NAI : Non-accidental Injury - Andrew Bucknill 29/4/2004
Orthopaedic Manifestations of Child Abuse
Incidence rising but that may be due to improved recognition.
50% of #’s in infants under 1 year are due to abuse.
Risk factors:
Most often under the age of 3 years
Birth weight <2.5kg, first born, premature, handicapped or step children Mother <30 years
Unwanted pregnancy, marital stress, single parent homes, lower social class, cocaine use.
Outcome:
Unrecognized, the mortality rate may be as high as 5 %.
Overall it is 0.1%.
Limb fractures usually heal well without operative intervention.
Diagnosis:
Inconsistencies in story
Late presentation, often to an unknown doctor
Accompanying adult not a parent
Efforts to avoid a full examination
Ix:
Skeletal survey: AP & Lat skull
AP & Lat thoracolumbar spine
AP chest with exposure adjusted to look at bone.
AP extremities to inc shoulders, pelvis, hands and feet
If suspicious and survey normal consider technetium bone scan
Other Ix: FBC, ESR, Urinalysis, Clotting, toxicology
Differential dx:
Osteogenesis imperfecta - in some OI phenotypes, radiographic osteopenia may be slight and may be missed on x-ray. Similarly, blue sclera are far from universal. In these cases, consider dual energy x-ray absorptiometry.
Birth trauma, Rickets, Copper deficiency, congenital syphilis, congenital insensitivity to pain, Caffey’s dis, Vitamin A intoxication, Leukaemia, scurvy
Fracture Patterns:
- rib fractures: the most commonly found fractures in child abuse (followed by humerus, femur, and tibia).
Femur fracture: 80-90% of femur #’s in infants are due to abuse.
Other characteristic features:
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Multiple fractures in various stages of healing
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Spiral #’s require significant rotational force and so more likely to be NAI
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Juxtacortical calcification without #. A result of periosteal separation due to tractional or torsional force on limb. Can resemble osteomyelitis.
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‘Corner’ fracture: ?pathognomonic of NAI. Now thought to be a bucket-handle # of metaphysis seen via a different projection. No gross displacement but corner or chip # is seen (Sub-periosteal bone collar included in distal fragment). 15 to 32% of NAI cases.
Highly specific #’s
: metaphyseal lesions, posterior rib or scapula, spinous process and sternal #’s.
Moderately specific #’s
: multiple #’s, esp bilateral, #’s of different ages, epiphyseal separations, vertebral body #’s and subluxations, digital #’s, complex skull #’s
Low specificity #’s
: clavicular #’s, long bone shaft #’s (except femoral shaft in infants), linear skull #’s.
Good review:
Orthopaedic aspects of child abuse.
KE Cramer.
Pediatric Clinics of
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