One common cause of a torn knee ligament is stopping suddenly in the middle of a run, claims WebMD. Other causes are a sudden twisting of the knee while the foot is planted, a direct injury to the knee and jumping and landing on the knee when it is flexed.
The knee has four ligaments that help to give it strength and stabilize it: the anterior cruciate ligament, or ACL; the posterior cruciate ligament, or PCL; the lateral collateral ligament, or LCL and the medial collateral ligament, or MCL. These ligaments are also at risk for injury, according to WebMD. They are most often injured in contact sports, such as football.
Often a person may actually hear a "pop" and experience severe pain right away when he injures a knee ligament, states WebMD. The area may swell, and the person may not be able to put his weight on the knee. The knee may also feel unstable.
Though a knee ligament injury may seem dire, many heal with only conservative treatment, says WebMD. The patient can benefit greatly from the RICE procedure. This means the knee should be rested, iced, compressed and elevated. Anti-inflammatory medications can help alleviate pain, and a knee brace can help stabilize the knee and prevent additional injury.