Ultrasound in the selective screening of developmental dysplasia of the hip.

INTRODUCTION: Developmental dysplasia of the hip (DDH) can result in chronic pain, gait abnormalities and degenerative arthritis. Infants with a family history, Breech delivery or unstable/"clicking" of the hip on examination are at higher risk. The goal is to detect cases early enough for normal hip development and function by the end of adolescence, but clinical examination alone is ineffective.

MATERIALS AND METHODS: All infants born at the West Middlesex University Hospital, Isle-worth, U.K., between 3/3/2005 and 21/10/2006 underwent prospective clinical screening to reveal risk factors of unstable hip on examination, family history of DDH and Breech delivery. Infants with risk factors underwent static and dynamic ultrasound of the hips (Harke's method with Terjesen measurements), performed by a consultant radiologist or sonographer. The infant was then examined by an Orthopaedic Surgeon who was blinded to the ultrasound findings until after creating a management plan.

RESULTS: 5772 infants were born during the study period. 200 (3.5%) at-risk infants were identified, resulting in 400 hip ultrasounds. Following review of ultrasound findings, the majority of cases (163/200, 81.5%) lead to no change in management. Change in timing or type of clinical follow up occurred in 31 cases with normal ultrasounds and 20 cases with abnormal (immature hip) ultrasounds. Dysplasia was demonstrated in 6 infants (3%) on ultrasound, who were treated with Parvlik Harness. Of these, only 5 were detected on examination. Therefore, the ultrasound findings lead to 1 intervention with Parvlik Harness which would have otherwise gone undiagnosed from clinical examination.

CONCLUSION: Whereas type and timing of follow up was adjusted in 18.5% of the at-risk infants, targeted screening of at-risk with ultrasound lead to only one intervention. This encourages discussion on the resource implication and viability of ultrasound screening, as only one from two hundred lead to an intervention.