The essential role of ultrasound examinations in diagnosis and treatment of developmental dysplasia of the hip (DDH) is widely accepted while the weighting and correlation of protective factors and perinatal risk for DDH still give rise to debate. Our aim was to investigate the impact of single and twofold combined risk and protective factors on the newborns' hip maturity, assessed with the Graf ultrasound method. Therefore, data sets of 11,820 universally screened newborns were analyzed. Univariate and logistic regression analyses were performed to correlate risk and protective factors with mature or immature but appropriate for age and pathologic hip types. Thereby, female gender (OR 4.07 (95% CI 3.01-5.51), p < 0.001), breech presentation (4.98 (3.71-6.71), p < 0.001), and positive family anamnesis (5.05 (3.49-7.31), p < 0.001) as well as the combination of female gender with high birth weight (3.51 (2.45-5.03), p < 0.001) could be identified as independent predictive risk factors. Only low birth weight (0.27 (0.11-0.66), p = 0.004) could be identified as a single protective factor, while no combination of protective factors was significant.
Conclusion: The significance and the informative value of risk and protective factor combinations, e.g., for selective ultrasound surveys, are limited. Early universal ultrasound screening using the Graf method is advised to timely detect hip immaturity and pathologies and to provide the optimal approach for mature or immature but appropriate for age and pathologic hips. What is Known: • Ultrasound screening is essential for diagnosis and treatment of DDH in time while the weighting and correlation of protective factors and perinatal risk and their role for the ultrasound screening protocol still give rise to debate. What is New: • The effects of single risk and protective factors for DDH do not cumulate or counteract, resulting in a limited value of a selective screening protocol based on risk and protective factors. • A universal screening protocol using the Graf ultrasound method is recommended.
Keywords: Congenital; Hip dislocation; Odds ratio; Regression analysis; Sonographic neonatal screening.