Tab. 1.

Graf classification scale for developmental dysplasia of the hip

Type	Alpha angle	Acetabular modelling	Bony acetabular rim	Beta angle	Labrum	Position of femoral head	Age
1A	>60°	good	sharp	<55°	good femoral coverage	central	all
1B	>60°	good	slightly rounded	<55°	good femoral coverage	central	all
2A	50–59°	deficient	rounded	<55°	coverage femoral head	central	<3 mo
2B	50–59°	deficient	rounded	<55°	coverage femoral head	central	>3 mo
2C	43–49°	severely deficient	rounded/flat	>55 but <77°	still coverage femoral head	stable or unstable	all
D	43–49°	severely deficient	rounded/flat	>77°	still coverage femoral head	decentering	all
3	<43°	poor	flat		labrum pressed upwards	eccentric	all
4	<43°	poor	flat		labrum pressed downwards/disappears	eccentric	all