A knee replacement resurfaces the damaged ends of the thigh and shin bones with metal and plastic parts. The NHS notes that it may be recommended when knee pain is having a big effect on your life and alternatives have not worked. Most people who have one have osteoarthritis; it is also used for other types of arthritis, including arthritis after injury.
Total and partial knee replacement
A total knee replacement is the most common type. Some people also have the back of the kneecap resurfaced, which NICE recommends offering. A partial knee replacement replaces only the affected part of the knee and is used when arthritis is confined to one side. NICE recommends offering a choice of partial or total replacement to people whose arthritis is isolated to the inner (medial) compartment, after discussing the benefits and risks of each.
The NHS notes that the operation usually takes about 1 to 2 hours, under either a general anaesthetic or a spinal anaesthetic.
Who it is for
The decision rests on how much the knee is limiting your life, whether non-operative treatment has helped, and your general health — not on an X-ray alone. See the knee arthritis guide for non-operative options.
How long knee replacements last
The NHS notes that most knee replacements last for about 25 years. The National Joint Registry’s 2026 annual report describes many total knee implant options with revision rates under 2% at ten years and under 4% at 15 years. I favour implants with long registry follow-up. For more detail, see how long do modern knee replacements last?
Recovery
- You will be helped to walk soon after surgery, using crutches or a frame at first
- The NHS notes that most people go home 1 to 4 days after the operation
- Stitches or clips are usually removed after about 10 days, with a follow-up at about 6 weeks
- The NHS advises waiting at least 6 weeks before driving after a total knee replacement, or 3 weeks after a partial
- Return to work is usually after about 6 to 12 weeks, depending on the job
- Full recovery can take several months or longer; recovery from a partial replacement is usually shorter
Risks
The NHS notes that most people have no complications. Possible risks include blood clots, wound or deeper joint infection, damage to nerves, blood vessels or ligaments, and ongoing problems such as stiffness, pain or instability. Physiotherapy and exercises may help with these. I discuss risks openly so you can weigh them against how the knee affects you now.
After surgery, seek urgent advice (your GP or NHS 111) for throbbing or cramping leg pain, a high temperature, oozing from the wound, or worsening redness, swelling or pain. Call 999 for breathlessness or chest pain.
Questions worth asking
- Is my arthritis in one part of the knee, and would a partial replacement be an option?
- Which implant would you use, and what does its registry record show?
- What anaesthetic and pain relief options are there?
- What will recovery look like for my work and activities?
The right choice depends on your history, examination and imaging. If you would like a clear assessment, you can arrange a private consultation or discuss a referral with your GP.
Frequently asked questions
What is the difference between a total and a partial knee replacement?
A total knee replacement resurfaces the whole joint. A partial knee replacement replaces only the affected side and is used when arthritis is confined to one part of the knee; recovery is usually shorter.
How long will I be in hospital?
The NHS notes that people usually leave hospital 1 to 4 days after the operation, once they can get around safely.
When can I drive after a knee replacement?
The NHS advises waiting at least 6 weeks after a total knee replacement or 3 weeks after a partial, and checking with your doctor that you are fit to drive.
How long does a knee replacement last?
The NHS notes that most knee replacements last for about 25 years.
References
- NHS. Why a knee replacement is done. https://www.nhs.uk/conditions/knee-replacement/why-its-done/
- NHS. How a knee replacement is done. https://www.nhs.uk/conditions/knee-replacement/how-its-done/
- NHS. Recovering from a knee replacement. https://www.nhs.uk/conditions/knee-replacement/recovery/
- NHS. Complications of a knee replacement. https://www.nhs.uk/conditions/knee-replacement/risks/
- NICE. Joint replacement (primary): hip, knee and shoulder (NG157), recommendations. National Institute for Health and Care Excellence, 2020. https://www.nice.org.uk/guidance/ng157/chapter/Recommendations
- National Joint Registry. 23rd Annual Report (2026): Executive Summary. https://reports.njrcentre.org.uk/AR-Executive-Summary