an mri is the best way to spot it.
Symptoms are a burning constant dull pain at the back of the pelvis, and no painkillers can take more than just the top
It shows as 2 white triangular areas in the illiac bone. The joint itself is unaffected. Bloodsamples will be normal with no sign of infection. PT/light stretching/massage will not help since oci is only inside the bone, and you cannot stretch or massage the inside of a bone.