Three-dimensional Reconstruction of Fracture Callus Morphogenesis

Abstract

(KJJ) S U M M A R Y Rat and mouse femur and tibia fracture calluses were collected over various time increments of healing. Serial sections were produced at spatial segments across the fracture callus. Standard histological methods and in situ hybridization to col1a1 and col2a1 mRNAs were used to define areas of cartilage and bone formation as well as tissue areas undergoing remodeling. Computer-assisted reconstructions of histological sections were used to generate three-dimensional images of the spatial morphogenesis of the fracture calluses. Endochondral bone formation occurred in an asymmetrical manner in both the femur and tibia, with cartilage tissues seen primarily proximal or distal to the fractures in the respective calluses of these bones. Remodeling of the calcified cartilage proceeded from the edges of the callus inward toward the fracture producing an inner-supporting trabecular structure over which a thin outer cortical shell forms. These data suggest that the specific developmental mechanisms that control the asymmetrical pattern of endochondral bone formation in fracture healing recapitulated the original asymmetry of development of a given bone because femur and tibia grow predominantly from their respective distal and proximal physis. These data further show that remodeling of the calcified cartilage produces a trabecular bone structure unique to fracture healing that provides the rapid regain in weight-bearing capacity to the injured bone.

Raman spectroscopy of bone composition during healing of subcritical calvarial defects

“…The peak of the hard callus development is usually reached by day 14 as defined by histomorphometry of mineralized tissue [39]. The calcified cartilage is replaced with woven bone as the hard callus formation progresses and it becomes mechanically rigid and more solid [40]. Figure 6 shows digital microscope images of surface, control and in vivo defects on parietal bones after 7 and 14 days under 300X magnification.…”

Nano-copper-bearing stainless steel promotes fracture healing by accelerating the callus evolution process

“…38 Subsequently, the callus gradually remodels with time. The arrangement of trabecular bone (from loose to tight) and the formation of bony connections are the main steps in this process.…”

Temporal tissue patterns in bone healing of sheep

“…The outcome of animal experiments is commonly reported by means of histological images at different time points post-operatively and accurate qualitative histological descriptions and observations. 9,18 Depending on the harvesting time, these histological sections show an intricate pattern of different tissue types including hematoma, fibrous tissue, cartilage, mineralized cartilage, and the newly formed bone (as an example, see Fig. 1).…”