Meniscus tear — clinical guide— full professional article

What is the meniscus?

The meniscus is a fibrocartilaginous structure that sits around the periphery of the knee. Each knee has two menisci.

Medial meniscus (inner side).

Lateral meniscus (outer side).

Meniscal tissue is rubber-like and has the shape of an almost complete ring.

The meniscus has several roles in the knee, including load distribution across the joint, nutrition of the articular cartilage, shock absorption, and more.

In short, the menisci are essential for normal structure and function of the knee cartilage.

Anatomically, the meniscus is often divided into an anterior horn, a body, and a posterior horn.

What is a meniscal tear, and what types exist?

A meniscal tear is, as the name implies, a tear in meniscal tissue. A tear may involve any part of the meniscus, in any plane and configuration.

Tears are broadly classified as traumatic tears versus degenerative tears.

A traumatic tear occurs in an otherwise structurally normal knee after injury.

A degenerative tear occurs in a knee with underlying degenerative changes—that is, cartilage wear or a worn meniscus even when cartilage loss is not yet advanced. Younger patients more often have traumatic mechanisms, whereas older adults more often have degenerative patterns.

How does a meniscal tear occur?

A traumatic tear typically follows an injury, often a forceful twisting mechanism (football is a classic example).

A degenerative tear may also occur after twisting, but far less energy is required to tear worn meniscal tissue.

In many cases there is no clear traumatic event—patients report pain that appeared “for no reason.”

Why does a torn meniscus hurt?

The body has pain receptors. Unstable, torn, or partially detached tissue can generate pain—for example, a partially avulsed nail or a skin flap that still attaches on one edge hurts with movement.

Similarly, torn meniscal tissue becomes mechanically unstable and painful whenever it is loaded or moved.

What is a bucket-handle tear?

A bucket-handle tear is a longitudinal traumatic tear that runs from the anterior horn through the body to the posterior horn, while the anterior and posterior roots often remain attached. The torn segment displaces into the joint, creating a “handle” appearance.

Because the fragment tends to move centrally, it frequently causes mechanical locking—that is, it blocks full extension so the knee cannot fully straighten.

What is a locked knee?

A locked knee means passive full extension cannot be achieved for a mechanical reason—something in the front of the joint blocks terminal extension.

The blocker may be a loose body, a bucket-handle meniscal fragment, torn ligament stump, foreign material, or other pathology.

What is a meniscal root tear?

The meniscus anchors to the tibia at the anterior and posterior roots—the posterior root attachment is the one most commonly injured in root tears.

A root tear is essentially avulsion of the root from bone: the meniscus is no longer anchored and is extruded from the joint, functionally similar to a knee without a meniscus—comparable to total meniscectomy.

What are the implications of a meniscal root tear?

Because the knee behaves as if the meniscus is absent, two major concerns dominate:

Accelerated degenerative wear of the articular cartilage.

Insufficiency fracture patterns around the knee.

What is an insufficiency fracture around the knee?

Without meniscal load sharing, focal areas of the joint surface may be exposed to stresses they cannot withstand, leading to collapse—not a classic traumatic fracture but a subchondral insufficiency / compression injury under the cartilage.

Insufficiency fracture is often identified together with a posterior root tear, which is frequently the driving mechanism.

What is a discoid meniscus?

A normal meniscus is C-shaped, like a crescent moon.

A small percentage of people have a meniscus that is not crescent-shaped but more like a complete disc—full or partial disc morphology.

Another variant considered discoid is incomplete peripheral attachment to the joint capsule.

Discoid morphology can affect either meniscus but is most common laterally.

A discoid meniscus is often asymptomatic by itself.

It becomes clinically relevant when torn or when hypermobile meniscal tissue causes mechanical symptoms such as lateral “clunking.”

How is a meniscal tear diagnosed?

As in all of medicine, evaluation begins with history: mechanism, pain location, mechanical symptoms, aggravating and relieving factors, prior treatments, and functional goals.

The second step is physical examination.

Imaging follows; MRI is the standard study for suspected meniscal tears.

How are meniscal tears treated?

Treatment may be non-operative.

Or operative.

Non-operative care emphasizes structured physiotherapy.

Operative treatment is knee arthroscopy.

In this minimally invasive procedure, a camera and instruments are introduced through small anterior knee portals.

The surgeon systematically inspects the compartments and meniscal tissue on a monitor.

When a tear is confirmed, surgeons generally address it in one of two ways:

Partial meniscectomy—removing the unstable torn fragment that drives symptoms.

Meniscal repair (suture repair), reserved for selected tear patterns and patients.

Repair decisions depend on shared decision-making. Common factors favoring repair include:

Younger age—repair is favored more in younger patients.

Peripheral tear location—more vascular “red-zone” pattern favors healing.

Tissue quality—healthier tissue favors repair.

Acute tears—fresher injuries generally heal better.

ACL reconstruction in the same setting—meniscal healing environment may improve, biasing toward repair when appropriate.

The meniscus has limited blood supply; nutrition is largely from synovial fluid. Peripheral perfusion declines with age, which lowers healing potential.

Even when repair is chosen, healing failure remains possible; symptoms may recur and repeat arthroscopy with partial meniscectomy may be required.

Is arthroscopy mandatory for every meniscal tear?

No—absolutely not.

There is no obligation to operate for an MRI diagnosis alone.

Surgery is reasonable when symptoms justify intervention and shared goals align with operative risk.

Mechanical locking from a bucket-handle tear is a common indication to restore full extension and range of motion.

How is a meniscal root tear treated?

This is a special situation: functionally the knee behaves as if meniscus-deficient. Strong consideration is given to anatomic root repair and re-approximation to bone to restore load sharing, protect cartilage, and reduce insufficiency fracture risk.

Because repair is to bone with richer blood supply, healing potential is more favorable than for many mid-substance tears.

There is therefore rarely a strict age ceiling for root repair—though advanced arthritic change may make repair futile.

In end-stage degenerative knees, root repair may not be appropriate.

Does arthroscopy cause knee arthritis?

Less healthy meniscal tissue generally means higher long-term risk of degenerative change.

A torn meniscus is already mechanically compromised; over time, wear rates may exceed knees without tears, with or without surgery.

Goals of surgery:

Improve quality of life by reducing pain—either by removing unstable tissue or by repairing when criteria are met.

Preserve joint biology when repair is feasible to lower future cartilage wear risk.

In summary, partial meniscectomy targets symptomatic unstable fragments; future cartilage risk relates to the underlying tear biology, not the operation alone.

What is a discoid meniscus (revisited)?

A discoid meniscus resembles a disc or coin rather than a crescent—it lacks the typical anterior horn–body–posterior horn pattern and instead forms a thickened discoid plate.

It is a congenital variant; the lateral side is overwhelmingly more common than medial.

Most discoid menisci are asymptomatic.

When does a discoid meniscus become symptomatic?

It usually becomes symptomatic when torn.

Some hypermobile discoid menisci lack stable peripheral attachments, “shuttling” in the joint and producing clunking; patients may feel or even hear the motion.

What is the treatment for a discoid meniscus?

Asymptomatic discoid menisci require no treatment.

Symptomatic tears are managed like other meniscal tears affecting quality of life.

Symptomatic hypermobile discs are often treated arthroscopically by saucerization to a more normal C-shape, sometimes with peripheral stabilization sutures to the capsule.