Imagine it's your first time alpine skiing. You come down the hill too fast, hit a bump, catch one ski in the snow and have your leg twisted outward. If you're unlucky, the ski patrol might wind up taking you the rest of the way down. Compression combined with rotation of the knee joint, whether it's during a skiing accident, a basketball pivot or something as ordinary as slipping on ice, is one of the most common causes of a meniscal tear, which is a tear in the fibrocartilage that makes up the two menisci in each of your knees.
People who have this injury often feel a dull and constant pain in and around the knee when resting, but a sharp pain when walking or bending the affected leg. If the injury is severe, they may also experience debilitating pain that leaves them unable to walk. There may be some swelling as well, but this may take a few hours after injury before becoming apparent.
If you've got all those symptoms but don't remember experiencing any awkward leg twisting, you could still have a meniscal tear. In fact, healthcare practitioners distinguish between traumatic tears, like those that happen in skiing accidents, and degenerative tears, which most commonly develop as people age.
To understand the difference between the two causes, think of the two menisci (the lateral, or outer meniscus, and the medial, or inner meniscus) working together to form a shock absorber. Traumatic events can overload this shock absorber, causing partial or complete rips. Degenerative changes, on the other hand, simply wear it out.
The latter occurs when the tissue that makes up the menisci dries out, becoming less elastic and less effective at absorbing forces and providing stability. This drying out is a natural aging process that researchers don't yet fully understand. It can make people susceptible to tears, even when they're just performing relatively routine, non-stressful activities such as dancing or squatting.
While anyone at any age can suffer a traumatic meniscal tear, young adults appear to be more susceptible because of their more active lifestyles. Degenerative tears, on the other hand, are most common in people in their late 50s or early 60s. Regardless of whether you're suffering from a degenerative or traumatic tear, however, studies suggest that conservative care is often more effective than surgery for this type of condition.
Surgery may be necessary for severe tears, however. It involves removing part of the meniscus and suturing or scaffolding a graft, possibly a collagen implant, in the knee to promote the growth of new tissue. This surgery is a last resort, and while it generally has good results, non-invasive care should be your first choice as it involves a lesser risk of side effects.
If you suspect a meniscal tear, see your healthcare practitioner as soon as possible regardless of the amount of pain you feel. Tears to the menisci commonly occur with additional injury to surrounding structures, so your healthcare practitioner should perform a thorough examination. Also, because there is poor blood supply to the inner edges of the menisci, tears in this region are infamous for healing poorly. The sooner you seek care, the better.