Stages of wound healing

Physiological Stages

Physiological Stages of Wound Repair

1.) Inflammatory Phase

• Initial response to injury
• Day 1-4 post injury
• Characterized by rubor, tumor, dolor, calor
• Platelet aggregation and activation
• Leukocyte (PMNs, macrophages) migration, phagocytosis and mediator release
• Venule dilation
• Lymphatic blockade
• Exudative
• In wounds closed by primary intention, lasts 4 days
• In wounds closed by secondary or tertiary intention, continues until epithelialization is complete

2.) Proliferative Phase

• Day 4-42
• Fibroblast proliferation stimulated by macrophage-released growth factors
• Increased rate of collagen synthesis by fibroblasts
• Granulation tissue and neovascularization
• Gain in tensile strength

3.) Remodeling Phase

• 6wks-1 year
• Intermolecular cross-linking of collagen via vitamin C-dependent hydroxylation
• Characterized by increase in tensile strength
• Type III collagen replaced with type I
• Scar flattens