1) ST & Bone Healing Flashcards
What are the 5 phases of healing?
1) Injury
2) Hemostasis & Degeneration
3) Inflammation
4) Proliferation & Migration
5) Remodeling & Maturation
What happens during the hemostasis & degeneration phases of healing?
HEMOSTASIS: Blood vessels seal
Clots form to build fibrin lattice–>These platelets release GF’s to call inflammatory cells to the tissue
DEGENERATION: Hematoma, Necrosis, Inflammatory response
In the hemostatic phase of healing, what do platelets do (besides form the fibrin lattice)?
Release GF’s
What is the purpose of the fibrin lattice?
Source of tensile strength to the healing wound
What type of responses occur during the inflammation phase of healing?
Cellular, Vascular, Humoral, Neurological
What occurs with the vascular response of the inflammation phase?
Vasodilation (mediated by histamine, bradykinin, hageman factor, & prostoglandins)
Incr hemoconcentration to incr blood viscosity to slow blood flow from damaged vessels
Edema
Accumulation & adherence of WBC’s to damaged vessels
What occurs with the humoral response of the inflammation phase?
Activation of the complement system which stims leukocytes
Incr vascular permeability
Phagocytosis
What occurs with the neurologic response of the inflammation phase?
Glucocorticoids are released to regulate WBC fxn
SNS stims hypothalamus to regulate vascular response
What occurs with the cellular response of the inflammation phase?
Pathogen is killed & removed
T-cells activate inflammatory mediators
B-cells make antibodies
Macrophages eat
What occurs during the proliferation phase of healing?
Neovascularization
Epithelialization
Collagenization
What is the purpose of epithelialization?
Provides a barrier to the wound to prevent fluid & electrolyte loss & decr infection risk
What occurs during neovascularization in proliferation?
Macrophages stim the release of GF’s
Angiogenesis
Fibroblasts move into unhealthy tissue & proliferate
What is the timeline of collagen during healing?
Type 3 collagen is layed down initially
Day 7: There’s a significant amount of collagen, which incr the tensile strength of the wound
Day 12: Type 1 collagen replaces type 3
Day 21: Max collagen production; Strength is 20% of normal
6th wk: Strength is 80% of normal
What occurs during the maturation phase of healing?
Collagen Synthesis
Collagen Fiber Orientation
Injury is healed
What day of healing does the maturation phase start on?
Day 9
What is the longest phase of healing?
Maturation phase
How long does collagen synthesis last for?
1-2yrs
What will happen if the basement membrane of the lung is not intact?
Fibrosis so decr gas exchange & restrictive lung disease
What direction do gut cells reproduce?
Proximal to distal
True or false: Neurons & axons in the CNS & PNS regenerate similarly?
True
What occurs as a result of damage to neurons & axons?
Glial cells are stimulated to form a fibrous glial scar
In the PNS, where does wallerian degeneration occur in relation to the injury?
Distally
Is glial scarring in the PNS an issue?
No
Which CN’s have limited to capacity for regeneration?
1,2,6, & 9-12
Which CN’s can make a slow, full recovery?
2-5, 7
Which CN rarely regenerates?
8
If the endomysium of a muscle is not intact or the muscle has chronic inflammation, what will happen?
Necrosis/Fibrosis
What is the purpose of remobilization for muscle strains?
Incr fiber regeneration
Improved fiber orientation
Decr scarring
After a tendon injury, how long does the maturation phase take?
2-16wks
After a tendon injury, how long does it take for full tensile strength to be regained?
Up to 50wks
What is the rehab protocol for a sutured tendon?
Rest for inital 3-5days
Gentle PROM on days 4-28
GE AAROM 4th-8th wks
After 8th wk, gradually incr forces
What other part of the body do grade 1 sprains heal similarly to?
Tendons
What limits the healing of grade 2 & 3 sprains & why?
Synovium tears bc it limits hematoma formation & GF localization
How much weaker is a well-healed ligament?
30-50%
What enzyme limits ACL healing?
Matrix metalloproteinase
What is NSAID-use associated w/following injury?
Ligament failure
How is microfx surgery done & what are the effects
Cleans out calcifications & creates tiny fx’s in the subchondral bone
Blood & bone marrow seep out, which creates a clot that releases cartilage-building cells
How does healing of the meniscus occur?
Via chondrocyte migration
What part of the intervertebral disc has minimal healing capacity & why?
Sections that are not in direct contact w/vertebral body bc its basically avascular
How does synovium heal?
Hemmorhage, hypertrophy, & hyperplasia
What are the ways fx’s can be classified?
Trauma/Stress
Pathological
Displaced/Non-displaced
Open/Closed
Types of Fx’s
Transverse Oblique Spiral Comminuted Segmental Avulsed Impacted Torus Greenstick
Transverse Fx
Fx is at a right angle (perpendicular) to the long axis of the bone
Caused by shear forces
Oblique & Spiral Fx’s
Fx is at an angle
Result of extreme twisting forces
Comminuted Fx
Bone breaks into multiple fragments
Segmental Fx
2 fx lines
Avulsed Fx
Small piece of bone gets broken off due to an extreme force from tendon/ligament
Impacted Fx
Bone fragments get driven into each other
Torus Fx
Bone buckles into itself from axial loading
Greenstick Fx
Bone gets bent
3 Stages of Fx Healing
1) Inflammation
2) Repair
3) Remodeling
What happens during the inflammation phase of bone healing?
Bleeding–>Delivers fibroblasts, platelets, osteoprogenitor cells, cytokines & GF’s
Clotting eventually occurs–>Forms fibrous matrix
What happens during the reparative phase of bone healing?
Soft callus formation that eventually turns into a hard callus
- Osteoclasts clear necrotic bone
- Osteoblasts produce hyaline cartilage
- Primary bony spicules are formed
What GF’s are involved w/the reparative phase of bone healing?
Fibroblast GF Insulin-like GF Platelet-derived GF Transforming GF-8 Vascular Endothelial GF
How long does the reparative phase of bone healing last?
Wks 2-6/12
What happens during the remodeling phase of bone healing?
- Immature bone becomes hard lamellar bone
- Hard callus gets absorbed by osteoclasts
- Osteocytes remodel in response to WB
How long does the remodeling phase of bone healing last?
Until bone is normal strength, so months-years
Purpose of bone stimulators
Stim Ca2+ uptake & gene expression to incr mineralization
Some complications of fx’s
Malunion
Delayed Union
Nonunion
Malunion
Bone doesn’t align properly
Delayed Union
Fx takes extra long to heal
Nonunion
Bone doesn’t heal
Some risks of fx’s
ST Injury Infection-->Esp w/open fx Skin Ulceration Growth Disturbances from effected growth plates Post-traumatic arthritis Adhesions Arthrodesis Myositis Ossificans Osteomyelitis Re-fx Neuro complications Vascular compromise
