Meniscus tears

Each knee has two menisci — wedge-shaped pieces of fibrocartilage between the femur (thigh bone) and tibia (shin bone), one on the inner side of the knee and one on the outer side. You can think of them as shock absorbers: they distribute load, absorb forces, and contribute to knee stability.

Because the menisci help spread and absorb the forces that pass through the knee, they are part of what allows the joint to handle walking, squatting, running, and pivoting comfortably over a lifetime.

Traumatic tears often occur during a twisting or pivoting injury, frequently in younger or active patients. Degenerative tears develop in tissue that has changed over time and may occur after a minor movement or without a distinct injury.

Knowing roughly which kind of tear is involved is one part of the picture your surgeon puts together — it is not, on its own, what decides treatment.

Symptoms may include joint-line pain, swelling, stiffness, difficulty fully bending or straightening the knee, and catching or locking. Symptoms vary, and an MRI finding does not necessarily mean that the tear is causing a patient's pain.

• Joint-line pain, often on the inner or outer side of the knee
• Swelling
• Stiffness
• Difficulty fully bending or straightening the knee
• Catching or locking

Catching, clicking, or locking can occur with a meniscus tear, but these symptoms alone do not establish the diagnosis or determine whether surgery is needed.

One situation is worth acting on sooner: a knee that is mechanically locked and cannot fully straighten warrants prompt evaluation.

Evaluation begins with the history and physical examination. X-rays assess the bones, alignment, joint spacing, and arthritis. MRI provides more detail about the meniscus, cartilage, ligaments, and other soft tissues.

Imaging findings are interpreted together with the examination and symptoms, rather than on their own — which is why an MRI finding does not automatically mean the tear is the source of a person's pain.

Many meniscus tears — particularly degenerative tears — can be managed without surgery. Treatment may include activity modification, physical therapy, medication or other measures for pain and swelling, and sometimes an injection.

Surgery may be considered when persistent symptoms interfere with activities or when the tear's characteristics make operative treatment appropriate. The right path is individual and is decided together with your surgeon after understanding the trade-offs.

When surgery is considered, there are two broad approaches with different goals: a meniscus repair, which stitches the torn tissue so it can heal and preserves the meniscus, and a partial meniscectomy, which trims away only the damaged, non-repairable tissue while keeping as much healthy meniscus as possible.

Whether a tear can be repaired depends on its pattern, location, tissue quality, blood supply, chronicity, and associated injuries. Repairability sometimes cannot be determined definitively until the tear is evaluated arthroscopically.

Preserving as much functional meniscus as possible is a priority. Loss of meniscal tissue increases stress on the articular cartilage and can contribute to the later development or progression of arthritis.

This is why, when a tear can be repaired, preserving the meniscus is generally preferred — and why, when tissue must be removed, the goal is to remove only what is damaged and keep the rest. It's one of the things worth discussing with your surgeon in the context of your own knee.