title: [Osteochondritis dissecans - an easy classification in MRI].
abstract: OBJECTIVE
  For the diagnosis of osteochondritis dissecans (OD) MRI is used besides X-ray. However, there is no consensus about the necessity of MRI or the interpretation of MRI. The aim of this prospective study was to find a diagnostic concept for OD which is simple and practicale for daily routine.
  
  
  METHODS
  In 90 patients with OD of the knee or ankle MRI (T1- and T2-w SE) was carried out before arthroscopy. According to the interface between the osteochondral fragment and the parent bone, MRI was classified in 2 stages ("stable" or "unstable") and compared with the arthroscopic findings.
  
  
  RESULTS
  With the 2-stage classification of MRI, a prediction of the stability of the osteochondral fragment was possible in 92 %. Out of the 90 patients 7 (8 %) differed regarding preoperative stability in MRI compared to stability in arthroscopy. Incorrect diagnosis in MRI was only found among the patients with unstable fragments.
  
  
  CONCLUSIONS
  The chosen 2-stage classification in MRI is well suitable for the planning of stage-related therapy.
authors.affiliation: Orthopädische Klinik und Poliklinik der Justus-Liebig-Universität Giessen, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Jürgensen
authors.forename: G
authors.initials: G
authors.lastname: Bachmam
authors.forename: I
authors.initials: I
authors.lastname: Schleicher
authors.forename: H
authors.initials: H
authors.lastname: Haas
mesh_terms: D000293:Adolescent; D000328:Adult; D000843:Ankle Joint / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010008:Osteochondritis Dissecans / Q000145:classification* / Q000175:diagnosis; D012680:Sensitivity and Specificity