Tissue Healing-2nd half Flashcards
Tissue Healing of PPT
Tissue adaptation
- Bones, cartilage, ligaments, muscles and tendons all adapt their appearance and composition to match functional demands
- Demands are usually mechanical and can change with immobilization, inactivity or training
If therapists know the functional demands and the tissue’s responses then…? (Tissue adaptation)
therapists can manipulate the functional demands on structures during rehabilitation to optimize tissue structure and function
Stages of healing-general
-Injury can be mechanical or chemical
-Stages the same and they overlap
>After tissues are injured, whether by an acute injury or by repetitive stress, the body responses by removing damaged tissues and replacing them with healthy ones
Inflammation stage
repair is characterized by removing tissue debris and pathogens from the injured area. Lasts 2-3 days or longer
Proliferation phase
characterized by an influx of new cells, development of granulation tissue and revascularization. Overlaps acute inflammation, usually begins three days after injury
Remodeling stage
collagen laid down haphazardly is remodeled - replaced and removed. Persists for months
What are the 5 cardinal signs of inflammation? (ON TEST)
Redness Swelling Pain Heat Loss of Function
Swelling (inflammation)
hydrostatic and osmotic pressure changes draw more fluid out of the cells
Redness and Heat (inflammation)
increased blood flow to area – histamine and vasodilators
Pain (inflammation)
-original trauma can stimulate pain receptors in injured area – If capillaries are damaged, the blood supply to tissues distal to the injury site will be decreased = ischemia = pain
Why is it common to immobilize an injured area? (inflammation)
to allow healing and to prevent further trauma
-Can be immobilized with external support or by muscle guarding
Effects of Immobilization
- The effects of prolonged immobilization can be devastating
- The proper use of exercise during the early stages of rehabilitation can speed up healing
- Not exercising can create disability
- Reversibility of these changes appears to depend on the length of immobilization
Effects of Immobilization-
BONE
Weakened, decreased collagen and mineral content
Effects of Immobilization-
CAPSULE
Shrinking, increased resistance to movement-stiffer
Effects of Immobilization-
LIGAMENT
Decreased cross-links in collagen, decreased tensile strength
Effects of Immobilization-
SYNOVIUM
- Adhesion formation
- Fibrofatty tissue proliferation into joint space
Effects of Immobilization-
TENDON
Decreased cross links in collagen disorganization of collagen fibrils, decreased tensile strength
Effects of Immobilization-MUSCLE
Loss of sarcomeres in series, decreased contractile proteins (shorter , less force production)
Effects of Immobilization- CARTILAGE
Swelling, softer and weaker
Immobilization- time for adaptation to occur?
-Fairly rapid
-Ligaments and tendons show 50% decrease in tensile strength and stiffness after 8 weeks of immobilization
-Recovery can take 12- 18 months
>Gradual reloading is necessary to restore tendon and ligament strength
What is a ligament injury called?
Sprain
-classified according to degree of damage (grades)
What is the most common grades for sprains?
grades 1-2
only 15% of all knee ligament sprains are grade 3
Sprain- Grade 1
IMPORTANT
- Microscopic tear, no joint laxity or clinical instability
- No surgical intervention needed
Sprain- Grade 2
IMPORTANT
-Tearing of some fibers, moderate laxity (5-10 mm)
-Clinical instability noted – may or may not need surgical intervention
>Determined by functional abilities and demands
Sprain-Grade 3
IMPORTANT
-Near complete or complete rupture
-Profound laxity, unstable ( greater than 10 mm)
>Most likely will need surgical repair
What are the three key conditions for ligaments to properly heal?
- Torn ligament ends must be in contact with each other
* reason we need to get edema decreased - Progressive, controlled stress must be applied to healing tissues to orient scar tissue formation
- The ligament must be protected against excessive forces during the remodeling phase
Ligament healing is related to…?
blood supply, degree of injury, and mechanical stresses applied to the ligament
Do all ligaments heal the same?
no, they do not heal at the same rate or to the same degree
1 year after injury, what is the estimated ligament-tensile strength?
only 50% to 70% of it’s original strength
How do ligaments heal?
-Ligaments can be repaired surgically or allowed to heal without surgery, depending on the degree of injury and involvement of supporting tissues
-Non surgical ligaments heal by way of scar tissue proliferation rather than true ligament regeneration
>Biomechanically inferior, possessing a large portion of type 3 immature collagen, and may not healed even at 12 months after injury
Where do muscle disorders occur?
within the contractile unit
>Consists of the muscle belly, the musculotendinous junction , the tendon and the tendon’s bony attachment
-Healing time fairly fast secondary to vascular supply
What is an injury to the muscle called?
Strain
- it will occur at weakest link of the muscle tendon unit
- Patient will report a tearing or pulling sensation or less commonly a snap
Strain- Grade 1
IMPORTANT
less than 50 % damage
-Small amount of mechanical injury to the tissue, irritation and inflammation but no structural damage; mild injury results in overstretching or tearing small amount of muscle or tendon fibers
Strain- Grade 2
IMPORTANT
more than 50% damage
-Some portion of the contractile unit is damaged and some degree of functional loss is present but the entire unit is intact – moderate injury
Strain- Grade 3
IMPORTANT
complete tear
-There is loss of function of the muscle, the tendon or the tendon’s attachment due to a complete tear
»_space;Complete rupture can be in muscle belly or where tendon inserts; can have avulsion
How long does it take for a tendon to heal?
Process lengthy - up to 6 months
-Ultimate tensile strength of damaged tendon may be reduced by as much as 30% permanently
What does protected motion with tendon healing provide?
greater tensile strength, less adhesion formation, and earlier organization, orientation, and remodeling of collagen
Should there be a moderate degree of motion after tendon injury and repair? (controversy regarding early motion)
No, motion should be slight and with protection from excessive stress, if not it could be detrimental to healing
Joint capsule sprains are the result of what?
overstress that damages the fibers or their attachments
What happens to the joint capsule after injury?
it thickens and becomes more fibrous
-Excessive thickening can lead to impaired mobility
What type of collagen does articular cartilage mainly contain?
90-95% type 2
>Small cellular component with large extracellular matrix which contains a greater amount of interfibrillar material than tendons or ligaments
-Requires physiologic stress to maintain its characteristics as a strong, tough, fatigue resistant, permeable, frictionless tissue
Articular cartilage degeneration is generally characterized by which 3 progressive overlapping degenerative events?
- Hyaline cartilage begins to fray or fibrillate
- Progressive destruction leads to blistering of the articular surface
- Further joint deterioration leads to splitting or fissuring of the surface which affects the deeper layers of cartilage and eventually progresses to denuded bone
What happens with superficial lesion healing of articular cartilage?
doesn’t stimulate inflammatory reaction; the thickness of the cartilage creates barrier between fibrin, fibroblasts and inflam response cells therefore can not get there to promote healing
What happens with deep lesion healing of articular cartilage?
stimulates inflammatory response
- heal better but quality of scar within the defect is inferior to normal articular cartilage and healed scar doesn’t maintain its’ integrity over time
- low success rate, creates a thick fibrocartilagenous scar
Articular cartilage- injury
if damaged can not repair itself, will have limited mechanisms for repair
can withstand great amount of pressure/tension
Meniscus Cartilage Healing
-Dependent on injury location
-Can heal
>Very slow and fragile
- Red on white zone may heal with time, possible surgical intervention
- White zone= won’t heal, arthritic over time and might need a meniscectomy (removal)
What part of the meniscus is vascular?
the outer 1/3 (red)
What part of the meniscus is non-vascular?
inner 2/3 non-vascular (white)
What happens of part of the meniscus cartilage is removed?
it will be replaced by scar formation to mimic the meniscus
How does the synovial membrane respond to stress?
by healing with a thickening of the membrane
- Fibrosis
- Can alter the quality of the synovial fluid produced
-Joint may feel tight
Synovitis results from what?
trauma or irritation
-Joint may feel tight
How long does it take for healing of the synovial membrane?
-Typically 1-4 days for healing
4 weeks= Should be complete
If persists past 8 weeks= may indicate chronic synovitis, possible surgical intervention needed
How common is an injury to synovial fluid?
not at all, it is rare.
But…
- It can become infected if foreign agent introduced
-Changes will follow membrane injury
What’s involved with fracture management? (3)
Reduction
Maintain Alignment
Preserve and Restore function
Bone Reduction
fracture management
Approximation of bone fragments; anatomic alignment
Maintain Alignment (fracture management)
Secure fragments – overtime proper anatomic alignment promotes healing
Preserve and Restore Function
fracture management
Regain lost mobility, increase strength and function, restore balance and coordination, teach proper gait mechanics
How long does it take bone/fractures to heal?
6-8 weeks, may take up to 12
-depends on blood supply, can have avascular necrosis
Bone Classification
- Location on bone (shaft, diaphysis, epiphysis)
- Extent (complete, incomplete)
- Direction (transverse, spiral)
- Relationship (displaced, non-displaced)
- Open/compound vs. closed
Salter-Harris Fractures
Fracture classification involving the physis
Pathologic Fractures
Tumors, osteoporosis, repetitive micro-trauma
