnival et al.,45 in a retrospective study over a 7-year period, found that the annual number of pediatric trampoline injuries tripled between 1990 and 1997. In contrast to other recreational activities in which boys constitute the population at risk, patients with pediatric trampoline injuries were predominantly girls, with a median age of 7 years. Nearly a third of the injuries resulted from falling off the trampoline. Fractures of the upper and lower extremities occurred in 45% and were more frequently associated with falls off the trampoline. In another excellent study on pediatric trampoline injuries, Smith134 found that there was virtually a 100% increase in injuries from 1990 to 1995, with an average of more than 60,000 injuries per year. Younger children had a higher incidence of upper extremity fractures and other injuries. In a later study, Smith and Shields135 reported that fractures, especially involving the upper extremity, accounted for 35% of all injuries. Interestingly, more than 50% of the injuries occurred under direct adult supervision. More disturbingly, 73% of the parents were aware of the potential dangers of trampolines, and 96% of the injuries occurred in the home backyard. These researchers, along with others,45 rightly concluded that use of warning labels, public education, and even direct adult supervision were inadequate in preventing these injuries and have called for a total ban on the recreational, school, and competitive use of trampolines by children.17,134,135 (Table 1-8
 
Table 1-8
Trampoline and Moon Bouncer Safety Measures
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Table 1-8
Trampoline and Moon Bouncer Safety Measures
Although use of a net or ground-level trampoline may decrease injuries sustained while falling off of a trampoline, it does not prevent injuries sustained from collisions and twisting events
Single child trampolining or moon bouncing is safest
If the children play together in small groups on these devices, they should be of the same age and size
An adult should directly supervise trampoline and moon bounce use at all times
 

From: Lovejoy S, Weiss JM, Epps HR, et al. Preventable childhood injuries. J Pediatr Orthop. 2012; 32(7):741–747, with permission.

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Skiing Injuries

In a study of major skiing injuries in children and adolescents, Shorter et al.127 found that more than 90% of injured children were boys from 5 to 18 years of age. Sixty percent of the accidents occurred in collisions with stationary objects such as trees, poles, and stakes. Most injuries occurred in the afternoon, among beginners, and in the first week of skiing season. Fractures accounted for one-third of the total injuries sustained. The two main factors implicated in skiing injuries are excessive speed and loss of control; effective prevention efforts should target both of these factors. 

Snowboarding Injuries

Snowboarding runs a risk similar to skiing. Bladin et al.14 found that approximately 60% of snowboarding injuries involved the lower limbs and occurred in novices. The most common injuries were sprains (53%) and fractures (26%). Compared to skiers, snowboarders had 21/2 times as many fractures, particularly to the upper limb, as well as more ankle injuries and higher rates of head injury. The absence of ski poles and the fixed position of the feet on the snowboard mean that the upper limbs absorb the full impact of any fall. Wrist braces can decrease the incidence of wrist injuries in snowboarding.115 In addition, fractures of the lateral process of the talus can be seen in snowboarding ankle injuries.72 Of some concern, a recent study has shown that rates of snowboard injuries seem to be rising, whereas rates of ski injuries have been flat.51 

Motor Vehicle Accidents

This category includes injuries sustained by occupants of a motor vehicle and victims of vehicle–pedestrian accidents. 
The injury patterns of children involved in MVAs differ from those of adults. In all types of MVAs for all ages, children constitute a little over 10% of the total number of patients injured.70,119 Of all the persons injured as motor vehicle occupants, only about 17% to 18% are children. Of the victims of vehicle-versus-pedestrian accidents, about 29% are children. Of the total number of children involved in MVAs, 56.4% were vehicle–pedestrian accidents, and 19.6% were vehicle–bicycle accidents.35 
The fracture rate of children in MVAs is less than that of adults. Of the total number of vehicle–pedestrian accidents, about 22% of the children sustained fractures; 40% of the adults sustained fractures in the same type of accident. This has been attributed to the fact that children are more likely to “bounce” when hit.35 
Children are twice as likely as adults to sustain a femoral fracture when struck by an automobile; in adults, tibial and knee injuries are more common in the same type of accident. This seems to be related to where the car's bumper strikes the victim.18,22 MVAs do produce a high proportion of spinal and pelvic injuries.18 

All-terrain Vehicles (ATVs)

Recreational all-terrain vehicles (ATVs) have emerged as a new cause of serious pediatric injury. In 1988, the United States Consumer Product Safety Council signed an agreement with the ATV industry banning ATV use in children under 16 years of age, discontinuing production of three-wheeled ATVs, and promoting educational and safety programs. The consent decrees expired in 1998. An ATV Action Plan remained in place that prohibited manufacturers to market or sell three-wheeled ATVs, not market or sell adult-size ATVs to or for use by children younger than 16, promote training, and conduct safety education campaigns.5 Despite these efforts ATV accidents have increased over the last two decades.53 According to the 2007 report of the Consumer Product Safety Commission, serious ATV injuries in children younger than 16 years requiring emergency room treatment rose from 146,000 in 2006 to 150,900 in 2007. Using the Kids' Inpatient Database (KID) dataset, Killingsworth et al.61 showed that 5,292 children were admitted to a hospital in 1997 and 2000 (the 2 years for which KID data was available) resulting in 74 million dollars in hospital charges, with rates of hospitalization increasing 80% between these 2 years. In fact, using the Oregon State database, Mullins et al.100 showed that the number of patients who sought tertiary care for severe injuries caused by off-road vehicles doubled over a period of 4 years. In contrast to other etiologies of injury, children who sustained ATV-related fractures had more severe injuries and a higher percentage of significant head trauma, with 1% of these injuries resulting in inhospital death. These statistics point to the failure of voluntary safety efforts to date and argue for much stronger regulatory control. 
In their 11-year review of ATV injuries treated at a level 1 pediatric trauma center, Kute et al.65 determined that ATV accident-related admissions increased almost five times and overall fracture number increased four times over the study period; 63% of the 238 patients sustained at least one fracture. In a review of 96 children who sustained injuries in ATV-related accidents during a 30-month period, Kellum et al.59 noted age-related patterns of injury. Younger children (≤12 years) were more likely to sustain an isolated fracture and were more likely to sustain a lower extremity fracture, specifically a femoral fracture, than older children. Older children were more likely to sustain a pelvic fracture. Kirkpatrick et al.62 expressed concern about the frequency and severity of fractures about the elbow in their 73 patients injured in ATV accidents between 2001 and 2007: All six open fractures involving the upper extremity involved the elbow. In a recent review of the 2006 KID, Sawyer et al.118 found that despite the known risks associated with ATV use in children, their use and injury rate continue to increase. The injury rate for children from ATV accidents has increased 240% since 1997, whereas the spinal injury rate has increased 476% over the same time frame. The authors found that injuries to the spinal column occurred in 7.4% of patients with the most common level of fracture was thoracic (39%), followed by lumbar (29%) and cervical (16%). Pelvic fractures were the most common associated fractures, accounting for 44% of all musculoskeletal injuries, followed by forearm/wrist fractures (15%) and femoral fractures (9%). Despite educational and legislative efforts, children account for a disproportionate percentage of morbidity and mortality from ATV-related accidents. The sport of motocross has also been shown to have a high rate of musculoskeletal injuries requiring hospitalization in children.73 (Table 1-9
Table 1-9
Strategies to Improve All-terrain Vehicle (ATV) Rider Safety in Children
State-sponsored safety courses should be required
Always use a helmet
Never ride on paved roads shared by automobile traffic
Restrict riders till 16 years of age
No passenger
 

From: Lovejoy S, Weiss JM, Epps HR, et al. Preventable childhood injuries. J Pediatr Orthop. 2012; 32(7):741–747, with permission.

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The etiologic aspects of children's fractures are summarized in Figure 1-6 and Table 1-10
Figure 1-6
The incidence of fractures in children expressed as the four common etiologic categories.
 
Most fractures occur at home. The numbers are expressed as total patients per each age category.
 
(Reprinted from Worlock P, Stower M. Fracture patterns in Nottingham children. J Pediatr Orthop. 1986; 6(6):656–660, with permission.)
Most fractures occur at home. The numbers are expressed as total patients per each age category.
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Figure 1-6
The incidence of fractures in children expressed as the four common etiologic categories.
Most fractures occur at home. The numbers are expressed as total patients per each age category.
(Reprinted from Worlock P, Stower M. Fracture patterns in Nottingham children. J Pediatr Orthop. 1986; 6(6):656–660, with permission.)
Most fractures occur at home. The numbers are expressed as total patients per each age category.
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Table 1-10
Summary of Etiologic Factors in Children's Fractures
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Table 1-10
Summary of Etiologic Factors in Children's Fractures
Home environment
 Injuries
  83% of all children's injuries
 Fractures
  37% of all children's fractures
School environment
 Injuries
  Overall rate, 2.8–9.2% annually
  53% related to athletic events
  Peak age: Middle school group
 Fractures
  Occur in only 5–10% of all school-related injuries
  About 20% of all children's fractures
Motor vehicle accidents (MVAs)
 Injuries
  Children only 10% of all MVAs
  Of children's MVAs, only 17–18% were occupants; remainder were vehicle/pedestrian or vehicle/bicycle
 Fractures
  High incidence of femur fractures in vehicle–pedestrian accidents in children
  Children have a higher incidence of spinal and pelvic fractures with MVAs than with other mechanisms
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Gunshot and Firearm Injuries

Etiology
Gunshot or missile wounds arise from objects projected into space by an explosive device. Gunshot wounds have become increasingly common in children in the United States.1 In a sad reflection of the changing times and the newly pervasive gun culture, firearms are determined to be second only to motor vehicles as the leading cause of death in youths. In considering the prevalence of firearms in the United States, it has been estimated that there are about 200 million privately owned guns in the United States and that approximately 40% of US households contain firearms of some type.38 
In two reports from inner-city hospitals in the United States in the 1990s, most injuries resulted from random violence to innocent bystanders; the prime example was “drive-by shootings.”140,152 Few were self-inflicted, either voluntarily or accidentally. In a 1976 report on patients in a relatively rural setting in Canada, almost all the missile injuries were accidental, having been caused by the patient or a close friend or relative.76 
In the urban setting, handguns and rifles are the most common weapons.140,145,152 In the rural setting, the most common weapon is a shotgun.76 The firepower of these weapons has changed over the years. In one urban hospital reporting gunshot wounds from 1973 to 1983, most of the injuries were from .32- or .38-caliber weapons; only 5% were high-caliber or high-velocity weapons.103 In a later study of gunshot wounds from the same institution from 1991 to 1994, the incidence of injuries from high-caliber and high-velocity weapons (e.g., .357 Magnum, AK-47, and other assault rifles) had increased to 35%.152 
In the urban setting, the victims' ages ranged from 1 to 17 years, and most of the injuries were in children aged 12 to 14.103,140,145,152 In the rural setting, the patients were younger; the average age was 9 years.76 
Of 839 children sustaining gunshot wounds, 274 (32.6%) involved the extremities.103,140,145,152 Of the gunshot wounds that involved the extremities, 51.3% produced significant fractures.76,145,152 No single bone seemed to predominate, although most of the fractures were distal to the elbow.103,140,145,152 
Complications from Gunshot Wounds
The two most common complications were growth arrest and infection. Other complications included delayed union and malunion. The treatment of fractures associated with gunshot wounds in children is never simple. Bone defects, associated peripheral nerve injuries, and involvement of the joint can negatively influence outcomes.9 Considering the magnitude of many of these injuries, the infection rate for extremity wounds was low (about 7.3%). The type of missile did not seem to have any relation to the development of an infection.152 
In Letts and Miller's 1976 series, one-sixth of the patients had some type of growth disturbance.76 In a third of their patients, the missile was only in close proximity to the physis, but still appeared to cause a growth disturbance. In a 1995 report by Washington et al.,152 the incidence of missiles' growth arrest was exactly the same; however, all were a result of a direct injury to the physis by the missile. None of their patients with growth arrest had proximity missile wounds. The higher incidence of growth abnormalities in the 1976 series was because of the larger number of shotgun and hunting rifle injuries, which dissipate more of their energy peripheral to the missile track. 
In two of the studies in which patients were followed closely, all of the fractures ultimately healed.76,152 On the other hand, DiScala and Sege37 found in their review of children and adolescents who required hospitalization for gunshot wounds that almost half of them were discharged with disabilities. 
Prevention
Firearm-related injury and safety have received much attention nationally and internationally in the wake of the events over the last decade. In a 1998 report, Freed et al.44 analyzed the magnitude and implications of the increasing incidence of firearm-related injuries in children. They suggested a product-oriented approach, focusing on the gun, in an attempt to provide an efficient strategy of gun control and hence reduce the disturbing trend of firearm-related injuries and death among youths. Rather than modifying behavioral or environmental issues, which are more complex, they suggested focusing primarily on strategies that offset the accessibility and design of firearms. In brief, these strategies included reducing the number of guns in the environment through restrictive legislation, gun buy-back programs, gun taxes, physician counseling, and modifying the design of guns to make them more childproof and prevent unauthorized and unintended use. 

Evolving Epidemiology of Fractures in Children

Preventive Programs

While studying the epidemiology of fractures, it is important to focus on the etiology of fractures and the settings in which they occur. Fractures do not occur in a vacuum, and well-researched studies that analyze the physical and social environment in which they occur are extremely valuable. Efforts can be made toward creating a safer environment for play and recreation. It is hoped that by targeting these areas, programs can be designed to decrease the risk factors. 

National Campaigns

Several national organizations have developed safety programs. The foremost is the American Academy of Pediatrics, which has committees on injury and poison prevention and sports medicine and fitness that has produced guidelines for athletics,153 playgrounds, trampolines,17 ATVs,5 and skateboards.6 The AAOS has also produced a program designed to decrease the incidence of playground injuries. These programs offer background data and guidelines for various activities, but their effectiveness has not been fully studied. In addition, the AAOS, the Orthopaedic Trauma Association (OTA), and Pediatric Orthopaedic Society of North America (POSNA) have issued updated position statements regarding the safe use of ATVs, trampolines, skateboards, and in-line skating. 

Local Community Participation

To be effective, accident prevention programs require local participation and cooperation. They must be broad based, and they require considerable effort by members of the local community. In the United States, one effective program is the New York Health Department's “Kids Can't Fly” campaign, developed in response to the large number of injuries and deaths from children falling out of apartment house windows in the 1970s.137 This extensive program consisted of a good reporting system from hospital emergency rooms, with follow-up by public health personnel; a strong media campaign to educate the public; a door-to-door hazard identification program; and the distribution of low- or no-cost, easily installed window guards to families in high-rise apartments. The city required property owners to provide window guards in apartments where children of 10 years or younger lived. The success of this program was demonstrated by a 50% decrease in reported falls after 3 years and a 96% decrease after 7 years.10,137 
Over the past 30 years, Sweden has developed broader-based, community-oriented programs to decrease the incidence of all types of childhood injuries.12 The development of these pilot programs has been relatively easy in a country like Sweden because the population is homogeneous, the incidence of poverty is low, and the government is stable. The Swedish program had a three-pronged approach: Injury surveillance and prevention research; establishment of a safer environment for children through legislative regulation; and a broad-based safety education campaign. These programs have produced positive results. Schelp121 demonstrated a 27% reduction in home accidents in the municipality of Falkoping only 3 years after the establishment of a community-wide campaign. 
Effective prevention programs require local community participation and education. All the articles, lectures, and pamphlets in the world cannot help unless local communities make the necessary changes to decrease accident risks. 

Modern Day Data Systems may Provide Expanded Opportunities to Examine the Epidemiology of Pediatric Trauma

Several sources of administrative, national, and regional data have recently become available providing significantly improved investigation into various areas within pediatric trauma. The Healthcare Cost and Utilization Project (HCUP) is a family of databases including the State Inpatient Databases (SID), the Nationwide Inpatient Sample (NIS), and the KID. Although administrative data may lack clinical detail for certain purposes, these datasets provide a comprehensive overview of health care utilization in the United States and are available without purchase (http://www.ahrq.gov/research/data/hcup/index.html).139 The KID database has been increasingly used to examine the incidence of pediatric trauma as well as practice patterns in pediatric trauma. Data for KIDS are collected and published every 3 years, with data currently available for 1997, 2000, 2003, and 2006. KIDS is “nationally representative,” meaning that the database contains a large but incomplete sample of the hospital discharge records (3.1 million in 2006), which are then statistically weighted upward to reflect the complete population of pediatric discharges (7.6 million in 2006). In the United States, using the HCUP KID dataset, Galano et al.46 examined the face of pediatric inpatient trauma in 1997. They estimated that roughly 84,000 children were admitted for fracture care that resulted in about 1 billion dollars in hospital charges. Of some interest, more than 70% of children were treated at nonchildren's hospitals. In 2011 study, utilizing the 2006 HCUP KID dataset, Gao47 reported on lower extremity fractures requiring hospitalization and found there were about 11,500 admission records for children aged 0 to 20 with lower extremity fractures. Urban hospitalizations accounted for 93% of cases and 66% of admissions were to teaching hospitals in Gao's study. There was an increased mortality risk among patients cared for in nonteaching hospitals and hospitals located in a rural region. 
Several other databases including the United States Consumer Product Safety Commission's NEISS (http://www.cpsc.gov/library/neiss.html) have also been useful in providing information about the epidemiology of pediatric trauma. The NEISS provides a national sample from hospitals with patient information regarding emergency room visits related to an injury with associated consumer products. The information from the NEISS provides data necessary for surveillance efforts to identify problem areas, risk factors for injuries, and translation into prevention programs. Internationally, many countries have national health registries that can provide epidemiologic data on injury patterns. On a local level, many hospitals and hospital systems have created their own trauma and injury registries for clinical and academic use. One limitation to the currently available data sources is that they provide scant clinical detail, limiting broader utility as a source of health outcomes data in the field. Pilot efforts on an organizational level have also evaluated the feasibility of a national pediatric musculoskeletal trauma outcomes registry.149 
Trauma registries are another source for injury data that document clinical and demographic information regarding acute care delivered to hospitalized patients with injuries at trauma centers. These databases are designed to provide information that can be used to study the effectiveness and quality of trauma care and identify areas for quality improvement. Although the amount of information available through regional and national databases allowed is immense, the creation and maintenance of these registries require a significant amount of time and financial resources. Several limitations of these databases include the focus on adult over pediatric injuries and the data that does not always reflect population-based samples. Constructed in an attempt to fill such a role, the National Pediatric Trauma Registry (NPTR) was a multi-institutional database designed to provide a snapshot of physiologic and clinical information regarding pediatric injuries. The NPTR was functional for about 15 years and provided a source of important data in the realm of pediatric trauma.143 Attempts are being made to transform the NPTR into a more comprehensive database that will be called the National Trauma Registry for Children.20 Currently the American College of Surgeons National Trauma Data Bank serves as the largest database which does produce annual reports on pediatric injury from trauma centers from the United States and Canada (http://www.ntdb.org). In the future, databases such as these may provide the infrastructure needed to study pediatric musculoskeletal trauma care. 

Acknowledgment

With appreciation to Kaye Wilkins for previous work on this chapter. 

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Miscellaneous Resources

Trampolines and Trampoline Safety. Available at http://www.aaos.org/about/papers/position/1135.asp
ATV Position Statement. Available at: http://www.aaos.org/about/papers/position/1101.asp
Injuries from In-Line Skating and Skateboarding. Available at: http://www.aaos.org/about/papers/position/1127.asp
National Center for Injury Prevention and Control, US Centers for Disease Control and Prevention. Web-based Injury Statistics Query & Reporting System (WISQARS) Injury Mortality Reports, 1999–2010, for National, Regional, and States (September, 2012). Available at: http://www.cdc.gov/injury/wisqars/fatal_injury_reports.html. Accessed September 8, 2012.