Introduction to muscle injury , inflammation ,exercise intervention that should be used during each stage during inflammation & repair.

1. Muscle Injury
Inflammation
Repair
Tahir Ramzan
Riphah International University

2. Introduction--- Types of injuries
• Primary Injury
– Injury from acute or chronic trauma
• Secondary Injury
– Inflammatory response to primary injury

3. 3 Phases of Tissue Healing
• Inflammatory –response phase
• Fibroblastic-repair phase
• Maturation-remodeling phase
– Healing process is a continuum and phases
overlap one another with no definitive beginning
or end points

4. Inflammatory-Response Phase
• After injury, healing process begins
immediately
– Destruction of tissue produces direct injury to
cells of various soft tissue
– Characterized by redness, swelling, tenderness
and increased temperature
– Critical to entire healing process

5. Inflammatory-Response Phase
• Leukocytes and other phagocytic cells
delivered to injured tissue
– Dispose of injury by-products through
phagocytosis

6. Inflammatory-Response Phase
• Vascular reaction
– Blood coagulation
and growth of
fibrous tissue
occurs
– First 5-10 minutes
vasoconstriction
occurs
• Best time to
evaluate
• Followed by
vasodilation
• Effusion of blood
and plasma last 24
• Chemical mediators
– Released from damaged
tissue, white blood cells
and plasma
– Histamine, leukotrienes
and cytokines assist in
limiting exudate/swelling
– Amt of swelling directly
related to extent of vessel
damage

7. Inflammatory Response Con’t
• Formation of Clot
– Platelets adhere to
collagen fibers and create
sticky matrix
• Platelets and leukocytes
adhere to matrix to form
plug
• Clot formation occurs 12
hours after injury and is
complete w/in 48 hrs
• Set stage for fibroblastic
phase
• Chronic inflammation
– Acute phase dos not
respond sufficiently to
eliminate injury agent and
restore tissue to normal
physiologic state
– Damage occurs to
connective tissue and
prolongs healing and
repair process
– Response to overuse and
overload

8. Inflammatory Response Con’t
• Entire phase last 2-4 days
– Greater tissue damage longer
inflammatory phase
– NSAIDS may inhibit inflammatory
response thus delaying healing process
• Will assist with pain and swelling

9. Fibroblastic-Repair Phase
• Proliferative and regenerative activity leads to
scar formation
– Begins w/in 1st few hours after injury and can last
as long as 4-6 weeks
– Signs and Symptoms of inflammatory phase
subside
– Increased O2 and blood flow deliver nutrients
essential for tissue regeneration

10. Fibroblastic-Repair Phase
• Break down of fibrin clot forms connective
tissue called granulation tissue
– Consist of fibroblast, collagen and capillaries
• Fills gap during healing process
– Unorganized tissue/fibers form scar
• Fibroblast synthesize extracellular matrix consisting
of protein fibers (Collagen and Elastin)
– Day 6 –7 collagen fibers are formed throughout scar
– Increase in tensile strength increases with rate of
collagen synthesis

11. Fibroblastic-Repair Phase
• Importance of Collagen
– Major structural protein that forms strong, flexible
inelastic structure
– Type I, II & III
• Type I found more in fibroblastic repair phase
• Holds connective tissue together and enables tissue
to resist mechanical forces and deformation
– Direction of orientation of collagen fibers is along lines of
tensile strength

12. Fibroblastic-Repair Phase
• Importance of Collagen
– Mechanical properties
• Elasticity
– Capability to recover normal length after elongation
• Viscoelasticity
– Allows slow return to normal length and shape after
deformation
• Plasticity
– Allows permanent change and deformation

13. Maturation-Remodeling Phase
• Long term process that involves realignment of
collagen fibers that make up scar
– Increased stress and strain causes collagen fibers to
realign to position of maximum efficiency
• Parallel to lines of tension
• Gradually assumes normal appearance and function
• Usually after 3 weeks a firm, contracted,
nonvascular scar exist
– Total maturation phase may take years to be
totally complete

14. Maturation-Remodeling Phase
• Wolf’s law
– Bone and soft tissue will respond to physical
demands placed on them
• Remodel or realign along lines of tensile force
• Critical that injured structures are exposed to
progressively increasing loads throughout rehab
process
– As remodeling phase begins aggressive active range of
motion and strengthening
– Use pain and tissue response as a guide to progression

15. Maturation-Remodeling Phase
• Controlled mobilization vs. immobilization
– Animal studies show Controlled mob. Superior to
Immobilization for scar formation
• However, some injuries may require brief period of
immob. During inflammatory phase to facilitate
healing process

16. Factors that impede healing
• Extent of injury
– Microtears vs.
macrotears
• Edema
– Increased pressure
causes separation
of tissue, inhibits
neuro-muscular
control, impedes
nutrition,
neurological
changes
• Hemorrhage
– Bleeding causes same
neg. effect as edema
• Poor vascular supply
– Tissues with poor
vascular supply heal at a
slower rate
– Failure to deliver
phagocytic cells and
fibroblasts for scar
formation

17. Factors that impede healing
• Separation of tissue
– How tissue is torn
will effect healing
• Smooth vs. jagged
• Traction on torn
tissue, separating 2
ends
– Ischemia from
spasm spasm
• Atrophy
• Corticosteroids
– In early stages
shown to inhibit
healing
• Keloids or
hypertrophic scars
• Infection
• Health, Age and
nutrition

18. Healing Process-Ligament Sprains
• Tough, relatively inelastic band of tissue that
connects bone to bone
– Stability to joint
– Provide control of one articulating bone to
another during movement
– Provide proprioceptive input or sense of joint
position through mechanoreceptors
• 3 Grades of lig. tears

19. Healing Process-Ligament Sprains
• Physiology
– Inflammatory phase-loss of blood from damaged
vessels and attraction of inflammatory cells
– During next 6 weeks-vascular proliferation with
new capillary growth and fibroblastic activity
• Immediately to 72 hours
– If extraarticular bleeding in subcutaneous space
– If intraarticular bleeping occurs in inside joint capsule

20. Healing Process-Ligament Sprains
• Essential that 2 ends of ligament be
reconnected by bridging of clot
– Collagen fibers initially random woven pattern with
little organization
– Failure to produce enough scar and of ligament to
reconnect 2 reasons ligaments fail
• Maturation
– May take 12 months to complete
– Realignment/remodeling in response to stress and
strains placed on it

21. Healing Process-Ligament Sprains
• Factors that effect healing
– Surgery or non surgical approach
• Surgery of extraarticular ligaments stronger at
first but may not last over time
• Non surgical will heal through fibrous scarring ,
but may also have some instability
– Immobilization
• Long periods of immobilization may decrease
tensile strength weakening of insertion at bone
• Minimize immobilization time
• Surrounding muscle and tendon will provide
stability through strengthening and increased
muscle tension

22. Healing Process-Cartilage
• Cartilage
– Rigid connective tissue that provides support
• Hyaline cartilage: articulating surface of bone
• Fibro cartilage: interverterbral disk and menisci.
Withstands a great deal of pressure
• Elastic cartilage: more flexible than other typesauricle of ear and larynx

23. Healing Process-Cartilage
• Physiology of healing
– Relatively limited healing capacity
• Dependant on damage to cartilage alone or
subchondral bone.
• Articular cartilage fails to elicit clot formation or
cellular response
• Subchondral bone can formulate granulation tissue
and normal collagen can form

24. Healing Process-Cartilage
• Articular cartilage repair
– Patients own cartilage can be harvested and
implanted into damages tissue to help form new
cartilage
– Promise for long term results
• Fibrocartilage/Menisci
– Depends on where damage occurs
– 3 zones of various vascularity
• Greater that blood supply better chance of healing on own

25. Healing Process-Bone
• Similar to soft tissue healing, however
regeneration capabilities somewhat limited
– Bone has additional forces such as torsion,
bending and compression not just tensile force
– After 1 week fibroblast lay down fibrous collagen
– Chondroblast cells lay down fibrocartilage creating
callus
– At first soft and firm, but becomes more firm and
rubbery
– Osteoblast proliferate and enter the callus
• Form cancellous bone and callus crystallizes into bone

26. Healing Process-Bone
• Osteoclasts reabsorb bone fragments and
clean up debris
– Process continues as osteoblast lay down new
bone and osteoclasts remove and break down
new bone
• Follow Wolfs law-forces placed on callus-changes
size, shape and structure
• Immobilization longer 3 to 8 weeks depending on
the bone

27. Healing Process-Muscle
• Similar to other soft tissue discussed
– Hemorrhage and edema followed by phagocytosis to
clean up debris
– Myoblastic cells from in the area and regenerate new
myofibrils
– Active contraction critical to regaining normal tensile
strength according to Wolff's Law
– Healing time lengthy-Longer than ligament healing
• Return to soon will lead to re-injury and become very
problematic
• 6-8 weeks?

28. Healing Process-Tendon
• Not as vascular as muscle
– Can cause problems in healing
– Fibrous union required to provide extensibility
and flexibility
• Abundance of collagen needed to achieve good
tensile strength
• Collagen synthesis can become excessive can
result in fibrosis: adhesions from in surrounding
structures
– Interfere with gliding and smooth movement
– Tensile strength not sufficient to permit strong pull for
4 to 5 weeks
» At risk of strong contraction pulling tendons ends
apart

29. Healing Process-Nerve
• Nerve cell is specialized and cannot
regenerate once nerve cell dies
– Injured peripheral nerve- nerve fiber can
regenerate if injury does not affect cell body
– Regeneration is very slow 3-4 mm /day
• Axon regeneration obstructed by scar formation
• Damaged nerve within CNS regenerate poorly
compared to peripheral nervous system
– Lack connective tissue sheath and nerve cells fail to
proliferate

30. Rehabilitation philosophy
• Choose therapeutic exercises/modalities that
facilitate healing process at specific phases
– Stimulate structural function and integrity of injured
part
– Positive influence on the inflammation and repair
process to expedite recovery of function
– Minimize early effects of inflammatory process
including pain, edema control, and reduction of
muscle spasm.
• Produce loss of joint motion and contracture
– Finally concentrate on preventing reoccurrence of
injury by assuring structural stability of injured
tissue
• Appropriate return to play guidelines