What is the meniscus?
The meniscus is a C-shaped disc of cartilage. Each knee has two menisci, one on the inner portion and the other on the outer portion of the knee. The menisci function as shock absorbers and cushions to prevent wear and tear inside the knee. They sit between the tibia (shin bone) and femur (thigh bone) and prevent these bones from rubbing together. They also help distribute weight equally for balance and stability and to facilitate smooth and controlled movements of the knee.
A torn meniscus is one of the most common knee injuries and one of the most frequent reasons for knee surgery. Meniscus tears also frequently occur with other knee injuries, especially anterior cruciate ligament tears.
What causes a meniscus tear?
Meniscus tears can be acute, sudden tears that occur during sports. Acute tears are the result of aggressive movements in which the knee twists or rotates during pivoting, kneeling, or squatting frequent in soccer, tennis and basketball.
A degenerative tear is the result of cartilage degeneration over time, caused by chronic wear and tear that accumulates with age. As patients age, the cartilage can become stiff and brittle. Tears can result from twisting motions or hyper flexing the knee (excessive bending). Everyday activities including getting in and out of a car, squatting, and heavy lifting, can also cause tears. Degenerative meniscus tears are more common in older individuals, affecting 6 out of 10 patients over age 65.
What are the types of meniscus tears?
There are many different types of meniscal tears. Broadly, tears can be described as partial thickness, meaning the tear is limited, and full thickness, meaning the tear goes all the way through the meniscus. Tears are also described based on their appearance. Common types of traumatic tears include root tears, bucket handle tears, vertical tears, and radial tears.
The location of the tear of the meniscus determines the ability of tear to heal on its own. The meniscus has three zones of vascularity (blood supply). The red zone is the outer perimeter of the meniscus and has an adequate blood supply to facilitate healing. The red-white zone is the transitional area in the middle of the meniscus with an intermediate blood supply and capacity for healing. Finally, the white zone is the innermost part of the meniscus with a limited blood supply and limited ability to heal.
What are the symptoms of a torn meniscus?
Common symptoms include a popping sensation, localized pain and swelling on the inside or outside of the knee depending on the location of the tear. Other symptoms include stiffness, clicking, catching, or locking. Patients can also report instability, reduced range of motion, and difficulty walking. Pain may present when the patient returns to daily activities like walking, running, and climbing stairs, with symptoms of intermittent swelling, instability, and locking of the knee. Over time, a torn meniscus can predispose the affected knee to the development of osteoarthritis.
How is a meniscus tear diagnosed?
The combination of a detailed history, comprehensive physical examination, x-rays, and an MRI is the key to successful diagnosis of a meniscus tear. Frequently, a torn meniscus can be diagnosed with a physical exam and special tests. X-rays cannot detect a tear, but will identify fractures, arthritis, and other conditions. An MRI can be ordered to confirm a diagnosis and provide an assessment of the extent of the damage, and any associated arthritic conditions.
What are the treatments?
Treatment of a meniscus tear is determined by the appearance, location, size and depth of the tear.
- Tears in the inner one third of the meniscus called the white zone are generally treated by removal of the meniscus, called a meniscectomy. A partial meniscectomy can trim away damaged tissues.
- Tears in the middle and outer thirds of the meniscus have a good blood supply, which provides the necessary biological substances for healing following surgical repair.
Knee Arthroscopy is the preferred surgical procedure because it is minimally invasive and allows the surgeon to see inside the knee and treat with miniature surgical instruments. Meniscus repair involves stitching together the torn pieces of tissue.
In cases where the meniscus has previously been largely removed, Dr. Godin may recommend a meniscal transplant for patients younger than 55 who live an active lifestyle. The damaged meniscus is replaced with donor cartilage. However, older patients with severe damage a total knee replacement may be the best option.
After surgery, the patient will be in a brace and crutches for 4 to 6 weeks. Physical therapy will begin the dsay after surgery. Return to sports will depend on how quickly you heal. Dr. Godin will determine when it is safe for you to return to sports. Recovery time depends on the type of procedure you have had. Generally, recovery from a meniscus repair takes 4-6 months. However, recovery from a meniscus transplant can take 6-12 months.