title: Acetabular Remodeling and Role of Osteotomy After Closed Reduction of Developmental Dysplasia of the Hip.
abstract: BACKGROUND
  The purposes of this study were to evaluate acetabular remodeling after closed reduction of developmental dysplasia of the hip (DDH) and to delineate the role of osteotomy.
  
  
  METHODS
  Eighty-four hips with DDH treated with closed reduction and followed until the patient was 8 years of age or older were included in this study. The mean age at closed reduction was 14.0 months (range, 3 to 30 months) and that at the latest follow-up visit was 12.7 years (range, 8.0 to 24.7 years). Osteotomy was performed in 26 hips (31%) during the follow-up period, at an average age of 2.8 years (range, 2.0 to 5.8 years). The acetabular index (AI) and center-edge angle (CEA) were measured, and osteonecrosis was graded. The treatment outcome was evaluated as satisfactory (Severin grade I or II) or unsatisfactory (III or IV). We retrospectively analyzed the associations among radiographic parameters, performance of osteotomy, grade of osteonecrosis, and final outcome.
  
  
  RESULTS
  A satisfactory outcome was observed in 67 (80%) of the 84 hips. An osteotomy was not performed in 30 of 34 hips with an AI of <32° and a CEA of >14° at the age of 3 years, and 28 (93%) of these 30 hips showed a satisfactory outcome. Of the 33 hips with an AI of ≥32° and a CEA of ≤14° at the age of 3 years, the 20 that had undergone an osteotomy showed a higher proportion of satisfactory outcomes than the 13 hips that had not (p = 0.01). Three of the 4 hips that showed an unsatisfactory outcome following an osteotomy had an AI of ≥34° at 1 year post-osteotomy. Grade-II, III, or IV osteonecrosis, according to the Bucholz-Ogden classification, developed in 10 of the 84 hips, and these 10 hips had a higher proportion of unsatisfactory outcomes than did those that developed no or grade-I osteonecrosis (p = 0.004).
  
  
  CONCLUSIONS
  Hips with DDH showing poor acetabular remodeling after closed reduction may benefit from osteotomy. The AI and CEA at the age of 3 years can serve as one of the guidelines for osteotomy. Continued surveillance for acetabular remodeling is required even after osteotomy.
  
  
  METHODS
  Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea drshinch@gmail.com.
authors.forename: Chang Ho
authors.initials: CH
authors.lastname: Shin
authors.affiliation: Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea yoowj@snu.ac.kr.
authors.forename: Won Joon
authors.initials: WJ
authors.lastname: Yoo
authors.affiliation: Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Republic of Korea pmsmed@gmail.com.
authors.forename: Moon Seok
authors.initials: MS
authors.lastname: Park
authors.affiliation: Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea archpegasi@gmail.com.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea inhoc@snu.ac.kr.
authors.forename: In Ho
authors.initials: IH
authors.lastname: Choi
authors.affiliation: Division of Pediatric Orthopaedics, Seoul National University Children's Hospital, Seoul, Republic of Korea tjcho@snu.ac.kr.
authors.forename: Tae-Joon
authors.initials: TJ
authors.lastname: Cho
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D002675:Child, Preschool; D005260:Female; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006801:Humans; D007223:Infant; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome