Health Tip: Feeling Weak in the Knee?

(HealthDay News) -- Unstable kneecap occurs when the kneecap slides off the groove at the end of the thighbone.

The American Academy of Orthopaedic Surgeons says typical symptoms include:

• Buckling of the knee and inability to support body weight.
• Kneecap is located off to one side.
• Knee tends to catch when moved.
• Pain at the front of the knee that worsens when you're active.
• Stiffness or swelling in the knee, or pain when sitting.
• Knee makes a cracking or creaking sound when you move.