The objective of this study was to evaluate biomechanically and histologically the effectiveness of different surfaces—specifically, smooth, textured, and plasma-sprayed porous surfaces—on titanium implants in achieving stable fixation for total joint replacements.
Hollow cylindrical metal plugs (5 to 6 mm in diameter) with different surfaces were implanted in the femora of two dogs. After five months of implantation, pull-out tests were carried out on these cylinders. The ultimate shear strengths were 11.54 ± 2.96, 3.17 ± 0.81, and 1.04 ± 0.32 N/m2 for the plasma-sprayed, textured, and smooth surfaces, respectively. As expected, the smooth cylinders showed the minimum pull-out strengths and the porous-coated ones the maximum. Histological examination showed maximum bony ingrowth in the plasma-sprayed group and moderate growth in the textured group. Our results suggest that a textured surface or a porous coating (plasma spray) on titanium implants could significantly improve the long-term stability of uncemented total joint replacements.