Equine Orthopedic Diseases Flashcards
What are the major components of cartilage
Proteoglycans
Water (70-80%)
Dry Weight
50% type 2 collagen
35% proteoglycans
50% of the dry weight of cartilage is
type 2 collagen
35% of the dry weight of cartilage is
proteoglycans
What are we treating with equine osteoarthritis
1) Mechanical stress
2) Inflammation
3) Decreased SF viscosity
4) Cartilage breakdown
How does synovial fluid viscosity change with osteoarthritis
it becomes more fluid (decreased viscosity)
What is the pathogenesis of equine osteoarthritis
1) Synoviocytes are subjected to trauma and inflammation
2) Release IL-1, TNF-a, Metalloporteinases, Prostaglandins
3) Act on cartilage, more inflammatory mediators
4) Chondrocytes produce more mediators like PGE2 and Metalloproteinases leading to matrix degradation
Self-sustaining process
What inflammatory mediators are produced by synoviocytes during equine osteoarthritis
IL-1
TNF-a
Metalloproteinases
Prostaglandins
What inflammatory mediators are produced by chondrocytes during equine osteoarthritis
PGE2
Metalloproteinases: Stromelysin and Collagenase
-Leads to matrix degradation
What are the stages of equine joint disease
1) Synovitis: Synovial inflammation + deteriorating joint fluid
2) Degenerative Joint Disease: cartilage changes + joint capsule fibrosis
3) Osteoarthritis: bony changes
With equine joint disease, where is the stage of no return
Once synovitis begins to develop into degenerative joint disease (cartilage changes and joint capsule fibrosis)
Inflammation of synovial and deteriorating joint fluid (more watery)
early stage of joint disease
Synovitis
cartilage changes and joint capsule fibrosis,
past the point of no return
Degenerative joint disease
bony changes seen after degenerative joint disease
osteoarthritis
How do you diagnose equine osteoarthritis
1) Lameness exam first
2) Radiographs
3) Nuclear scintigraphy- turn over of bone (remodeling areas are darker)
4) Ultrasound
5) MRI- hoof and cartilage (only distal to carpus/tarsus)
6) Exploratory arthroscopy- see cartilage lesions well that radiographs might not pick up
How do you tell what areas are undergoing active remodeling in nuclear scintigraphy
darker areas
In horses, you can only use MRI if the lesion is
distal to the carpus/tarsus
You have a 5yo QH gelding presenting for a left forelimb lameness.
Positive to distal limb flexion, all other flexions negative
Lameness improved 80% with a basisesamoid block
What imaging modality would you perform first?
Radiographs to look for bony lesions
What are goals of equine OA therapy
1) Decrease inflammation- soft tissues and cartilage
2) Alleviate pan
3) Lubricate joint
4) Restore normal environment
5) Slow down disease progression
6) Remove inciting cause
What should you consider when chooding OA therapeutic choices
1) Is it joint involved
2) Stage of OA
3) Current and intended use
4) Age
5) Regulations
6) Cost
7) Response to therapy
What do chondroprotective agents do
Support joint structure and function
1) Normalize synthesis of matrix components
2) Decrease matrix degradation
A polysulfated glycoaminoglycan used IM to systemically treat OA in horses
Adequan
What are the different systemic therapies for OA in horses
1) NSAIDs
2) Polysulfated Glycosaminoglycan (Adequan)
3) Oral, slow acting agents like Cosequin and Glycoflex
What is the mechanism of action of NSAIDS
inhibits COX’s conversion of arachidonic acid to prostaglandin
COX-1: inflammation
COX-2: Homeostatic functions- GI tract, renal tract, platelet function, macrophage differentation
What COX is responsible for inflammation
COX-2 induced
What COX is responsible for Homeostatic functions- GI tract, renal tract, platelet function, macrophage differentation
COX-1 constitutive
What equine NSAIDs inhibit both COX-1 and COX-2
1) banamine (flunixin meglumine)
2) Bute (Phenylbutazone)
What equine NSAID inhibit primarily COX-2
Equioxx (Firocoxib)
COX-1 sparing NSAID
What is the COX-1 sparing NSAID used in horses
Equioxx (Firocoxib)
What NSAID is safest for use in horses
Equioxx (Firocoxib)
Safer but more expensive
-efficacy equivalent to phenylbutazone
Reduced risk of gastric ulceration
What NSAID in horses has a reduced risk of gastric ulceration
Equioxx (Firocoxib)
still has some risk, does inhibit some of COX-1 but it primarily on COX-2
What does Adequan do
it is composed of chondroitin sulfate- 1) stimulates the production of hyaluronic acid from synoviocytes
2) Increases synthesis of proteoglycans and collegen by chondrocytes
3) Inhibit metalloproteases, cathespins, and other degradative enzymes
What are the three effects of polysulfated glycosaminoglycan (Adequan)
1) stimulates the production of hyaluronic acid from synoviocytes
2) Increases synthesis of proteoglycans and collegen by chondrocytes
3) Inhibit metalloproteases, cathespins, and other degradative enzymes
What are the different intra-articular therapies you can use for OA in horses
1) Corticosteroids: Anti-inflammatory and chondroprotective
2) Hyaluronan: chondroprotective
3) Biological therapies
What is the mechanism of action of corticosteroids in equine OA tx
inhibits the phospholipase A2 conversion of phospholipids to arachidonic acid
this blocks both the cyclooxygenase pathway and the lipoxygenase pathway
*Works a step earlier than NSAIDs
What are the effects of giving corticosteroids for equine OA ?
1) Potent inhibitors of IL-1 and TNF-a (also inhibit IL-1 synthesis by synovial lining cells)
2) Reduce matrix MMP activity
3) Inhibit synthesis of MMP activators (plasminogen activator or plasmin)
4) Decrease WBC migration, fibrin deposition
5) Stabilize enzymes (Stromelysin)
What are the detrimental effects of corticosteroids on cartilage
1) GAG depletion
2) Suppressed collagen and hyaluronic acid synthesis
3) Laminitis
4) Steroid arthropathy
T/F: When doing joint injections in horses, the type of corticosteroids does not matter
False- it really matters
What are the three primary corticosteroids used for equine joint injections
1) Bethamethasone- potent, medium duration, 20-40 mg/joint, 100mg total
2) Triamcinolone acetonide (Vetalog) medium length of intra-articular half-life (1-5days), 6-9mg/joint (18mg total)
3) Methylprednisolone acetate (Depomedrol): long acting (intra-articular half life is one month), 40-60 mg/joint, 120 mg total, Synovial flare
NO healthy joints or high motion joints
Triamcinolone acetonide (Vetalog)
medium length of intra-articular half-life (1-5days), 6-9mg/joint (18mg total)
You should never put Methylprednisolone acetate (Depomedrol) in what joints *
1) Healthy joints
2) High motion joints
3) Never as a first line treatmnet
Severely detrimental affect
typically only SI
Methylprednisolone acetate (Depomedrol)
long acting (intra-articular half life is one month), 40-60 mg/joint, 120 mg total, Synovial flare
NO healthy joints or high motion joints
Betamethasone
potent, medium duration, 20-40 mg/joint, 100mg total
What corticosteroid formulation has the longest halflife when used in equine joint injections
Methylprednisolone acetate (Depomedrol)
A 15yo QH gelding has a right hindlimb lameness with marked tarsocrural joint effusion
Hx of repeated Intra-articular depomedrol injections
Has previously had radiographs and ultrasound of the RH, What do you do next
Diagnostic Arthroscopy
What are complications of corticosteroid IA injections
1) Joint “Flare” Acute inflammation to medication formulation
-Heat, pain, swelling, lameness
-8-24 hours after injections
2) Joint infection- signs not obvious immediately following injections
-Infections following steroid injections can be devastating
Do joint infections or joint “flare” inflamamtion occur sooner
Joint “Flare” is acute inflamamtion
Why are maintaining low doses of corticosteroids important
chondroprotective properties without marked effects on chondrocytes
You are seeing a 10yo warmblood sport horse for lameness
He is a grade 3/5 left hindlimb lame and you localize the lameness to the distal hock joint
The owner is keen to medicate with corticosteroids.
What do you recommend
inject each joint (4 in total) with 4mg triamcinolone
only comes out to 16mg total and you should be under 18mg total
What is the max dose of Triamcinolone Acetonide (Vetalog)
6-9mg/joint
18 mg total (but 20-30 mg ok)
What is the max dose of Depomedrol (Methylpredinisolone acetate)
120 total
40-60 mg/joint
What is the max dose of Betamethasone
20-40 mg/joint
100 mg total
non-sulfated GAG that is synthesized by Type B synoviocytes and chondrocytes
important component of the articular cartilage matrix
-backbone of the proteoglycan aggregate in the ECM
-Synovial fluid viscosity
Hyaluronan
Hyaluronan is produced by
Type B synoviocytes and chondrocytes
Sodium hyaluronan is best for what in horses
treatment of early OA
-acute synovitis
but corticosteroids still much better and work synergistically
Sodium hyaluronan has enhanced effects when combined with
low dose steroids
What is the mechanism of action of sodium hyaluronan
unclear
1) boundary lubrication
2) Steric exclusion of particles
3) Anti-inflammatory effects
For Sodium hyaluronan, how do you know what product to choose
it needs to be >500,000 Daltons
What are commonly used sodium hyaluronans used
1) Hylartin V (3.5,000,000)
2) Hyvisc (1,000,000)
3) Legend (500,000)
How is arthtroscopy both diagnostic and therapeutic
it can help identify cartilage defects that cannot be seen on radiographs
it can also be used to debride wounds
What are topical therapies used to treat equine OA
Liposomal NSAID cream: liposomes hold higher concentration at the site of inflammation
leads to significant improvement of lameness
disease modifying:
1) Improved gross cartilage staining
2) Improved total articular glycosaminoglycan content
T/F: Liposomal NSAID creams (diclofenac) have signficant improvement in lameness when used in horses with OA
True
Topical therapies like liposomal NSAID cream have what disease modifying effects in OA in horses
1) Improved gross cartilage staining
2) Improved total articular glycosaminoglycan content
Advanced therapies in equine OA
Il-1ra/APS (Prostride)
Stem cells
PRP
Most common devleopmental orthopedic disease in foals
Osteochondrosis dissecans
Common developmental orthopedic diseases in foals
1) Osteochondrosis - dissecans + subchondral bone cysts/cystic lesions
2) Physitis
3) Angular limb deformities
4) Flexural limb deformities
5) Some cervical vertebral malformation
6) Juvenille OA (hock and pastern)
conformational deviation of the limb in the frontal plane
angular limb deformities
conformational deviation of the limb in the sagittal plane
flexural limb deformities
-soft tissues holding limbs in position
What happens when the physis matures too quickly
contracted tendons- bones grow too fast and the soft tissues cant keep up
physis becomes inflamed
physitis
physis has abnormal mechanical pressure
angular limb deformity
epiphysis has abnormal ossification
Osteochondrosis dissecans
What factors lead to developmental orthopedic diseases in foals
1) Genetic predisposition/rapid growth
2) Nutritional factors (excesses or imbalances)
-High energy (High CHO)
-Mineral imbalances (high Ca, DE, & P)
-Trace minerals (Cu & Zn)
3) Endocrine imbalances (TH, insulin
4) Trauma
High levels of what mineral is correlated with OCD lesions in foals
phosphorus (like 4x the value)
the most significant skeletal disorder of growing horses
-OCD
-Subchondral bone cysts/cystic lesions (CBC/SCL)
What are the most common sites to see OCD lesions in foals
1) Fetlock joint
2) Tarsocrural joint
-distal intermediate ridge of tibia
-lateral trochlear ridge
-medial malleoulus of tibia
3) Femoral-Patellar joint
-Lateral trochlear ridge
-Medial femoral condyle (bone cyst)
What is the pathogenesis of osteocondrosis in foals
1) Disruption of nx endochondral ossification
A)Cleft formed in thickened cartilage (OCD)
OR
B) Entrapped cartilage leading to subchondral cyst formation
What are the most common sites for an OCD lesion of the tarsocrural joint in the foal
-distal intermediate ridge of tibia
-lateral trochlear ridge
-medial malleolus of tibia
What are the most common sites for OCD lesion of the femoropatellar joint in the foal
-Lateral trochlear ridge
-Medial femoral condyle (bone cyst)
What are the two fates when there is a defect in endochondral ossification
A) Cleft formed in thickened cartilage (OCD)
OR
B) Entrapped cartilage leading to subchondral cyst formation
What are the clinical signs of OCD in the stifle in horses
young horse, often fast growing
joint effusion
variable lameness present
often bilateral involvement
Lateral trochlear ridge ridge, medial trochlear ridge
Are OCD lesions of the equine stifle typically bilateral or unilateral
bilateral
How do you treat stifle OCD in horses
Preventative: nutrition evaluation if many cases are involved
Conservative: rest, re-radiograph
Surgical: Arthroscopy- debride, inject, pin lesion
Prognosis is favorable
You have a horse with a lateral trochlear ridge OCD lesion. What do you recommend for tx . Horse is 2yo
Arthroscopic removal
older horse, wont heal on its own
How do you treat Hock OCD lesions in the horse
Preventative: nutrition evaluation if many cases are involved
Conservative : Small lesions without effusion
Surgical: Arthroscopy to debride lesion
prognosis is favorable
T/F: Subchondral bone cysts have lots of effusion compared to OCD lesions
False- minimal effusion
Where in the equine stifle are subchondral bone cysts almost always located
almost always the medial femoral condyle
Subchondral bone cyst of equine stifle
minimal effusion
variable lameness
almost always medial femoral condyle
physitis
lameness
dx: radiographs
assess/change diet
rest/limit exercise
can lead to angular limb deformities
What causes congenital flexural deformities in foals
1) Teratogenic agents
2) Intrauterine positioning
3) Genetic predisposition - too rapid of growth
What causes acquired flexural deformities in horses
1) Nutritional - too rapid of growth
2) Trauma
3) Infectous polyarthritis
often involve the DIP of fetlock
all lead to pain and altered weight bearing thus causing the flexural deformity
Acquired flexural deformities are caused by nutrition, trauma, or infectious polyarthritis, they often involve which joints
1) DIP
2) Fetlock (MCP >MTP)
Flexural deformities of the DIP joint in horses typically develop between
Birth to 4 months of age
Flexural deformities of the MCP joint in horses typically develop
later, when they are yearlings ~18 months age
Flexural deformities is more common in the MCP or MTP?
MCP
How do you treat flexural limb deformities in horses
-Evaluate nutrition, control growth rate
-Control painful stimuli (NSAIDs)
-Medical treatment: Oxytetracycline and Splinting
-Surgical intervention (>180 degrees)
With flexural limb deformities in horses, when do you recommend immediate surgical intervention
the the angle is greater than >160 degrees, especially MCP
How do you medically treat flexural limb deformities
-Control painful stimuli (NSAIDs)
-Medical treatment: Oxytetracycline and Splinting
Oxytetracycline IV only helpful first few weeks of life (only 1-2 doses)
You are presented with a newborn foal with carpal contracture meaning it cannot stand without assistance
What are your initial treatments in regards to orthopedic disease?
Oxytetracycline and splint from ground to elbow
Oxytetracycline is only helpful in treating flexural limb deformities if
IV only helpful first few weeks of life (only 1-2 doses)
What is the most likely cause for a newborn foal’s contracted limbs?
Uterine malpositioning
deviation from the normal axis referred to as valgus or varus deformity
angular limb deformities
lateral deviation of the limb distal to the site of the deformity
valgus
medial deviation of the limb distal to the site of the deformity
varus
What might cause congenital angular limb deformities in horses
1) incomplete ossification of cuboidal bones or epiphyses
2) Ligament laxity- medial, lateral collateral ligaments of joints
What is important for normal physeal growth
load
delayed or defective physeal growth results in
ALD- most originate at the physis
incomplete ossification can lead to
crushing of the cuboidal bones and uneven growth
need to maintain equal weight bearing until ossified
in a foal angular limb deformities, why might you not want to cast hindlimbs
Although effective in making sure the foal bears weight evenly, they can luxate their capital femoral physis really easily
just use splints instead
Acquired Angular limb deformities in horses can be due to
1) Nutritional imbalance
2) Abnormal loading of the physis
3) Trauma
How do you rule out ligament laxity
move the limb deformity and if you can return it to normal position, it is soft tissue and not bone
of you cant, rule out ligament laxity
How do you diagnose ALD in horses
Radiographs are key
Normal = Angulation of 4 degrees
Radiographic examination of affected joints must be done early in the course of the disease
What is normal angulation of equine limb
4 degrees, ideally 5-6 degrees as a little of valgus is protective
Conservative treatment w ALD
-Exercise restriction/stall rest
-Correcting trimming +/- shoeing
-Minimize abnormal biomechanical forces- Splints if ligament laxity/delayed ossification
Re-evalaution needed in 2-3 weeks
How often should you re-evaluate foals with ALD *
2-3 weeks
Corrective trimming for valgus
put extension of medial side of foot
Corrective trimming for varus
put extension of lateral side of foot
surgical treatment of ALD must be done
before the physis close
-aim is to slow down growth
-contralateral growth acceleration procedures such as periosteal stripping rarely used- outcomes equivalent to stall rest
-Transphyseal screw
-Transphyseal bridge
What is the goal of ALD surgical treatment
Slow down growth
must be done before physis close
Surgical tx of ALD
-must be done before physis close
-aim is to slow down growth
-contralateral growth acceleration procedures such as periosteal stripping rarely used- outcomes equivalent to stall rest
-Transphyseal screw
-Transphyseal bridge
When does the distal radius/ tibia growth plate close
1-1.5 years = when little to no growth continues
Best therapeutic window within 4-6 months
When is the best therapeutic window for distal radius/tibia ALD
Best therapeutic window within 4-6 months
1-1.5 years = when little to no growth continues
When is the best therapeutic window for distal metacarpus/metatarsus ALD
within 3-4 weeks
12-14 weeks = when little to no growth continues
When does the the distal metacarpus/metatarsus growth plate occur
12-14 weeks
therapeutic window is within 3-4 weeks
What is a transphyseal bridge for ALD tx
a surgery to bridge the side that you want to slow down growth
allows the other side to catch up
For Valgus= turning laterally = medial side growing faster = bridge the medial physis
For valgus, what side do you want to do the transphyseal bridge on
For Valgus= turning laterally = medial side growing faster = bridge the medial physis
For varus, what side do you want to do the transphyseal bridge on
For varus = turning medially = lateral side growing faster = bridge the lateral physis
What are the differential diagnoses for severe lameness in horses
-Fracture
-Infection in a confined space (hoof abscess, septic synovial structure- joint, tendon sheath or cellulitis
-Laminitis
-Severe soft tissue injury (destabilizing tendon/ligament injury or joint luxations)
How does septic arthritis / tenosynvotis occur in horses
Foals- hematogenous
1) Failure of passive transfer
2) Patent urachus
Multiple limbs can be affected
Adults
1) Traumatic (wound)
2) iatrogenic - joint injection (0.4% incidence)
How might a foal get septic arthritis / tenosynvotis
1) Failure of passive transfer
2) Patent urachus
How might an adult horse get septic arthritis / tenosynvotis
1) Traumatic (wound)
2) iatrogenic - joint injection (0.4% incidence)
T/F: Adult horses with arthritis / tenosynvotis are febrile
False - only foals
T/F: arthritis / tenosynvotis only occurs in single joint in adult horses
True, unless injury occurs near multiple synovial structures
foals commonly have multiple limbs affected and can be febrile
Septic arthrtis risk factors in adult horses
recent intra-articular injection
recent joint sx
puncture wounds/ lacterations near joints
Septic arthritis risk factors in foals
1) Failure of passive transfer
2) Sepsis
3) Umbilical infection
4) Respiratory infection
5) Gastrointestinal (colitis)
What are exam findings of horses with septic arthritis
1) Moderate to severe peri-articular swelling/edema
2) Grade 4-5/5 lameness unless joint is open and draining
3) Pain
4) Heat
5) Fever (foals only)
How do you diagnose septic arthritis in horses **
1) Arthrocentesis - cytology (degenerative neutrophils +/- intracellular bacteria)
Fluid exits from wound after distension
2) Culture and sensitivity of synovial fluid and blood (foals)
3) Radiographs- lysis/erosion
4) Ultrasound- particles in fluid
5) Point of care analyzers of synovial fluid - Serum amyloid A and lactate
if you get a negative culture of synovial fluid, can you rule out joint infection in horses?
NO- bacterial likes to be in synovial membrane so sometimes they arent cultured within the fluid
What should normal equine synovial fluid look like
pale (straw colored) yellow
What does septic arthritis synovial fluid look like
yellow to orange
What is the viscosity of normal equine synovial fluid
high viscosity
What is the viscosity of septic equine synovial fluid
low- lost with OA and septic arthritis
What is the turbidity of normal equine synovial fluid
transparent /clear
What is the turbidity of septic equine synovial fluid
turbid, opaque
What is the total protein of normal equine synovial fluid
<2.5 g/dL
What is the total protein of septic equine synovial fluid
> 4g/dL
What is the nucleated cell count of normal equine synovial fluid
<1000 (x10^6/uL)
What is the nucleated cell count of septic equine synovial fluid
> 30,000 x 10^6 /uL
What is the WBC differential of normal equine synovial fluid
<10% neutrophils (mostly mononuclear cells)
What is the WBC differential of septic equine synovial fluid
> 90% neutrophils (degenerate of non-degenerate)
What are the characteristics of normal equine synovial fluid *
Pale (straw colored) yellow
Transparent/Clear
High Viscosity
<2.5g/dl protein
<1000x10^6 nucleated cell count
<10% neutrophils (mostly mononuclear cells)
What are the characteristics of septic equine synovial fluid *
Yellow to orange
turbid , opaque
low viscosity
>4g/dl protein
>30,000 (x10^6) nucleated cell count
>90% neutrophils (degenerative or non-degenerate)
You have a 10yo QH mare with a sustained laceration to the left hind pastern from wire fence
upon arthrocentesis of coffin joint you get
TNCC: 18,200/uL
85% neutrophils
TP: 3.8 g/dL
Is it infected?
Yes
How do you treat septic arthritis in horses **
1) LAVAGE
-Synovial irrigation +/- arthroscopy
2) Antimicrobials
-Intra-synovial
-Intra-osseous
-IV perfusions
-Systemic
3) Anti-inflammatory
4) Limb support- bandaging, splinting, casting
In horses, why are systemic antimicrobials controversial w septic arthritis
they might not get good penetration into the joint
acute infection of the dermis and SQ tissues with associated inflammation
cellulitis
What are the clinical signs of cellulitis in horses
-Severe generalized swelling
-Heat
-Pain on palpation
-Lameness (4-5/5)
-Fever
-Extension of wounds/pastern dermatitis
T/F: you see fever with cellulitis in horses
True
How do you diagnose cellulitis in horses
1) Clinical signs
2) Ultrasound- thick SQ space or gas if anaerobe
3) Radiographs (to rule out fracture)
4) FNA or biopsy (not typically done)
5) Aerobic / anaerobic culture of drainage of SQ pockets
(Staphylococcus and Streptococcus spp are most common)
What bacteria typically cause cellulitis in horses
(Staphylococcus and Streptococcus spp are most common)
if involves wound, external environment brings gram - bacteria within
How do you treat cellulitis in horses
1) Systemic antibiotics (Enrofloxacin)
2) Regional limb perfusion
3) Anti-inflammatory medications
4) Analgesics
5) Bandaging
6) Hydrotherapy (+/- compression): game ready system
What systemic antbiotic would you want to use to treat cellulitis in horses
Enrofloxacin
rapidly progressing necrosis of muscle due to bacterial infection from penetrating wounds, IM injection, hematogenous spread
Bacterial myositis
What typically causes bacterial myositis in horses
-penetrating wounds
-IM injection
-hematogenous spread
What typical organisms cause bacterial myositis
Clostridium spp (anaerobic)
Streptococcal spp
Staphylococcal spp
Corynebacterium pseudotuberculosis
Salmonella
IM injections of ________ can cause bacterial myositis in horses
Banamine
In horses, banamine causes __________ when given IM
Bacterial myositis
rapidly progressing necrosis of muscle due to bacterial infection from penetrating wounds, IM injection, hematogenous spread
How do you diagnose bacterial myositis in horses
Swollen horse
Ultrasound
Fluid aspirate (gram stain)
-Dont want to wait to get a culture back
How do you treat bacterial myositis in horses
-Systemic antibiotics (ensure anaerobic coverage
-Anti-inflammatories/ pain management
-Surgical fenestration and debridement (wound management, maggots, hyperbaric oxygen therapy)
-Supportive care
What is the purpose of exxternal coaptation (bandaging)
prevent further wound contamination
prevent edema formation
provide support to the limb
types of bandaging (external coaptation)
robert jones- double /triple limb size
foot- enclose entire foot
distal limb - heel to just below carpus/tarsus
fill limb (stack)- heel to just below elbow/stifle
What is the purpose of Robert Jone’s bandage in horses
Provide support
Limit joint mobility
Stop hemorrhage
Enable compression
What supplies do you need for a Robert Jones bandage
Roll cotton / combine
Gauze
Vetwrap
Elastikon
What is the purpose of bandaging a horse’s foot
Sole abscesses
Wounds
Protect bottom of foot
How should you bandage a horse’s distal and full limb?
apply bandage tightly
ensure even distribution to avoid pressure sores/ bowed tendons
wrap in the same direction
types of splints in horses
1) PVC
2) Kimsey (velcro)
3) Cast material (orthoglass)
-Planar support (lateral/medial or cranial/caudal)
4) Casts- circumferential support, most stable
What is the difference between a splint and cast
cast you get circumferential support while splint you only get a couple of planes
Types of casts in equine
1) full limb cast
2) Distal limb- below carpus and tarsus
3) Sleeve/tube cast - immobilized carpus but not the carpus and foot
4) Foot cast
How often should you monitor equine casts *
twice a day at least
What should you monitor in an equine casts *
1) Heat
2) Drainage (strike through)
3) Lameness
4) Fly accumulation
5) Unwilling to stand on it - pick up contralateral (uncasted limb)
How often should you change an adult horse’s cast *
every 3-4 weeks
How often should you change a foal’s cast *
every 1-2 weeks
they are growing frequently
How often should you change a horse’s splint *
usually with bandage changes or every 1-2 weeks
What are common sites for cast sores in horses *
-Proximal dorsal MC3/MT3
-Palmar / plantar fetlock
-Heel bulbs
How do you control a horse’s anxiety with fracture stabilization
sedate but do not oversedate or they may forget they have a broken leg and step on it
In horse’s with fractures, what should you give to provide analgesia
phenylbutazone
NSAIDs alone will not cause over loading on a fractured limb
What should you do for sedating a horse with a fracture
Short acting sedation with xylazine / butorphanol
Don not oversedate- stabilizing the limb will reduce anxiety
avoid acepromazine with severe blood loss (hypotension)
If you have a horse with an open fracture, what should you use
broad spectrum antibiotics
If you have a horse with severe blood loss, what should you avoid when doing sedation
acepromazine
What are the goals of fracture immobilization in horses *
1) Prevent further soft tissue damage
2) Minimize further none damage / fracture displacement
3) Stabilize limb to improve comfort and reduce anxiety
4) Determine best coaptation strategy (based on region)
What do you do for fracture below the fetlock (hoof to distal MC3)?
bandage and apply DORSAL splint with leg non-weight bearing
Kimzey is useful
Aligns dorsal cortices of cannon bone/ phalanges
What do you do for equine fractures of the distal metacarpus to distal radius
ex: MC3, carpal, distal radius
thick bandage and apply lateral AND caudal splint
function: prevents medial to lateral and dorsal to palmar instability, not good collateral support here
What do you do for distal radius to elbow fractures in horse
ex: radius fractures
1) thick bandage
AND
2) apply caudal splint (ground to elbow)
AND
3) lateral splint (above shoulder)
function: prevents limb abduction and further injury in the medial aspect
In horses with radius fractures, why do you need to apply a lateral splint that goes above the shoulder in additon to a caudal splint?
prevents limb abduction and further injury in the medial aspect
What do you do for a horse with a fracture of the elbow to scapula
ex: humerus and scapula fractures
no coaptation is necessary
surrounding muscles provide support
splints cannot stabilize joint above
splinting adds weight and can create a fulcrum at fracture making it worse
You shouldnt do coaptation in equine fractures that are above the elbow except if theres an
olencranon fracture- disrupt triceps apparatus causing dropped elbow inability to extend carpus
What should you do for horses with an olecranon fracture
apply full limb bandage and place CAUDAL splint
function: prevents limb abduction and further injury to the medial aspect
What do olecranon fractures lead to in horses
disrupt triceps apparatus causing dropped elbow inability to extend carpus
What should you do for a horse with a fracture between the hoof and distal MT3?
ex: P1, P2, distal Mt3 fx
bandage and apply PLANTAR splint with leg non-weight bearing
function: aligns plantar cortices of cannon bone/phalanges
How does tx of hoof to MC3 fractures from hoof to MT3 fractures
Front limb: apply dorsal splint
Hindleg: apply plantar splint
What should you do for horses with a fracture of the tibia, mid tarsus
thick bandage and apply extended lateral splint to the hip
limb angle and reciprocal apparatus make splinitng challenging
function: prevents limb abduction and further injury to the medial aspect
What should you do for a horse with a fracture from the stifle to the hip
ex: femur fractures
No coaptation is necessary
-surrouding muscles provude support
-splint cannot stabilize joint above
-splinting adds weight and can create a fulcrum at fracture
distal hindlimb musculature attachments enable more stbaility than upper forelimb fractures
How do you transport horses with fractures
minimize how far the horse has to walk
bring trailer to horse
forelimb fracture- haul facing backwards
hindlimb fracture- haul facing forward
How should you haul a horse with forelimb fx
haul facing backwards
How should you haul a horse with a hindlimb fracture
haul facing forward
What factors have a better prognosis for equine fracture repair **
1) young age (foals)
2) Small patient
3) Closed fracture
4) Simple / minimally displaced fracture
5) Early intervention
6) Non-articular
7) Good mental attitude
What fractors have a worse prognosis for equine fracture repair? *
1) Older horse
2) Large patient
3) Open fracture
4) Comminuted fracture
5) Severe soft tissue disruption
6) Articular
8) Poor mental attitude
What equine fractures are repairable
-Olecranon
-Phalangeal
-Metacarpal/Metatarsal
-Carpal/tarsal
-Radius (closed minimally displaced)
-Humerus, radius, femur, and tibia in foals
What equine fractures are very difficult / non-repairable
-severely comminuted
-most radius fractures in adults
-humerus, femur and tibia in adults
-open radius and MC3/MT3 fractures
equine fractures conservative management
-Non-displaced fractures
-Tie line to prevent laying down
-provide extra support with a cast or transfixation pin cast
luxation requires
disruption of several of structures
-Collateral ligaments
-Muscles/tendons
-Osseous articulations
-Joint capsule
-Joint fluid (cohesion/adhesion)
additional fractures may occur during trauma
How do you treat joint luxation in horses
-Splints
-Cast
-Internal fixation
-Arthrodesis
outcome: depends on joint involved/ amount of soft tissue trauma and stability of repair
complications: re-luxation, lameness, and osteoarthritis
If just the fetlock is dropped down, what tendon is likely lacerated *
Just the superficial digital flexor tendon
If the fetlock is dropped down and the patient’s toe flips up, what tendon(s) are likely lacerated *
Both the superficial and deep digital flexor tendons
If the fetlock, P1, P2, and P3 are all on the ground, what tendons are likely lacerated? *
Superficial and Deep Digital flexor tendons and suspensory ligament
How do you treat flexor tendon lacerations in horses
Suturing is rarely feasible
Tenoscopy if in digital flexor tendon or tarsal sheath
casting 6-8 weeks at least (cast in slight flexion)
shoe support- elevate heels or caudal extension
What is the outcome with flexor tendon lacerations?
50% return to work
depends on structures involved- synovial fluid reduces ability of tendon to heal
-adhesion formation in tendon sheaths
occur due to dorsal lacerations
unable to extend the fetlock
tx: bandage, splint and/or cast to prevent knuckling over
and stall rest 6-8 weeks
outcome: 75% return to full return, Stringhault (hindlimbs)
Extensor tendon lacerations
Are flexor tendon or extensor tendon lacerations better prognosis in horses
Extensor tendon lacerations
What should you consider about the other non-lame foot when treating a lame foot
laminitis can occur- once injured limb is stable, provide mechanical support to the contralateral limb
can have successful repair but lose a horse to laminitis, even 2-6 weeks post injur
How do you support the limb to prevent laminitis
encourage early weight bearing on injured limb (if stable)
pain management
caudal epidural (hindlimbs)
encourage horse to lay down on heavy bedding
mechanical support- soft ride boot and Nanric Ultimate (releases tension on laminae and pulling from DDFT)
What is a risk of any severe lameness
support limb laminitis
most causes of lameness in the equine forelimb is in the
Fetlock region and distal (80% of lameness)
When doing an equine orthopedic exam, what should you assess *
Abnormal?
-Swelling?
-Effusion?
-Limb alignment?
What anatomic structures are nearby
-Synovial structures
-nerves
-Blood supply
-Tendons/ligaments
Once you notice the lame leg, how do you localize the source in a horse
Nerve/ synovial blocks
exceptions: severe lameness and instability (e.g fractures)
suggestive finidngs:
severe swelling
pain on palpation
abnormal anatomy
findings on diagnostic imaging
When do you not want to use nerve/ synovial blocks to localize the source of the lameness
severe lameness and instability (e.g fractures)
Ringbone is ____ *
osteoarthritis of the interphalangeal joints
Low= dDIP or coffin
High= PIP or pastern joint
How do you treat ringbone?
Both low and high are challenging to manage medically
-Intra-articular injections (corticosteroids, hyaluronan)
-NSAIDs
-Extracorporeal shockwave (transient)
Arthrodesis: Surgical joint fusion
prognosis-
PIPJ- athletic use (90% hindlimbs) and (70% forelimb)
DIPJ- salvage
What surgery is used to treat severe ringbone
Arthrodesis: surgical joint fuson making P1 and P2 a single bone
prognosis-
PIPJ- athletic use (90% hindlimbs) and (70% forelimb)
DIPJ- salvage
How do you distinguish swelling of the fetlock vs tendon sheath
find the suspensory branch and see where it separates.
if dorsal = fetlock
if palmar = digital flexor tendon sheath
How do you treat fetlock joint - synovitis and osteoarthritis
Intra-articular medications
when medical therapy fails do surgical
-arthroscopy if underlying structural damage
-Arthrodesis: salvage/breeding
Dorsal proximal P1 fragments lead to
fetlock hyperextension
Dorsal proximal P1 fragments are common in
racehorses
How do you diagnose osteochondral dorsal proximal P1 fragments
variable lameness
joint effusion
intra-articular or low 4 point block
radiographs- can be small fragments, use oblique projections
How do you treat fetlock joint osteochondral fragments
-Surgical (arthroscopic) removal is preferred
-Conservative management has been reports (Risk of progressive OA, no clinical effusion or lameness)
prognosis - generally good, unless concurrent injury to articular cartilage
How do you diagnose subchondral bone cysts in horses
+/- effusion of fetlock
Intra-articular or low 4point perineural anesthesia
radiographs
How do you treat subchondral bone cysts in horses
1) intra-cystic or intra-articular corticosteroids (not good for older)
2) Surgically (preferred)
-Arthroscopic debridement
-Lagscrew across the cyst
prognosis: variable (good to fair) based on cartilage damage/joint degeneration
What are the 3 carpal joints in the horse *
Radiocarpal
Middle Carpal
Carpometacarpal joint
What equine carpal joints always communicate
carpometacarpal joint and middle carpal joint
T/F: the carpometacarpal joint and middle carpal joint always communicate in the horse
True
T/F: the radiocarapl and middle carpal joint always communicate in the horse
False
In horses with carpal osteochondral fragments, as dorsal fragments or palmar fragments more common
dorsal fragments
What carpal joints are most commonly affected by osteochondral fragments in horses
Radiocarpal and middle carpal joints
-hyperextension injuries
-high motion joints, common in racehorses
How do you treat carpal joint osteochondral fragments in horses
Arthroscopic removal
good prognosis if not a lot of articular cartilage is damaged
What gait abnormality do horses with elbow OA and subchondral bone cysts have
decreased cranial stride/lameness
How do you treat horses with elbow subchondral bone cysts
surgery: peri-articular curettage/drilling screw placement, biologic augmentation
elbow is much more difficult, not good fusion option *
What gait abnormality do horses with shoulder OA
decreased cranial phase of stride- not pathognomonic for shoulder
How do you diagnose shoulder OA in horses
1) Intra-articular anesthesia
2) Radiographs +/- contrast
3) Nuclear scintigraphy
How do you treat shoulder OA in horses
intra-articular treatment
arthroscopy
arthrodesis - miniature horses
prognosis is variable- shoulder OA is difficult to manage
What breed on horses can you do shoulder arthrodesis for shoulder OA
miniature horses - good prognosis, a lil of a gait abnormality
If fractures involve the articular surface, what is likely to occur
-More likely to lead to OA
-More challenging to accurately reconstruct
In the horse what phalangeal fractues are most common
P2>P1>P3
How do you treat phalangeal fractures in horses
Internal fixation
external fixator (transfixation pin casts)
shoeing support (P3 only)
transfixation pin cast
used for comminuted P1 fractures
always for transfer of weight out through pins and down the cast material
How do you treat proximal phalangeal fractures in horses
Incomplete- lag screw fixation (possibly conservative management)
Complete- lag screw fixation
Comminuted- transfixation-pin cast +/- scres
prognosis: variable, depends on reconstruction of articular surfaces
simple and complete/ non displaced is good
What does the prognosis of proximal sesamoid bone fractures in horses depend on
check the suspensory branches- attaches along abaxial margin
damge to distal sesamoidean ligaments
How do you treat proximal sesamoid bone fractures in horses
if small and on margin- arthroscopic removal
if large, internal fixation
Dorsal metacarpal disease in horses
Shin splints (Bucked shins)
common in young racehorses (2&3 year olds)
variable lameness
painful on palpation
thickening over the dorsal aspect of MC3
leads to stress fractures
How do you diagnose Dorsal metacarpal disease in horses
physical examination- painful when palpating dorsal MC
Radiographs + Nuclear scintigraphy
How do you treat Dorsal metacarpal disease in horses
modify training
extracorporeal shockwave
drill (osteostixis), place screw
abnormal abaxial proliferation along the splint bones in horses
leads to variable lameness and palpable pain (can go on suspensory ligament)
might just be cosmetic problem
Splint bone exostosis
Why might splint bone exostosis be painful
abnormal abaxial proliferation along the splint bones in horses
leads to variable lameness and palpable pain (can go on suspensory ligament)
How might you diagnose splint bone exostosis
radiographs
Ultrasound- check suspensory ligament
How do you treat splint bone exostosis
Usually conservative
Anti-inflammatories, rest, icing, bandaging
Surgical debulking if impinging on suspensory ligament
What is the prognosis with splint bone exostosis
good
Are medial or lateral splint bone fractures more common
lateral
Are distal or proximal splint bone fractures most common
distal
How do you diagnose splint bone fractures in horses
Radiographs
Ultrasound- check suspensory ligament- most common concurrent injury
What soft tissue structure is often involved in splint bone fractures
suspensory ligament
How do you treat splint bone fractures *
Primarily Conservative- rest, bandaging, anti-inflammatories
only surgical if:
1) causing lameness
2) If draining wound, the bone is a nidus for infection- only remove fractured portion (up to 2/3 removed safely)
3) Consider weight bearing or instability
Do internal fixation- proximal fractures/stabilize proximal articualr surface
For splint bone fractures, you should primarily do conservative management but when should you consider surgical
1) causing lameness
2) If draining wound, the bone is a nidus for infection- only remove fractured portion (up to 2/3 removed safely)
3) Consider weight bearing or instability
Do internal fixation- proximal fractures/stabilize proximal articular surface
Carpal slab fractures
commonly racehorses
3rd carpal bone is most affected (frontal and sagittal plane)
tx: internal fixation and arthroscopic guided
prognosis: fair to good
Olecranon fractures on horses typically occur due to ____ *
kick injury
What do you see with olecranon fractures in horses *
dropped elbow from disrupted triceps apparatus
What are your 4 differentials for a horse with a dropped elbow *
1) Olecranon fracture
2) Radial nerve paralysis
3) Triceps myopathy
4) Humerus fracture
What is the prognosis of horses with olecranon fractures *
good to fair
but can change with open vs closed and elbow osteoarthritis
How do you treat olecranon fractures in horses *
internal fixation- tension band plating
-some can be treated conservatively (non-articular and not displaced)
How do you identify palmar pastern soft tissue injuries
Ultrasound
MRI
What is windpuffs
digital flexor tendon sheath tenosynovitis
-effusion there
When is digital flexor tendon sheath tenosynovitis clinically significant in horses
if lameness is present with asymmetrical effusion
fatigue, accumulation of repetitive microtrauma to the metacarpal tendon
commonly SDFT ?DDFT
Flexor tendoinits
is SDF tendonitis more common in the forelimbs or hindlimbs
forelimbs
Bowed tendon
SDF tendonitis
How do you diagnose flexor tendonitis
mild to moderate lameness (1-3/5)
palpably thickened tendon that is painful on palpation
rounded profile
diagnostic: ultrasound or MRI
what causes suspensory desmitis
repetitive strain or acute overstain injury (degenerative)
Where can suspensory desmitis occur
anywhere along the suspensory ligament
1) Proximal at origin (proximal metacarpus)
2) Midbody
3) Branches (insert at abaxial sesamoid ligament)
What block is used to diagnose suspensory desmitis
Perineural block
-Low 4 point -branches
-Lateral palmar (wheat) proximal
-Midbody
How do you diagnose suspensory desmitis
1) Perineural block
-Low 4 point -branches
-Lateral palmar (wheat) proximal
-Midbody
2) Ultrasound
3) Radiographs
4) MRI
How do you treat palmar soft tissue injury in horses
Acute: cryotherapy, bandaging, anti-inflammatories
Ultrasound guided intra-or peri-lesional injection of platelet rich plasma or mesenchymal stem cells
Shockwave
Rest and Rehabilitation (controlled exercise for 6+ months)
Damage to the suprascapular nerve in horses leading to atrophy of the supra and infraspinatus muscles
shoulder sweeny
In shoulder sweeny, what muscles are atrophies
supra and infraspinatus muscles
What nerve is damaged with shoulder sweeny
suprascapular nerve
How do you treat Shoulder sweeney
rest
surgery to decompress the suprascapular nerve
What is the prognosis with shoulder sweeney
generally pretty good but it varies depending causes of damaged nerve (ie underlying fractures,etc) and chronicity
may take >1 year to heal
70% of equine hindlimb lameness is localized to the _______*
hock region or above
Where is most of the prevalence of equine forelimb conditions lameness *
most are below the fetlock
With hindlimb lameness in horses, what can this cause *
lower back problems
hindlimb lameness is associated with back pain
Is OCD more common in the forelimbs or hindlimbs in hroses
hindlimbs
Is prognosis with high ringbone and P2 fractures better in the hindlimb or forelimb when doing surgical arthrodesis
hindlimb > forelimb (
Suspensory branch desmitits
Degenerative (DSLD)
bilateral condition
hindlimb is most commonly affected
Predisposed breeds (Paso Fino and Peruvian Paso)
Horses with long pastern may be predisposed
difficult to treat if degenerative
traumatic desmitis is a better prognosis
entire suspensory
Suspensory branch desmitits is commonly (unilateral/bilateral) and mostly affects (forelimbs/hindlimbs)
bilateral hindlimbs
Proximal suspensory injury in the hind limb is most common in ____-*
jumping dressage and western performance horses
What are the clinical signs of Proximal suspensory injury of the hindlimb *
grade 2-4/5 lameness
pain on palpation origin (plantar cannon and axial aspect of both cannon bones)
“compartment syndrome”
How do you diagnose Proximal suspensory injury
assess the bone
deep branch of the lateral plantar nerve block
Ultrasound
MRI
What block do you use to diagnose proximal suspensory injury
deep branch of the lateral plantar nerve block
How do you treat proximal suspensory ligament injury *
Medical (forelimb + hindlimb)
-Shockwave (better at ligament/bone interface)
-Biologics (PRP, MSC)
-Rest/ Rehab
Surgical (hindlimb)
-neurectomy
-fasciotomy
Surgical techniques such as neurectomy and fasciotomy are only useful in proximal suspensory injuries that are
hindlimb
How many joints are in the equine tarsus
1) Tarsocrural joint
2) Tarsocalcaneal joint
3) Proximal intertarsal joint
4) Distal intertarsal joint
5) Tarsometatarsal joint
What joints in the equine tarsus communicate
Tarsocrural and proximal intertarsal only communicate
Proximal and distal intertarsal sometimes communicate (least likely)
Distal intertarsal and tarsometatarsal only sometimes do
In the horse, the tarsocrural joint always communicates with the _______ *
proximal intertarsal joint
Sometimes, the distal intertarsal might comminucate with the
1) Proximal intertarsal joint
2) Tarsometatarsal joint
What joint of the equine tarsus has the largest joint pouch
tarsocrural joint - has dorsal and plantar components to it
easy for you to see effusion there
What is the only joint in the equine tarsus that sustains significant swelling from synvoial effusion
Tarsocrural joint
What might cause synovial effusion of the equine tarsus
1) Tarsocrural joint (only joint in the tarsus to see swelling)
2) Tarsal sheath
3) Calcaneal bursa
What does Bog spavin mean?
There is tarsocrural joint effusion
What causes bog spavin
idiopathic
OCD (esp young horses)
trauma
Synovitis/capsulitis
You see swelling of the tarsus in a horse, you want to evaluate if there is tarsocrural joint effusion. What do you do to confirm
Confirm if there is lameness with this
1) Radiographs for a cause,
2) Ultrasound
3) Arthrocentesis
4) CT/MRI
5) Arthroscopy
What are the most common locations to see OCD lesions in the tarsus of a horse ***
1) Distal Intermediate Ridge of the Tibia (DIRT)
2) Lateral trochlear ridge of the talus
3) Medial malleolus
Most common OCD sites of the equine tarsus ***
1) _________ Intermediate Ridge of the Tibia
2) ________ trochlear ridge of the talus
3) _________ malleolus
1) Distal Intermediate Ridge of the Tibia (DIRT)
2) Lateral trochlear ridge of the talus
3) Medial malleolus
How do you treat OCD lesions in the equine tarsus *
Arthroscopic debridement
prognosis is good
What does bone spavin mean *
there is distal tarsal joint osteoarthritis
What joints are commonly involved with distal tarsal joint osteoarthritis in horses *
1) Tarsometatarsal (TMT)
2) Distal intertarsal (DIT)
What causes distal tarsal joint osteoarthritis in horses *
-repetitive trauma
-poor confirmation
-incomplete ossification of cuboidal (tarsal) bones
-usually mature horses (juvenile OA can occur tho)
distal tarsal joint osteoarthritis in horses *
“Bone spavin”
Commonly TMT and DIT joints
Usually mature horses (juvenile OA does occur)
Causes: repetitive trauma, poor conformation, incomplete ossification of cuboidal (tarsal) bones
If a horse is having their hock injected for OA, what likely joints is it ? *
Tarsometatarsal and distal intertarsal joints as those are most commonly affected by tarsal OA
What are the clinical signs of distal tarsal joint OA in horses *
-mild to moderate lameness
-positive spavin test (full limb flexion)
-Positive Churchill test
-boxy appearance to distal tarsus
Churchill test
a test used to identify distal tarsal joint OA
pressure of dorsal medial tarsus (where horses are more likely to get osteophytes)
How do you diagnose distal tarsal joint OA in horses
1) Regional anesthesia- TMT/DIT joint block
Peroneal-tibial perineural block
2) Radiographs
-Osteophytes
-Subchondral lysis
-Subchondral sclerosis
-Joint space narrowing
3) Nuclear scintigraphy
How do you treat distal tarsal joint OA in horses
-IA corticosteroids +/- HA
-Systemic PSGAG or HA
-Oral joint supplements
-Shockwave
-Facilitated ankylosis (intra-articular drilling, laser facilitated, ethyl alcholol) to destroy articular cartilage and allow fusing
What are common sites for fractures of the equine tarsus
-Malleolus fractures
-3rd and central tarsal slab
-calcaneous fractures
How many patellar ligaments do horses have
3- medial, middle, and lateral
Structures in the equine stifle
-Patellar ligaments (Med, Middle, Lat)
-Collateral ligaments (med and lat) -femorotibial ligaments
-Menisci (med and lat)
-Cruciate ligaments (cr + cd)
-Meniscotibial (4) and meniscofemoral (1) ligaments
-Articular cartilage
-Bone
-3 joint compartments
How many stifle compartments are there in the equine stifle
3
1) Femoropatellar joint
2) Medial femorotibial joint
3) lateral femorotibial joint
What two joints in the equine stifle always communicate
Femoropatellar joint and medial femorotibial joint
T/F: the femoropatellar joint always communicates with the lateral femorotibial joint
False- Femoropatellar joint and medial femorotibial joint always ocmmunicate
What joints in the equine stifle might communicate
ALWAYS: Femoropatellar joint and medial femorotibial joint
SOMETIMES: lateral femorotibial and medial femorotibial joint
T/F: the femoropatellar joint always communicates with the medial femorotibial joint
True
How do you test the stifle in your physical exam?
-Palpation
-Flexion tests
upper limb “Stifle” flexion
full limb flexion
attemp to discrimate tarsus from stifle
What anatomic structure prevents complete isolation of tarsus and stifle flexion *
Reciprocal apparatus
1) SSDFT
2) Fibularis (peroneus) tertius
If you are able to flex the stifle and extend the hock then what equine structure in broken
likely broke the fibularis tertius (cranial portion of the reciprocal apparatus)
What is the most common site to see OCD lesions in the equine stifle *
Lateral trochlear ridge
How do you diagnose OCD of the equine stifle *
-Moderate to severe effusion
-Usually low grade lameness
-Radiography (typically lateral trochlear ridge) see cartilage that failed to ossifty and some fragments
How do you treat OCD of the stifle in horses *
-Surgical (arthroscopic) debridement
-Cartilage absorbable pin fixation
prognosis is generally good
Is stifle OCD lesions in horses typically associated with a low grade lameness or high grade lameness **
Low grade lameness
Where do you see subchondral cystic lesions in the stifle in horses
Medial femoral condyle
What causes horses to have subchondral cystic lesions in the stifle (typically medial femoral condyle)
Osteochondrosis or traumatic (wt bearing surface)
How do you treat subchondral cystic lesions in the stifle in horses
-Intralesional cyst injection- inflammatory lining (good for younger horses)
-Debridement of the cyst with biologic augmentation
-Screw across the cyst- biomechanical support
prognosis is good if not other concurrent damage to meniscus or cartilage
Stifle synovitis/capsulitis or OA in horses
secondary to repetitive trauma, osteochondrosis or soft tissue injury
-Medial FTJ is most commonly affected
-Signs: variable lameness, usually low to mid grade, joint effusion, positive to flexion (upper and full limbs)
How do you treat stifle synovitis/capsulitis or OA in horses
1) Conservative: intra-articular therapies (corticosteroids, HA, IRAP, stem cells)
2) Surgery-Arthroscopy to rule out other structural injuries
-large bore lavage
When considering stifle synovitis/capsulitis or OA in horses, you shoould rule out other soft tissue injuries like
Menisci and associated ligamentous attachments
Collateral ligaments
Cruciate ligaments
Patellar ligaments
What would you see with patella fractures in horses
-acute onset of moderate to severe lameness
-Femoropatellar joint effusion/swelling
-May hold leg in partial flexion
The patella is not weight bearing so why might these fractures be a problem
disruption of the quadriceps apparatus
How do you diagnose and tx patellar fractures in horses
Dx via radiographs
tx: arthroscopy -fragment removal or internal fixation if large
do conservative management
prognosis is good for small fragments
guarded for large/comminuted
When does upward fixation of the patella occur in horses
when the medial patellar ligament remains locked on the trochlear of the femur
-horse has a really stiff gait to resolve it, cannot flex the stifle
-common in young horses into training
Upward fixation of the patella is common in horses that
are young and going into training
What are the clinical signs of upward fixation of the patella in horses
Mild- transition from extension to flexion is delayed and result in a popping
Severe- stifle locks and limb cant be advanced cranially
How do you treat upward fixation of the patella in horses
1) Conservative- increased exercise and improve muscle development
NSAIDS
2) Surgical
a) medial patellar ligament fenestration AND improve muscle development
b) LAST RESORT: transection of the medial patellar ligament
dont like to do this because you get trochlear ridge damage
You should only do transection of the medial patellar ligament to fix upward fixation of the patella if
it is the last resort
cutting it can lead to trochlear ridge damage
What is thoroughpin in horses
tenosynovitis of the tarsal sheath
often considered a blemish unless associated with DDFT lesions or sepsis
What is curb in horses
swelling or thickening of the long plantar ligament
see swelling below the plantar hock
usually chronic with no associated lameness
Swelling or thickening of the long plantar ligament
CURB
see swelling below the hock on the plantar aspect
usually chornic with no assicated lameness
What is Stringhault in horses?
exaggerated flexion of the tarsus during cranial phase of the stride (extensor tendons) , get better with trotting
usually unilateral
sequella of MT3 laceration
link to peripheral neuropahty: sweet pea/flat weed intoxication (bilaterally affected)
What might cause a horse to have an exaggerated flexion of the tarsus during the cranial phase of the stride
Unilateral: Sequella to MT3 laceration (extensor tendons)
Bilateral: possible peripheral neuropathy (sweet pea/ flat weed intoxication) - Australia
Stringhalt in horses is usually (unilateral or bilateral)
Unilateral
How do you treat Stringhalt in horses
lateral digital extensor myotenectomy if damaged
may spontaneously resolve if not caused by a wound
What results in overextension of the tarsus in horses
rupture of fibularis tertius
What are the clinical signs of fibularis tertius rupture in horses
Stifle can flex while the tarsus is extended
horses can bear wieght but lower limb may appear limp
How do you treat fibularis tertius rupture in horses
Conservative management for 4-6 months rest
good prognosis as scar tissue will readhere
Fibrotic myopathy +/- ossifying in horses occurs due to
1) limited action of semitendinosus
2) secondary to muscle injury
form fibrous attachment
clinical signs: slapping down of the limb at the walk in the cranial to caudal direction
What are the clinical signs of fibrotic myopathy +/- ossifying duie to limited action of the semitendinosus or muscle injury in horses
slapping down of the limb at the walk in the cranial to caudal direction
slaps back like a rubberband
goes away when the horse is in a trot
How do you treat fibrotic myopathy +/- ossifying due to limited action of the semitendinosus
Conservative management and rehab exercises is very important for success
myotenotomy of semitendinosus
transection of fibrotic tissue
What could cause the horses hindleg to slapping down of the limb at the walk in the cranial to caudal direction
slaps back like a rubberband
myopathy +/- ossifying due to limited action of the semitendinosus
What are common sites of thoracolumbar back pain in horses
1) Sacroiliac
2) Lumbosacral
3) Thoracic/Lumbar vertebrae (articular facets)
4) Dorsal spinous processes
T/F: horses with primary back pain can have lameness
True
How do you diagnose back pain in horses
Muscular palpation (*)
Nuclear scinitigraphy (if you cant locate)
Ultrasound
Radiography
How do you treat back pain in horses
1) Sacroiliac/lumbar facet injection
2) Extracorporeal shockwave
3) Chiropractic manipulations/ Rehab exercises
4) Medical management (NSAIDS, methocarbomol, gabapentin)
5) Desmotomy of interspinous ligament of impinging dirsal spinous processes so horses dont have the spnous processes rubbing on each other
