Meniscus Tear on MRI: Imaging Findings

What your report says: meniscal signal grade 1, 2 or 3

Report wording you may see

• “Grade 2 intrasubstance signal in the posterior horn of the medial meniscus”
• “Intrasubstance degeneration of the meniscus without a discrete tear”
• “Linear signal contacting the inferior articular surface”
• “Grade 3 signal consistent with a tear”

What the grades do and don't mean

• Grade 1 is a rounded spot of signal and grade 2 a line of signal. In studies comparing MRI with meniscus tissue, both matched degeneration of the tissue rather than a tear.
• Grade 3 signal touches the joint surface of the meniscus. Many radiologists only call a tear when this is seen on at least two images, because a single image is less reliable.
• Meniscal findings become common with age: in a large community study of people aged 50 to 90, most of those with a meniscal tear on MRI had no knee pain in the previous month.

When it tends to matter

Grade 1 or 2 signal on its own is not a tear, so it rarely drives treatment by itself. When grade 3 signal is reported, the tear's pattern, its location and any displaced fragment are the details your doctor weighs together with your symptoms and examination.

Questions for your doctor

• Is the signal grade 2 or grade 3, and on how many images does it reach the surface?
• Which part of the meniscus is affected: the anterior horn, the body or the posterior horn?
• Could this finding explain my symptoms, or is it more likely age-related?
• Would my treatment change if this were called a tear?

Meniscal tears are among the most common knee injuries, affecting both athletes and older adults. The menisci serve as shock absorbers between the femur and tibia, and tears can cause pain, swelling, and mechanical symptoms.

For how each tear pattern behaves, see meniscus tear types explained; a meniscal tear can also feed fluid into a Baker's cyst behind the knee.