Abnormal Knee Knee with Replacement Implant The Knee Replacement Procedure When osteoarthritis develops in at least two of the three compartments in the knee, your doctor may recommend total knee replacement surgery. This procedure resurfaces the bone at the bottom of the femur (thighbone) and top of the tibia (shinbone). The implants are made from metal alloy and a form of plastic called polyethylene, and they replace only the damaged bone in the knee. The implants are designed to restore a more normal function and to reduce or eliminate pain in joints previously affected by arthritis. 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. Content provided by Orthopaedic Avenue a site published by Biomet, Inc.