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.