Equine MSK diseases 2 Flashcards
Farriery, back
What are the aims of improving equine foot balance?
- Promote even weight bearing
- Level foot fall
- Facilitate ease of movement
What are the 3 dimensions of equine foot balance?
- Mediolateral (long axis)
- Hoof pastern axis
- Foot shape
How can the long axis of the equine foot be assessed with regards to foot balance?
- Look for even amount of forelimb and foot either side of mid line
- Can place T square over limb to assess more accurately
What is the approximate ratio that the equine toe wall and heel should be at?
Toe wall: heel wall at 3:1
What are the main aims of shoeing a horse?
- Achieve balanced foot with a normal axis
- Or as protection from abrasive forces
- Or to provide additional grip
Outline the code of conduct for the working relationship between vet and farrier
- Attend cases at the same time where possible
- Dialogue between vet and farrier is essential
- Share knowledge
- No messages passed via the owner
- Discuss cases together and decide on approach together with owner
What are the different categories of equine shoe available?
- Remedial
- Therapeutic
- Surgical
- Special
Outline the function and properties of a straight bar shoe
- 360degree support
- Load/offload parts of the foot
- Heel support
- Increased ground surface
- Equal weight distribution
In what conditions would a straight bar shoe be appropriate?
- Sheared heels
- Hoof cracks
- Conditions of balance that cannot be corrected by trimming
Outline the functions and properties of an egg bar shoe
- 360degree support
- Load/offload
- SDFT support
- Fetlock joint support
- Moves centre of gravity of foot rearwards
- Can extend behind the heels of the foot
What is the key feature that needs to be ensured with the application of an egg bar shoe?
The end of the shoe must bisect the centre of the fetlock
In what conditions is an egg bar shoe indicated?
- Strained SDFT
- Navicular syndrome
- Caudal foot pain
- Can be used in the same way as a straight bar shoe
Outline the functions and properties of a heart bar shoe
- 360degree support
- Load/offload
- Frog support
- Allows front of foot to take some weight
- Can be aluminium, steel, plastic, leather, pads etc.
In what conditions is the use of a heart bar shoe indicated?
- Hoof cracks
- Frog pressure
- Frog support
- Laminitis
- Heel avulsions
What is the key feature that needs to be ensured with the application of a heart bar shoe?
The tip of the bar should be level with the widest part of the shoe
What is the function of a lateral extension shoe?
Provide lateral support to the limb
When is use of a lateral extension shoe indicated?
- Poor conformation
- Angular Limb Deformity
- Foals: bow-legged, carpal deviation, mediolateral deviation of limb
- To provide comfort in older horses
Outline the function of a graduated shoe
- Heel elevation
- Alters angle of the dorsal wall, HPA, DIP joint
In what conditions is use of a graduated shoe indicated?
- Poor conformation e.g. broken forward HPA
- DDFT strain/injury
- Alleviate stress in coffin joint
How does placement of a graduated shoe aid with DDFT strain/injury?
Slackens area, reduces strain on DDFT
What is the main risk associated with a graduated shoe?
Hoof capsule may run away with itself and become too long
What may cause a sole infection in horses?
Penetrating foreign bodies e.g. stones, nails, thorns
What clinical signs would be expected with a solar infection in the horse?
- Lameness
- Heat/pain in the foot
- Increased digital pulse
Outline your approach to diagnosing a suspected solar infection in the horse
- Foreign body may be visible
- If not, use hoof testers, even pressure all the way around moving from bulb to bulb
Outline the treatment for a solar infection in the horse
- Release pressure
- Drainage
- Poultice
- Antibiotics
- Hospital plate on top of straight bar shoe, remove daily and flush
- Foot pads if soles are weak
Outline the signs of white line infection in the horse
- Cracks/fissures of the hoof wall
- Separation of the hoof wall
- Crumbling horn
- Hollow wall
Outline the treatment of white line infection in the horse
- Debride area
- Remove loose wall
- Keep area clean using topical solutions, avoid turnout onto wet/muddy fields
- Glue can be used to fill gaps left by debridement, then rasped down to produce smooth wall
What is equine foot thrush?
Aerobic infection of the clefts of the frog
Describe the signs of foot thrush in the horse
- Foul odour
- Black discharge
- Exposed tissue
- Atrophy
- Lameness
What may cause foot thrush in the horse?
- Poor conditions
- Lack of foot trimming
Outline the treatment of equine foot thrush
- Remove the underlying cause
- Debride area
- Trim foot
- Keep area clean/dry
- Peroxide, antibacterial sprays
What is meant by solar bruising in the horse?
Rupture of capillary beds
What may cause solar bruising in the horse?
- Unshod feet
- Foot wearing out
- Stones
- Uneven ground
- Can be caused by shoe, if flattened sole drops through and contacts the ground i.e. becomes convex
Describe the signs of solar bruising in the horse
- Reddening of the sole
- Pain on hoof testers
- Lameness
Outline the treatment of solar bruising in the horse
- Apply seated shoe
- Pads (synthetic or leather)
- Sole packs
What may lead to hoof wall lesions in the horse?
- Uneven weight bearing
- Imbalance
- Direct trauma
- Poor quality horn
- Environmental factors
- Poor farriery
Outline the treatment of hoof wall lesions in horses
- Address foot balance
- Immobilise foot
- Support foot
- Use of bar shoes
- Foot trimming
- Filler to provide rigidity and stability to foot as well as preventing further cracking
What shoe would be most appropriate to use in a case of laminitis?
Heart bar shoe
What is meant by nail bind in horses?
Where the nail from a shoe is in contact with, but not penetrating, the sensitive structures of the foot leading to lameness
How many thoracic, lumbar and sacral vertebrae does a horse have?
- 18 thoracic
- 6 lumbar
- 5 sacral
What is the function of the longissimus dorsi muscle? Origin and insertion?
- Back movement and stabilisation
- From 6th and 7th cervical vertebrae to the ilium
What is the function of the gluteal muscles?
Extend hip, retract limb and support outward rotation
Outline the key signs of back pain in the horse
- Loss of performance
- Loss of suppleness/impulsion
- Stiffness/reluctance to bend/flex
- Cold backed to saddle/rider
- Changes in temperament
- Bucking/rearing
- Pain on palpation
- Difficult shoeing/urinating
Outline the assessment at rest where back pain is suspected in the horse
- Pain on palpation of back
- Muscle wastage/spasm, localised swelling
- Reduced movement (lateral bending, dorsal and ventral flexion, circling)
- Tail tone
- Saddle fitting
Outline the assessment at exercise where back pain is suspected in the horse
- Walk and trot in straight line
- Flexion tests to rule out bilateral HL lameness
- Lunging, circling, serpentine
- Backing
- Canter work on lunge
- Ridden exercise
- Look for signs of lameness
What diagnostic tools are used for diagnosis of back pain in horses?
- Regional infiltration of local anaesthesia
- Biochemistry
- radiography
- Scintigraphy
- Ultrasonography, themography
What condition causing back pain is regional infiltration of anaesthesia a useful diagnostic tool for?
Impingement of dorsal spinous processes (aka kissing spine)
What conditions causing back pain is biochemistry a useful diagnostic tool for?
Myopathies (look at CK and AST)
What conditions causing back pain are radiography and scintigraphy useful diagnostic tools for?
Bony lesions, fractures, kissing spine
Give examples of soft tissue conditions that may lead to back pain in the horse
- Muscle strains e.g. longissimus dorsi
- Ligament injuries e.g. supraspinous ligament
- Post exercise myopathy
Give examples of joint conditions that may cause back pain in the horse
- Sacroiliac joint disease
- Osteoarthritis
Give examples of bone conditions that may cause back pain in the horse
- Impingement of dorsal spinous processes (kissing spine)
- Fractures (usually associated with trauma, stress fractures in vertebrae of racehorses)
- Congenital or acquired vertebral deformities
- Osteomyelitis (rare)
Outline the prognosis for acute soft tissue injuries causing back pain in the horse
Generally respond well to local or systemic anti-inflammatories, rest and adjusting exercise regime
Outline the prognosis for joint conditions causing back pain in the horse
Poor prognosis for return to previous performance levels
Outline the prognosis for impingement of dorsal spinous processes
Can be treated by local or systemic anti-inflammatories, may not return to performance, surgical treatment is an option in some cases (refractory to conservative treatment, lesions located dorsally)
What structures make up the pelvis of the horse?
Os coxae (made up of ilium, ischium, pubis), sacrum and first 2/3 fused coccygeal vertebrae
What are the 5 articulations of the lumbosacral junction in the horse?
- Paired lumbosacral facet joint
- Paired inter-transverse joints
- Lumbosacral joint between 6th lumbar vertebra and first sacral vertebra, between which lies lumbosacral disc
What may a lack of symmetry in tubera coxae of the horse indicate?
Stress/traumatic fracture in one of these structures
What does a disparity in level of tubera sacrale indicate?
Displaced ilial wing - may also find crepitus of underlying bone
What may asymmetry of the gluteals indicate?
- If mild, low grade HL lameness
- If severe, may indicate pelvic injury e.g. complete pelvic fracture, acetabular or iliac shaft fracture
How can iliopsoas strain in the horse be diagnosed?
Palpation per rectum resulting in apparent pain response
How can subluxation and partial disc herniation of the lumbosacral joint in the horse be diagnosed?
Palpation per rectum to apply digital pressure to LS joint, resulting in pain response
How can osteoarthritic changes to the lumbosacral joint in the horse be diagnosed?
- No pain response on palpation
- Diagnose by ultrasonography
What may callus formation and/or soft tissue swelling felt in the pelvis during per rectum palpation indicate?
Complete fracture of acetabulum, iliac shaft, sacrum or pubis
What is the main indication for use of ultrasonography in a horse with pelvic pain?
To rule out pelvic fracture
What structures can be imaged using a linear transducer at the pelvis, transcutaneously?
- Dorsal sacral ligaments
- Tuber sacrale
- tuber coxae
- Tuber ischii
Outline the ultrasonographic examination of the dorsal sacral ligaments in the horse
- Linear probe, 8-13MHz
- evaluate transverse and longitudinal planes, assess shape, size, symmetry
- Echogenicity, typically homogenous
- Fibre pattern usually good
- Caudal extension of thoracolumbar fascia aka thin DSL can sit variably dorsal or medial to short DSLs
In which structures of the equine pelvis can fractures be detected in with variable sensitivity?
- Iliac wing
- Iliac shaft
- Acetabulum
- Ischium
Discuss the usefulness of ultrasonography in the detection of fractures of the iliac wing and shaft, acetabulum and ischium in the horse
- Usefulness depends on degree of callus formation and/or displacement of fracture edges
- Negative scan on TBs with clinical presentation of pelvic fracture should not reduce index of suspicion
- Subtle/early lesions easily missed
When should scintigraphy be carried out in horses in cases of suspected pelvic injury?
10-14 days after onset of signs to ensure significant amount of bone remodelling
Outline the typical appearance of lameness resulting from pelvic stress fractures in horses
- Similar to any other HL stress injury
- Plaiting, short strided HL gait
- Hx of variable lameness, may be sudden onset non-weight-bearing to low grade lameness when ridden that improves with rest
What are the 2 main differentials for a horse showing HL lameness, with gluteal and lumbar muscle spasms, and how can these conditions be differentiated?
- Bilateral iliac wing lesions
- Exertional rhabdomyolysis
- Rule out rhabdomyolysis on biochemistry
Outline the clinical signs of iliac shaft fractures in the horse
- Muscle wastage over affected area, occurs rapidly
- Severe lameness
- Variable asymmetry of tuber coxae
- Rocking of pelvis may demonstrate crepitus
Outline the clinical signs of acetabular fracture in the horse
- Muscle wastage over affected area, occurs rapidly
- Dramatic reduction in caudal phase of stride
- Hip region more prominent on clinical exam due to loss of muscle mass
- Soft tissue swelling
What would the following indicate in the horse?
Focal muscle loss to one/both sides of dorsal spine of sacrum, loss of bladder control, loss of anal sphincter reflex
- Sacral fracture
- Possibly EHV-1 (loss of bladder control)
What does the following finding on clinical examination indicate in the horse?
Palpation of fractured bone fragment in the sublumbar fossa, lameness
- Fracture of the tuber coxae
- Fragment displaced cranioventrally, may cause soft tissue trauma
What are the differentials for the following signs in a hose presented following a traumatic incident, and how can they be differentiated?
Obvious swelling of caudal thigh, loss of definition of ischial tuberosity, pain when firm digital pressure applied to area
- Fracture of ischial tuberosity
- Tears of semitendinosus/semimembranosis (differentiate by ultrasonography)
What will be detected on rectal palpation in the horse in a case of fractures through the acetabular physis?
Large soft tissue masses at 4 and 8 o’clock positions within the pelvis
What pelvic structures should be evaluated on per rectum ultrasonography in the horse?
- Sacroiliac joints
- Ventral sacroiliac ligaments
- Lumbosacral joints and disc
- Intertransverse joints
- Nerve roots and fossae
- Axial aspect of the coxofemoral joint
- Pubic symphysis
In a horse where pelvic fracture is suspected, but not identified on initial ultrasonography, how should the case be managed?
- Scintigraphy
- If scintigraphy not available, tie up in stable 10-14 days, repeat ultrasound
- If still nothing found, manage as a fracture until proven otherwise
Outline the clinical signs of sacroiliac and lumbosacral dysfunction in the horse
- Low grade lameness
- Poor performance
- Poor propulsion over fences
- Occasional reluctance to elevate HLs
- Shortened cranial swing phase, toe drag
Compare the clinical signs of acute sacroiliac ligament rupture, chronic SI ligament injury and lumbosacral joint injury
- Acute ligament: palpable discomfort surrounding tuber sacrale
- Chronic ligament: bucking after jumping or in groundwork
- Joint injury/luxation: ataxia
Outline the diagnosis of sacroiliac joint dysfunction
- Local anaesthesia using cranial, cranial midline and caudal approaches to the SIJ to localise pain to this region
- Ultrasonography and scintigraphy: modelling of joint margins (LS, SI, and ITJ), dystrophic mineralisation, hypoechoic/hyperechoic regions within disc tissue, protrusion of disc
In the equine pelvis, what is the ITJ?
Inter transverse joint - the joint formed between the last transverse process of the lumbar vertebrae (L6) and the sacrum
List the indications for radiography of the equine foot
- Lameness/pathology localised to foot/pastern
- Penetrating injuries
- Chronic infection/discharge
- Evaluation and monitoring or lamintis
- Assessment of foot balance
- Monitoring of treatments/corrections
- Pre-purchase/insurance examinations
List the radiographic views for a standard equine foot series
- Lateromedial
- Dorsopalmar
- 2x dorsoproximal, palmarodistal 60degree oblique views (pedal, navicular, or upright pedal)
- Palmaroproximal palmarodistal 45 degree oblique view
Describe the positioning for a lateromedial radiograph of a horse’s foot
- Fully weight bearing, standing square
- Centre on coronet band midway dorsopalmar
- Align beam parallel to heel bulbs
- Adjust film focal distance, collimate
- Marker placed dorsally on plate
Describe the positioning for a dorsopalmar radiograph of a horse’s foot
- Weightbearing
- Centre on coronet band, midway medial-lateral
- Adjust film focal distance, collimation, ensure beam horizontal
Describe the positioning for an upright peda/D60Pr-PaDi oblique projection of a horse’s foot
- D60Pr-PaDi oblique requires less people, may get image distortion
- Centre on coronet band
- Pack sulci
- Oblique: place toe at edge of plate, weight bearing, angle beam 60degrees to hoof wall
- Upright pedal: upright block, place toe on block, sole perpendicular to floor, plate behind, use horizontal beam perpendicular to plate
Describe the method for obtaining upright navicular/D60PrPaDi oblique projections of the equine foot
- Pack sulci
- Upright: use block, tip foot forward slightly so dorsal hoof wall ~85degrees from horizontal
- Tunnel/oblique: same as for P3 view, but centre 1-2cm above coronary band
- Tight collimation needed
Describe the method for obtaining a flexor navicular (Pa45PrPaDi) projection of the equine foot
- Foot on tunnel, place caudal on block
- Foot must be placed behind the foot not being radiogaphed
- Not always taken at 45degrees - take at steepest angle possible without hitting back of fetlock
- Centre between the bulbs
- Collimate, FF distance, angle sorted before taking radiograph to ensure minimal time spent under horse
What aspects are highlighted in the equine limb in a DLPMO view?
- Dorsomedial
- Palmarolateral
What aspects are highlighted in the equine limb in a DMPLO view?
- Dorsolateral
- Palmaromedial
Which horses are predisposed to axial skeletal disoders?
Adult athletes esp/ show jumpers and eventers
Which horses are predisposed to axial soft tissue injuries?
- Heavy framed
- Long backed TBs
Which breeds of horse are predisposed to vertebral injuries e.g. overriding spinous processes?
- Standardbreds, quarterhorses, other short backed breeds
- Warmbloods
- Racing TBs
Which breed of horse is prediposed to congenital spinal disorders?
Arabs
Give examples of congenital spinal disorders found in horses
- Sacralisation of the last lumbar vertebra
- Hemivertebrae (wedge shaped vertebral bodies causing spinal deformities
- Block vertebrae (fusion of several vertebral bodies)
What is roach back in horses and when does it commonly occur?
- Acquired kyphosis
- Younger Tbs in association with flexural limb deformities
Which horses are predisposed to marked lordosis/sway back?
Aged animals, frequently brood mares
