UCSD Musculoskeletal Radiology bonepit.com MSK Classifications

Grade 0.    Seen on MRI or NM, normal plain film-asymptomatic

Grade 1.    Seen on MRI or NM, normal plain film-symptomatic

Grade 2.    Mixed sclerosis and lucency on plain films, no collapse

Grade 3.     Cresentic collapse on plain films

Grade 4.    More significant collapse of femoral head

Grade 5.    Secondary OA of acetabulum

The combined necrotic angle of Kerboul

Only useful in stage 2 or less AVN to predict chance of collapse.

Add the necrotic angle of AVN on the coronal and sagittal images.

Less than 150º good prognosis - may spontaneously heal

Between 150º and 250º intermediate prognosis

Greater than 250º poor prognosis - will go on to collapse