[Evaluation of screening for developmental dysplasia of the hip in the Liberec region in 1984-2005].

PURPOSE OF THE STUDY To analyze our results of screening for developmental dysplasia of the hip (DDH) in the Liberec region between 1984 and 2005 MATERIAL AND METHODS The study comprised 30,010 infants screened for DDH without any primary selection between 1984 and 2005.The infants were clinically examined on the basis of a three-step screening system (newborn, at 6 weeks and between 3 and 4 months of age) and by an imaging method. In the period from 1984 to 1991, this was plain radiography of the hip at 3 months of age, and a total of 12,944 infants were assessed. Between 1992 to 2005 ultrasonography (USG) was used at 6 weeks (or earlier when clinical signs were present) and again at 3 to 4 months of age, and a total of 17,066 infants were evaluated. In 16,678 of these infants, the sonogram obtained at 6 weeks was evaluated in detail by the Graf method. The presence of the epiphyseal nucleus of the proximal femur was assessed at 3 months, and from 2000 at 4 months of age. Attention was paid to the occurrence of DDH in general and findings of dislocation, both subluxation and luxation, of the hip, the proportion of right-side, left-side and bilateral findings, gender differences, the presence or absence of ossification of the femoral epiphyseal nucleus in infants between 3 and 4 months of age and, in the 1992-2005 period, the stratification of Graf types at 6 weeks. A question of whether the child's months of birth might have any relation to a possibility of DDH occurrence was also raised. RESULTS Between 1984 and 1991, DDH was recorded in 10.4% of the infants, usually in a light form responding well to conservative treatment; subluxation was found in 1.99% and luxation in 0.6%. Between 1992 and 2005, DDH (mostly light forms) was recorded in 5.2%, subluxation in 0.5% and luxation in 0.2% of the infants. Right-side, left-side and bilateral findings were seen in 29%, 46% and 25% of the infants, respectively, and there were distinct differences between the genders. In an evaluated group of 453 infants with either subluxation or luxation, 86% of girls and 14% of boys were affected. The month of birth had no effect on DDH occurrence. Of the 9878 infants examined at 3 months, ossification of the femoral epiphyseal nucleus was found only in 37%, and of the 7188 infants examined at 4 months this was recorded in 64%. In a total of 33,356 hips (16,678 infants) evaluated at 6 weeks on the Graf scale, the following Graf types were recorded: Ia, 21%; Ib, 58%; IIa, 20%; IIc, 1%; D/IIIa, 0.19%; and IIIb/IV, 0.08%. DISCUSSION The occurrence of DDH (formerly congenital dysplasia of the hip), including all forms/grades, is reported to be 3% to 5% in Central Europe. Our recent results obtained by the USG method are in agreement with this, as are our findings of its more frequent occurrence in girls (boys to girls, 1 to 6) and on the left side. Several reasons--medical, statistical or even sociodemographic--can be considered to explain the discrepancies in DDH detection rates obtained with radiography and ultrasonography, i.e., 10.5% vs 5.3%. For instance, the USG detection of DDH at 6 weeks of age initiates early treatment preventing progression of hip dysplasia. Better facilities available for home neonatal care and increased interest in general baby wellness may also play a role. CONCLUSIONS Screening for developmental dysplasia of the hip is fully justified, because DDH prevalence is still high (500 subluxations and 200 luxations per 100,000 population). However, attention should also be paid to reducing factors and conditions that may adversely affect hip development from the baby's prenatal period to spontaneous walking.