Design and Optimization of Carbon Fiber Reinforced Terpolymer for Use in Orthopedics

Abstract

Medical implants such as intramedullary rods and fixation screws are life-changing for those who experience fracture injuries. Titanium alloys making up intramedullary rods allow for longevity of the implant with high strength and low weight, while also causing stress shielding leading to bone death and potentially difficult revision surgery. It is well understood that load is transferred primarily through the implant as it has a higher modulus than that of cancellous bone. Research into alternative, less invasive methods to fracture fixation considers ceramic and polymer composite systems that closely match the bone’s mechanical properties to reduce stress concentration and shielding. Herein, we designed and optimized an implantation device and method that is both less invasive and allows for tailored properties to the host bone in which it is implanted. Using FDA-approved materials, we synthesized a photoinitiated triblock copolymer reinforced with carbon fiber allowing for high modulus with lower heat of polymerization than commercially available bone cement. This research achieved a polymer system capable of being injected and polymerizing in 15 minutes that can bear loads up to 7GPa in flexure.