title: Long-term outcome following medial open reduction in developmental dysplasia of the hip: a retrospective cohort study.
abstract: BACKGROUND
  Avascular necrosis (AVN) is a serious complication of treatment for developmental dysplasia of the hip. There is ongoing controversy regarding AVN and its influence on hip development following medial open reduction (MOR).
  
  
  OBJECTIVE
  The aim of our study was to (1) determine the long-term prevalence of AVN following MOR, (2) evaluate hip development after MOR, and (3) identify predictors of AVN and radiographic outcome at skeletal maturity after MOR.
  
  
  METHODS
  A retrospective cohort analysis of 60 patients (70 hips) who underwent MOR with a mean follow-up of 10.83 years (5.23-16.74) was conducted. AVN was recorded according to Bucholz and Ogden classification and radiographic outcome based on Severin grading. AVN and hip morphology related to length of follow-up were evaluated. Chi-squared and t-tests were used to identify relationships between AVN and other variables. Logistic regression was used to assess predictors of AVN and Severin outcome.
  
  
  RESULTS
  The rate of clinically significant AVN (types 2-4) following MOR was 32.9 % with type 2 accounting for 82.6 % of these cases. While early acetabular development was satisfactory, long-term outcome was unsatisfactory in 26 % of cases with AVN (vs 8.7 % of cases without AVN). A higher rate of AVN was identified when hips were immobilized in ≥60° of abduction postoperatively. A higher rate of poor Severin outcome was identified in hips with AVN.
  
  
  CONCLUSIONS
  Our findings suggest that there is a high rate of AVN and unsatisfactory long-term outcome following MOR. AVN remains a significant concern following MOR surgery for developmental dysplasia of the hip that may not be apparent until long-term evaluation.
authors.affiliation: CURE Ethiopia Children's Hospital, Addis Ababa, Ethiopia. richard.gardner@cureinternational.org.
authors.forename: Richard O E
authors.initials: RO
authors.lastname: Gardner
authors.affiliation: Department of Rehabilitation Services, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
authors.forename: Catharine S
authors.initials: CS
authors.lastname: Bradley
authors.affiliation: Division of Orthopaedic Surgery, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
authors.forename: Om P
authors.initials: OP
authors.lastname: Sharma
authors.affiliation: Department of Orthopaedic Surgery, Xiamen Woman and Children's Hospital, Xiamen, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Surgery, Mt. Sinai Hospital, Toronto, Canada.
authors.forename: Michelle EyunJung
authors.initials: ME
authors.lastname: Shin
authors.affiliation: Division of Orthopaedic Surgery, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Kelley
authors.affiliation: Division of Orthopaedic Surgery, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
authors.forename: J H
authors.initials: JH
authors.lastname: Wedge
keywords: Avascular necrosis; Developmental dysplasia of the hip; Hip dislocation; Medial open reduction