Table 1.
The Graf classification[11]
| Graf type | Angles |
| All type I | Alpha angle > 60 degrees (normal) |
| Type Ia | Beta angle < 55 degrees |
| Type Ib | Beta angle > 55 degrees |
| All type II | |
| Type IIa | Alpha angle 50-59 degrees |
| Type IIb | Alpha angle 50-59 degrees |
| Type IIc | Alpha angle 43-49 degrees |
| Beta angle < 77 degrees | |
| Type D ("about to decenter") | Alpha angle 43-49 degrees |
| Beta angle > 77 degrees | |
| Type III | Alpha angle < 43 degrees |
| Type IIIa and IIIb distinguished on the grounds of structural alteration of the cartilaginous roof | |
| Type IV (dislocated with labrum interposed between femoral head and acetabulum) | Alpha angle < 43 degrees |