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Tendons
tendon
78
Anatomy
Graduate
10/02/2013

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Term
what is the breakdown of tendon composition
Definition
20% cellular, 56% water, the rest is mostly collagen with some GAGs
Term
what type of cell makes up tendon matrix
Definition
fibroblasts
Term
what is the main component of tendon
Definition
collagen
Term
describe the architecture of collagen
Definition
hierarchical. Multiple layers of organization. Grouped kind of like muscle.
Term
what is the collagen orientation when tendon is unloaded
Definition
wavy, crimped
Term
what is the collagen orientation when tendon is loaded
Definition
straightened, aligned, parallel, only a few fibers in other directions
Term
what is the job of a tendon
Definition
deliver force from muscle to bone
Term
why do we want collagen fibers in tendon to be aligned
Definition
to deliver the tensile stress/force going through them.
Term
what are microscopic characteristics of chronic tendinosis
Definition
reduced collagen content - replaced by mucoid ground substance. Collagen fibers not in a nice alignment = weak.
Term
what is unique about a tendon's stress-strain curve
Definition
there is a small toe region where it takes up the crimp. Once the crimp is taken up, the tissue becomes stiff as stress and strain increase
Term
at what % strain does tendon fail
Definition
10.00000%
Term
what do we see on the stress strain curve of tendon prior to macrofailure
Definition
successive microfailures
Term
what are the microfailures
Definition
places where additional strain occurs without additional stress because of shearing between adjacent collagen fibers or adjacent collagen bundles
Term
what are tendon mechanisms for injury (4)
Definition
tensile stress, frictional abrasion, compression, interface injuries
Term
describe tensile stress as tendon MOI
Definition
too much magnitude, frequency, duration can damage tendon tissue
Term
describe frictional abrasion as tendon MOI
Definition
bony or retinacular pulleys: where tendons wrap around bone they will have frictional abrasion, compressive stress, and tensile stress. Example = carpal tendons
Term
where can compression be an MOI for tendon injury
Definition
bony or retinacular pulleys.
Term
where would you see a tendon interface injury
Definition
musculotendinous or bone insertion site junctures
Term
is it easier to heal muscle tendon injury or tendon bone injury
Definition
easier to heal muscle tendon injury
Term
how does tendon's metabolic issues affect healing
Definition
poor or nonexistent blood supply, poor lymph supply, no good access to reparative cells
Term
what happens to tendons with increased use
Definition
increase in size and number of collagen fibers = hypertrophy
Term
what happens to tendons with decreased use
Definition
decrease in size and number of collagen fibers = atrophy
Term
how does temperature affect tendon mechanics
Definition
increased temperature increases ultimate strength and strain at failure
Term
how does age affect tendons
Definition
no great change in ultimate strength until 7th or 8th decades
Term
what is indocin
Definition
medication shown to increase total collagen content and ultimate strength
Term
when might indocin application be helpful
Definition
supraspinatus tendon: right where it wraps around the humeral head in the subacromial space in an avascular region it can have frictional abrasion, compression, impingement. If you have tendonitis there, indocin could be helpful.
Term
how do steroid injections affect tendons
Definition
steroids weakens collagen structure, doesn't do a single thing to address what is causing the problem, masks the pain so that the person starts doing things they shouldn't be doing that can increase injury, when the pain returns the patient thinks he needs another shot, wastes time and money
Term
are there potential adverse effects of prolonged oral prednisone for RA or other systemic inflammatory conditions on tendons?
Definition
yes
Term
what are guidelines for steroid injections
Definition
inject around and not into tendon, decrease activity for several weeks after injection, never repeat again
Term
what are side effects of steroid injection
Definition
skin atrophy, fat pad atrophy, tendon rupture
Term
what is the effect of fluoroquinolones on tendon
Definition
causes disruption of collagen structure, leads to tendon rupture. Especially bad in older adults, women, people taking prednisone, people with renal disease
Term
what are tendon pulley injuries
Definition
injuries of tendons at bony or retinacular pulley mechanisms where tendons wrap around.
Term
what 3 forces cause tendon pulley injuries
Definition
frictional abrasion, compressive stress, tensile stress
Term
what to do if you think tensile stress is causing tendon pulley injuries
Definition
1. keep the muscle quiet. Keep it from tugging with too much magnitude, frequency, duration; 2. heat the muscle and stretch it; 3. check the other side of the joint to see if the involved muscle unit is compensating for something
Term
how is there compressive stress in the tendon pulley?
Definition
the tendon is attached at one end to the bone. It wraps around another bone and is pulled in another direction by a muscle. It forms an angle and is pulled in different directions, causing compressive stress at the pulley. This stress is the resultant of the two different pulling forces
Term
what are 3 ways that the compressive stress at the pulley could be increased?
Definition
the more you contract, the greater the 2 pulling forces, and the greater the resultant force that goes between the 2 pulling forces and pulls the tendon into the pulley. The more acute the angle, the greater the resultant force. The more the tendon wraps around/touches the pulley, the more compressive stress there is.
Term
describe what happens to tendons in the carpal tunnel when you extend your wrist
Definition
you increase tendon force by activating the muscle, and you also make the angle more acute by extending your wrist. Double whammy for increased compressive forces.
Term
what position should a wrist be kept in if it has carpal tunnel syndrome
Definition
neutral
Term
do you want a lot of radial or ulnar deviation if the person has carpal tunnel syndrome
Definition
no.
Term
at what position is the size of the tunnel at its largest
Definition
neutral
Term
is vibration good or bad for carpal tunnel
Definition
bad. Wear heavily padded gloves
Term
how to treat someone with supraspinatus tendinitis
Definition
rest in abduction and flexion using armrest or pillow. Don't sleep on the ipsilateral side (adduction increases acuity of the angle)
Term
what is another problem of pulleys?
Definition
wringing out blood supply
Term
what position reduces blood supply to supraspinatus tendon
Definition
extension and adduction reduces blood supply in supraspinatus tendon because it stretches the tendon across the humeral head AND because it decreases the angle.
Term
what location of the long head of the biceps is its worst blood supply
Definition
where it wraps around the humeral head
Term
how does concentric muscle action affect a pulley?
Definition
the muscle is shortened, so the direction of movement goes toward the muscle. Friction is in the opposite direction. Increases force and friction between pulley and tendon
Term
with concentric contraction, which side of the tendon is Tmax
Definition
the side next to the muscle. This is where the force is pulling from.
Term
what is the formula for frictional abrasion
Definition
Log10Tmax - Log10 Tmin = 0.4343μα
Term
what does the formula for frictional abrasion mean
Definition
the larger the muscle tendon forces,t he greater the friction
Term
what is alpha in the frictional abrasion equation?
Definition
arc in contact: how much the tendon wraps around
Term
how does the arc in contact affect frictional abrasion
Definition
the greater the arc in contact, the greater the frictional abrasion AND compressive stress AND tensile stress
Term
what is the affect of a tight tissue opposite the concentric muscle contraction
Definition
Tmax has to be even greater, which will increase frictional abrasion
Term
when a muscle is eccentrically contracting, which side of the tendon is Tmax
Definition
the side connected to the bone.
Term
why do you not want the tibialis posterior to wrap around the medial malleolus too much?
Definition
when you go into pronation, you'll passively stress the muscle tendon unit so that the tensile stress will increase, the angle between the two tendon forces will be more acute, and the combination of things will result in a lot of compressive stress.
Term
what to do for someone who pronates a lot
Definition
heel lift, medial wedge
Term
what benefits do you see by controlling pronation
Definition
decreases resultant tendon force, decreases compression, decreases frictional abrasion
Term
what interventions to do for tendon problems/
Definition
address tendon pulley issues, identify other MOI such as intensity, frequency, duration and remove patient from MOI. Try other equipment
Term
when is acute tendinitis
Definition
within the first week, when there's still inflammation there
Term
what to do to treat acute tendinitis
Definition
rest, NSAIDs, ice, gradual return to activity after solving MOI problem, heel lift or modification
Term
define tendinopathy
Definition
pathologic condition within tendon tissue
Term
define tendinitis
Definition
acute inflammatory process within tendon. Most people we see do not have tendinitis.
Term
Define tendinosis.
Definition
tendinopathy lasting longer than one week. Chronic degeneration of tendon tissue with reduced collagen fiber content and increased volume of mucoid ground substance, disrupted collagen orientation, absence of inflammatory cells.
Term
will anti-inflammatory drugs help someone with tendinosis
Definition
probably not. In fact, it will mask the pain and real pathology
Term
what is chronic tendinosis
Definition
chronic tendon trouble
Term
how to examine a patient with chronic tendinosis
Definition
1. see where they are TTP: start with area outside the discomfort, mark the discomfort area with a pen and measure its size.
Term
how to treat someone with chronic tendinosis
Definition
1. heat up the tissue to make it stronger and more extensible. 2. apply vigorous transverse friction massage to release adhesions. 3. brief bout of heavy controlled loading for muscle tendon juncture or midsubstance tendinosis. 4. stretch. 5. ice if needed. 6. rest. 7. return to activity if minimally TTP
Term
is this aggressive approach good for bone insertion tendinopathy?
Definition
no
Term
describe the brief bouts of heavy loading for midsubstance and muscle-tendon juncture tendinosis
Definition
3 sets of 12-15 reps to fatigue muscle
Term
how to treat tendon-bone insertion tendinosis
Definition
rest, NSAIDs, very cautious return to loading
Term
is it better to do eccentric or concentric loading of tendon with tendinopathy
Definition
unclear. BUT before you send the patient out into the real world, you need to advance them to being able to do eccentric loading: hypertrophy the muscle tendon and bone insertion site to prepare them for the unpredictable
Term
when lifting an object at the wrist by extending against gravity, is there more tensile stress in the common extensor tendon in concentric lifting or eccentric lowering and why?
Definition
more tensile stress in concentric lifting because the angle is getting smaller and the moment in the muscle group has to be greater than the resisting weight force. There is more force transmitted through the tendon during concentric phase
Term
why might eccentric lowering still be harder?
Definition
we have more problems controlling eccentric movement than concentric movement
Term
what is the evidence on iontophoresis with dexamethazone
Definition
short term (1 month)benefits for lateral epicondylitis and plantar fasciitis. 12 month benefits for Achilles tendinosis
Term
what is the evidence on iontophoresis with acetic acid
Definition
no good
Term
what must you remember about modalities
Definition
you still have to address the MOI
Term
what are some additional treatments for calcific tendinitis
Definition
disodium EDTA = chelator that pulls calcium out of calcium deposit; acetic acid dissolves calcium deposit; extracorporeal shock wave
Term
how do protein growth factors promote tendon healing
Definition
insulin growth factor stimulates tenocytes to produce more collagen and produce stronger healing tendon.Similar results for other proteins
Term
is surgical or non-surgical treatment better for Achilles tendon ruptures and why
Definition
surgical might be better: fewer re-ruptures, earlier returns to activity, more return to full activity, usual surgical risks
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