title: The Frequency of AVN Following Reconstructive Hip Surgery in Children With Cerebral Palsy: A Systematic Review.
abstract: BACKGROUND
  Children with cerebral palsy (CP) undergoing reconstructive hip surgery are at risk for developing avascular necrosis (AVN). The purpose of this systematic review was to investigate the reported frequency of AVN, the amount and quality of literature available, and possibly identity risk factors for developing AVN following reconstructive surgery for hip displacement in children with CP.
  
  
  METHODS
  We performed a review of the literature using EMBASE and MEDLINE databases. Studies investigating the outcome of reconstructive hip surgery in patients with CP that identified the presence or absence of AVN were included. Study quality was assessed using the Methodological Index for Non-Randomized Studies and the Oxford Centre for Evidence-Based Medicine scale.
  
  
  RESULTS
  Three hundred and ninety-nine articles were identified using our search strategy. Twenty-nine studies were included for data extraction after full-text review. The frequency of AVN ranged from 0% to 46% with an overall rate across studies of 7.5%. Presence of AVN was the primary outcome in 2 studies. The frequency of AVN in these studies was significantly higher than other studies at 37% and 46%. No statistically significant associations were found between age at surgery, severity of hip subluxation, length of follow-up, or type of surgery (combined varus derotation osteotomy and pelvic osteotomy vs. varus derotation osteotomy alone), and the rate of AVN. The majority of studies did not comment on methods used for determining diagnosis or severity of AVN and clinical significance was not well documented.
  
  
  CONCLUSIONS
  Children with CP undergoing reconstructive hip surgery are at risk of developing AVN. Frequency and severity of this complication is poorly documented in the literature. On the basis of current evidence no significant risk factors were identified; however, it is not possible to draw firm conclusions about them. Incidence of AVN was higher in studies in which AVN was a primary outcome suggesting that the true frequency of AVN may be higher than is currently understood.
authors: *Department of Orthopedic Surgery, BC Children's Hospital†Faculty of Medicine‡Department of Orthopedics, University of British Columbia, Vancouver, BC, Canada.
authors: Kim
authors: K
authors: Hesketh
authors: Lise
authors: L
authors: Leveille
authors: Kishore
authors: K
authors: Mulpuri
mesh_terms: D002547:Cerebral Palsy / Q000150:complications*; D002648:Child; D005271:Femur Head Necrosis / Q000209:etiology*; D006617:Hip Dislocation / Q000601:surgery*; D006801:Humans; D011183:Postoperative Complications; D012307:Risk Factors