Musculotendinous tissues Flashcards
How are MSK injuries usually caused?
mechanical forces that cause direct trauma, compression, friction, or repeated over-stretching
What else is damaged with an MSK injury?
- connective tissue
- blood vessels
- nerves
What are the 4 phases of healing?
- hemostasis
- inflammation
- proliferation
- remodeling
What is primary healing vs secondary healing?
Primary:
- healing that occurs because of the injury itself
Secondary:
- response to the healing that is done by the healing process via inflammation
What does hemostasis include?
Stops the bleeding
Includes:
- vasoconstriction
- clot formation
- cells drawn to area via growth factors (fibroblasts)
0-6/8 hours
What is the difference between highly vascular vs less vascular structures when it comes to bleeding?
Highly vascular bleeds longer than those that are less vascular
What does the inflammatory phase do and what does it include?
Cleans up wound site
Stimulated by chemical mediators of the bleeding stage
Main mediators:
- histamine
- bradykinin
- prostaglandins
What is the inflammatory resolution?
Neutrophil apoptosis -> macrophages gobble up dying cells -> macrophages switch jobs and secrete cytokines and help regen tissue
What are the clinical signs during the inflammatory phase?
- redness, swelling, heat
- loss of function
- pain at rest or w/ active movement
- potential muscle guarding
- pain w/ passive movement before tissue resistance
What is the main management in the acute phase of an injury?
Protective phase
- control pain, edema, and inflammation
- restore full ROM, prevent atrophy, maintain soft tissue integrity
- enhance function
Use PRICEMEM
What does PRICEMEM stand for?
- protection
- rest
- ice
- compression
- elevation
- manual therapy
- early motion
- medications
What does the proliferation phase do and how long does it last?
4-22 days (Peak at 2-3 weeks)
Rebuilds damaged structures and strengthens wound
What marks the peak of the proliferation phase?
2-3 weeks after injury when bulk of scar material is formed
What are 2 ways tissue is grown?
1) regeneration: regrowth of original tissue
2) Repair: formation of scar tissue (connective tissue)
What are the processes that take place in the proliferation phase?
- Epithelialization (reestablishes the epidermis)
- Collagen production (type III -> type I)
- Wound contraction
- Neovascularization (angiogenesis)
What are the clinical signs during the proliferative phase? Lets you know you are IN the proliferation phase
1) decrease in pain
2) erythema resolved
3) no active effusion (could have residual swelling)
4) increase in pain-free AROM/PROM
5) pain is present w/ passive movements at point of tissue resistance
What is the management like during the proliferation phase?
Controlled motion phase of rehab
GOAL: create a strong extensible scar
- protect forming collagen
- direct collagen orientation
- prevent cross-linking & scar contracture
- modify faulty joint mechanics
What are the intervention approaches during the proliferation phase of rehab?
- educate patients about s/s of overstressing healing tissue
- transition from passive interventions toward progressive stress of tissue
What is the mechanism that helps tissues heal through loading?
mechanotransduction
What is the 3-step process in mechanotransduction?
1) mechanocoupling: mechanical trigger
2) cell to cell communication: distribution of the message
3) effector cell response: tissue factory that produces & assembles
How long is the remodeling phase and what does it do?
few days to 2 years
modifies scar tissue into mature form
What is included in the remodeling phase of healing?
Process of collagen turnover: reabsorption and deposition
- fibroblast synthesize, deposit, and remodel ECM
new collagen is thicker, stronger, and more organized
Will scar tissue be back to normal strength?
NO
- in 3 weeks = 30% strength
- in 3 months = 80% strength
will NEVER be 100% again
What are the clinical signs during the remodeling phase? lets you know you are in the remodeling phase
1) progressed to pain-free function & activity
2) pain is felt at end range of PROM AFTER tissue resistance is met
What is management like in the remodeling phase?
Return to function phase
GOAL: restore big picture movement related to activity
- progressive increase speed and neuromuscular control
What are some causes and contributing factors to chronic inflammation?
- overuse, repetitive strain, and cumulative trauma
- trauma with subsequent microtrauma
- scarring
- imbalance between length and strength of muscles
- muscle weakness
- excessive repeated eccentric demand
What are some local factors affecting healing?
- type, location, size of injury
- infection
- vascular supply
- movement (early vs late)
What are some systemic factors affecting healing?
- age
- disease (diabetes, autoimmune)
- medications
- nutrition
- hormones
Which tissues have the lowest to the highest healing potential?
- cartilage
- meniscus/disc
- ligament
- tendon
- bone
- muscle
What is the basal lamina?
- scaffold in the muscle for healing
What are satellite cells in muscle?
- muscle stem cells
What are some properties of muscle tissue?
- makes body mobile and gives stability
- viscoelastic properties (creep, stress, strain)
What are some factors that affect muscle performance under load?
- age
- temperature
- immobilization
What is the difference between a strain and a sprain?
- strain = muscle
- sprain = ligament
What are some MOIs of muscles?
- excess strain/stretch
- excess tension
- blunt force/contusion
- laceration
- disease
- prolonged disuse
What are the muscle phases of healing?
Destruction -> Repair -> Remodeling
What is included in the destruction phase of muscle healing?
- necrosis of damaged muscle tissue
- factors released and hemostasis/inflammation response
- hematoma & edema begin
- leukocytes activate satellite cells
What is included in the repair phase of muscle healing?
- hematoma formed
- inflammatory cells arrive and satellite cells continue proliferation
- new myofibers form
- neuromuscular junction reestablished (as best as possible)
What is included in the remodeling phase of muscle healing?
- regenerated tissue matures and tensile strength increases
- scar contracts and reorganized
- type III -> type I ratio improved
What are different ways a contusion can form?
- blunt trauma
- myositis ossificans (calcified hematoma)
- hematoma (inter OR intramuscular)
Where does most of the damage occur during a muscle strain?
at the musculotendinous junction
What happens to the concentric force of a muscle after a strain?
- force reduction of 10-30% which lasts for hours
What happens to the eccentric force of a muscle after a strain?
- force reduction of 50-60% which lasts for 1-2 weeks
What type of tissue changes occur with a muscle strain that occurs during a concentric/eccentric muscle contraction?
Concentric:
- NO damaging effects
Eccentric:
- damage to sarcomere
- disrupts extracellular matrix
- intramuscular edema
- increase in creatinine kinase
What classifies a grade 1, 2, or 3 degree strain?
Grade 1:
- only few musculotendinous fibers torn
- pain only w/ limited swelling
- no loss of function
Grade 2:
- disruption of moderate number of fibers
- increased pain
- some loss of strength and function
Grade 3:
- complete rupture of some musculotendinous units
- loss of function with little pain
- MT junction site
- less pain
What are some clinical signs of muscle injury?
- sudden onset of trauma
- pain during ecc activation
- localized tenderness over MT junction
- weak/painful w/ strength testing
- possible swelling or ecchymosis
What is the best course of management of a strain in the protective phase?
0-2 wks
- PRICEMEM
- PROM, AAROM, AROM
What is the best course of management of a strain in the controlled motion phase?
2-4 wks
- AAROM, AROM, flexibility
- submax isos -> multiangle submax isos -> multiangle max isos
- propriception/balance activities
- corrective exercise of biomechanical deficiencies
What is the best course of management of a strain in the return to function phase?
4-6 wks
- endurance/strength concentric -> eccentric
- general return to activity
- speed, power, agility exercises
What do tendons look like and what are they made of?
- glistening white
- collagen fibers tightly packed into bundles with elastin (2%)
- ECM is made of proteoglycans and GAGs
- avascular and aneural
Where do tendons get their nutrients from?
- osteotendinous junction and myotendinous junction
What are some of tendons properties?
- transmit force from muscle to skeleton
- store and release elastic energy
- high tensile strength
- responds to adaptive loading (mechanotransduction is required for homeostasis)
- VERY slow healing after injury
How do tendon injuries occur?
Loading:
- suddenly
- repetitively
- rapid unloading
Overuse loads:
- tension + compression
- shearing + friction
- fascicle on fascicle
What are some intrinsic factors for tendon injury?
- high body weight
- malalignments, imbalances, weakness
- gender
- age
What are some extrinisc factors for tendon injury?
- excess volume, speed, magnitude of loading
- abrupt change to amount or type of load
- poor equipment
- medications
- prolonged immobilization
What are common types of injuries in tendons?
- rupture
- laceration
- overuse (tendinopathies)
What is tendinopathy and how does it occur?
Blanket term for tendon conditions arising from overuse
1) cumulative trauma
2) weakened collagen cross-links
3) degraded ECM and vascular elements
What are the 4 overlapping stages of chronic tendon injuries?
1) tendinitis
2) tendinosis
3) complete rupture
4) tendinosis w/ other changes (fibrosis or calcification)
What is the difference between tendinitis and tendinosis?
Tendinitis:
- pain, swelling, dysfunction of tendon
- tendon is inflamed
Tendinosis:
- degeneration of tendon structures
- pain is not always present
What are the 4 main histological changes involved with tendinosis?
- angiofibroblastic hyperplasia
- disorganized + immature collagen
- hypercellularity + increased ground substance
- increase of neurochemicals
What are some indicators of tendinosis?
- thickened
- yellow-brown or grey tendon
- partial/complete rupture
- disorganized
- adhesion of para- & epi- tendon
What are some clinical signs of tendon injury?
- well localized w/ little referral beyond tendon
- strong but painful response to load
- pain w/ stretch or palpation
- pain resolves quickly when load is withdrawn
What are good ways to manage reactive/early disrepair phase of a tendon?
- relative rest and education
- anti-inflammatory modalities
- address kinetic chain
- rest between sessions
- NSAIDs
What are good ways to manage late disrepair/regeneration phase of a tendon?
Encourage collagen synthesis
- Ecc and conc exercise
- static stretching
- address kinetic chain
- cross friction massage
- rest between sessions
