Imaging the postoperative meniscus

These guidelines provide a basis for interpretation that the authors have found works well. In general, when faced with the interpretation of a standard MR examination in a patient who has had meniscal surgery, the authors look for unequivocal sites of fluid-intensity signal within the meniscal remnant as the only reliable signal criteria for a new tear. The authors accept almost any contour change or signal intensity within the remnant as normal unless a sharp edge or free fragment is detected. They use standard criteria to interpret areas of the menisci known to be separated from the site of prior surgery. When there is prior knowledge of significant meniscal resection, prior knowledge of meniscal repair, or nonspecific knowledge of prior surgery with new symptoms in the same area as the initial symptoms, MR arthrography is used. The authors have found that MR arthrography is of additional value in assessing the articular cartilage. Because cartilage is known to deteriorate more rapidly after meniscectomy, it is often appropriate to use MR arthrography to visualize the meniscal remnant and cartilage together, because either or both may be the cause of the patient's new symptoms.