الفهرس 
Bone healingOnly 14 pages are availabe for public view
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Abstract
Fracture union is gradual continuous process where by the strength of broken bone is restored by a process of bone regeneration . Delayed union is the state the expression to union has not been observed at specified time, failure to see evidence of union on radiographs .But non union is the failure of fracture to demonstrate healing , despite adequate time giving , the fracture will never unite without intervention .
The factors affecting fracture healing can be divided into local and systemic factors. Local factors include degree of local trauma , Type of bone involved , degree of immobilization & micro-motion , infection , pathological fracture , a vascular necrosis, intra-articular fractures and exercise and local stress . While systemic factors include age, hormones, nutrition, diabetes mellitus, smoking and drugs.
Non union classified according to callus & Radiography into two types. First is hypertophic nonunion; the ends of fragments are hyper-vascular and capable of biological reaction, posses’ adequate vascularity, produces abundant endosteal callus seeds off medullary canal, radiolucent gap bridged by fibrocartilagenous tissue without Osteogenic capacity. Second type is avascular; incapable of biological reaction, poor blood supply to the ends of fragment, no periosteal or endosteal callus, radiolucent gap bridged by fibrous tissue without osteogenic capacity and resorbed fracture surfaces which are osteopenic.
The general principles of nonunion treatment: provide stability-rigid fixation improve biology at nonunion, do not disturb vascularity, restore mechanical axis (correct deformity and length). Restore normal function.
And the standard treatment is mechanical stabilization and biological stimulation. So enhancement of fracture healing can be divided into biological , mechanical, physical ,and vascular enhancement .