Page 56 - November 2017

“From an engineering standpoint, what you are really doing is putting the coffin bone on the ground and eliminating the forces on the lamellar apparatus.”
Steward creates an artificial hoof wall, sole, frog, and digital cushion by filling the space between the foot and the wooden shoe with dental impression material. This creates a stable and solid base, putting the coffin bone on the ground and eliminating forces on the lamellar apparatus. Movement will also increase lymphatic blood flow.
concept; applying proper pressure to the foot to enable this pump to keep working.”
CPR (cardiopulmonary resuscitation) can be used as an example. If you are going to do CPR on someone and they are on a bed, you must first put that person on the floor. If you press an inch with your hand, you want the chest (heart) to move (compress) an inch. If that person is on the bed, however, the whole body is going to move downward when you press. You need that person on the floor so that your pressure on the chest can move the chest and heart.
“My theory is that we are doing CPR on the horse’s foot and we want any, and all, mechanical movement to be converted into hydraulics, putting pressure on that system
so that it makes a difference; it’s active rather than passive,” he says. “Soft Ride shoes are often used for foundered horses and they can help a little, but they are too soft. There is too much cushion and they can add leverage to the damaged laminae. When the horse puts weight on the foot, it doesn’t find a bottom. By contrast, when you put the wooden shoes on the feet, you have a solid bottom that
is stable, like a cast. We usually use den-
tal impression material to fill in any space between the foot and the wooden shoe. It’s a
two-part putty that fills in the sulci (grooves or furrows) of the frog, etc. We want the solid base so that any mechanical movement is converted into hydraulics (blood and lymphatic flow).
“If you put the impression material on the bottom of the foot and then pull the shoe off (including the cast around it), the cast and impression material look exactly like the inter- nal architecture of the hoof itself. Theoretically, what we are doing is creating an artificial hoof wall, artificial sole and frog, and basically an artificial digital cushion. The ground surface
of the wooden shoe, because of the shape, is shaped like the bottom of a boat. From an engi- neering standpoint, what you are really doing
is putting the coffin bone on the ground and eliminating the forces on the lamellar appara- tus. You want to eliminate as much movement as practically possible in the laminae, includ- ing the weight/downward pressure on those attachments.” By doing these things we halt any further damage to the laminae and they can start to heal.
“You don’t want the bottom of the shoe smaller than the bottom of the coffin bone or you won’t have enough stability for the horse’s comfort,” Steward says. “In the foot, you can trade mobility for stability; those two factors are inversely related. If you increase mobility,
you decrease the stability. For example, if a per- son is walking on a pair of stilts with very small bottoms, that person would be very mobile
but not very stable. You don’t want to have the shoe smaller than the scope of the coffin bone because you want some stability. The damaged lamellar apparatus is just like a broken bone and needs to be stabilized. The foot needs a good base of support.”
You want the horse to be able to move easily, but you don’t want him to move when he doesn’t want to move—when the foot is too painful for movement and too readily damaged.
Steward is currently dealing with a horse that was snake-bit and foundered in the
other leg due to putting all the weight on the good leg. This is an example of support-limb laminitis. “The snake bitten leg is healing,
but the other hoof is now trying to come off because the horse stood on it for so long and didn’t move,” he says. “This basically created
a huge bedsore within the foot from all that constant (static) pressure and compression of the laminae and blood supply, and probably the lymphatic system as well.”
In this situation, Steward has pondered the idea of using a bubble shoe. “We could put a round ball on the bottom of the supporting foot so it cannot find stability and can (must)
54 SPEEDHORSE, October 2017
EQUINE HEALTH