Knee sonography as a diagnostic test for medial meniscal tears in young patients.

Purpose: To prospectively evaluate whether age of patient affects diagnostic accuracy of sonography and magnetic resonance imaging (MRI) in the diagnosis of medial meniscal tears.

Methods: We prospectively evaluated 74 consecutive patients (54 males and 20 females), in two different groups [group A (37 patients ≤ 30 years; mean age: 23.5 ± 5 years) and group B (37 patients > 30 years; mean age: 43.5 ± 9.35 years)] with clinical suspicion of medial meniscal tear. After inclusion, patients underwent ultrasonography and then MRI for signs of tearing. The ultrasonographic and MRI findings were compared with arthroscopic findings, which served as a gold standard for accurate detection of meniscal tearing.

Results: The sensitivity, specificity, positive and negative predictive values and accuracy of ultrasonography in detecting medial meniscal tears in group A were 100, 88.9, 96.5, 100, 97.3% and in group B were 83.3, 71.4, 92.6, 50, 81.1%, respectively. The sensitivity, specificity, positive and negative predictive values and accuracy of MRI in group A were 100, 88.9, 96.5, 100, 97.3% and in group B were 96.7, 85.7, 96.7, 85.7, 94.6%, respectively.

Conclusions: Given the fact that the sensitivity and specificity of the results of knee sonography matched that of MRI in patients who were 30 years old or less, we suggest ultrasonography as an effective initial investigation for tears of medial meniscus in this group of patients. Patients with negative ultrasonographic findings will need no further investigation.

Level Of Evidence: Diagnostic studies-investigating a diagnostic test, Level II.