A knee replacement is a type of surgery that takes out the damaged knee joint and replaces it with parts made of metal, plastic, or ceramic. You should have less pain and more movement in your knee after surgery.
There are 3 types of knee replacement surgeries:
- Total knee replacement: The entire knee joint is taken out and replaced with new parts.
- Partial knee replacement: Only the most diseased or damaged part of the knee is taken out and replaced with new parts.
- Knee revision: The parts used to replace the knee have become damaged or loose and have to be taken out and replaced with new ones.
The type of surgery you need and the parts you get depend on:
- the condition of your knee
- your age
- your weight
- the activities you like to do
Your surgeon will speak with you about what is best for you.
Below are 2 images of what a total knee replacement might look like from the inside. This surgery used metal and plastic parts.
Front view after a knee replacement
Side view after a knee replacement 
Credit: All images on this page belong to the Bone and Joint Health Strategic Clinical Network, Alberta Health Services.
Why do I need a knee replacement?
You may need a knee replacement because the cartilage (or cushioning) between the bones in your knee has worn away. This causes the bones to rub against each other, which causes pain and stiffness in your knee.
There are a few reasons your healthcare team may suggest a knee replacement:
- Pain keeps you awake at night.
- Pain and stiffness in your knee causes you to cut back or stop your normal, everyday activities.
- You’ve tried other treatments (like exercise and medicine), and they didn’t help.
Does the surgery have risks?
Knee replacement surgery is usually safe, but there are some risks. Your surgeon and healthcare team will talk to you about the risks.
Infection
Germs can enter your body from anywhere, such as your teeth, skin, or throat. Germs can cause an infection. Certain health problems (like diabetes) and lifestyle choices (like smoking or not eating well) can put you at higher risk of an infection from surgery. You may get antibiotics before and after surgery to prevent infection.
Tell your surgeon or case manager if you have or think you have an infection.
Blood clots
A blood clot is a clump of blood that forms in a blood vessel. It can be very serious if it moves to your lungs. You’ll get a blood thinner to help prevent a blood clot. It’s also important to get up and move around as soon as possible after surgery to help prevent a blood clot.
Tell your surgeon or case manager if you’ve ever had a blood clot.
Heart attack, lung problems, stroke, allergic reactions
The risks of any surgery include heart attack, breathing or lung problems, a stroke, and an allergic reaction (to medicines used during surgery). Death is also a very rare risk of surgery.
You and your healthcare team will work together to lower these risks and make sure the surgery is as safe as possible for you.
A break in the bone around your new joint
You could have a break in the bone around your new knee joint. If this happens, you may need to put less weight on the leg or have another surgery.
Nerve damage, bleeding, or injury to a blood vessel
You may notice a loss of feeling or movement after surgery. Tell your healthcare team if you notice any changes.
Knee stiffness
Your knee may be very stiff after surgery. It’s important to do your exercises to prevent this. You may need another surgery to improve how well you can bend your knee if it stays stiff.
The new knee parts become loose
Your new knee joint may become loose over time. It’s important to go to all your follow-up clinic visits after surgery. Tell your doctor if you have any new pain in your knee. You may need surgery again if your knee joint gets too loose.
