This page will give you information about a unicompartmental knee replacement. If you have any questions, you should ask your GP or other relevant health professional.
You can also download and print a PDF version of this factsheet, with space for your own questions or notes.
What is arthritis?
Arthritis is a group of conditions that cause damage to one or more joints.
The most common type of arthritis is osteoarthritis, where there is gradual wear and tear of a joint. Arthritis eventually wears away the normal cartilage covering the surface of the joint and the bone underneath becomes damaged. This causes pain and stiffness in the joint.
If only part of your knee is damaged by arthritis, you can sometimes have a unicompartmental knee replacement instead of a total knee replacement.
What are the benefits of surgery?
You should get less pain and be able to walk more easily. A unicompartmental knee replacement may bend better and feel more like a normal knee than a total knee replacement.
Are there any alternatives to a knee replacement?
Simple painkillers such as paracetamol and anti-inflammatory painkillers such as ibuprofen can help control the pain. Supplements to your diet may also help relieve your symptoms. Check with your doctor before you take supplements.
Using a walking stick can make walking easier.
Regular moderate exercise can help to reduce stiffness in your knee. Physiotherapy may help to strengthen weak muscles.
A steroid injection into your knee joint can sometimes reduce pain and stiffness for several months.
An operation called a tibial osteotomy changes the shape of your leg and can take the load off the worn part of your knee.
All these measures become less effective if your arthritis gets worse.
What does the operation involve?
Various anaesthetic techniques are possible. The operation usually takes an hour to 90 minutes.
Your surgeon will make a cut on the front of your knee and remove the damaged joint surfaces. They will replace these with an artificial knee joint made of metal, plastic or ceramic, or a combination of these materials.
Your knee replacement is fixed to the bone using acrylic cement or special coatings on your knee replacement that bond directly to the bone.
What complications can happen?
- infection of the surgical site (wound)
- unsightly scarring
- blood clots
- difficulty passing urine
- chest infection
- heart attack
- damage to nerves
- damage to blood vessels
- bearing dislocation
- infection in your knee
- severe pain, stiffness and loss of use of your knee (complex regional pain syndrome)
How soon will I recover?
You should be able to go home after 1 to 4 days. You will need to use crutches or walking sticks for a few weeks.
Regular exercise should help you to return to normal activities as soon as possible. Before you start exercising, ask the healthcare team or your GP for advice.
Most people make a good recovery, have less pain, and can move about better. An artificial knee never feels quite the same as a normal knee.
A unicompartmental knee replacement can wear out with time.
Arthritis of your knee usually happens without a known cause. It can sometimes affect only part of your knee. If you have severe pain, stiffness and disability, a unicompartmental knee replacement should reduce your pain and help you to walk more easily.
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Last reviewed: September 2018