I am watching the DVD the surgeon gave me after doing knee surgery on me to fix a torn ACL. There’s quite a bit of time taken up looking for a “ramp lesion.” Evidently, I don’t have this problem but there was nothing said to explain what it is. Can you tell me what the surgeon was looking for and why?

Surgeons treating patients with anterior cruciate ligament (ACL) tears are always advised to look for damage to other knee structures during the arthroscopic exam. One of those potential soft tissue injuries is a ramp lesion.

What’s a ramp lesion? It involves the medial meniscus, a C-shaped piece of thick cartilage inside the knee. There are two of these protective liners: medial (side closest to the other knee) and lateral (side away from the other knee).

Tears of the medical meniscus are common with ACL injuries. A ramp lesion is a special type of medial meniscus tear that hasn’t been studied as much as other types of meniscal tears.

A ramp lesion occurs when one particular edge of the medial meniscus (near the posterior or back portion of the cartilage) comes loose. The tear is located where the meniscus meets the synovium (lining of the knee joint). It is usually a lengthwise or longitudinal tear.

Normally, the posterior horn of the medial meniscus is a difficult structure to see even with an arthroscope. Tight joints with little laxity keep this portion of the meniscus out of sight. But with ligamentous laxity (such as occurs when the anterior cruciate ligament is torn) makes it possible not only to see this portion of the medial meniscus, but also to check it for tears or ramp lesions.

It occurs most likely as a result of increased torsional (twisting) and shear forces of the tibia (lower leg bone) as it moves against the femur (thigh bone). Anytime the ACL is torn or stretched too much, the tibia can slip and slide more than it should underneath the femur. That’s when the back edge of the meniscus is most likely to crack, tear, and/or pull away from the bone.

Studies have shown that removing damaged or torn menisci (plural for meniscus) isn’t a good idea. Patients with missing menisci end up with joint arthritis. Repairing the damage provides much better long-term outcomes. Small ramp lesions may not need surgical repair, whereas, larger lesions may need to be sewn back down to allow for complete healing. Further studies are needed to confirm these finding before firm recommendations can be made.