Quiz 3 Flashcards
skeleton and tendons
what are the functions of the skeletal system?
support, protection, storage, assist motion, homeostasis, and hemopoiesis
what is hemopoiesis?
blood production
what is the diaphysis?
the bone shaft; main portion
what is the epiphysis?
distal and proximal end of long bones
what is the metaphysis?
where epiphysis and diaphysis join
where is the epiphyseal line?
in the metaphysis
what is articular cartilage?
cartilage that covers the epiphysis at articulations
what is the periosteum?
dense irregular CT that protects, nourishes, and allows growth
where is the attachment site for tendons and ligaments?
the periosteum
what is the medullary cavity?
the area within the diaphysis that contains the marrow for hemopoeisis
what is the center for hemopoeisis?
the medullary cavity
what is the endosteum?
lines the medullary cavity w/bone forming cells
what are the influences on healthy bone?
diet, hormones, and biomechanics
what is the bone matrix?
organic material and fluid
what are the benefits of increased mineral density of bones?
ability to withstand more stress
stiffness
mineral storage system
bone is a _____ _______ material
biphasic, composite
if a load is applied quickly, there is _____ stress, _____ strain
high, low
if a low force is applied over a long time, what may occur?
spurring
a low load applied will result in more _____
strain
stresses can create _____ or _______
growth, fractures
what factors affect bone response?
mechanical properties, geometric characteristics, loading mode applied, rate of loading, frequency of loading
what is the geometric characteristics of bone?
the way the bone is shaped
what is the bone’s response to tension?
de-bonding at the cement lines and pulling out of osteons causing avulsion/tension fractures
the fracture line is often _____ to the arc of tension
perpendicular
tension fractures usually occur in bones with a large portion of ______ bone
cancellous
what is Wolff’s Law?
changes in bone shape to match function
application of forces, changes the structure
application of new forces causes _____ activity to _____ bone mass
osteoblast, increase
a decrease in usual forces causes _____ activity to _______bone mass
osteoclast, decrease
bone remodeling is influenced by….
internal forces, nutrition, aging, metabolic and disease processes
long bone is the thickest at the _____ where the bending stress is the greatest
mid-shaft
bone has a higher ____ and lower ____ on the stress strain curve
stress, strain
tendon has a higher _____ and lower _____ on the stress strain curve
stress, strain
cartilage, skin and aorta have a higher ______ and lower ______ on the stress strain curve
strain, stress
a calcaneal spur can occur as a result of the pull of what 2 structures?
plantar fascia, Achilles tendon
a teardrop fracture can occur on the anterior vertebrae as a result of the pull of what?
anterior longitudinal ligament on the anterior spine
a dislocation of the patella can occur when what tendon pulls off tibial tuberosity with it?
patellar tendon
what is the bone’s response to compression?
structure shortens and widens
failure in response to oblique cracking of osteons
can bone withstand greater compressive or tension forces?
compressive
where is a common place for compression fractures to occur?
in the spine
what is the bone’s response to shear forces?
internal deformation in an angular manner
fractures due to shear are most often seen in _____ bone
cancellous (spongy)
cortical bone is stronger in ______>_______>______
compression, tension, shear
what is a common example of shear forces pathology on bone?
slipped capital femoral epiphysis (slip of the femoral head often seen in preadolescence)
______ bone is stiffer than _____ bone
cortical, cancellous
cancellous bone can withstand strains up to _____% prior to failure
75%
cortical bone fails if strain exceeds ___%
2%
bending of bone is a combo of what 2 forces?
tension and compression
the further the bending from the _____ axis, the ______ the magnitude of stress
neutral, greater
failure of bone as a result of bending occurs on what side?
the side subjected to tension
what is a greenstick fracture?
partial fracture of a bone like trying to break a stick the isn’t quite dead yet
what is torsion force?
twist about an axis that produces torque within bone
what is the bone’s response to torsion force?
shear forces over the entire structure with tensile and compressive forces
in a torsion fracture, where does the failure initially occur? what region does failure occur in next?
it begins in the region of shear, then to the region of tension
what is repetitive loading?
forces produced by a few reps of high load or many reps of a normal load
bone fatigues rapidly when approaching the _____ ______ on the stress strain curve
yield point
why does a fatigued muscle cause bone injury?
bc a fatigued muscle doesn’t have the same ability to store energy and neutralize stress forces so it can’t offload stress as well and the bone has to take on that stress which may cause failure of the bone
t/f: good cyclical stress is good for bone and creation of osteoblasts
true, as long as it’s not overdone
what is the bone’s response to repetitive loading?
fatigue fractures
what is the most commonly encountered fracture by PTs?
fatigue fractures
fatigue fractures are about ___% of all athletic injuries
10%
____% of fatigue fractures occur in the LE
80-90%
what is the most common bone affected by fatigue fractures?
the tibia
what are 2 ways to diagnose a stress fracture easily?
MRI or bone scan
what are stress fractures often thought to be in differential diagnoses?
soft tissue injuries, compartment syndrome, infection, or other overuse conditions
fractures occur when….
bone is taken to its failure point
load exceeds linear region of the stress-strain curve
there is microarchitectural damage
what is the effect of muscles on loading of bone?
muscles contractions alter stress distribution of bone and eliminates tensile stress on bone by producing compressive stress that serves to neutralize tension
bone balance requires…
- balance b/w resorption and building must be maintained
- activities may fluctuate depending on several factors
- hormones serve tor regulate this process (parathyroid hormone, vitamin D, and estrogen)
repair by original tissue is more _____ rather than ______
regeneration, repair
what are the 2 broad phases of bone healing?
- primary osteonal (cortical) healing
- secondary callus healing
what is the primary osteonal (cortical) healing phase of bone healing?
phase in which the cortex of one side of the fracture must unit with the cortex of the other side
re-establishes continuity
what is the secondary callus healing phase of bone healing?
the phase in which there are responses in the periosteum and surrounding soft tissues
majority of the fracture repairs
what are the 4 phases of bone healing?
- hematoma
- fibrocartilagenous callus
- bony callus
- bone remodeling
what is the hematoma phase of bone healing?
blood vessels at the fx site are disrupted and leaks into the site 6-8 hours post-injury
blood flow here stops causing the adjacent bone cells to die
swelling and inflammation
phagocytes remove debris (could be several weeks)
what is the fibrocartilagenous callus stage of bone healing?
fibroblasts from the periosteum invade the fx site and produce collagen and fibrocartilage that makes the fibrocartilagenous callus
3 weeks post-injury
what is the bony callus phase of bone healing?
osteogenic cells develop into osteoblasts and begin to produce spongy bone trabeculae that joins healthy and dead portions of the og bone fragments
fibrocartilage is converted to spongy bone to form the bony callus
what is the bone remodeling phase of bone healing?
the dead portions of the og fx are reabsorbed by osteoclasts
compact bone replaces spongy bone
thickened area on the bone surface often remains
what are some common non-operative treatment options for bone fractures?
casting, splinting, braces, skeletal traction to stimulate bone growth
what is the primary approach to treating a fracture?
immobilization
what are some common operative treatment options for bone fractures?
percutaneous pinning
external fixation
open reduction and internal fixation
locking plates
intermedullary nailing
what are possible post surgical complications?
infection, venous thromboembolism (DVT or PE), poor wound healing, scars, and adhesions
what are the implications for rehab in fractures?
consider the stress-strain curve
appreciate bone healing and the importance of early mobilizations
consider adjacent soft tissues
consider the importance of muscles in shock absorption
address secondary impairments
DO NO HARM
start with isometrics with casting and ORIF if deemed safe by the physician
ROM is usually allows once the fx union has been determined
LE progressive weight bearing as allowed by the physician
what percentage of sport injuries are tendon injuries?
30-50%
what percentage of the GP consultations for MSK injuries are tendon injuries?
30%
when are tendons more subjected to injury?
high loads in eccentric and elastic conditions
what are common LE tendons that get injured?
Achilles and patellar tendons
what are common UE tendons that get injured?
supraspinatus, extensor carpi radialis brevis (tennis elbow/lateral elbow pain)
what is the composition of tendons and ligaments?
78% H2O
20% collagen
2% GAGs
tendons are good for sustaining _____, ______ tensile loads
high, unidirectional
what is the collagen arrangement of tendons?
parallel along the lines of stress
what are positional tendons?
tendons that allow precise movement
what are some examples of positional tendons?
digital flexors
what are energy-storing tendons?
typically involved in locomotion and ballistic actions
more elastic (store energy better)
what is an example of an energy-storing tendon?
the Achilles tendon that stretches during the late stance phase of gait
what percentage of strain causes uncrimping of tendons?
1-2%
what percentage of strain causes incomplete tendon tearing?
> 6%
what percentage of strain causes complete tendon tearing?
> 8-10%
in what percentage range do tendons function in?
2-6%
position tendons tend to operate in the ____ region with _____ load during use
linear, lower
energy storing tendons tend to be loaded to values close to ______ _______
absolute failure
tendons respond well to what kind of loading?
cyclical
why do tendons respond well to cyclical loading?
bc it builds more collagen and tenocytes, making them stronger
what are the effects of no cyclical loading of tendons?
reduced collagen fibers and weakened tendons
what area is the weakest point in tendons where strain injuries are common?
the MT junction area
t/f: the pathophysiology of tendons is fully understood
false!
what are some common features of tendon injuries?
pain during loading, diffuse/localized swelling, and limitations in activity and performance
what is a tendinopathy?
a painful disorder involving a tendon w/o implying the type of underlying pathology
what is the best clinical term for a tendon injury?
tendinopathy
what is tendinitis?
evidence of active intrasubstance inflammation
what is tendinosis?
no intrasubstance evidence of inflammation
which tendinopathy histology shows more degenerated/disorganized changes in collagen tissue causing pain?
tendinosis
what is the common etiology of tendinosis?
overuse and chronic overload with repetitive trauma
t/f: neovascularization is not normal in a tendon
true! it is usually the cause or result of chronic tendon irritation
tendinopathy is the absence of ____ _____ _____
prostaglandin mediated inflammation
what is likely the cause of inflammation in tendon injury?
PNS or CNS changes
t/f: inflammation in tendons is the same as everywhere else in the body?
false!
what are some structural changes in tendinopathy?
thickening
hypoechogenicity (US)
hypervascularity (Doppler US)
high signal intensity (MRI)
fiber thinning
myxoid degeneration
chondroid metaplasia
calcification
vascular infiltrates
what is myxoid degeneration?
degenerative process where CT is replaced by gelatinous material
what is chondroid metaplasia?
more chondrocytes in the tendon than there should be
what is calcification of tendons?
calcium deposits in tendons
what is vascular infiltrates in tendons?
vascularity infused into the area
t/f: the sources of pain in tendons is not easily defined?
true
what are 3 possible sources of tendon pain?
- sprouting of substance P positive nerve fibers in tendinous lesions (neurogenic/pathic cause)
- CNS output may/may not be related to physiological nociception
- changes to brain and SC excitability and cortical reorganization
what tendinopathy is a tendon rupture?
tendinitis
a tendon is most vulnerable to injury when it is ____ and attached muscle is maximally _____ or stressed
tense, contracted
tendons are most vulnerable to injury when tension is applied ____ or _____
quickly, obliquely
what are contributing factors to tendon injuries?
sports activities (most common)
work-related
drug-related
metabolic
what are the drug-related factors that contribute to tendon injuries?
corticosteroids
cyclosporine
statin
fluoroquinolone antibiotics
what are the metabolic factors that contribute to tendon injuries?
disturbed glucose metabolism
atherosclerosis
____, _____or ____ loading can cause tendon injuries
sudden, repeated, rapid
what is the primary force related to tendon injuries?
tension forces
what are internal forces in tendon injury?
one fascicle/bundle against another
what are external forces in tendon injury?
paratenon, retinaculum, bone
tendon compression results in….
shearing and friction
mechanical loading of tendons is a ____ process
anabolic
what does mechanical loading cause?
increases synthesis of collagen proteins over 24 hrs post-exercise and can stay elevated for 70-80 hrs
what is an anabolic process?
building up tissue
what is a catabolic process?
degeneration of tissues
why is there a net loss of collagen around the 1st 24-36 hrs post-training?
bc the catabolic peak is earlier than the anabolic peak so at first there is more tissue degeneration than is being built
net ____ in collagen is followed by net ____ in collagen
loss, gain
what are intrinsic factors that contribute to tendon injury?
biomechanics (malalignment, muscles weakness/imbalance, decreased flexibility, poor form)
age
adiposity (fat tissue in the body)
what are extrinsic factors that contribute to tendon injury?
excessive volume, magnitude, or speed of loading
training errors
environmental
running surfaces
does concentric contraction produce more force slow or fast?
slow
does eccentric contraction produces more force slow or fast?
fast
as velocity increases, max force in eccentrics____
increases
as velocity increases, max force in concentrics _____
decreases
what is the continuum of degeneration?
overload–>tendinopathy–> thickened/increased stiffness–>continued overload –>degenerative tendinopathy
what is an acute tendon injury?
the time and method of injury is known
may be more reactive
what is a grade I sensitivity?
pain after activity
no interference w/performace
generalized tenderness
gone by the next exercise
what is a grade II sensitivity?
minimal pain with activity
doesn’t interfere w/intensity/distance
localized tenderness
what is a grade III sensitivity?
pain interferes w/activity
usually disappears b/w sessions
definite local ttp
what is a grade IV sensitivity?
pain doesn’t disappear b/w activities
serious interference w/intensity of training
significant local signs of pain, ttp, crepitus, and swelling
what is a grade V sensitivity?
pain interferes w/sports and ADLs
symptoms are chronic and recurrent
signs of tissue change and altered associated muscle function
what factors contribute to chronic tendon disorders?
load applied
older age
gender w/hormonal fluctuations
joint motion
tendon/muscles flexibility
fluoroquinolone use
what are the 2 acute healing processes in tendons?
proliferation of tenoblasts from the cut end of the tendon
OR
vascular in-growth w/proliferation of fibroblasts from surrounding tissue which were injured at the same time (more likely)
what are the 4 stages of healing in tendons?
- hemostasis
- inflammation
- proliferation
- maturation
what is the hemostasis phase of tendon healing?
platelets form a clot
fibrin and fibronectin form a fragile bond
what is the inflammation phase of tendon healing?
infiltration of debris removing cells (phagocytes)
chemotactic signals induce fibroblasts to start synthesizing collagen
healing tissue may be able to be subjected to low-level forces w/in days
3-5 days post
what is the proliferation phase of tendon healing?
blood vessels proliferating
fibroblasts secrete type 3 collagen
in about 2 weeks collagen fibers arranging in thick bundles, randomly aligned, no cross-links, weak
2-3 weeks post
what is the maturation phase of tendon healing?
about 3 weeks post
type 3 collagen replaced by type 1
type 1 begins alignment to tensile forces and continues throughout the phase
12-16 weeks to reach level to w/stand stresses
motion allowed once integrity is restored
normal strength at about 40-50 weeks post
after healing, the new tissue is ___ and ____ than the OG
weaker, larger
healed tendons have….
increased levels of minor collagen (III, IV, and VI)
decreased cross links
increased GAGs (more ground substance=not as strong)
what is the general consensus on treatment of tendon injuries?
appropriate, carefully-graded progression of loading a tendon
initially isometric
muscles strengthening w/heavy slow resistance w/consideration of other muscles in the chain
later increase load incrementally with slow increase in speed of load application
why has isolated eccentrics been the choice treatment since the 90s?
eccentrics produce a greater max force
tendons stretch more
greater mechanical stimulation
greater frequency oscillation in tendon force
t/f: eccentric loading leads to hypertrophy and increased tensile strength of tendons?
true
does eccentrics lead to lengthening or shortening of the muscle-tendon unit?
lengthening
eccentrics normalizes concentration of ____ and enables normalization of _____ ______
GAGs, fiber arrangement
does eccentrics lead to increased or decreased paratenon capillary blood flow?
decreased
eccentrics preserve paratenon ____ saturation
O2
what does new research say about treatment of tendons?
tendons need load to recover
the type of contraction doesn’t matter
increased loads of increased duration has a better response
tensile v. compressive loads are better
patellar and quad tendons may need to be loaded at different knee angles
tendons need proper recovery to avoid further damage
t/f: s/s should guide intervention
true
t/f: in the early stage you should avoid endurance and compressive loads and focus on eccentrics?
true!
