title: MR imaging findings of medial tibial crest friction.
abstract: OBJECTIVE
  Medial tibial condyle bone marrow edema (BME), associated with soft tissue edema (STe) surrounding the medial collateral ligament, was incidentally observed in MRI examinations of young and athletic individuals. The aim of the present study was to 1. Prospectively investigate the association between these findings and coexistence of localized pain, and 2. Explore the possible contribution of the tibial morphology to its pathogenesis.
  
  
  METHODS
  The medial tibial condyle crest was evaluated in 632 knee MRI examinations. The angle and depth were measured by two separate evaluators. The presence of STe and BME was recorded. A third evaluator blindly assessed the presence of pain at this site.
  
  
  RESULTS
  BME associated with STe was found in 24 patients (with no history of previous trauma, osteoarthritis, tumor or pes anserine bursitis). The mean crest angle was 151.3° (95%CI 147.4-155.3°) compared to 159.4° (95%CI 158.8-160°) in controls (Mann-Whitney test, P<0.0001). MRI findings were highly predictive of localized pain (sensitivity 92% specificity 99%, Fisher's exact test, P<0.0001).
  
  
  CONCLUSIONS
  Friction at the medial tibial condyle crest is a painful syndrome. MRI is a highly specific and sensitive imaging modality for its diagnosis.
authors.affiliation: Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece. Electronic address: miklontzas@gmail.com.
authors.forename: Michail E
authors.initials: ME
authors.lastname: Klontzas
authors.forename: Ioannis D
authors.initials: ID
authors.lastname: Akoumianakis
authors.forename: Ilias
authors.initials: I
authors.lastname: Vagios
authors.forename: Apostolos H
authors.initials: AH
authors.lastname: Karantanas
mesh_terms: D000328:Adult; D005260:Female; D017276:Friction; D006801:Humans; D007719:Knee Joint / Q000473:pathology* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013977:Tibia / Q000473:pathology* / Q000503:physiopathology*
keywords: Bone marrow edema; Friction syndrome; MR imaging/diagnosis; Medial knee pain; Medial tibial condyle