The Radiographic Approach to Child Abuse
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- Dwek, J.R. Clin Orthop Relat Res (2011) 469: 776. doi:10.1007/s11999-010-1414-5
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Osseous injuries are a major facet of child abuse and in most patients radiographic imaging plays a major role in diagnosis. While some injuries are typically produced as a result of excessive and inappropriate force other injuries are nonspecific in terms of their causation, but become suspicious when the history provided by the caretakers is inconsistent with the type of injury produced.
I detail the radiographic imaging of the more characteristic of the highly specific injuries, discuss the major issues that relate to some moderate- or low-specificity injuries, and describe several diseases that mimic abuse.
A review of the current and recent literature focused on the radiographic imaging of child abuse was performed by searching the National Library of Medicine database at pubmed.gov. Keywords used included: radiology, fracture, child abuse, and/or nonaccidental trauma.
Injuries that are highly specific for the diagnosis of abuse include metaphyseal corner fractures, posteromedial rib fractures, and sternal, scapular, and spinous process fractures. Lesions of moderate specificity include, among other injuries, multiple fractures of various ages and epiphyseal separations. Long-bone fractures and clavicular fractures, while common, are of low specificity. In addition to the appropriate accurate diagnosis of these injuries, several diseases and syndromes may mimic abuse due to the similarity in the radiographic picture.
Stratification of fractures sustained in child abuse according to specificity and an understanding of the several diseases that mimic abuse are helpful in the accurate diagnosis of child abuse.
Level of Evidence
Level V, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.
Whether mental or physical, trauma is central to all cases of child abuse. Much of that trauma results in musculoskeletal injuries, which places the orthopaedic surgeon in a primary position in the recognition and treatment of these injuries. In most patients radiographic imaging plays a major role in diagnosis. Some injuries are typically produced as a result of excessive and inappropriate force on the tender skeleton of a child. These injuries are characteristic of child abuse and include the classic metaphyseal lesion (CML) and posteromedial rib fractures. Other injuries, which are in themselves nonspecific in terms of their causation, become highly suspicious when the history provided by the caretakers is inconsistent with the type of injury produced. A toddler’s fracture of the tibia in an infant who is not yet ambulatory and therefore not “toddling” would be such an injury. Another example of such a history-injury discordance is a complex skull fracture in an infant who sustained a fall from a bed [24, 40, 49].
The most important and frequently utilized system of fracture classification as it relates to abuse was detailed by Dr. Paul Kleinman and separates various fractures into broad categories of high, moderate, and low specificity for the ultimate diagnosis of child abuse .
In this article, I will detail the radiographic imaging of the more characteristic highly specific injuries and discuss the major issues that relate to some moderate- or low-specificity injuries. In addition, I will discuss several mimics of abuse with which the orthopaedic surgeon should be familiar and should recognize.
Search Methods and Criteria
The database of the National Library of Medicine at http://www.pubmed.gov was used to identify articles pertaining to the radiographic diagnosis of child abuse. The initial search terms used were “fracture AND radiology AND (child abuse OR nonaccidental trauma) NOT (brain OR head)”. This search returned 300 citations. Case reports were excluded (n = 57) unless describing a specific radiographic finding (n = 1), leaving a total of 243 citations (81%). Reviews were excluded (n = 48), leaving a total of 195 citations (65%). Ninety-seven citations were then excluded as they dealt with topics not germane to a radiological musculoskeletal review such as those papers dealing with abdominal, neurologic or psychiatric or treatment issues. A total of 98 citations remained, all of which were reviewed in full by the author. From these 98 citations, 44 articles (15% of original 300) were used to form the basis of this review. Many of these citations were letters and commentaries on current major controversies centering on alternative explanations for highly suspicious fractures currently labeled as due to child abuse. Because of the importance of this discussion these citations were considered in depth and the most salient observations included here. Those excluded from the subset of 98 citations were articles that repeated prior observations, or those which on review did not present material germane or of a sufficient importance to include in this focused review. This review was augmented by scientific papers describing facets of diseases such as osteogenesis imperfecta which are important differential diagnostic possibilities as well as information from Kleinman’s authoritative text DiagnosticImaging of Child Abuse  to furnish the orthopaedic surgeon with a complete and well-rounded review.
“Babygram” examinations include the entire body or large parts of it imaged together on one film. This causes loss of detail at the periphery of the field of view since the beam becomes highly angulated to the anatomic part in question. Furthermore, and probably more importantly, the radiographic technique needed for different body parts depends on the density of the body part in question so that the technique used to image the thorax is very different from the technique usually used on the extremities. The extremities are therefore incorrectly exposed when included on an image of the chest and abdomen. Due to these two main factors, “babygram” examinations are not considered sufficient for diagnosis [3, 36].
CT scanning is frequently necessary to evaluate for other injuries, such as intracranial and solid organ injury, and is very efficacious for confirmation of fractures that might be subtle radiographically. This is especially so with the high detail afforded by multidetector scanners. CT images should be carefully evaluated for fractures that might not be well evident by conventional radiography. The linear lucency and the periosteal reaction and callus associated with a healing fracture may be evident. In the courtroom, three-dimensional (3D) reconstructions tend to be more highly intelligible for the layman jury member and so can be highly valuable pieces of information. Aggressive use of 3D reconstructions is recommended at the time of imaging since archiving of scan data varies between institutions and high-quality reconstructions may not be possible later on.
Bone scintigraphy is also a useful adjunct. Its main contribution is its high sensitivity, which allows diagnosis of more subtle fractures that may not be radiographically evident. Fractures at the level of the physis, however, may be obscured by the normal high uptake in the region of the growth plate.
Specificity of injuries for child abuse
Classic metaphyseal lesions
Multiple rib fractures especially posterior
Spinous process fractures
Fractures in various stages of healing
Vertebral body fractures and separations
Complex skull fractures
Subperiosteal new bone formation
Long-bone shaft fractures
Linear skull fractures
Posteromedial Rib Fractures
Metaphyseal Corner Fractures
Along with the posteromedial rib fracture, the CML is the most salient form of child abuse that can be visualized by imaging. Histologically, the fracture plane dissects on the metaphyseal side along the zone of provisional calcification, tearing it off, usually incompletely . At the periphery, it usually extends slightly into the metaphysis proper due to the tight attachment of the periosteum at the level of the physis.
Only designated a moderate-specificity injury, the epiphyseal separation fracture requires special mention since it is often overlooked and the images are frequently misinterpreted by those who are not comfortable with pediatric imaging.
In an epiphyseal separation, the fracture occurs through the cartilaginous physis, usually with displacement of the epiphysis. Since the epiphysis is frequently not ossified or only slightly ossified, the displacement may not be apparent to the casual observer. At the shoulder where this type of injury is frequent, there may be a subtle malalignment of the metaphysis to the glenoid. Delayed images will frequently show subperiosteal hemorrhage along the humeral shaft and then the injury will be more obvious, but at times only subtle irregularity on the metaphyseal end of the physis may be present .
Multiple Fractures and Fractures of Various Ages
The physician must bear in mind the erroneous diagnosis of abuse can be devastating for a family. Although only moderately specific for child abuse, multiple fractures and fractures in various stages of healing are an important topic, as much for the diagnosis of child abuse as for identifying what is not child abuse.
Clearly, when there are multiple fractures in an infant without a good history of trauma, a high index of suspicion is necessary. Each fracture must be evaluated closely for its type and stage of healing. The diagnosis of abuse can be made when highly specific injuries are among the injuries identified, whether soft tissue or osseous. At that point, the diagnosis of abuse becomes more secure. It is important to recognize, however, while fractures such as CMLs or posteromedial rib fractures are highly specific, low-specificity long-bone fractures are very common.
In general, the usual time course of fracture healing is as follows: 4 to 10 days for resolution of soft tissue swelling; 10 to 14 days for subperiosteal new bone formation; 14 to 21 days for immature or soft callus; loss of fracture line definition at roughly 14 to 21 days; and greater than 21 days for mature or hard callus. In infants, the process is markedly accelerated . Newborns may show callus within 4 days , as evidenced by early callus in clavicular fractures sustained during delivery.
Variability in the extent of callus is also related to motion at the fracture site so that, in a fracture that is immediately immobilized, callus will be minimal unless the periosteum is stripped off the osseous cortical surface. Trauma in abused children tends to be repetitive without the victim coming immediately to medical attention and treatment. Callus in these cases tends to be abundant .
The bony mineralization should be evaluated. Callus may be markedly delayed in osteopenic patients  due to poor nutrition or other deficiencies of vitamin D or calcium.
Long-bone fractures are low-specificity lesions for child abuse. The low specificity belies their true importance as they are common in abused children. Estimated frequency varies in the medical literature. Estimates for femur fractures in children younger than 1 year due to abuse range in the medical literature from 39% to 93% [55, 66], although a recent report gives the incidence as only 11% in a Canadian population .
Spiral fractures have come under particularly intense scrutiny as being pathognomonic for abuse, but such is not the case. Spiral fractures and transverse fractures are equally common in abused children .
Dalton et al.  stressed the suspicious nature of femoral fractures in children younger than 3 years and emphasized the need for thorough followup investigation. In their patient population of 138 children with femoral fractures, the initial cause was abuse in only 10% of the children. After a more thorough investigation, the percentage of cases due to abuse increased to 31%. When femoral fractures sustained from a clear accidental traumatic episode or underlying medical condition were omitted, the percentage increased to 44%. Interestingly, 68 of the 138 patients (67%) were admitted to the orthopaedic service, of which 14 cases were confirmed as abuse later in the hospitalization. An additional six cases were later identified as abuse in the Child Abuse Registry . Clearly, the orthopaedic surgeon should have a high suspicion of abuse when treating an infant with a femoral fracture and the surgeon should remain alert throughout the hospitalization and even thereafter.
It is frequently most helpful to obtain followup radiographs. In most cases, the fracture line becomes more evident with periosteal reaction. Care is again mandated since, especially in cases where the extremity was quickly immobilized during treatment, the degree of callus may be minimal. Furthermore, in areas where the fracture is intraarticular, subperiosteal reaction will not be present .
Subperiosteal new bone formation is physiologic and normal in infants 1 to 5 months old. It is smooth and most commonly is seen along the diaphysis of the humerus, femur, and tibia. It is usually but not exclusively bilateral and is related to the rapid growth of infants.
Although physiologic subperiosteal new bone formation occurs up to 5 months old, a progression is usually observed in its appearance. Immature subperiosteal new bone is a thin hazy area of increased density separated from the cortex by a thin lucency. This type predominates in younger infants 1 to 4 months old. Subperiosteal new bone formation at 4 to 5 months is actively being incorporated into the bone and, similar to normal fracture callus, will progressively calcify and fill in, and it is this appearance that predominates later on. When subperiosteal new bone formation is seen, it should be closely examined for focality and bilaterality, as well as its appearance relative to the patient’s age. Physiologic subperiosteal new bone formation should not be greater than 2 mm in thickness .
Mimics of Abuse
Rickets is a very common cause of osteopenia and may be recognized by its effect on the physis. The physis is frayed and the white line of the zone of provisional calcification is lost. In severe cases, the physis is cupped. With better nutrition, the zone of provisional calcification recovers, but physeal irregularity remains for a period of time.
Osteopenia is commonly present in premature children and other hospitalized children. Premature children can sustain multiple fractures including classic CMLs. Chronic renal or liver disease can also cause deficient bone mineral density and rickets. These patients may also sustain lesions that would ordinarily be suspicious of abuse. Injuries in these patients require a detailed clinical and social history to differentiate injuries sustained as a result of normal daily care from abuse.
Fractures in the hospital are not uncommon and difficulty arises when, soon after discharge, the patient returns to the emergency room with fractures, frequently located in the long bones. Chronically ill patients while in the hospital may not be handled as often as they are at home and accidents inevitably are common. However, chronically ill patients are also at increased risk for abuse . Dating the fracture as accurately as possible is very important. A fracture showing advanced callus is not likely to have been sustained at home if the patient has been home less than 2 weeks. However, soft tissue swelling seen at the site of a fracture with no evidence of subperiosteal new bone formation is more suspicious, depending on the time since discharge. In any case, a posteromedial rib fracture should not occur as it is associated with a very specific mechanism unlikely to be duplicated as a result of daily care.
When faced with a case with multiple fractures, an effort should be made to roughly date each fracture. An assiduous search should be made for those higher-specificity fractures such as CMLs. If posteromedial rib fractures are suspected but not conclusively seen on plain film, multidetector-row CT can be very helpful and diagnostic.
Osteogenesis imperfecta (OI) is a rare disease writ large when the differential diagnosis of child abuse is considered. The cardinal feature of OI is increased bone fragility and, as such, must be considered when considering an infant with multiple fractures.
OI is classified according to the classification of Sillence et al. [59, 60], which for many years included only four types divided on both clinical and radiographic grounds. The Sillence classification describes a spectrum of disease rather than a strict system based on objective scientific identities. Type 1 is the most mild and patients have normal stature with little or no deformity. Type 2 is lethal in the perinatal period with beaded ribs, compressed deformed long bones, and minimal skull mineralization. Type 3 is of moderate severity with deformity generally present at birth. Type 4 is of mild to moderate severity with variable short stature and deformity. While with Types 2 and 3 the diagnosis is rarely in doubt, Types 1 and 4 engender considerable difficulties since both can be quite mild with little or no deformity present in infancy.
Types 1 to 4 are all caused by mutations in either the COL1A1 or COL1A2 gene, which encode for formation of the procollagen alpha-1 or alpha-2 chain. Two alpha-1 and one alpha-2 chains form the triple helix of collagen 1, which is the major contributor to the normal collagen matrix in bone.
Biochemical or mutation analysis is capable of identifying approximately 90% to 95% of patients with Types 1 to 4. The number is steadily increasing. However, recent descriptions of several new types of OI have changed the landscape.
Type 5 is typified by grossly hypertrophic callus about fractures and curious ossification of the interosseous membrane in the forearm . It is usually moderate in severity, although some variability can be observed. It is not a mutation in collagen 1 and is not identifiable by either mutation or biochemical testing aimed at collagen 1.
Type 6 is moderate in severity and indistinguishable from Type 4 clinically . It is not identifiable by mutation or collagen biochemical analysis. On microscopy of biopsied bone, it is indicated by a characteristic mineralization defect in bone.
Two new types classified as Types 7 and 8 are caused by abnormal posttranslational modification of the collagen molecule and are not identifiable by the traditional OI mutation or biochemical analysis. Both of these types manifest severe phenotypes with severe bone fragility. Metaphyseal changes and bulbous “popcorn” epiphyses, in which irregular dense calcifications are present, have been described . Given the severity of these types, they should not cause confusion when considered with respect of child abuse.
The complexity and variability present in OI make differentiation from abuse very challenging and both mutation and biochemical collagen analysis are frequently performed. Since the tests are only about 90% to 95% sensitive, the results can be unsatisfying and lead to confusion when trying to differentiate abuse from OI. However, several important points may be made.
While rib fractures can occur, it is generally in the more severe types. Fractures are usually lateral and are uncommon posteromedially. Posteromedial rib fractures even in a child with OI should be taken very seriously and, except in moderate to severe cases of OI, or in the face of severe osteopenia are highly suspicious for abuse because of the typical mechanism needed to produce those fractures. In severe OI, no mechanism is needed to explain a fracture, but in mild cases the mechanism of injury reigns supreme and must be considered.
CMLs are also highly suspicious. In epiphyseal cartilage, collagen 2 predominates. At the physeal level, collagen 1 is not present  and is produced in the metaphyses . As such, the most fragile portion of the bones of a patient afflicted with OI is not the physes but the midshaft, where fractures are more frequent. CML-type injuries are extraordinarily rare in OI and are even more rare, if they occur at all, in children younger than 1 year . For a CML to occur, in the face of trauma, the physis and zone of provisional calcification need to have greater weakness when compared to the diaphyses and this is not usually the case in OI. There have been no reports in the literature describing an infant with OI sustaining a true CML.
Even beyond the limits of biochemical and mutational testing, it is clear there are certain types of fractures that remain highly specific for abuse and are extremely suspicious when encountered in an infant. It should be recognized OI is, in the end, a rare disease and it is rarer still to be one of the 5% to 10% of patients with negative biochemical and mutational testing. Therefore, while OI is not ruled out as the result of negative laboratory analysis, any fracture must be considered very carefully if the patient is an infant and an appropriate history is not provided.
OI has also been called brittle bone disease in the common parlance. A separate term, temporary brittle bone disease (TBBD), refers to a report by Colin Paterson, a Scottish physician, of infants with suspicious fractures who, by his account, were not abused. According to Paterson, TBBD affects children under 6 months of age who sustain fractures during the course of normal handling and care and later no longer fracture [53, 54]. Paterson became a feature of many court cases in the United Kingdom and other countries in which the defense of TBBD was advanced, many times successfully. He emphasized the fractures occurred without a history of trauma or visible evidence of trauma, such as bruising, and without attendant internal injuries and the caregivers all denied wrongdoing . His theory has been severely criticized on each of his points [1, 44]. Many abused children lack bruising, and while bruising is a helpful indicator of trauma, fractures occur frequently in the absence of bruising at any age. In addition, although associated injuries such as solid organ injury and retinal hemorrhages are common, it is by no means the rule. Finally, abusers tend to deny any culpability, some even after being found guilty in a court of law and in the face of overwhelming evidence. Because of his single-minded testimony at trial in support of this diagnosis, which included a lack of appropriate review of the records, among other inadequacies, Paterson was forbidden to act as an expert witness in the United Kingdom . Later, in 2004, he was “struck out,” meaning his medical licensure was lifted . In the United States, the TBBD defense cannot be used in many states’ courts of law and has been discredited.
Dr. Marvin Miller, an adherent of the TBBD concept, has advanced a possible theory that proposes a temporary state of increased bony fragility related to decreased fetal movement [46, 47]. His theory has been criticized for methodologic errors, including an incomplete description of the injuries, a subjective history of decreased fetal movement, and a long delay between bone mineral density measurements and the time of trauma . In addition, his use of bone mineral density measurements is flawed in itself, as bone mineral density measurement is unreliable in young infants [16, 44]. The most recent normative values do not include values for those younger than 5 years [17, 44].
Most recently, Keller and Barnes  questioned whether neonatal rickets, mild in nature and related to decreased vitamin D in breast-feeding mothers, can be blamed for fractures occurring early in life. This contention has been criticized by Slovis and Chapman  on several counts, including a lack of observable findings of rickets that would include fraying and cupping of the physis on the published images from the original article. Indeed, one of the images of the distal ulna is claimed to show cupping consistent with rickets, but cupping of the distal ulna is a normal variant not associated with rickets as the sole finding . Keller and Barnes  have since responded in kind, noting there are, by their account, other findings of rickets on the published images, among other assertions. At this point, the implication of these reports and replies is still unclear, but several points may be made. First, the theory of neonatal rickets as an explanation of CML-type injuries, if true, should only apply in those infants younger than 6 months since, over that age, most children have nutritional sources other than breast milk. Second, it should not apply in those infants younger than 6 months who are not breast fed. Third, a posteromedial rib fracture remains highly specific for abuse. Finally, each radiograph must be assiduously examined for even mild signs of rickets, which would include cupping and fraying of the metaphyses, a frayed bulbous appearance of the anterior ends of the ribs (rachitic rosary), and undermineralization of the bony structures. Note is made, in the majority, newborn bones are generally more sclerotic in appearance, with thick cortices and small medullary cavities, when compared to the bones of toddlers and children.
Mimics of abuse include conditions causing decreased sensation, including spinal dysraphism and congenital insensitivity to pain. In the former case, the diagnosis is usually known, but rarely an infant may present with a lower extremity fracture related to an undiagnosed diastematomyelia or other myelodysplasia. In congenital insensitivity to pain, multiple fractures may occur related to abnormal pain sensation. This rare syndrome can have both dominant and recessive inheritance, and injuries may mirror those seen in abuse [42, 63]. A diligent neurologic examination and clinical history that uncovers the patient’s lack of pain sensation should provide adequate differentiation from abuse.
Congenital syphilis causes fragmentation of the metaphyses and subperiosteal new bone formation along the diaphyses in newborns . Both findings can simulate those seen in abuse. Clues to the correct diagnosis are the presence of Wimberger’s sign, seen as metaphyseal lucency in the medial subphyseal portion of the proximal tibia. It is usually bilateral and the defect spares the most recently formed few millimeters of the bone bark  and so should not be misconstrued as a true CML. Other radiographic abnormalities include trophic irregular metaphyseal lucent bands and focal lytic lesions, which represent syphilitic gummas, clearly not present in abuse.
Scurvy , vitamin A intoxication, Caffey’s disease, leukemia, and treatment with prostaglandin E all cause subperiosteal new bone formation , both diffusely and focally, and, to that limited extent, can be confused with abuse, but in each case, the related signs, symptoms, and radiographic changes provide easy differentiation from abuse. However, both copper deficiency and Menke’s kinky hair syndrome, itself an abnormality of copper metabolism, can be difficult to differentiate from abuse. Radiographic findings include osteopenia, subperiosteal new bone formation, and metaphyseal spurs with fractures indistinguishable from CMLs . Patients may seize and usually manifest psychomotor retardation, although both may not be present in infancy. Wormian bones seen on skull radiographs are usually present and patients usually have sparse depigmented coarse hair . The neurologic features and sparseness of the hair are the main clues to the correct diagnosis. Copper deficiency was advanced by Paterson with reference to TBBD, but no direct clinical or biologic proof was ever submitted . Copper deficiency and Menke’s kinky hair syndrome can be confused with child abuse, but neither bears a sufficient resemblance to the unproven and oft-criticized diagnosis TBBD.
This review was undertaken to describe the current knowledge regarding the radiographic diagnosis of child abuse. The literature review incorporates many articles from the literature combined with information taken from Dr. Paul Kleinman’s authoritative text on abuse to provide the orthopaedic surgeon with the correct information to recognize child abuse . In addition to diagnosing what is child abuse, this review also addresses several disease and normal variants, which, while can be mistaken for abuse, are not in fact abuse. These include normal variant metaphyseal fragmentation commonly seen about the knee, as well as rickets, OI, syphilis, and Menke’s kinky hair syndrome, each of which may be difficult to differentiate from abuse.
Although the entity described as TBBD has been discredited, the controversy regarding nutritional rickets, specifically in breast-fed infants, is an active ongoing debate. The views of Keller and Barnes [28, 29], although largely criticized in the pediatric radiology literature, have not been scientifically disproven. The literature is very limited in the description of normative levels of vitamin D in nursing mothers and their infants, and further investigation is needed. Until then, a close examination of the radiographs is all the more necessary to indicate even mild signs of rickets. However, if no indication of rickets is seen, the films and the injuries recorded on those films should be taken at face value, and if indicative of abuse, whether it be by the finding of a classic MCL, posteromedial rib fracture, or an injury that does not agree with the given history, child abuse should be diagnosed and acted upon.
When suspicion of child abuse is raised, the radiographic investigation focuses on a carefully performed skeletal survey, including frontal images performed of each of the long bones on a separate image, single frontal images of each hand and foot, frontal views of the chest and abdomen, frontal and lateral views of the skull, and lateral views of the spinal column. Oblique views of the ribs are recommended and are very helpful. Each radiograph should be analyzed for findings of abuse, including those fractures that are highly specific for abuse, such as posteromedial rib fractures, CMLs, and scapular, sternal, and spinous process fractures. However, any fracture requires interpretation with respect to the history provided, and even low-specificity injuries, such as long-bone fractures, become very suspicious when a good history is not provided. Further views may be necessary, especially with small fields of view. Followup images and CT scanning are very useful adjuncts.
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