LA MS 6: Angular Limb Deformities Flashcards
Main Pediatric Conditions
Tendon laxity - weak flexor tendons
Flexural deformities - contracted tendons
Angular limb deformities - limb deviations
SDF Anatomy
Origin at the epicondyl of humerus
Inserts at P2
DDF Anatomy
Origin at epicondyl of humerus
Inserts at P3
SDF Check Ligament
Distal palmar aspect of radius
If you cut this, effectively lengthen musculotendinous unit of the SDF
DDF Check ligament
If cut this one, lengthen musculotendinous unit of DDFT
Tendon Laxity
Typically newborn foals
–congential»_space;> acq’d
HL»_space;> FL
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
Congenital Tendon Laxity
Etiology: musculotendinous weakened --prematurity --Primary systemic illness --lack of exercise Often will resolve on own Restrict exercise - protect from hurting self
Acq’d Tendon Laxity
Etiology - induced weakness
- -bandaging (avoid in foals!)
- -splinting
- -casting for extended periods
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!
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
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
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)
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***
Congenital Flexural Deformities Prog
Better if shorter duration and the limb can be straightened manually
Acquired Flexural Deformities
Uni or bilat Most common = fetlock, coffin jt Etiology --chronic pain in affected limb --rapid growth --> nutrient imbalances, genetics
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
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
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
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
