Tissue Healing Process Flashcards
What are the 4 stages of tissue healing?
- Haemostasis (First 4-6 hours)
- Inflammation (Day 1 - days / weeks)
- Proliferation (Day 5-7 - up to Week 4)
- Remodelling (Week 4 - months / years)
What occurs in the haemostasis stage of tissue healing?
- first stage (first 4-6 hours post injury); process of the wound being closed by blood clotting cascade
a. blood vessels constrict (vascular spasm) in response to injury
b. platelets coagulate to form a plug over the injured tissue
c. blood coagulates and reinforces platelet plug with fibrin, thrombus / clot forms
What occurs in the inflammation stage of tissue healing?
- second stage (day 1 - days / weeks post injury; maximum inflammation days 1-3)
a. infiltration of WBCs, antibodies and nutrients
b. phagocytic activity to clear damaged tissue, pathogens and bacteria
What occurs in the proliferation stage of tissue healing?
- third stage (day 5-7 for up to 4 weeks); wound is rebuilt with new tissue made up of collagen and extracellular matrix
a. fibroblasts lay down new collagen fibres (type III, disorganized and thick)
b. myofibroblasts draw the edges of the wound towards each other
c. new vasculature formed to service the area
d. epithelial cells resurface the injured area
What occurs in the remodelling stage of healing?
- fourth and final stage (from 4 weeks, for months - years)
a. wound closed
b. collagen is remodelled from type III (disorganized and thick) to type I
c. collagen is aligned along tension lines and forms cross-links (reduces scar tissue and increases tensile strength)
Which factors can inhibit tissue healing?
- older age
- co-morbidities and chronic disease (CVD, diabetes, cancer)
- immunosuppresion
- radiation or chemotherapy
- inadequate nutrition or sleep
- alcohol, tobacco and drug use
- stress
What are the typical healing time frames for a muscular injury?
DOMS: 1-3 days
Grade 1: 2-3 weeks
Grade 2: 3 weeks - 3 months
Grade 3: surgical repair (6 weeks - 6 months)
What are the typical healing time frames for a ligamentous injury?
Grade 1: 1-4 weeks
Grade 2: 3 weeks - 6 months
Grade 3: surgical repair (6 weeks - 12 months)
Note: intra-articular ligaments typically take longer to heal (1 year plus)
What are the typical healing timeframes for a tendinous injury?
Acute: 3 weeks - 3 months
Subacute: 2 -6 months
Chronic: 3 - 18 months
Complete rupture: 3 - 18 months
What are the 4 types of neural injury?
Grade 1: Neurapraxia
- demyleination, axon intact
- up to 3 months recovery
Grade 2: Axonotmesis
- myelin intact, axon damaged
- Wallerian degeneration occurs
- slow recovery of 1mm / day (months - years)
Grade 3: Neurotmesis
- myelin and axon both damaged
- surgery, full repair not possible
Radiculopathy or spinal nerve compression
- compression, irritation or inflammation or spinal or peripheral nerve
- SSX reduction in 1-3 weeks; resolution 3 months - 3 years
What are the typical healing timeframes for a neural injury?
Grade 1 (neurapraxia): up to 3 months Grade 2 (axonotmesis): 1mm/day (months -years) Grade 3 (neurotmesis): surgical repair
Radiculopathy or spinal nerve compression: SSX reduction in 1-3 weeks; full resolution 3 months - 3 years
What are the typical healing timeframes for a bone fracture?
Small bones: 3-4 weeks
Medium bones: 4-8 weeks
Large bones: 8-12 weeks
What is the typical healing timeframe for a Grade 2 sprain?
3 weeks - 6 months
What is the typical healing timeframe for an acute tendinous injury?
3 weeks - 3 months
What is the typical healing timeframe for a fractured medium size bone?
4-8 weeks
