Angular Limb Deformities

Question 1

Define anglar limb deformities in foals.

____ is a lateral deviation.

____ is a medial deviation.

Answer 1

Angular limb deformities are postural demformities in the frontal plane of the limbs.

Valgus = Lateral

Varus = Meidal

Question 2

Describe the Normal posture of a horse.

TRUE / FALSE: Based on the description, the foal in the image has a bilateral valgus deformity.

Answer 2

NORMAL POSTURE:
o Draw imaginary line from tuber ischia through stifle → hock → fetlock → coffin should be straight
o Hoof distance apart between limbs
o For the hind limbs, draw an imaginary line from the tuber ischii distally with an imaginary 3rd hoof between to see how symmetrical and perpendicular to the ground. Most have this correct posture.

FALSE. Some foals have outward rotation. See donkey image for true valgus.

Question 3

What are the causes of angular limb deformities in foals?

Answer 3

• Periarticular laxity
• Incomplete ossification of carpal bones
• Hypothyroidism
• Limb conformation (overloading; physeal trauma, infection)
• Twins
• Multifactorial

Question 4

What are the ways to diagnose angular limb deformities in foals.

Answer 4

• Observation
• Radiographs
• Limb manipulaiton (tells you about laxity in joint)

Question 5

You take a radiograph of a foal and see this. What is happening in this carpus?

Answer 5

Incomplete ossification leading to rounded carpal bones. This contributes to instability of the joint space, resulting in either varus or vaglus deformities.

See normal radiograph on left. There should be some degree of increased joint space in young animals d/t the presence of more cartilage.

Question 6

What are the regions that can be affected with angular limb deformities?

Where is the pivot point usually located?

Answer 6

Regions: Carpus, Tarsus, Metacarpo/metatarsophalangeal joints (fetlock)

Pivot point Locations:

1. Growth plate (active growing animal)
2. Joint space

Question 7

Describe the process of finding the pivot point usuaing geometric analysis.

Answer 7

1. Cellulose acetate overlay is placed on radiograph
2. Trace bone outlines
3. Bisect long bone axis OR place lines throgh joint space
4. Measure deviation angle at each joint space where lines intersect (protractor)

Question 8

Conservative treatment of angular limb deformities includes stall rest, hoof trimming with the placement of _______ shoes, and external support (splint, cast).

Answer 8

Dalmer shoes

Question 9

What are the indications for conservative treatment of angular limb deformities in foals?

Answer 9

• Neonate
• 3 month + mild (<10 degrees) - exercise restriction