Meniscus tear

Definitions & Key takeaways

Meniscus tear is when one or both of the menisci of the knee joint are torn. Acute tears usually occur in athletes during contact sports, when the menisci are violently compressed. Chronic tears can also occur, often in older people due to wear and tear changes of menisci. Symptoms include pain, swelling, and stiffness, and the diagnosis is mainly based on clinical symptoms, physical exam with an MRI for confirmation. Treatment can be conservative, or by open or arthroscopic surgery.

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Introduction0:00–0:23

. The menisci are crescent-shaped fibrocartilage cushions found in the knee joint.
Normally there's a medial and lateral menisci between the femur and the tibia, so a meniscus tear, more commonly known as torn knee cartilage, is when one of the menisci of the knee is torn.
This can occur acutely due to trauma or twisting during sports, which is usually seen in younger people, whereas in older individuals, meniscal tears are often degenerative, also known as a chronic tear.

Physiology0:23–1:47

The knee is a complex joint. Actually, it's a combination of two joints.
These are the patello femoral joint, formed by the femur and patella, and the tibiofemoral joint, which is formed by the bony prominences, also called the condyles of the femur and the proximal surface of the tibia.
Between the femoral condyles and tibial surface are the medial menisci and lateral menisci. The menisci act to absorb compressive force which can reach up to 3 times the body weight while walking.
In addition, the menisci have a cup-shaped surface which provides a deeper place for the condyles to fit in, improving joint stability.
Next, the knee joint is supported by a number of ligaments. So within the joint space there's the anterior cruciate ligament or ACL, which runs from the anterior middle edge of the tibia to the lateral condyle of the femur.
And the posterior cruciate ligament or PCL that runs from the middle posterior edge of the tibia to the medial condyle of the femur.
Now outside the joint space, the lateral collateral ligament or LCL runs from the femur to the fibula. On the medial side of the knee, another collateral ligament runs from the femur to the tibia.

Pathology1:47–3:13

This one is called the medial collateral ligament or MCL. The MCL is firmly attached to the medial meniscus, which makes it less mobile compared to the lateral meniscus.
Acute meniscal tears are usually seen in young athletes and typically occur when a weight bearing knee is bent and at the same time excessively twisted, like when you're playing basketball and then you suddenly change direction trying to cross over another player.
Acute meniscus tears can also occur as part of the unhappy triad injury where there are simultaneous tears of the ACL, MCL, and a meniscus.
This can occur when there is a sudden lateral blow to the knee while the foot is planted on the ground, like when a football player is hit on the side of the knee by another player.
Although a lateral meniscus tear is more common when the ACL is also acutely injured, medial meniscus tears are more common overall.
This is due in part to its firm attachment to the MCL and the joint capsule, which reduces its mobility. In contrast to an acute tear, there are also chronic or degenerative meniscal tears which usually occur in people who are of older age.
This is because the wear and tear of the menisci make them more susceptible to tears with minimal force, so there may not even be any noticeable trauma.
In this case, someone might tear their meniscus from simply getting up from a chair. All right, let's talk about symptoms.
In an acute tear, there can be intense pain in the joint at the time of the trauma. Over the next 24 hours, joint pain and swelling increase.

Symptoms3:13–3:47

In addition, a piece of the torn meniscus can get stuck between the femur and the tibia, restricting joint movement called joint locking.
Sometimes a meniscus fragment can cause a clicking sound or a popping sensation when trying to extend the knee. In contrast, in chronic tears, pain can be minimal or absent.
However, mechanical symptoms like joint locking or popping sensation can still be present. The diagnosis of a meniscus tear starts with the history and clinical symptoms in addition to special testing at the knee.

Diagnosis3:47–4:58

One of the most important tests used is the McMurray test, where the patient lies supine, the knee is flexed. Internally rotated to stress the lateral meniscus, and then the knee is extended.
If the person feels pain or if you feel a click or a pop while extending the knee, there's likely a lateral meniscus tear.
To diagnose a medial meniscus tear, the knee is again flexed, but this time it is externally rotated to stress the medial meniscus, followed by extension.
An X-ray can't show a meniscus tear, but it is still an important part of the workup of a suspected meniscus tear since it can identify fractures associated with an acute injury.
It can also help identify degenerative changes in the joint like those of osteoarthritis, which is commonly found in cases of chronic meniscal tears.
Examples of osteoarthritic changes are joint space narrowing, osteophyte formation, which are small bony projections, and subchondral sclerosis, which means hardening of the bones that underlies the joint cartilage.

Treatment4:58–5:20

However, the diagnosis of a meniscus tear can be confirmed using an MRI. MRI will not only show the tear but also the size and location, which can be helpful in deciding management options.

Review5:20–6:30

The treatment of meniscus tears begins with ice to reduce inflammation, rest, and non-opioid pain medications such as acetaminophen or non-steroidal anti-inflammatory drugs or NSAIDs if needed.
Also, physical therapy can help improve range of motion and strengthen the muscles around the knee, which helps decrease the load on the menisci.
In some cases, open or arthroscopic surgery may be needed to repair the torn meniscus. All right, as a quick recap, meniscus tear is when one or both of the menisci of the knee joint are torn.
Acute tears usually occur in athletes during sports due to either a twisting motion or a lateral blow to the knee while the foot is planted on the ground.
On the other hand, chronic tears tend to occur in people who are of older age and are due to wear and tear changes of the menisci.
The diagnosis is mainly based on history and clinical symptoms like knee pain and swelling with a positive McMurray test on examination and can be confirmed by MRI.
Treatment can be conservative or by open or arthroscopic