Transcript Chapter 2 - ESHE 365

2
Concepts
of Healing
Healing
By primary intention:
Wound separation is small
Bridge of cells binds ends of wound
together
Minor wounds, suture wounds
By secondary intention:
Separation is large-2nd ° Sprains
Tissue must fill space-starting at bottom
and sides of wound
More scar, longer healing time
Tissue Healing Phases
Inflammation Phase
Necessary phase
Occurs during first 3-5 days
Complex cellular and chemical
interactions take place
Neutrophils/PMN’s abound
Macrohages replace PMNs in
24-48 h to debride area
Signs of Inflammation
Redness
Temperature increase
Edema
Pain
Reduced function
Causes of Inflammation
The signs of inflammation occur because
of the increased metabolic activity and
fluid in the region and the tissue damage
that has occurred. Loss of function is
produced by the primary signs of
inflammation.
Immediate Injury Response
Proliferation Phase
Duration: 2-4 weeks
Angiogenesis and granulation tissue
formation
Increased fibroblasts by day 3-5
following injury; reduced PMNs
Type III collagen formed
By day 12, type I collagen replacing
type III
Signs of Proliferation
Redness
Swelling
Pain
Local temperature
Remodeling Phase
Lasts 6-18 months
Myofibroblasts cause wound
contraction to minimize scar
Collagen transition—type I replaces
type III
Capillaries diminish in number
Tensile strength increases
Signs of Remodeling
Reduced redness
Reduced edema
Reduced pain
No local temperature
Growth Factors
Proteins
Specific growth factors impact
specific cells
Named for target cells, source,
behavior
Perform important roles in healing
process
Roles of Growth Factors
in Healing
Control migration and proliferation
of cells
Affect fibrin-plug formation
Control phagocytization
Assist capillary endothelial
production
Stimulate type III collagen removal,
type I formation
Ligament Healing
Site fills with erythrocytes,
leukocytes, lymphocytes.
Monocytes and macrophages
infiltrate.
Fibroblasts appear, increase, produce
extracellular matrix.
Cellular and matrix structures replace
the blood clot.
Macrophages, fibroblasts diminish;
type I collagen replaces type III.
Near-normal tensile strength is
restored at week 40-50.
Tendon Healing
Wound gap filled by phagocytes
Collagen synthesis
Revascularization; synovial sheath
rebuilt
Fibroblasts revert to tenocytes; type
III collagen replaced with type I
Strength is 85-95% normal at week
40-50
Tensile strength
-maximal amount of stress or force
that a structure is able to withstand
before tissue failure occurs—in this
case, the amount of outside force that
can be applied to a muscle, tendon,
ligament, or bone before it tears or
breaks
Muscle Healing
Fragmentation of muscle fibers;
macrophages appear
Appearance of fibroblasts; reduced
muscle tension
Day 7: scar tissue; near-normal
muscle tension can be produced
Day 7-11: near-normal tensile
strength
Regenerating myotubes; crossstriated muscle fibers
Contraction ability: 90% normal at
6 weeks to 6 months
Articular Cartilage Healing
Fibrin clot is formed
Fibroblasts combine with collagen
fibers to replace clot
1 month- fibroblasts differentiate;
condrocytes appear
2 months—defect resembles
cartilage, but collagen is type I
6 months—type I and II calcified
cartilage with normal appearance
Bone Healing
PMNs, plasma, lymphocytes
Fibroblasts invade
Hematoma forms; fractured edges
become necrotic
Osteoclasts proliferate; hard callus
develops
External blood supply dominates;
then inner bone circulation
reestablished
3-4 months: Fracture is healed
Week 12: near-normal strength
restored
Tensile strength
-maximal amount of stress or force
that a structure is able to withstand
before tissue failure occurs—in this
case, the amount of outside force that
can be applied to a muscle, tendon,
ligament, or bone before it tears or
breaks
Tensile Strength During
Healing Phases
Inflammation
Rapid decline to 50%
Source of tensile strength: fibrin clot
Proliferation
Increase in tensile strength
Source of tensile strength: collagen,
granulation tissue
(continued)
Tensile Strength During
Healing Phases
Remodeling
Bone 83% of normal in 12 weeks
Ligament and tendon near normal in
17-50 weeks
Full tensile strength never regained
Healing and Tensile
Strength
For a therapeutic exercise program to be
successful, one must have respect for the
healing process and a knowledge of
tensile strength factors.
Factors That Affect
Healing
Modalities
Medications/Drugs
Other modifying factors (age,
disease, etc.)
Treatment Modalities
Ice
Electrical stimulation
Superficial heat
Deep heat
Influence of Modalities
on Healing
Relieve pain, spasm, edema
Enhance protein synthesis
Retard atrophy, facilitate muscle
activity
Improve circulation
Enhance collagen and neovascular
production
Promote fibroblast production
Factors in Medication
Effectiveness
half-life: the amount of time it takes
for the level of a drug in the
bloodstream to decrease by half
steady state of a drug: the state in
which the average level of a drug
remains constant in the blood—the
amount of drug leaving the body is
equal to the amount being absorbed
Effects of NSAIDs
on Healing
Inhibit prostaglandin production
Increase blood clotting time
Decrease the effectiveness of other
drugs
Absorption rate decreased when
NSAIDs used with antacids
Drugs That Can Delay
Healing
Antibiotics
Nicotine
Corticosteroids
Other Modifying Factors
That Can Affect Healing
Surgical technique
Age
Disease
Wound size
Infection
Nutrition
Muscle spasm
Edema
Role of Therapeutic
Exercise in Inflammation
Phase
Control edema and pain
Limit tissue stress because of
weakness of fibrin plug
Avoid strengthening activities
Role of Therapeutic
Exercise in Proliferation
Phase
Tissue is weak but improving in
strength with collagen production.
Patient can start range-of-motion and
limited strengthening activities.
Exception is in tendon repairs.
Role of Therapeutic
Exercise in Remodeling
Phase
Progressive increase in tensile
strength allows progressive increase
in stress.
Stress application must coincide with
increase in tensile strength.
Considerations
for Appropriate Course
Usual healing sequence and timing
Individual’s unique response to the
injury and treatment
Signs of an Overly
Aggressive Program
Increased pain, especially
postexercise
Increased edema, especially if lasts
more than 1 day postexercise
Diminished function from the
previous day’s treatment