Unit 2 Muscle and Tendon Injury Flashcards
What percentage of body mass is muscle?
40-50%
what is the myotendinous junction?
common place for strain
where the muscle proper is merging with the tendon proper
what is the basal lamina?
scaffold for healing
what are satellite cells?
muscle stem cells that help with regeneration of muscle
what factors affect muscle performance under load?
age, temperature, immobilization or disuse
what are some MOIs for muscle tissue?
excess strain/stretch, excess tension, blunt force/contusion, laceration, thermal stress, myotoxic agents, disease, new exercise/activity, prolonged disuse/immobility
what are the 3 phases of muscle healing? and what phase of healing do their correlate to?
destruction (hemostasis/inflammation), repair (proliferation), remodeling (remodeling)
what is happening in the destruction phase of muscle healing?
necrosis of damaged muscle tissue
factors released, start hemostasis and inflammatory response
vascular disruption - hematoma and edema begin
leukocytes infiltrate and activation/proliferation of satellite cells (myoblasts)
what is happening during the repair phase of muscle healing?
hematoma formed
inflammatory cells arrived and satellite cells proliferation continues
new myofibers are joined
neuromuscular junction reestablished as close to the original motor point as possible
what is happening in the remodeling phase of muscle healing?
regenerated tissue matures and tensile strength increases
scar contracts and is reorganized
type 1 return to normal proportion over type 3
what causes a contusion? and what can a contusion lead to?
blunt trauma; hematoma
what are the two types of hematoma?
intermuscular and intramuscular
what is myositis ossificans?
severe contusion can result in a calcified hematoma where calcium forms in the hematoma like little pieces of bone
what are the risk factors for a strain?
inadequate flexibility, inadequate strength and endurance, muscle imbalances, insufficient warm-up or fatigue, inadequate rehab from past injury
what is a distractive strain?
excess pull, overstretch
where does most of the damage occur in a muscle strain?
at the MT junction with immediate pain
what is DOMS?
delayed onset muscle soreness due to unaccustomed exercise (especially eccentric)
metabolic products and subcellular damage
what is the effect of high force concentric contraction?
reduction in force by 10-30% lasting for hours
what is the effect of high force eccentric contractions?
reduction in force by 50-65% lasting 1-2 weeks
what tissue changes are occurring with eccentric contractions?
damage to sarcomere, disruption of ECM, intramuscular edema, increase creatinine kinase (this signals muscle breakdown)
describe the differences of the 3 grades of muscle strain.
grade 1: tear only few musculotendinous fiber, pain only with 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, at the MT junction site
why does a grade 3 muscle strain have less pain?
if the two ends are no longer connected there can’t be a force in that area that is perceived as painful
what are the clinical signs of a muscle injury?
sudden onset/traumatic
pain most pronounces during eccentric activation
localized tenderness over myotendinous junction
possible swelling and ecchymosis (due to hematoma)
AROM (sometimes PROM) of associated joint may be restricted and painful with guarding and empty end feels
resisted strength testing is weak and painful (weak due to pain)
what can you do for muscle injury management in the protective phase?
PRICEMEM, pt education
PROM, AAROM, AROM
what can you do for muscle injury management in the controlled motion phase?
AAROM, AROM, flexibility
submaximal isometrics -> multiangle submax isometrics -> multiangle max isometrics -> PREs
simple/safe balance, proprioception activities
corrective exercise of associated biomechanical deficiencies
what can you do for muscle injury management in the return to function phase?
endurance and maximizing strength, concentric -> eccentric
general return to activity - 80% strength of unaffected contralateral
speed, power, agility exercises
what is including in muscle re-injury prevention?
education on proper warm-up
holistic conditioning
maintenance of flexibility, strength
what complications can arise with the management of a muscle injury?
immobilization/disuse - less force, less tolerance to lengthening
reinjury
fibrosis
NSAIDS induce impairment in functional capacity and histology when administered at later points
muscle that is immobilized in a shortened position provides ___ force and ___ length tolerances to stretch before injury than muscle that was not immobilized.
less; shorter
what does a normal healthy tendon look like?
glistening white, with collagen fibers in tightly packed bundles (70% dry weight), parallel fibers
tendons are ___ and ___, which effects their ability to heal.
avascular and aneural
what is the difference between positional and energy storing tendons?
positional: transmit force from muscle to skeleton
energy storing: store and release elastic energy (springs usually large explosive muscles)
where are energy storing tendons loaded?
close to to failure point
what are the 3 main MOI of tendons?
loading, overuse loads, and after activity
describe the loading MOI for tendons.
sudden overload, repetitive loading, and rapid unloading
describe the overuse loads MOI for tendons.
tension + compression, shearing and friction, fascicle on fascicle, paratenon, retinacula, bone
describe the after activity MOI for tendons.
catabolism (breakdown), anabolism (build up), adequate rest between exercise bouts
when after activity does tendon catabolism occur? anabolism?
24-36 hours; 24-80 hours
describe the properties of tendon tissue.
high tensile strength (crimping on slack)
respond and adapt to loading, mechanotransduction (required for homeostasis)
low metabolic rate (O2 7.5 Xs lower than muscle tissue) which leads to very slow healing after tissue
what are the intrinsic risk factors for tendon injury?
high body weight, malalignments, imbalances, weakness, poor flexibility, poor form, gender, age
what are the extrinsic risk factors for tendon injury?
excess volume, speed, magnitude of loading
abrupt change to amount or type of load
poor environmental conditions
poor equipment
medications
prolonged immobilization
what is the incidence for types of tendon injuries? __% sports, __% industrial, __% running
30-50% sports, 42% industrial, 30% running
what are the main types of tendon injuries?
rupture, laceration, overuse (tendinopathies: tendinitis, tendinosis, tenosynovitis)
T/F: Tendons follow the same triphasic healing model that muscles do.
False.
what is the blanket term for tendon conditions arising from over use? and what causes this type of injury?
tendinopathy
cumulative trauma, weakened collagen cross-links, degraded ECM and vascular elements
what are the stages of chronic tendon injuries?
- tendinitis
- tendinosis
- complete rupture
- tendinosis with other changes such as fibrosis or calcification
what is tendinitis?
pain, swelling, dysfunction of the tendon
what does true tendon”itis” look like?
does follow the triphasic healing (lasting a year or more)
inflammatory agents are present
can be acute or chronic
peritendinitis, tenosynovitis (involves structure around the tendon)
rare
what is tendinosis?
degeneration of tendon structures
T/F: pain is not always present with tendinosis.
true
what are the 4 main histological changes that occur with tendinosis?
- angiofibroblastic hyperplasia
- disorganized and immature collagen
- vascular hyperplasia and neovascularization
- increase of neurochemicals
what does tendinosis look like?
tendon is yellow-brown or grey
thickened
disorganized fibers
partial or complete rupture
thickened paratenon
adhesion of para and epi tendon
no inflammatory cells
describe the tendinosis cycle.
increased demand is placed on the tendon, it either has adequate repair or inadequate repair. if inadequate repair there is:
a decreased collagen and matric production
tenocyte death
further decrease in collagen and matrix
increased vulnerability to injury
what are the 3 presentations of degeneration of tendon?
- excess load can lead to reactive tendinopathy which will resolve if load is modified
- if unmodified load will progress to tendon disrepair which can be brought back by load modification (tendon disrepair)
- uncheck will progress to degenerative tendinopathy
what are the clinical signs of tendon injury?
well localized pain with little referral beyond the tendon
strong but painful (unless full rupture) in proportion to resistive load
painful with stretch or palpation
pain resolves quickly when load withdrawn
unusual to be painful without load, at night or at rest (except when very reactive or associated with metabolic or seronegative condition)
what is the time to recovery for reactive/early disrepair tendon injuries?
caught early: days- 2 weeks
caught late: 4-6 weeks
what is the time to recovery for regeneration/late disrepair tendon injuries?
caught early: 6-10 weeks
caught late: 3-9 months
what is the clinical presentation of reactive/early disrepair tendon injuries?
(tendonitis)
age 15-25
rapid onset related to load; higher than previous load
swelling of tendon (3-4cm)
highly irritable with activity/exercise
painful
uncommon/rare
what is the clinical presentation of regeneration/late disrepair tendon injuries?
(tendinosis, tendinopathy)
age 40-65+
onset after overload
history of problem related to loading
variable swelling
mild-moderate irritability
painful
very common
what would be the focus of conservative therapy for reactive/early disrepair?
load modification
what would be the focus of conservative therapy for regeneration/late disrepair?
encourage collagen synthesis and strength
When loading a tendon to treat for chronic tendinopathy the way the tendon is loaded is not as important as the ___ and the ___.
timing and the amount of load.
describe the whole task perspective.
A. no strength and no motor control = undesired outcome
B. strength but no motor control = undesired outcome
C. no strength but motor control = inability to perform task
D. both strength and motor control = ability to perform task
