Popping Joints: Crepitus and What Causes It

Knees that clack when you stand up. A neck that crackles when you turn your head. Ankles that pop when you rotate them. We’ve all heard these sounds, and they may happen more often as we get older — but are they a cause for concern?

Primary care sports medicine specialist Wesley Baker, DO, and chiropractor Andrew Bang, DC, share why your joints crackle and pop and when you should seek medical care.

What is crepitus?

“Crepitus” is the medical term for the popping, crunching, scraping and grating sounds that may occur when you’re moving a joint.

These sounds can be alarmingly loud — around 83 decibels. That’s about the same volume as a running garbage disposal or a diesel truck rolling along at 40 miles an hour. So, it’s no wonder many of us think something could be wrong when our joints crack.

Why do my joints crack?

Joints, like the ones in your fingers, knees and elbows, can pop for a few different reasons. The most common causes involve:

• Gas moving inside your joints: Synovial fluid lubricates your joints and contains gases like nitrogen and oxygen. “This fluid is like motor oil for your joints,” says Dr. Bang. Changes in joint pressure can cause gas pockets to form or shift, creating crepitus.
• Ligaments or tendons moving: These connective tissues can sometimes slide or snap over bones and each other as you move. “You may feel that sensation in your ankle when you move it, or in your knee when you stand up,” describes Dr. Bang.
• Skin and fascia separating: Fascia is connective tissue that creates a lubricated, protective barrier for your muscles. When skin is pulled or moves quickly, it can separate from the fascia and create a change in pressure that makes a popping sound.
• Wear and tear on your joints: Normally, cartilage helps the bones in your joints move past each other smoothly and safely. But this natural lubricant can start to wear away due to normal age-related changes or osteoarthritis. “You get more of that popping noise as your bones rub against each other,” explains Dr. Baker.

When to worry about popping joints

There are two main scenarios where a popping joint requires a trip to a healthcare provider:

• You experience pain or swelling in a joint.
• You often feel the need to crack a joint because it’s stiff, tight or uncomfortable.

“If crepitus is coupled with consistent pain or swelling, that can be a sign something is wrong,” says Dr. Baker. “Joint noise is typically OK if your joint isn’t painful. But if there’s pain, you may have an injury that requires treatment.”

Habitually cracking your joints can also signal that your joints need care and attention.

“We feel the need to crack joints because the pressure builds up in the joint over time,” adds Dr. Bang. “The joint could be getting stuck in one position or tightening up, so you feel the urge to crack it.”

Cracking feels good because it increases the joint’s range of motion. But if cracking your joints becomes a habit, you risk getting too much of a good thing. Ligaments and tendons loosened by constant cracking won’t protect you from injury as well as they should.

A joint effort

You can’t stop crepitus entirely. It’s both a function of our anatomy and an expected part of aging. But if you’re not feeling pain, swelling or discomfort, then your cracking joints shouldn’t be a source of concern.

Just remember to stay active and practice good posture, as those are the best ways to keep your musical joints in tune.

“We say ’motion is lotion’ — the more you move, the more your body lubricates itself,” shares Dr. Baker. “If you’re sitting around for long periods or not very active, you can end up with stiff joints and discomfort. That’s why exercise is so important to the longevity of your joints.”