Environmental Stability and Residual Stresses in Zirconia Femoral Head for Total Hip Arthroplasty: In Vitro Aging versus Retrieval Studies

Figure 8

Monoclinic phase fractions on the surface of Head (I) are plotted as a function of in-vivo time simulated according to ISO (a) and ASTM criteria (b). Note that the comparisons of the transformation kinetics are made between in-vitro and in-vivo environment by coplotting the transformed contents on the surfaces of Heads (II) and (III) as well as monoclinic contents reported for Prozyr femoral head retrievals in [12–14].

(a) ISO simulation

(b) ASTM simulation