Press-fit stability of uncemented hemispheric acetabular components: a comparison of three porous coating systems.

Cementless acetabular components require good initial fixation to allow bony in-growth. The initial press-fit stability, important for designs that do not rely on supplemental fixation, was examined for three designs with different porous coating systems: beads, fiber mesh, and plasma spray. The ability to withstand tangential loads was determined (maximum rim loads: 122-1730 N). The plasma-sprayed acetabular cups withstood the greatest tangential load within the specified range of motion of 150 microm (P<0.01). Differences in surface preparation of titanium acetabular cups may significantly affect the initial stability of the implants in rim loading.