Artificial joint components

Most artificial joints in use today incorporate a metal or ceramic head against an ultra-high molecular weight polyethylene (UHMWPE) cup. The use of ceramic components in joint replacement surgery was initiated in the 1970s with the introduction of first generation alumina products, when ceramic's superior resistance to wear in comparison to more traditional metal and polyethylene materials became apparent. Advances in material quality and processing techniques and a better understanding of ceramic design led to the introduction of second generation alumina components in the 1980s that offered even better performance than early systems. Low system wear rate leads to long life-times, typically 20 years plus for ceramic, and in particular less polyethylene particulate debris generation which is a known cause of osteolysis and a major source of revision operations that are both costly and add trauma to patients. For example, a study on the performance of Morgan Technical Ceramics' HIP Vitox® ceramic on ceramic hip joints performance which reported recently quoted a wear rate of just 0.032mm3/million cycles*. Ceramic systems also alleviate recent concerns that have been raised over metal ion release from the use of metal implants in the body and their possible side effects. More recently, 'ceramic-on-ceramic' systems have been developed to eliminate the problems associated with polyethylene and metal altogether. Such systems have by far the lowest wear rate of all available bearing couple technologies available today. These systems have grown in popularity in Europe over the past five years or so and a milestone was reached last year (2003) when the Federal Drugs Agency (FDA) gave their clearance for use in the USA. Because of the better wear properties of ceramic-on-ceramic, such systems are ideally suited for the younger and more active patients. The international golfer Jack Nicklaus famously has a replacement ceramic hip.