Meniscal ramp lesions are lesions that occur with an ACL injury and lead to damage of the meniscus in the periphery of its posterior segment. This would be the back inner corner of the medial aspect of the knee. These tears will disrupt the attachment between the posterior medial meniscus and the surrounding knee joint capsule.
Ramp lesions have been colloquially termed the “hidden lesion” because they were historically under-recognized. This is in part due to the fact that the tear is located in a portion of the knee termed the “blind-spot.” After an ACL rupture, the knee will have some level of instability in multiple directions. In this situation, the meniscus plays an even larger role in maintaining stability within the knee. Moreover, studies have shown that an ACL reconstruction will be biomechanically inferior to a normal knee if a significant ramp lesion is present but not repaired. While this might be true in a laboratory setting, it is unclear if this remains true in a real-patient context.
How are ramp lesions diagnosed and treated?
Ramp lesions are unique relative to other meniscal injuries as MRI is not effective at identifying these lesions preoperatively. This is a situation where directly visualizing the posteromedial corner, or the “blind-spot,” of the knee with an arthroscope (camera) is needed. Currently, it is unclear if ramp lesions require repair or if they can be treated non-operatively. For lesions where there is an ACL deficiency, ramp lesions are typically repaired to maximize stability of the knee. For other cases, non-operative approaches may be superior. The peripheral location of a ramp lesions means they have good healing potential with good blood supply. Some believe that smaller, less symptomatic lesions can be left alone to spontaneously heal. For larger lesions, meniscal repair with surgery may be the best option and has a good success rate.