Evaluating Children With Fractures for Child Physical Abuse

Fractures With High Specificity for Abuse

As shown in Table 1, certain fractures have high specificity for or strong association with child abuse, particularly in infants, whereas others may have less specificity.²¹ Rib fractures in infants, especially those situated posteromedially, and the classic metaphyseal lesions of long bones, have high specificity for child abuse. Fractures of the scapula, spinous process, and sternum also have high specificity for abuse but are uncommon.

Rib fractures are highly suggestive of child abuse. Most abusive rib fractures result from anterior-posterior compression of the chest. For this reason, rib fractures are frequently found in infants who are held around the chest, squeezed, and shaken. Rib fractures have high probability of being caused by abuse.^15,17,21 The positive predictive value of rib fractures for child abuse in children younger than 3 years was 95% in one retrospective study.²² Other less common causes of rib fractures in infants include significant trauma sustained during childbirth or a motor vehicle crash as well as minor trauma in infants who have increased bone fragility.^23–25

Cardiopulmonary resuscitation (CPR) has been proposed as a cause of rib fractures, but conventional CPR with 2 fingers of 1 hand rarely causes fractures in children.^26,27 Recent recommendations that CPR be performed using 2 hands encircling the rib cage have raised concerns that this technique might cause rib fractures. An analysis of infants who were discovered during autopsy to have rib fractures and had received 2-handed chest compressions antemortem suggested that 2-handed CPR is associated with anterior-lateral rib fractures of the third to sixth ribs.²⁸ In this small study, no posterior rib fractures were observed. The fractures in these infants were always multiple, uniformly involved the fourth rib, and were sometimes bilateral. Additional research is needed to examine the relationship between the 2-handed CPR technique and rib fractures.

Classic metaphyseal lesions (CMLs) also have high specificity for child abuse when they occur during the first year of life.^21,29 CMLs are the most common long bone fracture found in infants who die with evidence of inflicted injury.³⁰ CMLs are planar fractures through the primary spongiosa of the metaphysis. These fractures are caused when torsional and tractional shearing strains are applied across the metaphysis, as may occur with vigorous pulling or twisting of an infant’s extremity.³¹ Fractures resembling CMLs radiographically have been reported after breech delivery³² and as a result of treatment of clubfoot.³³

Depending on the projection of the radiograph, CMLs can have the appearance of a corner or a bucket-handle fracture. Acute injuries can be difficult to visualize radiographically. CMLs commonly heal without subperiosteal new bone formation or marginal sclerosis. They can heal quickly and be undetectable on plain radiographs in 4 to 8 weeks.³¹

Fractures With Moderate Specificity for Abuse

Although many children who have been abused will have only a single fracture,³⁴ the presence of multiple fractures, fractures of different ages and/or stages of healing, and complex skull fractures have moderate specificity for physical abuse. In addition, epiphyseal separations, vertebral body fractures, and digital fractures have moderate specificity for abuse. The presence of multiple fractures or fractures of different ages can be signs of bone fragility but should also evoke consideration of child abuse. Besides the predictive value of the particular pattern of fractures, many other factors, such as the history and the child’s age, must be considered when determining whether the injury was inflicted.

Common Fractures With Low Specificity for Child Abuse

Long bone fractures (other than CMLs), linear skull fractures, clavicle fractures, and isolated findings of subperiosteal new bone formation have low specificity for child abuse. In contrast, the single long bone diaphyseal fracture is the most common fracture pattern identified in abused children.^1,13,34

An understanding of the extent and type of load that is necessary to cause a particular long bone fracture can help to determine whether a specific fracture is consistent with the injury described by the caregiver.^35,36 Transverse fractures of the long bones are caused by the application of a bending load in a direction that is perpendicular to the bone, whereas spiral fractures are caused by torsion or twisting of a long bone along its long axis. Oblique fractures are caused by a combination of bending and torsion loads.³⁷ Torus or buckle fractures are the result of compression from axial loading along the length of the bone. Although earlier studies suggested that spiral fractures should always raise suspicion for child abuse,¹² more recent studies do not show that any particular fracture pattern can distinguish between abuse and nonabuse with absolute certainty.^16,38

Falls are common in childhood.³⁹ Short falls can cause fractures, but they rarely result in additional significant injury (eg, neurologic injury).^11,40–42 In a retrospective study of short falls, parents reported that 40% of the children before 2 years of age had suffered at least 1 fall from a height of between 6 inches and 4 feet. Approximately one-quarter of these children suffered an injury; bruises were the most common injury observed.⁴³

The femur, humerus, and tibia are the most common long bones to be injured by child abuse.^1,34 Femoral fractures in the nonambulatory child are more likely caused by child abuse, whereas these fractures in ambulatory children are most commonly noninflicted.^{10,16,43–45}

Certain femur fractures may occur as a result of a noninflicted injury in young children. Several studies have demonstrated that a short fall to the knee may produce a torus or impacted transverse fracture of the distal femoral metadiaphysis.^46,47 Oblique distal femur metaphyseal fractures have been reported in children playing in a stationary activity center, such as an Exersaucer (Evenflo, Picqua, OH).⁴⁸

In both ambulatory and nonambulatory children, under some circumstances, falls on a stairway can cause a spiral femoral fracture. For example, a fall down several steps and landing with 1 leg folded or twisted underneath a child can lead to excessive torsional loading of the femur and a spiral fracture.⁴⁶ In ambulatory children, noninflicted femoral fractures have been described in children who fell while running or who fell and landed in a split-leg position.⁴³

A fracture of the humeral shaft in a child younger than 18 months has a high likelihood of having been caused by abuse.^15,49,50 In contrast, supracondylar fractures in ambulatory children are usually noninflicted injuries resulting from short falls.¹⁵

Physicians should also be aware of a particular mechanism reported to produce a noninflicted spiral-oblique fracture of the humerus in 1 case report.⁵¹ When the young infant was rolled from the prone position to the supine while the child’s arm is extended, the torsion and stress placed on the extended arm appeared to cause a spiral-oblique fracture of the midshaft of the humerus.

Linear skull fractures of the parietal bone are the most common skull fracture among young children, usually children younger than 1 year.¹³ A short fall from several feet onto a hard surface can cause a linear, nondiastatic skull fracture.^19,52 The majority of linear skull fractures are not inflicted.⁵³ By contrast, complex or bilateral skull fractures are typical of nonaccidental trauma.

Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a heterogeneous family of diseases, usually caused by heterozygous mutations of the genes COL1A1 and COL1A2,⁵⁴ but mutations in these and other genes can cause autosomal recessive forms of OI. The COL1A1 and COL1A2 genes encode the chains of type I collagen, which forms the structural framework of bone. Although it is a genetic disorder, many children have de novo mutations or autosomal-recessive disease and no family history of bone fragility. In addition, the presentation of the disease within affected members of the same family can be quite variable. Phenotypic expression of the disease depends on the nature of the mutation, its relative abundance attributable to mosaicism, and its expression in target tissues.⁵⁵ Some types of OI involve reduced production of collagen, and the symptoms resolve or lessen after puberty.⁵⁶ Table 2 lists the various signs and symptoms that can be present in a case of OI.

The diagnosis of OI is often suggested by a family history of fractures, short stature, blue sclera, poor dentition, and radiographic evidence of low bone density or osteopenia. The fractures are most commonly transverse in nature, occurring in the shafts of the long bones. It is unusual to have multiple long bone fractures or rib fractures, particularly in infancy, without other clinical and radiographic evidence of OI.^57,58

OI has been misdiagnosed as child abuse.⁵⁹ On the other hand, OI is often suggested as the cause of fractures in children who have been abused. If fractures continue to occur when a child is placed in a protective environment, a more thorough evaluation for an underlying bone disease is needed. Child abuse is more common than OI,⁶⁰ and children with OI and other metabolic or genetic conditions may also be abused.^61,62

Preterm Birth

Preterm infants have decreased bone mineralization at birth, but after the first year of life, bone density normalizes.^63,64 Osteopenia of prematurity has been well described as a complication in low birth weight infants.⁶⁵ Infants born at less than 28 weeks’ gestation or who weigh less than 1500 g at birth are particularly vulnerable. Osteopenia of prematurity is multifactorial. Infants are also at risk if they receive prolonged (for 4 or more weeks) total parenteral nutrition, have bronchopulmonary dysplasia, and/or have received a prolonged course of diuretics or steroids.⁶⁶ Osteopenia commonly presents between 6 and 12 weeks of life. Osteopenia of prematurity can be ameliorated if infants are monitored closely and receive the nutritional and mineral supplementation initiated in the NICU.

Fractures associated with osteopenia of prematurity usually occur in the first year of life.⁶⁷ Rib fractures are typically encountered incidentally, whereas long bone fractures commonly present with swelling of the extremity. Osteopenia of prematurity can be associated with rickets, and in such cases, metaphyseal irregularities may be present. Although osteopenia of prematurity may make the infant more vulnerable to fracture, preterm infants are also at an increased risk of abuse.⁶⁸

Vitamin D Deficiency Rickets

Suboptimal vitamin D concentrations and rickets have been proposed as causes of fractures in infants.⁶⁹ Vitamin D insufficiency in otherwise healthy infants and toddlers is common. Approximately 40% of infants and toddlers aged 8 to 24 months in an urban clinic had laboratory evidence of vitamin D insufficiency (serum concentrations of 25-hydroxyvitamin D of ≤30 ng/mL).⁷⁰ Prolonged breastfeeding without vitamin D supplementation was a critical factor that placed these infants at risk, although increased skin pigmentation and/or lack of sunlight exposure may also have contributed. Rickets is characterized by demineralization, loss of the zone of provisional calcification, widening and irregularity of the physis, and fraying and cupping of the metaphysis.⁷¹ Despite the high prevalence of vitamin D insufficiency in infants and toddlers, rickets is uncommon.⁷²

The claim that vitamin D deficiency or insufficiency causes skeletal lesions that lead to the incorrect diagnosis of child abuse in infants is not supported in the literature. A systematic clinical, laboratory, and radiologic assessment should exclude that possibility.^73–75 Schilling et al found no difference in serum concentrations of 25-hydroxyvitamin D in young children with fractures suspicious for abuse and noninflicted fractures.⁷⁶ Vitamin D insufficiency was not associated with multiple fractures, in particular rib fractures or CMLs, the high specificity indicators of abuse. Perez-Rossello et al studied radiographs of 40 healthy older infants and toddlers with vitamin D insufficiency and deficiency and concluded that radiographic rachitic changes were uncommon and very mild. In this population, the reported fracture prevalence was zero.⁷²

In a study of 45 young children with radiographic evidence of rickets, investigators found that fractures occurred only in those infants and toddlers who were mobile.⁷⁷ Fractures were seen in 17.5% of the children, and these children were 8 to 19 months of age. The fractures involved long bones, anterior-lateral and lateral ribs, and metatarsal and metaphyseal regions. The metaphyseal fractures occurred closer to the diaphysis in the background of florid metaphyseal rachitic changes and did not resemble the juxtaphyseal corner or bucket handle pattern of the CML. In infant fatalities in which abuse is suspected, rachitic changes appear to be rare histologically.⁷⁸

Osteomyelitis

Osteomyelitis in infants can present as multiple metaphyseal irregularities potentially resembling CMLs.⁷⁹ Typically, the lesions become progressively lytic and sclerotic with substantial subperiosteal new bone formation. Other signs of infection are often present, such as fever, increased erythrocyte sedimentation rate, elevated C-reactive protein concentration, and elevated white blood cell count.

Fractures Secondary to Demineralization From Disuse

Any child with a severe disability that limits or prevents ambulation can be at risk for fractures secondary to disuse demineralization, even with normal handling.^80,81 The fractures are usually diaphyseal rather than CMLs. Often, these fractures occur during physical therapy and range-of-motion exercises. It can be difficult to distinguish between inflicted and noninflicted fractures occurring in these children. At the same time, children with disabilities are at an increased risk of being maltreated.^82–84 When multiple or recurrent fractures occur in a disabled child, a trial change in caregivers may be indicated to determine whether the fractures can be prevented. This is an extreme intervention and should be reserved for unusual circumstances.⁶³

Scurvy

Scurvy is caused by insufficient intake of vitamin C, which is important for the synthesis of collagen. Although rare today because formula, human milk, fruits, and vegetables contain vitamin C, scurvy may develop in older infants and children given exclusively cow milk without vitamin supplementation and in children who eat no foods containing vitamin C.^85–87 Although scurvy can result in metaphyseal changes similar to those seen with child abuse, other characteristic bone changes, including osteopenia, increased sclerosis of the zones of provisional calcification, dense epiphyseal rings, and extensive calcification of subperiosteal and soft tissue hemorrhages, will point to the diagnosis of scurvy.

Copper Deficiency

Copper plays a role in cartilage formation. Copper deficiency is a rare condition that may be complicated by bone fractures. Preterm infants are born with lower stores of copper than term infants, because copper is accumulated at a faster rate during the last trimester.⁸⁸ Copper insufficiency may be observed in children with severe nutritional disorders, for example, liver failure or short gut syndrome.⁸⁹ This deficiency is not likely to be observed in full-term children younger than 6 months of age or preterm infants younger than 2.5 months of age, because fetal copper stores are sufficient for this length of time. In addition, human milk and formula contain sufficient copper to prevent deficiency. Psychomotor retardation, hypotonia, hypopigmentation, pallor, and a sideroblastic anemia are some of the characteristic findings of copper deficiency in infants. Radiologic changes that should lead to further evaluation for possible deficiency include cupping and fraying of the metaphyses, sickle-shaped metaphyseal spurs, significant demineralization, and subperiosteal new bone formation.

Menkes Disease

Menkes disease, also known as Menkes kinky hair syndrome, is a rare congenital defect of copper metabolism.⁹⁰ Menkes disease is an X-linked recessive condition and occurs only in boys. Although it has many of the features of dietary copper deficiency, anemia is not associated with Menkes disease. Metaphyseal fragmentation and subperiosteal new bone formation may be observed on radiographs, and the findings may be difficult to distinguish from fractures caused by abuse.⁹¹ Other signs of Menkes disease include sparse, kinky hair, calvarial wormian bones, anterior rib flaring, failure to thrive, and developmental delay. A characteristic finding is tortuous cerebral vessels. Intracranial hemorrhage can occur in Menkes disease but has not been reported in infants with copper deficiency.

Systemic Disease

Chronic renal disease affects bone metabolism because children with chronic renal disease may develop a metabolic acidosis that interferes with vitamin D metabolism. Chronic renal disease can cause renal osteodystrophy resulting in the same radiographic changes as nutritional rickets. Because chronic liver disease (eg, biliary atresia) interferes with vitamin D metabolism, such children may be at an increased risk of fractures. Fanconi syndrome, hypophosphatasia, hypophosphatemic (vitamin D resistant) rickets, hyperparathyroidism, and renal tubular acidosis also cause clinical variants of rickets.

Temporary Brittle Bone Disease Hypothesis

Physicians should be aware of alternative diagnoses that are unsupported by research but are sometimes suggested when an infant has unexplained fractures. In 1993, Paterson proposed that some infants may be born with bones that are temporarily more fragile or vulnerable to fracture in the context of normal handling, which he called “temporary brittle bone disease.”⁹² Paterson suggested that some trace element deficiency, such as copper or a transient collagen immaturity, caused the disease but provided no scientific data that confirmed his hypotheses and offered no specific test that confirmed temporary brittle bone disease.⁶¹ Subsequent studies did not support his hypotheses, and his case analysis has been refuted.^57,93–95

Miller hypothesized that temporary brittle bone disease is a result of fetal immobilization or intrauterine confinement that leads to transient bone loss or osteopenia.^96,97 In support of his hypothesis, he reported that 95% of 21 infants with multiple unexplained fractures had decreased fetal movements, according to their mothers.^97,98 Although he used bone densitometry in each patient as a basis for his conclusions, none of the patients had had bone densitometry performed at the time of the fracture. The testing was performed 8 to 21 weeks later, and no infants were tested before 5 months of age. In addition, bone densitometry standards have not been established for infants. He relied on the mother’s history of decreased fetal movements and provided no independent measurements of those movements. Palacios and Rodriguez found no evidence that oligohydramnios affects bone mass of the fetus, probably because fetal movement is only restricted in the last trimester of pregnancy by oligohydramnios and because the mechanical loading on the bones stimulating bone formation is conserved.⁹⁹

History of Present Illness

It is essential to obtain a detailed history to determine how an injury occurred. If an injury in a nonverbal child was witnessed, the caregiver should be able to provide details about the child’s activity and position before an injury and the child’s final position and location after the injury occurred.⁴⁶ Verbal children with concerning fractures should be interviewed apart from caregivers and ideally by a professional who is skilled in forensic interviewing.

A comparison of the histories provided by caregivers of children with noninflicted femoral fractures and by caregivers of children whose injuries were caused by abuse is instructive. When an injury was caused by abuse, the caregiver provided either no history of an injury or related a history of a low-energy event. By contrast, 29% of the caregivers of children with noninflicted injuries provided some high-energy explanation, such as a motor vehicle collision or that the child fell from a height.¹⁶ Most of the low-energy mechanisms provided for the noninflicted injuries involved falls including stair falls and siblings landing on the femur during play.^16,46

The child’s response to the event may also provide important clues about the etiology. The majority of children with long bone fractures will have some swelling, pain, or other signs, such as decreased use of the extremity, suggesting a fracture.^100,101 Some children, however, will have minimal external signs of injury.¹⁰² The absence of any history of injury, a vague description of the event, a delay in seeking care, the absence of an explanation for an injury particularly in a nonambulatory child, or an inconsistent explanation should increase the physician’s concern that an injury was caused by child abuse (see Table 3).^13,16

Past Medical History

The past medical history is important and should include details about the mother’s pregnancy. If the child was born preterm, the infant’s bone mineral content may be reduced, and the infant may be at risk for fracture. A history of total parental nutrition, hepatobiliary disease, diuretic therapy, hypercalciuria, or corticosteroids may make the bones of a low birth weight infant even more vulnerable to fracture. In addition, chronic diseases, such as renal insufficiency or metabolic acidosis, malabsorption, cerebral palsy or other neuromuscular disorders, genetic diseases that affect skeletal development, or any illness that limits mobility, may affect bone strength. A thorough dietary history and history of medications that can predispose to fractures are important. The physician should inquire about previous injuries including bruises and determine the child’s developmental abilities, because children who are not yet mobile are much more likely to have fractures caused by abuse.

Family History

A family history of multiple fractures, early-onset hearing loss, abnormally developed dentition, blue sclera, and short stature should suggest the possibility of OI.

Social History

The physician should obtain a complete psychosocial history, including asking who lives in the home and who has provided care for the child. The history should inquire about intimate partner violence, substance abuse including drugs and alcohol, mental illness, and previous involvement with child protective services and/or law enforcement.

Physical Examination

The child should have a comprehensive physical examination, and the growth chart should be carefully reviewed. Abnormal weight may suggest neglect or endocrine or metabolic disorders. Any signs or symptoms of fractures, such as swelling, limitation of motion, and point tenderness should be documented. The physician should do a complete skin examination to look for bruises and other skin findings because bruises are the most common injury caused by child abuse. The majority of children with fractures do not have bruising associated with the fracture; the presence or absence of such bruising does not help to determine which fractures are caused by child abuse.^103,104 Bruising in a child who is not yet cruising or bruising in unusual locations, such as the ears, neck, or trunk should raise suspicion for child abuse.^105,106 The child should be examined for other injuries caused by child abuse, in addition to signs of other medical conditions associated with bone fragility. Blue sclerae are seen in certain types of OI. Sparse, kinky hair is associated with Menkes disease. Dentinogenesis imperfecta is occasionally identified in older children with OI.