Knee instability or buckling

An unstable knee may not support your weight or may "buckle" when you try to walk on it. Trying to move the joint may cause severe pain. A child will protect his or her leg or may be unable to walk or stand.

Knee instability or buckling can have many causes, such as:

• A fracture of the kneecap, the femur, or one or both of the bones of the lower leg.
• A dislocation of the kneecap.
• Injury to the ligaments and tendons that support the kneecap.
• A tear in the tissue that cushions the inside of the joint (meniscus).
• An old injury that never completely healed or that healed incorrectly.

Treatment for knee problems that cause instability or buckling may include medication, cold, heat, compression bandages and braces, physical therapy, and in some cases surgery.

Call your doctor if knee instability or buckling causes severe pain or interferes with your ability to walk or stand.