Knee Meniscal Tears

What is Knee Meniscal Tears?

The lateral and medial menisci, which are moon-shaped and made of a tough, rubbery tissue called fibrocartilage, cover about 70% of the surface of the tibial plateau, which is the top of the lower leg bone (tibia). These menisci play a key role in distributing weight and absorbing shocks in the knee joint. They are thicker around the edges of the knee joint, thus increasing the surface area of the tibial plateau. This helps the knee joint fit together better and provides extra stability.

Most of each meniscus (about 70%) is made up of a type I collagen, providing it strength and flexibility. The inner 2/3 of the menisci in adults is referred to as the “white zone,” which doesn’t have a blood supply, so it likely gets its nutrition from the synovial fluid, a lubricating fluid in the joints.

The outer 1/3 of the menisci, or the “red zone,” does have a blood supply, receiving it through branches of the medial and lateral genicular arteries, which serve the knee. This part of the menisci also contains free nerve endings that can sense pain, while sensors located in the front and back parts of the menisci, suggested to have a function in sensing movement and position.

The medial meniscus, which is on the inner side of the knee, is firmly attached to the joint capsule and the medial collateral ligament (a ligament on the inner side of the knee), making it less mobile than the lateral meniscus, which is on the outer side of the knee. The lateral meniscus is not attached to the lateral collateral ligament (a ligament on the outer side of the knee) and has looser connections with the joint capsule.

The menisci are also linked to the tibial plateau by their front and back ends, and the front ends are connected by the transverse intermeniscal ligament. On the other hand, the back end of the lateral meniscus is connected to the thigh bone via meniscofemoral ligaments and to an adjacent tendon called the popliteus tendon.

What Causes Knee Meniscal Tears?

A meniscal tear, which is a type of knee injury, often occurs due to movements that involve rotation or shearing forces on the knee joint. This happens especially when the knee is under heavy weight or is carrying a large load. This type of injury can occur during activities such as kneeling, squatting, lifting heavy objects, or during physical activities that involve quick changes of pace, shifts in direction, or jumping. A strong impact to the knee may also result in meniscal tears. In some cases, these tears can occur along with bone injuries or damage to major knee ligaments like the anterior cruciate ligament (ACL) and MCL.

Individuals who have wear-and-tear changes in their knees – mostly adults over the age of 40 – can experience meniscal tears with relatively fewer forces. This often goes hand-in-hand with osteoarthritis, a condition that causes joint damage.

Risk Factors and Frequency for Knee Meniscal Tears

Meniscal tears, or tears in the knee’s cartilage, are quite common, both among the general population and particularly in the active military population. Certain activities and roles, such as infantry duties, jobs that involve lots of squatting or kneeling, and a range of sports significantly increase the risk of these tears. People who are male or over 40 years old, or have a certain knee condition (ACL-deficiency), are also at higher risk.

Meniscal tears are commonly seen in the general population, with a rate of 61 per 100,000 people, and in active-duty military personnel, with a rate up to 8.7 per 1,000 people.
Risks are higher for those involved in infantry duties, occupations requiring frequent squatting or kneeling, and sports like soccer, rugby, football, basketball, baseball, skiing, and wrestling.
These tears are more frequent in males, and individuals over 40 years old.
Tears in the medial meniscus (one of the two types of cartilage in the knee) are more common than those in the lateral meniscus. This may be due to the medial meniscus’ connection to the MCL (a ligament in the knee), restricting movement and increasing potential for tears.
People with ACL-deficient knees (a condition where one of the major ligaments in the knee is damaged) stand a higher chance of developing these tears, especially if they don’t get reconstructive surgery within a year of their initial injury.
Children under 10 years old rarely experience meniscal tears. However, children with a discoid meniscus, which is an anatomical variant where the meniscus extends over the tibial articular surface, may get these tears at a younger age.

Signs and Symptoms of Knee Meniscal Tears

A meniscal tear can result in a range of symptoms, depending on the severity of the injury and any damage to the surrounding area. Frequently, a person may experience a “pop” sensation and immediate swelling of the knee during an intense activity or after an accident. This could be a sign of an Anterior Cruciate Ligament (ACL) tear along with a possible medial meniscal tear. Swelling that develops slowly over a 24-hour period often indicates a stand-alone meniscal tear. Some people may experience gradual symptoms where minor swelling and stiffness occur over several days even without a specific injury. Usual areas of pain include the front and inner or outer parts of the knee. Depending on the type and size of the meniscal tear, other symptoms such as a locking sensation, clicking sounds, catching, occasional inability to completely straighten the knee, or a feeling that the knee is unstable could be felt.

A physical examination for a possible meniscal tear will involve checking the knee for swelling, feeling the joint line, testing the range of motion while standing and lying down, muscle strength tests, and other specialized tests. Tenderness around the front and sides of the joint, particularly when the knee is bent at 90 degrees, can suggest a meniscal tear. The presence of pain or a range of motion limitations when bending or straightening the knee is often relied on during the diagnosis process. A limp or increased pain when squatting due to the added pressure on the meniscus might also indicate a tear. Various specialized tests like the Thessaly test, McMurray’s test, and Apley’s compression test offer various degrees of reliability in detecting meniscal tears.

Testing for Knee Meniscal Tears

If your doctor suspects a tear in your meniscus, which is a piece of cartilage that provides a cushion between your thigh bone and shin bone, the typical first step is to order X-rays. These images not only show your bones but also any possible bone diseases, loose fragments, or signs of arthritis. X-rays are taken from different angles such as the front (AP), side (lateral), angled (oblique), bent knee (sunrise), and while you’re standing (weight-bearing).

However, while X-rays are useful, the most effective way to diagnose and understand the type and degree of a meniscal tear is using Magnetic Resonance Imaging (MRI). An MRI uses a magnetic field and radio waves to create detailed images of the inside of your body.

When comparing MRI results to the findings from an arthroscopy (a type of keyhole surgery used to look inside a joint), MRIs were able to accurately detect 93% of tears in the medial meniscus (the meniscus on the inside of the knee), and 79% of tears in the lateral meniscus (the meniscus on the outside of the knee). Moreover, MRIs were able to correctly identify the absence of tears in 88% of medial meniscus cases and in 96% of lateral meniscus cases.

Treatment Options for Knee Meniscal Tears

If you have a painfully swollen knee that might indicate a torn meniscus, the first line of treatment usually involves the “RICE” method used for acute soft tissue injuries. This stands for Rest, Ice, Compression, and Elevation. Your doctor might also recommend over-the-counter pain relievers and anti-inflammatory drugs (NSAIDS) to help with pain and swelling. Additionally, wearing a brace or a knee sleeve could provide protection and compression. Engaging in gentle knee and ankle exercises that don’t cause pain may also prevent the loss of mobility and help control swelling.

If the tear is small and located on the outer part of the meniscus, or if the tear is due to degeneration, it might be advisable to rest and undertake physical therapy for 4 to 6 weeks. This approach can sometimes allow the injury to heal on its own and let you return to your normal level of activity. However, if pain, swelling, and mechanical symptoms persist beyond conservative management, it may be necessary to consider surgery.

Should you need surgery, the preferred option is often to repair the meniscus rather than remove it. This is because removal of the meniscus can lead to faster development of osteoarthritis due to diminished cushioning and increased pressure on your knee joint surfaces. Factors that increase the chances of a successful meniscus repair include tears located in the well-perfused part of the meniscus (known as the red zone), short tears (less than 2cm), vertical longitudinal tears, and recent acute tears.

After a meniscus repair, you typically have to follow specific restrictions on knee movement and weight-bearing for the first six weeks post-surgery, depending on the location and type of the tear. In some cases, when the meniscus is significantly damaged, a procedure known as a meniscal allograft transplantation may be considered. This is generally a last resort treatment option for symptomatic patients under the age of 50 who lack a functional meniscus, but who have otherwise stable knees.

Here are some conditions or injuries that may arise in the leg and lower body:

Anterior cruciate ligament injury
Contusions (bruises)
Iliotibial band syndrome (pain in the outer part of the knee)
Knee osteochondritis (inflammation of the bone and cartilage in the knee)
Lateral collateral knee ligament injury (injury to the ligament on the outer side of the knee)
Lumbosacral radiculopathy (nerve pain in the lower back and legs)
Medial collateral ligament injury (injury to the ligament on the inner side of the knee)
Medial synovial plica irritation (irritation of the inner knee fold)
Patellofemoral joint syndromes (issues with the joint in the knee cap)
Posterior cruciate ligament injury (injury to the ligament in the back of the knee)

Frequently asked questions

Knee meniscal tears are tears in the moon-shaped fibrocartilage structures called the lateral and medial menisci, which play a key role in weight distribution and shock absorption in the knee joint. These tears can occur due to injury or degeneration and can cause pain, swelling, and limited knee movement. Treatment options for knee meniscal tears may include rest, physical therapy, or in some cases, surgery.

Meniscal tears are commonly seen in the general population, with a rate of 61 per 100,000 people, and in active-duty military personnel, with a rate up to 8.7 per 1,000 people.

Signs and symptoms of Knee Meniscal Tears include: - "Pop" sensation and immediate swelling of the knee during intense activity or after an accident - Swelling that develops slowly over a 24-hour period - Gradual symptoms with minor swelling and stiffness occurring over several days, even without a specific injury - Pain in the front and inner or outer parts of the knee - Locking sensation in the knee - Clicking sounds in the knee - Catching sensation in the knee - Occasional inability to completely straighten the knee - Feeling that the knee is unstable During a physical examination for a possible meniscal tear, the following signs may be observed: - Swelling of the knee - Tenderness around the front and sides of the joint, particularly when the knee is bent at 90 degrees - Pain or range of motion limitations when bending or straightening the knee - Limp or increased pain when squatting due to added pressure on the meniscus Specialized tests that can be used to detect meniscal tears include: - Thessaly test - McMurray's test - Apley's compression test It is important to note that the severity of symptoms and the specific signs may vary depending on the type and size of the meniscal tear, as well as any damage to the surrounding area.

A meniscal tear in the knee can occur due to movements that involve rotation or shearing forces on the knee joint, especially when the knee is under heavy weight or carrying a large load. It can also happen during activities such as kneeling, squatting, lifting heavy objects, or physical activities that involve quick changes of pace, shifts in direction, or jumping. A strong impact to the knee can also result in meniscal tears. Additionally, individuals who have wear-and-tear changes in their knees, mostly adults over the age of 40, can experience meniscal tears with relatively fewer forces, often in conjunction with osteoarthritis.

Anterior cruciate ligament injury, Contusions (bruises), Iliotibial band syndrome (pain in the outer part of the knee), Knee osteochondritis (inflammation of the bone and cartilage in the knee), Lateral collateral knee ligament injury (injury to the ligament on the outer side of the knee), Lumbosacral radiculopathy (nerve pain in the lower back and legs), Medial collateral ligament injury (injury to the ligament on the inner side of the knee), Medial synovial plica irritation (irritation of the inner knee fold), Patellofemoral joint syndromes (issues with the joint in the knee cap), Posterior cruciate ligament injury (injury to the ligament in the back of the knee)

The types of tests needed for knee meniscal tears include: 1. X-rays: These images are taken from different angles to show the bones and any possible bone diseases, loose fragments, or signs of arthritis. 2. Magnetic Resonance Imaging (MRI): This is the most effective way to diagnose and understand the type and degree of a meniscal tear. An MRI uses a magnetic field and radio waves to create detailed images of the inside of the body. 3. Arthroscopy: This is a type of keyhole surgery used to look inside a joint and can be used to compare the findings with the results of an MRI. It is important to note that the MRI has been found to be more accurate in detecting meniscal tears compared to arthroscopy.

The treatment for knee meniscal tears typically involves the "RICE" method, which stands for Rest, Ice, Compression, and Elevation. Over-the-counter pain relievers and anti-inflammatory drugs may also be recommended. Wearing a brace or knee sleeve can provide protection and compression. Gentle knee and ankle exercises that do not cause pain may help prevent loss of mobility and control swelling. In some cases, rest and physical therapy may be sufficient for small tears or tears located on the outer part of the meniscus. Surgery may be necessary if conservative management does not alleviate symptoms, with meniscus repair being the preferred option over removal. After surgery, specific restrictions on knee movement and weight-bearing may be required for the first six weeks. Meniscal allograft transplantation may be considered as a last resort treatment option for patients who lack a functional meniscus but have otherwise stable knees.

When treating Knee Meniscal Tears, there are potential side effects to consider. These may include: - Pain and swelling - Loss of mobility - Mechanical symptoms - Development of osteoarthritis (if the meniscus is removed) - Diminished cushioning and increased pressure on the knee joint surfaces (if the meniscus is removed) - Potential need for surgery if conservative management does not alleviate symptoms

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