There are two menisci in the knee joint; medial (inside part of the knee) and lateral (outside part of the knee). They are “C” shaped cartilages that sit between the tibia (shinbone) and the femur (thighbone). The purpose of the meniscus is to improve the fit between the femur and the tibia, and it serves to help distribute weight evenly across the joint. The meniscus can tear from either an injury such as an ACL injury, or from the early development of osteoarthritis. About 80% of the meniscus has no blood supply with the blood supply being only at its outer attachments. Therefore, when the meniscus tears it cannot heal on its own.
Not all meniscus tears require a surgery for pain relief. In fact, dependent on type of tear, surgery on certain types of tears with an arthroscopy can only make knee pain worse. There are over 850,000 knee arthroscopies performed every year in the United States and many of these procedures are not necessary. Prior to the COVID-19 pandemic, we were learning that many people were getting better with proper non-operative treatment. Then, when we were forced to stop all elective procedures from mid-March to June 2020 because of COVID, we found that the majority of patients we saw in February and early March with a meniscus tear got better with the treatment we provided them for home management until surgery was available. Therefore, it is important to understand the cause, location and type of tear you are dealing with and know that surgery is going to make the knee pain go away. It is also important to know that a surgery for this problem does not give the patient a normal knee, but it removes the thing that is causing pain.
Knee Exam and Patient History are Key
Many orthopedic surgeons do not know how to properly examine the knee, and strictly rely on an MRI scan for the diagnosis. In patients who are over 40 years of age or have had a previous knee surgery, an MRI scan is not going to be normal, and will often read as a meniscus tear. The purpose of the MRI scan should always be to confirm and correlate the findings on the MRI scan with the physician’s physical exam and the patient’s complaints. Many physicians also are not aware that non-operative treatment is affective with meniscus tears, and orthopedic surgeons are surgeons and will typically only know how to treat the problem with a surgery. There are many times an MRI scan is ordered to look at another problem, and the report will indicate that there is a tear of one of the menisci. However, not all meniscus tears are symptomatic. Again, individuals over 40 years of age are most likely to have medial meniscus tears present on an MRI scan but have no symptoms of a tear. These tears are degenerative in nature and occur due to age and wear and tear on the joint. However, if a surgeon sees this finding on a report, more often than not, the surgeon will recommend an arthroscopy to take out the torn piece that really is not bothering the individual.
So, how do you know if you have a symptomatic meniscus tear? The most common tears are in the medial meniscus. The most common symptoms of a medial meniscus tear is pain on the inner/back side of the knee joint line and this will be tender to touch over the meniscus. There will be swelling in the joint and decreased flexion, or bending of the knee. There is typically increased pain with squatting all the way, or pain with rolling in bed, catching the toe while walking, or pushing/kicking something hard with the inside of the toes. You may or may not have locking, catching, or clicking that is painful or uncomfortable. Lateral meniscus tears are not as common but they will be symptomatic if there is tenderness on the outside and back portion of knee joint line and will also be tender to the touch. You can also have limited flexion; locking, catching or clicking that is painful or uncomfortable.
We always get x-rays prior to doing an MRI scan as the x-rays are less expensive, and if there is any evidence of arthritic changes in the joint, an MRI scan is most likely going to show that the medial meniscus is torn from its posterior (back) attachment and the meniscus is extruded from the joint to some degree. These types of tears should not be treated surgically. Some orthopedic surgeons will recommend an arthroscopy to repair these tears; keep a patient on crutches and be non-weight bearing or partial weight bearing for several weeks. However, once the patient starts to get back to their normal activities of full weight bearing, work and any recreational activity the pain returns and function decreases because the meniscus tears again. The cause of the tear is a result of the joint space between the femur and the tibia narrowing. As the joint becomes narrower, the pressure on the back portion of the meniscus cannot handle the pressure therefore it has no choice but to tear. Often times when this happens, you will hear and feel a painful pop in the joint and increased difficulty with putting weight on the leg. This is the early phase of arthritis. The best analogy to understand this process is thinking about a can in a vice. When the vice starts to put increase pressure on the can, then the can bursts. Until you remove the pressure of the vice, the can will continue to go through changes and expand outside of the vice. The meniscus is like the can, and pressure from the femur and tibia is the vice. Unfortunately, we cannot change the joint space narrowing, but we can address the symptoms to allow the knee to calm down and become more functional and less painful.
There are many options to help manage the knee pain that is secondary to a meniscus tear. If you have been told you need a surgery and no other options were provided, I would encourage you to get a second opinion before consenting to a surgery that may be unnecessary, or may make the knee pain worse.