Risk Factors for Developmental Dysplasia of the Hip: A Critical Analysis About an Unclear Relationship

Objective: To evaluate the relationship between prenatal risk factors and developmental dysplasia of the hip using the Graf grade, and to identify the determinants of a higher Graf grade. Materials and Methods: A retrospective analysis of data from 112 newborns with DDH was conducted. The participants were selected on the basis of a DDH diagnosis using sonography. A total of 181 hips of patients with DDH were considered in our study group (Graf types IIa to IV), and the normal hips of those affected unilaterally were excluded from the analyses (43 participants were affected unilaterally). The risk factors considered included female sex, breech presentation, firstborn status, familiarity, association with other orthopedic abnormalities, and uterine packing, which includes factors such as twin pregnancy, macrosomia, and oligohydramnios. Binary logistic regression was used to analyze the relationship between these variables and the Graf type of DDH at presentation, which was defined using two groups: Graf types IIc-IV, which include unstable or decentered hips, and Graf types IIa and IIb, which encompass stable and centered hips. Results: The analyses revealed a significant protective role of the presence of other lower limb congenital malformations such as clubfoot, which was more closely associated with a stable form of DDH (OR = 0.26, p = 0.017), a significant association between the presence of mechanical risk factors in females with an unstable form of DDH (OR = 5.00, p = 0.042), a borderline significant protective role of breech presentation in females, which was more closely associated with a stable form of DDH (OR = 0.25, p = 0.054), and a borderline significant association between the presence of mechanical risk factors and an unstable form of DDH (OR = 4.28, p = 0.054). Conclusions: Prenatal risk factors may have a complex effect on the Graf grade in DDH. The protective effects of some factors in contrast with the increased risk associated with other factors suggest a possible relationship, with some prenatal risk factors affecting the severity of DDH. These findings may have implications for the early identification and management of DDH.