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 posteriorly in the knee. The tears occur as the knee is in a flexed weight-bearing position and then the knee is twisted. 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, bringing the injured athlete to a physician’s office.
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. Interestingly, meniscal tears that occur in association with an ACL disruption occur on the lateral side more commonly than on the medial side while isolated and degenerative meniscal tears occur more commonly on the medial side.
- Pain along joint line, usually posteriorly.
- Clicking and sometimes a locking with activities.
- Mild swelling especially following activities.
- Vague aching pain throughout day.
Meniscal tears occur in all age groups. Care of meniscal tears is dependent not only on the age of the patient, but also 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 they are commonly treated by surgical excision of the tear.
Many meniscal tears are small and will not become symptomatic. 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.
N.B.: 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. Further, younger individuals can often have their tear repaired surgically. This possibility decreases the longer surgical intervention is delayed.
Alternative Treatment Options
Partial menisectomies (meniscal excisions) are done arthroscopically and as long as less then 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.
Meniscal tears in younger individuals often can be repaired. The repair process is more involved than removing the tear. However, 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. Unfortunately, in the United States only seven percent of all meniscal tears are repaired.
Rehabilitation following meniscal surgery is relatively straight forward with the reduction of swelling and effusion followed by establishing normal range-of-motion (ROM) and then strengthening. Menisectomies are minimally painful and normal functional ability returns to the knee usually within six weeks, postoperatively. When meniscal repairs are performed, the repair should be protected until the repair has healed. This process usually takes six weeks. Different protocols for protecting the knee during that time frame have been developed and vary from physician to physician.