OCD Flashcards by Sydni A

T/F: OCD is a common cause of lameness in older horses

False
younger horses

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what is the pathophysiology of OCD development

focal failure of endochondral ossification

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what does growth cartilage fail to undergo, causing OCD

calcification and vascular invasion

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what does endochondral ossification provide

limb length and joint shape

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what is the limiting factor to development of OC

restricted to time of active endochondral ossification

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growth cartilage starts off ____ and then ____ as the horse matures

thick, thin

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what are the two outcomes of a defect in ossification

OCD lesion, or subchondral cyst

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what are the factors that aid in OCD develpment

genetics, rapid growth, large size, biomechanical forces, nutrition, hormonal

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what type of genetics is OCD

polygenic

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T/F: each joint has a different level of heritability

true

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T/F: OC phenotype has only genetic components, not environmental

false - has both

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what joint has the highest heritability for OCD

tibiotarsal

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regarding forces causing OCD: excess force on ____ tissue

normal

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regarding forces causing OCD, normal force on ____ tissue

abnormal

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what is the best exercise regime to decrease development of OCD

exclusively on pasture until 1 year old

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what are the other exercise regimes that are risk factors to OC development

irregular access to pasture, and mixed housing

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what type of terrain predisposes to OCD

rough or slippery

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T/F: conformation is a predisposition for OCD

true

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window of vulnerability for nutrition impact of OCD development is dependent on what

age and joint

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what are mares fed during pregnancy that make them less likely to produce foals with OC

not fed concentrates

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what are foals fed that cause a higher degree of OC

concentrates

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foals not fed concentrate have what relationship to OCD development

higher probability of healing OCD lesions

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what type of effect does insulin have on enchochondral ossification

direct

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insulin stimulates the removal of what

T3 and T4

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what effects does T3 and T4 have

required for normal chondrocyte differentiation and vascularization of growth cartilage

relationship of high energy feeds and insulin

higher post prandial glucose and insulin responses to a high grain ratio in horses with OC

what nutritional and exercise combination has the highest incidence of OC

fed excessively with a low activity level

what nutritional ratio is important

calcium/phosphorus ratio

what does high phosphorus trigger (>4x recommendation)

secondary hyperparathyroidism

T/F: clinical presentation of OC can be normal

true

what are both clinical and radiographic signs of OC

effusion, lameness (+/-)

what are only radiographic signs of OC

subchondral lucency, fragment/flaps

what is the gold standard for diagnosing OC

radiographs

what are only clinical signs seen with OC

effusion and lamenessh

what are the limitations to radiographs for OC lesions

cartilaginous lesions only will not show up, small lesions hard to see, superimposition of structures, and lack of mineralization in young

what is the advantage of US over radiographs for OC lesions

can image joint surface

what is the number one joint to develop OC

tibiotarsal joint

where on the tibia is the #1 area for OC development

DIRT --> distal intermediate ridge of tibia

what other structures of tibiotarsal joint can get OC

distal lateral trochlear ridge, medial malleolus

what structure of femoropatellar joint develops OC

trochlear ridges (Lateral >> medial), trochlear groove, articular surface of patella

what structure of MCP/MTP joint develops OC

dorsal mid sagittal ridge, MC/MT III condyles

what are other joints that can develop OC lesions

pastern, shoulder, cervical vertebrae

T/F: OC is a bilateral/quadrilateral disease that presents bilaterally

false -- presents unilateral

what should you do if you have OC in one fetlock joint

investigate all others --> usually quadrilateral

grade I OC in femoropatellar joint

<2 cm in length

grade 2 OC in femoropatellar joint

2-4 cm in length

grade 3 in femoropatellar joint

>4 cm in length

what radiographic view of the stifle is best for OC detection

oblique

T/F: palmar/plantar OC fragments in the MCP/MTP joints are not part of OC process

true

type 1 of fetlock joint

flattening only

type 2 of fetlock joint

flattening, fragmentation

type 3 fetlock joint

flattening w/or w/o fragmentation at lesion site and a loose body

what radiographic view is the best view for fetlock OC detection

lateral flexed

age range of radiographic changes in tibiotarsal joint

<1 month, up to 5 months old

age range of radiographic changes in stifle joint (lateral trochlear ridge)

3 months old, with peak at 6 months

age range of radiographic changes in femur (lateral ridge femoral trochlea)

born normal, peak at 6 months, healed by 8 months

T/F: OC lesions can spontaneously regress in young foals

true

what is the age of no return

12 months overall

age of no return for tibiotarsal joint

5 months

age of no return for femoropatellar joint

8 months

what structure has better healing potential

talus > tibia

what are the parameters for conservative management

very young lesions <2 cm long, <5cm deep no fragmentation MCT/MTP type I lesions

what is the conservative treatment plan

rest, controlled exercise, IA medications

are intraarticular medication recommended?

not of great value, can be harmful

what is the treatment of choice for OC lesions

surgical management

list the surgical management techniques for OC

arthroscopy, reparative techniques, and regenerative medicine techniques

pros of arthroscopy to tx OC

inspect and palpate cartilage, remove loose cartilage flaps, debride tissues

what is the reparative techniques

PDS pins (like the suture) research setting

what is the purpose of regenerative medicine techniques

PRP, BMP2, MSC, gelatin impregnated spongoe brings in mediators for healing

once the damaged cartilage is removed and bone is exposed, what will cover the bone

fibrocartilage

prognosis of OC

fair to good

what does prognosis depend on

severity of lesion

what is the definition of favorable outcome

established with the owner, the goal and client expectation

what joint has a 64% success rate

femoropatellar joint with lateral trochlear ridge

what joint has 73-83% success rate

tibiotarsal joint

what joint has a 90% success rate

fetlock - depends on location and severity

causes of subchondral cystic lesions

OC, trauma, septic arthritis

trauma to what causes SCL

articular cartilage or subchondral bone

most common lesion location for SCL

medial femoral condyle

what other areas can develop SCL

phalanges

breed predisposition for SCL

TB > QH

what radiographic view is best for SCL

caudal-cranial view

what clinical signs will you see if SCL is associated with an OC lesion

mild-severe lameness seen at initiation of training

why will you see pain associated with a SCL

due to development of synovitis, increased intraosseous pressure, and increased intra-cystic pressure

what modalities can be used to diagnose SCL

radiography, CT, and US

best radiographic view of distal limb for SCL

dorsopalmar/plantar

why would you do a CT for SCL

if small lesions, to know exact location, if fissure lines present, and to see if any articular communications

conservative tx of SCL

rest and NSAIDS biphosphonates IA or intralesional corticosteroid/HA

MOA of biphosphonates

inhibit osteoclastic activity - unknown if actually helpful

1st approach to conservative tx of SCL

IA or intralesional corticosteroid or HA injection - immediate improvement, but recurrence of signs

if lameness is present along with an SCL, what is the treatment of choice

surgical intervention

steps of surgical intervention for SCL

1. intralesional injection of TA 2. surgical debridement 3. transcortical screw insertion

methods of surgical debridement for SCL

arthroscopic, transcortical approach

purpose of transcortical screw for SCL

promotes bone formation and stabilizes fissure lines; can drill out cyst through side uni-cortical position screw

what is prognosis of SCL dependent on

age, breed, location, size, DJD, and tx choice

who has a decreased prognosis with SCL

older with OA bilateral lesions upright conformation

what is the predictor of success for SCL

cartilage involvement >depth of lesion

OCD Flashcards

(97 cards)