In-situ synthesized hydroxyapatite whiskers on 3D printed titanium cages enhanced osteointegration in a goat spinal fusion model

Abstract

3D printed porous titanium cage is believed with physiology mechanical properties and biocompatibility for orthopedic usage. Typical split cage design with a grafting window and infilled bone graft has raised a lot of questions. In this research, a modified hydrothermal approach, employing chelated calcium to enhance the medium stability and increase the generated amount, is proposed to construct bioactive hydroxyapatite coating inside the porous structure of 3D printed porous titanium cage. The in vitro and transcriptomic results indicated the hydroxyapatite enhanced the cells physical sensing system, therefore enhanced the osteogenesis inside titanium/hydroxyapatite cage. The in vivo goat spinal fusion experiment indicated the integrative titanium/hydroxyapatite cage, compared with typical split cage/graft cage, showed better bone tissue ingrowth and spinal fusion ability. This research provides a promising hydroxyapatite coating strategy for complex porous structure and revealed the potential advantage of integrative titanium/hydroxyapatite intervertebral cage design.

Keywords

• 3D printing
• Hydroxyapatite coating
• Spinal fusion
• Orthopedic implant
• Hydrothermal process