DEVELOPMENTAL DYSPLASIA OF THE HIP IN SOUTH-AUSTRALIA IN 1991 - PREVALENCE AND RISK-FACTORS

Objectives: To determine the prevalence of developmental dysplasia of the hip (DDH) in South Australia (SA) in 1991, the proportion of cases detected in the neonatal period and the perinatal risk factors for DD H. Methodology: Cases of DDH born in SA in 1991 were identified from m ultiple sources and their clinical data linked to perinatal data provi ded by midwives; five controls per case were obtained randomly from SA livebirths without congenital abnormalities and adjusted odds ratios (OR) for potential risk factors obtained by logistic regression analys is. South Australia perinatal data were also used to estimate numbers of births with perinatal risk factors for targeted screening. Results: Two hundred and six cases of isolated DDH were identified, giving a p revalence of 10.5 per 1000 births. Or these, 173 (84%) had been detect ed in the neonatal period. The perinatal risk factors for DDH were ide ntified as breech presentation (OR 9.65), female babies (OR 4.04), fir st births (OR 1.91) and maternal age of 25 years or more (OR 1.53). Sc reening breech and firstborn female babies (23% of births) would yield approximately 51% of cases of DDH. Conclusions: Isolated DDH had a pr evalence of 10.5 per 1000 births and 84% of cases had been detected in the neonatal period in SA. Repeated screening during infancy of 'at r isk' groups of babies is recommended.