Lecture 10: Common Disorders of the Equine Hind Limb

cervical spine OA

• caused by trauma, unnatural head carriage, OC

• diagnosed by stiff neck, ± lame or neurologic, radiographs

• treatment → inject facets with corticosteroid, acupuncture, mesotherapy

• prognosis is fair

what is this?

cervical spine OA

impinging dorsal spinous processes

• kissing spines

• caused by trauma, poor fitting saddle

• diagnosed by pain on palpation, reduced performance, radiographs

• treatment → check saddle fit, inject area with corticosteroids, surgical resection

• prognosis depends on severity

what is this?

impinging dorsal spinous processes aka kissing spines

general back muscle pain

• caused by underlying hind limb lameness, poor saddle fit, poor riding, trauma

• diagnosed by pain on palpation, reduced performance

• treatment → check saddle fit, inject area with corticosteroids, acupuncture, rest

• prognosis is good once address underlying cause

sacroiliac disease

• arthritis

• subluxation of SI joint = hunter’s bump

• caused by trauma, inappropriate use

• diagnosed by clinical signs, acute → lame, can feel crepitus by rectal palpation

• treatment is rest and inject SI joint with corticosteroids

• prognosis is good

what is this?

hunter’s bump from sacroiliac disease

what are the structures involved with causing hind limb lameness in the horse ranked from most common to least common?

hock → below hock → stifle → above stifle

metatarsal 2 and 4 (splint bones) fractures

• caused by kick injury

• diagnosed by radiographs, observing wound

• treatment → ostectomy (segmental vs complete)

• prognosis is excellent

what is this?

splint bone fracture

hock lameness gait characteristics

• drags toes

• fails to “track up” on lame leg

• lame leg adducts most

• rider feels difference in their connection

• reduced performance

joint palpation for hock lameness

• often none

• bone spavin → hard swelling

• bog spavin → effusion

diagnosis of hock lameness

• flexion tests

• blocks

• radiographs

• nuclear scintigraphy

• CT

what is the most common hind end lameness diagnosed in performance horses?

hock OA

what joints are affected by hock OA?

distal intertarsal and tarsometatarsal joints

hock OA

• caused by athletic use or genetics

• diagnosed by + upper limb flexion, blocks to distal hock joints, radiographs

• treatment → intra-articular corticosteroids, shoeing, facilitated ankyloses or arthrodesis

• prognosis is good

what joints are affected in this radiograph?

distal intertarsal and tarsometatarsal

tibiotarsal effusion (bog spavin)

• caused by OCD, synovitis, OA (rare), blood (hemoarthrosis), infection (septic arthritis)

• diagnosed by effusion in TT joint, radiographs, ultrasound, diagnostic arthroscopy

• treatment → drain joint and inject corticosteroids, arthroscopy

• prognosis is good

hock OC location from most to least common

• distal intermediate ridge of the tibia (DIRT)

• trochlear ridge (lateral > medial)

• medial malleolus

what view is this?

DLPMO

plantar ligament desmitis (curb)

• caused by strain on plantar aspect of hock, sickle hocked horse

• diagnosed by characteristic swelling, mild to moderate lameness, blocks, ultrasound

• treatment → usually just need rest

• prognosis is good, will always have a curb swelling

what breed is overrepresented for plantar ligament desmitis?

standardbreds

what is this?

plantar ligament desmitis

calcaneal bursitis (capped hock)

• caused by repeated trauma → stall kicker

• diagnosed by characteristic swelling, generally not lame

• treatment → drain and inject corticosteroids

• prognosis is excellent for function, poor for cosmesis

what is this?

calcaneal bursitis

septic calcaneal bursitis

• caused by wound over calcaneus (common area to be kicked)

• diagnosed by being very lame, pressurize bursa, contrast radiographs, ultrasound

• treatment → flush bursa, regional limb perfusion, may require opening bursa and resecting part of calcaneus

• prognosis is guarded (50/50)

what is this?

septic calcaneal bursitis

tarsal sheath tenosynovitis (thoroughpin)

• caused by wear and tear, straight hocks

• diagnosed by characteristic swelling, usually not lame

• treatment → usually none

• prognosis is excellent for athletic use, guarded for cosmesis

what is this?

tarsal sheath tenosynovitis

ruptured peroneus tertius

• caused by trauma, full limb hind limb casts

• diagnosed by ability to extend the hock with a flexed stifle, lameness and swelling, tarsus extends more than usual at the trot

• treatment → avulsions near stifle, stall rest

• prognosis is good, poor if it involves stifle joint

superficial digital flexor or gastrocnemius muscle/tendon rupture

• caused by trauma

• diagnosed by clinical signs, ultrasound

• treatment → long term splinting and rest

• prognosis is fair to poor, good if it heals

what is this?

superficial digital flexor or gastrocnemius muscle/tendon rupture

fibrotic myopathy

• fibrosis ± ossification of the semitendinosus muscle

• caused by trauma

• diagnosed by characteristic movement (most evident at walk), palpable hardening in semitendinosus mm

• treatment → semiten ± semimem tenotomy

• prognosis is fair for success of treatment

gait characteristics of stifle lameness

• jumps off lame leg in weight bearing phase → quicker, short step

• drags toe because leaves leg out behind

• increased lameness when limb is on outside of circle

stifle lameness

• clinical signs → joint effusion (femoropatellar pouch easily palpable), hind end muscle atrophy with chronic problem

• diagnosed by flexion test of upper limb and caudal extension, blocks, radiographs, ultrasound, arthroscopy, nuclear scintigraphy

stifle OC

• most common breeds are WB, TB, QH

• lesions → medial femoral cysts, trochlear ridge OCD

• diagnosed by effusion, lameness when starts training, radiographs

• treatments → surgery → wait until 1 yr

• prognosis depends on severity and success of surgery, leads to OA

what is this?

medial trochlear ridge OCD on stifle

what is this?

stifle cyst lesion from stifle OC

stifle OA

• caused by underlying OC, trauma, athletic use

• diagnosed by blocks to the stifle

• treatment → intra-articular corticosteroids

• prognosis is fair - high in motion, complicated joint

upward fixation of patella

• inability to release stay apparatus → patella does not disengage from the medial trochlea of femur

• caused by weak quadriceps, straight legs

• diagnosed by stifle being locked in extension (severe) or horse catches their stifle (mild)

• treatment → immediate = back horse up, exercise strengthen quadriceps, surgery = medial patellar ligament splitting or blistering, medial patellar ligament desmotomy