The role of local stem cells is considered decisive for the outcome of this healing process 1112 . The metaphyseal marrow possesses a high number of MSCs, which present a higher degree of interaction with immune cells and an elevated division, and a higher ratio of following an osteogenic fate compared to diaphyseal MSCs . In the diaphysis on the other hand, recruitment of mesenchymal progenitor cells is necessary for optimal bone formation, as local diaphyseal MSCs are not enough in number and activity to effectively support bone regeneration.