Term
What is the definition of lameness? |
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Definition
any alteration of the horses gait. in addition, lameness can be manifested in such ways as a change in attitude or performance |
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Term
What are some important points to consider when taking a history for a lameness exam? |
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Definition
occupation/performance level, duration, cause, change with exercise, when was the horse last shod, signs, effect of treatments, performance changes |
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Term
What are you looking for in the "exam from a distance"? |
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Definition
posture, symmetry, conformation, abnormalities |
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Term
What % of a horses BW is distributed to the hind and front end? |
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Definition
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Term
Where do 95% of forelimb lameness problems occur in the leg? |
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Definition
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Term
What are some indications of posture abnormalities? |
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Definition
pointing forelimb resting hindlimb buckling at knee or fetlock dropped shoulder looks like the horse is trying to "get away from front end" |
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Term
What things are we looking for pertaining to symmetry in a lameness exam (or when would we see asymmetry)? |
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Definition
overall symmetry muscle atrophy foot size |
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Term
what is a static vs dymanic conformation |
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Definition
static: stationary exam - look from front & side(and back) dynamic: walk/trot |
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Term
how should they feet normally land when at a trot? |
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Definition
should land ever so slightly lateral to medial and slightly heel to toe |
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Term
List some differentials for abnormal swellings of the limbs |
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Definition
bony swelling, soft tissue swelling, synovial effusion (joint, tendon sheath) |
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Term
List the components to a passive physical exam |
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Definition
*systemic palpation - heat, pain/sensitivity, swelling - digital pulses, hoof - muscle - limb (tendons, ligaments, joints, tendon sheaths, bones, effusions) - range of motion (passive flexion) - check for foot balance *palpate back (caution: hind limb may kick if in pain) |
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Term
What is a Churchill hock test? |
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Definition
abduction of the limb indicates tarsal pain |
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Term
What structures are the hoof testers used for? |
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Definition
sole, wall, bars, frog, heel, navicular bone |
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Term
Describe the Active Lameness exam and its components |
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Definition
*walk *observe from front, rear, side - symmetry of gait - stride length - foot arc - foot placement *Trot straight line (2 beat) *Observe from front, back, and side - symmetry of gait - stride length - foot arc - foot placement *Hard (heel/bone issues) and soft (tendon/ligament issues) surface * Longe/circle -lameness exacerbated (due to overloading of inside) - on hard (foot) vs soft (tendon/ ligament) ground - with affected limb on the inside or outside *inside limbs for bony changes *outside limbs- tendon/ligament - Bilateral? *Under saddle - back soreness - reluctant to turn/bend in one direction - reluctant to pick up specific lead - attitude - *lameness may show at gait transitions (esp- trot -> gallop) |
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Term
What are the clinical signs of forelimb lameness at a trot |
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Definition
head nod (down on non-lame limb)when weight bearing on sound limb
head bob (up) when loading lame limb
"down on sound"
listen to hoof landing (louder on sound leg)
watch pectoral muscles |
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Term
What are the clinical signs of hindlimb lameness at a trot |
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Definition
watch a fixed point on pelvis, tuber coxae - pelvis drops (lame side) - pelvis hikes (sound side) - greatest overall excursion (top to bottom movement)-lame side |
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Term
Describe each level of the AAEP lameness scale (0-5) |
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Definition
0: lameness not perceptible under any circumstance 1: lameness difficult to observe and is not consistently apparent regardless of curcumstance 2: lameness if difficult to observe at a walk or when trotting in a straight line, but consistently apparent under certain circumstances 3: lameness is consistently apparent at a trot under all circumstances 4: lameness is obvious at a walk 5: lameness produces minimal weight bearing in motion and/or at rest or a complete inability to move |
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Term
describe how to perform a joint flexion test |
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Definition
the veterinarian holds the horses limbs (one at a time) in a flexed position and then releases the leg. as the horse trots away, the vet watches for signs of pain, weight shifting, or irregular movement
flexing the joints in this manner may reveal problems that are not otherwise readily apparent |
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Term
Give some examples of specific flexion tests and what structures they stress |
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Definition
*fetlock/phalangeal - 30sec, front: carpus straight, back: minimal hock flexion - stress: fetlock, pastern, coffin joint, tendon sheath *carpus - 60sec, cannon parallel w/ ground - stress: carpal joint, intercarpal ligaments *hind full limb - 60-90sec, cannon parallel w/ ground - stress: tarsal joints, proximal suspensory ligament, stifle, coxofemoral joint |
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Term
What is a negative vs positive grade on a flexion test |
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Definition
negative: no change from baseline positive: - mild- few steps worse than base - moderate- increased lameness down, may go back to baseline coming back - severe- obvious, severe lameness |
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Term
What is baseline lameness? |
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Definition
primary lameness recognizable before flexion or manipulative tests trotting on a firm surface in a straight line |
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Term
what is induced lameness? |
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Definition
after flexion tests or other manipulative tests exacerbated primary lameness vs additional lameness |
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Term
what is coexistent lameness? |
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Definition
secondary/compensatory/complimentary gait dependent - trot: limbs land in diagonals *if lame RH may look lame in LF *if lame RF may look lame in LH
*many horses have more than one lame leg... is it lameness? or compensation? |
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Term
What diagnostic tests can be used to isolate the specific location and cause of lameness? |
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Definition
-diagnostic nerve or joint blocks -nuclear scanning -arthroscopy -exam of blood, synovial fluid, tissue -MRI -Ultrasound -Radiographs -Thermography |
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Term
Describe the physiology of how a joint/nerve block works (including the ions involved) |
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Definition
Peripheral nerve membrane - semipermeable - K+(intracellular) Na+(extracellular) Electrical impulse-> Na+ influx - depolarization along nerve Inhibition of Na+ influx - prevents depolarization; blocks conduction |
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Term
List 4 local anesthetics commonly used for nerve/joint blocks and their duration of actions |
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Definition
Procaine: 1-1.5 hr duration Lidocaine: 1-3 hr duration Mepivacaine: 2-3 hr duration Bupivacaine: 3-6 hr duration |
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Term
List the types of nerve/joint blocks available. |
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Definition
*Regional - Perineural - local infiltration/ring *Intrasynovial - Intraarticular (joint) - intra-bursal (bursa) - intrathecal (tendon sheath) |
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Term
when should you check block efficacy & how should you check? |
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Definition
test skin sensation about 5-10 min after the block |
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Term
which type of block (nerve or joint) requires a sterile surgical prep, sterile equipment, and a new bottle of anesthetic? |
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Definition
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Term
What are some potential side effects of joint/nerve blocks? |
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Definition
Tissue damage (rare) Soft Tissue Swelling |
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Term
What are some potential side effects of joint/nerve blocks? |
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Definition
Tissue damage (rare) Soft Tissue Swelling - Needle trauma, hematoma, cellulitis (use a bandage to help reduce) Synovitis - nonseptic "flare"; septic Toxicity - Lidocaine (max dose in 500kg horse = 300mL of 2% lidocaine) |
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Term
What to look for after a nerve/joint block |
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Definition
*improvement in lameness *switch to another limb *if no improvement - more time - keep working proximally - intrasynovial blocks - other diagnostics (ie-bone scan) |
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Term
What are some instances where we might see failure to respond to a block? |
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Definition
Chronic pain, habit, neuroanatomy (can change, esp. if previous nerve trauma), intermittent/subtle, mechanical lameness, correct limb? ->recheck, wrong drug?, missed the nerve? |
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Term
List the types of nerve blocks that are commonly used |
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Definition
Palmar/Plantar Digital Nerve Block Abaxial Sesamoid Nerve Block Low 4-point: front limb Low 6-point: hind limb |
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Term
What are the landmarks for a palmar/plantar digital nerve block? |
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Definition
axial to the collateral cartilages neurovascular bundle (VAN) As low as possible |
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Term
Which is axial vs abaxial the vein or the nerve? |
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Definition
vein is abaxial nerve is axial |
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Term
what is the most commonly used nerve block and why? |
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Definition
palmar/plantar digital nerve block
because it is most distal so we usu start with this one |
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Term
What structures are blocked by the palmar/plantar digital nerve block? |
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Definition
navicular bone, navicular bursa, DDFT, Heel, Sole and Frog, DIPJ (partially) |
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Term
What nerves are blocked with an abaxial sesamoid nerve block? |
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Definition
Palmar digital nerves and dorsal branches |
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Term
What are the landmarks for an abaxial sesamoid nerve block? |
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Definition
palmar aspect of fetlock abaxial to sesamoid bones axial to artery and vein |
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Term
What structures are blocked by an abaxial sesamoid nerve block? |
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Definition
foot pastern joint distal sesamoidean ligaments
(esentially everything below the fetlock) |
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Term
Which nerves are blocked with a low 4-point: front limb block? |
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Definition
Medial & lateral palmar nerves Medial & lateral palmar metacarpal nerves
*2cc/each spot |
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Term
What are the landmarks for a low 4-point: front limb block? |
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Definition
at distal aspect of splint (palmar metacarpal nerve)
b/w DDFT and suspensory ligament (palmar nerve)
**careful of tendon sheath/joint** |
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|
Term
Which structures are blocked by the low 4-point: frontlimb block? |
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Definition
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Term
What nerves are blocked by the low 6-point : hind limb block? |
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Definition
- medial & lateral plantar nerves - medial & lateral plantar metatarsal nerves - dorsal metatarsal nerves (add SQ dorsal ring at level of button of splint) |
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Term
What structures are blocked by the low 6-point: himd limb block? |
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Definition
foot, pastern joint, distal sesamoid ligaments, below fetlock |
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Term
List the types of joint blocks that are commonly used |
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Definition
Coffin Joint block Fetlock joint block Carpal block Tibiotarsal/Tarsocrural joint block Distal intertarsal joint block Tarsometatarsal joint block |
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Term
Where do the needle pokes go for a coffin joint block and what structures are blocked? |
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Definition
Pokes: Dorsal pouch (through CDE tendon -midline), Palmar pouch (lateral approach)
structures: DIPJ, Navicular bursa, +/- DDFT insertion, +/- hoof capsule |
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Term
Where do the needle pokes go for a fetlock joint block? |
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Definition
Palmar pouch (proximal, distal) Dorsal Collateral sesamoidean ligament |
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Term
What joints are blocked with a carpal block?
What type of approach to the joint is used? |
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Definition
Radiocarpal or antebracheocarpal
Intercarpal or middle carpal
*10cc 's total
Approach: dorsal (simpler) OR lateral (preferred; protects cartilage, dont need limb held) |
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Term
What approaches are used for a Tibiotarsal/tarsocrural (hock)joint block? |
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Definition
Dorsal approach (medial or lateral) Plantar approach (VS tarsal sheath) - easiest joint to block; but not blocked often (usu. dont have problems here) |
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Term
What approach is used for an intertarsal joint block?
Which tendon is a useful landmark? |
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Definition
Approach medially* - tarsal bones:central; 1st/2nd; 3rd Tendon landmark: Cunean tendon (right above where we block) |
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Term
What approach and landmarks are used for the tarsometatarsal joint block? |
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Definition
approach: caudolaterally landmarks: above head of lateral splint bone
*blocked often* |
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Term
What is the function of a joint? |
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Definition
energy efficient, pain free movement, transport load, support musculoskeletal system |
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Term
What are the components of a joint |
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Definition
Vascular supply, ligaments, innervation, joint capsule, synovial fluid, articular cartilage, (bone) |
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Term
What is a joint capsule? What is it composed of? |
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Definition
thick fibrous portion lined by subsynovium and synovial membrane; low cellularity
composed primarily of collagen,proteoglycan, noncollagenous proteins, water |
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Term
why does the synovium have villi?
What structure is adhered to the outer portion of the synovium? |
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Definition
- increased surface area
- joint capsule |
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Term
Describe the layers of the synovium. |
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Definition
Intima: epithelial-like layer of attached CT cells (more cellular; *1-3 layers thick)
Subintima: layer of loose irregular CT (more CT); b/w intima and joint capsule; gives pliability and elasticity |
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Term
Which layer of the synovium is in contact with synovial fluid and acts as a synovial/blood barrier? |
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Definition
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Term
What cells comprise the intimal layer? and what are their functions? |
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Definition
*Type A synoviocytes: macrophage derived; phagocytic; digst debris w/in the joint
*Type B synoviocytes: fibroblast derived; produce hyaluronan (HA) and lubricin to keep the joint lubricated |
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Term
What comprises the sub-intima? how is the sub-intima important to the joint? |
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Definition
blood vessels, fat, nerves, fibroblasts, ECM
important for joint movement |
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Term
What is the function of the synovial membrane? |
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Definition
-low friction lining for the joint during movements (well-lubricated) -formation of synovial fluid -regulation of matrix turnover in synovium and cartilage (via synovial fluid) -blood synovial barrier -negative intro-articular pressure= joint stability |
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Term
What component of a joint has NO bloodsupply? why is this a problem? |
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Definition
Cartilage**
problem for healing; but vessels cant survive the compression of the cartilage |
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Term
Where do nerve fibers of the joint terminate?
Which structure in the joint is NOT innervated? |
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Definition
Terminate in: joint capsule, ligaments and menisci
Cartilage is NOT innervated (cant feel pain if cartilage is injured so injury will continue to happen) |
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Term
How do we know joint cartilage is injured if there is no innervation? |
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Definition
damaged cartilage-> build up of synovial fluid-> distended joint capsule-> pain |
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Term
Which is more damaging to a joint: joint instability or biochemical damage? |
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Definition
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Term
How does the articular cartilage recieve nutrition if there is no blood supply? |
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Definition
Synovial fluid! - an ultrafiltrate of plasma to which HA and other factors are added locally by synoviocytes (clear and viscous, low protein, few cells) |
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Term
*What is the function of synovial fluid? |
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Definition
*nourishment of articular cartilage (and "trash can") Role in joint stability: adhesive seal Lubrication: Hyaluronate**-lubrication of synovium-on-synovium and synovium-on-cartilage Lubricin- binds cartilage at surface and decreases friction |
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Term
Articular (hyaline) cartilage is composed of what 3 substances? |
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Definition
water, chondrocytes, ECM (traps water) |
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Term
What is the function of the chondrocytes in the articular cartilage? |
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Definition
**Chondrocytes: - sparse - synthesixes and regulates composition of ECM - recieves nutrients via diffusion from synovial fluid |
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Term
What is the ECM composed of? |
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Definition
collagen* proteoglycan* glycoproteins protease inhibitors, lysozyme, fibronectin, chondronectin, mineral, lipid |
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Term
What kind of collagen makes up the articular cartilage? |
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Definition
***cartilage - type II - alpha chain polypeptides -3 alpha chains->triple helix -helices-> fibril |
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Term
What is the primaryprotein core of proteoglycans foind within the articular cartilage?
what attaches to this core? |
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Definition
Aggrecan* - one or more glycosaminoglycans is attatched to the core -chondroitin sulfate, keraten sulfate, dermatan sulfate |
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Term
What is the structure/function of proteoglycans? |
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Definition
- attach to HA backbone via link protein to form large MW complexes
- high densty negative charges from the GAGs keeps the molecules separated and traps water
- osmotic properties provide resistance to compression |
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Term
Describe the physical and mechanical properties of articular cartilage |
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Definition
-Decrease frictional forces during joint movement -Load distribution during weight bearing -loads shared by various components - *Tensile forces resisted by osmotic pressure provided by proteoglycans* - Compressive forces resisted by osmotic pressure provided by proteoglycans** - proteoglycans provide viscoelastic properties and collagen provides stiffness by counteracting the swelling pressure** |
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Term
Which is more likely assoc with a biomechanical issue vs a biochemical issue...
abnormal stresses, normal cartilage normal stresses, abnormal cartilage |
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Definition
biomech: abnormal stress, normal cart. biochem: normal stress, abnormal cart. |
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Term
List important inflammatory mediators |
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Definition
**Proteases: enzymes that break down proteins/peptides by catalyzing the hydrolysis of peptide bonds (examples: Metallo, srine, cysteine)
-cytokines, prostaglandins, O2 derived free radicals, growth factors |
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Term
**What are Matrix metalloproteinases (MMPs)? |
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Definition
- inflammatory mediators -enzymes that degrade the ECM of articular cartilage - released in latent form requiring activation -categorized according to the part of the ECM that is degraded (substrate) |
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Term
List some examples of matrix metalloproteinases and what their action is |
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Definition
**Collagenase: MMP-1,-8(sepsis),-13(key)* - cleaves collagen triple helices**
Gelatinase: degrades denatured (unwinding)type II collagen Stromelysin: degrades proteoglycans |
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Term
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Definition
tissue inhibitors of metalloproteases - TIMP 1-4 - bind one-to-one complex inhibiting MMP action |
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Term
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Definition
**cleave aggrecan
- ADAMTS - inhibited by TIMP-3 |
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Term
What do MMPs and aggrecanases (ADAMTS) have in common? |
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Definition
they are both inflammatory mediators that break down collagen |
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Term
List the two important inflammatory cytokines** |
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Definition
Interleukin-1 and Tumor Necrosis Factor |
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Term
What is TNFa responsible for? |
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Definition
-influx of leukocytes -secretion of chemokines -induction chondrocyte apoptosis -stimulates production of MMPs by chondrocytes and synoviocytes -inhibits proteoglycan synthesis -increased adhesion molecules |
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Term
List some important anti-inflammatory cytokines |
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Definition
IL-4,IL-10 :both decrease IL-1,TNF,MMPs
IL-1 receptor antagonist (IL-1a) |
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Term
What is the most commonly involved prostaglandin and what is its role? |
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Definition
*PGE2 - causes proteoglycan depletion from ECM**; enhances pain perception** - production stimulated by IL-1 |
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Term
What produces O2 derived free radicals and what is the role of free radicals? |
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Definition
produced by neutrophils and macrophages
**can occur as result of ischemia/ reperfusion injury**
Cleaves proteoglycan, collagen, and HA |
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Term
What are the consequences of imflammatory mediator actions on ECM?*** |
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Definition
-initial biochemical damage to cartilage w/out gross abnormalities - accelerated degradation of collagen and proteoglycan - inability of chondrocytes to synth. collagen & proteoglycan -Weakened cartilage less resistant to loading and sheer stress -Gross cartilage lesions develop unless inciting cause corrected and inflam process controlled -wear particles from damaged cartilage can initiate further mediator production by synovium -spontaneous repair of cartilage lesions in incomplete or not at all |
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Term
Do cytokines and degradative enzymes lead to increased catabolism or anabolism of the joint? |
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Definition
catabolism
*result= impaired joint function |
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Term
What are some Developmental joint diseases |
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Definition
-Osteochondrosis dessicans -Subchondral cystic lesions -delayed ossification |
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Term
What is osteochondrosis?** |
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Definition
failure of endochondreal ossification results in thickened cartilage (failure of cartilage to turn into bone) |
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Term
What is Osteochondrosis dissecans (OCD) |
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Definition
thickened cartilage cracks and creates a cartilage/bone flap (often a result of trauma) - trauma tore into cartilage and bone |
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Term
T/F: OC may result in OCD |
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Definition
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Term
T/F: OCD always results from OC |
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Definition
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Term
What is the signalment and clinical signs of developmental orthopedic disease? |
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Definition
Signalment: young animal Clinical signs: joint effusion, mild to moderate lameness (1-2/5) |
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Term
What are some modes of sustaining infection in joint sepsis? |
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Definition
-direct penetration of joint -extension of infection from adjacent tissues (ie. physis) -hematogenous |
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Term
What is the signalment and clinical signs assoc. w/ joint sepsis |
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Definition
signalment: any age Clinical signs: extreme pain (non-weight bearing), heat and swelling around joint and severe effusion of joint, depressed, off feed, febrile (not common in LA-> if an adult is febrile look for other causes) |
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Term
**What is the definition of osteoarthritis (OA)? |
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Definition
OA is a group of disorders characterized by a common end stage - progressive deterioration of the articular cartilage - accompanied changes in the bone and soft tissues of the joint |
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Term
List the **clinical signs associated with osteoarthritis |
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Definition
joint pain/lameness, limited range of motion, joint effusion, variable degrees of local inflammation |
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Term
Describe the pathologic signs and results of osteoarthritis.** |
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Definition
-irregularly distributed partial or full thickness cartilage loss - loss of shiny, smooth surface; grooves or wear lines -Increased subchondral bone density -Osteophyte formation -Variable synovial inflammation |
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Term
What general things do you need to consider for treatment of joint disease |
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Definition
- use of animal - age - size - disposition - economics - owner compliance |
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Term
WHat is the most important form of trx? |
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Definition
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Term
Describe why rest is an important trx in joint disease. |
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Definition
reduces acute inflammation which reduces production of cytokines and MMPs
even a few days is often helpful (sometimes need a few weeks) |
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Term
What is/are the goal(s) of surgery for the trx of joint disease |
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Definition
Remove inciting cause when possible (minimize biomechanical issue) - osteochondral fragment removal Debridement of surface defect |
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Term
What are some surgical procedures that may be preformed in joint disease trx? |
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Definition
-internal fixation and joint reconstruction -lavage and decontamination -soft tissue debulking and debridement -arthrodesis (if gross instability) |
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Term
What types of physical therapy may be used for joint disease trx? |
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Definition
- hydrotherapy - ice - swimming - acupuncture/chiropractics - "soft" laser therapy - Galvanic or faradic electrical stimulation -therapeutic ultrasound -counterirritants -radiation -extracorporeal shock wave -massage -superficial heat |
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Term
How might nutrition be used in the trx of joint disease |
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Definition
-balanced diet - supplement if necessary (be careful; not needed w/ a balanced diet) - weight control - modulation of immune response and inflammation via fatty acids |
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|
Term
What drugs may be used to trx joint disease |
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Definition
NSAIDs Corticosteroids Hyaluronan Adequan(polysulfated glycosaminoglycan) Tetracyclines IRAP(IL-1 receptor antagonist protein) Neutraceuticals |
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|
Term
What is the mechanism of NSAIDs |
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Definition
**inhibits COX to reduce prostaglandin production |
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Term
***Describe corticosteroid use to trx joint disease |
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Definition
-intra-articular most common (Methylprednisolone acetate; Triamcinalone acetonide) -Potent inhibitors of joint inflam. -Reduce GAG synthesis -May be chondroprotective - sustains chondrocyte metabolic activity and inhibits degradative enzymes -Detrimental effects largely overstated |
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Term
What is the mechanism of corticosteroids as they relate to blocking inflammation |
|
Definition
block Phosphlipase A2 conversion of phospholids to arachodonic acid |
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|
Term
What drug will inhibit MMPs |
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Definition
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|
Term
List some diseases of the distal limb |
|
Definition
-angular limb deformities* -physitis -splints -splint bone fractures |
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|
Term
List the causes of angular limb deformities |
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Definition
-asynchronus physeal growth -ligamentous laxity -tarsal/carpal cuboidal bone collapse -carpal/tarsal bone fractures |
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|
Term
How would you Dx angular limb deformities? |
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Definition
determine cause of deformity - visual assessment - palpation for laxity lameness Hx-prematurity or trauma radiography |
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|
Term
List some angular limb deformities |
|
Definition
carpus- valgas (outward angulation) fetlock- varus (inward angulation) tarsus- valgas
-any combo of the above -shound NOT be lame (if lameness is present look for other causes) |
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