In vivo wear performance of highly cross-linked polyethylene vs. yttria stabilized zirconia and alumina stabilized zirconia at a mean seven-year follow-up

Table 2 Transformation rate and surface roughness of retrieved and unused zirconia heads

Cause of Revision	Zirconia Material	Duration (years)	Transformation rate (%)	Surface roughness Ra (μm)
Infection	PSZ	2.3	51	0.06
Dislocation	ASZ	1.5	7	0.03
Dislocation	ASZ	3.2	7	<0.01
Unused	PSZ		4	0.01
Unused	ASZ		3	<0.01

ISSN: 1471-2474