HOW TO GLUE ON THERAPEUTIC SHOES
Stephen E. O'Grady, BVSc, MRCVS
Edgar Watson, CJF
Reprinted with permission from the American
Association of Equine Practitioners.
Original printed in the 1999 AAEP convention proceedings
Introduction
Attaching a shoe to a compromised equine hoof wall has
presented a challenge to both veterinarians and farriers. The
discomfort or trauma caused by the concussion of driving a
nail may prohibit the conventional use of horseshoe nails in
many foot injuries. Some conditions that may warrant a
non-nailing (alternative) technique are acute or chronic
laminitis, extensive hoof wall separations (white line
disease), resections or avulsions, third phalanx fractures and
severely damaged heels resulting from the long toe - underrun
heel syndrome. A polymethylmethacrylatea (composite) was
introduced in 1988 for the repair of hoof wall loss and
cracks. This acrylic has been modified to provide flexibility,
and at the same time, adheres well to hoof walls.1
More recently; this material has been used with excellent
results to attach therapeutic shoes (or any shoes) to the
hoof. This report describes a method that utilizes the ground
surface and perimeter of the foot and differs from other
described methods, which have used only the outer surface of
the hoof wall. Use of the ground surface and hoof perimeter is
especially advantageous if there is significant hoof wall
loss. Non-nailing alternatives are not meant to replace
conventional horseshoeing but are a temporary measure that can
be used to attach a shoe while treating an underlying hoof
problem.
Method
The procedure is relatively easy to master, but strict
attention must be paid to preparation of the hoof. Sedation of
the animal is rarely necessary. Local anesthesia can be used
if the horse is unable to stand on the opposite limb as in the
case of severe laminitis. The hoof is leveled and the heels
are moved back toward the widest part of the frog if possible
using a rasp. Any adjustments in hoof angle or medial -
lateral balance are made at this time. All loose ex-foliating
sole is removed down to solid, live sole with a hoof knife.
Any separations or fissures in the sole wall junction (white
line) are explored, using a bone curette and/or a Dremel toolb.
If these tracts can't be removed or go too deep, they are
packed with a medicated puttyc with a tail leading to the
outside for drainage if necessary to prevent a possible
abscess. Aluminum shoes have be used predominately because
they are light and easy to work with but steel shoes can be
used if desired. The shoes are fitted to the foot at this
time. Bar shoes (aluminum or steel) can be used if appropriate
for the condition being treated. The shoes are fit to extend
slightly beyond the hoof wall from the widest part of the hoof
to the heel. This provides a base for the bead of composite
that will be smoothed out onto the hoof wall. Quarter clips
are recommended to keep the shoe in place when it is seated in
the composite. The bearing surface of the shoe is sanded and
set aside to remain clean. The final preparation of the ground
surface of the foot and one inch up the outer hoof wall is
accomplished by sanding with a drum sander attached to a
Dremel tool. The prepared surface is washed with acetone or
denatured alcohol, dried with a heat gun and placed in a clean
cloth boot.2 A 4-inch by 4-inch square of
fiberglass is pulled apart so that the strands resemble "angel
hair" and is mixed with the composite. This makes the Equilox®
firmer and easier to mold, adds structural strength to the
composite and enhances the flexibility of the bond between the
shoe and the hoof wall. Using gloves, a layer of the plain
composite is applied to the area of the hoof to be bonded,
working it into the surface. This will improve the contact
area to be bonded. The combined composite and fiberglass is
then picked up and molded (rolled) into a tubular structure.
One roll is placed on either side of the prepared foot
starting at the quarter and extending to the heel. With hoof
wall loss, a smaller roll is placed on the available ground
surface. The fitted shoe is then placed on the hoof and
pressed down firmly into the desired position. A small amount
of Equilox® will bulge out on either side of the shoe forming
a bead. Using a finger, this bead is spread on the outer hoof
wall (forming a lip) and on the inner sole (next to the shoe).
The material on the solar surface is molded to the existing
concavity of the sole where it will adhere and strengthen the
existing sole.
The foot is covered with plastic wrap, which is held in place
with a co-adhesived bandage. Molding the material over the
sole can be continued through the covered foot. The foot is
held up until the composite has hardened (usually 1-2 min).
Any composite material covering the frog is removed and the
material on the perimeter of the hoof wall is shaped and
smoothed with a rasp. It is easy to raise the heels or adjust
the foot angle in any direction by just molding the tubular
structure of the composite thicker or thinner to achieve the
desired effect. .
To remove the shoe, hoof nippers are carefully placed between
the shoe and the hoof. One or two cuts are made through the
glue at the heel and the shoes are peeled forward. The glue-on
procedure can be repeated at regular intervals as necessary.
Results
We have shod 50 horses in this manner in our combined
practices. These have included horses suffering from chronic
laminitis, hoof wall separations, a third phalanx fracture and
horses with lameness due to chronic heel soreness (long toe -
underrun heel). Horses with laminitis and severe hoof wall
loss showed immediate improvement after the procedure. Horses
with lameness due to heel sensitivity (bruising) became sound
and were able to resume work. The bonding capabilities of this
composite appeared superior to previous methods (products)
used.
Discussion
Glue-on technology has been available since 1986.The
techniques have employed the outer hoof wall by using a cuff
or plastic tabs for attachment. These have proved cumbersome
and unpredictable, but the technology continues to be refined,
as new products become available. The method described here
uses the ground surface of the hoof with the shoe glued
directly to the bottom of the foot. Moreover it uses a product
that was not originally developed for this purpose, but which
appears to have superior ability to adhere to the hoof. This
method can be used providing there is sufficient ground
surface on the lateral and medial side of the hoof. In the
case of the laminitic horse, using radiographic guidance, the
heels can be raised or lowered to create a more parallel
relationship between the third phalanx and the ground. This is
accomplished by the varying amount of composite used to create
the tubular structure thereby changing the angle of the shoe
relative to the foot. This allows weight bearing to be
localized to the heels and relieves pressure from the lamina
in the toe area. Hoof wall separations have historically been
treated by resection and acrylic repair so that nails can be
placed in the affected area to attach the shoe. However, the
disease process often will continue under the repair,
prolonging the time required for the hoof wall to grow out. By
gluing the shoes to the ground surface of the foot, the
resected area can be left open to be debrided and medicated
regularly. With a third phalanx fracture, an aluminum bar shoe
is used and a continuous rim can be formed around the entire
perimeter of the hoof using the composite that is pressed out
when the shoe is set in place. This provides excellent
stabilization of the fracture without the trauma of nailing.
Horses with bruised heels resulting from the long toe underrun
heel conformation improve immediately. It is our contention
that the discomfort associated with these weak heels is caused
by trauma, heel movement against the shoe and lack of
sufficient hoof wall in this area. This movement causes
continual and excessive wear at the heels leading to further
pain and little chance for regrowth. A deep "trough" cut in
the heel of the shoe further attests to this movement. It is
our feeling, that by attaching the shoe directly to the heel,
movement is stopped and the heels are stabilized. The
interface provided by the composite between the heel of the
foot and shoe may also reduce concussion exerted on the heels.
This may eliminate pain and allow the heels to strengthen and
regrow. Flat feet will invariably accompany the long toe
underrun heel conformation. Composite spread over the sole
during the procedure adheres to it and forms a "false" sole
that will provide additional protection.
A drawback of this method is that it can be expensive and time
consuming, and success depends on proper hoof wall preparation
and composite application.2. However, it offers an
improved method to attach horseshoes to the ground surface of
the equine hoof when a non-nailing alternative is indicated.
Moreover it requires no special shoes and is accomplished
using ordinary shoes and composite.
References:
1. Moyer W, Sigafoos R. Equine hoof wall repair. Trenton:
Veterinary Learning Systems, 1993; 6.
2. Moyer W, Sigafoos R. Preliminary experience and uses of
composite hoof wall repair, in Proceedings. 37th Annu Conv Am
Assoc Equine Practnr 1991.
Footnotes:
a. Equilox® - Equilox Int'l 110 NE 2nd Street, Pine Island, MN
55963
b. Dremel® Dremel Tool Co. Emerson Electric, 4915 21st.,
Racine, WI 53401
c. Keratex® putty - Advance Equine P.O. Box 54 Versailles, KY
40383
d. Vetwrap® - 3M Animal Care Products St. Paul, MN 44144-1000
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