Why Do My Knees Crack, Pop, and Grind? Should You Be Worried?

You bend down to pick up a bag of leaves, and your knees crack. You climb the stairs, and there’s that familiar crunching sound. Or you stand up after watching television and wonder whether the popping came from your knees or the furniture.

With Halloween around the corner, there are plenty of things designed to give you a scare. But should the noises coming from your knees be one of them?

It’s understandable to worry. And if you’re over 40, you’ve probably heard that these noises are just arthritis or “wear and tear.” Sometimes arthritic changes do contribute. But different sounds can have different explanations, and hearing a noise doesn’t automatically mean you’re damaging your knee.

What Causes Your Knees to Crack, Pop, or Grind?

Let’s first understand what those cracks and noises actually are.

“Crepitus” is a term used to describe joint noises or sensations, including cracking, crunching, and grinding. It’s a description, not a diagnosis. But it helps to distinguish an occasional crack or pop from a more persistent grinding sensation.

A painless crack or pop can come from pressure changes in joint fluid. Tendons or ligaments can also make a snapping or clicking sound as they move over nearby structures. These sounds can happen without injury. A sudden pop during a twist or fall, especially with pain or swelling, is a different situation and deserves medical attention.

Grinding and grating, on the other hand, are more commonly associated with changes in joint surfaces, including osteoarthritis. They can also occur with problems involving the kneecap, which slides along a groove in your thighbone as your knee bends. These sounds cannot tell us how much degeneration is present or whether it’s causing your symptoms.

That’s why I pay attention to both the type of noise and what accompanies it.

Is Knee Cracking Without Pain Normal?

A 2025 systematic review in the British Journal of Sports Medicine, involving more than 36,000 participants, estimated that crepitus was present in 41% of the general population and 36% of pain-free participants. What does that mean in plain English? Roughly one in three people without pain had noisy knees. The review also found an association between crepitus and arthritis-related changes on imaging. However, it grouped different noises together. In other words, those findings don’t mean every painless pop is arthritis or that every grinding knee needs to be replaced.

Does Grinding in Your Knees Mean You Have Arthritis?

But what if that crunching or grinding really is related to arthritis? Does that mean your knee is wearing out and you should stop using it?

Not so fast.

A 2025 review in Connective Tissue Research described how inflammation and metabolic changes can disrupt the cells that maintain healthy joints. Your cartilage isn’t simply wearing away like we always thought. It’s living tissue, and changes in its ability to maintain and repair itself can contribute to degeneration. Researchers are also investigating how insulin resistance and blood sugar regulation contribute to osteoarthritis. Mechanical stress matters and still does play a role, but joint changes involve more than simply years of use. That’s why “your knees are getting old” doesn’t adequately explain the noises or tell you what to do about them.

Why Your Knee MRI Doesn’t Always Explain Your Symptoms

Even if those sounds prompt a scan, what shows up may not explain how your knee feels. In the 2008 study “Incidental Meniscal Findings on Knee MRI in Middle-Aged and Elderly Persons,” published in the New England Journal of Medicine, 61% of people with meniscal tears had experienced no knee pain, aching, or stiffness in the previous month. Meaning, a finding that sounds scary on paper doesn’t necessarily mean your knee is in trouble.

When Should You Worry About Noisy Knees?

So how do you know whether those “scary” sounds deserve attention?

When I evaluate a knee, I want to know more than what it sounds like. Can you comfortably bend and straighten it? Does it support you on stairs? Is there swelling? Has your walking changed? These answers help distinguish a noisy knee from one that needs a closer look.

Should You Keep Exercising If Your Knees Crack and Pop?

If your knee makes noise but feels comfortable and supports your usual activities, noise alone generally isn’t a reason to stop moving. Avoiding stairs, squatting, or walking because the sounds scare you can gradually reduce the strength and confidence you need for those activities.

Motion is lotion.

Movement helps circulate the fluid that lubricates your joints, while appropriately chosen exercise builds the muscles that support them. Even with osteoarthritis, clinical guidelines recommend individualized exercise to improve pain and function. Your knee may still make some noise, but if you’re moving more comfortably and confidently, that’s meaningful progress.

How to Treat Knee Grinding and Pain Without Surgery

When those noises come with discomfort or difficulty moving, the next step is to understand why. A movement examination can assess your knee mobility, hip strength, and ankle movement. If neighboring areas aren’t doing their part, your knee may have to take up the slack. Identifying those contributors helps you choose exercises that address the problem instead of simply strengthening everything around a painful knee.

For persistent arthritic knee pain, regenerative therapies such as shockwave may also deserve consideration as an addition to a plan that includes specific movement and strengthening.

Knee Pain Warning Signs That Need Medical Attention

Some symptoms, however, call for medical evaluation. Significant swelling, inability to bear weight, or a knee that locks or repeatedly gives way should be checked. A hot, swollen knee with fever needs urgent care, and persistent, unchanging night pain also deserves attention.

For ongoing discomfort that limits the activities you love, a mechanical pain specialist can help identify what’s contributing and develop a plan to get you moving comfortably again.

The Bottom Line: Noisy Knees Don’t Have to Stop You From Staying Active

This Halloween, if your knees provide their own sound effects, pay attention to what comes with the noise, especially changes in comfort, movement, or stability. A little cracking doesn’t have to scare you out of an active life.

Related Reading

• For the Dad Who Has Everything… Except Good Knees
• Knee Pain After 40? Six Ways to Move Better Without Relying on Medication

Want more help with knee pain? Explore our physical therapy services or watch the Knee Pain Masterclass replay.

Dr. Carrie Jose, Physical Therapist and Pilates expert, owns CJ Physical Therapy & Pilates in Portsmouth and writes for Seacoast Media Group. To get in touch, or get a free copy of her guide to knee pain, CLICK HERE or call 603-380-7902.