Development of a Bioabsorbable Glass-Reinforced-Glass Intra-Osseous Scaffold for Fracture Healing

Abstract

Intramedullary (IM) nails are routinely used to stabilize long bone fractures. They can however lead to stress shielding, pain, migration, obstruct hematopoietic tissue, become a loci for infection, and require subsequent surgical retrieval. Novel intra-osseous scaffold (IOS™) prototypes for fracture healing have been developed to function as a regenerative scaffold to enhance callous formation under mechanically stabilized conditions then resorb. Prototype fixation pins and rod systems were formed from glass-reinforced-glass. Flexion, torsion and shear tests were performed to evaluate the composite pins and rods. A modular rod design was successfully deployed and dilated while in a deformable state. When fitted and gripping the intramedullary canal then set in a rigid state. An obliquely sectioned ovine femur was used as a long bone fracture model for deployment and mechanical verification. Flexural support provided by the intramedullary scaffold was superior to multiple k-wire fixation, while the k-wire approach was more stabilizing under torsional loads. Glass reinforced glass samples were mechanically tested after soaking for up to 4 weeks in saline. Strength and modulus of the composite was reduced to approximately 25% of initial values after 2 weeks.