Screening for developmental dysplasia of the hip in Hong Kong.

Purpose: To review records of children referred to our hospital for developmental dysplasia of the hip (DDH) and evaluate the effectiveness of hip screening in Hong Kong.

Methods: Records of children suspected of DDH and referred to our hospital between 1 January 2005 and 31 March 2010 were reviewed. The diagnosis was based on static and dynamic ultrasonography of the hips and/or radiographic features of hip subluxation, dislocation, and pelvic dysplasia. The age of the children at presentation was recorded. Late diagnoses were those presenting after the age of 6 months. Late presentations were those presenting after the walking age.

Results: Of 213 referred children, 33 were diagnosed to have DDH. Their mean age at presentation was 90.8 (range, 9-559) days. The female-to-male ratio was 2.9:1, and the mean follow-up duration was 25.1 (range, 4.2-50.3) months. 30 of the DDH infants were diagnosed before the age of 6 months, one at 8 months, and 2 were late presenters. Hence, the failure rate of the hip screening was 0.09 per 1000 live births. The remaining 180 were confirmed to be normal and followed up until the walking age. The point prevalence of DDH on Hong Kong Island was 0.87/1000 live births.

Conclusion: In light of the low point prevalence of DDH in Hong Kong born children, the protocol of universal clinical assessment and selective ultrasonographic screening of suspected cases is justified.