Can a meniscal root tear be missed on an MRI?

Why root tears are easy to miss

The root is only a short segment of the meniscus where it attaches to bone. On standard MRI slices it may appear on just one or two images, and in an older knee it can be mistaken for general wear. A report may describe degeneration or a small tear without naming the root.

Signs a surgeon looks for

• Extrusion: the body of the meniscus sitting partly outside the edge of the shin bone on the front-on images
• A ghost sign: the meniscus seems to vanish on a slice where it should be visible
• A vertical gap or cleft right next to the root on the front-on images
• A radial tear very close to the root on the side-on images
• Bone bruising or a small stress fracture in the bone beneath the inner cartilage

No single sign is decisive, so the images are interpreted together with the story and examination.

The clinical clues matter too

A typical history is a pop at the back of the knee during a deep bend, followed by inner knee pain, in someone in their 40s to 60s. On examination there is often tenderness at the back of the inner joint line and pain with deep squatting. If this picture fits but the report is reassuring, it is reasonable to ask a knee surgeon to look at the images themselves, not just the written report.

When a repeat scan or second look helps

If the first MRI was done very early, on a lower-strength machine or without the right sequences, or if symptoms change suddenly, a repeat scan may be useful. In the operating theatre, arthroscopy shows the root directly, but surgery is not used simply to diagnose.

Dr. Gelber reviews the actual MRI images for patients in Qatar, including scans done at other centres. Bring standing X-rays too if you have them.