Typically newborn foals --congential >>> acq'd HL >>> FL

Etiology - induced weakness - -bandaging (avoid in foals!) - -splinting - -casting for extended periods

LA MS 6: Angular Limb Deformities Flashcards by Ella Pittman

Main Pediatric Conditions

Tendon laxity - weak flexor tendons
Flexural deformities - contracted tendons
Angular limb deformities - limb deviations

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SDF Anatomy

Origin at the epicondyl of humerus

Inserts at P2

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DDF Anatomy

Origin at epicondyl of humerus

Inserts at P3

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SDF Check Ligament

Distal palmar aspect of radius

If you cut this, effectively lengthen musculotendinous unit of the SDF

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DDF Check ligament

If cut this one, lengthen musculotendinous unit of DDFT

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Tendon Laxity

Typically newborn foals
–congential&raquo_space;> acq’d
HL&raquo_space;> FL

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Tendon Laxity CS

Not weight bearing on toes, walking on heel bulbs
Severe cases rest fetlocks on the ground
Animals get get concussion early forces, contusions - IFXs of heel bulbs or fetlocks

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Congenital Tendon Laxity

Etiology: musculotendinous weakened 
--prematurity 
--Primary systemic illness 
--lack of exercise 
Often will resolve on own
Restrict exercise - protect from hurting self

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Acq’d Tendon Laxity

Etiology - induced weakness

-bandaging (avoid in foals!)
-splinting
-casting for extended periods

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Tendon Laxity Tx

Trim heels flat –> elim rocker effect
Heel extension shoes (more severe cases)
–provide palmar/plantar support
–protect fetlocks and heel bulbs from trauma
–Just be careful about the coronary band: can induce damage if squeezed too tightly or glued on
Exercise
Prog - favorable
Be sure to protect fetlocks and heel bulbs from contusions!

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Why Injuries/erosions on distal limb bad

Difficult to tx - no place to come to or contract in distal limb
Can turn sour very quickly: IFX of sesamoid bones, jt IFX

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Flexural deformities

“Contracted tendons”
Persistent hyperflexion of jt
–tendons functionally too short compared to bone
FL > HL
–typically only 1 jt: coffin, fetlock or carpus
Congenital or acquired

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Congential Flexural Deformities

Etiology = multifactorial 
--Uterine malpositioning 
--Genetics 
--Idiopathic 
Fetlock and carpal deformities = most common 
--Fetlock: SDF, DDF
--Carpus: combination and carpal fascia 
(Club foot = acquired)

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Congential Flexural Deformities Tx

Increase exercise 
Oxytet 
NSAIDS 
Splints during the day 
Toe extension shoes 
Sx in severe cases 
***MUST BE ABLE TO STAND AND NURSE***

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Congenital Flexural Deformities Prog

Better if shorter duration and the limb can be straightened manually

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Acquired Flexural Deformities

Uni or bilat 
Most common = fetlock, coffin jt 
Etiology
--chronic pain in affected limb 
--rapid growth --> nutrient imbalances, genetics

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Acq’d flexural deformities coffin jt

Contracture of DDFT "club foot"
Most developing btw 4 weeks and 4mo 
Stage 1: dorsal hoof wall less than vertical 
--can fix at this stage 
Stage 2: dorsal hoof wall over vertical 
--prog poor for athletic performance

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Tx Acq’d Flexural Deformities of Coffin Jt

Dietary changes 
Exercise 
Toe extension shoes 
NSAIDS, sometimes oxytet 
Sx: distal check ligament desmotomy, may need DDF tenotomy for stage 2

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Sx for Acq’d Flexural Deformities - coffin jt

Be careful when doing this sx that doesn’t cut the wrong structure!!!

Check much bigger than SDF or DDF in live horse!
Prognosis guarded for stage 2 cases

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Acq’d Flexural Deformities: fetlock

Contracture of SDF
Knuckle forward at fetlock with the hoof in normal alignment
Most develop btw 9mo and 2yr
Most often both SDFT and DDFT involved

Acq’d Flexural Deformities: fetlock tx

Dietary changes
Exercise
Toe extension shoes
NSAIDS, sometimes oxytet
Sx: prox +/- distal check ligament desmotomy, rarely SDF tenotomy
Splinting of limb best in hospital setting

Acq’d Flexural Deformities: fetlock Prog

Variable - jt capsule fibrosis

If do sx in show horses, will always have slight cosmetic defect

Angular Limb Deformities

Lateral or medial deviation of the limb
–varus = medial deviation of limb below jt
–valgus = lateral
Congenital or acquired

Acquired Angular Limb Deformities

Often will see in a horse with altered WB for so long that varus from increased WB on good leg

Angular Limb Deformities - who

``` Rare in ponies Age: foals, usually quite young Breed: all, esp those with rapid growth Limb: FL > HL Sites: carpus, fetlock, tarsus ```

Angular Limb Deformities Most Common Deformities?

Carpal valgus, fetlock varus

Angular Limb Deformities Need to Know

``` Is a deformity present? Has the deformity changed over time? What is the deformity? What jt(s) involved? What should you do - act or wait and see? ```

How to Examine Foals

Look at foal from the front Palpate limb - can you correct it? Examine the foot Watch the foal walk

Looking at foal from the front

Align yourself with the toe of the foot Ask where the knee is and the rest of the limb? --look for wounds on medial aspect of carpus if very knock-kneed

Palpate Limb

Joint Laxity Can the deformity be manually corrected? Heat, pain swelling? --also check opposite limb

Examine foot

Is hoof worn more on one side? Rasp should be on your hand Make it smooth and then watch it walk again

Watch Foal Walk

``` Don't forget to look at mom too! Watch foal travel Look for: --multiple limb involvement --lameness in opposite limb --similar deformities in the mare ```

Congenital Angular Limb Deformities

Present @ birth, may correct without tx --foals start out a little carpus valgus If severe (>15 degrees) or not improving within 5-7d, tx indicated

Congenital Angular Limb Deformities Etiology

Intrauterine malposition Joint laxity - prematurity Incomplete ossification of cuboidal bones (normally 300d gestation)

Congenital Angular Limb Deformities: different from windswept foals

Windswept foals have both HL curving in the same direction --ligament and tendon laxity --self correct in a few weeks Tx: controlled exercise

Acq'd Angular Limb Deformities

Born straight but go crooked within weeks or months of birth Etiologies --growth plate injury or physitis --lame in CL limb --Overnutrition that leads to rapid growth --genetic predisposition to rapid growth

Angular Limb Deformities Dx

``` Visual and PE --Lameness in opp limb --Mare's legs RADS --long plates 7x17 --DP (carpus), lateral (Tarsus) --Determine degree and pivot pt ```

Incomplete Ossification

Premature/dysmature foals Usually severe deformity --carpus valgus --sickle hocked

Incomplete Ossification tx

Sleeve (tube) casts --ends at fetlock ie doesn't include foot --Max 14d Early tx essential because abN ossification pattern occurs

Angular Limb Deformities Tx - Conservative

``` Mild cases (5-10degrees) or early in physeal growth --rest, trimming, shoes ```

Angular Limb Deformities Tx - Sx

Moderate to severe cases or at end of physeal growth | Periosteal transaction, transphyseal bridging, single transphyseal screw, wedge osteotomy

Other Angular Limb Deformities: Conservative Tx

Corrective trimming: lower the wall toward which hoof deviating --ex: if turned out, trim outside wall Shoeing: place extension on side of hoof that wearing out of most --ex: if turned out, inside (medial) extension

Other Angular Limb Deformities: Conservative tx - fetlock varus

Trim inside | Outside extension

Angular Limb Deformities Sx: Periosteal Bridging

Performed to stimulate growth - on concave side, prox to physis Radius - ulnar osteotomy +/- transphyseal bridging on opposite side

Angular Limb Deformities Sx: Transphyseal bridging

``` Performed to slow growth --on convex side of deformity --screws prox and distal to physis --figure of 8 wires around screws Remove implants when straight!!! ```

Angular Limb Deformities Sx: Transphyseal Screw

``` Performed to slow growth --convex side of deformity --single lag screw across physis --improved cosmetic appearance vs bridging Remove implants when straight ```

Angular Limb Deformities Alpacas

Normally carpus valgus - sx if only a true deformity

Angular Limb Deformities Prognosis - incomplete ossification

Good if treated early | Guarded if treated late or have crush injuries

Angular Limb Deformities prognosis - other angular limb deformities

Severe (>15 degrees) = fair if early Lower jt = fair if early, generally less success DT short time for correction End of physeal growth = less success