Unit 2 Phases of Healing Flashcards
what are the four phases of healing?
hemostasis, inflammation, proliferation, and remodeling
how do MSK injuries usually occur?
typically with a mechanical force.
direct trauma, compression, friction, repeated over-stretching
The response to injury occurs ___ and ___.
sequentially and simultaneously
why is it important to understand the phases of healing?
to make sound judgement in pt care and know the appropriate timing for interventions
optimize function in long term
what is primary healing?
occurring due to the injury/insult to the tissue itself
what is secondary healing?
response to the damage that is done by the healing process (inflammation)
T/F: the healing phases do not overlap.
false. there is a substantial amount of overlap
When discussing MSK injuries which pathway from the inflammatory phase do we follow? CNS or Non-CNS?
Non-CNS
what is the length of hemostasis?
0 to up to 6-8 hours. occurs immediately after the injury if bleeding occurs until bleeding stops
what is the purpose of the hemostasis phase?
stop the bleeding
Describe the cellular and vascular cascade.
- local vasoconstriction
- clot formation via simulation of platelets and formation of fibrin
- cells (fibroblasts) drawn to the area by growth factors to repair ECM
what is the length of the inflammatory phase?
0 hours to up to 2 weeks. begins at the point of injury as soon as chemical mediators start to move.
when does the inflammatory phase peak?
2-3 hours
what is the purpose of the inflammatory phase?
clean up the wound site and prepare for construction
what are the prominent inflammatory mediators?
histamine, bradykinin, serotonin, lymphokines, prostaglandins, leukotrienes, arachidonic acid
what is the difference between cytoprotective prostaglandins and inflammatory prostaglandins?
cytoprotective: activated by COX-1. normal homeostatic needed for normal body function
inflammatory: activated by COX-2. with injury. start of the inflammatory response
what inhibits COX-1 and COX-2 from activating prostaglandins?
both: non-selective NSAIDS and Aspirin
COX-2: selective NSAIDS
what is the inflammatory response? what is occuring?
chemical mediators (PGS, histamine, leukotrienes and kinins) cause vasodilation of local blood vessels and inc’d cap permeability which allows intravascular fluid, protein, and cellular components into extravascular space (leads to edema) and circulating cells and chemical mediators to the injured tissue
what is diapedesis?
when circulating cells and chemical mediators squeeze through gaps in the capillary walls to get where they need to go (injured tissue)
what is chemotaxis?
when circulating cells and chemical mediators are signaled by chemical agents in the area of the injured tissue
what do cells like neutrophils, macrophages, lymphocytes and mast cells do during the inflammatory response? and what are the two ways?
remove/eliminate injurious stimulus.
1. enzymes/toxic substances kill, inactivate and degrade microbial agents or necrotic tissue
2. phagocytosis (clean up work, taking up dead cells) and release of growth factor (neutro and macro)
what are the clinical signs of the inflammatory response?
redness (rubor), increased temp (calor), swelling (tumor), pain (dolor) and function loss (functio laesa)
potential for muscle guarding, self-splinting, protective posturing.
with passive movement pain is reported before tissue resistance is reached (empty end feel)
The inflammatory phase continues until it resolves. what is the resolution of the inflammatory phase?
- neutrophil apoptosis (die), as they die they trigger more inflammation and more WBC influx
- macrophages gobble up dying cells and stop the noxious stuff leaking from them
- macrophages then switch jobs and secrete an anti-inflammatory cytokine and suppress the release of pro-inflammatory mediators. they help regenerate tissue, or they leave.
how no NSAIDS affect the inflammatory phase?
can delay or hamper healing in MSK tissues including muscle, tendons, cartilage, and bone. inflammation is a necessary step for healing and transition to proliferation
how can repetitive or forceful tasks affect the inflammatory phase?
can cause the acute inflammatory stage to continue, followed by fibrotic and structural tissue changes (possibly CNS reorganization resulting in movement disorders)
which phases does the acute stage consist of?
hemostasis and inflammatory phases
what should be done during the protective (acute) phase of rehab?
control pain, edema, and inflammation
restore full PROM, prevent atrophy, maintain soft tissue joint integrity, and enhance function
what is PRICEMEM and when should it be used?
protection, rest, ice, compression, elevation, manual therapy, early motion, medications
during the acute phase
Edema can lead to atherogenic muscle inhibition, what is this?
selling tells the muscles around the joint to shut off causing atrophy of the muscles
what is the length of the proliferative phase/?
4-22 days
when does the proliferative phase hit its peak? what occurs at its peak?
2-3 weeks
the bulk of the scar material is formed
what is the purpose of the proliferative phase?
to rebuild damaged structures and strengthen the wound
when needs to happen in order for the proliferative phase (construction) to begin?
phagocytes need to clear the area
what are the 2 ways that tissue can heal during the proliferative phase?
- regeneration: regrowth of the original tissue
- repair: formation of a CT scar
how does the proliferation of fibroblasts occur?
- fibroblasts are drawn in by platelets, macrophages, and other fibroblasts by growth factors and cytokines
- the fibroblasts lay down collagen and produce ECM
what are the 4 simultaneous processes of the proliferation phase?
- epithelialization: reestablishment of the epidermis
- collagen production (initially type 3 with limited tensile strength then overtime replaced with type 1 which has more tensile strength)
- wound contraction (if uncontrolled = contracture)
- neovascularization: new blood vessels form within 4 days
what are the clinical signs of the proliferative phase?
decrease in pain, erythema (redness) resolved, no active effusion (residual swelling may persist), increase in pain-free active and passive ROM (with passive movements, pain if felt at the point of tissue resistance/end range)
which phase is the controlled motion phase of rehab?
proliferative phase
what is the criteria for advancement in the proliferative phase?
pain control, adequate healing, near normal ROM, tolerance of increased strengthening
what is the intervention goal within the proliferative phase?
create a strong extensible scar by protecting the forming collagen, directing collagen orientation to be parallel to the lines of force it must withstand (by introducing force), preventing cross linking and scar contracture, and modifying faulty joint mechanics
what intervention approaches should you use in the proliferative phase?
educate pts about signs/symptoms of overstress of healing tissues
transition from passive interventions towards progressive stress of tissue through therapeutic exercise progression
what is mechanotransduction?
the process where our MSK tissue converts mechanical load into cellular response to build up the tissues
what are the 3 steps of mechanotransduction?
- mechanocoupling: mechanical trigger or catalyst
- cell to cell communication: distribution of the message
- effector cell response: the tissue factory that produces and assembles
what are the steps of therapeutic exercise progression in order of lowest amount of stress to highest amount of stress?
- submaximal isometrics
- small arc submaximal concentric/eccentric pain-free ROM
- full ROM submaximal concentric
- full ROM submaximal eccentric
- functional/activity-specific plane submaximal concentric
- functional ROM submaximal eccentric
- OKC and CKC exercises concentrically then eccentrically
- full ROM submaximal concentric isokinetic
- full ROM submaximal eccentric isokinetic
- function ROM submaximal eccentric isokinetic
what is the length of the remodeling phase?
few days to 2 years
starts in the middle-end of the proliferative phase and goes on for 1-2 years
what is the purpose of the remodeling phase?
modify the scar tissue into its mature form
what is occurring during the remodeling phase?
changes is size, form, and strength of the scar through the process of collagen turnover
1. fibroblasts synthesize, deposit and remodel the ECM
2. myofibroblasts pull wound edges together to contract the wound
3. new collagen is laid down that is thicker, stronger and more organized
what is collagen turnover?
the reabsorption of collagen that is not strong or laid down in bad organization and the deposition of new collagen that is stronger and put down properly
At 3 weeks __% of tissue strength is returned. at 3 months __% of tissue strength is returned.
30%; 80%
never 100%
what are the clinical signs of the remodeling phase?
progression to pain-free function and activity
pain is felt at the end range of passive movement after tissue resistance is met
which phase is considered the return to function phase?
the remodeling phase
what are the stages of management of the remodeling phase?
- gradual return to full and pain-free range
- progressive increase of speed and neuromuscular control
- work-related/sport-specific movements
a continued application of controlled stresses throughout
what can manual therapy be used for during the remodeling phase?
to increase joint motion and soft tissue extensibility
what is the failure to achieve healing through the natural phases?
chronic inflammation
how do you manage chronic inflammation?
address symptoms and discover the root cause
what are the local factors affecting healing?
type, size and location of injury (biggest factors)
infection, vascular supply, external forces (thermal agents, electromagnetic, mechanical pressure), movement (too early or too late)
what are the systemic factors affecting healing?
age, disease or infection, medications, nutrition, hormones, fever, oxygen
list the tissue in order from least blood supply to most blood supply.
cartilage
meniscus/disc
ligament
tendon
bone
muscle
which phases does the subacute stage of healing consist of?
proliferation phase
which phases does the chronic stage of healing consist of?
remodeling phase
how long is the acute phase?
7-10 days
how long is the subacute phase?
10 days - 6 weeks
how long is the chronic phase?
6 weeks- months
