Of the 34 723 infants born between 1 June 1992 and 31 May 2002, the hips of 2578 with clinical instability or at-risk factors for developmental dysplasia of the hip were imaged by ultrasound.

Instability of the hip was present in 77 patients, of whom only 24 (31.2%) had an associated risk factor. From the ‘at-risk’ groups, the overall risk of type-III dysplasia, instability and irreducibility was 1:15 when family history, 1:27 when breech delivery and 1:33 when foot deformity were considered as risk factors. Of those hips which were ultrasonographically stable, 88 had type-III dysplasia.

A national programme of selective ultrasound screening of at-risk factors for the diagnosis of hip dislocation or instability alone cannot be recommended because of its low predictive value (1:88). However, the incidence of type-III dysplasia and hip dislocation or dislocatability in the groups with clinical instability, family history, breech position and possibly postural foot deformity as risk factors could justify a programme of selective ultrasound imaging.

This study was undertaken between May 1992 and April 2002 in a hospital where there was a targeted screening programme for Developmental Dysplasia of the Hip. All data was collected prospectively. 2,578 infants with clinically unstable or at risk hips underwent bilateral hip ultrasound examination. This was performed by the senior author. At risk hips were considered to be those where there was a history of breech presentation, foot deformity, oligohydramnios on prenatal maternal ultrasound scans or a strong family history of Developmental Dysplasia of the Hip. There were significant changes in the reasons for referral for targeted screening over the ten year period. In the first year of the study 1.5% of referrals were because of oligohydramnios. In the last year of the survey 16.5% of referrals were because of oligohydramnios. The number of referrals for screening because of oligohydramnios increased sixty fold between the first year and last year of the study period. The overall number of infants referred for targeted screening more than doubled between the first and the last year of the study period. Of the infants that were found to have unstable or dislocated hips, no infants had oligohydramnios as a risk factor. The number of referrals for targeted ultrasound screening is increasing. In a targeted screening programme for Developmental Dysplasia of the Hip we suggest that oligohydramnios should not be used as a possible risk factor.