Total knee replacement, also called
total knee arthroplasty, uses metal alloy and polyethylene (plastic)
components to resurface the bones in the joint. The implants are
designed to re-create the shape of the bones in a healthy joint.
The end of the thighbone can be compared to a rocking chair. It has two
distinct surfaces, or rockers, that contact the top of the shinbone.
Each rocker is called a condyle, and there are two condyles at the end
of the thighbone. The femoral component re-creates each rocker at the
end of the thighbone. The top of the tibia is covered with a metal tray
that is used to support the polyethylene plastic bearing. The
polyethylene acts as the joint's natural cartilage, absorbing stress and
providing smooth movement. The polyethylene on the back of the kneecap
also provides smooth movement against the femoral component.
