B Masson (Toulouse)
Ceramic components and ceramic-on-ceramic bearings have been applied successfully for more than 40 years in several millions of total hip arthroplasty (THA) implants. In the first decades pure alumina ceramics were the material of choice due to the high hardness, wear resistance and biocompatibility.However the call for stronger and tougher material led to the development of alumina matrix composites (AMC) that incorporated sub-micron alumina and zirconia particles. This latest generation of zirconia platelet toughened aluminates (ZPTA) with the trade name BIOLOX® delta for more than 15 years in clinical use and with more than 7 million hip components delivered, has demonstrated its proposed advantages for primary THA over other bearing options which is also confirmed by arthroplasty registries.
This has been underlined by several in-vitro studies showing:
(a) the lowest wear of all materials, even in off-normal conditions due to high scratch resistant articulating surface, (b) a lower friction torque both in hard-on-soft and hard-on-hard articulation combination, (c) to be safe in terms of ion release, (d) the mitigation of fretting corrosion, (e) the lower risk of revision for periprosthetic joint infection (f) the reduced biofilm formation and the higher fracture resistance.
Furthermore, there are no known pathogenic reactions to ceramic particles and no known risk of allergy demonstrating the bioinertness of the material even in clinical setting.
The described material has been used successfully in total knee replacement. Future developments suggest not only the use of the dense structural material for other joint replacement applications but also the use of porous modifications that allow bone-ingrowth into the open pore structure. Hybrid components with dense load bearing structure and
open pore scaffolding can combine the advantages of different material species and can facilitate new applications which are not possible with current material.