Why does my knee click or crack? When noisy knees matter
Knees that click on the stairs, crack when you squat or make a grinding sound when you stand up are one of the most common things people worry about. Most of the time, a noisy knee that doesn't hurt is a normal knee.
Why does my knee click or crack?
There are several harmless explanations. Gas bubbles forming in the joint fluid cause an occasional single pop. Tendons and ligaments can flick over bony edges as the knee bends. The kneecap gliding in its groove can produce a fine grinding or crackling sensation, called crepitus. A review of knee noises emphasises that the key step is telling normal (physiological) noise from noise linked with a problem (Song et al., Clinics in Orthopedic Surgery, 2018).
Is a clicking knee a sign of arthritis?
Not by itself. Crepitus is common in people of all ages with healthy knees. In older adults, frequent crepitus is associated with a higher chance of later developing symptomatic knee osteoarthritis, particularly in people who already have arthritic changes on X-ray but no pain (Lo et al., Arthritis Care & Research, 2018). So in middle age and beyond, a persistently grinding knee is a reason to look after it, not a reason to stop using it.
Does the noise mean damage is being done?
No. The sound isn't bone grinding on bone, and bending a noisy knee doesn't wear it out. A study of women with and without kneecap pain found crepitus had no relationship with function, physical activity level or pain severity (de Oliveira Silva et al., Physical Therapy in Sport, 2018). How the knee feels and works matters far more than how it sounds.
When is a clicking knee a problem?
When the noise comes with other symptoms: pain, swelling, the knee catching or locking so it won't fully bend or straighten, the knee giving way, or a new click that started after a twisting injury. A painful clunk after an injury can indicate a meniscus tear.
See our post on meniscus irritation.
Why does my knee crack when I squat?
Squatting moves the kneecap through its full range under load, which is when crepitus is most noticeable. If it's painless, it's fine to keep squatting. If the front of the knee aches during or after, the area behind the kneecap may be irritated, which usually responds to adjusting load and strengthening.
See our post on knee pain when squatting.
Why does my knee click when I walk or climb stairs?
Stairs load the kneecap joint more than walking on the flat, so clicking and grinding are often noticed there first. Again, without pain or swelling it's usually harmless.
Should I stop exercising if my knees are noisy?
No. Avoiding activity because of noise tends to make knees weaker and less tolerant. Worry about knee noise can itself lead people to move less. Stay active, and judge by pain, swelling and function.
Can I make my knees less noisy?
Sometimes. Strengthening the thighs and hips can improve how the kneecap tracks, and some people notice less grinding as they get stronger. Often the noise persists regardless, and that's fine.
What exercises help?
Squats or sit-to-stands within a comfortable range, step-ups, leg press, bridges, side-lying hip work and calf raises. Start with a level that causes little or no pain and build gradually.
Do supplements help clicking knees?
There's no good evidence that glucosamine or similar supplements reduce knee noise or protect the joint.
See our post on joint supplements.
Why do my knees click after surgery or an injury?
New noises are common after knee surgery or an injury, partly because swelling and weakness change how the joint moves, and partly because you're paying closer attention. They often settle as strength returns. Painful catching or locking should be reviewed.
Do children's and teenagers' knees click?
Yes, commonly, especially during growth spurts. Painless clicking is normal. Pain at the front of the knee in an active child is worth assessing.
Is it bad to crack my knees on purpose?
An occasional deliberate pop isn't harmful, in the same way that knuckle cracking hasn't been linked with arthritis. There's no benefit in doing it repeatedly, and if you feel a constant need to, it's worth strengthening the area instead.
Does running make clicking knees worse?
Not if they're painless. Recreational running isn't associated with more knee arthritis, and regular loading helps keep joints healthy. Reduce your running only if the knee becomes painful or swollen.
How can an osteopath help?
We examine the knee to check that the joint, ligaments and meniscus are sound, explain where the noise is likely coming from, and, if there's pain, treat it and build a strengthening plan.
When should a knee be checked?
Book in for clicking with pain, swelling, catching, locking or giving way. See a doctor promptly for a knee that locks and won't straighten, swells quickly after an injury, or is hot and red.
See our knee and ankle pain guide. Book an assessment at our Berwick clinic. A 60-minute initial consultation is $149, with no referral needed and HICAPS on-site.
Sources
Song SJ, et al. Noise around the knee. Clinics in Orthopedic Surgery, 2018.
Book an initial consultation at RISE Sports & Spinal in Berwick. Clear diagnosis, hands-on treatment, and a plan that actually gets you better.
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