Summary

The diagnostic accuracy of MRI in detecting RAMP lesions

Abstract

Background

Ramp lesions, longitudinal tears of the posterior horn of the medial meniscus due to meniscocapsular ligament injuries, are increasingly recognized alongside anterior cruciate ligament (ACL) tears1. These lesions compromise the meniscocapsular junction, which stabilizes the tibiofemoral joint under rotational stress2. Untreated RAMP lesions exacerbate joint laxity, undermining ACL reconstruction and accelerating joint degeneration.

Diagnosing RAMP lesions presents challenges, as they are frequently missed on magnetic resonance imaging (MRI). It is an important tool for identifying these lesions, though its sensitivity remains limited, particularly for stable RAMP lesions3,4. Failure to recognize and treat RAMP lesions may lead to persistent joint instability and compromised postoperative outcomes, underscoring the need for reliable diagnostic strategies.

Objectives

The primary objective of this study was to evaluate the diagnostic accuracy of MRI in detecting RAMP lesions, with a focus on sensitivity, specificity, and predictive values.

Methods

This retrospective study included patients who underwent MRI scans for suspected ACL tears or ruptures between 2019 and 2021 at a London hospital. MRI reports were reviewed to assess whether RAMP lesions were identified or if secondary features indicative of RAMP lesions were present. These features included meniscocapsular separation, posteromedial bone marrow edema, and fluid in the posteromedial capsule. Arthroscopic findings were used to confirm the presence of RAMP lesions, as the gold standard investigation.

Results

A total of 330 MRI scans were reviewed, 104 of which involved ACL ruptures. Of these, 33 cases did not have arthroscopic evaluation. Among the remaining 71 cases, 48 MRI scans mentioned indications of a RAMP lesion. The sensitivity of MRI for detecting RAMP lesions was 56.3%, with a specificity of 88.5%. When secondary features such as meniscocapsular separation, tibial posteromedial bone bruising, and posteromedial edema were included, the combined sensitivity was 55.6%, and specificity was 59.6%, resulting in a negative predictive value of 88.6%.

Discussion

This study demonstrated that MRI has limited sensitivity in detecting RAMP lesions, especially when relying on detection of the lesion. However, incorporating secondary features significantly improved diagnostic utility, with a high negative predictive value, suggesting that the absence of these signs could reliably exclude RAMP lesions.

The limitations of this study include its retrospective design and the small patient cohort, which may limit the generalizability of the findings. Variability in arthroscopic documentation and imaging interpretation by surgeons also presents a challenge. Future research should employ prospective designs, involving MRI interpretations by musculoskeletal radiologists and systematic arthroscopic evaluations using standardized classifications. Developing clinical algorithms that integrate clinical, radiological, and arthroscopic findings may further improve diagnostic accuracy and treatment outcomes.

References

Chahla J, et al. Meniscal ramp lesions: anatomy, incidence, diagnosis, and treatment. Orthop J Sports Med. 2016;4(7):2325967116657815.

Stephen JM, Halewood C, Kittl C, Bollen SR, Williams A, Amis AA. Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity. Am J Sports Med. 2016 Feb;44(2):400-8. doi: 10.1177/0363546515617454. Epub 2015 Dec 11. PMID: 26657852.

M. Laurens;E. Cavaignac;H. Fayolle;R. Sylvie;F. Lapègue;N. Sans;M. Faruch; (2021). The accuracy of MRI for the diagnosis of ramp lesions . Skeletal Radiology, (), –. doi:10.1007/s00256-021-03858-w

Greif, Dylan N.; Baraga, Michael G.; Rizzo, Michael G.; Mohile, Neil V.; Silva, Flavio D.; Fox, Terry; Jose, Jean (2020). MRI appearance of the different meniscal ramp lesion types, with clinical and arthroscopic correlation. Skeletal Radiology, (), –. doi:10.1007/s00256-020-03381-4