Q&A

Ultrasonography helpful in diagnosing developmental hip dysplasia

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  • BACKGROUND: Developmental dysplasia of the hips is a condition that can impair normal growth and development of the hip, leading to abnormalities of gait and early degenerative changes of the joint. The Ortolani-Barlow test has been the mainstay for screening for hip instability, but the use of ultrasonography has increased over the last 20 years. Splinting and surgery have potential risks and costs, and ultrasound may assist in focusing such treatments on those who truly need either intervention.
  • POPULATION STUDIED: The researchers studied 629 infants aged <43 days, recruited from 33 centers in the United Kingdom and Ireland, that had been diagnosed with neonatal hip instability. They excluded infants who had already undergone ultrasonography of their hips, those where immediate splinting of the hip was a certainty, and those with a hip click without signs of instability. Infants with clinically normal hips who had recognized risk factors for subsequent dislocation were also excluded.
  • STUDY DESIGN AND VALIDITY: This randomized controlled trial allocated (in a concealed manner) 314 infants to diagnosis and management with ultrasonography and 315 to clinical examination alone. Infants randomized to ultrasonography received static and dynamic ultrasounds of the hip at age 2 weeks. The hip was splinted if it appeared significantly unstable or displaced initially, or if minor abnormalities persisted up to age 8 weeks. In the no-ultrasound group, the infant underwent splinting if clinical suspicion was high enough initially or if a specialist found the hip to be unstable up to age 8 weeks.
  • OUTCOMES MEASURED: The primary outcome was the appearance of abnormalities on hip radiographs at age 2 years. Secondary outcomes measured were the amount of required hip treatment (specifically surgery and splinting), as well as level of mobility, resource use, and cost.
  • RESULTS: Twenty-one children had abnormal or borderline radiographs by age 2 years in both groups. The 10 children with abnormal radiographs (4 of whom were in the ultrasound group) all started treatment before age 8 weeks. Overall, fewer children from the ultrasound group received treatment of any kind (relative risk=0.79; 95% confidence interval, 0.67–0.95), and this difference was almost entirely due to less splinting in the ultrasound group (37% vs. 48%).


 

PRACTICE RECOMMENDATIONS

Ultrasonography for diagnosis and management of possible hip instability may lead to less splinting and surgery in the first 2 years of life, with no significant difference in radiographic abnormalities. Cost-effectiveness, long-term hip mobility, and consistency of ultrasound interpretation is not proven.

The Journal of Family Practice ©2003 Dowden Health Media

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