Cellular interactions and bone healing responses to a novel porous tricalcium phosphate bone graft material

The use of a porous tricalcium phosphate bone void filler (Cellplex TCP, Wright Medical Technology, Inc, Arlington, Tenn) as an alternative to autograft in bone grafting was studied in benchtop, in vitro cell culture, and in vivo preclinical studies. The experimental design included material property quantification, scaffold seeding with mesenchymal stem cells, and implantation in a rabbit segmental defect model. Measured material properties denoted appropriate composition, porosity, and strengths as compared to the literature. Fluid uptake studies and mesenchymal stem cell affinity revealed the scaffold's capabilities as a suitable host for osteoprogenitor cells. In a 1-cm rabbit diaphyseal segmental defect stabilized with an external fixator, tricalcium phosphate was compared to intact autograft, crushed autograft, and open defects. Torsional strengths and stiffnesses of tricalcium phosphate-treated tibia were greater than or equivalent to both intact and crushed autograft controls. Tricalcium phosphate pores exhibited complete bony infiltration histologically. Collectively, the tricalcium phosphate material properties, cell seeding capabilities, and in vivo biological responses give evidence of this implant's functionality as a potential alternative for autograft.