16. Orthopaedic Polymers

The Mainstream twins’ friend Pearl had an arthritic knee that had been treated by implant arthroplasty, and she was doing very well indeed. She was able to do virtually anything she wished, but in recent months she had begun to have pain in the knee. Because the discomfort limited her walking ability, she made an appointment to see her surgeon, who told her she needed a revision operation. When the surgeon opened the knee, he found the femoral component intact but the plastic on the tibial side badly worn. These modern plastic components should last forever, should they not? What happened to this one?