Posterior Displacement of Meniscal Ramp Lesion Is Observed on Flexed Knee Magnetic Resonance Imaging of Anterior Cruciate Ligament-Deficient Knees

A nosographic and etiopathogenetic framework for subchondral bone marrow lesions in the knee: A narrative review

Purpose

Subchondral bone marrow lesions (BMLs) are present in a wide range of pathologies with different prognoses. Thus, a careful diagnosis is mandatory to address them with the proper treatment. The aim of this review was to examine BMLs aetiology and their relationship with biomechanical and biological factors, to identify BMLs and help clinicians to properly recognize and treat each of these common alterations.

Discussion

Each pathological pattern is determined by different aetiologic factors, which may act alone or synergically in determining the BML. These factors include major or minor trauma, bone tissue alterations, altered joint load distribution, coagulopathies, and hormonal alterations. This narrative review encompasses these patterns and factors providing a nosographic and etiopathogenetic framework for subchondral BMLs in the knee.

Conclusion

While the field is still heterogeneous in the definition of the nosographic framework of BMLs, there is a trend with the convergence towards a common terminology, which could help to shed more light on the complex and varied field of BMLs. Future studies should focus on better understanding the etiopathogenetic mechanisms, which can concur with the development of BML from one side, and, on the other hand, may represent targets for future treatments to address BMLs and preserve or restore the osteochondral unit.

Level of Evidence

Expert Opinion, Level V.

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.

Arthroscopy Honors 2025 Award-Winning Authors Across Diverse Platforms

With sincere appreciation to the Arthroscopy Association of North America Education Foundation for their support, we present Arthroscopy's 2025 Annual Awards for the best Clinical Research, Basic Science Research, Resident/Fellow Research, Systematic Review, and Podcast published in 2024, as well as the Most Downloaded and Most Cited papers published 5 years ago in Arthroscopy, and the Most Downloaded Arthroscopy Techniques article. In addition, as of January 1, 2025, we have updated our Editor-in-chief, Assistant Editor, and Deputy and Associate Editors disclosures of potential conflicts of interest as well as our journal masthead.

Editorial Commentary: A Gap-Based Subclassification of Ramp Lesions Has the Potential to Enhance Treatment Precision and Patient Outcomes in Anterior Cruciate Ligament-Deficient Knees Subtitle: Customizing Solutions for Anterior Cruciate Ligament-Deficient Knees

Our evolving understanding of ramp lesions has significantly affected the field of anterior cruciate ligament injury and meniscal repair. Although these lesions have been linked consistently to increased anterior and rotational instability in anterior cruciate ligament-deficient knees, there remains a contentious debate regarding their optimal treatment. The current literature is divided, as some advocate for surgical repair of only arthroscopically unstable lesions. Others point to a substantial risk of complications, noting a 28.6% incidence in untreated stable lesions, and thus advocate for surgical repair of all lesions. Through the use of magnetic resonance imaging scans of flexed knees, a novel subclassification of ramp lesions based on gap distance at the tear site shows a correlation with posterior capsular displacement, anterior laxity, lesion size, and joint effusion. This nuanced classification offers new insights and promises to refine treatment decisions, potentially minimizing unnecessary surgeries and improving patient outcomes.