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Knee Pain Health Center

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What Is Your Knee Telling You?

By Lisa O'Neill Hill
WebMD Feature
Reviewed by James Kercher, MD

Do your knees make noise? There's probably no reason for concern. Popping and cracking sounds usually aren't signs that something's wrong.

“A lot of joints crack and the knees are a really common joint to crack,” says David McAllister, MD, director of the UCLA's Sports Medicine Program. “Most people have knees that crack when they squat down or go through the full arc of motion. We generally don’t worry about cracking or popping when it isn’t associated with pain or swelling.”

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Runner’s Knee

As the name suggests, runner's knee is a common ailment among runners. But it can also strike any athlete who does activities that require a lot of knee bending -- like walking, biking, and jumping. It usually causes aching pain around the kneecap. Runner's knee isn't really a specific injury. It's a loose term for several specific disorders with different causes. Runner's knee can result from: Overuse. Repeated bending or high stress exercises such as lunges and plyometrics can irritate...

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Curious why your healthy knees might be making noises? As we age, the tissue that covers the bones, called cartilage, can develop uneven areas. When we squat or stand, sounds come from these rougher surfaces gliding across each other. It could also be the tissue that connects bones to other bones, called ligaments, tightening as you move, or the joint lining moving over bones.

If you have cracking or popping that does cause pain or swelling, though, see a doctor. It can be a sign of:

  • Meniscus tears. The meniscus is a rubbery C-shaped disc that cushions your knee and acts as a shock-absorber. It also helps spread weight evenly so your bones don’t rub together. Tears to the meniscus are often caused by sudden twisting or other things you might do while playing sports. In young people, tears usually happen during a traumatic event, but as we age the meniscus can tear more easily.
  • Cartilage injury or wear. Sometimes the cartilage covering of our bones can be injured, causing a piece to break off and catch in our joint. Typically the knee will respond to this injury by swelling or catching. Cartilage in your knee can also wear thin or break down, commonly known as arthritis. Some people say it feels like their knees are grinding when they move. Osteoarthritis is the most common kind of arthritis. It usually affects middle-aged and older people.

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