Equine Flash Notes - Lower Leg Lameness Flashcards
what are some other common names for dorsal metacarpal disease in horses?
bucked shins, shin splints,
what is the number one cause of lameness in 2-year-old race horses in their first training season?
bucked shins - dorsal metacarpal disease
too much too soon
what are the lesions seen with dorsal metacarpal disease?
periostitis & subperiosteal hematomas on dorsal metacarpal 3 - microfractures seen usually on dorsomedial aspect 2/3 of the way down the cannon bone
what are the causes of bucked shins?
concussion when the bone is not fully conditioned
stress on the dorsomedial surface which leads to an increase in thickness to compensate
is stress is faster than repairs, you get microfractures & subperiosteal hematoma formation
what is seen in horses with resolved cases of bucked shins?
new bone growth without pain
what is the classic case presentation of bucked shins?
acutely lame/pointing, short stride, increases with exercise, shuffling forelimb gait, & warm painful swelling on dorsomedial surface of MC3
what are the big differentials to consider for bucked shins?
fissure/saucer fractures of dorsal cannon
condylar fractures of MC3
soft tissue injury
what is the best view to diagnose bucked shins radiographically?
dorsomedial oblique - to highlight the dorsomedial surface
what is seen on rads that supports bucked shins?
acutely negative but with time will see subperiosteal lysis & subperiosteal callus formation
microfractures of the dorsomedial cortex of the bone
repeat rads in 7-10 days
how are bucked shins diagnosed?
clinical signs/age, palpation of dorsomedial aspect of MC3, acute pain/swelling, rads, & scintigraphy for bone scan
what treatment is used for all cases of bucked shins? what is used for mild cases? what about severe cases?
all cases - rest, controlled exercise program, & ice it if heat is felt
mild cases - 10-14 days of rest, controlled exercise program (hand walking, slow to moderate training), phenylbutazone, & topical DMSO painted on area SID/BID for 5-10 days to reduce inflammation
severe - convalescence for 1-3 months
what is the prognosis for bucked shins?
mild cases - good
severe cases - guarded, some may never get better, others take a year or more to become sound
how are bucked shins prevented?
deliberate controlled exercise programs!!!
90 days of galloping before speed work!!!
what are some predisposing factors to splints in horses?
excessive exercise when young, faulty conformation (bench knees where the medial splint bone is offset laterally & takes more weight or base narrow with the toe out which causes interference), improper nutrition (overweight)
what is the pathophysiology of splints in horses?
interosseous ligament can get torn due to stress
periosteal reaction occurs
medial splints due to stress & articulates with C2 & C3
what horses are often affected by splints?
young horses (~2 years old) in heavy training - affects the forelimbs, splint bones, on the medial side between MC2/MC3 where the interosseous ligament connects the splints to the cannon bone
what is the common acute presentation of splints? what about chronic?
acute - variable lameness that is most pronounced after work with swelling on the medial side of the metacarpus
chronic - blemish, more commonly seen!!! bony protuberance & lameness disappears
what are the sequela to splints in horses?
blind splint - swelling on the inside (axial) of the splint where you can’t see it
suspensory desmitis - encroachment on the suspensory ligament
how is acute splints diagnosed?
palpate pain/deep palpation & confirm with a local block or deep branch of the lateral palmar nerve
how is chronic splints diagnosed?
no pain palpated, bony swelling about 3 inches below the carpus
what is seen on radiology with chronic splints?
DLO view to look through interosseous space
osteolysis between MC2/MC3, osteoperostitis, dystrophic mineralization of the interosseous ligament
need to check in carpal joints are involved or if there is palmar extension to effect the suspensory ligament
what is the treatment for acute splints? what about chronic?
acute - complete rest for 7-10 days, bandaging to decrease swelling, cold hosing, NSAIDS, & no steroids!!!!!
chronic - if the bony prominence is impinging on the suspensory ligament or a cosmetic issue, can excise periosteum & bony growth with a pressure bandage 2 weeks after surgery & a light bandage another 2 weeks, & NSAIDS to reduce swelling and new bone formation but POSSIBLE RECURRENCE
what is the prognosis of splints?
good for athletes & cosmetic blemishes
guarded if it causes suspensory desmitis
what are some differentials for splints?
splint fractures
periostitis from interference
suspensory ligament strain
soft tissue trauma to metacarpus
what is the lay term for tendinitis?
bowed tendons
what is the number one site of tendon/ligament injury/strain in horses?
middle of the metacarpus
what are some predisposing factors to tendon/ligament injuries in horses?
racing (flat or steeple chase), fast, hard track»_space;> muddy track, inadequate training (highest incidence in 1st 3-4 racing starts), muscle fatigue, bad conformation with excessive pastern slop, & long toes
T/F: tendon/ligament strain/injury very commonly reoccurs in horses
true
how are tendon/ligament injuries in horses diagnosed?
history, clinical signs, & pain on palpation
ultrasound - necessary for treatment & prognosis
swelling/thickening of digital tendons
core lesion - anechoic area severe, black area
diffuse lesion
or localized to SDFT, DDFT, or suspensory ligament
T/F: there is no agreement on pathogenesis or treatment of tendon/ligament injuries in horses
true
what is the proposed pathophysiology of tendon/ligament injuries?
single episode or multiple episodes weakening tendon
tendons/ligaments elastic due to type 1 collagen bundles arranged in a longitudinal pattern with a crimped configuration - normal strain straightens out crimping when strain stops, crimping returns
abnormal strain tears apart fibers in a partial rupture - exudate/inflammation/edema/hemorrhage into ligament/tendon further separates fibers & release of hydrolytic enzymes further weaken tendon
collagen type 3 (granulation tissue) replaces type 1 cartilage which isn’t crimped or as strong, so further strain = bad
T/F: in horses with tendon/ligament injuries, they are always prone to further break down, 48% of SDFT rebow & 75% of them occur in the same limb
true
what is the prognosis of tendon/ligament injuries?
guarded - often will rebow
what treatment is used for tendon/ligament injuries?
reduce swelling - ice 48-72 hours & PBZ 7-14 days, tissue support by bandaging both lower limbs, & stall rest minimum 4 months
monitor healing with ultrasound
can do a proximal check ligament desmotomy for SDF tendinitis
what is the lay term for SDF tendinitis?
bowed tendon
what horses are predisposed to bowed tendons?
thoroughbreds, fore»_space; hind & L > R
standardbreds also occasional in hindlimbs
why is the location of SDF tendinitis important?
classification of the injury - middle 1/3 or MC/MT is SDFT, can see palmar/plantar fetlock, or can involve synovial sheath
what is the proposed pathophysiology of SDF tendinitis?
stretching/rupture of fiber bundles leading to edema/inflammation/hemorrhage which further disrupt fiber bundles
leads to ischemia/necrosis - healing leads to classic bowed tendon with inflammation/swelling/fibrosis with the cycle only broken by rest
what are some predisposing factors of SDF tendinitis?
smallest cross sectional area of SDF is mid cannon
poor blood supply to mid metacarpal region of tendon
uneven tight bandages may cause a bow
T/F: 10% of all racing injuries in horses are attributed to SDF tendinitis
true
what is the classic presentation of bowed tendons in horses?
acute pain mid-metacarpus, swelling, heat, lameness
at fetlock - tenosynovitis with swelling of the synovial sheath & notching of the annular ligament
chronic - firm, diffuse swelling on palmar/plantar aspect, may be sound at walk/trot, & lame after a workout
what is the only consistent finding of SDF tendonitis?
pain on palpation
how is SDF tendonitis diagnosed?
ultrasound - swelling/thickening of digital tendons, cross sectional area > 1.5cm for thoroughbreds indicates a bow but doesn’t hold for standardbreds
transverse ultrasound - look for disruption of parallel fibers
core lesion - anechoic area
diffuse lesion is worse
what is the downfall of treatment for SDF tendinitis?
none attains the goal of repair with maximum strength & adequate elasticity
what is the acute treatment used for SDF tendinitis?
emergency - stop the swelling, stop training to break the cycle, ice packs/cold hosing, tight padded pressure wraps, PBZ, & DMSO to reduce edema
what treatment is used for mild to moderate SDF tendintis?
conservative treatment - 6 month rehab program, stall rest 1 month, controlled exercise program for 3 months, & further 3-4 months light ridden exercise
regular monitoring with ultrasound - helps determine initiating/evaluating training (if anechoic area, no training)
what therapy is used for moderate SDF tendinitis?
SDF check ligament desmotomy, rest, & PBZ - some horses can train in 3 months
what treatment is recommended for severe or bilateral lesions of SDF tendintis?
proximal SDF check ligament desmotomy, 1 year rest, & controlled exercise program
what treatment is recommended for a discrete core lesion of SDF tendinitis?
tendon stab surgery & check desmotomy sooner rather than later because it improves tendon fiber organization - NOT FOR DIFFUSE LESION
what is the most important aspect of therapy that should be emphasized for horses with SDF tendinitis?
importance of 3-12 months rest for healing & strength - must use ultrasound to guide this
what is the prognosis for a horse with SDF tendinitis who has a tendon that remains large after aggressive treatment?
poor
better if the tendon becomes normal or near normal in size
why do standardbreds with a desmotomy for SDF tendinitis do better than thoroughbreds treated with the same therapy?
standardbreds have an even gait & symmetrical weight distribution
what horses are affected by suspensory desmitis?
standardbred on harnesses > thoroughbreds due to longer cranial phase of stride which is the support phase of the suspensory ligament (forelimbs > hindlimbs - standardbreds often affected in hindlimbs)
associated with periostitis, fx of splint bones, & sesamoiditis
what are the most common locations of suspensory desmitis in horses?
1 is both branches of suspensory ligament (medial > lateral) - end of splint bones may snap off when suspensory ligament snaps against it
body of the ligament secondary to splints or fracture of splints
what is the classic case presentation of acute suspensory desmitis?
usually presents for swelling with heat, pain, low grade lameness, & standing up right to take weight off of heels
what is the classic case presentation of chronic suspensory desmitis?
hard swelling, may be sound at walk/trot, lame after workout, & may sink at fetlock
what are the big sequelae associated with suspensory desmitis?
sesamoiditis - secondary involvement of proximal sesamoid bones due to tearing of insertion of suspensory ligament branches
often fractures of MTII
suspensory apparatus rupture if disruption of the branches of the suspensory ligament
what are some differentials to consider for suspensory desmitis in horses?
splints, DDFT strain, sesamoiditis, fx of splint bones, fetlock strain, rupture of suspensory apparatus, & proximal sesamoid fx
why is radiology necessary for diagnosing suspensory desmitis?
assess splint bones, sesamoiditis, mineralization within the tendon, avulsion of the proximal attachment, & sesamoidal fx with joint effusion usually present
how is suspensory desmitis diagnosed?
history, clinical signs, palpation (lift limb to loosen tendons), sensitivity to firm palpation of suspensory ligament
need to use u/a to define extent of damage & px
what is the treatment used for suspensory desmitis?
acute - emergency to stop swelling, icing limb, tight padded pressure wraps, PBZ for 10-14 days, extended rest for 6-10 months, monitor healing with ultrasound
what is the prognosis for suspensory desmitis?
better than flexor tendon tendonitis
good/guarded - branch desmitis
poor - complete rupture/salvage
what is stocking up/fat legs/humor in legs in horses?
common response to stall confinement after strenuous exercise - not a pathological condition that often just occurs in hind limbs (or all 4 in cutting horses)
what is the pathophysiology of fat legs in horses?
circulatory stasis - confinement causes pressure to build up in capillaries & fluid to leak out into tissues
what horses are predisposed to stocking up?
overweight horses, pregnant mares that don’t exercise, lame horses, shipping horses long distances, & excessive protein in diet
what are the common sequelae to fat legs in horses?
confinement due to injury - laminitis & navicular disease
what is the common presentation of stocking up in horses?
swelling of both hind limbs or all 4 limbs, tear drop shaped legs with indistinct borders, no lameness but may be stiff
how is stocking up in horses diagnosed?
swelling of back legs or all 4
cool, painless, pitting edema only below hock or carpus
swelling resolves with exercise
how is stocking up in horses treated?
rub leg with liniment vigorously before riding, warm up period (walking under saddle 15-30 minutes before riding)
swelling should go down with exercise
how is stocking up in horses prevented?
cool down period after exercise, brace/tightener after exercise, reduce concentrates in diet/increase roughage, support bandages if confinement anticipated (long trailer ride - make sure it is correctly applied to avoid tendon damage so save as last resort)
what is the prognosis for stocking up?
excellent
what is the most common salter harris fracture seen in horses?
type II - fx through the physis that breaks out through the metaphysis
what is the prognosis of physeal fractures in horses?
poor
better for <4.5 months than older because less weight
