Arnold-Hilgartner classification is a plain radiograph grading system for hemophilic arthropathy of the knee 1.
Usage
The World Federation of Hemophilia recommends an alternative system, the Pettersson score, for radiographic grading 2.
Classification
stage 0: normal joint
stage I: no skeletal abnormalities, soft-tissue swelling is present
stage II: osteoporosis and overgrowth of the epiphysis, no cysts, no narrowing of the cartilage space
stage III: early subchondral bone cysts, squaring of the patella, widened notch of the distal femur or humerus, preservation of the cartilage space
stage IV: findings of stage III, but more advanced; narrowed cartilage space
stage V: fibrous joint contractures, loss of the joint cartilage space, extensive enlargement of the epiphyses with substantial disorganization of the joint