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.