Risk Factors for Developmental Dysplasia of the Hip Before 3 Months of Age: A Meta-Analysis.

Importance: Two meta-analyses published in 2012 found breech presentation, family history of developmental dysplasia of the hip (DDH), female sex, and primiparity to increase the risk of DDH. However, the DDH definition, reference tests, and the age of the examined children varied considerably, complicating the translation of those findings to current screening guidelines. Objective: To evaluate the association of previously proposed risk factors with the risk of sonography-verified DDH. Data Sources: A literature search strategy used MeSH (Medical Subject Heading) terms and text words associated with DDH and prognostic studies or risk factors. PubMed, Embase, and the Cochrane Library were searched on November 23, 2023, to identify the cohort. Study Selection: Criteria included articles that were in English and published from January 1, 1980, to November 23, 2023. Eligible studies included randomized clinical trials and cohort, case-control, and cross-sectional studies that involved participants younger than 3 months in whom a diagnosis of DDH was made by hip ultrasonography using the criterion standard Graf method, reported information on 1 or more of the proposed risk factors, and reported the final diagnosis. Data Extraction and Synthesis: Collected variables included an evaluated risk factor, the number of infants with a risk factor, the number of infants without risk factors, and the number of infants with and without DDH in the at-risk group and in the no-risk group. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-Analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines. Main Outcomes and Measures: The main outcome measures were risk of DDH (using odds ratios [ORs]) for each of the risk factors. Results: Of 5363 studies screened, 20 studies comprising 64 543 infants were included. Breech presentation (OR, 4.15 [95% CI, 2.62-6.57]), family history of DDH (OR, 3.83 [95% CI, 2.05-7.15]), female sex (OR, 2.50 [95% CI, 1.74-3.59]), oligohydramnios (OR, 3.76 [95% CI, 1.66-8.53]), and high birth weight (OR, 2.00 [95% CI, 1.60-2.49]) were associated with a significant increased risk of DDH. Cesarean delivery, primiparity, multiple births, low birth weight, and prematurity were not associated with DDH risk. Heterogeneity was high (I2 > 70.00%) in all of the tested factors except high birth weight (I2 = 0%). The subgroup analysis was performed to investigate these heterogeneities. Conclusions and Relevance: The findings of this meta-analysis suggest that family history and breech presentation were associated with a significant increase in the risk of sonography-verified DDH in infants younger than 3 months, and a DDH risk increase of female sex was found to be lower than previously reported. A risk increase was detected for oligohydramnios, which has not been included in many screening programs and might also be considered as a referral criterion for hip ultrasonography.