Should all twins and multiple births undergo ultrasound examination for developmental dysplasia of the hip?: A retrospective study of 990 multiple births.

Twins are often considered to be at an increased risk of developmental dysplasia of the hip (DDH); we therefore investigated whether multiple births have a higher incidence of DDH, and if selective ultrasound scanning should be considered for these infants.We reviewed our records of all live births between 1 January 2004 and 31 December 2008 and included 25 246 single and 990 multiple births.Multiple births did not have a significantly higher incidence of DDH compared with single births (0.0030 vs 0.0023, p = 0.8939). Of the 990 multiple births, 267 had neonatal ultrasound scans and one case of DDH was diagnosed and treated successfully with a Pavlik harness. There were two late-presenting cases at eight and 14 months of age, neither of whom had risk factors for DDH and consequently had not had a neonatal scan. Whereas selective ultrasound scanning of multiple births would have led to earlier detection and treatment of the late-presenting cases, they did not have a significantly higher incidence of DDH compared with single births.We conclude that being a twin or triplet in itself is not a risk factor for DDH and that selective ultrasound scanning is not indicated for this population.