Universal Clinical DDH Screening Complemented with Targeted Ultrasound Is Effective in Finland.

Background: The late diagnosis rate of developmental dysplasia of the hip (DDH) with universal ultrasound screening is 0.2 per 1,000 children according to a recent meta-analysis, which is the same as in Japan where selective ultrasound screening is used. We hypothesized that Finland's current program of universal clinical screening complemented with targeted ultrasound is noninferior to universal and selective ultrasound screening programs.

Methods: For this retrospective cohort study, we collected the number of children <15 years of age who were diagnosed with DDH (International Classification of Diseases, Tenth Revision [ICD-10] codes Q65.0-Q65.6 and Ninth Revision [ICD-9] code 7543) as their primary diagnosis after ≥3 visits to a physician. These data were obtained from the Finnish Care Register for Health Care, which collects the ICD-10 and ICD-9 codes from every medical appointment. We calculated the annual incidence of DDH diagnoses per 1,000 newborns between 2002 and 2021. Late diagnosis of DDH was defined as a finding of DDH in children aged 6 months through <15 years at the initial diagnosis who had undergone treatment under anesthesia (closed reduction and casting or surgery). We also registered the geographic, age, and sex distributions of the DDH diagnoses.

Results: During the 20-year study period, 1,103,269 babies were born (median per year, 57,214 babies; range per year, 45,346 to 60,694 babies). A total of 6,421 children had a diagnosis of DDH (mean per year, 321 children; range per year, 193 to 405 children), with a mean calculated incidence of 5.8 per 1,000 newborns (95% confidence interval [CI], 5.7 to 6.0). Altogether, 120 children aged 6 months through <15 years were treated for DDH, with little annual variation (median, 6.5 children; range, 2 to 9 children). The mean national incidence of late-diagnosed cases was 0.11 per 1,000 newborns (95% CI, 0.09 to 0.13).

Conclusions: Finland's current DDH screening program, which includes universal clinical screening with targeted ultrasound, is noninferior when compared with other screening programs.

Level of evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.