Your knee is made up of many important structures, any of which can be injured. The most common knee injuries include fractures around the knee, dislocation, and sprains and tears of soft tissues, like ligaments. In many cases, injuries involve more than one structure in the knee.
Pain and swelling are the most common signs of knee injury. In addition, your knee may catch or lock up. Many knee injuries cause instability — the feeling that your knee is giving out from under you.