Plain radiographs of the hip (bilateral AP and frog-leg views)
Widened physis (early finding)
Displacement of<unk>  neck to head (late finding, so called 'ice cream cone' sign)
May show necrosis of the<unk>  head in late cases complicated by avascular necrosis
Note that up to 40% of patients will have bilateral involvement 
Klein's line
Line from superior cortex of<unk>  neck parallel to greater trochanter
Normally should cross through 1/3 of<unk>  head
If does not cross the<unk>  head, highly suspicious for<unk> 
May require MRI in ambiguous cases
Widened physis (early finding)
Displacement of<unk>  neck to head (late finding, so called 'ice cream cone' sign)
May show necrosis of the<unk>  head in late cases complicated by avascular necrosis
Note that up to 40% of patients will have bilateral involvement 
Line from superior cortex of<unk>  neck parallel to greater trochanter
Normally should cross through 1/3 of<unk>  head
If does not cross the<unk>  head, highly suspicious for<unk> 
If does not cross the<unk>  head, highly suspicious for<unk>
Slipped capital femoral epiphysis
Acute rheumatic fever
Interphalangeal dislocation 
Developmental dysplasia of hip
Lens dislocation
Femur fracture
Calcaneus fracture
Juvenile idiopathic arthritis