Knee replacement surgery (arthroplasty) is a routine operation that involves replacing a damaged, worn or diseased knee with an artificial joint.
Adults of any age can be considered for a knee replacement, although most are carried out on people between the ages of 60 and 80. More people are now receiving this operation at a younger age.
A replacement knee usually lasts over 20 years, especially if the new knee is cared for properly and not put under too much strain.
Knee replacement surgery is usually necessary when the knee joint is worn or damaged to the extent that your mobility is reduced and you experience pain even while resting.
The most common reason for knee replacement surgery is osteoarthritis. Other conditions that cause knee damage include:
You may be offered knee replacement surgery if:
You'll also need to be well enough to cope with both a major operation and the rehabilitation afterwards.
There are two main types of surgery, depending on the condition of the knee:
Read more about how knee replacement surgery is performed.
There are alternative surgeries to knee replacement, but results are often not as good in the long term. Your doctor will discuss the best treatment option with you. Alternatives may include:
Choose a specialist who performs knee replacement regularly and can discuss their results with you.
This is even more important if you're having a second or subsequent knee replacement (revision knee replacement), which is more difficult to perform.
Your local hospital trust website will show which specialists in your area do knee replacement. Your GP may also have a recommendation, or arrange for you to follow an enhanced recovery programme.
You can also read a guide to NHS waiting times.
Before you go into hospital, find out as much as you can about what's involved in your operation. Your hospital should provide written information or videos.
Stay as active as you can. Strengthening the muscles around your knee will aid your recovery. If you can, continue to take gentle exercise, such as walking and swimming, in the weeks and months before your operation. You can be referred to a physiotherapist, who will give you helpful exercises.
Read about preparing for surgery, including information on travel arrangements, what to bring with you and attending a pre-operative assessment.
You'll usually be in hospital for three to five days, but recovery times can vary depending on the individual and type of surgery being carried out.
Once you're able to be discharged, your hospital will give you advice about looking after your knee at home. You'll need to use a frame or crutches at first and a physiotherapist will teach you exercises to help strengthen your knee.
Most people can stop using walking aids around six weeks after surgery, and start driving after about eight to 12 weeks.
Full recovery can take up to two years as scar tissue heals and your muscles are restored by exercise. A very small amount of people will continue to experience some pain after two years.
Read about recovering from knee replacement surgery.
Knee replacement surgery is a common operation and most people don't experience complications. However, as with any operation, there are risks as well as benefits.
Complications are rare but can include:
In some cases, the new knee joint may not be completely stable and further surgery may be needed to correct it.
Read more about the risks of knee replacement surgery.