Experimental study of the biocompatibility, corrosion behavior, and reparative properties of novel bioabsorbable Mg–Ca–Zn alloy screws with different coating thicknesses

BACKGROUND: Restoration of bone tissue damaged as a result of trauma remains a relevant challenge in modern medicine. Displaced fractures in childhood are often treated by osteosynthesis, which requires a second surgical procedure to remove fixation implants, thereby increasing operative risks. Biodegradable magnesium-based screws represent a promising solution, as they resorb in vivo and, according to available data, exhibit osteoinductive properties. AIM: To determine and evaluate the optimal biocompatibility, corrosion resistance, and reparative properties of bioresorbable Mg-Ca-Zn alloy screws in vivo and in vitro using an experimental intra-articular fracture model. METHODS: To assess reparative, bioresorptive, and biocompatible properties, bioresorbable headless cannulated compression screws with different coating thicknesses (15, 25, 35, 45, and 55 μm), a cylindrical thread diameter of 3.5 mm, and a length of 20.0 mm were implanted into the posteromedial surface of the proximal third of the tibia in Soviet Chinchilla rabbits. Animals were euthanized 2 months after experiment, followed by instrumental and histological examinations. Implant biodegradation was assessed in vivo by the presence of gas formation in bone tissue, whereas biocompatibility and the reparative bone response were evaluated based on peri-implant bone density and histological findings. RESULTS: All coated Mg–Ca–Zn screw samples demonstrated optimal biocompatibility and a favorable reparative bone response. CONCLUSION: Experimental in vivo evaluation of Mg-Ca-Zn bioresorbable screws in bone tissue showed that the implants undergo biodegradation and exhibit good biocompatibility and reparative response, indicating their fundamental feasibility for use in traumatology practice.