One of the great things about my job as a sports medicine orthopaedic surgeon is that I get to meet many new people every week. Patients in my practice range in age from approximately 12-90, and they range in activity level from couch potato to elite athlete. There is one particular knee injury that I see commonly across the whole spectrum of patient types, and that is the meniscus tear. Are all of these meniscus tears treated the same? Absolutely not, and I will try to describe my decision-making process in dealing with these injuries. For a more complete discussion, see the meniscus tears section of my website.
What exactly is the meniscus?
The meniscus is a rubbery, fibrocartilage structure inside the knee that provides cushioning and support for the knee during impact and weight bearing activities. I often describe it to patients as the shock absorber of the knee. There are two menisci in each knee, one on the medial side (inside) and one on the lateral side (outside). The medial meniscus is slightly larger than the lateral meniscus, and is more commonly torn than the lateral meniscus.
What causes a tear in the meniscus?
In young people, meniscus tears are usually traumatic and a result of a twisting injury of the knee. They can be seen in isolation or in conjunction with a ligamentous injury of the knee – particularly in association with an ACL tear. In older patients, a meniscus tear may occur without any significant trauma. These tears are termed degenerative tears, and occur because the substance of the meniscus may degrade and weaken after years of wear and can tear more easily.
What are the symptoms of a meniscus tear?
Meniscus tears generally cause pain along the joint line and (at least initially) swelling in the knee. Depending on the size and type of the tear, they can also cause mechanical symptoms such as clicking, catching, or even locking of the knee. The symptoms generally will improve slowly over time, but may recur or worsen with activity. Some tears will cause chronic pain, but some may resolve almost completely.
Can a meniscus tear be fixed?
The most common question that I am asked by patients with a meniscus tear is “Can you stitch it back up?” That is a very logical question, and the answer to that question is “sometimes”. In young patients, for example a high-school athlete with a meniscus injury, the best treatment is an attempted meniscus repair. This decision is based on many factors, but unless the meniscus is torn beyond repair then I will almost always try to fix it in a young person. Why? The meniscus with its role as a shock absorber helps to protect the articular cartilage of the knee joint over the life of the knee. If this protection is lost at a young age, then the knee may become arthritic at an early age, which is an orthopaedic problem without a good solution. So, even if the meniscus repair fails in a young person and it requires a further surgery, I feel like it is worth the attempt.
Why wouldn’t you always fix a meniscus tear?
The reason that meniscus tears aren’t always fixed is that the meniscus has no blood supply in adulthood and as a result has very limited healing potential. This is especially true in degenerative type tears, where the meniscal tissue is already compromised and the healing potential is almost zero. Many times, trimming out the torn portion of the meniscus is a better option than repair.
If you trim out the meniscus tear, does it grow back?
No, the meniscus has limited healing potential and essentially no regenerative potential, so it won’t grow back. If it is trimmed out, there is some loss of the shock absorption and protective function. This function was basically lost when the meniscus was torn with most types of tears, so trimming out the tear does not add further damage.
Do all meniscus tears need surgery?
The short answer is no. Let’s start with the extreme cases. In a 14 year old with a large meniscus tear, I would recommend surgical in nearly all cases. In an 84 year old with severe knee arthritis, I would never recommend surgery for a meniscus tear. What about everyone in between these extremes? Those decisions are based on the age and activity level of the patient, and the size and type of the meniscus tear. Some small tears without any mechanical symptoms will respond well to conservative treatment (ice, anti-inflammatories, physical therapy, cortisone injection, etc.). There is certainly no emergency in treating a meniscus tear, so attempting conservative treatment for a few weeks before jumping to surgery is a good strategy that may help you avoid surgery altogether.
Adult patients that have meniscal tears and also have mechanical symptoms such as locking or catching of the knee will usually have better results with surgery, even if there is some arthritis present. Mechanical symptoms often correlate with a flap-type tear of the meniscus, which can displace inside the knee and cause more discomfort than a stable tear in the meniscus.
The decision to proceed with arthroscopic surgery for a meniscus tear depends on many factors and is individual to each patient. I spend time with each patient in the office discussing all these factors and we come to a decision together.