How long does a knee replacement last?
Most knee replacements last a long time. Pooled data from national registries show that about 93% of total knee replacements are still in place at fifteen years. Australian registry data agree, and extend the picture further: around 95% are still in place at ten years, about 94% at fifteen years, and about 92% at twenty years. For most people, a knee replacement is a once-in-a-lifetime operation.
What those numbers mean
Those figures are the share of knee replacements still in place, not yet needing a further operation. Your own chance of ever needing a second one also depends on your age. The older you are when you have it, the more likely the joint simply lasts for the rest of your life. A younger, more active person puts more years and more load through the joint, so the lifetime chance of needing a revision is higher. None of these are predictions for any one knee; they describe large groups, and individual results vary.
Why knee replacements eventually wear out
A knee replacement is durable, but not immortal. When one does eventually need redoing, Australian registry data show the most common reasons are loosening of the implant from the bone, infection, and the joint becoming unstable, with ongoing pain or kneecap problems accounting for many of the rest.² Wear of the plastic spacer, once a common cause, is now much less frequent with modern implants.²
What affects how long yours lasts
- Your age at surgery, as above.
- Your weight. More body weight means more load through the joint with every step, which can mean more wear over time.
- Activity. A knee replacement handles walking, swimming and cycling well. High-impact activities like running and jumping put more strain on it and are generally not recommended.
- The implant and how it's placed. Modern implants are durable, and accurate positioning matters. Newer approaches such as functional alignment and robotic assistance aim to position the implant to suit your knee; whether they make replacements last longer is still being studied.
Partial knee replacements
A partial (unicompartmental) knee replacement, which resurfaces only one part of the knee, has a higher revision rate than a total knee replacement, roughly double in registry data.² When a partial knee does need revising, it's usually converted to a total knee replacement, which generally works well. For the right patient the trade-off can still be worthwhile. Dr Tsung will advise which suits your knee.
Helping it last
You can't control everything, but a few things help: keeping to a healthy weight, staying active while avoiding high-impact strain, and seeing your surgeon if the knee becomes newly painful, swollen or unstable rather than waiting. There's no need for routine check-ups if all is well, unless your surgeon suggests otherwise.
If a knee replacement does wear out
If a replacement loosens or wears out, it can be revised: the old components are removed and new ones fitted. Revision surgery is a bigger operation than the first replacement and can be more complex, but for most people it restores comfort and function. Knowing this is the safety net behind the long-term numbers.
Common questions
Will I need a second knee replacement?
Most people don't. Around 95% of knee replacements are still in place at ten years, about 94% at fifteen years, and about 92% at twenty years.¹,² The chance is higher if you're younger at the time of surgery.
Can I run or play sport afterward?
Low-impact activity such as walking, swimming, cycling and golf is encouraged. High-impact activity like running and jumping is generally discouraged because it adds wear. Your surgeon will advise on your situation.
How will I know if it's wearing out?
New or increasing pain, swelling, or a feeling of instability are worth getting checked. Wear is often silent early on, which is why new symptoms shouldn't be ignored.
Speak to Dr Tsung
To discuss knee replacement, you'll need a referral from your GP or another specialist. Call reception on (07) 5676 9930 to book your first appointment, or email hello@sgco.au. New patients can pre-register online before the visit; the form prepares your records and does not book an appointment. More on knee replacement.
References
- Evans JT, Walker RW, Evans JP, Blom AW, Sayers A, Whitehouse MR. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393(10172):655–663.
- Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). Hip, Knee & Shoulder Arthroplasty: 2025 Annual Report. Adelaide: AOA; 2025.