"stage 0: prenecrotic"
"stage I: normal radiograph, osteonecrosis noticeable on MRI or bone scan"
"stage II: lunate sclerosis"
"IIIA: lunate collapse, radioscaphoid angle"
"IIIB: lunate collapse and carpal instability, radioscaphoid angle >60º"
"IIIC: chronic coronal lunate fracture"
"stage IV: carpal collapse and perilunate arthrosis (Kienböck disease advanced collapse)"