title: Do we need to follow up an early normal ultrasound with a later plain radiograph in children with a family history of developmental dysplasia of the hip?
abstract: BACKGROUND
  We routinely perform a pelvic radiograph between 6 and 12 months of age for children with a family history of developmental dysplasia of hip (DDH). We conducted this study to determine whether children with a family history of DDH and a normal hip ultrasound after birth require any further radiological follow-up.
  
  
  METHODS
  We identified all children referred to our hip-screening clinic in a 3-year period between August 2008 and August 2011 with a family history of DDH and a normal hip ultrasound after birth. A total of 119 patients with a normal hip ultrasound after birth had a pelvic radiograph at a median age of 6.6 months.
  
  
  RESULTS
  Six patients had residual dysplasia (acetabular index >30°) on the initial radiograph; five of these had resolved spontaneously by age 12 months, and the remaining patient had a normal radiograph at 21 months of age and was discharged.
  
  
  CONCLUSIONS
  We have found no cases of residual hip dysplasia requiring treatment in children with a family history of DDH and a normal hip ultrasound after birth. We have therefore changed our practice accordingly and no longer routinely followed up such cases.
  
  
  METHODS
  Diagnostic study, Level II.
authors.affiliation: Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3NE, UK. stafazal@hotmail.com.
authors.forename: Suhayl
authors.identifier: http://orcid.org/0000-0003-2089-2408
authors.initials: S
authors.lastname: Tafazal
authors.affiliation: Sheffield Children's Hospital, Western Bank, Sheffield, S10 2TH, UK.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Flowers
mesh_terms: D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011859:Radiography; D012189:Retrospective Studies; D014463:Ultrasonography
keywords: Developmental dysplasia hip; Family history; Radiograph; Ultrasound