This is a common question that I encounter in my clinic. Let’s unpack a condition known as crepitus.

If you’ve ever bent down, walked up stairs, or squat down and heard your knees crunch, grind, or pop, don’t worry, you’re not alone. That sound is called crepitus.

While it can be surprising, it’s not always a sign of something serious.

What causes knee crunching and popping?

Several things can make your knees noisy:

1. Gas bubbles in the the joint fluid

The joints are lubricated by a fluid that sometimes forms tiny bubbles. When those bubbles collapse, you can hear a crack or pop similar to cracking your knuckles.

2. Tendons or ligaments moving

As you bend or straighten your knee, tendons and ligaments may snap over the bony structures of the joint, creating a popping sound.

3. Cartilage changes

The cartilage in your knee is meant to provide a smooth surface for your bones to glide over at the joint. With time, or after an injury, that surface may become uneven, causing more crunching or grinding.

When is this normal?

Many people, even healthy young adults, have knees that crunch or pop. Crepitus is generally okay If there’s:

• No pain,

• No swelling, and

• No trouble moving your knee.

When is more attention needed?

Crunching by itself is usually not a red flag. But see your doctor if you have crepitus along with:

• Pain in the knee

• Swelling or warmth

• Locking, catching, or feeling unstable (as if your knee would give way)

• Difficulty with normal activities (walking, bending, climbing stairs)

These signs may point to underlying issues such as arthritis, meniscus injury, or other knee problems.

In Conclusion

Knee crunching and popping is extremely common, and most of the time, it’s nothing to worry about. But if it comes with pain, swelling, or movement problems, further evaluation is needed. Getting an evaluation if you have any concern signs or symptoms can help you keep moving comfortably and prevent bigger problems down the road.