積層製造高孔洞生物可吸收鐵基介面螺釘及縫合錨釘的生物相容性及功效性評估研究

The primary objective of this study was to evaluate the biomechanical properties, biocompatibility, and biological performance of bioabsorbable iron-based interference screws (ISs) manufactured using additive manufacturing technology over a 12-month mid-term period. Two types of bioabsorbable iron ISs were investigated: one made from pure iron powder (iron_IS) and the other incorporating 0.2 wt% tricalcium phosphate (TCP_IS) into pure iron powder. These bioabsorbable iron ISs were compared to conventional metallic ISs (control) through in vitro biocompatibility and degradation analyses, as well as an in vivo animal study. Results indicated that at 3 months post-operatively, both iron_IS and TCP_IS exhibited significantly higher ultimate failure strength compared to the control ISs in the in vitro tests. However, beyond this time point, the differences in strength between the groups were no longer statistically significant. Additionally, at the 3-month mark following implantation, iron_IS and TCP_IS implants led to increased bone volume fraction, bone surface area fraction, and percent intersection surface. Subsequently, these parameters remained stable without significant changes. Furthermore, both iron_IS and TCP_IS implants demonstrated degradation over time, characterized by increased implant surface area, decreased implant volume, and reduction in structure thickness. Importantly, the analysis of visceral organs and biochemical parameters showed normal results, except for the presence of time-dependent iron deposition in the spleen. Compared to conventional ISs, bioabsorbable iron-based ISs demonstrate a higher initial mechanical strength. However, it is important to note that although iron-based ISs exhibit high biocompatibility even after 12 months of implantation, there is a concern regarding the accumulation of corrosive iron products in the spleen. Nonetheless, due to their mechanical superiority and substantial absorption capability following implantation, iron-based ISs hold promising potential for future applications in the development of implantable medical devices.