title: Failed Pavlik harness treatment for DDH as a risk factor for avascular necrosis.
abstract: BACKGROUND
  Avascular necrosis (AVN) of the femoral head is an irreversible complication seen in the treatment of developmental dysplasia of hip (DDH) with the Pavlik harness. Its incidence is reported to be low after successful reduction of the hip but high if the hip is not concentrically relocated. We aim to investigate its incidence after failed Pavlik harness treatment.
  
  
  METHODS
  We prospectively followed up a group of children who failed Pavlik harness treatment for DDH treated at our institution by the senior author between 1988 and 2001 and compared their rates of AVN with a group of children who presented late and hence were treated surgically. AVN was graded as described by Kalamchi and MacEwen and only grade 2 to 4 AVN was considered significant and included in the analysis.
  
  
  RESULTS
  Thirty-seven hips were included in the failed Pavlik group (group 1) and 86 hips in the no Pavlik group (group 2). Ten hips in group 1 developed AVN (27%), whereas only 7 hips in group 2 (8%) developed AVN; the odds of developing AVN after failed Pavlik treatment was 4.7 (95% confidence interval, 1.3-14.1) (P=0.009) with a relative risk of 3.32 (range, 1.37 to 8.05).
  
  
  CONCLUSIONS
  There was no statistically significant association observed with duration of splintage and severity of AVN (Spearman's correlation, -0.46; P=0.18). However, there was a positive correlation noted with age at presentation and severity of AVN. Therefore, we advise close monitoring of hips in the Pavlik harness and discontinue its use if the hips are not reduced within 3 weeks.
  
  
  METHODS
  Level III.
authors: *University Hospital Southampton Foundation Trust; Southampton General Hospital †NIHR Research Design Service South Central ‡University of Southampton and Child Health, University Hospital Southampton Foundation Trust, Southampton General Hospital, Southampton, UK.
authors: Madhu
authors: M
authors: Tiruveedhula
authors: Isabel C
authors: IC
authors: Reading
authors: Nicholas M P
authors: NM
authors: Clarke
mesh_terms: D001915:Braces / Q000009:adverse effects; D002675:Child, Preschool; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging*; D005271:Femur Head Necrosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D005500:Follow-Up Studies; D006618:Hip Dislocation, Congenital / Q000150:complications / Q000453:epidemiology / Q000628:therapy; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000379:methods; D056888:Patient Positioning / Q000009:adverse effects* / Q000379:methods; D011446:Prospective Studies; D012307:Risk Factors; D017211:Treatment Failure; D014463:Ultrasonography; D006113:United Kingdom / Q000453:epidemiology