A Systematic Review and Meta-analysis on the Reproducibility of Ultrasound-based Metrics for Assessing Developmental Dysplasia of the Hip

BACKGROUND:The purposes of this study were to (1) perform a systematic review of articles that reported agreement or reproducibility in repeated diagnosis of developmental dysplasia of the hip (DDH) using ultrasound imaging, (2) estimate the reproducibility in the available dysplasia metrics, and (3) compare reproducibility of the available dysplasia metrics. METHODS:A systematic review of the Medline and Embase databases was performed by using a search strategy formulated from our research question“For infants at risk of DDH, are US imaging-based diagnoses reproducible?” Two reviewers independently identified articles for inclusion in the systematic review, and then assessed the quality of the included studies using the Guidelines for Reporting Reliability and Agreement Studies guideline. Variability and agreement-related statistics in the included studies were extracted and included in a meta-analysis for summarizing the available statistics. The reproducibility of the available dysplasia metrics was compared, with a Bonferroni correction made to adjust for multiple comparisons. RESULTS:Twenty eight studies were included in the systematic review. Overall, the quality of the included studies was moderate (average, 10.7/15; range, 6 to 12). Graf’s alpha angle had the lowest interexamination variability of the metrics assessed, followed by Graf’s beta angle (the variability of the alpha angle was 10% lower than the variability of the beta angle, P