Primary calcification in remodeling haversian systems following tibial fracture in rats.

Electron micrographs of fracture callus obtained ten days after injury show typical primary matrix vesicle mineralization. In remodeling haversian canals distant from the fracture sites, matrix vesicles and calcifying nodules were observed. The occurrence of these elements was also found to control unfractured tibiae with intramedullary nails but not normal bone. These observations suggest that during haversian remodeling, mineralization after osseous or marrow tissue damage is associated with matrix vesicles.