Lateral Meniscus of the Knee: What It Is and How a Tear Manifests

The lateral meniscus is a cartilage pad between the bones of the knee joint that acts as a shock absorber and stabilizer. A tear of this structure is one of the most common closed knee injuries. Below is a calm breakdown: where it is located, how it differs from the medial meniscus, how a tear manifests, and what examinations doctors use.

What the lateral meniscus is and where it is located

The meniscus is a cartilage pad that serves as a shock absorber in the joint and stabilizes the knee joint. During movement, the menisci compress and change shape. There are two menisci in the knee: the outer (lateral) and the inner (medial). At the front of the joint, they are connected by the transverse ligament. The lateral meniscus is located on the side of the fibula. On the sides of the joint, the menisci are fused with the capsule and receive blood supply from the capsule's arteries, while the inner parts have no blood supply of their own and are nourished by intra-articular fluid.

How the lateral meniscus differs from the medial

The lateral meniscus is more mobile than the medial, so traumatic injuries to it occur less frequently. The medial meniscus is less mobile and is connected to the medial collateral ligament of the knee joint—which is why it is often injured together with the ligament. Within the meniscus, three zones are distinguished: the peripheral (red) zone at the junction with the capsule, the intermediate (red-white) zone, and the central—white, or avascular—zone. The closer a tear is to the inner edge, the fewer vessels are nearby and the lower the likelihood of healing.

How a lateral meniscus tear occurs

Meniscal tears are the most common injury of the knee joint among all closed injuries and one of the most common types of sports injuries. They occur during sharp movements of the lower leg with rotation in the knee joint but with a fixed foot. Less commonly—during squats and jumps. Often the injury that led to the tear is minor: it is enough to twist the knee while standing up. Tears are divided into traumatic (excessive load on an unchanged meniscus) and degenerative (normal load on an altered meniscus).

What symptoms indicate meniscal damage

Immediately after the injury, pain of varying intensity occurs in the knee, and the knee swells. A torn fragment may interfere with movement, and with a bucket-handle tear, it may become entrapped between the articular surfaces and cause joint locking: sudden sharp pain and restricted movement. When the injury is in the red zone, blood accumulates in the joint cavity (hemarthrosis)—swelling slightly above the patella. In the initial stage, symptoms resemble other knee conditions, and only after 2–3 weeks, when reactive phenomena subside, can one speak specifically of a tear. Typical signs:

• pain or tenderness in the knee that worsens with physical activity;
• stiffness and swelling around the knee—it may not appear immediately but after several hours or days;
• difficulty bending, extending, or moving the knee, or going up and down stairs;
• a feeling that the knee gives way when trying to stand up;
• crunching or clicking when moving the knee.

How a tear is diagnosed: examination, MRI

To rule out damage to bone structures, X-rays are taken. Meniscal tears themselves are not visible on them: the menisci are transparent to X-rays. More modern methods are magnetic resonance imaging and endoscopic arthroscopy. The doctor assesses the mechanism of injury, knee movements, and imaging data.

When to see a doctor

Most symptoms of a meniscal tear are not dangerous, but sometimes medical help is needed. See a doctor if knee pain interferes with usual activities or sleep, worsens or returns, symptoms do not improve after home conservative measures, and the knee remains stiff for more than 30 minutes after waking. Urgent consultation is needed if after a fall or injury the pain is very severe, you cannot walk or bear weight on the leg, the skin around the knee is swollen and hot, there is pain and high fever or chills, or the leg cannot be bent or extended.

A meniscal injury by itself is not a reason to call an ambulance. Call 103 or 112 if the knee has shifted, changed shape, or is at an unnatural angle, as well as with numbness or loss of sensation in the knee, leg, or toes.

A meniscal tear can heal on its own, but it takes time; sometimes doctors discuss physical therapy, and for severe damage—arthroscopy. Actual timelines vary for everyone, and only a doctor can give an honest prognosis after examination and imaging. This material is for reference and does not replace a doctor's consultation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer