page_title: Bone healing
section_title: Repair
hierarchical_section_title: Bone healing / Secondary healing / Repair
caption_attribution_description: English: A 26-year-old man presenting with wrist pain after being assaulted. Followup anteroposterior radiographs, 12 days later, shows obvious scaphoid fracture (arrows). Initial anteroposterior radiograph shows a subtle linear lucency within the scaphoid extending to the scaphocapitate articular surface that was overlooked (arrow).
context_page_description: Bone healing, or fracture healing, is a proliferative physiological process in which the body facilitates the repair of a bone fracture.
  Generally bone fracture treatment consists of a doctor reducing displaced bones back into place via relocation with or without anaesthetic, stabilizing their position to aid union, and then waiting for the bone's natural healing process to occur.
  Adequate nutrient intake has been found to significantly affect the integrity of the fracture repair. Age, bone type, drug therapy and pre existing bone pathology are factors which affect healing. The role of bone healing is to produce new bone without a scar as seen in other tissues which would be a structural weakness or deformity.
  The process of the entire regeneration of the bone can depend on the angle of dislocation or fracture. While the bone formation usually spans the entire duration of the healing process, in some instances, bone marrow within the fracture has healed two or fewer weeks before the final remodeling phase.
  While immobilization and surgery may facilitate healing, a fracture ultimately heals through physiological processes. The healing process is mainly determined by the periosteum.
context_section_description: Seven to nine days after fracture, the cells of the periosteum replicate and transform. The periosteal cells proximal to (on the near side of) the fracture gap develop into chondroblasts, which form hyaline cartilage. The periosteal cells distal to (at the far end of) the fracture gap develop into osteoblasts, which form woven bone through bone resorption of calcified cartilage and recruitment of bone cells and osteoclasts. The fibroblasts within the granulation tissue develop into chondroblasts which also form hyaline cartilage. These two new tissues grow in size until they unite with each other. These processes culminate in a new mass of heterogeneous tissue known as a fracture callus Callus formation peaks at day 14 of fracture. Eventually, the fracture gap is bridged
  The next phase is the replacement of the hyaline cartilage and woven bone with lamellar bone. The replacement process is known as endochondral ossification with respect to the hyaline cartilage and bony substitution with respect to the woven bone. Substitution of woven bone happens before substitution of hyaline cartilage. The lamellar bone begins forming soon after the collagen matrix of either tissue becomes mineralized At this stage, the process is induced by IL-1 and TNFα.  The mineralized matrix is penetrated by microvessel and numerous osteoblasts. The osteoblasts form new lamellar bone upon the recently exposed surface of the mineralized matrix. This new lamellar bone is in the form of  trabecular bone. Eventually, all of the woven bone and cartilage of the original fracture callus is replaced by trabecular bone, restoring most of the bone's original strength
caption: Radiolucency around a 12 day old scaphoid fracture that was initially barely visible.[6]
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