VM 569 Equine Angular and Flexural Limb Deformities (Day 9, part 1)

What plane do angular limb deformities occur in? Flexural deformities?

-Angular - frontal plane -Flexural - sagittal plane

What structures do angular limb deformities primarily affect? Flexural deformities?

-Angular - osseous structures -Flexural - soft tissues

What is the growth periods for the carpus, tarsus, and fetlock? Why is this important?

-Carpus - 2-20 weeks -Tarsus - 2-16 weeks -Fetlock - 2-4 weeks -Must intervene surgically before the growth period ends

How are angular limb deformities diagnosed? (2)

-Clinically (standing or walking) -Radiographs

What is the surgical management of coffin joint contracture?

-Distal check ligament desmotomy - cut the check ligament (red) to release tension of the DDFT, allows the toe to come forward and down

Describe how shoeing and trimming can help treat angular limb deformities. (3)

-Extend the shoe on the opposite side of the limb -With fetlock varus - increase contact and friction on the lateral side to straighten the limb out -Manipulate bone growth

What are potential causes of flexural limb contracture? (3)

-Feed imbalances -Excessive growth -Physitis

What is the ideal time for transphyseal bridging for the fetlock and carpus/tarsus?

-Fetlock - 4 weeks -Carpus/tarsus - 4 months

When does the fetlock and carpus/tarsus stop growing?

-Fetlock - 9 months -Carpus/tarsus - 21 months

What is the ideal time for conservative treatment for the fetlock and carpus/tarsus?

-Fetlock - <2-3 weeks -Carpus/tarsus - <2-3 months

What is the ideal time for periosteal stripping for the fetlock and carpus/tarsus?

-Fetlock - <4 weeks -Carpus/tarsus - <4 months

Where is farriery applied in flexural limb deformities? Angular limb deformities?

-Flexural - applied to toe or heel -Angular - medially or laterally

What limbs is flexural laxity often seen in? What type of horse is it common in? How is it diagnosed?

-Hindlimbs -Common in premature or dysmature foals -Diagnosed clinically

Decrease how periosteal stripping is used to treat angular limb deformities.

-Lift the periosteum just above the growth plate on the "slow side" -Believed to cause growth acceleration of the growth plate on the "slow side"

What are the causes of angular limb deformities? (7)

-Nutrition -Genetics -Chrondrodysplastic breeds -Intrauterine malpositioning -Weak soft tissues surrounding the joint -Teratogenic ingestion of toxic plants -Idiopathic -Immaturity - lack of cuboidal bone ossification

What is flexural limb deformity? What is it caused by?

-Occurs in sagittal plane -Limb is abnormally flexed or extended -Caused by contracture or laxity of tendons/ligaments

What is the treatment for flexural limb laxity? (2)

-Often self correcting with restricted exercise -Caudal heel support and/or bandaged may be needed

What is "windswept"? What joints can it occur in? What is the treatment for this condition?

-One leg with varus and the other with valgus -Can occur in the tarsus or carpus -Usually corrects on its own within the first couple weeks of life

What are potential side effects of surgical correction of angular limb deformities? (2)

-Over-correction -Physitis

What horses commonly have angular limb deformities and incomplete ossification? What does this mean for the prognosis? What happens to the bones?

-Premature/dysmature foals -Prognosis is poorer than with angular limb deformities alone -Cuboidal bones become crushed resulting in permanent angular limb deformities

What is the treatment for angular limb deformities? (4)

-Stall rest and diet modification (mild cases) -Trimming and shoeing -Splint/casts -Surgery

At what age does coffin joint contracture usually occur?

1-4 months of age

What is the most common flexural limb deformity?

Coffin joint contracture ("club foot")

What is lateral deviation from the carpus called?

Carpal valgus

What is medial deviation from the fetlock called ?

Fetlock varus

True or False: Flexural deformities rarely require imaging/radiography.

True

True or False: Flexural limb contracture can cause dystocia if severe.

True

True or False: Flexural limb contracture may be present at birth or can be acquired.

True

True or False: Most foals are born with some degree of angular limb deformity.

True

When does hardware placed to correct angular limb deformities have to be removed?

When the limb is almost straight

What tendon is contracted in fetlock contracture?

Superficial digital flexor tendon

What is an angular limb deformity? (4)

-A conformational deviation of the limb in the front plane -Lateral deviation - valgus -Medial deviation - varus -NOT whole limb rotation

How does growth retardation help treat angular limb deformities? What methods are used?

-Aims at slowing down the growth on the "fast. longer side" Methods: -Transphyseal bridging - using 2 screws and a wire -Single screw

Why are radiographs used in angular limb deformities if we can diagnose the condition clinically? (2)

-Allows measurement of the angle of deviation -Allows you to see to other abnormalities (incomplete ossification of the cuboidal/carpal bones)

Describe how coffin joint contracture ("club foot") occurs. (2)

-Deep digital flexor tendon comes down the back of the leg and it attached to P3 -If the tendon is contracted (shorter), it drags P3 back and looks like the horse is pointing its toe

What nutritional imbalances can cause angular limb deformities? (3)

-Imbalance of calcium and phosphorus - should be 1:1 -Low copper -Low zinc

What is the treatment for fetlock contracture? (4)

-NSAIDs -Oxytetracycline -Controlled exercise -Surgical management

What is the treatment for coffin joint contracture? (6)

-Oxytetracycline - makes animal more lax -Therapeutic trimming -Trimming or rasping of the heel +/- toe extensions -NSAIDs -Controlled exercise -Surgical management

What are the two surgical options for angular limb deformities? (2)

-Periosteal stripping -Growth retardation

What can make angular limb deformities persist or worsen in foals born with them? (6)

-Poor limb conformation (other issues) -Improper trimming -Nutrition/over-nutrition -Excessive weight bearing -Injury -Excessive exercise

What is the surgical management of fetlock contracture?

-Proximal (superficial) check ligament desmotomy - cute this ligament to release the tension on the superficial digital flexor tendon