title: Accuracy of MRI in the diagnosis of meniscal tears in older patients.
abstract: OBJECTIVE
  The objective of our study was to determine the accuracy of MRI in diagnosing meniscal tears in older patients and the frequency with which abnormal MRI findings correlate with degeneration, fraying, and tears at arthroscopy.
  
  
  METHODS
  Ninety-two patients 50 years old or older who had undergone knee MRI followed by knee arthroscopy within 6 months were selected. Menisci were graded on a 5-point scale: 1, definitely no tear; 2, probably no tear; 3, indeterminate or equivocal; 4, probably a tear; and 5, definitely a tear. Meniscal signal changes, meniscal surface morphology, and extrameniscal abnormalities were noted. Operative notes were reviewed, and the sensitivity and specificity of MRI results were calculated.
  
  
  RESULTS
  For medial tears, MRI had a sensitivity and specificity of 0.91 and 0.94, respectively, when grade 5 was considered a tear, 0.96 and 0.76 when grades 4 and 5 were considered a tear, and 0.99 and 0.47 when grades 3-5 were considered a tear. For lateral tears, MRI had a sensitivity and specificity of 0.73 and 0.91 when grade 5 was considered a tear, 0.88 and 0.80 when grades 4 and 5 were considered a tear, and 1.0 and 0.61 when grades 3-5 were considered a tear. The positive predictive values (PPVs) of MRI for the medial meniscus were 99%, grade 5; 57%, grade 4; 29%, grade 3; 25%, grade 2; and 0%, grade 1. For the lateral meniscus, the PPVs of MRI were 76%, grade 5; 36%, grade 4; 19%, grade 3; and 0%, grades 1 and 2.
  
  
  CONCLUSIONS
  The accuracy of MRI for diagnosing meniscal tears in older patients is high and similar to that in younger patients when only definitive findings are considered a tear. The specificity decreases if equivocal or probable findings are considered a tear.
authors.affiliation: Imaging Institute, Cleveland Clinic, Cleveland, OH 44120, USA. subhasn@ccf.org
authors.forename: Naveen
authors.initials: N
authors.lastname: Subhas
authors.forename: Flavia A
authors.initials: FA
authors.lastname: Sakamoto
authors.forename: Michael W
authors.initials: MW
authors.lastname: Mariscalco
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Polster
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Obuchowski
authors.forename: Morgan H
authors.initials: MH
authors.lastname: Jones
mesh_terms: D000368:Aged; D001182:Arthroscopy; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D000070600:Tibial Meniscus Injuries