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

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5 signs of inflammation: pain, heat, redness, swelling, and loss of function

Pathophysiology of injury images_medium_bjcn.2012.17.3.s17_f01

  1. Injury to cell
  1. Vascular reaction (VasoDilation, --> VasoConstriction --> Exudate creates stasis)
  1. 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)

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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

  1. 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.

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Stages-of-Wound-Healing-

Davis's Law

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It is a physiological principle stating that soft tissue heal according to the manner in which they are mechanically stressed.

Wolff's Law

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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