Hip New World

Abstract

This paper focuses on the development of modern metal-on-metal hips implants. Their large bearings mimic natural biomechanics and let patients remain active. Metal rubbing on metal creates nanoscale wear debris. The particles appear small enough for some cobalt and chrome to end up as ions. Both metals have the potential to cause cancer. Device manufacturers are scrambling after alloys that leave behind less debris. Some have also introduced ceramic hips. Ceramics are highly biocompatible and so hard and wear-resistant that they are likely to outlast metal. The ceramics used in hip implants are a triumph of materials science. The industry is moving toward zirconia-toughened alumina. It is stronger than conventional alumina and designers can slim down cup liners and use larger ceramic femoral bearings.