Anatomy of the Knee
Your knee is a hinged joint in which three bones meet: the femur, tibia, and patella (knee cap). There are two cartilage disks between the femur and tibia that make up the menisci: the medial meniscus on the inner side of the knee and the lateral meniscus on the outer side. The menisci are tough and rubbery, and act as shock absorbers to stabilize and cushion the knee joint. The ends of the femur and tibia are covered with another type of cartilage called articular cartilage which is a slippery substance that allows the bones to glide smoothly past each other.
Description of Meniscus Tears
There are many ways to tear a meniscus. Acute tears, such as flaps or bucket-handle tears, often result from specific trauma to the knee. Degenerative meniscal tears occur when the tissue has simply degraded over the years, often resulting in frayed edges. Any of these tears can cause a loss of the protective function of the meniscus, which in turn can lead to development or progression of knee osteoarthritis. Repairing the meniscus can restore this protective function. If repair is not possible, trimming out the tear can eliminate the symptoms of the tear.
Causes of Meniscus Tears
Although athletes playing contact sports are at higher risk for meniscal tears, anyone of any age can tear a meniscus. Some tears are caused by a specific incidence of trauma to the knee, such as a tackle or an awkward squat. The majority of tears are caused by degeneration of the tissue over time, and are most often seen in people over 40. Meniscal tissue is poor at regeneration due to limited blood supply, which leads to wearing and weakening over time. Degenerative meniscus tears can occur from something as common as getting up from a chair.
The most common symptoms of meniscus tears are:
- Knee pain, especially when going down stairs or getting up from a seated position
- Stiffness and swelling
- Clicking or popping inside the knee
- Loss of range of motion
- Knee locking
You may feel a pop in the knee when you tear a meniscus.
If you suspect you have a meniscus tear, the best immediate treatment is to follow the RICE protocol, in which you:
- Rest, taking a break from the activity that caused the injury
- Ice the knee for about 15-20 minutes at a time throughout the day
- Compress the knee to prevent additional swelling with an ACE bandage
- Elevate the leg above the heart when resting
Over-the-counter anti-inflammatories can also be used to alleviate pain and swelling.
Diagnosis of Meniscus Tears
Your doctor will discuss your symptoms and examine your knee. Tenderness along the joint line where the meniscus sits often signals a tear. The doctor will probably also perform the McMurray test, in which the knee is bent then straightened and rotated. A clicking sound during this movement indicates a meniscus tear.
Other knee problems cause similar symptoms, so your doctor will often order imaging tests to confirm the diagnosis. Images such as x-rays and MRIs can also help identify fractures and other concurrent injuries.
Treatment Options for Meniscus Tears
Treatment depends on several factors, including amount of pain, effects on quality of life, the type of tear you have, age, and how long you have been experiencing symptoms.
Non-surgical Treatment of Meniscus Tears
Some meniscus tears can be treated non-surgically. These are usually small and occur on the outer edge of the meniscus, and such tears can sometimes heal on their own. The doctor will recommend that the patient follow the RICE protocol, and may have you use crutches for a period of time to prevent weight bearing on the injured knee.
Surgical Treatment of Meniscus Tears
If your symptoms do not subside with non-surgical treatment, your doctor may suggest arthropscopic surgery to either repair or trim out the tear. Younger patients are better candidates for repair, as they tend to have better blood flow to the meniscus and better healing potential. This procedure has a longer recovery period as the repaired meniscus must be protected at first to allow healing. Adults generally are better candidates for partial meniscectomy, which involves trimming out the torn section of meniscus. The recovery period for this procedure is fairly short, perhaps only a week or two if the knee is otherwise uninjured.
In a small number of patients, meniscal transplant surgery may be an option. The goal of a meniscal transplant is to relieve pain and prevent the development of osteoarthritis in young, active patients with a severely damaged meniscus by replacing the cushion before the articular cartilage can be damaged. The eligibility requirements for patients to receive meniscal transplants are very strict, so the procedure is relatively uncommon.
Complications of Surgery
Arthroscopic surgery for a meniscus tear is a fairly low-risk procedure, but any surgery can have complications. Infection is a risk with any procedure in which an incision is made, but knee scopes have a very low infection rate (much less than 1%). Blood clots are also a concern with any procedure involving the knee. Depending on medical history, some patients may be placed on aspirin or other blood thinners for a short time to minimize this risk.
After surgery, your doctor may brace or otherwise immobilize your leg during the initial healing period, especially if you had a meniscus repair. After swelling subsides, regular exercise is necessary to restore knee mobility and strength. For the most part these exercises can be done at home, but your doctor may recommend physical therapy.
- How do you determine which meniscus tears need surgery?
Younger, more active patients are better candidates for meniscus surgery. Weight bearing X-rays of the knee and MRI are important to determine the amount of arthritis in the knee, because a knee with advanced arthritis may not improve much with a surgery to remove a torn meniscus.
- Am I too old for meniscus repair?
The decision for meniscus repair is based on many factors, including age. The type, size, location, and orientation of the tear are considered, as well as patient age, activity level, and associated conditions of the knee such as arthritis and instability. Younger patients are better candidates for repair, but I would consider repair in an older, active patient with an otherwise healthy knee.
- When can I go back to work after partial meniscectomy?
Most patients with a desk job will be able to go back to work after only a few days. It may take 2 weeks to return to a more physically demanding job. If there are other problems with the knee such as moderate arthritis, then return to work may be delayed.
- If my meniscus is repaired, when can I play sports again?
Meniscus tears that are repaired must be protected after surgery to allow the body to heal the meniscus tissue. Generally, weight bearing is restricted in some form for about 6 weeks. It usually takes 4 months to return to full athletic activity after a meniscus repair.
- How can I prevent meniscal degeneration?
Meniscal degeneration is a normal part of aging, and may not be completely preventable. Keeping your body weight at healthy levels is probably the most important factor in protecting the meniscus.
If you have more questions, please call my office at 502-394-6341.