Fig. 6

Histological analysis. Representative histological sections at the distracted callus stained with hematoxylin and eosin. a The histology of the distraction phase by the protocol in group N. b The histology of the consolidation phase by the protocol in group N. c The histology of the distraction phase by the protocol in group D + C. d The histology of the consolidation phase by the protocol in group D + C. Each of histological images a–d was high-power fields of the area around the distal part of the osteotomy where new bone is beginning to appear. Chondrocytes were abundant in the distracted callus 2 weeks after the osteotomy (distraction phase), and a new bone was formed by endochondral ossification. The woven bone with some cartilage is predominant. Almost no chondrocytes were observed in the distracted callus 4 weeks after osteotomy (consolidation phase), and a new bone was formed by intramembranous ossification. The mature lamellar bone is predominant. Car cartilage cell, Nb new bone, Cb cortical bone, 2w 2 weeks after the osteotomy, 3w 3 weeks after the osteotomy, 4w 4 weeks after the osteotomy