Fernández-Fairén M, Sala P, Gil F J
Policlínica Granollers, Granollers, Barcelona, Spain.
Biomed Mater Eng. 2006;16(6):415-22.
Fifty two ceramic femoral heads have been investigated after implantation. All heads had articulated against ultra high molecular weight polyethylene (UHMWPE) cups. Examination of the heads shows changes in sphericity and surface roughness due to the wear. The behaviour of these retrieved heads after clinical use confirms the problems derived from the use of yttria-stabilised tetragonal zirconia heads. In this paper, a failure mechanism for this type of ceramic is proposed. The slow yttria dissolution produces the transformation from tetragonal to monoclinic phase with a volume change. This fact provokes an important decrease in mechanical properties favouring wear. The yttria dissolution and the zirconia solid transformation were confirmed by X-ray diffraction.
52个陶瓷股骨头在植入后接受了研究。所有股骨头均与超高分子量聚乙烯（UHMWPE）杯进行了关节连接。对这些股骨头的检查显示，由于磨损，其球形度和表面粗糙度发生了变化。这些临床使用后回收的股骨头的情况证实了使用钇稳定四方氧化锆股骨头所产生的问题。本文提出了这种类型陶瓷的一种失效机制。钇的缓慢溶解导致四方相到单斜相的转变，并伴有体积变化。这一事实导致力学性能大幅下降，从而加剧磨损。通过X射线衍射证实了钇的溶解和氧化锆的固态转变。
