Ceramic-on-ceramic bearings have the advantage of low wear and high biocompatibility. Alumina-ceramic particles are essentially insoluble in organic media and ionisation is therefore unimportant. However, they have some limits: brittleness is a major concern for ceramic, which could lead to clinically relevant failure rates (0.004% head fracture and 0.22% liner fracture. Although Metal-on-metal (MOM) articulations have been seen as one potential solution to the problems associated with UHMWPE-induced osteolysis, metal ions present in the serum and their potential toxic effects both locally and systemically are a cause for concern.