The most common injury to the young athletic knee is a tear of the medial meniscus. There are two menisci within each knee, and they function to distribute stress during weight-bearing activities. By distributing stress evenly, menisci can limit articular cartilage surface damage, which is the beginning of arthritic degeneration. Menisci also function to help stabilize the knee and to increase the smooth motion of the knee joints.
Meniscal tears most often occur behind the knee. The tears occur when the knee is twisted while in a flexed, weight-bearing position. This creates a shear force on the meniscus, causing it to tear. Unfortunately, meniscal tears usually do not heal themselves once they have reached a substantial length (1 cm). When meniscal tears of this length or greater occur, mechanical problems and pains are caused and require medical attention.
Meniscal tears often occur in association with other injuries to the knee. Perhaps the most common of these is an anterior cruciate ligament (ACL) tear.
Typical symptoms include:
- Pain along joint line, usually posteriorly
- Clicking and sometimes a locking feeling with activities
- Mild swelling, especially following activities
- Vague, aching pain throughout the day
Care of meniscal tears is dependent on your age, as well as the size, length, and quality of the tear. As an athlete ages, the meniscus becomes less vascular and, therefore, less able to heal and/or be repaired. For this reason, degenerative meniscal tears usually occur in individuals aged 35 and over and are commonly treated by surgical excision of the tear.
Many meniscal tears are small and will not become symptomatic, but tears that are big enough to cause symptoms can be treated non-operatively, especially in older individuals. A course of activity modification followed by therapy and a gradual return to sports is successful in approximately 50 percent of these individuals. The tear itself does not heal but rather is “ground-down” to a point where it is no longer symptomatic. When this does occur, a patient feels better within three weeks and is able to return to normal activities by six weeks.
Note: This form of treatment is not recommended in young, healthy individuals as this age group has a greater potential to worsen their tear by walking or playing on it. Younger individuals can often have their tear repaired surgically. Provided the tissue that is torn is not itself damaged, the repair can be performed, saving the overall function of the meniscus. Ultimately, this can lead to a longer, higher functioning ability of the knee and presumably less likelihood of post-traumatic arthritis. However, this possibility decreases the longer surgical intervention is delayed.
Alternative treatments can include glucosamine, hyaluronic acid, and non-steroidal anti-inflammatory medications (NSAIDs).
If surgical intervention is needed, partial meniscectomies can be done arthroscopically. As long as less than 20 percent of the meniscus itself is removed, little long-term detrimental effect to the knee is caused. Removing larger portions of the meniscus, however, can be a predecessor to progressive, degenerative arthritis.
Rehabilitation following meniscal surgery is relatively straight forward with the reduction of swelling and effusion followed by establishing normal range-of-motion (ROM) and strengthening. Meniscectomies are minimally painful and normal functional ability returns to the knee usually within six weeks, postoperatively.