1-46
1-46. HEALING OF BONE
a. Bone healing follows an orderly sequence, and it begins the same as wound healing in any other part of the body. When a bone is fractured, hemorrhage between and around the bone ends will occur. Within 24 hours, a blood clot will form. This blood clot is invaded by cells that form granulation tissue. The cells in the newly formed granulation tissue differentiate and form a union of fibrous tissue known as a soft callus. This
soft callus forms a "bridge" between the broken bone ends. Bone-forming cells begin to grow within the soft callus and the soft callus is gradually formed into a hard callus (ossification). There is then a firm bony union between the broken ends of the bone. In treating a fracture, the bones are brought into proper alignment and immobilized until X-rays show that a hard callus has formed.
b. Many factors influence the healing time of fractures and certain conditions may interfere with healing. If the realignment is poor, the bone ends may not meet or there may be soft tissue interposed between the bone ends. Union will not occur under such circumstances. Likewise, if the immobilization is inefficient, union may not occur. The age and physical condition of the patient, as well as dietary deficiencies, will affect the healing time. Additional factors in healing time are the type of fracture, its location, and the adequacy of the blood supply to the affected area. Finally, the presence of infection will severely handicap healing or prevent it altogether.
Figure 1-19. Fractures.
