Incorporating risk factors in the development of the screening programme for developmental dysplasia of the hips.

In a 12-year cohort study, all newborns with suspected developmental dysplasia of the hips (DDHs) were scheduled for hip ultrasound at the sixth week of life. Female sex is the only isolated risk factor with a positive likelihood ratio predictive of DDH [1.26; 95% confidence interval (CI): 1.04-1.54]. In combination, the presence of two or more risk factors was predictive of DDH (positive likelihood ratio 1.10; 95% CI: 1.00-1.20). The sensitivity and specificity of two or more risk factors for the prediction of DDH were 93.6% (95% CI: 86.6-97.6) and 14.5% (95% CI: 8.70-22.2), respectively. The level of evidence for the cohort study is II.