UCSD Musculoskeletal Radiology

bonepit.com

MSK Classifications

 

AVN grading system

Steinberg modification of the Arlet and Ficat system

 

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 150 good prognosis - may spontaneously heal

Between 150 and 250 intermediate prognosis

Greater than 250 poor prognosis - will go on to collapse