OCD in horses

Question 1

OCD/OC =

Answer 1

OSTEOCHONDRITIS DISSECANS

Question 2

what is the pathophysiology behind OCd?

Answer 2

There is a disturbance of cellular differentiantion in the growing cartilage.

• Persistent hypertrophic stage
• Improper vascular supply of the young cartilage.

Question 3

What are the different types of weaknesses in the cartilages?

Answer 3

• Flattening of the joint surface
• Cartilage flap without rad. changes
• Cartilage flaps free in joint
• Cartilage with subchondral bone changes
• OCD fragments free in joint

Question 4

What can be a result of OCD?

Answer 4

• Resorption
• Incorporation in joint capsule,
• Stays in joint -> Ossification, OCD fragments
• Riss in joint cartilage –> resorption -> SBC

Question 5

What are the causes of OCD?

Answer 5

1. Genetic predisposition (large breeds?) not in pony
2. Environmental influences
3. Nutrition - Imbalance in feeding / tak. imbalance
4. Endocrine factors
5. Biomechanic forces, Trauma

Question 6

What are the predilection sites of OCD? (in general)

Answer 6

Neck facet joints, shoulder, fetlock, femoropatellar joint, hock .

Question 7

What are the clinical forms?

Answer 7

• Osteochondrosis (OC)
• Osteochondritis dissecans (OCD)
• Subchondral Bone Cysts

Question 8

typical predielction sites of the hock joint:

Answer 8

DIRT / dist. Tibia cran. Intermed.
Lateral Talus Trochlea distal aspect
Medial Malleolus

Question 9

typical predielction sites of the stifle:

Answer 9

Lateral femoral trochlea

Question 10

typical predielction sites of the

Answer 10

Facet joints cervical region

Question 11

typical predielction sites of the fetlock joint:

Answer 11

Dorsal MCIII/MTIII Crista sagittalis

Question 12

typical predielction sites of the shoulder:

Answer 12

Caudal part of humerus head

Cavitas Glenoidalis, + caudodistal ridge of Scapula

Question 13

typical predielction sites of the shoulder:

Answer 13

Caudal part of humerus head

Cavitas Glenoidalis, + caudodistal ridge of Scapula

Question 14

Treatement of OCD?

Answer 14

• Wait if the foal are younger than 1 year.
• Conservative treatment
• Surgery

Question 15

Subchondral Bone Cysts , how does the cyst develop?

Answer 15

Different ways :

• Juvenile form similar to OCD.
• Tear in the weight-bearing cartilage.
• Pressure, enzymes develop a cyst.
• Mostly adult horses, but you can see it in fowls because of disturbance in bone formation.

Question 16

What can you find inside the cyst lining?

Answer 16

Fibrous tissue
Fibrocartilage
Necrotic bone

Sclerotic border around the cyst will develop which you can see on the Xray, more minerals around it.
Cloaca communication with the joint.

Question 17

What are the predilaction sites of the cysts?

Answer 17

1. Medial Femoral Condyle
2. Distal MCIII/MTIII (med. or lat. condylus or crista sagittalis)
3. Medial proximal Radius epiphysis
   - Distal phalanx
   - Scapula cavum glenoidale
   - White color on the X-rays

Question 18

What are the clinical signs of Subchondral Bone Cysts?

Answer 18

• Lame after work, better with rest
• More frequent: 6 M – 2 Y, But: you will find it also in older horses
• Lameness intermittent if not acute
• Receive if starts training again
• Sometimes acutely lame
• medial Femur condylus
• Distal MCIII
• Joint effusion not always present

Question 19

What are the treatment of Subchondral Bone Cysts?

Answer 19

Different surgical treatment regimens:

1. Steroid inj. Into the cyst – comes from human medicine in children
2. Extra-articular approach (drilling) and Parathormon Hydrogel (PTH)
3. Enucleation of the cyst inside lining
4. Defect filled out with TGF-1+ Ca activated thrombin +fibrinogen
5. Autologous Osteochondral Transplantation (Mosaicplasty)
6. Position screw through the cyst