FD shows replacement of lamellar bone with abnormal metaplastic immature woven bone, forming irregular curvilinear trabeculae on histology; this appearance has been described as "Chinese characters" or alphabet soup.
At an early stage, a disintegration of the substitute material occurs and new bone starts to form trabeculae and osteonal structures like in conventional fracture healing.
It showed woven bone, forming directly in the marrow compartment and not primarily on the surface of old trabeculae.
The main part of the defect was filled with soft tissue, representing normal bone marrow between the newly formed trabeculae (Fig. 4B and C).
In contrast, the zoledronate-treated grafts appeared intact, with new bone formed around the graft trabeculae.
New woven bone formed on the surface of old trabeculae had united at the 2 sides.
IRs against fibronectin and S-100 protein were observed in the cartilage tissue, the central region of the newly formed bone trabeculae, and some of chondrocytes within the bone trabeculae.
In the present study, we observed fibronectin in the cartilage tissue, the central region of the newly formed bone trabeculae, and some of the cells within the bone trabeculae.
Osteoclasts are required during embryonic development for the removal of bone trabeculae formed under growth plates during endochondral ossification and thus for formation of the bone marrow cavity to facilitate normal hematopoiesis.
Cartilaginous remnants were clearly shown within the newly formed bone trabeculae (Fig. 10, 11), and some hypertrophic chondrocytes were also seen within the trabeculae in this phase.
