Solar bruising and corns

Question 1

Pathogenesis of sole bruises

Answer 1

Trauma:
* Blunt trauma to the solar surface of the hoof during locomotion or a kick
* Haemorrhage into the sensitive tissues of the foot

Inflammation:
* Tissues become inflamed, vascularity increases
* This leads to increase in tissue fluid

Pressure:
* Increased fluid content of inflamed tissues
* Hoof is a sealed, non-compliant structure and thus leads to focal increases in pressure

Question 2

Clinical signs & differential diagnoses

Answer 2

Acute, severe unilateral lameness
* Ddx – subsolar abscess, pedal bone fracture

Mild bilateral (or quadrilateral) pain
* Ddx – laminitis, bilateral forelimb lameness

Examination findings:
* Increased digital pulses to affected hooves
* Increased hoof temperature
* Sensitivity to hoof testers

Question 3

When is sole bruising called a corn?

Answer 3

• A “corn” is just bruising at the “seat of corn” (located between the hoof bar and wall, near the heel)
• Hoof testers will localise the focus of pain
• Can be dry or suppurative as tissue fluid leaks through the epidermal tissues

Question 4

Initial management if lameness is acute, unilateral or severe

Answer 4

• Likely manage as a subsolar abscess and assess response
  – poultice, NSAIDs, rest
• If the horse has bruising, the lameness will
  improve rapidly without any drainage of pus

Question 5

Initial management if lameness is mild or multi-limb

Answer 5

• Non-specific management including box rest and
  NSAIDs (phenylbutazone)
• If the horse has bruising, the lameness will
  improve rapidly

Question 6

If there is significant haemorrhage what can solar bruises progress to and why?

Answer 6

• subsolar abscesses
• blood is a very good culture medium

Question 7

Risk factors for solar bruising

Answer 7

Surface:
* Uneven or highly concussive surfaces

Shoeing/farriery:
* Barefoot horses will be more prone
* Long shoeing interval (particularly corns)

Activity type:
* Horses used for hacking will be more likely

Activity level:
* Repetitive concussive forces

Conformation:
* Horses with flat foot and low heel conformation

Question 8

Prevention

Answer 8

Maintain shoeing intervals → 6 weeks is the “norm” but consider individual variation

In at-risk horses or at-risk environments consider ways to prevent concussion and contusion:
* Shoes fitted to horses that are barefoot
* Pads fitted between the shoe and the hoof
* Packing material injected between the pad and the sole

Horses with poor hoof conformation should be actively corrected:
* Sparing the heel when trimming
* Avoid working on firm or uneven ground