The Healing Process
Acute Injury Phase
Sub-Acute
THE INFLAMMATORY RESPONSE PHASE
THE FIBROBLASTIC REPAIR PHASE
Chronic Phase
On-set to the first 72 to 96 hours
First 2 days to 6-weeks
3 Weeks to 2+ years
5 signs of inflammation: pain, heat, redness, swelling, and loss of function
Pathophysiology of injury
- Injury to cell
- Vascular reaction (VasoDilation, --> VasoConstriction --> Exudate creates stasis)
- Cellular Response (Platelets and Leucocytes adhere to the vascular wall)
4a. Chemical mediators are liberated (Histamine, Leukotrienes, Cytokines)
4b. Phagocytosis (removal of metabolic debrie)
4c. Clot formation and hemostasis (may require unto 48 hours to complete)
Signs and Symptoms: pain and tenderness especially when movement stresses the clot or scar
Revascularization: stimulated by the lack of oxygen angiogenesis begins and capillary buds begin to make they way to the injury site.
Formation of a scar
- Granulation, the formation of delicate connective tissue consisting of fibroblasts, collagen, and capillaries
2a. Fibroblasts begin to synthesize the intercellular matrix
2b. on about day 6-7 fibroblasts begin to producing collagen fibers which are deposited in a random fashion
2c. As collagen increases so does the tensile strength leading to less activity from fibroblasts and the beginning of the maturation stage.
THE MATURATION AND REMODELING PHASE
The realignment or remodeling of of the collagen fibers that make up the scar tissue. Change happens according to the tensile forces the scar is subjected to.
Davis's Law
It is a physiological principle stating that soft tissue heal according to the manner in which they are mechanically stressed.
Wolff's Law
Bone will remodel itself over time to become stronger to resist loading stress
As appearance and function begin to return it should noted that scare tissue is not strong
Factors that impede healing
Extent of the injury:
Edema
Hemmorage
Poor Vascular Supply
Seperation of Tissue
Micro trauma: often associated with overuse
Macrotears: result in clinical symptoms and altered function
increased pressure retards healing. produces reflexive changes. impedes nutrition to injury
internal hemorrhage produces the same effects as Edema. External hemorrhage can be life-threatening
Heal poorly and at a slower rate. Due to poor delivery of phagocytic cells in the early stage and fibroblasts reaction in the remodeling stage.
degree of mechanical separation. smooth edges vs jagged edge determines the level of granulation and ultimately the scars outcome
Other Factors include
Muscle Spasm, Atrophy, Corticosteroids, Keloids and hypertrophic scaring, Infection, Humidity, Climate, and Oxygen tension, Health, Age, and Nutrition