26.5.1: Emergency fractures in the horse Flashcards
How do we classify fractures?
- Location: which bone involved, and where (metaphysis, diaphysis, epiphysis)
- Structures involved i.e. articular or non-articular
- Contamination i.e. open or closed. Horses generally do not do well with open fractures
- Extent of damage: complete/ incomplete, simple/ comminuted
- Size of fragment: chip vs slab vs shaft fracture
- Fracture configuration: transverse, oblique, spiral, avulsion, growth plate
- Displacement, fracture fragments, margins
Describe this fracture
- Simple transverse fracture of the accessory carpal bone
- Non articular and no evidence of external communication
- Moderate displacement with at least two fragments and irregular, poorly defined margins
- No joint effusion or swelling on the palmar aspect of the limb
- This is a chronic fracture; it is hard to stabilise and any screws (internal fixation) would probably fracture it further and maybe enter the joint
–> Recommend ultrasound to check carpal sheath and flexor structures, then conservative management. Guarded prognosis for return to work
Describe this fracture
- Complete comminuted fracture of the olecranon
- Communicates with elbow joint; no evidence of external communication
- Minimal displacement, multiple fragments, butterfly configuration with sharply defined margins
- This is an acute fracture. Articular involvement and pull of the triceps means internal fixation recommended.
–> Good prognosis with internal fixation depending on repair and anaesthetic recovery outcomes. These can do well because the ulna isn’t weight-bearing
What is the most common cause of fractures in horses?
a) trauma
b) developmental e.g. OCD
c) pathological e.g. secondary to neoplasia
a) trauma
May be acute e.g. kick, fall
May be chronic repetitive trauma e.g. stress fractures in racehorses
What are the typical sites for fractures caused by kick injuries?
- Splint bones
- Stifle bones e.g. tibia, patella
- Olecranon
- Head
Describe this fracture and what might have caused it
- Fracture to the lateral splint bone and also part of the third metacarpal / metatarsal bone
- Has an articular component so this fracture is unstable
- Mild displacement
- Likely caused by a kick
Describe this fracture and what might have caused it
- Fracture to the olecranon
- Articular component so unstable
- Minimal displacement
- Likely caused by a kick
What are the typical sites for fractures caused by trauma or falls?
- Head
- Vertebrae
- Long bones (femoral or cannon fractures during anaesthetic recovery especially)
- Joints during competitions (e.g. patella due to hitting fence)
What are the typical sites for fractures caused by repetitive wear and tear?
- Distal phalangeal (pedal) bone
- Middle phalangeal (pastern) bone
- Distal sesamoidean (navicular) bone
Describe this fracture and what might have caused it
- Complete fracture of the navicular bone
- Likely caused by repetitive wear and tear
Where are the most common sites for stress fractures in racehorses?
Can happen anywhere, but most common:
* Carpal bones (radius, radiocurpal, third carpal)
* Third metacarpal bone
* Middle phalangeal (pastern) bone
* Proximal sesamoid bones
* Radius
* Tibia
* Pelvis
* Vertebrae
Clinical signs of an acute, severe, or displaced fracture
- Obvious conformational abnormalities
- Severe lameness
- Pain and crepitus at the fracture site
Clinical signs of non-displaced fractures, including stress fractures, and small chip fractures
- Minimal lameness and localising signs
- Non-displaced stress fractures may present as acute onset lameness following exercise which resolves over a few days
Non-displaced, repairable fractures can progress to catastrophic irreperable fractures if not recognised and treated appropriately
Clinical signs of articular fractures
- Articular fractures normally have joint effusions
Major red flags for fractures in the history / presentation
🚩History of trauma e.g. kick or fall
🚩 Acute onset severe lameness
🚩 Acute onset joint effusion
🚩 Heat, pain, swelling, and palpable crepitus
True/false: a horse with a splint bone fracture may be able to walk normally.
True
because the splint bone is non-weightbearing
How would you differentiate between crepitus due to bone fragments and crepitus due to air/gas under the skin?
- Crepitus due to gas under the skin is usually diffuse and non-painful
- Crepitus due to bone fragments is painful and localised
Of the following diagnostic tests, which is first line for suspected fractures?
a) nerve blocks
b) radigraphy
c) ultrasonography
b) radiography
a minimum of 2 views. Important to note that some regions may not be accessible. Non-displaced fractures may not show radiographic changes (but this does mean safe!) - if in doubt re-examine and take more rads in 7-10 days.
Nerve blocks are to be avoided where possible - risk of exacerbating a fracture once blocked.
Ultrasound is mainly used in pelvic fractures in racehorses, or to locate bone chips e.g. in flexor tendons.
What radiographic view is shown here and what will it highlight?
DLPMO
This will highlight the dorsmedial and palmarolateral aspects
You want to undertake further imaging for a suspected non-displaced fracture. Which of the follows do you choose and why?
a) Gamma scintigraphy
b) CT
b) CT is gold standard, especially useful for imaging complicated fractures and neck lesions. However, limited availability and very costly.
- Gamma scintigraphy is still valuable for non-displaced stress fractures (e.g. tibia, radius, humerus) and regions which cannot be imaged well with radiography (e.g. vertebrae, ribs, scapula, pelvis)
What do the “hot spots” on this gamma scintigraphy image indicate?
These are areas of active bone remodelling
What is the most common cause of acute onset severe lameness in the horse?
a) fracture
b) tendon rupture
c) septic synovial cavity
d) pus in the foot
e) mud fever
f) arthritis
d) pus in the foot
Many cases where owners suspect fractures actually have foot abscesses
What is your primary differential in this case? How could you confirm this?
Foot abscess
* Heat, bounding digital pulses, and use of hoof testers would localise to the foot and increase suspicion of foot abscess
* Fracture is usually associated with history of trauma
What are the possible complications of a fracture with articular involvement?
Degenerative joint disease
What are the possible complications of a contaminated fracture?
- Osteomyelitis
- Synovial sepsis
- Soft tissue infection
What are the possible complications of a fracture with soft tissue involvement?
- Tendon, ligament, muscle or neurovascular damage
What are the possible complications of an unstable fracture?
- Non-healing / malunion
What are the possible complications of a fracture that damage periosteal vascular supply?
- Sequestrum formation
What are the possible complications of a fracture that results in mechanical overload of the contralateral limb?
- Laminitis
True/false: if you suspect joint sepsis, it is fine to just give the horse antibiotics.
False
A horse with joint sepsis needs joint lavage
What must you do at first examination of a suspected fracture to avoid complications further down the line?
The horse pictured had a salvageable fracture when it went to transport, but this wasn’t splinted, so the horse was weight-bearing repeatedly and then thus happened.
Arthrodesis is only an option for:
a) high motion joints
b) low motion joints
b) low motion joints
Principles of repair of articular fractures
How would you repair this fracture?
Remove the fragment (it is small so this is doable)
How would you repair this fracture?
Internal fixation - this fragment is large and needs to be screwed on
You arrive at a yard and find a horse with an open fracture. What steps do you take before transporting the horse?
- Identify and flush out wounds
- Cover and protect the wounds
- Splint the fracture if required
- Administer systemic antibiotics
- Then refer
Remember that internal fixation of open fractures is rarely successful
True/false: if a fracture can be repaired, any soft tissue injury is also likely to be fixable.
False
When the toe is up and the fetlock has dropped, as in this picture, which structures have been damaged?
- Toe up = damage to the deep digital flexor tendon
- Collapsed fetlock = damage to the suspensory ligament
- In this case, although the sesamoid fractures are fixable, the soft tissue injuries are not, therefore euthanasia is required
Which fractures should you euthanise?
Biggest challenge in fracture management for horses is mechanical load and we do not have plates and casts strong enough to support the entire load of a horse.
Should euthanise:
* Open comminuted long bone fractures
* Complete fractures of the scapula, humerus, radius, femur, and tibia in horses over 500kg
Seek advice from senior vets / referral surgeons and consult insurance company where possible.
When should you consider euthanasia?
What is the correct term for this radiographic view?
a) dorsolateral palmaromedial oblique
b) flexed dorsopalmar
c) flexed lateromedial
d) dorsomedial palmarolateral oblique
e) skyline oblique
c) flexed lateromedial
What is the correct description for this fracture?
a) closed, comminuted, non-articular
b) closed, simple, non-articular
c) closed, comminuted, articular
d) open, simple, non-articular
e) open, comminuted, articular
f) open, comminuted, non-articular
e) open, comminuted, articular
