Objective: To determine the effectiveness of ultrasound screening for developmental dysplasia of the hip (DDH) after the neonatal period. Design: Prospective cohort study. Setting: Child health care centres. Participants: Infants attending the child health care centres. Interventions: The intervention group (n = 5170) was screened by ultrasound at 1, 2, and 3 months of age. The control group (n = 2066) was screened by routine physical examination as part of the programme for child health surveillance at the child health care centres (CHC screening). For evaluation of the screening, the children in both the intervention and control group received an ultrasound examination after 6 months of age to detect any abnormality that might have been missed by the screening. Results: The sensitivity of the ultrasound screening was 88.5%, and the referral rate 7.6%. As a result of the ultrasound screening, 4.6% of the children were treated. The sensitivity of the CHC screening was 76.4%, with a referral rate of 19.2%. The treatment rate was 2.7%. Of the treated children in the ultrasound screening group, 67% were referred before the age of 13 weeks, whereas in the CHC screening group only 29% were referred before this age. Conclusions: This study shows that ultrasound screening detects more children with DDH than CHC screening and that more of them are detected at an earlier age. To accomplish this, even fewer children have to be referred. However, even general ultrasound screening seems not to eradicate late cases of DDH. The higher treatment rate in the population screened by ultrasound may be a result of overtreatment.

The natural history of sonographic developmental dysplasia of the hip was determined in a population-based study in which 5170 infants were screened by ultrasound using Graf's method. Of the normal hips at the age of 1 month, 99.6% were still normal at the age of 3 months. Of the immature type IIa/IIa+ and type IIa- hips, if untreated, 95.3 and 84.4% had become normal, respectively. Of the infants with type IIc, D and III/IV hips at the age of 1 month 70, 58.3 and 90.9% were treated, respectively. This study shows that normal hips remain normal in nearly 100% of cases, but development to abnormality is possible. It shows also that most of the immature hips at the age of 1 month become normal without treatment. Although treatment seems to be indicated in the majority of sonographically abnormal hips, the occurrence of overtreatment could not be excluded in our study.

OBJECTIVES: This study evaluated the validity of the traditionally recommended screening protocol for developmental dysplasia of the hip in infants. METHODS: Study children (n = 1968) underwent a standardized screening examination. RESULTS: The incidence of developmental dysplasia of the hip was 3.7%. The sensitivity of the test protocol was 86%, the specificity was 82%, and the predictive values of positive and negative tests were 16% and 99%, respectively. CONCLUSIONS: The validity of the screening protocol for developmental dysplasia of the hip is disappointingly low. The yield of adding an ultrasonographic examination to current screening activities needs further study.