Generation of polyethylene wear debris from orthopedic prostheses is of major concern since it has been associated with osteolytic bone loss and, consequently, a reduction in joint lifetime. In large part due to this concern, metal/metal prostheses are being reconsidered for the articulating surfaces of hip and knee replacements. Wear of the metallic surfaces in this configuration is still of concern, particularly due to the questionable amount of lubrication available to the artificial joint. With the goal of minimizing wear and maximizing lifetime in metal/metal orthopedic systems, the proposed program will develop a unique metal matrix nanocrystalline composite surface. Such a material integrates the favorable wear characteristics of a ceramic with the inherent ductility, reliability, and adhesion of a metal. Metal matrix nanocrystalline composite surfaces will permit fabrication of more durable, reliable orthopedic prostheses with much longer effective lifetimes than conventional metal-on-polyethylene components.
More than 500,000 total and partial joint replacements are performed annually in the $1.8 billion U.S. orthopedic industry. Due to the link between polyethylene wear debris and osteolytic bone loss, alternatives to implants containing ultrahigh molecular weight polyethylene (UHMWPE) are being reconsidered, particularly in Europe. An orthopedic system that combines the benefits of ceramic and metal components and results in a wear rate that is two decades lower than with UHMWPE will be welcomed by manufacturers, surgeons, and patients.
