Fig. 2

Radiographic assessment of bone formation. The representative radiographs of the bone mineral density in four groups at each time-point. The callus formation and union were observed by direct radiographs taken at 4, 8, and 12 weeks after the second operation. The white arrows over the images indicate the region of interest. a Sham group, b isolated α-CSH group, c α-CSH/ACB mix group, d isolated ACB group, n = 7