Overview
Definition:
Classic metaphyseal lesions, often referred to as "corner fractures" or "bucket handle fractures", are specific radiographic findings in pediatric long bones highly suggestive of non-accidental trauma (child abuse)
They occur at the metaphysis, the wider portion of the bone shaft adjacent to the epiphyseal plate, and represent avulsion of the periosteum and a fragment of trabecular bone during forceful twisting or pulling motion.
Epidemiology:
Metaphyseal lesions are most common in infants and toddlers aged 6 months to 2 years
They are a hallmark sign in about 50% of abusive head injuries and are found in a significant proportion of confirmed cases of physical child abuse
The incidence of identified abusive fractures is difficult to ascertain due to underreporting and diagnostic challenges.
Clinical Significance:
The identification of classic metaphyseal lesions is critical because they are strongly correlated with inflicted injury, differentiating them from accidental falls or birth trauma
Prompt recognition can lead to timely intervention, protection of the child, and appropriate legal and social services involvement
Failure to recognize these signs can result in further harm to the child.
Clinical Presentation
Symptoms:
Infants and young children may present with irritability
Crying, especially when the limb is moved
Lethargy
Poor feeding
Fever
Unexplained bruising or swelling over the affected limb
Sudden onset of pain or inability to bear weight
Sometimes, the child may be asymptomatic and the fracture detected incidentally.
Signs:
Localized tenderness and swelling over the affected bone
Reduced range of motion in the affected limb
Signs of systemic illness if associated with other injuries
In severe cases, neurological deficits may be present due to associated head injury
Examination may reveal palpable crepitus or deformity.
Diagnostic Criteria:
There are no formal diagnostic criteria for metaphyseal lesions themselves, but their presence on imaging, particularly in the context of a suspicious history or lack of credible explanation for trauma, constitutes a strong indicator of abuse
Radiographic interpretation focusing on the characteristic appearance and location is paramount.
Diagnostic Approach
History Taking:
Detailed history regarding the mechanism of injury is crucial
Inquire about who was present, the exact circumstances of the fall or injury, and the child's behavior before and after
Look for inconsistencies in the provided history, vague explanations, or a history that does not correlate with the radiographic findings
Ask about prior injuries or concerning behaviors from caregivers.
Physical Examination:
A thorough head-to-toe physical examination is essential
Palpate all long bones for tenderness, swelling, or deformity
Assess range of motion of all joints
Examine the skin for any bruises, lacerations, or burns, noting their location, color, and pattern
Look for evidence of retinal hemorrhages or other signs of abusive head trauma.
Investigations:
Skeletal survey (full-body X-rays) is the cornerstone investigation for suspected child abuse, including suspected metaphyseal lesions
This survey includes anteroposterior (AP) and lateral views of the skull, spine, pelvis, and all extremities
Specific views focusing on the metaphyses of long bones are critical
Ultrasound may be used for initial assessment of soft tissue swelling
CT or MRI may be necessary for more detailed evaluation of complex fractures or associated injuries
Blood tests like complete blood count (CBC), coagulation profile, and calcium/phosphate levels are important to rule out metabolic bone disease and assess for occult bleeding.
Differential Diagnosis:
Metabolic bone diseases such as rickets and osteogenesis imperfecta
Osteomyelitis
Birth trauma
Accidental fractures (e.g., toddler's fracture, accidental fall)
Osteoporosis in children with chronic illness
Benign bone tumors
Fragile X syndrome can sometimes present with fractures but typically not classic metaphyseal lesions.
Management
Initial Management:
Immediate priority is the child's safety and medical stabilization
The child should be removed from the abusive environment and placed under protective care
Pain management is essential, often with analgesics
Any immediate life-threatening injuries must be addressed.
Medical Management:
There is no specific medical management for the fracture itself, other than pain control
Management focuses on addressing the consequences of abuse
Collaboration with child protective services and social workers is paramount
Psychiatric evaluation of the caregivers may be necessary.
Surgical Management:
Operative management is indicated for displaced fractures, unstable fractures, or those causing significant pain or functional impairment
Surgical techniques may include closed reduction and casting, or open reduction and internal fixation (ORIF) with plates, screws, or intramedullary nails, depending on the fracture pattern and location.
Supportive Care:
Supportive care includes vigilant monitoring for pain, signs of infection, and complications
Nutritional support is important, especially for malnourished children
Physiotherapy and occupational therapy are vital for rehabilitation and restoring limb function post-fracture
Psychological support for the child and siblings is also crucial.
Complications
Early Complications:
Malunion or nonunion of the fracture
Compartment syndrome
Infection (osteomyelitis)
Nerve or vascular injury
Hemorrhage
Acute pain and distress
Systemic inflammatory response syndrome (SIRS).
Late Complications:
Chronic pain
Joint stiffness and deformity
Limb length discrepancies
Post-traumatic arthritis
Psychological sequelae, including PTSD and behavioral issues
Developmental delays
Re-abuse or neglect.
Prevention Strategies:
Early identification and reporting of suspected abuse
Public awareness campaigns on child safety
Support systems for at-risk families
Comprehensive medical and social work intervention upon suspicion of abuse
Consistent and thorough skeletal surveys in at-risk children.
Prognosis
Factors Affecting Prognosis:
The severity and number of injuries
The age of the child
The presence of associated head or internal injuries
The timeliness and effectiveness of intervention
The stability of the home environment post-intervention
The presence of underlying medical conditions that may affect healing.
Outcomes:
Outcomes vary widely
Some children may have a good recovery with minimal long-term physical sequelae
However, many children suffer permanent physical and psychological damage
The risk of further abuse and fatality remains significant if protective measures are not robust
Early and comprehensive intervention improves outcomes.
Follow Up:
Long-term follow-up is essential to monitor for physical complications such as malunion, growth disturbances, and secondary arthritis
Regular clinical assessment and imaging may be required
Psychological and developmental follow-up is critical to address the long-term impact of trauma and abuse
Ongoing assessment of the child's safety and well-being within the family environment is paramount.
Key Points
Exam Focus:
Classic metaphyseal lesions are highly specific for non-accidental trauma
They represent avulsion of periosteum and metaphyseal bone
Most common in infants/toddlers (6 months - 2 years)
Always consider a skeletal survey in suspected child abuse
Skeletal survey protocol includes AP and lateral views of all long bones, skull, spine, and pelvis.
Clinical Pearls:
The history of injury must correlate with the radiographic findings
A "fall from standing height" is unlikely to cause a metaphyseal lesion
Inconsistencies in the caregiver's story are a significant red flag
Even subtle metaphyseal lucencies should be considered abusive until proven otherwise
Differentiate from osteogenesis imperfecta, rickets, and osteomyelitis.
Common Mistakes:
Dismissing the injury as accidental without a thorough skeletal survey
Failing to consider abuse in the differential diagnosis
Inadequate history taking regarding the mechanism of injury
Not obtaining adequate imaging (e.g., missing views in a skeletal survey)
Misinterpreting healing fractures as new injuries or vice versa.