Joe Santos of Woodbury, Conn., debrides the hoof wall of a horse that has a keratoma at Fairfield Equine Associates in Newtown, Conn. Santos is performing a window debridement, which is slightly larger than the tumor.
Keratomas are small, benign tumors usually found between the stratum internum and the coffin bone. In rare cases, it has been seen on the dorsal aspect of the coffin bone.
The cause of keratomas is unclear, but it might be attributed to chronic irritation or trauma. Usually spherical in shape, although they also can be cylindrical, what makes keratoma distinct from other tumors is a keratinized outer shell that is the consistency of hard rubber. As the tumor size increases, it places added pressure on the sensitive parts of the inner hoof causing lameness.
Often no outward manifestations of the tumor are evident on the exterior of the hoof unless the tumor is large and quite advanced. Clinical signs can be intermittent lameness with no identifiable cause, but occasionally a discharge will erupt on the distal margins of the sole (Figure 1). A veterinarian can confirm the diagnosis with radiographs, but occasionally an MRI is the only way to identify and locate it.
Many farriers go through their entire careers without being involved in a keratoma case, but Joe Santos from Woodbury, Conn., has worked on dozens. He is the go-to farrier at Fairfield Equine Associates in Newtown, Conn., one of the leading equine referral hospitals in the Northeast. They get the tough cases that are difficult to diagnose and treat. After dealing with so many cases, they have developed a very successful treatment protocol for handling keratoma cases.
Surgically removing the entire mass is the only way of dealing with the condition. After positively identifying the location and the size of the mass, Santos prefers to build a shoe that will support and protect the integrity of the hoof capsule.
He prefers an egg bar shoe, which easily can be modified with a heart bar for additional support. You also can weld in plates for additional bars to provide protection to the bottom of the foot. Santos draws additional clips in strategic places (Figure 2) to prevent wall movement. Clips are usually placed on both sides of the debridement. Additional clips at the toe or the opposite side of the shoe might be necessary to make sure the hoof capsule is stabilized.
The vet determines how deep the resection will go. If the resection is going deep, additional protection in the form of plates can be welded to the shoe. Santos prefers to nail on the shoe before any debridement efforts to spare the horse from hammering on a now possibly very sensitive foot and to lessen the contamination of the debrided section.
Debridement of the wall usually takes two forms. Often the tumor is a spherical shape and is midway up the hoof wall. For this tumor, a window debridement just slightly larger than the tumor is made. Sometimes, though, the tumor will take the shape of a long, vertical cylinder that may extend distally from the coronary band to the sole. It’s necessary to remove the hoof wall to expose all of the mass so the tumor can be eradicated.
The procedure for treatment is to first nail the treatment shoe on. Next, the leg and foot is scrubbed to reduce bacteria. A tourniquet is applied above the ankle to limit bleeding. The vet then blocks the foot to desensitize it. The boundaries of the debridement area are drawn with a marker (Figure 3).
Santos prefers to nail on the shoe before any debridement efforts to spare the horse from hammering on a now possibly very sensitive foot…
Under guidance from the vet, Santos usually uses his Dremel tool to penetrate the hoof wall down to the insensitive laminae (Figures 4 and 5). Then, the surgeon takes the final step and pulls the center section of the wall from the foot (Figures 6 to 8). In some instances, the mass will cling to the hoof wall and come out in its entirety. In other cases, further tumor debridement is necessary.
A 10-day stay in the hospital is mandatory. What struck me as interesting was that immediately after the surgery, sterile maggots were introduced to the site to consume any tissue that would inhibit healing. Maggot therapy is often used when the healing process has bogged down and needs to be cleaned up. By being proactive with the maggots, this doesn’t happen and recovery is much smoother.
After four days, the maggots are removed and a steroidal cream is applied to the wound.
At day 8, sugardyne is applied and Santos covers the foot with a bandage made of Equicast (Figure 9). Before applying the cast, Santos lines the perimeter of the debrided hoof wall with butyl tape (Figure 10) to seal the site and prevent moisture from entering the wound. He reports outstanding results using this method.
The main consideration for shoe application is how sound the horse is and whether it is experiencing any pain. In severe cases, a shoe that completely immobilizes the hoof capsule might have to be used for two or three cycles.
If the horse is doing well, the plan is to get it back into an open heel shoe as soon as possible. The wishes of the owner also play an important part as some want to return the horse to work quickly. Others are more cautious and want to wait until the vet is positive it is healed.
Santos lines the perimeter of the debrided hoof wall with butyl tape to seal the site…
The horse is now sent home. The horse is put on a 4-week schedule for Santos to re-shoe and for the vets to evaluate healing. He uses several different types of shoes, depending on the amount of wall loss and the desire of the client to regain use of the horse.
In cases involving simple window debridement, the horse can go back into a regular open-heeled shoe after the second or third reset. In severe cases, some type of bar shoe may be needed for months.
Depending on the case, some horses return to immediate soundness and return to light work within weeks. Other more complicated cases may require as much as a year, depending on the owner’s wishes.