It is one of the most common worries we hear in Pocatello, and it usually arrives the same way.
“My knees crack every time I go down the stairs.”
“They grind when I squat.”
“My wife can hear them from across the room.”
And underneath the description is almost always the same fear. That the noise is cartilage wearing away, that something is grinding itself down, and that every squat is using up a knee that cannot be replaced.
The research on this is clearer than most people expect, and considerably more reassuring.
Start With How Common It Is
A systematic review published in the British Journal of Sports Medicine looked at how prevalent knee crepitus actually is, crepitus being the clinical word for any grinding, creaking, cracking, grating, crunching or popping from a moving joint.
The findings:
Knee crepitus is present in 41 percent of the general population.
It is present in 36 percent of uninjured, pain free controls.
It is present in 81 percent of people with knee osteoarthritis, and in 35 to 61 percent of people with other knee conditions.
And an older study that examined 250 normal, pain free knees found that 99 percent had patellofemoral crepitus when properly assessed.
Read those numbers again. Noise from a knee is closer to a normal finding than an abnormal one. A large proportion of people with completely healthy, pain free knees have noisy ones.
Does It Mean Damage?
Here is where it gets interesting, because the honest answer has two halves and most articles only give you one.
The half that sounds concerning: the same systematic review found that the presence of knee crepitus was associated with more than three times the odds of a radiographic osteoarthritis diagnosis. So there is a genuine statistical association between noise and visible changes on imaging.
The half almost nobody mentions:
A study comparing 165 women with patellofemoral pain against 158 pain free women found a higher proportion of crepitus in the pain group, but crepitus showed no relationship with function or with other self reported clinical outcomes.
Research has also found that people with kneecap pain who have noisy knees have similar levels of pain, function, fear of movement and knee strength compared with people who have kneecap pain and quiet knees.
And a longitudinal study using data from the Osteoarthritis Initiative found that knee crepitus was not associated with going on to have a total knee replacement.
So the fair summary is this. Noise is associated with imaging changes. It is not associated with how much pain you have, how well your knee works, how strong it is, or how likely you are to need surgery.
Which means it is a poor guide to how your knee is actually doing.
Why the Belief Matters More Than the Noise
This is the part that genuinely affects outcomes.
Qualitative research into what people believe about knee crepitus has found that those beliefs affect exercise behavior and physical activity levels. People hear the noise, interpret it as damage accumulating, and reduce what they do in order to protect the joint.
A separate study of beliefs about knee osteoarthritis found that patients overwhelmingly held structurally focused views, fixated on concepts like wear and tear, bone on bone, and missing cartilage, and that this promoted inactivity out of fear of making things worse.
Here is the problem with that. Inactivity appears to be a greater risk factor for worsening pain and disability in osteoarthritis than the activity people are avoiding.
So the belief causes the behavior, the behavior causes the deconditioning, and the deconditioning causes the outcome everyone was trying to avoid.
The noise did not do that. The interpretation of the noise did.
Where the Fear Comes From
Partly from the internet, and partly from language used in clinical settings.
One editorial on this topic noted that many websites fail to distinguish between the unusual, coarse crepitus associated with advanced arthritic change and the common, fine crepitus that most people have, leading people to wrongly self diagnose severe degenerative disease.
And phrases matter. Being told your knees are bone on bone, or worn out, or shot, changes how people move for years afterward. Those descriptions are frequently delivered casually and land permanently.
What Should Actually Concern You
None of this means ignore your knee. It means the noise is the wrong thing to measure. These are the right things:
Pain. Is it painful, and is that changing over weeks?
Function. Can you do what you want to do? Stairs, squatting, hiking, getting off the floor?
Swelling. A knee that swells is telling you something. A knee that clicks is not.
Giving way. A knee that buckles or feels unreliable needs assessing.
Locking. A knee that catches and will not fully straighten needs assessing.
And strength. How does it compare to the other side?
A simple rule: if the noise comes with pain, swelling, giving way or locking, get it looked at. If it is noise alone, the evidence suggests it is unlikely to be meaningful.
What To Do About It
Keep using the knee. This is the main message. Given what the evidence says about inactivity, protecting a noisy knee from load is more likely to cause problems than the load was.
Build strength. Quadriceps and hip strength are the things that genuinely influence how a knee feels and functions over time. Sit to stands, step ups, squats to a comfortable depth, progressed over weeks and months.
Load it progressively rather than avoiding it. Discomfort during exercise up to a moderate level is generally acceptable. The test that matters is the next morning. Back to your usual baseline means the load was fine. Clearly worse means reduce it by around 20 to 30 percent and build back more gradually.
And stop listening for it. Monitoring a symptom increases how much you notice it. People who become attentive to their knee noise hear it constantly, and that attention has its own effect.
When to Get It Checked
Seek prompt assessment for a knee that locks or will not fully straighten, a knee that gives way repeatedly, significant swelling, particularly if it came on within a few hours of an injury, inability to bear weight, or pain following a specific injury with a pop.
Seek same day medical care for a knee that is hot, red and swollen, especially with fever.
And book an assessment if you have knee pain that is persisting beyond a few weeks, worsening over time, limiting activities you want to do, or if you have simply started avoiding things because of it.
The Short Version
Noise in a knee is extremely common, it occurs in the large majority of pain free knees, and it has not been shown to predict pain, function, strength or future surgery.
What does predict those things is strength, activity and what you believe about your joint.
If your knee is noisy and nothing else, it is probably fine. If your knee is noisy and painful, it is the pain that needs addressing.
Let Us Take A Look
If you have been avoiding squats, stairs or hikes because of the noise your knees make, that is worth sorting out, and the answer is usually considerably more encouraging than people expect.
Highland Physical Therapy offers a Free Discovery Visit at no cost and no obligation. You will get a thorough assessment of your knee, your strength and your movement here in Pocatello, an honest explanation of what is actually going on, and a plan to get you back to the activities you have been protecting yourself from.
Request your Free Discovery Visit today. Or call us on 208-237-2080.
