Is there a role for sonography in the diagnosis of tears of the knee menisci?

PURPOSE The aim of this study was to investigate the usefulness of sonography in diagnosing tears of the knee menisci. METHODS In this retrospective study, we reviewed the sonographic examinations of the knees of 321 patients diagnosed with a torn meniscus on the basis of clinical findings. Of the 321 knees imaged, 216 were also examined using MRI or CT. Arthroscopic meniscectomy was performed on 126 knees. RESULTS MRI or CT did not confirm 48% (71 cases) of the positive sonographic diagnoses (ie, false positives) and 72% (50 cases) of the negative sonographic diagnoses (ie, false negatives). Thus, the sonographic diagnosis was correct in 95 cases (44%) and incorrect in 121 cases (56%), yielding low rates of sensitivity (60%) and specificity (21%). Among the 126 cases in which arthroscopic meniscectomy was performed, arthroscopy confirmed 100% of the MRI or CT diagnoses of meniscal tears. CONCLUSIONS Our results indicate that sonography is not accurate enough to be used as the only imaging modality for diagnosing tears of the knee menisci.