University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

147

Pages:

2
Author:

Mariam A.

Fracture Healing Simple fractures    Early stage: resembles healing of skin wound by second intention o Disruption of blood vessels within the bone, periosteum and surrounded soft tissues o Formation of a haematoma between fracture ends and beneath the periosteum o Organisation of haematoma by an in-growth of capillaries and fibroblasts, becoming granulation tissue o Inflammation with infiltration by neutrophils followed by macrophages – they remove haematoma and tissue debris Intermediate stage: formation of the callus consisting of new vessels, fibrous tissues, cartilages and woven bone, produced by cells from periosteum and the ends of the fractured bone o Internal callus forms in the original medullary cavity o Intermediate callus forms in the cortex o External callus forms on the surface from the inner layer of periosteum o Note: The principal cell type is the osteoblast, derived from both the broken bone and the periosteum. Woven bone is formed first from osteoid, which is then mineralised. There may also be formation of hyaline cartilage if there is immobilisation or if the blood supply is poor (the progenitor cells have the morphology of chondroblasts). The ends of the fracture are eventually united by a provisional callus Late stage: remodelling, with complete or partial reconstruction of the original bone associated with acquiring full mechanical strength (can take up to months or years) o Mineralisation of any cartilage and its subsequent ossification o Osteoclasts remove dead bone and surplus woven bone o Osteoblasts form new bone trabeculae in which the lamellae have an orientation determined by mechanical forces acting on the provisional callus Other types of fractures      The sequence of events is generally similar to that of a simple fracture. It is usually, however, slower, as the callus is more abundant, the remodelling slower and the final outcome is usually not as good For optimum healing of an open/compound fracture, surgery is required with debridement and skin closure, provided the wound is not grossly contaminated For comminuted fractures, if the bone is shattered, the reconstitution of the original structure is generally poor In stress fractures, changes will consist of both those of repair and the new fracture. In pathological fractures, attempts at repair are evident, but are usually inadequate, since the healing process is generally compromised by the underlying pathological process.