A 15 year prospective, observational cohort study was undertaken to assess selective screening of DDH in males and females referred with risk factors only.

Individuals born breech or with evidence of a strong family history for DDH were the ‘risk factors’ studied. All were clinically examined and sonographically screened by one Consultant Paediatric Orthopaedic surgeon. Irreducible hip dislocation rate was the primary outcome measure.

From a cohort of 64670 live births, 2,984 neonates/infants, 46.1 per 1000 live births [95% CI 44.6 to 47.8 per 1000 live births] were referred and sonographically screened with ‘pure’ risk factors of breech presentation and/or family history, with clinical stability. 1360 were male, of which 4 were identified as having ‘pathological’ DDH; an incidence of 1 in 333 of those males referred [95 CI 0.001, 0.008]. 1624 were female, of which 45 were identified as having ‘pathological’ DDH; an incidence of 1 in 36 of those females referred [95% CI 0.021, 0.037]. There was a significant difference in the number of female individuals sonographically diagnosed as having ‘pathological’ DDH compared to males (p<0.001). Four individuals were diagnosed with irreducible hip dislocation, 0.06 per 1000 live births [95% CI 0.24, 0.159 per 1000 live births]. All were in females. Additionally, there were 2 female individuals; both with family history of DDH (1^st cousin splinted and sister splinted, respectively) as a risk factor, referred late.

Our study suggests that there is a significant difference between the incidence of female and male individuals diagnosed with ‘pathological’ DDH, in those referred purely with risk factors (breech and family history). These findings question the current screening policy for ultrasound examination of males with risk factors in the absence of clinical instability, and may influence future DDH screening programme policy.

Level of evidence: II