Feasibility of Ti-6Al-4V Alloys with Nanoporous and Nanotubular Surfaces for the Treatment of Femoral Defects

Treating fractures involving complex bone defects remains a major challenge in regenerative medicine. Additive manufacturing enables the fabrication of patient-specific implants, while surface anodization may enhance osseointegration by improving cell adhesion at the bone–implant interface. This study evaluated the feasibility of porous Ti-6Al-4V implants produced by additive manufacturing and surface-modified by anodization for repairing critical-sized femoral defects. Eighty rats were assigned to four groups: control (no graft), non-anodized Ti-6Al-4V implants, nanoporous implants, and nanotubular implants. After six weeks, bone regeneration and mechanical performance were assessed. Newly formed bone volume was significantly higher in the implanted groups compared to control (24.62 ± 3.11%), reaching 47.25 ± 3.92% (non-anodized), 58.20 ± 5.39% (nanoporous), and 40.72 ± 2.22% (nanotubular). Bone strength was also greater in implanted groups (150.27 ± 2.94 N, 151.98 ± 10.37 N, and 156.59 ± 4.95 N, respectively) compared to control (128.16 ± 2.17 N), with no significant differences among treated groups. No signs of implant rejection or inflammation were observed, indicating good biocompatibility. Anodized surfaces demonstrated enhanced osteogenic performance, particularly in the nanoporous group. These findings indicate that anodized porous Ti-6Al-4V implants produced by additive manufacturing combine biological compatibility with mechanical stability, supporting their potential application in bone reconstruction therapies.