Both the amount and rate of change involved in third phalanx displacement within the hoof capsule is clinically significant in any hoof lameness diagnosis of the performance horse.

Radiographic interpretation of displacement issues has been previously described.¹ These displacement issues have been previously attributed to laminitis concerns with little reference to displacement of the distal phalanx on non-laminitis patients.

Cases with no systemic causes include severe concussion, severe bruising, road founder and laminar trauma. Treatment protocol of displacement issues is varied and may include:

• Heart bars or other support shoes.
• Frog pads.
• Sole packs.

Limited clinical success with displacement issues is often due to secondary abscess formation resulting from edema, cellular hypoxia, bruising, tissue necrosis, tissue liquefaction, abscesses and dissecting abscesses.

Secondary Mechanical Failure

These complications further destroy the mechanical strengths of the hoof from those anatomical structures that connect and support the bony column to the hoof capsule. Secondary mechanical failure may increase both the rate and amount of displacement. Successful management of displacement should protect the anatomical structures that are being torn, compressed and sheared by this displacement while also limiting further dissection damage.

Vascular compression and eventual destruction has been recognized as playing a significant role in lameness issues resulting from laminitis.² Hypoxic necrosis of connective anatomy decreases the stability of the third phalanx while increasing the pain of laminitis. Body weight and performance forces are related to laminar strength.

Texas hoof researcher David Hood has reported that normal lamina can withstand 400 pounds per…