Meniscal Ramp Lesions: What the Radiologist Needs to Know

Diagnostic Accuracy of Magnetic Resonance Imaging in the 120° Flexed-Knee Position for Detecting and Classifying Meniscal Ramp Lesion

BACKGROUND

Detection of meniscal ramp lesions concomitant with anterior cruciate ligament (ACL) injury using conventional magnetic resonance imaging (MRI) has low sensitivity, and these lesions are currently difficult to diagnose preoperatively.

PURPOSE/HYPOTHESIS

The purpose of this study was to assess the accuracy of MRI in detecting the presence of meniscal ramp lesions in the 120° flexed-knee position compared with that in the near-extended-knee position. It was hypothesized that the diagnostic performance of MRI in the 120° flexed-knee position would be better than that in the extended-knee position.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

This retrospective study of prospectively collected data between February 2019 and January 2024 included 154 consecutive patients undergoing ACL reconstruction. All patients underwent 3-T MRI examination in the near extended- and 120° flexed-knee positions preoperatively. The presence and Thaunat classification of ramp lesions were separately detected on each MRI scan and confirmed via arthroscopy during ACL reconstruction. Diagnostic sensitivity, specificity, and conditional relative odds ratios for detecting ramp lesions and the classification accuracy were compared between 2 MRI modalities. The accuracies of these MRI scans in acute and chronic cases were also evaluated.

RESULTS

This study included 154 patients (79 male and 75 female; mean age, 29.0 ± 14.2 years). A total of 62 ramp lesions (40.3%) were observed on arthroscopy. The sensitivity and specificity of MRI in near extension were 69.4% and 77.2%, respectively, and those in flexion were 91.9% and 94.6%, respectively, with significant superiority in MRI at knee flexion (P = .003 and P < .001, respectively). The conditional relative odds ratio between the MRI examinations at these 2 positions was 10.3 (95% CI, 4.82-21.8). The classification accuracy of MRI in flexion was significantly higher than that of MRI in near extension (accuracy, 49 vs 11; P < .001). The diagnostic accuracy of MRI in the 120° flexed-knee position was significantly higher than that in the near-extended-knee position in the acute cases (P < .05); however, no significant differences were observed in the chronic cases.

CONCLUSION

The diagnostic accuracy of MRI in the 120° flexed-knee position for detecting and classifying meniscal ramp lesions was superior to that of MRI in the near-extended-knee position.

Evaluation of the reliability and accuracy of MRI for the diagnosis of meniscal ramp lesions

BACKGROUND

Meniscal ramp lesions are a special type of meniscal injury that affects the periphery of the posterior horn of the medial meniscus and/or its meniscocapsular attachments, strongly associated with anterior cruciate ligament (ACL) tears. Due to their location, these lesions can be missed arthroscopically so it is essential to diagnose them on preoperative magnetic resonance imaging (MRI).

PURPOSE

To evaluate the accuracy of MRI in detecting meniscal ramp lesions in patients with ACL tears using arthroscopy as the reference standard.

MATERIAL AND METHODS

Two musculoskeletal radiologists, blinded to the surgical findings, retrospectively and independently evaluated 106 knee MRI scans for the presence of meniscal ramp lesions in non-consecutive patients who underwent arthroscopic ACL reconstruction between January 2019 and July 2022 by a single surgeon at one institution. Having arthroscopy as reference, the diagnostic sensitivity and specificity as well as the positive and negative predictive values (PPV/NPV) of the MRI scans were calculated. Cohen's kappa coefficient was used to test inter-observer reliability. A P value <0.05 was considered statistically significant.

RESULTS

In the study group of 106 patients (72 men, 34 women; mean age = 33.84 ±13.12 years), 76 had an arthroscopy-confirmed meniscal ramp lesion, while 30 did not. The sensitivity and specificity of MRI for the detection of meniscal ramp lesion were 88% and 87%, respectively. The PPV and NPV were 94% and 74%, respectively. Inter-rater reliability was excellent (k = 0915).

CONCLUSION

This study demonstrates that MRI can accurately detect meniscal ramp lesions.

Reproducibility of MRI in the diagnosis of meniscal ramp lesions: an inter-observer study

BACKGROUND

Meniscal ramp lesions have gained much prominence in recent years due to a significant increase in their diagnosis and their important biomechanical involvement in the knee. A new proposed classification of these lesions has recently been published.

PURPOSE

To evaluate the reproducibility of the new classification of meniscal ramp lesions recently published using magnetic resonance imaging (MRI).

MATERIAL AND METHODS

A total of 249 post-traumatic knee MRI studies were evaluated by three musculoskeletal radiologists independently. Patients with an anterior cruciate ligament (ACL) tear on MRI in addition to a recent history of trauma to the knee for <12 months were included in the study, for a total of 95. We carried out an inter-observer concordance study to analyze whether the new classification is reproducible to detect meniscal ramp lesions and to classify them into their different types.

RESULTS

Among our study cohort of 95 patients, we found 47 (49.5%) ramp lesions. In the inter-observer study, we obtained a good concordance (k = 0.733) in the detection of these lesions and an excellent one (k = 0.843) when the type of lesion is described.

CONCLUSION

This study demonstrates that the new classification of meniscal ramp lesions has good reproducibility on MRI.