How I treat LAMINITIS

If treatment during the acute stage of laminitis does not lead to full recovery, the disease will progress to the point where there is clinical and radiographic evidence of displacement of the distal phalanx (P3) within the hoof capsule.

Therapeutic trimming and shoeing have always been the "hallmark" of therapy in the chronic stage. Chronic laminitis implies mechanical failure, that in this case is the displacement of the distal phalanx relative to the dorsal hoof wall. It can be described as rotation or vertical displacement (sinking).

There has been no treatment consistently successful for all cases. Rehabilitation during the chronic stage attempts to reverse the mechanical changes that have occurred within the hoof by realigning the distal phalanx with its natural weight-bearing surface.

Rotation occurs when the dorsal parietal surface of the distal phalanx is distracted away from the dorsal hoof wall. Biomechanical forces that contribute to rotation are the vertical load of the horses weight on the digit and the forces exerted by the deep digital flexor tendon on the compromised lamina.

The distal phalanx rotation depends on the load sustained by the foot and the number of compromised lamina.

As the distal phalanx rotates, the dorsal coronary corium becomes compressed between the extensor process and the hoof wall leading to pressure-induced ischemia.

Rotation causes compression of the blood vessels and solar corium between the sole and distal phalanx. This loss of circulation in the solar corium together with the pressure on the soft tissue inhibits sole growth, leads to further degeneration and causes persistent pain.

Rotation along with the unequal hoof growth that we call chronic laminitis tends to perpetuate pressure on the sole under the apex of the distal phalanx. The goal is to prevent and/or minimize the distal displacement of the DP.

This can be partially accomplished by transferring weight from the wall to the solar surface of the foot and by reducing the pull of the DDFT. Take appropriate actions to relieve the pain, provide support and comfort in order to minimize the effects of the disease. Eliminate any pull on the DP and beveling the toe helps to increase of breakover, thereby decreasing the stress created by the leverage of the toe.

Corrective trimming of the hoof capsule attempts to realign the distal phalanx to its proper position (in respect to the ground) while maintaining an appropriate hoof pastern axis. Trimming is often complimented by a certain type of shoe. Various factors such as stage and extent of the disease, individual foot conformation, protruding sole and limited available hoof wall, may prevent realignment through trimming alone.

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The following principles should be used when preparing the hoof and selecting a therapeutic horseshoe:

(1) the palmar aspect of the hoof should be supported using all structures (sole, bars, and frog, including the central and lateral sulci);

(2) the sole should be protected without removing any portion of the sole dorsal to the apex of the frog;

(3) the hoof wall should be trimmed from the quarters to the heel only to realign the solar surface of the DP and the weightbearing surface of the hoof;

(4) the dorsal aspect of the hoof capsule should be protected by bringing the point of breakover back to 2.5 and 3.8 cm (depending on the size of the hoof) in front of the true apex of the frog;

(5) the heels should be raised to reduce the tension of the DDFT. 

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Realignment of the solar surface of the DP will reduce tension of the DDFT. Horses with instability of the DP require horse shoes that are adaptable and more compatible with the goals of hoof care. Ideally, the breakover should be close to the tip of the DP.

Horses with severe rotation and/or penetration of the sole usually have insufficient heel to realign the DP and the weight-bearing surface of the hoof by removing the heel alone.

A rubber impression material  is used to provide the sole support and acts as a spacer and support between the weightbearing surface of the hoof wall and the therapeutic shoe. It's recommended to reduce the active forces influencing separation of the lamellae and DP on the sole in the next section. This procedure relieves pain, prevents or minimizes rotation, and allows reestablishment of the normal relationship between the solar surface of the DP and the weight-bearing surface of hoof.

Severing the DDFT causes partial luxation and hyperextension of the distal interphalangeal (DIP) joint, as well as overloading of the superficial digital flexor tendon (SDFT). Severe overloading of the SDFT may result in damage to the tendon, ultimately resulting in a flexural deformity of the metacarpophalangeal joint.

Postoperative management of these horses is important to prevent or minimize these complications.

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