When do Meniscus Tears Require Treatment?

The knee is one of the most complex and commonly injured joints in the body. The knee joint is made up of the femur (thigh bone), tibia (shin bone), and patella (knee cap). The meniscus lies between the femur and tibia and protects the articular cartilage that lines the ends of these bones. There are two menisci in each knee, one on the inside (medial meniscus), and one on the outside (the lateral meniscus). They are made up of strong fibrocartilaginous tissue that is molded in between the femur and tibia. This tight fit allows for an even distribution of forces from the femur to the tibia when weight-bearing and performing athletic activities.

A healthy meniscus functions as a shock absorber allowing the smooth surfaces of the knee to glide on. In addition, it serves as a secondary stabilizer when participating in sports requiring a sudden change of direction, cutting, and pivoting. Given the function of the meniscus, injuries are exceedingly common, particularly in active individuals.

Different Types of Meniscus Tears

Meniscal tears are amongst the most frequently reported injuries to the knee joint. Meniscus tears can be separated into two major types; traumatic and atraumatic (or degenerative) tears. Traumatic or acute tears typically occur with rotational or twisting injuries of the knee in a younger patient population. The injury can occur with or without contact and often happen during sports activities such as skiing, football, basketball, and soccer. In contrast, degenerative or atraumatic tears are more commonly found in older populations and are caused by increased meniscal and cartilage fragility that occurs with aging. In fact, more than 60% of patients over the age of 65 have been found to have meniscus tears. Thus, degenerative tears may be present long before they become painful, and minor injuries or sudden changes in activity may lead to an increase in symptoms.

There are several different types of meniscus tears. Tears are often described as partial thickness, meaning it does not go all the way through the entire meniscus tissue, or full-thickness, meaning the tear goes all the way through. Tears are further described by their appearance. Common types of traumatic tears include bucket handle tears, flap tears, and radial tears.

Symptoms of Meniscus Tears

Symptoms of each type of meniscus tear can be similar. The most common symptom is pain within the joint. Patients who experience acute or traumatic meniscus tears will commonly recall an injury, after which the knee became inflamed and swollen. When the meniscus is torn, the damaged piece will move irregularly within the joint and often manifests in pain along the inside or outside of the knee between the femur and tibia bones. The damaged piece can also get trapped in an abnormal position, resulting in catching or locking sensations and a reduced range of motion. The pain is often felt while bearing weight on the affected knee, and when twisting or pivoting on the knee during activity.

After a knee injury, it's important to discontinue activities that worsen or cause continued knee pain. The affected knee should be iced for 20 minutes five times a day until the swelling subsides. The knee should be compressed with an ACE bandage or compression stocking to prevent continued swelling. The affected leg should be elevated above the heart to encourage the flow of blood away from the knee. Over-the-counter anti-inflammatory medications can also be taken as prescribed to reduce the pain and swelling. If needed, crutches should be used to offload the knee, and to assist with stability.

Persistent knee pain and swelling despite home treatment should be evaluated by a physician. A detailed clinical history, physical examination, x-rays, and MRI are necessary to successfully diagnosis a meniscus tear. This physician will perform a thorough clinical history, determining when and how the pain started, reviewing the mechanism of the injury, and inquiring about the current symptoms. A physical examination should then be performed to evaluate for pain in the area of the meniscus, and specific exam maneuvers should be done to detect meniscus injuries. X-rays are often ordered to rule out any bony injury, arthritis, or other conditions. Ultimately, an MRI is obtained to confirm a diagnosis of a meniscus tear and assess the extent of any other damage within the knee.

Treatment Options for a Meniscus Tear

The treatment for meniscus tears is dependent upon the type of tear, size of the tear, and location of the tear. Most often, non-surgical treatment can be provided which includes rest, anti-inflammatory treatment, and guided physical therapy to strengthen the supporting musculature of the knee. If the pain and swelling do not respond to this treatment, a corticosteroid injection can be considered to further reduce symptoms and aid in more meaningful participation in physical therapy. If symptoms persist despite this, surgery can be considered.

For some meniscus tears, such as bucket handle tears in young patients or meniscus root tears in older patients, surgical repair is recommended prior to conservative treatment to increase the rate of healing, maintain the health and longevity of the knee, and prevent the early onset of arthritis. If surgery is required, it is typically done arthroscopically. Knee arthroscopy is a minimally invasive procedure where small incisions are made and a fiberoptic camera is used to visualize the knee joint. While visualizing with the camera, other instruments are used to carefully remove the torn, non-functional meniscal fragments. In the case of a meniscal repair, specialized devices are used arthroscopically to deploy sutures to tie the meniscus fragments back together.

Given the importance of the meniscus to the overall health and longevity of the knee joint, only the damaged portion of the meniscus is removed. Depending on the type of tear, location, and extent of the tear, some tears are repairable. If this is the case, every attempt is made to repair any part of the meniscus that has the potential to heal.  However, not all meniscus tears are repairable, and attempting repair for a tear that is unlikely to heal could result in additional surgery to remove the unhealed portion.

Post-operative rehabilitation is dependent upon whether the meniscus was able to repair. If the meniscus was trimmed, patients can weight bear immediately without a brace. Physical therapy is begun the week of surgery, and patients can expect to return to the majority of their activities within 6-8 weeks of surgery. Patients who have their meniscus repaired need to limit weight bearing on the knee for 4-6 weeks after surgery, wear a brace to protect the repair, and allow time for healing. After this time, they will focus on strengthening, reconditioning, and gradually returning to their prior activity level and can expect a return to sport around four months.