Exam 2: Osteochondritis Dissecans (OCD)

Question 1

__________ factors that stress the weakened osteochondral junction

play an important role in the clinical manifestation of osteochondrosis

and may ultimately determine whether healing or osteochondritis dissecans flap formation ensues.

Answer 1

Biomechanical

Question 2

At what age is OCD seen in horses?

Answer 2

TWO age ranges:

Birth to 5 months

and

> 1 year old

Question 3

Which 2 NSAIDS are used as anti-inflammatories

in the treatment of OCD in the equine?

Answer 3

Flunixin and Phenylbutazone

Question 4

In regards to osteochondrosis,

exercised foals tended to have lesions involving the ________________

Answer 4

lateral trochlear ridge of the femur.

Question 5

Small-chain collagen type in mammalian articular cartilage

May have a cell-signaling function

Answer 5

Type 6 collagen

Question 6

What are the two pathophysiological causes of OCD?

Answer 6

Failure of blood vessels to penetrate calcified cartilage

Epiphyseal necrosis

Question 7

_______ supplementation of mares during pregnancy may help decrease the prevalence of osteochondrosis

Answer 7

Copper

Question 8

Aberrant local signaling to the ____________

in the deep layer of the articular epiphyseal-cartilage complex

is believed to underlie the development of osteochondrosis

Answer 8

chondrocytes

Question 9

Which location is more likely to be affected by OCD

in the fetlock of the equine:

Sagittal ridge of MC3

Palmar/Plantar eminence of P1

P1 or MC3 Cysts

Answer 9

Sagittal ridge of MC3

Question 10

Greater weight gains during the ___ and ____ months of life

appear to have the most influence on the development of osteochondrosis.

Answer 10

3rd and 5th months

Question 11

What location is most commonly affected by OCD

in the Tibiotarsal (Tarsocrural) Joint (AKA HOCK)?

Answer 11

Distal intermediate ridge of the tibia

Question 12

Major collagen type in hyaline cartilage

Answer 12

Type 2 collagen

Question 13

During bone formation,

_____________ form calcified columns in the hypertrophic zone

Answer 13

Chondrocytes

Question 14

What is the half-life of technetium-99 and how is it excreted?

Answer 14

12 hours, excreted via urine

Question 15

Which location is more likely to be affected by OCD

in the stifle of the equine:

Lateral trochlear ridge

Medial trochlear ridge

Answer 15

Lateral trochlear ridge (#1 location in stifle)

Question 16

What nutritional factors are involved in the epipathogenesis of osteochondrosis in horses?

Answer 16

LOW calcium, copper, selenium

HIGH phosphorus, zinc, molybdenum

Vitamin A,D deficiency

High protein diet

High caloric intake

Question 17

For an arthroscopic procedure,

after the arthroscope is introduced, the egress cannula

is used with this technique to help facilitate direction

of the procedure

Answer 17

Triangulation technique

Question 18

_______ is the only tissue in the body that can heal without scar formation

Answer 18

Bone

Question 19

T/F: Degenerative osteoarthritis is a heritable trait

Answer 19

TRUE

Question 20

Which location is more likely to be affected by OCD

in the hock of the equine:

Lateral trochlear ridge

Medial trochlear ridge

Answer 20

LATERAL trochlear ridge

(DIRT is still #1 though)

Question 21

The process of abnormal bone and cartilage formation is known as

Answer 21

osteochondrosis

Question 22

What 3 factors stimulate terminal differentiation of Chondrocytes?

Answer 22

Indian hedgehog

• Bone morphogenetic protein 6
• Bone morphogenetic protein 2

Question 23

Compared with other affected foals,

foals confined in stalls tended to have more severe lesions,

and the _________ were more often affected.

Answer 23

femoral condyles

Question 24

Which location is more likely to be affected by OCD

in the hock of the equine:

Lateral malleolus

Medial malleolus

Answer 24

Medial malleolus

(DIRT is still #1 though)

Question 25

What location is most commonly affected by OCD in the FETLOCK?

Answer 25

Sagittal ridge of MC3

Question 26

Where in the stifle is this located and what is the arrow pointing to?

Answer 26

Medial Femoral Condyle, Cyst

Question 27

What is the most important sequela of OCD?

Answer 27

Degenerative osteoarthritis

Question 28

T/F: Lameness is the first noticeable clinical sign of osteochondrosis

Answer 28

FALSE. Lameness is rarely severe enough to be noticed

Question 29

This is usually the primary clinical sign of osteochondrosis

Answer 29

Synovial effusion

Question 30

In nuclear scintigraphy, Technetium-99 acts as \_\_\_\_\_\_\_, so it gets incorporated into the bone about 2 hours after being given IV.

Answer 30

calcium

Question 31

Major collagen type in **fibrous connective tissue and bone** *Not* normally found in articular cartilage

Answer 31

Type 1 collagen

Question 32

Normal healthy collagen is collagen Type \_\_\_\_\_

Answer 32

2

Question 33

What is the most common location to see chip fractures in the carpus?

Answer 33

Distal Radial Carpal Bone

Question 34

T/F: Nutrition imbalances can cause degenerative osteoarthritis

Answer 34

TRUE

Question 35

Which 3 joints are most commonly affected by OCD in the equine?

Answer 35

1. Tibiotarsal (Tarsocrural) Joint (AKA HOCK) 2. Stifle 3. Fetlock

Question 36

The primary spongiosa is formed by ________ using calcified columns

Answer 36

Osteoblasts

Question 37

What are 2 methods used to resurface cartilage in the treatment of OCD in the equine?

Answer 37

Osteochondral dowel grafts Autologous chondrocyte transplantation (ACT)

Question 38

Osteochondrosis is a multifactorial disease. What 4 factors contribute to development of this disease?

Answer 38

Nutrition Growth Rate Heriditary Factors Trauma

Question 39

What is your diagnosis?

Answer 39

OCD- Flap formation

Question 40

How is OCD treated in the equine?

Answer 40

Rest IA medication Surgery- **Arthrotomy/Arthroscopy** Meds- Joint supplements and chondroprotectants

Question 41

Degenerative osteoarthritis is associated with \_\_\_\_\_\_ Calcium and \_\_\_\_\_\_\_\_\_ Phosphorus

Answer 41

**_decreased_** calcium **_increased_** phosphorus

Question 42

What location is most commonly affected by OCD in the STIFLE?

Answer 42

Lateral trochlear ridge

Question 43

What are the 5 categories of chondroprotective agents used to treat OCD?

Answer 43

Glucosamine Chondroitin sulfate Hyaluronic acid Polysulfated glycosaminoglycans (PSGAGs) Anti-inflammatories

Question 44

• Small-chain collagen that is found only in hypertrophic growth cartilage and the deep zone of adult articular cartilage * Unknown function * Considered a marker for hypertrophic cartilage

Answer 44

Type X collagen

Question 45

Cysts are most common at this location in the stifle joint

Answer 45

MEDIAL femoral condyle

Question 46

What is the sex predilection for degenerative osteoarthritis?

Answer 46

2:1 Males:Females

Question 47

\_\_\_\_\_\_ bone is responsible for supporting cartilage

Answer 47

Subchondral

Question 48

Bone and cartilage are formed by a process known as

Answer 48

Endochondral ossification

Question 49

Which 4 agents are used in gene therapy as treatment for OCD in equines?

Answer 49

IL-1 IL-like GF1 IRAP (IL1 receptor antagonist protein) PRP (platelet rich plasma)

Question 50

Which 3 Polysulfated Glycosaminoglycans (PSGAGs) are used as chondroprotectants in the treatment of OCD in the equine?

Answer 50

Myristol Cosequin Adequan

Question 51

Synovial effusion of the tarso-crural (aka tibiotarsal) joint is known as

Answer 51

BOG spavin

Question 52

Chip fractures of the carpus occur most commonly in which 3 locations?

Answer 52

Distal radial carpal bone (#1) Proximal intermediate carpal bone Distal lateral radius

Question 53

How is degenerative osteoarthritis (DJD- degenerative joint disease) diagnosed?

Answer 53

Nuclear **scintigraphy** with Technetium-99

Question 54

What 3 factors **inhibit** terminal differentiation of Chondrocytes?

Answer 54

Parathyroid hormone–related peptide * Transforming growth factor–β1 * Bone morphogenetic protein 7

Question 55

A joint disorder in which cracks form in the articular cartilage and the underlying subchondral bone due to blood deprivation in the subchondral bone. This loss of blood flow causes the subchondral bone to die in a process called avascular necrosis.

Answer 55

OCD- Osteochondritis Dissecans