What is a meniscus?
The meniscus is a c-shaped piece of cartilage that sits between the femur (thigh bone) and the tibia (shin bone) at the knee joint. It functions primarily as a shock absorber, helping to protect the cartilage of the knee by dissipating the force that happens every time you take a step. It also functions secondarily to stabilize the knee. Each knee has two menisci, one on the medial or inner side of the knee and one on the lateral or outer side of the knee.
Diagnosing a Torn Meniscus
The most common symptom of a meniscus tear is pain. Pain is typically worse with the knee in a bent position, for example during squatting. Some people also experience swelling and stiffness which could manifest as difficulty bending or straightening the knee. Other people also experience a sense of catching or locking within the knee, as well as the knee giving out or giving way. A doctor doing an exam can move your leg in certain ways to suggest a meniscus tear. While an x-ray is a standard part of an initial evaluation, we cannot see the meniscus on x-ray; seeing the meniscus requires an MRI. However, an x-ray gives us a lot of other information about other potential causes for knee pain and swelling.
There are many different types of meniscus tear. Some types of tear leave the meniscus still functional while others render the meniscus nonfunctional. The type of tear also affects the type of treatment.
Treating a Meniscus Tear
Choosing a Treatment
Beside the type of tear, other factors are considered when deciding on a treatment. Age is a consideration, as is the reason: did the tear happen due to an acute injury or from degenerative changes such as arthritis?
One of the most important aspects to understand about the meniscus is its limited blood supply. The blood vessels only travel so far into the meniscus from the outer edge. Blood supply is required for a meniscus to heal, so tears of the inner edge of the meniscus are often not repairable because they don’t have the blood supply that’s necessary to heal.
Other issues may be occurring in a knee at the same time as a meniscus tear. Injuries that cause ligament tears such as a tear of the ACL often have meniscus tears at the same time. Arthritis is the most common coexisting problem with a meniscus tear. With arthritis, the cartilage on the ends of the bones is degenerated. If a knee has arthritis, it’s very likely that the loss of cartilage is causing more problems than the meniscus tear.
Types of Treatment
When we talk about treatment options the first line of for most meniscus tears is non-surgical just as with any other injury: rest, ice, compression and elevation work to decrease swelling and inflammation, thereby decreasing pain.
Anti-inflammatory medications, both non-steroidal and steroids, can be very effective in decreasing inflammation and pain. Other pain relievers, such as Tylenol or topical treatments like lidocaine patches or capsaicin cream, may also be effective.
Rehabilitation exercises to strengthen the muscles around the joint can be very helpful. Working with a physical therapist can incorporate not only a specifically designed rehab program but also other ideas and techniques which may be helpful.
There are multiple types of injections, the most common of which is a corticosteroid, also known as steroid or cortisone injections. Those injections decrease inflammation and can be very helpful in controlling pain. There are other injections that are used less frequently but can also be effective such as viscosupplementation or PRP (platelet rich plasma) injections.
Meniscus surgery often falls into two categories: repair or removal. All of the meniscus surgery that I perform is done arthroscopically which is a minimally invasive technique using a camera and specialized tools to work within the joint through small incisions.
Each patient’s treatment plan is individualized based on many factors.
Frequently asked questions
What are the activities you should not do when you have a meniscus tear?
Use your pain as a guide to tell you what you can and can’t do. That tends to be deep bending or squatting position especially with loading. If you bend your knee when you’re not standing on it, it might be okay, but going into a squatting position will be more irritating. In general, lower impact activities tend to be less irritating than higher impact activities like running or jumping. The activities that don’t cause pain are probably safe to continue.
How long is recovery after a meniscus tear?
It varies. For meniscus cleanup surgeries, you go home the day of surgery and you can start putting weight on your leg as soon as you’re comfortable doing so. For a meniscus repair, it’s generally two to four weeks of not putting any weight on your leg and then another two or so weeks using crutches to start putting some weight on your leg. So it can be wide variation depending on the procedure, anywhere from starting to walk the day after to being on crutches for about six weeks after surgery.
What’s the connection between arthritis and meniscus tears?
The most common situation where I see meniscus tears is in people who have some arthritis as well. The question is identifying which patients who have a meniscus tear and arthritis are going to get better from just cleaning up the meniscus, because the arthroscopic surgeries that I do can’t address arthritis. They can’t put cartilage back where it’s worn away. How much pain is coming from the arthritis? How much pain is coming from the meniscus tear? If you have severe arthritis, cleaning up the meniscus probably won’t help you. If you have mild arthritis, cleaning up the meniscus could be very helpful. We take into account what the x-rays and MRI look like to get a sense of how much pain is coming from arthritis, which helps to decide how much improvement you might see after a meniscus surgery.
Do you have tips on keeping a knee healthy after a meniscus repair?
The first tip is to follow restrictions and work with a physical therapist after any surgery. Once the meniscus tear heals the best thing that you can do is keep the muscles around the knee strong, which helps to stabilize the joint. Finally, maintaining a healthy lifestyle with moderate vigorous activity several times per week and maintaining a healthy weight also keep the knee healthy.
What is the cause of a popping sensation in the knee after a meniscus tear?
Often, the meniscus tear will create a little flap of tissue. Depending on the position of the knee, that little flap of tissue can move around. It’s generally not anything dangerous that you need to have taken care of, but it can be very uncomfortable. Patients with this type of catching or locking in the knee tend to find the greatest improvement after meniscus tear surgery. While it’s nothing dangerous, it can be symptomatic and is something that arthroscopic surgery typically helps.
Do you recommend cold or heat to reduce pain?
In general, especially after an injury, cold is probably going to feel better. When you have a meniscus tear and arthritis, you tend you have swelling and pain from inflammation. Cold helps decrease swelling and inflammation. If heat feels better on your knee, however, there’s no downside to using it.
If you have a small meniscus tear, do you need to get treatment immediately?
If you have an injury and think you may have a meniscus tear, the best thing to do is to seek treatment to identify and characterize the tear. There are some tears that essentially render the meniscus useless or nonfunctional. If the meniscus is torn in one of those ways, repairing it early will help to preserve the function of the knee long term because we’re giving back that shock absorber and stability to the knee. In other cases, when the meniscus is torn in a way where it does not need to be repaired or cannot be repaired, it’s not hurting to manage it non-operatively as long as possible. However, you need a diagnosis to know which type of tear you have.
Can PRP regrow the meniscus?
PRP is used for its anti-inflammatory effects. There’s nothing that exists right now that can help regrow the meniscus.
Who is likely to have a meniscus tear?
Anybody can get a meniscus tear. For a young person it’s very likely to be associated with a specific injury, such as during sports. For people in their 40s, 50s or 60s, degenerative meniscus tears can happen without any kind of injury. If you have arthritis, you are at higher risk of having a meniscus tear as well, but if the arthritis is severe enough the arthritis is more of an issue in causing pain than the meniscus tear is.
What exercises do you recommend people do at home to help with meniscus tears?
In general, anything that strengthens the muscles around the knee and works on preserving knee range motion is going to be very helpful. The American Academy of Orthopaedic Surgeons (AAOS) has a good at home program available online. You can also work with a physical therapist who can design a program specifically for you.