title: Fibrous scar in the infrapatellar fat pad after arthroscopy: MR imaging.
abstract: OBJECTIVE
  We describe the MR appearance of fibrous scars in the infrapatellar fat pad after arthroscopy.
  
  
  METHODS
  The subjects were 96 patients who underwent arthroscope-assisted anterior cruciate ligament (ACL) reconstruction and were examined by oblique sagittal MR imaging at different follow-up intervals. Two observers evaluated the characteristics of the fibrous scars in the infrapatellar fat pad.
  
  
  RESULTS
  All fibrous scars with low signal intensity were accentuated at the portal and coursed horizontally through the infrapatellar fat pad. The fibrous scar within the fat pad occurred and peaked within 6 months after arthroscopy. It then subsided gradually and had disappeared by one year later in nearly half of the patients.
  
  
  CONCLUSIONS
  Identifying MR imaging characteristics of fibrous scars in the fat pad after arthroscopy may be clinically helpful to differentiate these scars from other abnormalities that involve the infrapatellar fat pad.
authors.affiliation: Department of Radiology, Institute of Clinical Medicine, University of Tsukuba, Japan.
authors.forename: G
authors.initials: G
authors.lastname: Tang
authors.forename: M
authors.initials: M
authors.lastname: Niitsu
authors.forename: K
authors.initials: K
authors.lastname: Ikeda
authors.forename: H
authors.initials: H
authors.lastname: Endo
authors.forename: Y
authors.initials: Y
authors.lastname: Itai
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001182:Arthroscopy / Q000009:adverse effects / Q000379:methods; D016009:Chi-Square Distribution; D002921:Cicatrix / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D005355:Fibrosis; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010329:Patella / Q000473:pathology*; D012075:Remission, Spontaneous; D012189:Retrospective Studies