Objective:To explore the repairing effects of 3D-printed nano-β-tricalcium phosphate (β-TCP) scaffolds loaded with vancomycin and bone morphogenetic protein-2 (BMP-2) for seawater -soaked tibial bone defects in rabbits. Methods:A total of 27 male New Zealand White rabbits were assigned to the normal group using a random number table method, with each group consisting of 9 rabbits. The rabbit tibial bone defect model was created using the osteotomy surgical method. Eight hours after operation, the wounds in the control group and seawater group were immersed in seawater for 2 hours, and those in the normal group were not immersed. After an observation period of 5-7 days, no significant redness or purulent discharge was observed in the wound appearance, then debridement was performed followed by corresponding implantations: the control group with gelatin sponges loaded with vancomycin and BMP-2, and the other two groups with 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2. After filling the bone defects with the respective materials, all groups underwent layer-by-layer suturing of the wound, followed by disinfection with iodine and injection of gentamicin to prevent infection. The affected limbs were then immobilized using a plaster cast. The affected limbs were imaged using anteroposterior X-ray at 4, 8 and 16 weeks after operation, and the repair effects were evaluated using the Lane-Sandhu X-ray scoring system. At 16 weeks after operation, the bone defect tissues were collected for HE staining to observe bone tissue growth.Results:At 4 weeks after operation, the Lane-Sandhu X-ray score in the control group was significantly lower than that in the normal group [(2.8±1.1)points vs. (1.1±0.9)points] ( P<0.05), and that in the seawater group [(2.2±1.0)points] was not significantly different from those in the other two groups (all P>0.05). At 8 weeks after operation, the seawater group [(6.1±0.9)points] and the control group [(2.8±1.0)points] exhibited lower Lane-Sandhu X-ray score compared to the normal group [(8.2±1.0)points] (all P<0.05), and the seawater group showed a higher score compared to the control group ( P<0.05). At 16 weeks after operation, the control group [(3.8±1.0)points] exhibited a lower Lane-Sandhu X-ray score compared to the normal group [(10.0±1.3)points] and the seawater group [(9.3±1.2)points] (all P<0.05), while no significant difference was noted between the latter two ( P>0.05). At 16 weeks after operation, histological observations revealed varying degrees of bone tissue formation in three groups, with the normal group showing the best bone defect repair effect, followed by the seawater group. Conclusion:The 3D-printed nano-β-TCP scaffolds loaded with vancomycin and BMP-2 are effective for the treatment of seawater -soaked bone defects, which can promote bone tissue repair.