Ceramic

Ceramics are crystalline structures either based on Alumina and sometimes Zirconia and sometimes composite materials.  They are extremely hard and wear resistant.  They are also quite critical in terms of manufacturing and the potential downside of ceramic is that they are quite sensitive to crack propagation and very rarely fracture.  However, having said that the risks of fracture in most well designed ceramic bearings are very low but there have been occasions where fractures have occurred.

Ceramic can be used against a high density polyethylene or cross link polyethylene or it can be used articulating on a ceramic counterpart on the acetabulum.  More recently the combination of ceramic articulating with a metal acetabular component has been looked at in the hip.

Theoretically, experimentally and clinically the ceramic on ceramic bearing probably produces the least wear of any articulation and the ceramic debris is very inert in the body and therefore has been used more recently and more frequently, particularly in the UK.  The slight downside to ceramic is a very low fracture risk in the region of 1 in 10,000 or so and a small incidence of squeaking that can occur with a ceramic on ceramic articulation.  Ceramics articulating on ceramic have been used for many years on the continent and very good results have been obtained at 10, 15 years.  Newer types of ceramics such as Delta ceramic have yet to be fully assessed but theoretically may be better materials.