title: Patients with suspected meniscal tears: prevalence of abnormalities seen on MRI of 100 symptomatic and 100 contralateral asymptomatic knees.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the prevalence of MR abnormalities of the knee on the symptomatic and contralateral asymptomatic sides in patients with suspected meniscal tears. SUBJECTS AND METHODS. One hundred patients (mean age, 42.7 years; range, 18-73 years) referred for suspected meniscal tears were prospectively examined with MRI of both knees when the contralateral knee was asymptomatic. The prevalence of various types of meniscal tears and other MR abnormalities was determined.
  
  
  RESULTS
  Meniscal tears were found in 57 symptomatic knees and in 36 contralateral asymptomatic knees. In those 57 patients with a meniscal tear on the symptomatic side, the prevalence of asymptomatic tears in the contralateral side was 63% (36/57). Horizontal or oblique meniscal tears were found medially in 32 and laterally in 11 symptomatic knees, and medially in 29 and laterally in eight asymptomatic knees. Radial, vertical, complex, or displaced tears were found medially in 18 and laterally in five symptomatic knees, and medially in five and laterally in none of the asymptomatic knees. Collateral ligament abnormalities were found in 53 symptomatic knees and in six asymptomatic knees. Pericapsular soft-tissue abnormalities were found in 64 symptomatic and in 12 asymptomatic knees. Edema-like bone marrow abnormalities were found in 36 symptomatic and in three asymptomatic knees.
  
  
  CONCLUSIONS
  Horizontal or oblique meniscal tears are frequently encountered in both asymptomatic and symptomatic knees and may not always be related to symptoms. However, radial, vertical, complex, or displaced meniscal tears and abnormalities of the collateral ligaments, pericapsular soft tissues, and bone marrow are found almost exclusively on the symptomatic side and appear to be clinically more meaningful.
authors.affiliation: Department of Radiology, Orthopedic University Hospital Balgrist, Forchstr. 340, CH-8008 Zurich, Switzerland. marco.zanetti@balgrist.ch
authors.forename: Marco
authors.initials: M
authors.lastname: Zanetti
authors.forename: Christian W A
authors.initials: CW
authors.lastname: Pfirrmann
authors.forename: Marius R
authors.initials: MR
authors.lastname: Schmid
authors.forename: José
authors.initials: J
authors.lastname: Romero
authors.forename: Burkhardt
authors.initials: B
authors.lastname: Seifert
authors.forename: Juerg
authors.initials: J
authors.lastname: Hodler
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007717:Knee / Q000002:abnormalities* / Q000473:pathology*; D007718:Knee Injuries / Q000453:epidemiology* / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D017888:Medial Collateral Ligament, Knee / Q000002:abnormalities / Q000293:injuries / Q000473:pathology; D008592:Menisci, Tibial / Q000002:abnormalities* / Q000473:pathology; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D000070600:Tibial Meniscus Injuries; D015599:Trauma Severity Indices