The signs and symptoms. They will have a prolonged limp. They will have a waddle. They will have pain in the groin, thigh or knee. You want to note how delayed they are because that will impact on their prognosis.
Bone scans can be helpful early.
MRIs, I generally don t get because they just confuse you. You can see this little wafer of bone used to be one of those nice balls of femoral head and it just collapsed and he has got changes down here in his metaphysis. The more the lateral column out here is involved, the worse the prognosis. The prognosis is also worse if the onset of the disease is after the age of 6. Or the prognosis, I should say, is better if it is before the age of 6.