Evaluation of the clicky hip as a screening tool in the diagnosis of developmental dysplasia of the hip.

AIMS: The early diagnosis of developmental dysplasia of the hip (DDH) is important because treatment in early infancy is usually nonoperative. A consensus statement from the British Society for Children's Orthopaedic Surgery identified ongoing uncertainty regarding the predictive value of a documented clicky hip. The aim of this study was to evaluate the association between a clicky hip at the newborn or six- to eight-week examination and pathological DDH requiring treatment in a selective screening programme in the UK.

METHODS: This was a retrospective analysis of prospectively collected registry data for all live births in the catchment area of a single tertiary centre between January 2016 and December 2023. Infants underwent examination at birth and again at six to eight weeks, with ultrasound screening offered for those with primary risk factors or abnormal findings on examination, including a clicky hip. The primary outcome was pathological DDH requiring treatment. Multivariable logistic regression was used to estimate the adjusted odds ratios (ORs) for DDH. Positive predictive value (PPV), risk difference (RD), and the number needed to screen (NNS) were calculated as programme-level measures.

RESULTS: Of 42,338 infants who were analyzed, 7,564 (17.9%) underwent ultrasound screening. Pathological DDH requiring treatment was identified in 245 (5.8 per 1,000 live births). A clicky hip was recorded in 1,125 infants, of whom 40 (3.56%) had DDH requiring treatment. Clicky hip was independently associated with DDH (adjusted OR 4.68 (95% CI 3.11 to 7.03); p < 0.001). Within the selective screening pathway, the RD was 3.86% (95% CI 2.65 to 5.07), the PPV was 3.56% and the NNS was 26.

CONCLUSION: In this large UK cohort within a selective screening programme, a clicky hip was independently associated with DDH requiring treatment. Although limited by differential ascertainment inherent to selective screening, these findings support the prospective evaluation of an isolated documented clicky hip as an indication for referral in selective screening pathways for DDH.