What is a meniscus tear?
The knee is a hinged joint made up of a femur which is your thigh bone and the tibia which is your shin bone. The bones are covered with a smooth surface called articular cartilage. When the surface cartilage wears out it is called arthritis. The meniscus is a C shaped piece of cartilage that acts as a “shock absorber” in the knee that protects the articular cartilage on the surfaces of these bones. There are 2 of them in each knee. There is one on the inside called the medial meniscus and one on the outside called the lateral meniscus. In addition to protecting the joint surfaces, the meniscus also provides stability within the knee.
Sometimes the meniscus can be damaged, and this is called a meniscus tear. It can be thought of as a “hang nail” within the knee. There are 2 types of meniscus tears. A degenerative tear occurs when the articular surface starts to breakdown. The smooth surfaces on the ends of the bones start to turn into sandpaper as they become arthritic. This wear and tear can then chew up the meniscus which acts as the shock absorber between the bones. The meniscus itself can also breakdown with age and tear.
Other meniscus tears are classified as traumatic. These can occur during sports such as basketball, football or lacrosse. However, they can also occur with normal daily activity through a twisting injury or direct trauma to the knee.
How common are meniscus tears?
Meniscus tears are very common, and meniscal surgery is one of the most common procedures performed in orthopedics. Degenerative tears are a common finding as the articular cartilage breaks down and can damage the adjacent meniscus. Overall, they are more common in men than women. Traumatic tears usually occur between 20 and 30 years of age. Degenerative tears usually occur over the age of 40.
How do we treat meniscus tears?
Most of the time degenerative meniscus tear are treated with conservative measures including physical therapy, anti-inflammatories and/or cortisone injections. However, sometimes degenerative tears and often traumatic tears can become more symptomatic, causing mechanical symptoms (catching, locking, giving out, or blocking motion). When this happens, we usually need to perform a minimally invasive outpatient procedure called arthroscopy when we remove the tear or “hang nail.” Depending on the type of tear and quality of the tissue, we can sometimes repair the meniscus with stitches.
Greis PE, Bardana DD, Holmstrom MC, Burks RT. Meniscal injury: I. Basic science and evaluation. J Am Acad Orthop Surg. 2002;10:168-176.