In Vivo Rat Model Study of Nanocomposite Coated Magnesium-Based Alloy and 3D Printed PLA Implants for Long Bone Regeneration Applications

Orthopedic implants play a vital role in restoring function in patients with bone and joint disorders, yet improving their biocompatibility and mechanical strength remains a challenge. This study evaluates the in vivo performance of 3D-printed poly L-lactic acid (PLA) and AZ31 magnesium (Mg) alloy implants coated with titanium-zirconium (Ti-Zr) and titanium hydroxyapatite (Ti-HA) nanocomposites using a Wistar rat model. The implants' degradation rates over 60 days were observed, with Mg (Ti-Zr) and Mg (Ti-HA) showing reduced degradation (25 and 32%, respectively) compared to uncoated materials. Nano-CT analysis confirmed progressive bone regeneration, with healing improving from 10-15% at day 30 to 60-70% at day 60. Histological analysis revealed osteoblast and osteoclast activity, indicating effective bone remodeling. These findings suggest that Ti-Zr and Ti-HA nanocomposite-coated Mg implants offer enhanced corrosion resistance, mechanical stability, and biocompatibility. This study's findings suggest the potential to enhance the efficacy of orthopedic therapies and to advance the creation of functional implants that fulfill patient requirements with superior performance, durability, and compliance. Further optimization may establish these coatings as promising candidates for clinical orthopedic applications.