What is a meniscus?
The meniscus is an important structure in the knee and has two main functions. The meniscus helps protect the cartilage in the knee by acting as a cushion between the thigh bone and shin bone, just like brake pads in a car. A meniscus plays a small role in stabilizing the knee and supporting the anterior cruciate ligament. There are two different menisci, one on the medial or inside of the knee, and another one on the lateral or outside of the knee.
Mechanism of injury
A meniscus tear is one of the most common injuries in the knee. The meniscus can tear as a result of an acute injury or as a chronic degenerative issue. In young athletes, the meniscus is often torn during a pivoting or squatting move and can be torn in combination with an ACL tear or other ligamentous knee injury. As we age, the meniscus and structures on the inside of the knee also age and become easier to tear. In patients older than 50-60 years old, the meniscus is often torn by chronic use, simple twisting maneuvers and can be torn if you have significant arthritis within the knee.
Diagnosis and Symptoms
A meniscus tear can cause a pop in the knee, resulting in pain, swelling and localized pain to the joint either medial (inside) or lateral (outside) aspect of the knee. As swelling increases, people can present with posterior (or back of the knee) pain too. Oftentimes, you can still walk with a tear and some can even play sports. Your knee may be swollen in the initial stages of the injury and it may be painful to twist on the knee. A clinical exam by a specialist is an important aspect of evaluation to make sure there are no other injuries. X-rays will help assess the bone structure in the knee and determine the amount of arthritis present. Advanced imaging with an MRI is sometimes used to evaluate the extent of the tear but it does not always need to be performed to diagnose a meniscus tear.
Treatment
The goal with any tear is to calm the initial symptoms, improve function and return you back to your activities. This can be achieved without surgery but sometimes meniscus tears do require surgery. In young patients, less than 30 years of age, surgery is often performed to address the tear due to the importance of this structure in the knee. The goal would be to prevent future development of arthritis in the knee by preserving the meniscus.
Elderly patients and even those greater than 30 years of age, meniscus tears can be treated without surgery and is often recommended to avoid surgery. The meniscus tear does not heal itself, but over the course of 9-12 months, the pain from a meniscus goes away and people are able to regain full function and get back to full athletics within a few months of injury. Non-operative management includes, ice, rest, anti-inflammatories, possible injections, and physical therapy.
Surgical treatment is usually reserved for younger patients and also those that have a locked knee (in which the meniscus is flipped and blocking the motion of the knee). Surgery is usually performed arthroscopically (using a small camera and through poke hole incisions in the knee) with the goal of repairing the meniscus. Sometimes the meniscus can not be repaired and a menisectomy (removing part of the meniscus) needs to be performed.
For more information, please consider the following link that was produced by the AAOS.
https://orthoinfo.aaos.org/en/diseases–conditions/meniscus-tears