LA MS 7: LA OCD

Question 1

OCD PP

Answer 1

Failure of endochondral ossification

Question 2

Vascular Failure

Answer 2

Cartilage gets traumatized while soft so doesn’t turn into bone
Loss of vasculature before have opportunity to turn it into bone

Question 3

Implicated etiologies for vascular failure

Answer 3

Genetics
Growth rate - linked
Nutrition: low copper, excess zinc or energy
Gender: questionable
Exercise: excess likely involved - more important in propagation than development
All linked together –> genetically predisposed to grow lrg and fast, fed more, large foals have increased trauma to growth cartilage

Question 4

Exercise and OCD

Answer 4

OCD fragment there - during exercise can wobble –> see CS

Doesn’t mean that exercise caused the OCD!!!

• -didn’t form because started training too young
• -Training led to OCD fragment becoming wobbly and dislodging

Question 5

CS

Answer 5

Articularepiphseal growth cartilage
Physis
Remodeling, closure of growth plate

Question 6

Physeal OC

Answer 6

“Physitis, epiphysitis” - growing pains
Most commonly dx’d in distal radius during growth spurt of lrg, fast-growing foals
Uncertain link to OC

Question 7

Physeal OC CS

Answer 7

Variable Lameness 
Enlarged physes, tender to palp 
Look sore 
Nobly knees 
Holding the leg up

Question 8

Physeal OC Dx

Answer 8

Rads - wide, irregular physes, metaphyseal flaring

Question 9

Physeal OC Tx

Answer 9

NSAIDS, rest - avoid running
None
Self-limiting dz
Good prognosis

Question 10

Articularepiphseal Complex OC - CS

Answer 10

Synovitis 
--+/- Lameness 
--eventually lead to O 
Lameness
--increased after work/flexion 
Synovitis +/- Lameness typically dramatic w/ free fragments - not necessarily related to prognosis

Question 11

Synovitis

Answer 11

Tibiotarsal jt effusion “bog spavin”

FP jt effusion “gonitis”

Question 12

Most Freq OC Lesions - femoropatellar

Answer 12

Lateral trochlear ridge

Patella

Question 13

Most freq OC locations - hock

Answer 13

Distal intermediate ridge of the tibia
Lat and med trochlear ridges of talus
Medial malleolus

Question 14

Most freq OCD locations - shoulder

Answer 14

NIGHTMARE
Humerus
Glenoid
Mostly go undx’d until too late because not on people’s lists and shoulder RADS difficult to obtain
–prog terrible if have issues on both sides of the jt

Question 15

Most freq OC locations - MC/MTphalangeal

Answer 15

Sagittal ridge

Condyles of MCIII and MTIII

Question 16

Other OCD Locations

Answer 16

Cervical vertebrate - Wobbler’s (OCD in neck facets of C2, C3, and C4)

Question 17

Tx OC Lesions

Answer 17

Single or multiple fragments

Standard of care: take out fragment, debride bed so that don’t get recurrent jt filling, and fill with graft or MSCs

Question 18

Lesions that are prob not OC

Answer 18

Medial femoral condyle cysts

Axial palmar/plantar prox phalanx fragments aka PP1

Question 19

Medial Femoral Condyle Subchondral Bone Cysts

Answer 19

Horses 1-8yrs (DT trauma in younger horses)

QH predisposed - conformational predisposition

Question 20

Medial Femoral Condyle Subchondral Bone Cysts CS

Answer 20

Effusion
Variable severe lameness - can come and go because has a ball valve. When ball valve closes, synovitis resolves
–pain DT synovitis
Can be pos to flexion tests

Question 21

PP1 Fragments

Answer 21

Occur at insertion of short distal sesamoidean ligament on P1
–avulsion fracture
–no histologic evidence of retained cartilage
Occurs with greatest freq in STB
Clean articular break (vs OCDs which have a crumbly, brown sugar retention of cartilage)

Question 22

Tx PP1 Fragments

Answer 22

Fix
Remove
Leave alone
Arthroscopy - frag removal and lesion debridement

Question 23

PP1 Prognosis

Answer 23

Age of horse
Age of lesions
Extent of lesion
Pretense of OA on RADS or intraop

Question 24

OCD In cattle

Answer 24

Surgical tx necessary for long term success

Clinicially manifests in 1 jt
Stifle > tarsi > carpi > shoulder > digit
Majority have concurrent OA at time of dx