Lateral meniscus tear

A lateral meniscus tear happens when the cartilage cushioning the outer part of your knee tears, often from a sudden twist or years of gradual wear. This injury can cause pain, swelling and a knee that catches or locks when you move. With the right treatment, most people recover well and get back to their normal activities.

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Illustration of a human knee joint with labeled parts including quadriceps, femur, patella, and ligaments.

Anatomy of the knee

Your knee relies on two crescent-shaped pieces of cartilage called menisci to absorb shock and keep the joint stable. The lateral meniscus sits on the outer side of the knee, between the thighbone and shinbone, where it cushions the joint and helps distribute your body weight evenly during movement.

Because the lateral meniscus supports so much of the knee's stability, a tear here can affect how the joint bends, twists and bears weight. Depending on the tear's size and location, it may cause anything from mild discomfort to significant instability.

Overview

Symptoms

A lateral meniscus tear can cause symptoms right away or develop gradually over time. Common signs include:

Pain on the outer side of the knee
Swelling that develops within a day or two of injury
A popping sensation at the time of the tear
Knee stiffness or difficulty fully straightening the leg
Catching or locking of the knee joint
A feeling that the knee is giving way

Symptoms may ease with rest at first, but they often return or worsen with activities like squatting, twisting or climbing stairs.

Causes

A lateral meniscus tear can result from a sudden injury or gradual wear over time. Common causes include:

Twisting or pivoting the knee while the foot stays planted
Deep squatting or kneeling
Direct impact during sports or physical activity
Age-related thinning of the cartilage, which can make the meniscus more prone to tearing during everyday movements

In some cases, a tear can occur without an obvious injury, especially in older adults with naturally worn cartilage.

Risk factors

Certain factors can increase your likelihood of a lateral meniscus tear, though having one or more of these does not mean you'll develop this condition:

Participating in sports that involve pivoting or sudden stops, such as basketball, soccer or tennis
Jobs or activities that require frequent squatting or kneeling
Prior knee injuries
Age-related changes in cartilage strength and flexibility

Knowing your risk factors can help you and your care team make informed decisions about activity and prevention.

Diagnosis

Diagnosing a lateral meniscus tear typically starts with a discussion of your symptoms and how the injury occurred, followed by a physical exam to check your knee's range of motion, stability and areas of tenderness. Imaging tests can confirm the diagnosis and help determine the best course of treatment. Common tests include:

X-rays, which help rule out fractures or arthritis
MRI scans, which provide detailed images of the meniscus and surrounding soft tissue to show the location and severity of the tear

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Our board-certified specialists are here to help you heal. They can often diagnose the problem in one visit and get you started with a personalized treatment plan. We offer a wide variety of treatment options.