Injury, inflammation, and healing Flashcards
Mechanisms of cellular injury
- ischemia
- infectious
- immune
- genetics
- nutritional
- physical
- chemical
- psychosocial
Reversible vs irreversible
- cell death (unable to adapt)
- adaptation (small damage, no injury. Acute or chronic)
- repair (scar tissue)
- regeneration
Issues that affect tissue healing
- physiological
- general health
- comorbidities
- substance use / abuse
- infection / foreign bodies
- tissue type
- medical treatment
Phases of normal healing for all tissue types
- Hemostasis and degeneration
- Inflammation
- Proliferation and migration
- Remodeling and maturation
Regeneration vs repair pic
Pic
- Hemostasis and degeneration
- immediately after injry body tries to stop bleeding via platelets, hematoma, necrosis
- abnormal: low platelets or blood thinner meds
- cytokines are released
- causes inflammation (growth factos and fibroblasts
- ** do not confuse with homeostasis
- Inflammation
- protective and curative
- replaces injured tissue
- begins with formation of blood clot (vasodilation)
- leukocytes, macrophage, and proteases
- growth factors, chemokines, and cytokines
- about 5 days: fibroblasts
- chronic disease stall the healing at this phase, failing to progress to the next phase
CSI
- erythema - pain - heat - edema - loss of function
- *abnormal presentation: pts with diabetes may not “mount” a normal inflammatory response, so these signs may not be obvious
Acute inflammation
Normal
- protective
- proteins and fluid build up
- slower in older adults
- subsides in presence of small amount of necrosis
- will heal on its own
Chronic inflammation
Pathological
- large / prolonged injury
- delays healing
- common in older adults
- occurs with larger amount of necrosis or lack of intervention
- requires skilled care
- Proliferation and migration
- starts 2 days after injury (overlaps with inflammation)
- endothelial cells proliferate to establish vascular network for O2 and nutrients (angiogenesis)
- new vessels are leaky (edema)
- fibroblasts synthesize collagen
- lasts for several weeks
- healing can also stall at this phase, due to poor control of a comorbity
- abnormal form: hypergranulation
- Remodeling and maturation
- scar tissue reduced and remodeled
- reorientation of collagen and strength regained
- mature scar 3-4 months
- lasts for 1-2 years
- abnormal form: keloid formation (different than hypergranulation)
Healing timeline pic
Pic
Muscle injury etiology
Contusion (blunt force) - laceration (open wound) - strain - sprain
Strain
An injury to a muscle, typically occurring at the myoteninous junction
- overstraining of the myofibrils likely during eccentric contraction
- may have signification bleeding
- etiology: a tensil, mechanical stress / trauma
Grades of strains
I: Minor discomfort and swelling, few torn muscle fibers, minimal loss of strength and movement
II: moderate to sever pain, pain with muscle contraction that limits activity, measurable loss of strength
III: severe pain, complete rupture of muscle belly or muscle tendon complex (mm pull or tear), severe loss of función
Muscle healing phases
- hematoma formation and inflammation overlap (24-48 hrs)
- phagocytosis (6-8 weeks)
- remodeling: muscle regeneration reorganization of scar tissue takes up to 1 year!
- 1/3 injuries re-occurs within 1 year
Treatment strains pic
Pic
Treatment considerations
- Inflammatory response depends on extent of damage and degree of vascularization
- Active contraction prior to 3 weeks s/p injry can cause further damage
- Passive ROM: no increase in tensile strength of tendon/muscle
- Mechanical stress of tendons / mm stimulates repair and functional remodeling
- Low intensity pulsed ultrasound
- Kinesiotaping
Mm stiffness
Causes
- microfibrinous adhesions
- increased collagen fibers
- electrolyte changes
- release of mm enzymes
Sprains
Injury to a ligament
- etiology: the ligament is mechanically stressed
- 80-85% of ankle sprains inversion, AFTL, calcaneal fibular, PTFL
Grades of sprains
I: Minimal pain and no significant instability
II: severe pain, minimal-moderate joint instability but definite joint end feel, and partial tear of ligs
III: severe pain during injury with less pain after, very unstable joint—no joint end feel, and ligament has been completely torn
Treatment sprains pic
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Ligament treatment considerations
- healed lig will be 30-50% weaker in tensile strength than before injury
- treatments that stabilize th joint put lig i optimal length and position can reduce scarring
- early controlled mobilization and loading lig can promote healing and improve post-injury tensile strength
- proprioception is slower than strength to return, which contributes to reinjury
Immobilization
Aid early healing and repair/protection from further injury
- decreased force generation ability (muscle
- decreased tensile strength (ligs and tendons)
Mobilization (with pain-free tolerance)
- earlier return to force generation (muscle)
- mm fibers reorient in functional patterns
- decreased scar tissue formation
- earlier gains in tensile strength (ligs and tendon)
- collagen fibers orient along lines of stress
Cartilage
4 types:
- articular - fibrocartilage - elastic - fibroelastic
Healing challenges
- avasular - aneural - alymphatic
Compact bone
Dense, composed of concentric rings
Spongy bone
Composed of small needle like or flat pieces of bone (trabeculae)
Trabeculae
Form an open network which is filled with bone marrow
Signs
Objective/measureable
- visual/palpable change in anatomy (deformity)
- radiographic changes
- inflammation
- crepitus (noise)
Symptoms
Subjective
- severe, persistent pain
- point tenderness
- inability to bear weight (because they feel it)
Types of fractures
- Open vs closed
- Complete vs incomplete
- Simple vs comminuted
- Compression fracture of spine
- Impacted
- Pathological
- Stress
- Epiphyseal
- Avulsion
Open vs closed fracture
Open
- results when the skin is broken and the bone is exposed
- very high risk of infection
- total disruption of the bone
Closed
- the bone is broken, but the skin remains intact
Complete vs incomplete fracture
Complete
- the bone fragments are separated completely
- the bone is broken to form 2+ pieces
Incomplete
- the bone is only partially broken
- the bone fragments are still partially joined
- greenstick fracture
Simple vs comminuted fracture
Simple: a single break in the bone. Bone ends maintain their alignment and position
Comminuted: multiple fracture lines and bone fragments
Compression fracture
- common in the vertebrae
- occurs when a bone is crushed
- common with osteoporosis
- results in significant pain and disability
Impacted fracture
- similar to a compression fracture
- one end of the bone is forced into the adjacent bone
- closed fracture
- common in car accidents and falls
- the neck of the femur is crushed against the pelvis
Pathological fracture
- results from weakness in bone structure due to conditions such as a tumor, hormonal imbalance, or osteoporosis
- the break occurs spontaneously or with very little stress on the bone
Stress fracture
- results from repeated, excessive stress
- common overuse injury, most often seen in athletes who run and jump on hard surfaces
- common in the tibia, femur, and metatarsals
Epiphyseal fracture
If the plate is separated from the epiphysis or diaphysis without proper treatment, growth will not be normal
Epiphyseal pic
Pic
Avulsion fracture
- fragment of bone at the insertion of a muscle, tendon, or ligament becomes detached as a result of excessive tension
- piece of bone is pulled free (usually occurs near the joint line)
Classification by direction of fracture line
- Transverse
- Linear
- Oblique
- Spiral
Transverse fracture
Fracture is at the right angle to the bone’s long axis
Linear fracture
Fracture is parallel to the bone’s long axis
Oblique fracture
- the fracture is at an angle to the diaphysis of the bone
- the fragments tend to override as a result of muscle contraction, unless stability is maintained by fixation
Spiral fracture
- a break that angles around the bone
- usually due to a twisting injury
- usually requires fixation
- Hematoma phase of bone healing
Fracture, blood clot, fibrin, and platelets
- Inflammation phase of bone healing
Lasts 24-48 hrs to 2 weeks
- vasoactive (heat, redness, swelling, pain)
- fibrin meshwork, fibroblasts
- phagocyte cells to area of inflammation to remove hematoma
- chondroblasts brought to the site of injury
- Reparative phase
- soft callus formation 2 weeks
- soft callus replaced by hard callus 6-12 weeks
- fracture is not stable at end of this phase
- Bone remodeling
- bone restructures itself over a period of 1 year, medullary canal is restored
- callus is reabsorbed and the anatomical contour of the bone is regained
- wolff’s law: the bone forms and remodels in the direction of forces (mechanical stresses acting on it)
- from disorganized to mature organized bone tissue
Fracture management
Fragment reduction: re-alignment fragments
- maintenance of alignment: stabilize, immobilize, ORIF, OREF, traction, non-weight bearing
- preservation and restoration of function: AROM exercises for the rest of the body and strengthening exercises
ORIF
Open reduction internal fixation
- surgical repair of fracture
- use of pins, plates and/or rods to position bones in anatomical alignment
OREF
Open reduction external fixation
- painful af
- high risk of infection
Complications during fracture healing
- Infections
- Ischemia
- Nerve damage
- Slowed healing
- DM - elderly - poor circulation - nutritional deficits - medication such a glucocorticoids
Delayed union
Factors that could cause a delayed union are poor health, poor circulation, and infection
Non-union
A fracture that does not heal. Causes may include poor health, poor circulation, infection and I fracture mismanagement
Mal-union
The fracture heals in a an acceptable position and could cause a significant impairment
Therapy considerations
Preservation and restoration of funciton
- AROM exercises for rest of body
- strengthening exercises
- we do not treat the fracture
- immobilization is bad!
