Keratoma and Septic Pedal Osteitis

Question 1

What is a keratoma? Describe the pathogenesis

Answer 1

• Hyperplastic keratin mass within the hoof
• Originate from epidermal horn producing cells of coronary band
• May be a benign neoplasm
• Grow distally towards the toe with the hoof
• Act as a space occupying lesion within the hoof capsule
  
  • Pressure necrosis in adjacent distal phalanx
  • Hoof deformation
  • Loss of white line integrity → entry of bacteria → hoof abscess

Question 2

Where are keratomas most often found? What causes them?

Answer 2

Most common in toe region of hoof

May occur following an insult to the germinal cells at the coronary band
* Hoof abscess
* Trauma
* Hoof crack

Question 3

What history is commonly associated with keratomas? What do you expect to find in your clinical exam?

Answer 3

• Maybe mild intermittent long term lameness
• Usually recurrent severe lameness
  
  • recurrent hoof abscesses at the same location

Clinical exam
* Raised digital pulse (single foot)
* Possible hoof wall distortion
* Deviation of white line with ‘Cork like’ growth visible
* Localised pain with hoof testers
* Drainage from abscess

Lameness abolished by peri-neural anaesthesia of the foot

Question 4

How do you diagnose a keratoma on radiography?

Answer 4

• Dorso 60°proximal – palmar/plantar distal oblique view (upright pedal)
• Smoothly demarcated radiolucent lesion in the distal border of distal phalanx

Question 5

What are the 2 forms of keratomas?

Answer 5

Question 6

How are keratomas treated?

Answer 6

Surgical excision - partial hoof wall resection through dorsal hoof wall

Question 7

What is the prognosis associated with a keratoma?

Answer 7

• Takes several months for hoof defect to grow out
• Good prognosis
• Keratoma recurrence in <20% cases

Question 8

What is septic pedal osteitis? How does it occur?

Answer 8

Infection in the pedal bone

• Follows a solar penetration which penetrates distal phalanx
  
  • Usually a nail
• Bacteria enter bone and cause osteomyelitis
• Sequestrum formation follows

Question 9

What history is commonly associated with septic pedal osteitis? What do you expect to find in your clinical exam? How is it managed?

Answer 9

• Nail penetration into sole
• Raised digital pulse (single foot)
• Discharge and pain with hoof testers at the site of penetration
• Initial radiographs may be normal
  
  • Ideally radiograph with nail still in place

Management
* Managed with poultice, abx, NSAIDs, TAT
* Lameness does not resolve
* Septic pedal osteitis diagnosed on repeat radiographs

Question 10

What can you see on this radiograph?

Answer 10

Septic pedal osteitis

Question 11

What surgical treatment is available for septic pedal osteitis?

Answer 11

Surgical excision of infected part of the pedal bone
Hospital plate on top of shoe to cover sole

Question 12

What prognosis is associated to septic pedal osteitis?

Answer 12

Excellent