Symptoms:

• A grating or grinding sensation when the knee is extended
• Knee pain in the front of the knee that worsens after sitting for a long period of time
• Knee pain that worsens with using stairs or getting out of a chair
• Knee tenderness

Signs and tests:

The doctor will perform a physical examination. The knee may be tender and mildly swollen, and the kneecap may not be perfectly lined up with the femur (thigh bone).

When you straighten your knee, a grinding sensation may be felt below the kneecap. Pressing the kneecap when the knee is straight may be painful.

X-rays are usually normal, although a special x-ray view of the kneecap may show signs of arthritis or tilting.