Developmental Dysplasia of the Hip in Infants: Prevalence and Risk Factors

Background and Objectives: Developmental dysplasia of the hip (DDH) is an orthopedic condition in the pediatric population, affecting between 0.1% and 3% of infants. Chile has one of the highest incidences in South America, reaching 1 per 500 live births. Given the potential of adverse consequences of DDH on infant health, preliminary studies are needed to determine its prevalence in the population and assess its association with relevant risk factors. Materials and Methods: The study is single-center, conducted in a Chilean population. The sample size calculation determined the use of 100 pelvic radiographs, considering a 95% confidence level and a proportion of 0.5. The infants were between 90 and 150 days old. Information was collected on possible DDH-related risk factors. For the analysis, normality tests, Chi-square tests, independent samples t-tests, Mann-Whitney U tests, and multivariate analyses were applied. Results: The prevalence of DDH was determined to be 12%, affecting the left hip to a greater extent. Female infants had a higher frequency of DDH. A statistically significant association was found between the prevalence of DDH and the presence of asymmetry in the abduction of the hip joint (p = 0.023), acetabular roof obliquity (p = 0.003), left hip involvement (p = 0.002), and height at two months of age (p = 0.016). Conclusions: The prevalence of DDH in infants was higher than that reported in the literature. However, with regard to sex, the data coincide with those previously reported by other authors.