ch.38bones.jts&connectivetissues

Question 1

Define physitis

Answer 1

developmental orthopedic condition in which there is a disturbance in endochondral ossification at hte physis or growth plate

Question 2

Many factors have been implicated as causes of physitis in horses, including

Answer 2

1. a genetic component for faster-growing horses and for specific conformation (such as an upright and pigeon-toed appearance)
2. Overweight foals
3. Growth spurts in foals
4. Intake of high levels of carbohydrates causing hormonal changes affecting the physis
5. Improper mineral balance (such as copper or zinc deficiencies)
6. Excessive or deficient calcium intake
7. Excessive exercise, especially on hard ground, causing strain on maturing cartilage

Question 3

Physitis common locations in horses

Answer 3

foals: 3 to 6 months
-metcarpal or metarsal growth plate (with or without prox physis of the first phalanx)

foals 8 to 24 months: physis of distal radius; less frequently distal physis of the tibia

Question 4

Changes radiographically of physitis

Answer 4

sclerotic, roughened physis with an irregular metaphyseal shape

Question 5

If physitis is allowed to continue what is a possible negative consequence?

Answer 5

the growth plate can close prematurely, leading to an irreversible angular limb deformity (usu a varus deformity d/t decreased growth on medial phsysis)

Question 6

What are treatment options for physitis?

Answer 6

-proper nutrition– balance of trace minerals (copper in particular)
-general reduction in energy– to slow growth rates
-exercise restriction (stall rest)
-NSAIDs as needed for pain

Question 7

When there is copper deficiency, physitis is a consequence through what mechanism?

Answer 7

the cartilage matrix weakens and microfractures occur

Question 8

Mares milk is very low in copper, so where do foals acquire their copper?

Answer 8

foals rely on hepatic stores gained during the last trimester of gestation

Question 9

Define Osteochondrosis

Answer 9

developmental orthopedic disease characterized by failure of or a defect in endochondrial ossification
–> lead to cartilage flaps osteochondral fragments or subchondral bone cysts