Viable osteoblastic potential of cortical reamings from intramedullary nailing

To analyze the effect of intramedullary reaming on fracture healing, we investigated whether or not cortical reamings contain viable bone cells. There are several tissue components contained in medullary reamings including blood, bone marrow and cortical bone. This study is focused on the cortical reamings, which are produced during reaming of the medullary cavity. They may stimulate fracture healing but it is still unclear if they contain vital bone cells. We tested the hypothesis that these cortical reamings are a source of viable bone cells and compared cell cultures with cultivated cells from iliac crest biopsies. Responses of protein content and ALP activity to vitD stimulation in the cells were considered as properties of viability. Ten in tact living sheep femora were fully reamed and the cortical reamings were cultivated in a standard manner and compared with cultivated cells from ipsi-lateral iliac crest biopsies from the same animals. Cells started to grow from the reamings as well as the iliac crest within 2-5 days, and covered the entire culture flask within 9-13 days. Protein content and ALP activity in cells from both reamings and iliac crest were significantly responsive to vitD stimulation. Cortical reamings from intramedullary nailing have osteoblastic potential and contain living bone cells similar to bone cells from the iliac crest. These findings may further explain the superior healing of fractures, treated with reamed nailing.