Ramp lesion (meniscus)

Ramp lesions are defined as a vertical (longitudinal) tear of the peripheral capsular attachment of the posterior horn medial meniscus at the meniscocapsular junction ¹. As it is a minor injury and has a hidden location using standard anterolateral and anteromedial arthroscopic portals, its identification guides the orthopedic surgeon to identify it on arthroscopy by probing of the posterior horn of the medial meniscus, which may require an additional portal ³. 

Epidemiology

In ACL-deficient knees, the incidence is reported at ~12.5% (range 9-17%) ³. 

Pathology

Ramp lesions most frequently occur in the setting of a pivot shift mechanism of injury (e.g. anterior cruciate ligament (ACL) injuries) ². It is suggested to be due to disruption of the meniscotibial ligaments, or as a result of a tear of the peripheral attachment of the posterior horn of the medial meniscus ².

Associations

The presence of ramp lesions is associated with ^{3, 6}:

• ACL rupture
• ACL graft failure
• increased risk of developing osteoarthritis

Radiographic features

MRI

Ramp lesions appear as an abnormal signal at the peripheral most portion of the posterior horn of the medial meniscus. They can be difficult to identify if there is little or no posterior meniscocapsular tissue separation. 

The most specific signs are complete thin linear fluid signal between the posterior horn of the medial meniscus and posteromedial capsule and posterior meniscal irregularity ³. Posteromedial tibial plateau marrow edema may be present as an additional indicator of a ramp lesion ⁶.

Treatment and prognosis

If unstable, ramp lesions can be repaired arthroscopically ⁶.