Developmental dysplasia of the hip. Prevention and real incidence.
OBJECTIVE
The controversy over the incidence of developmental dysplasia of the hip (DDH) stems mainly from an ambiguity of criteria for defining a genuinely pathologic neonatal hip. The aim of this study was to identify those neonatal hips which, if left untreated, would develop any kind of dysplasia and, therefore, are to be included in the determination of DDH incidence.


METHODS
Clinical and ultrasonographic examinations for DDH were performed on 4356 neonatal hips. Newborns with skeletal deformities, neurologic/muscular disorders, and neural tube defects were excluded. Hips that featured any type of sonographic pathology were reexamined at 2 or 6 weeks, depending on the severity of the findings. Only hips in which the initial pathology was not improved or had deteriorated were treated; all others were examined periodically until the age of 12 months.


RESULTS
Sonographic screening of 4356 hips detected 301 instances of deviation from normal, indicating a sonographic DDH incidence of 69.5 per 1000. However, only 21 hips remained abnormal and required treatment, indicating a true DDH incidence of 4.8 per 1000 hips. All the others evolved into normal hips, and no additional instances of DDH were found on follow-up throughout the 12 months.


CONCLUSIONS
These findings enables us to distinguish two categories of neonatal hip pathology: one that eventually develops into a normal hip (essentially sonographic DDH); and another that will deteriorate into a hip with some kind of dysplasia, including full dislocation (true DDH). This approach seems to allow for a better-founded definition of DDH, for an appropriate determination of its incidence, for decision-making regarding treatment, and for assessment of the cost-effectiveness of screening programs for the early detection of DDH (Tab. 2, Ref. 15).
Kokavec
M
M
University Department of Paediatric Orthopaedics, Comenius University, Childrens Hospital, Bratislava, Slovakia. kokavecm@hotmail.com
Bialik
V
V
D006618:Hip Dislocation, Congenital / Q000175:diagnosis* / Q000453:epidemiology / Q000517:prevention & control; D006621:Hip Joint / Q000000981:diagnostic imaging; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D015997:Neonatal Screening; D018154:Slovakia / Q000453:epidemiology; D014463:Ultrasonography