Exam 1 - Equine Traumatic Joint Disease

Question 1

what 2 components make up the articular cartilage?

Answer 1

extracellular matrix - water, collagens, proteoglycans, & glycoproteins

chondrocytes

Question 2

what are the components of the extracellular matrix responsible for?

Answer 2

collagen - type II, responsible for tensile strength

proteoglycans - aggrecan, hold water in the joint & compressive strength

glycoproteins - link proteins

Question 3

what are the components that regulate the extracellular matrix? why can this be bad in the case of joint disease?

Answer 3

anabolic - growth factors

catabolic - cytokines & degradation enzymes

the catabolic state can turn against itself and become even more destructive

Question 4

what are the synoviocytes responsible for in the synovial fluid?

Answer 4

phagocytosis

secretory - hyaluronon/lubricin & inflammatories mediators

Question 5

T/F: there are no basement membranes in synovium

Answer 5

true

Question 6

T/F: plasma ultra-filtrate of joints good indicator of overall joint health

Answer 6

true

Question 7

what is responsible for boundary lubrication in the synovial fluid?

Answer 7

hyaluronon/lubricin

Question 8

what is responsible for nutrients/waste removal in the synovial fluid?

Answer 8

chondrocytes

Question 9

what is OA?

Answer 9

permanent & progressive cartilage degeneration

Question 10

what may be seen on arthroscopy of a joint with OA?

Answer 10

fibrillation, wear lines, & erosions

Question 11

T/F: cartilage is rather ineffective in repairing itself

Answer 11

true

Question 12

what clinical signs are seen in a horse with OA?

Answer 12

lameness, effusion around the joint, enlargement of bony structures (body’s attempt to stabilize), decreased ROM, +/- deformity

may have asymmetrical collapse especially in the digits

Question 13

what is seen on rads that is indicative of OA?

Answer 13

decreased joint space, osteophytes, subchondral sclerosis, & periosteal new bone formation

Question 14

what therapy is typically indicated for traumatic joint disease injuries for conservative therapy?

Answer 14

RICE

rest, ice, & compression - not too much elevation

NSAIDS/cortocosteroids/PSGAGS

Question 15

why is caution needed when using NSAIDS for traumatic joint disease in horses?

Answer 15

they can disrupt the body’s natural defense mechanisms & cause injury to the stomach, kidneys, endothelium, & platelets

Question 16

what is the purpose of using hyaluranon for joint injections in horses with traumatic joint injuries?

Answer 16

provides a boundary lubricant & steric hinderance to help form a barrier & potentially help induce endogenous hyaluranon

Question 17

what is an IL1-RAP intraarticular product?

Answer 17

as useful as steroid but doesn’t have all the adverse effects

Question 18

what are some clinical diseases that can result in OA in horses?

Answer 18

synovitis/capsulitis

OCD, intra-articular fractures, & primary OA

Question 19

when do we see synovitis/capsulitis in horses?

Answer 19

as a result of a repetitive soft tissue injury affecting the synoviocytes

Question 20

what is the pathogenesis of osteochondral fragmentation in horses?

Answer 20

repetitive loading - typically on the front legs - with high impact causing chronic damage, remodeling, & acute overload

Question 21

what are some components that may predispose a horse to developing osteochondral fragmentation?

Answer 21

conformation, surface they exercise on, foot/shoes, & speed/distance

Question 22

what intra-articular fractures are commonly seen in race horses?

Answer 22

C3 slab fracture, condylar fracture, & sagittal P1 fracture

Question 23

what is the pathogenesis of intra-articular fractures in horses?

Answer 23

repetitive loading of high impact leading to chronic damage, remodeling, & acute overload of the joint

Question 24

what horses do we commonly see with primary DJD?

Answer 24

race horses & quarter horses

Question 25

what is the pathogenesis of primary DJD in horses?

Answer 25

cartilage degeneration that becomes progressive & permanent

peri-articular soft tissue injuries leading to stiffening, increased focal loading, subchondral disease, & cartilage destruction

Question 26

what clinical signs are associated with primary DJD?

Answer 26

lameness - decreased performance

heat & effusion on affected joint

Question 27

how is primary DJD diagnosed?

Answer 27

clinical signs, physical exam, lameness diagnostics, rads (very definitive)

may use u/s or ct/mri

Question 28

how is primary DJD managed conservatively?

Answer 28

treat the inflammation - can’t do much to fix the problem especially in a high motion joint, so you try to slow it down

use rest, anti-inflammatories, & hyaluranon + steroids

Question 29

how is primary DJD treated surgically?

Answer 29

fragment removal if OCD, articular reconstruction, arthrodesis

Question 30

how is OCD treated in horses?

Answer 30

arthroscopy for fragment removal

Question 31

how are intra-articular fractures treated surgically?

Answer 31

reconstruction of the articular surface & lag screw fixation arthroscopically

Question 32

how is end stage primary DJD managed?

Answer 32

medical therapy & arthrodesis for end stage joint

Question 33

what condition is being treated here?

Answer 33

intra-articular fracture fixed with lag screws

Question 34

what condition is being treated here?

Answer 34

OCD - fragment removal

Question 35

what happens when catabolism takes over in a joint space?

Answer 35

cartilage becomes degraded through matrix degradation & collagen cleavage