People usually have knee replacement surgery because their joints have been damaged by arthritis. Knee replacement means replacing the surfaces of the bones that make up your knee joint. Your surgeon removes the old knee joint and puts in a new joint. The incision is closed and a large bandage is wrapped around your knee.
Like a normal knee, your new knee joint will have smooth weight-bearing surfaces that will allow you to walk more easily.
There are two types of knee replacements:
Total knee replacement
Total knee replacement is a surgical procedure where the worn, diseased, or damaged surfaces of a knee joint are removed and replaced with artificial surfaces. The clinical term for this surgery is “arthroplasty.” All the damaged bone and cartilage on the thigh bone (femur) and the lower leg shin bone (tibia) are replaced. Sometimes the patella (kneecap) may be resurfaced as well.
Hemiarthroplast
Some people only need part of the knee joint replaced. If only one side of the thigh bone (femur) and lower leg shin bone (tibia) is damaged your surgeon may do a hemiarthroplasty.
Your surgeon will tell you what type of knee replacement you need. The type of artificial knee that is best for you will depend on the condition of your knee and your health, as well as your height, weight, age and lifestyle.
What is my new knee made of?
Your new artificial knee joint (prosthesis) may be made of metal or ceramic, and plastic. These new parts make the knee joint smooth again, to stop pain and restore your joint movement.
How is my new knee attached?
There are different ways that the surgeon will attach your new knee. The surgeon may use cement, a non-cemented type of substance or a combination of these.
Cemented
The new (artificial) joint is attached to the existing bone with a special cement or glue.
Non-cemented
A special coating is used to help the existing bone to stick to the new (artificial) joint. Over time, the body produces new bone tissue that grows into the tiny spaces in the coating, allowing the joint to become firmly attached.
Hybrid
A combination of the two types is used. The end of your femur (thigh) bone is removed and replaced. The top end of your tibia (lower leg bone) is removed and replaced with a metal stem. It is covered with a special coating that helps the existing bone stick to the new (artificial) joint. Over time, the body produces new bone tissue that grows into the tiny spaces in the coating, allowing the joint to become firmly attached. In some cases, screws may be used to make it more stable.
The decision about whether to use cemented, non-cemented, or a combination of the two is usually made by the surgeon based on your age, the condition of your bones, and your lifestyle.
Why do I need a knee replacement?
Knee replacement surgery is needed when your pain becomes so severe that it interferes with your daily living and ability to simple activities such as walking, or climbing up and down stairs.
You may need to have a knee replacement to:
Replacing a painful, arthritic joint with an artificial joint will give your knee a new smooth surface that will allow you to move more freely, and stop your bones from rubbing against each other. The goal is to allow you to return to doing, and enjoying, your activities of your normal daily life.