Knee replacement surgery, or knee arthroplasty, is an operation to remove damaged parts of your knee joint and replace them with artificial ones. It involves major surgery, but the improvements in knee pain and stiffness it gives can really improve your quality of life.

Why do I need a knee replacement?
How to get a knee replacement
Preparing for knee replacement
What happens during knee replacement surgery?
Recovery and what to expect after knee replacement
Complications of knee replacement
Knee replacement costs and fees
Helpful websites

Why do I need a knee replacement?

You may need a knee replacement if you have severe pain or loss of function of your knee, most commonly due to osteoarthritis. Your doctor may also recommend knee replacement surgery if your knee has been damaged due to other reasons – such as rheumatoid arthritis or injury.

Your doctor will only recommend knee replacement surgery when your symptoms are really interfering with your quality of life and other measures, such as exercise, physiotherapy and painkillers aren’t giving you enough pain relief.

How to get a knee replacement

You can have a knee replacement privately or on the NHS. Either way, you will need to see an orthopaedic surgeon to discuss whether surgery is suitable for you. Usually your own doctor will refer you. Waiting times for knee replacement in the NHS will vary depending where you live. But it can often take several months, especially with current delays due to COVID. The surgery is the same, whether it’s in the NHS or the private sector. But you may well have surgery sooner if you opt to have it done privately.

Preparing for knee replacement

Your surgeon will discuss the surgery with you and go through the benefits and risks of the procedure, and any potential alternatives. If you decide to go ahead, you’ll need an examination and several tests to check you’re well enough for knee replacement.

Your surgeon will advise you on things you should do before surgery, to make sure you’re in the best possible health beforehand. These may include:

  • exercises you can do to strengthen your leg muscles
  • stopping smoking
  • losing weight if you need to
  • getting any other health problems under control – like diabetes or high blood pressure

You’ll usually have a knee replacement under spinal or epidural anaesthesia, which means you’ll be numb from the waist down. You’ll be offered a sedative too, so you won’t be aware of the surgery being performed. Sometimes you may have a general anaesthetic. You’ll usually need to stay in hospital for a few days at least after your operation.

What happens during knee replacement surgery?

Knee replacement surgery involves making an incision over the front of your knee, and removing the damaged parts of bone inside your knee. These include the bottom of your thigh bone and top of your shin bone, and may include the underside of your kneecap too. Your surgeon then replaces these with artificial metal or plastic parts.

There are different types of knee replacement surgery.

  • Total knee replacement. This is when the bone surfaces on both sides of your knee are replaced. Sometimes the underside of your kneecap is replaced too.
  • Unicompartmental knee replacement (also called partial knee replacement or half knee replacement). This involves replacing damaged bone on just one side your knee. It’s a smaller operation and so recovery time is usually quicker.
  • Knee cap replacement. This means just replacing the underside of your knee cap – the ends of your thigh and shin bones don’t need replacing. This is only suitable for a few people with very localised osteoarthritis in this part of the knee.

Recovery and what to expect after knee replacement

Recovery after knee replacement can take time, but your healthcare team will help you to become mobile again as quickly as possible. The exact recovery time will depend on the type of surgery you’ve had, but it can take several weeks. You’re likely to have some pain and discomfort during this time. You’ll be given pain medication to help manage this.

Some people also have swelling for a while after surgery, particularly around their foot or ankle. It’s important to keep moving regularly and to avoid sitting still for too long. Your stitches or staples will normally be removed within a week or two. You’ll have a vertical scar from the surgery on the front of your knee, which should get paler with time.

You’ll see a physiotherapist after your operation, who can help to get you moving and start building up the strength in your knee. They’ll show you exercises to help with this. It’s important to build up your activities gradually after surgery, beginning with getting back to walking normally without pain. You’ll need crutches and walking sticks to help you walk at first. It can take around six to eight weeks to get back to walking without aids and other light activities like swimming. But you’ll need to avoid more strenuous activities and heavy lifting for longer.

You won’t be able to drive for a number of weeks after a knee replacement, so you’ll need to make arrangements for getting home.

Complications of knee replacement

All surgical procedures carry a risk of complications. Your risks can increase the older you are, particularly if you have other health problems. Your surgeon will discuss any specific concerns with you before your procedure.

Some of the more common complications of knee replacement include the following.

  • Infection. Your wound may become red, very painful or swollen, and you may notice some discharge or develop a fever.
  • Blood clots developing in your legs. This can cause pain and swelling.
  • Nerve injury. This can affect the movement and strength in your leg, and make your leg feel numb.
  • Ongoing pain or stiffness following your surgery.

Knee replacements are expected to last for many years. But the new joint can wear or loosen over time. You may then need further surgery.

Knee replacement costs and fees

Knee replacement is often available through private medical insurance. Check with your insurer whether they will cover it.

You can also self-fund a private knee replacement. Typically, an initial consultation with the surgeon will cost between £180 and £250. The cost of the procedure itself will vary depending on the exact surgery you need. Knee replacement costs in the UK also vary depending on where you live. If you move forwards with the procedure, you’ll be offered one of the following.

  • An all-inclusive ‘package price’, where you know the full costs before undergoing treatment. Not all consultants and hospitals offer this.
  • A ‘fee-per-service’ deal, where you pay for each part of your treatment and the services you use separately. You often won’t know the full costs until you receive invoices.

For more information, you can read our guide on self-pay.

Helpful websites


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  • Knee replacement surgery. Versus Arthritis. (accessed 14 July 2021).
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  • Rheumatoid arthritis in adults: management. National Institute for Health and Care Excellence (NICE),, last updated 12 October 2020.
  • Osteoarthritis: care and management. National Institute for Health and Care Excellence (NICE),, last updated 11 December 2020.
  • BOA statement on waiting times data release from January 2021. British Orthopaedic Association., 11 March 2021.
  • Joint replacement (primary): hip, knee and shoulder. National Institute for Health and Care Excellence (NICE),, published 4 June 2020.
  • Get well soon. Helping you to make a speedy recovery after a total knee replacement. Royal College of Surgeons of England. (accessed 15 July 2021).

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