MRI characteristics of torn and untorn post-operative menisci

Abstract

Objective To compare magnetic resonance imaging (MRI) characteristics of torn and untorn post-operative menisci. Methods The study group consisted of 140 patients with 148 partially resected menisci who were evaluated with a repeat knee MRI examination and subsequent repeat arthroscopic knee surgery. Two musculoskeletal radiologists retrospectively assessed the following MRI characteristics of the post-operative meniscus: contour (smooth or irregular), T2 line through meniscus (no line, intermediate signal line, intermediate-to-high signal line, and high fluid-like signal line), displaced meniscus fragment, and change in signal pattern through meniscus when compared to baseline MRI. Positive predictive values (PPV) and negative predictive values (NPV) were calculated using arthroscopy as reference standard. Results All 36 post-operative menisci with no T2 line were untorn at surgery (100% NPV), while 46 of 79 post-operative menisci with intermediate T2 line, 16 of 18 post-operative menisci with intermediate-to-high T2 line, and 14 of 15 post-operative menisci with high T2 line were torn at surgery (58.2%, 88.9%, and 93.3% PPV respectively). Additional MRI characteristics associated with torn post-operative meniscus at surgery were irregular meniscus contour (85.7% PPV), displaced meniscus fragment (100% PPV), and change in signal pattern through meniscus (99.4% PPV). Conclusions Post-operative menisci with no T2 signal line were untorn at surgery. The most useful MRI characteristics to predict torn post-operative menisci at surgery were change in signal pattern through meniscus compared to baseline MRI and displaced meniscus fragment followed by high T2 line through meniscus, intermediate-to-high T2 line through meniscus, and irregular meniscus contour.

Functional Outcomes of Arthroscopic Combined Anterior Cruciate Ligament Reconstruction and Meniscal Repair: A Retrospective Analysis

“…The most useful MRI characteristics to predict torn postoperative menisci at surgery were a change in the signal pattern through the meniscus compared with baseline MRI and a displaced meniscal fragment followed by a high T2 line through the meniscus, an intermediate to high T2 line through the meniscus, and an irregular meniscal contour. 20 On the basis of these MRI characteristics, Kijowski et al 20 reported 64 meniscal retears (42.25%) among 148 patients.…”

Good Clinical Success Rates Are Seen 5 Years After Meniscal Repair in Patients Regularly Undertaking Extreme Flexion

“…15 MRI signals at the repair site were assessed on T2-weighted images using the signal characteristics of the grading systems of Kijowski et al. 16 and Crues et al. 17 Degenerative changes on weight-bearing plain radiographs were graded using the Kellgren-Lawrence grading system.…”

“…The absence of a fluid-like signal at the site of repair on proton density or T2-weighted images was considered to indicate a healed meniscus. 16 , 17 …”

“…After informed written consent was obtained, patients were assessed as follows: patient-reported outcome 14 were used to evaluate clinical healing, and magnetic resonance imaging (MRI) scans and radiographs were used to evaluate radiologic healing and outcomes. 15 MRI signals at the repair site were assessed on T2-weighted images using the signal characteristics of the grading systems of Kijowski et al 16 and Crues et al 17 Degenerative changes on weight-bearing plain radiographs were graded using the Kellgren-Lawrence grading system. 18 A trained clinician (J.O.)…”

Posttreatment Imaging of the Knee: Cruciate Ligaments and Menisci

“…Nevertheless, MRI is the preferred imaging modality for assessing patients with persistent or recurrent symptoms after meniscal surgery and may be performed conventionally or with an intra-articular contrast agent. 5 42 43 44 45…”