Hydrothermal Stability of Ceramic Femoral Heads
Alumina ceramics have been used in total hip replacements for over 30 years with much success, although some in-vivo failures of early generation alumina ceramic heads were reported. This resulted in the introduction of zirconia (yttriastabilised tetragonal zirconia, Y-TZP) as a ceramic femoral head, with its improved strength and fracture toughness. Zirconia, however, is known to undergo hydrothermal degradation. This hydrothermal degradation is due to the phase transformation from the metastable tetragonal phase into the monoclinic phase. This transformation starts from the surface and progresses into the bulk with a volume increase of approximately 3–4 %. This increase in monoclinic phase content may result in surface roughening of the ceramic head and is linked to a reduction in strength and increased UHMWPE wear [1,5].
KeywordsArtificial Aging Average Surface Roughness Hydrothermal Stability Ceramic Head Burst Strength
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