Comparison of clinical and sonographic prevalence of developmental dysplasia of the hip.

Developmental dysplasia of the hip (DDH) is one of the most widely discussed abnormalities in neonates. The advantages of sonographic examination are well known, but its main disadvantage is that it might lead to over diagnosis, which might cause over treatment. Variations in the incidence of developmental dysplasia of the hip are well known. During six months study since September 2006 all 1300 neonates (2600 hips) were born in our hospital examined clinically and sonographically (587 hips) in the first 48 hours of life. Sonography was performed according to Graf's method, which considers mild hip sonographic abnormalities as type II a. Type IIb Graf were considered pathologic. Sonography screening of 587 hips detected 36 instances of deviation from normal indicating a sonographic DDH incidence of 12.5%. However, only 8 neonates remained abnormal and required treatment, indicating a true DDH incidence of 6 per 1000 live birth. Risk of diagnosis clinically and sonographicaly were 2.5 and 4.5 percent respectively and was significant (P<0.00001, x(2)=1170). In order to avoid over diagnosis in first days examination, repeated clinical and sonographic examination is required.