Medial meniscus RAMP lesions: a novel magnetic resonance arthrography-based classification

Meniscal ramp lesions (RAMP) are longitudinal tears at the meniscocapsular or meniscotibial attachments of the posterior horn of the medial meniscus, commonly associated with anterior cruciate ligament (ACL) tears. Their preoperative detection on standard MRI remains limited, especially for "hidden" variants. Magnetic resonance arthrography (MRA) may theoretically enhance visualization of the posteromedial compartment through capsular distension and improved tissue contrast; however, its diagnostic superiority remains to be validated. This pictorial review introduces a conceptual MRA-based framework for describing ramp lesions (types A-E), derived from previously reported anatomical and imaging concepts in the literature and illustrated with representative institutional cases. The proposed framework emphasizes lesion topography, morphology, and contrast-medium behavior on MRA and is intended as an educational and hypothesis-generating model rather than as a validated diagnostic tool. Further studies with arthroscopic correlation, reproducibility assessment, and prospective validation are needed to determine the diagnostic and clinical value of this framework.