Prevalence of Acetabular Dysplasia in Early Adolescents From the General Population: A Generation R Study.

BACKGROUND: Acetabular dysplasia is an important risk factor for hip complaints and osteoarthritis in (young) adults. Early identification during childhood is important, as timely intervention may prevent irreversible joint damage. Although traditionally considered an infant-onset condition, more recent evidence indicates that acetabular dysplasia can also develop later in childhood, yet its occurrence rate remains unknown. Existing prevalence estimates derive mainly from infants, adults, or selected clinical samples.This study aims to determine the prevalence and distribution of acetabular dysplasia in a large, multiethnic cohort of early adolescents, including key subgroup analyses.

METHODS: This study was part of the Generation R study, an ongoing prospective population-based cohort study in Rotterdam (NL). In early adolescence, DXA imaging of the right hip was done, and the lateral center-edge angle (LCEA), as an indicator for acetabular roof coverage, was determined. Acetabular dysplasia was defined as LCEA <20.0 degrees. Prevalence was estimated and reported as a percentage with 95% CI in the overall population and subgroups.

RESULTS: A total of 3896 participants were included with a mean age of 13.6 years (SD: 0.3 y) and 46.8% males. Overall prevalence of acetabular dysplasia was 6.4% (95% CI: 5.6-7.1). In multivariate analysis, sex assigned at birth and ethnicity had no statistical significant association with acetabular dysplasia, but prevalence was higher in skeletally immature compared with skeletally mature participants (OR=2.94).

CONCLUSION: The prevalence of acetabular dysplasia was 6.4%. Skeletal immaturity was strongly associated with acetabular dysplasia. This prevalence is higher than in infants and comparable to adults, which suggests that acetabular dysplasia can develop later during childhood growth.

LEVEL OF EVIDENCE: Level II.