Glossary
Meniscal extrusion
Quick answer
Meniscal extrusion means the meniscus has been pushed outwards beyond the edge of the shin bone, so part of it no longer sits between the bones to absorb load. It often points to a root tear or arthritis, says Doha knee surgeon Dr. Pablo Gelber, who reviews these scans at Aman Hospital.
What it means
A healthy meniscus sits neatly on the rim of the tibia. On a front-to-back MRI slice the radiologist measures how far it bulges past that rim, usually in millimetres. A few millimetres of extrusion, commonly around three or more, is generally regarded as significant.
Extrusion is a sign, not a diagnosis. It shows that the meniscus has lost the hoop tension that normally holds it in place.
Why it matters
When the meniscus is extruded, the cartilage of the femur and tibia carries more of the load directly. Over time this speeds up wear and may lead to bone marrow swelling or a subchondral insufficiency fracture.
Common causes include a meniscal root tear, a complete radial tear, and established osteoarthritis. In a younger person with a fresh root tear, extrusion is a reason to act sooner; in advanced arthritis it is usually part of the overall picture.
How it is managed
Treatment targets the cause. A repairable root tear may be fixed back to bone, sometimes with a centralisation stitch to pull the meniscus back in. Where arthritis is the driver, care focuses on strengthening, weight management, alignment and, if needed, osteotomy or replacement.
Frequently asked questions
Can an extruded meniscus go back into place?
It does not usually move back by itself. Surgery to repair a root tear, sometimes with centralisation, can reduce extrusion in suitable patients.
Is meniscal extrusion the same as a tear?
No. Extrusion describes the meniscus position. It is often caused by a tear, especially at the root, but the report will describe any tear separately.
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