title: [The value of MR tomography in traumatic patella dislocations].
abstract: OBJECTIVE
  To describe the MR imaging findings in patients with lateral patellar dislocation.
  
  
  METHODS
  The MRIs of 31 patients with patellar dislocation were evaluated retrospectively. Arthroscopic surgery was performed in 23 cases.
  
  
  RESULTS
  Hemarthrosis was found in 30/31, contusions of the lateral femoral condyle in 30/31 and of the medial patellar facet in 26/31 cases. Injury of the medial patellar retinaculum was seen in 28/31 cases. Osteochondral fractures were found in 18 patients; compared to arthroscopy there were one false-positive and 5 false-negative findings concerning loose cartilage bodies. In 7 cases, patellar dislocation was not suspected before MR imaging.
  
  
  CONCLUSIONS
  Hemarthrosis, lateral femoral and medial patellar contusion, and retinacular disruption are typical findings after lateral patellar dislocation. A careful search for free osteochondral fragments is mandatory as it influences the indication and performance of arthroscopic surgery.
authors.affiliation: Klinik und Poliklinik für Radiologie, Johannes Gutenberg-Universität Mainz.
authors.forename: K F
authors.initials: KF
authors.lastname: Kreitner
authors.forename: P
authors.initials: P
authors.lastname: Grebe
authors.forename: M
authors.initials: M
authors.lastname: Runkel
authors.forename: S
authors.initials: S
authors.lastname: Schadmand-Fischer
authors.forename: A
authors.initials: A
authors.lastname: Meurer
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D002648:Child; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000000981:diagnostic imaging / Q000293:injuries* / Q000473:pathology*; D011859:Radiography; D012189:Retrospective Studies; D012421:Rupture
vernacular_title: Stellenwert der MR-Tomographie bei traumatischen Patellaluxationen.