Your knee: it's the biggest joint in your body, made up of a lot of parts that
can get injured in all kinds of sports. The knee connects the lower end of the
thighbone (femur) to the upper end of the shinbone (tibia). Several
large ligaments - strong, elastic bands of tissue that join bone to bone - make
this connection, bracing and controlling the motion of the joint. The kneecap
(patella) slides in a groove at the end of the thighbone; it protects
the knee and gives leverage to various leg muscles. Cartilage at the ends of
the leg bones helps to cushion the joint, like a shock absorber.
Sprains - stretched or torn ligaments - are an especially common knee injury;
the anterior cruciate ligament (ACL) is the one most often damaged. This
can happen, for example, when you change direction quickly, twist a leg or fall,
slow down when running, or land from a jump. Typically, a torn ACL will be immediately
disabling: you'll feel or hear a "pop," and the knee seems to "give
way." Even though it might not be painful, see a doctor right away. Surgery
may be necessary.
Knee pain can also come on gradually from overuse of the joint. For example,
"patello-femoral syndrome," or pain caused by the kneecap being pushed
against the sides of its groove, can occur if you do a lot of running. The pain,
either sharp or dull, is usually felt in the front of the knee. Squatting or
walking down stairs often makes it worse, and you might feel a grinding or "clicking"
in the joint. A sports medicine specialist can help you to rebalance the kneecap
and prevent further pain through proper training, stretching, and strengthening
exercises.