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.
Conclusion: 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.