The correlations between the scaffold porosity or pore size and the number of active osteoblasts, endothelial cells, and bone mass. (a) After 8 weeks, predicted numbers of active osteoblasts and endothelial cells, and bone mass formation showed a greater correlation to scaffold porosity than to scaffold pore sizes. (b) Numbers of active osteoblasts (OBa) and endothelial cells (ECs), as well as bone mass formation, were strongly related to porosity. "Normalized values" indicates that these values were normalized to their original maximum values.