The reliability of Graf's technique in diagnosing developmental dysplasia o
f the hip (DDH) is investigated in this report. In a prospective study, 6,5
48 neonates were examined clinically and sonographically; 470 children were
reexamined at least once. Sonographic alpha angles and radiographic acetab
ular index (AI) angles were followed up and compared. Results were as follo
ws: 84.6% of the hips were mature; 14.3% were physiologically immature; 1.1
% were dysplastic. Of the sonographically dysplastic hips, 63% were clinica
lly normal. Neonatal sonographic hip status was affected by family history,
breech delivery, birth weight, and gestational age. At follow-up, none of
the primarily mature hips had worsened. Of the type IIa hips, 89% matured s
pontaneously, and 11% needed abduction. The 68 dysplastic hips had matured
after a maximum of 80 days' abduction, with normal alpha and AI angles by t
he end of treatment. At 1 year, the pitch had deteriorated again in six chi
ldren. Graf's sonographic technique reliably diagnoses infantile DDH. Regul
ar orthopedic checkups are needed to detect secondary deterioration of dysp
lastic hips.