Bioabsorbable interlocked nail system for 3D printed segmental bone defects

Abstract

Advancements in three-dimensional (3D) printing and biomaterials have revolutionized bioengineering, particularly in medical applications. This study aims to develop cost-effective bioabsorbable scaffolds and interlocked nails for bone repair, focusing on segmental bone defects, which can cause significant functional impairments and cosmetic deformities. The research utilizes a rabbit tibia model to test the efficacy of these innovations. Bioabsorbable scaffolds and interlocked nails show promise in enhancing bone repair outcomes and minimizing the need for additional surgeries. Using 3D printing to fabricate these systems has proven more effective than traditional methods. The study employs biocompatible and biodegradable materials, specifically polycaprolactone (PCL) and PCL combined with MgO, to create the scaffold, interlocking nail, and screws through a phase separation casting method. This technique allows precise control over the scaffold's pore structure and size and facilitates the incorporation of bioactive agents or cells into the scaffold matrix. In the first phase of the study, the PCL scaffolds demonstrated suitability for accelerated degradation and early weight-bearing capacity. The second phase focused on the accurate placement of the scaffold and fixation system using the rabbit tibia model. A surgical jig was designed and fabricated from biocompatible resin, with a 3D model printed using computer-aided design (CAD) software. Stereolithography (SLA) 3D printing technology was employed in the photopolymerization process, followed by UV light curing to enhance the jig's strength. Experiments on cadaver models using New Zealand white rabbits confirmed that the scaffold, intramedullary nail, and screw system are strong enough to support load-bearing areas of surgical insertions. The designed prototype shows potential for further clinical translational studies, demonstrating the effectiveness and practical application of the scaffold and fixation system in reconstructive surgeries for long-bone segmental defects.