a-Mean percent bone volume (BV/TV), b-trabecular number (Tb.N), c-trabecular thickness (Tb.Th), and d-trabecular separation (Tb.Sp) of defect by treatment, 4 weeks post-op. * indicates significant difference compared to BMP-2+SDF-1β group. # indicates significant difference when compared to BMP-2 and BMP-2+SDF-1β respectively. & indicates a significant difference when compared to Control, SDF-1β, TGF-β1, and TGF-β1+SDF-1β respectively.