A knee meniscus tear is a rupturing of the fibrocartilage meniscus at the top of the tuba in the knee. A meniscus tear is a common knee injury, which can prevent the knee from functioning properly.
Anatomy of the Knee Meniscus
The meniscus is a crescent-shaped shock absorber located in the knee joint between the tibia and femur bones. It is crucial to the health and function of the knee. It provides joint stability and spreads compression forces from the femur over a wider area on the tibia.
There are actually two menisci (plural of meniscus) in the knee:
- The medial meniscus is located on the inner edge of the knee. This elongated C-shaped meniscus bears up to 50 percent of the load applied to the medial (inside) compartment of the knee.
- The lateral meniscus is located on the outer edge of the knee. This circular-shaped meniscus absorbs up to 80 percent of the load on the lateral (outside) compartment of the knee.
In essence, the menisci “fill the gap” between the femur bone and the tibia bone. The femur bone is curved, whereas the tibia bone is flat—the menisci provide joint stability by creating a sort of “cup” for the femur to sit in. Put simply, the menisci cushion the knee.
Meniscal Tear of the Knee
A meniscus tear is exactly what it sounds like—a tear in the meniscal tissue. The tear can be partial or complete and can be mild, moderate, or severe.
- A mild or minor tear is typically a small, incomplete tear that causes some pain and swelling that goes away within a few weeks.
- A moderate tear causes pain and swelling that can grow worse or come and go depending on activity. This can be a partial tear that requires treatment.
- A severe tear means that the meniscus is completely torn and has moved into the joint space, causing the knee to catch, pop, lock, or give way. This requires treatment.
Causes of a Meniscus Tear
The cause of a meniscus tear depends on whether it is an acute tear or a degenerative tear.
- An acute tear of the meniscus is often sports related. It usually results from the combination of weight bearing and twisting. For example, twisting or turning quickly while the foot is planted and the knee is bent can result in an acute meniscus tear.
- Degenerative tears of the meniscus are more common in older people. As we age, the meniscus weakens and loses elasticity—which can result in tears. Often, people with degenerative tears can’t recall a specific event or injury—but they begin experiencing symptoms such as swelling or the knee locking or catching.
Meniscus Tear Symptoms
Depending on the level of injury, a meniscus tear can cause some or all of the following symptoms:
- Pain (often at the side or center of the knee and especially when twisting)
- Stiffness and difficulty bending and straightening the knee
- Movement irregularities, such as catching or locking in the knee joint
- A popping sensation
- Knee feels unstable or gives way without warning
- Pain can become apparent when squatting or rising from a squatting position
Meniscus Tear Diagnosis
The first step in diagnosing a meniscus tear is to discuss the history of the injury and what you were doing when the pain began. If your doctor suspects a meniscus injury, he/she will perform a physical examination to pinpoint the cause of your symptoms. During the physical exam, your doctor will perform a test called the McMurray’s maneuver, which involves applying pressure and moving the knee from straight to bent to straight again to determine which positions cause pain or catching.
In addition, your doctor may use other tests, such as X-rays or MRI (magnetic resonance imaging) to make a final diagnosis.
Meniscus Tear Treatment
Treatment of a meniscus injury depends on several factors:
- Activity level
- Location, type, and severity of the tear
Treatment of meniscus injuries has evolved over the past few decades. Historically, the meniscus was removed when torn; however, research has revealed that this can lead to early degenerative arthritis as well as knock-kneed or bow-legged deformities. Because the meniscus is crucial to the health of the knee joint, most doctors now choose to repair it when possible.
Meniscus Tear Non-Surgical Treatment
Some small meniscus tears will heal without surgery. Non-surgical treatment can include:
- Rest: Your doctor will advise you to avoid activities that aggravate knee pain or require twisting. You may also need to use crutches and continue a regimen of icing the knee to reduce swelling.
- NSAIDs: NSAIDs are non-steroidal anti-inflammatory medications, such as aspirin and ibuprofen. These medications can help reduce pain and swelling.
- Physical Therapy: A qualified physical therapist can provide exercises to help strengthen the muscles surrounding the knee joint in order to stabilize and support the joint.
- Braces and Arch Supports: A knee brace can provide support and help prevent further injury. Arch supports or orthotics can help distribute force more evenly around the knee and potentially decrease the stress on the knee.
If symptoms disappear after 2-3 months, no surgery is needed.
Meniscus Tear Surgical Treatment
Some meniscus tears require surgery, particularly if the symptoms are disabling or the patient is a high-level athlete. There are a variety of surgical approaches for treating meniscus injuries—and the appropriate procedure depends on the location and type of tear.
- Trephination/Abrasion Technique: This procedure is used for stable tears located on the outer edge of the meniscus, where there is good blood supply. The surgeon will create multiple “holes” in the torn part of the meniscus, which promotes bleeding and speeds the healing process.
- Partial Resection: This procedure is used for tears located in the inner two-thirds of the meniscus where there is no blood supply. The surgeon will remove the torn part of the meniscus and leave the rest of the meniscus intact.
- Complete Resection: This procedure involves the complete removal of the damaged meniscus. This technique is only used when absolutely necessary because removal of the entire meniscus increases the forces on the knee joint and can often lead to arthritis.
- Meniscus Repair: In some cases, the meniscus can be repaired with sutures or devices such as arrows, barbs, staples, or tacks. These are referred to as absorbable fixation devices and they join the torn edges of the meniscus so it can heal.
- Meniscus Replacement: Meniscus replacement is a newer technique and is not yet widely used. It involves replacing the meniscus with meniscus from a cadaver or with a collagen implant. As this procedure becomes more widely adopted, it could prevent the degenerative arthritis associated with complete meniscus removal.
All surgical meniscus procedures are performed arthroscopically and usually do not require an overnight hospital stay.
Recovery from Meniscus Tear
Recovery from a meniscus injury depends on the type and location of the meniscus tear and the type of treatment.
Recovering from non-surgical treatment: Patients can expect the following progression:
- Use of crutches for several days (or possibly weeks)
- Begin physical therapy about 2-4 weeks after injury. Physical therapy will be aimed at flexion and extension exercises to build strength. Rotational exercises will be added once the knee is symptom-free.
- Return to activity within 4-6 weeks of injury.
- If symptoms persist after 2-3 months, surgery might be necessary.
Recovering from surgery: Recovery from surgery depends on the type of surgery. Patients who undergo partial resection can expect a similar recovery timeline as those who undergo non-surgical treatment. The recovery from meniscus repair, however, takes longer. Patients can expect to be non-weight-bearing (on crutches) for 1-6 weeks after surgery. What’s more, they may be required to wear a brace for 6 weeks, in order to prevent excessive flexion and extension. Most patients will begin range-of-motion exercises within 1-6 weeks of surgery, depending on the scope of repair. It can take 3 to 4 months before return to vigorous activity.
Learn about the Types and Causes of Common Knee Injuries and Problems
- Types and causes of Knee Injuries and Problems
- Knee Anatomy
- Knee Pain and Injury Symptoms and signs
- When to Call your Doctor
- Treatment for Common Knee Injuries and Problems
- Ice or Heat for An Injury?
- Meniscus Tear
- Preventing Knee Injuries
- Knee Replacement
Our goal at OSMI is to provide our patients quality, cutting-edge orthopedic treatments, both surgical and non-surgical. If you have questions about knee arthroscopy or surgery, knee joint pain, or physical therapy, please submit an online appointment request or contact our office at 817-529-1900.