Comparison of tendon attachment to 3D printed Ti6Al4V implant versus Trevira® implant: A paired experimental animal study

Background: Soft-tissue attachment is crucial for the success of megaprosthesis surgery and improvement in current treatment is needed. The aim of this study was to compare the biomechanical and histomorphometric properties of soft-tissue attachment between 3D printed Ti6Al4V implants featuring a 630 mu m microporous structure and commercially available Trevira (R) implants with a 200 mu m porous structure in a non-loadbearing ovine model. Methods: Ten skeletally mature ewes underwent surgical implantation with both implants. After 4-weeks, mechanical pull-out testing assessed the attachment strength, while histomorphometric analysis evaluated fibroblast cell profile density, multinucleated giant cell profile density, microvessel length and volume density. Results: 3D printed Ti6Al4V implants demonstrated a 129% greater attachment strength compared to Trevira (R) implants (p = 0.003). In the Trevira (R) group, a 35% increase in fibroblast profile density (p < 0.001) and a 98% increase in multinucleated giant cell profile density (p < 0.001) were observed, with no significant difference in microvessel length density between the groups. However, the Ti6Al4V group exhibited a 50% higher microvessel volume density (p < 0.001) compared to the Trevira (R) group. Conclusion: 3D printed Ti6Al4V implants with a 630 mu m microporous structure demonstrated superior attachment strength, enhanced neovascularization, and reduced foreign body reaction compared to the Trevira (R) implants. These findings suggest that 3D printed Ti6Al4V implants may enhance soft-tissue attachment in megaprosthesis surgeries.