Angular and Flexural Limb Deformities Flashcards
What are some growth abnormalities that occur in foals?
Angular Limb Deformities
Tendon and Ligament Laxity
Flexural Deformity (Contracted Tendons)
What is the definition of an angular limb deformity?
Lateral or medial deviation to the long axis of the bone in the frontal plane
What is the name of the ALD described by a lateral deviation distal to the point pivot point?
Valgus
What is the name of the ALD described by a medial deviation distal to the point pivot point?
Varus
Who commonly gets ALD?
Foals - younger ones, all breeds and either sex
Which limb is the most common location for ALD?
Which site most common for ALD?
What is the most common defomrity?
Front limbs
Carpus, Fetlock, Tarsus
Carpal valgus, then fetlock varus
What causes congenital ALD?
Ligamentous Joint Laxity
-Worse on weight baring, shift while moving and windswept
Incomplete endochondral ossification of cuboidal bone (premature or dysmature)
What are some perinatal factors that contribute to ALD?
-Intrauterine mispositioning
-Over-nutrition of mare
-Hypoplasia of cuboidal bones
(Premature, dysmature, hypothyroidm, OC)
-Incomplete development MT/MC
What are some causes of acquired ALD?
-Asynchronous longitudinal growth of physis or physeal dysplasia (genetic, nutritional, physeal or physitis)
-Traumatic luxation or fracture of physis, epiphysis or crapal/tarsal bone
What factors should be considered in ALD?
-Inciting cause
-Physis growth
-Bone increase response to increase load
How do you go about evaluating ALD cases?
Signalment, HX, visual exam, physical exam, rads, is one present, has it changed over time, define it and what joints are involved
What type of history questions help with ALD?
When did they notice it? Has it worsened? Any lameness? Trimming?
What are some key parts of your ALD visual exam?
-Watch while standing and walking
-front and back/multiple limbs
-Multiple site on limb
-Estimate degree pivot point
-Lameness in limb or contralateral
-Look at mare
On your visual exam you notice the toe is deviated medially…what deformity will that most likely be?
(Fetlock) Varus
What is key when examining the joints and degree of angulation?
Need to be standing directly in front of the joint in question
What should be included in your physical exam?
Palpate joint laxity, observe angulation when flexed, evaluate hoof balance, palpate both limbs for heat, pain, swelling and crepitus
What should you observe on your radiographs?
Pivot Point
Mild: <5
Severe: >15
Is mild carpus valgus protective for carpal injury?
If so what does that make carpal varus?
Yes it is
Makes it bad
What may you find on a radiograph of an angular limb deformity?
Metaphysis - flaring and sclerosis
Growth Plate - indistinct physis, irregular width
Epiphysis - wedge shape, fracture lines
Cuboidal - abnormal shape, hypoplastic, collapsed, subluxated
MT/MC - shorter or wider joint space
Bone cotes - diaphyseal remodeling
Ulna/fibula - complete
What are treatment goals for ALD?
Improve the conformation
Halt worsening angulation
prevent DJD
Improve athletic performance
More intervention is needed if…
the foal is older and the deformity is more sever
What are some non-surgical treatments for ALD?
Stall rest and revaluate 2wks
Tube cast, splint or brace
Corrective trimming, hoof extension and shoeing
Prognosis ALD?
Hypoplastic cuboidal bones - poor athletic
Tendon and ligament laxity - good
What is sickle hock conformation?
Incomplete ossification of tarsal bones, collapse dorsal aspect of cartilage template, abnormal conformation, OA and lameness
If the horse has a varus deformity, which way should the extension go for correction?
Extension Lateral
(Extension medial for valgus)
How should you correctively shoe foals?
Glue ons, limit normal growth, day on day off, second set if needed, hoof nipper or rasp off
What are some surgical treatments for ALD?
-Periosteal transection and elevation
-Transphyseal bridging
-Wedge Ostectomy
What are some things to remember about transphyseal bridging?
Very effective, restrict exercise to prevent implant failure, second surgery to remove the implant, local infection and scarring, can overcorrect
When should you treat and when does the physis close of the following joints:
MCP/MTP:
Carpus:
Tarsus:
MCP/MTP: 30d, 120d
Carpus: 4m, 18m
Tarsus: 4m, 21m
How long should you wait to know if your conservative treatment is working?
no more than 3 weeks for MCP, no more than 3 months for carpus or tarsus
What is the rule on prognosis for ALD?
The more distal the pivot point the poorer the prognosis
How do you prevent ALD?
Owner education, monitor, proper feeding, look at mare and stallion conformation, foot trim and rasp on schedule, avoid excessive exercise
When should fetlocks be treated by?
2 months of age
What is the general process for fixing ALD?
Address inciting cause, restrict exercise, trim and rasp, hoof extension, transphyseal screw, periosteal transection and elevation
What are tendon and ligament laxity also known as?
Digital hyperextension deformities
Where are tendon and ligament laxity commonly found?
more in hind limbs
What is the cause of tendon laxity?
Lack of exercise, systemic illness, bandage or casting
What is a sign of tendon and ligament laxity?
No weight on toe, walk on heel bulb
How can you acquire a tendon and ligament laxity?
Hoof overgrowth
Bandaging or casting
What are some conservative ways that tendon and ligament can resolve?
Moderate exercise, trimming and rasping feet, shoe, light bandage to protect skin
Treatment for Tendon and ligament laxity?
Heel extension, controlled exercise, no splint or bandage
What is a flexural limb deformity?
length disparity between tendons and bones, tendon normal on ultrasound
Contracted tendons are
rare
Where does FLD or hyperflexion of a joint commonly occur?
DIJ, MCP, Carpus
Which limb do flexural deformities typically occur in?
Front
What causes FLD?
Congenital: uterine mispositioning, genetic, teratogen, disease of mare, locoweed, Sudan grass
What causes AFLD?
Growth disparity between bones, tendons and ligaments
Pain - flexion withdraw reflex (physis, OCD, septic arthritis, wounds, hoof pain, contralateral limb overload)
What is critical to assess when it comes to a foal with FLD?
Can it nurse
How do you know the horse has a DIJ FLD?
Walk on toe, cant put heel on ground, club foot, excessive toe wear
How do you know you have a metacarpophalangeal joint (fetlock) FLD?
Upright or knuckled over, DJD, reducible or non
How do you know you have a carpal FLD?
Buckling or flex at carpus
Treatment FLD?
Congenital: assist nursing, increase exercise, NSAID, Oxytet, Toe extension shoe, splint or cast, surgery
DJI - Hoof trim, rasp, lower heel, avoid trimming toe
Carpus- splint or cast
