The value of ultrasonography in the detection of meniscal tears diagnosed by magnetic resonance imaging.

Abstract

To evaluate the diagnostic value of ultrasonography in meniscal tears that were diagnosed by magnetic resonance imaging (MRI). Twenty-seven knees with meniscal tears and 14 knees without tears on MRI were prospectively evaluated. A radiologist performed the ultrasonography and evaluated the presence and locations of the meniscal tears. MRI was used as the reference standard. Twenty-nine menisci with tears and 53 menisci without tears were identified by MRI. Twenty-two tears were in the medial menisci, and seven tears were in the lateral menisci. In the 29 meniscal tears, the ultrasonographic diagnosis was correct in 25 (86.2%) and incorrect in 4 (13.8%) menisci. In the 53 menisci without tears, the ultrasonographic diagnosis was correct in 45 (84.9%) and incorrect in 8 (15.1%) menisci. Ultrasonography showed a sensitivity, specificity, accuracy, and positive and negative predictive values for meniscal tears of 86.2%, 84.9%, 85.4%, 75.8%, and 91.8%, respectively. Of the four intracapsular injuries observed by MRI in injured knees, an osteochondritis dessecans was only observed by ultrasonography. Ultrasonography is an accurate imaging study for diagnosing meniscal tears. The results correlated with those obtained by MRI; this suggests that ultrasonography can be a useful imaging modality in uninjured knees.