Meniscal Tear of the Knee
What is a meniscal tear of the knee?
A torn meniscus is one of the most common knee injuries. When people talk about torn cartilage in the knee, they are usually referring to a torn meniscus.
The meniscus is a rubbery, C-shaped piece of cartilage that cushions the knee, provides stability and helps distribute body weight across the knee joint. Each knee has two menisci, one at the outer edge (the lateral meniscus) and one at the inner edge (the medial meniscus). The type of treatment available for a meniscus tear depends, in part, on where the tear occurs. A torn meniscus can prevent the knee from functioning normally. Left untreated, it can lead to early arthritis of the knee joint.
How does a tear occur?
Meniscus tears happen to people of all ages and activity levels.
Acute tears result from any activity that forcefully twists or rotates the knee. Athletes who play high-demand, stop-and-go pivot sports are most vulnerable. Contact athletes, such as football players, may have added risk. Meniscus tears are extremely common in young women athletes, and often occur together with injuries to the anterior cruciate ligament (ACL).
In middle-aged adults, the cause is usually degenerative changes in the knee. Cartilage weakens and wears thin over time. Aged, worn tissue is more prone to tears. Running, squatting or rising from a chair can tear the meniscus in this population. In older patients and patients with knee arthritis, meniscal tears are often present but may not be responsible for symptoms.
What are the symptoms of a meniscal tear?
You may feel a pop at the time of your injury. Most people can still walk on their injured knee and many athletes keep playing with a tear. Over the next few days, your knee will gradually become painful. Stiffness and swelling are less common features than pain. Other symptoms include pain along the joint line, limited motion due to pain, catching, clicking, and locking. A locked knee in which the knee won't straighten because displaced meniscal tissue is trapped between the joint can occur. Your knee might feel unstable, as if it's going to collapse, and you may have difficulty squatting. Patients experiencing root tears may not have classic meniscal signs but typically will have a sudden increase in knee pain after activity with or without swelling. A high index of suspicion for these tears is needed to make a timely diagnosis.
How is a meniscal tear of the knee diagnosed?
In addition to the history and a physical exam, MRI is the most effective test to confirm the diagnosis of a torn meniscus.
What is the treatment?
Treatment depends on the type of tear, location (outer edge or inner edge), severity and injury to other structures such as the ACL. Treatment options include:
- Conservative management. If your tear is small and on the outer edge of the meniscus, it may not require surgical repair. As long as your symptoms do not interfere with daily living and your knee is stable, non-surgical treatment may be all you need. This includes rest, observation and activity modification. Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen reduce pain and swelling.
- Operative management. If your injury is acute or you want to return to high-level athletics as soon as possible, surgery is necessary. Because the meniscus aids in load transmission, stability, shock absorption, position and movement, repair is the treatment of choice. But most tears are not repairable. Repair is an option when the tear is on the outer edge of the meniscus where there is still blood flow to help with healing. Most reparable tears are associated with knee ligament injuries especially ACL tears. Root tears are tears that occur where the meniscus attaches to the bone. These specific types of tears are best treated by repair if the tear is acute or subacute with good quality tissue. This repair requires re-attaching the meniscus to the bone. Trimming root tears does not result in improved symptoms. When the tear is unstable and located on the inner-edge, with no blood flow, the damaged tissue must be removed. The vast majority of patients have their meniscus removed rather than repaired if surgery is indicated to improve symptoms and balance the meniscus.
Surgical options include arthroscopic meniscectomy to remove the torn meniscus, or open or arthroscopic surgery to repair it. Recovery time varies depending on the type of surgery you have. Rehabilitation includes special exercises to restore range of motion, strength and mobility.