• Where is the meniscus located and what does it do?

    Inside the knee there are two cartilage discs that contribute to the cushioning of the knee.  Each cartilage disc is called a meniscus.  There is one meniscus on the inner or medial aspect of the knee (medial meniscus) and one on the outer or lateral aspect (lateral meniscus).  Along with the articular cartilage that covers the ends of the femur (thigh bone) and tibia (shin bone) a smooth gliding surface is created.  The meniscus cartilages help to protect the articular cartilage that caps the ends of the bones that form the knee joint.  When the articular cartilage that covers the bone wears we call this “arthritis.”  I tell patients that their meniscus is not like their appendix.  If a patient gets appendicitis and has their appendix removed they have lost nothing of value.  The meniscus on the other hand serves a valuable purpose protecting the knee from arthritis. It is because of this function and value that the meniscus has that we attempt to preserve it as much as possible.

  • How does a meniscus get injured or torn?

    Sometimes patients will injure or tear their meniscus cartilages.   I explain to patients that their meniscus cartilages are more or less hooked together to form a ring within the knee.  When we step down these discs expand or stretch out to help absorb the stress or shock.  Functionally the medial and lateral meniscus work together like a hoop around a barrel.  As water is placed into the barrel the hoop works to distribute the stress and hold the barrel together.  This analogy is very important as I also explain to patients as well as when teaching to others about the topic that not all meniscus tears are created equal.  Some simply tear though a portion of the meniscus where others break or sever the meniscus in half.  Those that injure just a portion of the meniscus are functionally like thinning out the barrel hoop.  The hoop is somewhat weaker and thinner but the circle of the hoop is intact and the function remains the same.  In those tears where the meniscus is completely torn through these are like cutting or breaking the hoop.  Once the hoop is broken it does not matter if a small sliver is cut thru the hoop or a large segment is removed.  In either case the hoop no longer functions to hold the barrel together and all function is lost.

    Meniscus tears can be caused by injuries—slips, falls, twisting, etc. and sometimes they develop without recognized or identifiable cause.  Tears that occur without a specific injury are much more likely to occur in patients over the age of 40 and are likely “degenerative” in nature.  By describing these tears as “degenerative” it means that the tears have occurred in a meniscus that is weakened by age.  In this case a weakened meniscus tears even when subjected to what we would consider a normal stress such as walking or climbing up stairs.   These meniscus tears typically occur in knees that have some degree of wear to the articular cartilage of the knee.  Stated another way patients with these tears over that occur without injury almost always have some associated arthritis.  Associated arthritis definitely becomes more common the older the patient is at the time of diagnosis.

  • What are the symptoms of a torn meniscus?

    When the meniscus is torn it can cause symptoms.  Symptoms vary from patient to patient but frequent complaints include pain—usually localized to the side of the knee where the tear has occurred, swelling, and sometimes mechanical symptoms such as catching, popping, grinding or locking.  Frequently these symptoms are brought on or worsened by activities that put stress on the meniscus such as pivoting, twisting, or squatting.  If a torn meniscus happens to be detected on MRI but a patient is not having any of these symptoms there is no evidence that the tear requires additional treatment or that it is causing additional damage.  It is fairly common that patients will have MRIs ordered because of pain and a meniscus tear is found.  By the time the patient follows up with the doctor the pain has sometimes decreased significantly or gone away all together.  Patients will ask if the tear has healed.  The tear in all likelihood has not gone away or healed but in the absence of the symptoms discussed above surgery to trim or treat the meniscus tear is likely of no benefit.

  • Are there any non-operative options?

    No non-operative treatment actually “fixes” the meniscus tear but as discussed above what really is important with meniscus tears are the symptoms.  Occasionally a period of activity modification, use of an anti-inflammatory medication, or a steroid injection will decrease or resolve the patient’s symptoms.  If that should be the case no additional treatment is likely necessary.  For those patients with persistent symptoms in spite of conservative or non-operative treatment surgery is an option.  The surgery is accomplished by arthroscopy where the meniscus and inside of the knee is examined through to small poke holes using an arthroscope.   Using this small scope and tiny poke holes options are between trimming the meniscus tear smooth or repairing it with stitches.  Probably only 10% or less of all meniscus tears can be repaired rather than just trimmed smooth.  These cartilage discs heal very poorly because they have very little blood supply so there are only certain tears—those near to the blood supply—that are really capable of being stitched.  These tears almost always occur in younger patients with athletic injuries or in those with associated injuries such as ACL tears.

  • What are the surgical options?

    Most meniscus tears that remain painful are therefore treated by trimming or so called “partial menisectomy.” Surgery is done on an outpatient basis and typically takes less than one hour. There are no post-operative restrictions and patients can begin to bend their knee and put weight on their leg the day of surgery. Rates of recovery vary from patient to patient but most never need cane or crutches and many feel no need for physical therapy beyond what they can accomplish on their own at my direction.  Most patients can resume unrestricted or normal activities within 2 to 6 weeks after surgery.

    Every surgery involves some risks and standard potential risks include blood clots in the leg and infection. Both of these are uncommon.  The most significant issue is frequently the risk of persistent or progressive arthritic pain. As discussed above, most cartilage tears are “degenerative” in nature so patients almost always have some associated arthritis even if they were previously unaware of that diagnosis. Because the meniscus has an important role in cushioning the knee damage to the meniscus can unmask arthritis that previously was not causing symptoms. Often x-rays and MRI done before surgery will allow us to assess and discuss the likelihood of this risk before any surgery is undertaken.  Some meniscus tears such as those that tear all the way through or break the “hoop” are at a much greater risk for this problem.  Be assured that there are other treatments available should this become a problem.

  • Where can I learn more?

    I hope that you have found this discussion and information helpful whether you are just looking for information about the diagnosis or planning additional treatment.  Below are several additional resources that I hope you will find helpful.  I look forward to helping you with your knee problem.

    Meniscus Tears

    Knee Arthroscopy

    Meniscus Rehab

    DVT Prophylaxis

  • Post-Operative Instructions


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