A total knee replacement is usually considered when the surfaces on both sides of the bones, as well as the underside of the patella, are significantly damaged.
In total knee replacement surgery, the surface of the thighbone (femur) is replaced with a contoured metal component designed to fit the curve of your bone. The surface of the shinbone (tibia) is typically replaced with a flat metal component and a smooth plastic component that serves as cartilage. The undersurface of the kneecap may also be replaced with an implant made of plastic, or a combination of metal and plastic.
The US National Institutes of Health (NIH) study concluded that total knee replacement is extremely successful, resulting in "rapid and substantial improvement in the patient's pain, functional status, and overall health-related quality of life in about 90% of patients."1 Globally, hundreds of thousands of knee replacement procedures are performed each year.