Chronic laminitis challenges veterinarians and farriers to improve function in a foot with substantial, possibly permanent structural changes. Chief among these is displacement of the third phalanx (P3), which is responsible for the hallmarks of chronic laminitis: chronic lameness, recurrent foot abscesses and abnormal hoof wall growth.

Rotation of P3 is the most common form of displacement. With rotation, weight bearing is concentrated at the apex of P3, which causes focal pressure on the solar corium — the inner, sensitive laminae with its associated circulation responsible for producing the horny sole — in that area.

Pain is the most obvious and urgent result, but loss of blood flow to the solar corium (and probably of the tip of P3) is also an important consequence, because it retards sole growth.

Beyond further damage to the laminar attachments in the dorsal hoof wall, P3 rotation can cause excessive pressure on the coronary corium through the extensor process. The resulting loss of blood flow alters the rate, and in severe cases, even the direction of horn growth from the coronary papillae in this area. These problems can be eased only by restoring the alignment of P3 relative to the bearing surface of the foot (that is, to the ground surface).

For a long time, the primary treatment for chronic laminitis has been therapeutic trimming and shoeing, which will continue to be crucial for effective management. However, the principles must be thoroughly understood and skillfully applied. The goal is to restore P3 to its…