imaging

Last reviewed 01/2018

As a rule, radiographic changes in Perthe's disease are usually firmly established before symptoms develop although few changes are apparent in very early disease (1):

  • collapse
  • sclerosis - due to reduced resorption and relative osteopaenia of the rest of the bone
  • subchondral fractures as the earliest sign of collapse
  • increased joint space
  • femoral head ossification centre is smaller on the affected side and can appear fragmented
  • coxa magna - spherical enlargement of the femoral head probably due to increased vascularity

Waldenström has divided radiological stages which all children with Perthes disease pass through into initial, condensation, fragmentation, repair, and healing stages (1)

MRI can detect avascular areas before there is collapse. MRI is therefore indicated in cases of recurrent irritable hip (3).

Bone scans are useful in early disease when diagnosis can be prompted by demonstration of decreased uptake in the avascular phase and increased uptake in the healing phase.

Reference: