When a meniscus tears, there may be stiffness or swelling, a popping sensation may be heard and there is pain in the knee, particularly when rotating or twisting it, according to Mayo Clinic. It may be difficult to fully straighten the knee, and the knee may feel as if it is locked into position.
The knee is equipped with two menisci, which are C-shaped rubbery discs that work to cushion the knee and keep it steady, according to WebMD. It also balanced weight across the knee, so when it is torn, the knee doesn't work as it should.
Turning or twisting rapidly while the foot is stationary and the knee is bent is the most common way that the meniscus becomes torn, reports WebMD. Minor tears of the meniscus may go away within a few weeks and only require rest, wrapping the knee with a supportive bandage or perhaps physical therapy. Moderate tears of the meniscus may cause pain and swelling that slowly gets worse over a period of a few days, and if not corrected, it may present problems for years to come. More severe tears may interfere with daily living, since the affected knee may give way beneath the injured person's weight or feel wobbly when walking. Severe tears may require surgery to remove or repair the meniscus.