Lecture 6: Angular limb deformities

Deviation in a frontal plan, can occur at the joint or growth plate

Angular

Deviation in a sagittal plane, contracture or laxity

Flexural deformity

When does skeletal ossification occur?

300 days

When does carpal and tarsal bones ossification occur?

The last 2-3 months of gestation

What causes perinatal factors?

• Premature birth

• Placentitis

  • Laxity of soft tissue structures

What bones are incomplete ossification of cubdoidal bones (perinatal) bones occur?

Crushing of incomplete cuboidal bones, carpus, hock

Incomplete ossification

treatment of incomplete ossification

exercise restriction (mild→ round pen/12 hrs per day, more→ Large stall confinement)

Exercise restriction of severe incomplete ossification

Cast/splints to transfere weight bearing from the carpus/tarsus

Possible complications of incomplete ossification?

Tarsal crush or fracture

Devitation of limb on the frontal plant

Angular limb deformity (AFD)

How do you diagnose ALD?

• Static evaluation

• Dynamic evaluation

• Palpation

  • Rads

Lateral deviation of the limb distal to the point of origin

Valgus

Medial deviation of limb distal to the point of origin

Varus

Toe aligned in the same direction as the other joints, entire limb is rotated outward.

Rotational ALD

How do you evaluate rotational ALD?

Must evaluate by aligning yourself with the foal’s foot

Windswept

Mild rads ALD

5 degrees

Moderate rad ALD

10 degrees

Severe rad ALD

>15 degrees

What are the most common locations of ALD?

Joint, metaphysis, epiphysis

True or false, most foals are born with the front legs rotated out. This changes in a couple of days.

True

When does the fetlock grow and close?

Grow: 0-2 months

Close: 6 months

When does the carpus grow and close?

Grow: 0-6 months

Close: 22-36 months

When does the hock growth and close?

Grow: 0-4 months

Closure: 17-24 months

What foot should you trim for valgus?

Lower lateral aspect of hoof

What part of the foot do you trim with varus?

Lower medial aspect of hoof

Where should you apply acrylic for valgus?

Medial

Where should you apply acrylic for varus?

Lateral

What are the benefits of periosteal strip?

Encourages growth and no over correction

What joints are commonly corrected for periosteal strip?

Fetlock and carpus

What are uncommon joints for periosteal strip to be performed for?

Tarsus

Slows the growth of the faster growing side of the growth plate. 4.5 mm cortical bone screw w/figure-eight wire.

Transphyseal briding

Can the transphyseal bridging implants stay in forever?

No must be removed after correction

How can you surgically retard the growht?

Single transphyseal screw

Which joint has the best prognosis?

Carpus (80-85%)

What type of deviation is associated with angular limb deformities?

a) Deviation in the sagittal plane.

b) Deviation in the frontal plane.

c) Contracture.

d) Laxity

b) Deviation in the frontal plane.

Incomplete ossification primarily affects which bones in foals?

a) Long bones

b) Cuboidal bones of the carpus and hock

c) Skull bones

d) Ribs

b) Cuboidal bones of the carpus and hock

Which of the following is a potential cause of angular limb deformities in foals?

a) Excessive exercise

b) Premature birth

c) High-protein diet

d) Viral infection

b) Premature birth

What is a valgus deformity?

a) Medial deviation of the limb distal to the point of origin.

b) Lateral deviation of the limb distal to the point of origin.

c) Rotational deviation of the limb.

d) Deviation in the sagittal plane.

b) Lateral deviation of the limb distal to the point of origin.

At what point of gestation do bones become visible on a radiograph?

a) 150 days

b) 200 days

c) 300 days

d) 330 days

c) 300 days

What is the recommended treatment for mild immaturity in foals with incomplete ossification?

a) Strict stall confinement

b) Exercise restriction with round pen or small paddock for 12 hours/day

c) Application of full limb casts

d) Surgical correction

b) Exercise restriction with round pen or small paddock for 12 hours/day

When evaluating angular limb deformity, with what should you align yourself?

a) The foal's head

b) The foal's foot

c) The foal's carpus

d) The foal's point of origin of deviation

b) The foal's foot

What is the success rate for correcting carpal angular limb deformities7?

a) 27%

b) 50%

c) 80-85%

d) 95%

c) 80-85%

What is the closure time for the distal metacarpus/tarsus growth plate5?

a) 0-2 months

b) 0-4 months

c) 0-6 months

d) 22-36 months

a) 0-2 months

What is the purpose of a periosteal strip in the surgical treatment of angular limb deformities?

a) To slow growth

b) To encourage growth

c) To fuse the joint

d) To stabilize the bone

b) To encourage growth