Graf angles in developmental dysplasia of hip

TypeAlpha angleBeta angleBony roofOssific rimCartilage roofInterpretation
I a >60<55good sharpcovers femoral headmature
I b>60>55good usually bluntcovers headmature
II a 50-59>55deficientroundedcovers head< 3 months of age (physiological ossification delay)
II b50-59>55deficient roundedcovers head> 3 months of age
II c43-49<77deficientrounded/flatcovers head
II d43-49>77severely deficientrounded/flatcompressed on point of dislocation
III a<43>77poor flatdisplaced up echo poordislocated
III b<43>77poor flat displaced up reflectivedislocated
IV<43>77poor flat interposeddislocated