Knee replacement

When a knee replacement is needed

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:

• rheumatoid arthritis
• haemophilia
• gout
• disorders that cause unusual bone growth (bone dysplasias)
• death of bone in the knee joint following blood supply problems (avascular necrosis)
• knee injury
• knee deformity with pain and loss of cartilage

Who is offered knee replacement surgery

A knee replacement is major surgery, so is normally only recommended if other treatments, such as physiotherapy or steroid injections, haven't helped reduce pain or improve mobility.

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.

Preparing for knee replacement surgery

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.

Recovering from knee replacement surgery

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.

Risks of 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:

• stiffness of the knee
• infection of the wound
• deep infection of the joint replacement, needing further surgery 
• unexpected bleeding into the knee joint
• ligament, artery or nerve damage in the area around the knee joint
• blood clots or deep vein thrombosis (DVT)
• persistent pain the in the knee
• fracture – a break in the bone around the knee replacement during or after the operation

In some cases, the new knee joint may not be completely stable and further surgery may be needed to correct it.

The National Joint Registry

The National Joint Registry (NJR) collects details of knee replacements carried out in England and Wales. Although it's voluntary, it's worth registering. This enables the NJR to monitor knee replacements, so you can be identified if any problems emerge in the future.

The registry also gives you the chance to participate in a patient feedback survey.

It's confidential and you have a right under the Freedom of Information Act to see what details are kept about you.