Introduction: 3D printing, or additive manufacturing, is a modern technique for creating three-dimensional physical objects. It is used in reconstructive medicine and requires the use of new materials. Among biodegradable polymers, polyhydroxyalkanoates (PHAs) are prominent. They benefit from direct fermentation, which does not require complex technological stages like polylactide and polycaprolactone. Varying the substrate or producer strain allows polymers with different properties to be obtained.

Methods: First, the filament was obtained through the extrusion of P(3HB-co-3HV). For printing, we used FDM technology on a 3D printer with the author’s blowing system. This made it possible to reduce thermal deformation when creating cylindrical scaffolds with a diameter of 13 mm, a height of 4 mm, and a porosity of 65%.

To study biological compatibility, light and fluorescence microscopy were used, as well as an MTT test on a culture of NIH 3T3 mouse fibroblasts.

The implantation of 3D scaffolds was studied on a model of segmental osteotomy of the tibia in two pigs. In each animal, a bone cavity for implantation was formed in the central part of the femoral diaphysis. After the operation, the animals were monitored, measuring body temperature, heart rate, and respiration. This study was conducted ethically and with humane treatment of animals.

The statistical analysis of the results was carried out using traditional methods, with data presented as the mean ± error for 95% confidence intervals.

Results and Conclusions: The results showed the high biocompatibility of the scaffolds: microscopy, fluorescent staining, and the MTT test confirmed their complete filling with cells, which maintained their metabolic activity for up to 10 days.

Histological and X-ray analyzses showed complete healing of the defect within 5 months. These findings suggest that the designed absorbable 3D scaffolds are promising for use in bone grafting.