The Epidemiology and Demographics of Hip Dysplasia

Table 1

Graf’s classification of hip dysplasia using ultrasound.

Graf’s hip type	Description	α angle (°)	β angle (°)	Age
I	Normal	>60	<55	Any
IIa	Physiologically immature	50–60	55–77	0–12 wks
IIb	Immature	50–59	55–77	>12 wks
IIc	Acetabular deficiency	43–49	>77	Any
IId	Everted labrum with subluxation	43–49	>77	Any
III	Everted labrum with dislocation	<43	>77	Any
IV	Dislocation	<43	>77	Any

As described by Graf [23], Roposch et al. [24], and Herring [25].