CORTICAL
CANCELLOUS
Cortical bone grafts revascularise slowly. They are not permeated by the blood vessels until 6-7days and graft is not completely vascular till 12months. This delay may be due to the need to open, by the osteoclastic activity, the existing Volkmanns canals and Haversian system. It may also be due to smaller no of endosteal cells available for the end to end anestamosis.
There is end to end anestomosis of host with grafted vessels. This together with the process of in-growth into the marrow spaces takes place with in 2 weeks. This revascularization also allows the grafted cells and host cells, induced by osteogenic cells, to differentiate into osteoblasts. They surround isolate dead bone and account for increased radiodensity of graft initially.
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