Auditing hip ultrasound screening of infants at increased risk of developmental dysplasia of the hip.

BACKGROUND: Clinical examination, while useful, has been shown to be insufficient as the sole screening method in infants. Ultrasound examination at 8 weeks in high risk infants is an integral part of the screening process in some units. AIMS: To show the efficiency of hip sonography in detection of developmental dysplasia of the hips in those without clinically dislocated hips. METHODS: All infants born at the National Maternity Hospital between January 1994 and December 2001 were included. All those with clinically dislocated hips were treated by a Pavlik harness and referred for follow up to a paediatric orthopaedic surgeon. An 8 week hip ultrasound scan was performed for those infants with stable hips on examination but who met the following criteria: (1) a first degree relative with congenital dislocation of hips; (2) breech presentation at birth; and (3) a persistent "click" at birth in an otherwise stable hip. RESULTS: During the period of study a total of 52 893 infants were born in the National Maternity Hospital. Based on the criteria above, 5485 hip ultrasound scans were performed. Of those scanned, 18 (0.33%) were found to have dislocated hips and 153 (2.78%) to have dysplasic hips. The 18 infants with dislocation were treated with Pavlik harness; the remaining 153 were followed up by serial ultrasound examinations but did not require active intervention. CONCLUSIONS: Among the population of infants at increased risk of developmental dysplasia of the hip, the hip screening programme identified 18 cases among 5485 infants; a rate of 3.2 per 1000. Hip sonography is therefore worthwhile.