title: Post-closed reduction perfusion magnetic resonance imaging as a predictor of avascular necrosis in developmental hip dysplasia: a preliminary report.
abstract: BACKGROUND
  Avascular necrosis (AVN) of the femoral head remains a major complication in the treatment of developmental dysplasia of the hip (DDH) in infants. We performed a retrospective analysis to look at the predictive ability of postclosed reduction contrast-enhanced magnetic resonance imaging (MRI) for AVN after closed reduction in DDH.
  
  
  METHODS
  Twenty-eight hips in 27 infants (aged 1-11 months) with idiopathic hip dislocations who had failed brace treatment underwent closed reduction +/- adductor tenotomy and spica cast application under general anesthesia. Magnetic resonance imaging of the hips after intravenous gadolinium contrast injection for evaluation of epiphyseal perfusion was obtained immediately after cast application. Patients were followed with serial radiographs for a minimum of 1 year after closed reduction. Presence of AVN was determined by the presence of any one of the 5 Salter criteria by 2 readers. Magnetic resonance imaging was graded as normal, asymmetric enhancement, focal decreased enhancement, or global decreased enhancement by 2 radiologists.
  
  
  RESULTS
  Six (21%) of 28 hips showed evidence of clinically significant AVN on follow-up radiographs. Fifty percent of the hips with AVN, but only 2 of 22 hips without AVN, showed a global decreased MRI enhancement (P < 0.05, Fisher exact test). Multivariate logistic regression indicated that a global decreased enhancement was associated with a significantly higher risk of developing AVN (P < 0.01), independently of age at reduction (P = 0.02) and abduction angle.
  
  
  CONCLUSIONS
  In addition to accurate anatomical assessment of a closed reduction in DDH, gadolinium-enhanced MRI provides information about femoral head perfusion that may be predictive for future AVN. At present, it is premature to use the perfusion information for routine clinical use. However, it opens the door to studies looking at repositioning or alternative reduction methods that may reduce the risk of AVN in this higher risk group.
authors.affiliation: Department of Orthopaedic Surgery, Children's Hospital-Boston, Boston, MA, USA.
authors.forename: Carl
authors.initials: C
authors.lastname: Tiderius
authors.forename: Diego
authors.initials: D
authors.lastname: Jaramillo
authors.forename: Susan
authors.initials: S
authors.lastname: Connolly
authors.forename: Michael
authors.initials: M
authors.lastname: Griffey
authors.forename: Diana P
authors.initials: DP
authors.lastname: Rodriguez
authors.forename: James R
authors.initials: JR
authors.lastname: Kasser
authors.forename: Michael B
authors.initials: MB
authors.lastname: Millis
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.forename: Young-Jo
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D000367:Age Factors; D005260:Female; D005271:Femur Head Necrosis / Q000175:diagnosis* / Q000209:etiology; D005500:Follow-Up Studies; D005682:Gadolinium; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000175:diagnosis* / Q000209:etiology; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D005682:Gadolinium