The knee is a joint
that joins the thigh bone (femur) to the top of the shin bone (tibia). It is made
up of bones,
, muscles,
, and tendons. These parts work together to make the legs bend, straighten,
and swivel. A knee injury can damage one or more parts of the knee.
What Causes Knee Injuries?
Teens may injure a knee in a fall or accident. Active and athletic teens might
have overuse knee injuries. These
happen when someone trains too much or makes repetitive motions involving the knee.
Osteochondritis dissecans: when a small piece of bone in the knee loses blood
supply and breaks off
bursitis: swelling of one
of the fluid filled sacs that cushion the knee.
What Are the Signs & Symptoms of a Knee Injury?
The signs and symptoms of a knee injury depend on the cause. Most knee injuries
cause pain. A knee injury may also lead to the knee feeling weak, "giving way,"
or "locking." Someone with a knee injury might not be able to fully bend
or straighten the knee. The injured knee may be swollen or bruised.
How Are Knee Injuries Diagnosed?
To diagnose a knee injury, health care providers ask about how the injury happened
and what symptoms it causes.
The health care provider will do a physical exam that includes pressing on the
knee and legs and moving them in certain ways. These tests can show what part of the
knee is injured.
When jumping, bend the knees while landing. This takes pressure off the ACL and
prevents injury.
If you cut laterally or pivot frequently (as in soccer),
crouch and bend at the knees and hips to reduce the chances of an ACL injury.
If you play just one sport, conditioning and training year-round — even if it's
at a lower intensity than during the competitive season — can help you stay in shape
and make an injury less likely.
What Else Should I Know?
If your knee hurts, it is important to know why. Go to a health care provider to
find out what's causing the pain and to get treatment.