Mechanical stability of novel highly porous metal acetabular components in revision total hip arthroplasty.

Highly porous metal acetabular components have emerged for revision hip arthroplasty. However, superior mechanical stability over traditional cementless components has not been demonstrated. Three different cementless acetabular components, including 2 highly porous tantalum designs, were inserted into hemipelvis specimens with a superolateral defect. Mechanical testing was performed to failure using a servohydraulic testing machine. The porous tantalum designs exhibited superior stability over the traditional cementless implant (P < .05). There was no difference in mechanical stability between the rigid modular tantalum shell and the more flexible revision tantalum shell (P > .46). In acetabular revision, highly porous tantalum acetabular components provide superior mechanical stability. However, these results suggest that improved frictional resistance is a more important design feature over implant flexibility with this particular implant.