Meniscus Tears

Inside each knee are two small pieces of cartilage called the menisci. There is a medial meniscus on the inside of the knee and a lateral meniscus on the outside. These crescent-shaped structures act as shock absorbers between the thigh bone (femur) and shin bone (tibia). They help distribute weight evenly across the joint, improve stability, and reduce friction during movement. Without a healthy meniscus, the knee experiences more stress with every step. Over time, this can lead to ongoing pain, instability, and even early arthritis.

A meniscus tear occurs when the cartilage is damaged or ripped. This can happen suddenly during a twisting injury or gradually over time as the cartilage weakens with age. Some tears are small and stable, while others are larger and may interfere with normal knee motion.

Meniscus tears vary in severity. Some cause mild discomfort that improves with rest. Others create mechanical symptoms, such as catching or locking of the knee, which require prompt medical evaluation.

Meniscus tears are classified based on their shape, location, and pattern. The most common types include:

• Radial tears. These extend from the inner edge of the meniscus outward. They are common and can disrupt how the meniscus absorbs shock.
• Horizontal tears. These split the meniscus into upper and lower sections and are often associated with age-related degeneration.
• Vertical or longitudinal tears. These run along the length of the meniscus and may progress into a “bucket handle” tear, where a portion flips into the joint and causes locking.
• Flap tears. These create an unstable fragment that can catch inside the knee.
• Complex tears. These involve multiple tear patterns and are often seen in older adults.

The location of the tear also matters. The outer third of the meniscus has a better blood supply, which improves healing potential. Tears in the inner portion have limited blood flow and are less likely to heal on their own.

Symptoms depend on the size and type of tear. Some people feel immediate pain after an injury, while others notice swelling and stiffness developing over the next day or two.

Common symptoms of traumatic tears include:

• Knee pain, especially along the joint line.
• Swelling that develops within hours or days.
• Stiffness and limited range of motion.
• A catching, clicking, or popping sensation.
• A feeling that the knee may give out.
• In more severe cases, the knee may lock and be difficult to fully straighten.

Degenerative tears may cause more subtle symptoms, such as aching pain during activity or discomfort when squatting or climbing stairs.

It is important not to ignore persistent knee pain. Continued activity on a torn meniscus can worsen the injury and increase stress on the joint surfaces.

Meniscus tears occur for two main reasons: acute injury or degeneration.

Acute tears

Acute tears often happen during sports that involve twisting, pivoting, or sudden stops. Activities such as soccer, basketball, football, and skiing commonly place stress on the knee while it is bent and bearing weight. A quick change in direction or awkward landing can cause the meniscus to tear.
However, not all meniscus tears happen in athletes. A simple movement such as kneeling, squatting, or turning quickly while standing up can cause a tear, especially if the cartilage has weakened over time.

Degenerative tears

Degenerative tears are more common in adults over 40. As people age, the meniscus becomes less flexible and more prone to fraying. In these cases, the tear may develop gradually without a clear injury. Degenerative tears are often associated with early arthritis changes in the knee.
Risk factors include prior knee injuries, ligament damage such as an ACL tear, obesity, and repetitive stress from work or physical activity.

At OrthoIllinois Knee Center, diagnosing a meniscus tear begins with a detailed medical history and physical examination. The provider will ask about how the injury occurred, when symptoms started, and what movements cause pain.

During the exam, specific tests are performed to assess joint line tenderness, swelling, range of motion, and mechanical symptoms. The knee will be gently bent and rotated to reproduce discomfort associated with meniscus damage.

Imaging studies are often used to confirm the diagnosis. X-rays do not show the meniscus itself, but they help rule out fractures or advanced arthritis. The most useful imaging test is magnetic resonance imaging (MRI). An MRI provides detailed images of soft tissues, including cartilage, ligaments, and surrounding structures. This allows the provider to identify the type, size, and location of the tear.

In some cases, symptoms and physical exam findings are clear enough to guide treatment without immediate advanced imaging. Each evaluation is individualized based on the patient’s age, activity level, and overall knee health.

Meniscus tears can affect anyone, from student athletes to active adults and older individuals experiencing degenerative changes. Early evaluation is important to prevent further joint damage and long-term complications.