title: Is there an association between epiphyseal scar and osteonecrosis of the femoral head?
abstract: OBJECTIVE
  To investigate statistical association between epiphyseal scar and osteonecrosis of the femoral head (ONFH) with magnetic resonance (MR) imaging.
  
  
  METHODS
  We retrospectively reviewed 71 consecutive patients who underwent MR imaging of bilateral hips that showed nontraumatic ONFH. There were 110 hips with ONFH and 31 normal hips; one hip received bipolar arthroplasty before the MR studies. All cases of ONFH had typical MR findings. The epiphyseal scars in the femoral head were classified as type I (a sealed-off scar) or type II (a perforated scar). Bone marrow edema, if present, in the proximal femur was identified on coronal T2-weighted or STIR MR images.
  
  
  RESULTS
  The type of femoral epiphyseal scar was clearly delineated in 97 hips. In cases with ONFH, a type I scar occurred in 46 hips (64%), and a type II scar in 26 hips (36%). In cases of ONFH with bone marrow edema, 69% of hips (24/35) had a type I scar and 31% of hips (11/35) had a type II scar. There was no statistical association between the type of epiphyseal scar and ONFH, regardless of staging (P=0.29), or the type of scar and bone marrow edema (P=0.42).
  
  
  CONCLUSIONS
  There is not a significant statistical association between a sealed-off scar and ONFH.
authors.affiliation: Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan, ROC.
authors.forename: Guo-Shu
authors.initials: GS
authors.lastname: Huang
authors.forename: Herng-Sheng
authors.initials: HS
authors.lastname: Lee
authors.forename: Min-Szu
authors.initials: MS
authors.lastname: Yao
authors.forename: Wing P
authors.initials: WP
authors.lastname: Chan
mesh_terms: D000328:Adult; D005260:Female; D005271:Femur Head Necrosis / Q000473:pathology*; D006132:Growth Plate / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index