Banked bone grafting for bone defect repair--clinical evaluation of bone union and graft incorporation.

One hundred and twenty-four banked bone grafts performed during the past 15 years were studied in respect to union and graft incorporation processes using X-ray, bone scintigraphy and histology. Radiological study of the chip graft showed an absence of cavity contours, and homogenization of the grafted area, followed by development of the trabecular structure. In the block graft, initial union was shown at the junctional area followed by the appearance of mottled shadows throughout the entire graft and finally differentiation of bone marrow and cortex. Bone scintigraphy showed an initial increase in RI uptake at the junction and then a gradual increase in the entire graft. Histological study showed that bone apposition on the trabeculae of the graft starts in the junction and later extends to other areas. The replacement of cancellous bone is more rapid than that of cortical bone. The porous surface seems to promote bone union and incorporation when large block grafts of cortical bone are used.