There are two disk shaped structures in the knee that serve as “shock absorbers”. They help to stabilize the knee and help with load transmission. The medial meniscus lies on the inside of the knee and the lateral meniscus lies on the outside of the knee. The medial meniscus is less mobile and more susceptible to injury. It is often associated with an ACL tear. The lateral meniscus is more mobile and less prone to tear.
Meniscus tears are classified as degenerative tears and traumatic tears.
Degenerative tears occur mainly in middle aged to older adults. Structural changes in the meniscus that occur over time can lead to breakdown of the meniscus and lead to small or large meniscal tears. Tears can occur from simple twisting motions, deep knee flexion and squatting but can also occur from normal activities of daily living. Symptoms of degenerative meniscal tear can include pain along the joint line, popping, catching and swelling.
Initial treatment includes rest, ice, compression, elevation and anti-inflammatories (NSAIDS). If persistent popping and catching occurs, arthroscopy is often recommended to remove the torn piece of meniscus and clean up any areas of the rest of the knee that might have become damaged. Degenerative tears are not usually repairable due to the poor vascularity of the meniscus and the type of tear. Degenerative tears can often lead to arthritis because the load bearing function of the meniscus has been altered.
Traumatic tears are usually the result of a planting and twisting motion. This can occur during sports activities, construction work, or an awkward movement of the knee joint. Symptoms of a traumatic tear are generally the same as a degenerative tear which can include pain, popping, catching, locking, swelling and loss of range of motion. The diagnosis can usually be made by taking a good history and performing a physical exam. An MRI is often obtained to confirm the diagnosis.
Treatment of traumatic tears can include conservative measures but arthroscopy is generally recommended to remove or repair the torn fragment. The determination for repair versus removal of the torn piece depends on several factors including age of the patient, location of the tear, associated injury, and the need for a quicker recovery. Physical therapy is helpful postoperatively to help reduce swelling, regain range of motion, build strength and transition back to full activity.
If you believe you have knee pain from a meniscus tear, consult with your orthopedic surgeon.