disease is idiopathic avascular necrosis of the femoral head. It occurs
most commonly in children between the ages of 5-8 who present with knee
or hip pain or a limp. Boys are more commonly affected than girls (5:1).
The disease is bilateral in approximately 15% of cases. A
good prognostic indicator in Legg-Calve-Perthes disease is the age of
onset because if it occurs by age six, then restoration
of the spherical femoral head is likely and degenerative osteoarthrits can be
- widening of the
joint space: secondary to effusion or hypertrophic synovium
- crescent sign: subchondral
linear lucency representing a fracture through necrotic bone (best seen
on frogleg view)
- MRI: high-signal
marrow edema on T2WI
- bone scan: decreased
activity in the capital femoral epiphysis early and increased activity during healing
- fragmentation and/or
collapse of the femoral epiphysis with areas of increased sclerosis
- coxa magna = broad overgrown femoral head
- coxa plana = flat
- short femoral neck
- arrest of physeal
disease in a 6-year-old boy. AP pelvic radiograph shows irregularity
in contour of the right femoral head and widening of the right joint
space as compared with the normal findings on the left.
disease in a 6-year-old boy.Coned-down frogleg view of the right hip
shows a crescentic subchondral lucency consistent with a fracture through necrotic bone.
disease in a 6-year-old boy. Coned-down AP view of the right hip demonstrates
the progression of this disease. Note how the femoral head has become
markedly flattened (coxa plana) and enlarged (coxa magna).
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