The Risk of Developmental Dysplasia of the Hip (DDH) in High Birth Weight babies: A Major Risk Factor Detected in the Analyses of Sonograms based on the Graf Technique

The purpose of this retrospective study was to check sonographic hip types according to the Graf technique and to compare the results related to large newborns with those related to the normal and small ones based on their Gestational Age (GA); and to investigate the influence of birth weight on the incidence of Developmental Dysplasia of the Hip (DDH).
Between 1993 and 2003 Ultrasonography (US) of the hips was performed in 7417 consecutive newborns at 34-42 gestational weeks using the Graf method during the first week of life.
The US showed pathological findings in 168 hips (2.3%). 139 of these cases were girls (82.7%) and 29 were boys (17.3%). According to Graf types, there were 63 type IIc, 56 type D, 46 type III, and 3 type IV hips. Except for one boy (type III) all were successfully treated by conservative orthopedic methods. Being overweight (large for GA) in association with breech presentation showed the highest risk for pathological hips requiring treatment (15.6%), followed by normal weight and breech presentation (7.6%), and then came the term newborns large for GA (5%). The lowest percentage need of subsequent orthopedic treatment was in 66 in small newborns for GA with breech presentation (1.5%). There were no associations with DDH in 230 small GA newborns at term, and in 174 twins.
The results, according to the sonographic types, suggest that high birth weight is a major risk factor of DDH, especially when combined with breech presentation; and an almost 5:1 female preponderance was observed.