title: Fat-suppressed T2-weighted MRI appearance of subchondral insufficiency fracture of the femoral head.
abstract: OBJECTIVE
  Our aims were to investigate the imaging appearance of subchondral insufficiency fracture (SIF) of the femoral head based on fat-suppressed T2-weighted MRI, and evaluate its correlation with the clinical outcomes following conservative treatment.
  
  
  METHODS
  We retrospectively evaluated 40 hips in 37 patients with SIF of the femoral head (12 males and 25 females; mean age 55.8 years, range 22-78 years). MRI examinations were performed within 3 months after the onset of hip pain. Using fat-suppressed T2-weighted imaging, we evaluated the hips for the intensity of the subchondral bone (corresponding to the area superior to the low intensity band on T1-weighted images) as well as bone marrow edema, joint effusion, and presence of the band lesion. We then correlated the intensity of the subchondral bone with clinical outcomes.
  
  
  RESULTS
  The hips were classified into three types based on subchondral intensity on fat-suppressed T2-weighted images: type 1 (21 hips) showed high intensity, type 2 (eight hips) showed heterogeneous intensity, and type 3 (11 hips) showed low intensity. The mean period between pain onset and MRI examination was significantly longer for type 2 hips than for type 1. Healing rates were 86 % for type 1, 75 % for type 2, and 18 % for type 3.
  
  
  CONCLUSIONS
  SIF cases were classified into three types based on subchondral intensity on fat-suppressed T2-weighted imaging performed within 3 months after pain onset. Type 3 SIF tended to be intractable to conservative treatment compared to type 1 and type 2.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sonoda
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan. yamataku@ortho.med.kyushu-u.ac.jp.
authors.forename: Takuaki
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Goro
authors.initials: G
authors.lastname: Motomura
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Karasuyama
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kubo
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology; D015775:Fractures, Stress / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D016896:Treatment Outcome; D055815:Young Adult
keywords: Fat-suppressed T2-weighted imaging; Femoral head; Magnetic resonance imaging; Subchondral insufficiency fracture