title: Acutely injured knee: effect of MR imaging on diagnostic and therapeutic decisions.
abstract: OBJECTIVE
  To assess the effect of knee magnetic resonance (MR) imaging on the diagnosis and management of acute knee injury.
  
  
  METHODS
  Two orthopedic knee surgeons prospectively completed pre- and post-MR imaging questionnaires on 84 of 91 consecutive patients with acute knee injury. The pre- and post-MR imaging clinical diagnoses, certainty regarding these diagnoses, other diagnostic tests, and subjective impression of the usefulness of MR imaging were determined.
  
  
  RESULTS
  Seven hundred thirty-one of 840 pre- and post-MR imaging diagnoses agreed. Agreement was lowest for medial meniscal injuries (54 of 84). Significantly fewer meniscal injuries were suspected after MR imaging (P < .05). In 60 patients, the orthopedist changed at least one of the 10 potential diagnoses after MR imaging. Clinical diagnostic certainty increased by a mean of 14% for all diagnoses. The increase in diagnostic certainty was greatest for medial meniscal injuries (30%), followed by lateral meniscal injuries (21%). The proposed management changed in 41 patients, resulting in significantly fewer arthroscopic procedures (P < .01). The post-MR imaging management plans included 37% (27 of 73) fewer arthroscopic procedures.
  
  
  CONCLUSIONS
  MR imaging affects the diagnosis and management of acute knee injury by decreasing the number of arthroscopic procedures, improving clinician diagnostic certainty, and assisting in management decisions.
authors.affiliation: Department of Radiology, University of Virginia Health Sciences Center, Charlottesville 22908, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Maurer
authors.forename: P A
authors.initials: PA
authors.lastname: Kaplan
authors.forename: R G
authors.initials: RG
authors.lastname: Dussault
authors.forename: D R
authors.initials: DR
authors.lastname: Diduch
authors.forename: A
authors.initials: A
authors.lastname: Schuett
authors.forename: F C
authors.initials: FC
authors.lastname: McCue
authors.forename: P P
authors.initials: PP
authors.lastname: Hornsby
authors.forename: B J
authors.initials: BJ
authors.lastname: Hillman
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000628:therapy; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009985:Orthopedics; D011446:Prospective Studies; D011795:Surveys and Questionnaires