title: Bone marrow edema and associated pain in early stage osteonecrosis of the femoral head: prospective study with serial MR images.
abstract: OBJECTIVE
  To determine whether the marrow edema around focal osteonecrosis on magnetic resonance (MR) images is associated with clinical symptoms.
  
  
  METHODS
  Thirty-three patients with 37 hips showing early stage osteonecrosis of the femoral head were followed up at 3-month intervals with clinical evaluation, conventional radiography, and serial MR imaging.
  
  
  RESULTS
  Seven (50%) of 14 symptomatic hips showed marrow edema around focal osteonecrosis on initial MR images, whereas only one (4%) of 23 asymptomatic hips showed edema (P < .01). Six (86%) of seven hips that were moderately to severely painful were associated with surrounding marrow edema. All eight hips showing osteonecrosis with marrow edema at the initial MR examination had joint effusion and exhibited intense radionuclide uptake in the proximal femur, which corresponded to the extent of edema on MR images. In all eight hips, the marrow edema resolved on follow-up MR images, and the pain subsided with the resolution of edema.
  
  
  CONCLUSIONS
  The results of this study suggest that the combination of marrow edema of the proximal femur and focal osteonecrosis of the femoral head are strongly associated with hip pain in early stage osteonecrosis, even prior to collapse. Pain improvement usually parallels the resolution of edema.
authors.affiliation: Department of Orthopedic Surgery, Gyeong-Sang National University School of Medicine, Chinju, South Korea. khkoo@nongae.gsnu.ac.kr
authors.forename: K H
authors.initials: KH
authors.lastname: Koo
authors.forename: I O
authors.initials: IO
authors.lastname: Ahn
authors.forename: R
authors.initials: R
authors.lastname: Kim
authors.forename: H R
authors.initials: HR
authors.lastname: Song
authors.forename: S T
authors.initials: ST
authors.lastname: Jeong
authors.forename: J B
authors.initials: JB
authors.lastname: Na
authors.forename: Y S
authors.initials: YS
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Cho
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000473:pathology*; D019299:Decompression, Surgical; D004487:Edema / Q000175:diagnosis*; D005260:Female; D005270:Femur Head / Q000473:pathology / Q000601:surgery; D005271:Femur Head Necrosis / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged