title: The Use of MRI in Evaluating Knee Pain in Patients Aged 40 Years and Older.
abstract: BACKGROUND
  The use of MRI is increasing when evaluating patients with knee pain because it is highly sensitive for detecting intra-articular pathology. However, such changes can be associated with degenerative joint disease, which may be demonstrated with weight-bearing radiographs. The purpose of this study was to determine how often MRI was obtained before orthopaedic referral in patients aged ≥40 years with knee pain, how often weight-bearing radiographs were obtained before MRI, and whether such imaging influenced treatment recommendations.
  
  
  METHODS
  In a study of 599 new patients, participating physicians documented the presence of a prereferral MRI and/or plain radiographic studies, the results of weight-bearing radiographs, treatment recommendations, and the impact of any prereferral imaging.
  
  
  RESULTS
  Prereferral use of MRI occurred in 130 patients (22%). Of these patients, plain radiographic studies were obtained for 58% before MRI and 13% had weight-bearing radiographs. Ultimately, 17% had weight-bearing radiographs that demonstrated >50% loss of joint space. Forty-eight percent of prereferral MRIs did not contribute to treatment recommendations. In patients with >50% loss of joint space, MRI was considered unnecessary in 95% of the cases.
  
  
  CONCLUSIONS
  Many prereferral MRIs do not contribute to clinical decision making. Weight-bearing radiographs can help identify those patients in whom MRI is unlikely to be helpful.
  
  
  METHODS
  Level III.
authors.affiliation: From the Department of Orthopedics, Washington University, St. Louis, MO (Dr. Adelani, Dr. Brophy, Dr. Halstead, Dr. Smith, and Dr. Wright) and St. Louis Center for Cartilage Restoration and Repair, St. Louis (Dr. Mall).
authors.forename: Muyibat A
authors.initials: MA
authors.lastname: Adelani
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Mall
authors.forename: Robert H
authors.initials: RH
authors.lastname: Brophy
authors.forename: Mark E
authors.initials: ME
authors.lastname: Halstead
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Smith
authors.forename: Rick W
authors.initials: RW
authors.lastname: Wright
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D011859:Radiography / Q000379:methods; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D016474:Weight-Bearing