Bioactive coatings of metallic orthopedic implants: functional properties and clinical potential

Use of metallic orthopedic implants (screws, plates, intramedullary rods) has several problems, such as inadequate biological integration and high infection risk. This review summarizes current insights on functional coatings for metallic orthopedic implants concerning their osteoinductive, osteoconductive, immunomodulatory, and antimicrobial properties and evaluating their clinical application potential. Key bioactive coatings include hydroxyapatite and bioactive glass, along with nanostructured and ion-doped layers. The deposition techniques, namely plasma spraying, sol-gel technology, anodization, electrophoretic deposition, and gas-detonation spraying, are analyzed. It is ascertained that hydroxyapatite and bioactive glass coatings substantially enhance biocompatibility and osseointegration. Ion doping (strontium, zinc, magnesium) further boosts osteoinductive properties, while nanostructuring enhances cell adhesion and minimizes inflammatory responses. Antimicrobial coatings with silver, antibiotics, and bactericidal agents significantly reduce infectious complications. Among coating deposition methods, plasma spraying, sol-gel processes, and gas-detonation spraying show notable industrial applicability. Multifunctional and “smart” coatings demonstrate strong clinical efficiency and promise widespread adoption. Advancements in coating technology and optimization of material compositions will decrease complications and enhance treatment outcomes for patients with bone injuries and defects.