The technique of vibration arthrography (VAG) permits the non-invasive evaluation of internal derangements of the knee. Using the computer-assisted recording and analysis equipment which has previously been described, a major survey was conducted into the signal patterns present in subjects with symptomatic knee joints. Two hundred and forty-seven patients were examined, and all of these subsequently underwent arthroscopy. One hundred and seventy-two patients were demonstrated arthroscopically to have a meniscal lesion and 150 of these gave characteristic meniscal signals. This paper discusses the vibration signal patterns associated with the various types of meniscal tear and the effect of surgery on the meniscal signal. The overall accuracy of vibration arthrography in the diagnosis of meniscal pathology was 86%. In many cases, not only could the site of a meniscal tear be determined, but the type of tear could be diagnosed with reasonable accuracy.