The removal of Al2O3 particles from grit-blasted titanium implant surfaces: Effects on biocompatibility, osseointegration and interface strength in vivo

For the improvement of surface roughness and mechanical interlocking with bone, titanium prostheses are grit-blasted with Al2O3 particles during manufacturing. Dislocated Al2O3 particles are a leading cause of third-body abrasive wear in the articulation of endoprosthetic implants, resulting in inflammation, pain and ultimately aseptic loosening and implant failure. In the present study, a new treatment for the removal of residual Al2O3 particles from grit-blasted, cementless titanium endoprosthetic devices was investigated in a rabbit model. The cleansing process reduces residual Al2O3 particles on titanium surfaces by up to 96%. The biocompatibility of the implants secondary to treatment was examined histologically, the bone-implant contact area was quantified histomorphometrically, and interface strength was evaluated with a biomechanical push-out test. Conventional grit-blasted implants served as control. In histological and SEM analysis, the Al2O3-free implant surfaces demonstrated uncompromised biocompatibility. Histomorphometrically, Al2O3-free implants exhibited a significantly increased bone-implant contact area (p = 0.016) over conventional implants between both evaluation points. In push-out testing, treated Al2O3-free implants yielded less shear resistance than conventional implants at both evaluation points (p = 0.018). In conclusion, the new surface treatment effectively removes Al2O3 from implant surfaces. The treated implants demonstrated uncompromised biocompatibility and bone apposition in vivo. Clinically, Al2O3-free titanium prostheses could lead to less mechanical wear of the articulating surfaces and ultimately result in less aseptic loosening and longer implant life. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.