Meniscus injuries are among the most common knee problems that people face, affecting athletes and older adults alike. These tears in the rubbery cartilage that cushions your knee can happen suddenly during sports or gradually develop over time as the body ages.

Understanding Meniscus Injury Statistics

Meniscus tears represent a very common knee injury that affects people across all age groups and activity levels. According to statistics from the United States, meniscal tears affect approximately 61 out of every 100,000 people each year.^[2] This makes it one of the most frequently encountered knee injuries that healthcare professionals treat.

The injury is particularly common among athletes and people who participate in sports activities. When people talk about having torn cartilage in their knee, they are usually referring to a torn meniscus.^[3] However, this condition doesn’t only affect the young and active. Older adults are also significantly affected by meniscus tears, though often for different reasons than younger people experience.

Sports-related meniscus injuries often occur alongside other knee injuries, making the situation more complex. For example, tears of the anterior cruciate ligament (ACL), which is a major ligament that helps stabilize the knee, frequently happen at the same time as meniscus tears.^[3] This combination of injuries can make recovery more challenging and may require more comprehensive treatment approaches.

What Causes Meniscus Tears

The meniscus can tear through two main mechanisms: acute trauma or degenerative changes that happen over time.^[3] Understanding which type of tear you have is important because it influences how the injury is treated and what the recovery process might look like.

Acute meniscus tears typically happen during sports activities. These tears can occur through either contact or non-contact injuries. A common scenario involves pivoting or cutting movements where your knee twists while your foot stays planted firmly on the ground.^[2] Imagine a basketball player suddenly changing direction while dribbling, or a soccer player pivoting to pass the ball. In these moments, the forceful twisting motion can tear the meniscus tissue. Contact sports also increase the risk because getting hit or tackled can force your knee to twist unnaturally, tearing the cartilage in the process.^[2]

Any activity that causes you to forcefully twist or rotate your knee, especially when putting your full weight on it, can lead to a torn meniscus.^[1] Even activities outside of organized sports can cause these injuries. For instance, suddenly twisting when you play sport can create enough force to damage the meniscus.^[5]

As people age, they become more likely to experience degenerative meniscus tears. The cartilage in your knees naturally wears down and becomes weaker over time, making this thinner cartilage tear more easily.^[2] Aged, worn tissue is simply more prone to tears than the healthy tissue of younger people.^[3] In these cases, even minor movements that wouldn’t trouble a younger person can cause a tear. An awkward twist when getting up from a chair may be enough to cause a tear in an aging meniscus.^[3] People whose cartilage wears down due to age or arthritis can tear a meniscus from a motion as simple as stepping on an uneven surface.^[2]

Arthritis, which is a breakdown of cartilage in the joints, can also lead to meniscus tears.^[2] Sometimes, degeneration from arthritis causes a tear even without any obvious knee injury or traumatic event.^[2] This means that some people develop meniscus tears simply as part of the aging process and the gradual deterioration of their knee structures.

Who Is at Higher Risk for Meniscus Injury

Certain groups of people face a higher risk of experiencing meniscus tears based on their activities, age, and existing health conditions. Understanding these risk factors can help people take appropriate precautions or seek early evaluation if they develop knee symptoms.

Athletes and people who play sports recreationally are particularly vulnerable to meniscus injuries. Those who play sports like tennis, soccer, basketball, or football that involve sudden, twisting movements are most likely to tear a meniscus.^[2] The rapid changes in direction, sudden stops, and pivoting motions that are common in these sports place significant stress on the knee joint and the meniscus within it.

Playing contact sports also increases your risk of a meniscus tear.^[2] In these sports, the physical contact with other players can force your knee into unnatural positions. Getting hit or tackled can make you twist your knee in ways that tear the cartilage. Even children and teenagers who play sports can develop meniscus tears, making this injury a concern across all age groups of athletes.^[2]

However, it’s important to note that degenerative meniscus tears from wear and tear of your cartilage over time are common no matter your activity level.^[2] This means that even people who don’t participate in sports can develop meniscus tears. Older people are particularly affected because their cartilage has had more time to deteriorate. The injury also commonly affects those with arthritis in their knees.^[2]

People who regularly perform activities that involve repetitive kneeling or rising from a squatting position while lifting can also be at risk for traumatic tears.^[6] This means that certain occupations or regular physical activities, even outside of traditional sports, can increase the likelihood of developing a meniscus injury.

Recognizing the Symptoms of a Meniscus Tear

The symptoms of a meniscus tear can vary depending on the severity and location of the tear. Recognizing these symptoms is important for seeking appropriate medical care and preventing further damage to the knee.

Many people who tear a meniscus feel like something has popped in their knee at the time of the injury.^[2] You might feel a pop when you tear the meniscus, though this sensation doesn’t always occur.^[3] Immediately after the injury, you might be able to continue your activity. Most people can still walk on their injured knee, and many athletes are able to keep playing with a tear.^[3] At first, you might even be able to bear weight on your injured leg without too much difficulty.^[2]

However, the situation typically changes over the following days. If you’ve torn your meniscus, it might take 24 hours or more for pain and swelling to begin, especially if the tear is small.^[1] Over two to three days, the knee will gradually become stiffer and more swollen.^[3] Your knee will start to swell and become more and more painful over the span of a few days.^[2]

Common symptoms that develop include knee pain or tenderness, particularly on the inner or outer side of the knee depending on which meniscus is torn.^[5] You might develop stiffness or swelling around your knee, though the swelling may not start for a few hours or days after the injury.^[5] The pain is often especially noticeable when twisting or rotating your knee, and many people find deep knee bending particularly uncomfortable.^[1]

People with meniscus tears often experience difficulty bending, straightening, or moving the knee through its normal range of motion.^[5] You might have difficulty straightening your knee fully or being unable to fully bend or straighten your leg.^[1][2] Some people describe a catching or locking sensation when they move their knee, or a crunching or clicking feeling.^[3][5] This happens because the torn piece of meniscus can get caught between the bones of the knee joint.

Another common symptom is the feeling that your knee might give out beneath you or give way when you try to stand or move.^[2][3][5] This sensation of instability can make people hesitant to put full weight on the affected leg or to engage in normal activities. The pain is typically worse with the knee in a bent position, for example during squatting movements.^[6]

Preventing Meniscus Injuries

While not all meniscus tears can be prevented, especially those related to aging and normal wear and tear, there are steps people can take to reduce their risk of injury, particularly traumatic tears.

Maintaining strong muscles around the knee joint is one of the most important protective factors. The muscles of the thigh, particularly the quadriceps (the large muscles on the front of the thigh), help support and stabilize the knee during movement. When these muscles are strong, they can better absorb forces during activity and help prevent the knee from twisting in dangerous ways. Regular strengthening exercises for the leg muscles can provide better protection for the meniscus and other knee structures.

Using proper technique during sports and physical activities is also crucial. Learning how to pivot, cut, and change direction safely can reduce the stress placed on the knee joint. Athletes should work with coaches or trainers to ensure they are using appropriate form during their sport-specific movements. This is particularly important in sports that involve frequent twisting and turning motions.

Warming up properly before engaging in physical activity prepares the body for exercise and may help reduce injury risk. A good warm-up increases blood flow to the muscles and joints, making the tissues more flexible and responsive. Similarly, maintaining flexibility through regular stretching can help keep the knee joint mobile and potentially less prone to injury.

For people with arthritis or other conditions that weaken the cartilage in their knees, managing these underlying conditions is important. Following treatment recommendations for arthritis, maintaining a healthy weight to reduce stress on the knees, and avoiding activities that cause pain or discomfort can help protect the meniscus from degenerative tears. People who notice their knees becoming painful or unstable should seek medical evaluation rather than continuing activities that might worsen the damage.

How Meniscus Injuries Affect the Body

To understand how a meniscus injury affects the body, it’s helpful to know what the meniscus does under normal circumstances. Each of your knees has two menisci, which are C-shaped pieces of cartilage that sit inside the knee joint.^[1] Two pieces of cartilage sit inside your knee between your thighbone (femur) and shinbone (tibia).^[2] The kneecap (patella) sits in front of the joint to provide some protection.^[3]

These rubbery wedges of cartilage act like shock absorbers for your knee, providing cushioning for your bones and knee joint.^[2] The menisci help to transmit weight from one bone to another and play an important role in knee stability.^[3] The meniscus functions as a shock absorber for the knee, dissipating about a third of the force across the knee joint.^[6] It also acts as a stabilizer of the knee joint, helping to keep the bones properly aligned during movement.

There are two menisci in each knee: one on the inner side of the knee called the medial meniscus, and one on the outer side of the knee called the lateral meniscus.^[2] A medial meniscus tear affects the cartilage on the inside of your knee, while a lateral meniscus tear affects the cartilage on the outside of your knee.^[2]

The meniscus is unique tissue in the body because it only has blood vessels supplying its outermost portion.^[6] The inner portion of the meniscus receives its nutrients by diffusion alone, meaning substances slowly pass through the tissue rather than being actively delivered by blood flow. Because the blood supply to the meniscus is poor, tears of the meniscus usually do not heal on their own.^[6] This limited blood supply is one of the most important factors in determining how a meniscus tear is treated and whether it can be repaired.

When the meniscus tears, it means the shock-absorbing cartilage has ripped. The type and location of the tear determines the severity of the injury and the treatment options available. The meniscus can tear from acute trauma or as the result of degenerative changes that happen over time.^[3] Tears are noted by how they look, as well as where the tear occurs in the meniscus. Common types of meniscus tears include bucket handle, flap, and radial tears.^[3]

When a meniscus is torn, it can no longer function properly as a cushion between the bones. This disruption affects how forces are distributed across the knee joint. If the meniscus tear doesn’t heal properly, you may have continued pain and discomfort in your knee.^[2] More significantly, meniscus injury can speed up the wear and tear on your knee joint, increasing your risk for osteoarthritis, which is a degenerative joint disease.^[2] Over time, the alteration of loading mechanics across the joint accelerates the progression of osteoarthritis.^[10]

The displaced, fragmented tissue from a torn meniscus and swelling in the knee can affect proprioception (your sense of where your body parts are in space) and the thigh muscles that support knee function.^[10] This is why people often feel like their knee might give way or buckle underneath them. The normal feedback mechanisms that help you control your knee movements are disrupted by the injury and the resulting inflammation.