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Clicking after knee replacement: is it normal?
If your knee replacement clicks, clunks, or pops: you are not alone. Published guidance from the AAOS indicates that noticeable sounds from a knee replacement are very common and usually harmless. Here is what the evidence says about why it happens and when it matters.
⚕️ General information only: not medical advice. If clicking is accompanied by pain, swelling, or instability, contact your surgical team. This guide cannot diagnose your symptoms.
The short answer
Published guidance from the AAOS indicates that clicking and clunking sounds after knee replacement are reported by up to 18% of patients and are usually completely normal. A knee replacement is a mechanical joint made of metal and plastic. It does not feel or sound exactly like a natural knee. Painless clicking that has been present since surgery and is not worsening is almost always benign. (Last checked Jul 2026)
What causes clicking sounds?
Published guidance identifies several common causes of sounds after knee replacement. (AAOS, NHS, last checked Jul 2026)
- Crepitus: The most common cause. The polyethylene (plastic) bearing surface moves against the metal femoral component, producing a clicking or grinding sensation. This is a normal characteristic of the prosthesis and is not a sign of wear
- Soft tissue snapping: Tendons, the IT band, or scar tissue can glide or snap over the implant components as the knee bends and straightens. This often improves as swelling reduces and tissues settle around the implant
- Patella tracking: The kneecap (patella) moves over the front of the implant during bending. If the kneecap tracking is slightly altered from surgery, it can produce a click or clunk, particularly when going up or down stairs
- Gas bubble release: Similar to knuckle cracking, dissolved gas in the joint fluid can form small bubbles that pop when the joint moves through certain ranges. This is harmless
- Component design: Some implant designs have features (such as a posterior-stabilised cam mechanism) that are designed to produce a subtle clunk at a specific point in the range of motion. This is expected and normal for that design
Normal clicking vs concerning clicking
Usually normal
- ✓ Painless clicking or popping
- ✓ Present since early recovery
- ✓ Consistent (not getting worse)
- ✓ No swelling or warmth
- ✓ Knee feels stable
- ✓ Worse when cold, better when warm
Contact your surgeon
- ⚠ Clicking with new or worsening pain
- ⚠ New clicking that was not there before
- ⚠ Loud clunk with every step
- ⚠ Knee feels unstable or gives way
- ⚠ Knee locks or gets stuck
- ⚠ Swelling, warmth, or redness
Source: Published orthopaedic guidance (AAOS, NHS, last checked Jul 2026). If you are unsure, bring it up at your next appointment — your surgeon can assess whether investigation is needed.
Why clicking causes so much anxiety
It is completely understandable to feel worried when your new knee makes unexpected sounds. Many patients report that clicking causes more anxiety than the clicking itself warrants. Here is what is worth knowing:
- Your natural knee was also not silent, but you were used to its sounds. A new joint produces different sounds, and because you are paying close attention during recovery, you notice every one of them
- Published guidance confirms that the vast majority of knee replacement clicking is benign. Surgeons hear about it frequently and are rarely concerned by painless clicking
- Clicking often becomes less noticeable over time: not necessarily because it stops, but because your brain habituates to the sounds as the joint becomes "yours"
- If clicking is causing you significant worry, raise it with your surgeon. A brief examination and sometimes an X-ray can provide reassurance that everything is positioned correctly
⚠️ When clicking needs urgent review
- Clicking with progressive pain that is worsening over weeks or months (possible implant loosening)
- Knee gives way or feels unstable during walking (possible ligament or component issue)
- Knee locks in one position and cannot be straightened or bent (possible mechanical block)
- New swelling with warmth and redness (possible infection)
- Sudden loud clunk after a fall or twisting injury
In an emergency, call 000 (AU) · 999 (UK) · 911 (US) · 112 (EU)
Common questions
Does clicking mean my knee replacement is loose?
Published guidance from the AAOS indicates that painless clicking alone does not indicate a loose implant. Implant loosening typically presents with progressive weight-bearing pain that worsens over months: not clicking. If you have both clicking and increasing pain, your surgeon can investigate with X-rays. Clicking without pain is rarely a sign of loosening. (Last checked Jul 2026)
Will the clicking go away?
Published guidance indicates that some clicking improves as swelling resolves and muscles strengthen — typically over 6 to 12 months. Some patients have mild clicking permanently, which is a normal characteristic of the prosthetic joint. The key marker is whether clicking is painless and stable (not getting worse).
Can other people hear my knee clicking?
In most cases, the sounds are felt more than heard and are only noticeable to the patient. Some patients do experience louder clicks that others can hear, particularly on stairs or when standing from sitting. Published guidance indicates that audible clicking is not in itself concerning, but if it is new and was not present before, mention it at your next review.
Is clicking worse on stairs?
Yes, this is very common. Stair climbing involves deep knee bending under load, which brings the implant components through a wider range of motion and increases the chance of audible clicking. Published guidance indicates that stair-related clicking is typically caused by the patella tracking over the implant and is usually normal. (AAOS, last checked Jul 2026)
Should I stop exercising if my knee clicks?
Published guidance indicates that painless clicking during exercise is not a reason to stop. Exercises and physiotherapy remain important for recovery. If clicking is accompanied by pain during specific movements, mention those movements to your physiotherapist, they may adjust your programme, but stopping altogether is generally not necessary.
Related guides
Managing your new knee
Clicking is usually harmless, but keeping the joint moving well makes all the difference.
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Cold therapy after exercises helps manage any swelling that flares up, especially useful in the early months when clicking tends to be most noticeable. Cold therapy wrap →
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Gentle resistance work strengthens the muscles around the implant, which often reduces clicking over time as the joint stabilises. Resistance bands →
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Keeping the skin and scar supple with regular massage can help the tissues settle around the new joint. Silicone scar sheets →
Postopcare.info may earn a small commission from Amazon at no cost to you. These are things patients have told us genuinely helped their recovery: nothing else.
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