Bone Healing Process
Bone forming cells known as osteoblasts begin traversing from the bloody ends of the defect into the hematoma that has formed at the injury site. Slowly, the matrix mineralizes into bone by incorporating calcium and phosphate.
Osteoblasts are caught up in the advancing mineralization front and are trapped.
Osteoblasts then transform into osteocytes.
The newly bridged bone defect undergoes remodeling, or rebuilding from a woven immature state.
Bone then remodels to a mature lamellar configuration.
Read a more detailed description of bone healing.
Angiogenesis, the formation of blood vessels, plays an important role in bone healing. When bone fractures, platelets and a host of inflammatory cells and mesenchymal cells enter the fracture site. The mesenchymal cells proliferate and differentiate into chondrocytes. The chondrocytes secrete cartilage matrix, forming a soft callus that eventually calcifies. One of the earliest processes in remodeling of the calcified callus involves invasion of blood vessels. This process brings in cells such as osteoclasts and osteoblasts that resorb the hard callus and deposit bone matrix, respectively. Vascularization also facilitates remodeling of the bone that forms on the calcified cartilage scaffold.
