Equine Developmental Orthopedic Disease

Question 1

What causes contracted tendons?

Answer 1

Physis matutres too rapidly

Question 2

What causes physitis?

Answer 2

Inflammation

Question 3

What causes angular limb deformities? (basic pathophysiology)

Answer 3

Physis has abnormal mechanical pressure

Question 4

What are etiologic agents of developmental orthopedic disease? (4)

Answer 4

Genetic predisposition/rapid growth
Nutritional factors (high carbs, mineral imbalances, trace minerals)
Endocrine imbalances
Trauma

Question 5

What is the most significant skeletal disorder of growing horses?

Answer 5

Osteochondrosis dissecans (OCD)
Subchondral bone cysts/cystic lesions

Question 6

Where is OCD most commonly found?

Answer 6

Femoropatellar joint, Tarsocrural joint, fetlock

Lateral trochlear ridge of femur, tarsus

Distal intermediate ridge of tibia

Question 7

Where are subchondral bone cysts most commonly found?

Answer 7

Almost always medial femoral chondyle

Question 8

What are the clinical signs of OCD in the stifle?

Answer 8

Young, fast-growing horse
Joint effusion
Variable lameness
Often bilateral involvement
Lateral trochlear ridge, medial trochlear ridge

Question 9

What are the preventative, conservative, and surgical treatments of stifle OCD?

Answer 9

Preventative: nutritional evaluation
Conservative: rest, re-radiograph
Surgical: arthroscopy (debride, inject, pin lesion)

Question 10

Answer 10

OCD of lateral trochlear ridge of hock

Question 11

Answer 11

OCD of lateral trochlear ridge of hock

Question 12

What are the preventative, conservative, and surgical treatments of hock OCD?

Answer 12

Preventative: nutritional evaluation
Conservative: small lesions without effusion
Surgical: arthroscopy to debride lesion

Question 13

Answer 13

Subchondral bone cyst
Stifle

Question 14

What are the clinical signs of subchondral bone cysts?

Answer 14

Minimal effusion
Variable lameness
Almost always medial femoral chondyle

Question 15

Answer 15

Subchondral bone cyst in stifle

Question 16

What are the clinical signs, diagnosis, treatment of physitis?

Answer 16

Lame
Radiographs
Assess/change diet
Rest/limit exercise

Question 17

Answer 17

Physitis

Question 18

What are congenital causes of flexural limb deformities? What is the pathogenesis

Answer 18

Teratogenic agents
Intrauterine positioning
Genetic predisposition
Rapid growth = D.O.D.

Question 19

What are acquired causes of flexural limb deformities? What is the pathogenesis

Answer 19

Nutritional
Trauma
Infectious polyarthritis
Pain = altered weightbearing

Question 20

Where do acquired flexural limb deformities usually occur?

Answer 20

DIP (up to 4m) or fetlock (yearlings) joints

Question 21

Answer 21

Flexural deformity

Question 22

Answer 22

Flexural deformity

Question 23

How are flexural deformities treated?

Answer 23

Evaluate nutrition, control growth rate
Control painful stimuli
Medical tx (IV oxytetracycline, splinting)
Surgical intervention

Question 24

Where do most angular limb deformities originate?

Answer 24

Physis

Question 25

Define: Valgus

Answer 25

Lateral deviation of the limb distal to the site of the deformity

Question 26

Answer 26

Valgus

Question 27

Define: Varus

Answer 27

Medial deviation of the limb distal to the site of the deformity

Question 28

Answer 28

Varus

Question 29

Answer 29

Tarsocrural valgus

Question 30

Answer 30

Fetlock valgus

Question 31

What causes congenital angular limb deformities?

Answer 31

Incomplete ossification of the cuboidal bones or epiphyses Ligament laxity (medial, lateral collateral ligaments of joints)

Question 32

What is the treatment for congenital angular limb deformities?

Answer 32

Splints! (NOT casts)

Question 33

What causes acquired angular limb deformities?

Answer 33

Nutritional imbalance Abnormal loading of the physis Trauma

Question 34

How are angular limb deformities diagnosed?

Answer 34

Radiographs Normal = angulation > 4 degrees

Question 35

What is the treatment of acquired angular limb deformities?

Answer 35

Exercise restriction/stall rest Corrective trimming +/- shoeing Minimize abnormal biomechanical forces *Re-evaluation needed in 2-3 weeks*

Question 36

How is valgus/varus corrected with feet trimming?

Answer 36

Valgus: medial side of the foot Varus: lateral side of the foot

Question 37

How are angular limb deformities surgically treated?

Answer 37

*Must act before the physis is closed* Transphyseal screw Transphyseal bridge

Question 38

Distal radius/tibia growth plate closure

Answer 38

Best therapeutic window = within 4-6 months

Question 39

Distal metacarpus/metatarsus growth plate closure

Answer 39

Best therapeutic window = within 3-4 weeks

Question 40

Transphyseal bridge

Answer 40

Bridge the side that you want to slow down growth *Valgus = medial side growing faster = bridge the medial physis*