Complete Article

EARLY SUCCESS:
After Josie nearly tore
off her right hind hoof
in a 1992 pasture
accident, she was
given to Ric Redden,
DVM, of the
International Equine
Podiatry Center in
Versailles, Kentucky.
Since then, the little
grade mare has been
instrumental to
Redden’s pioneering
work in equine
amputations and
prosthetics. Josie is
shown here, about five
months after her injury,
just before being
turned out for the first
time with her new
prosthetic limb.
Watching the mare
gallop in her pasture
that day was “the
most exhilarating
experience of my
professional career,”
says Redden.
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AN
ARTIFICIAL LEG
TO STAND ON
o c t o b e r
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equus
c
Advances in amputation and prosthetic devices
offer a viable alternative to euthanasia when a horse’s limb
is damaged beyond repair.
o c t o b e r
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doesn’t suit a horse and requiring heroic care.
Not so, say the surgeons who have been working to modify and improve the procedure. “It’s an
option for owners, and one I wish more would consider,” says Ted Vlahos, DVM, an equine practitioner from Sheridan, Wyoming. “But they have to
know what’s in store for them and their horse if
they make that choice. This isn’t a minor procedure. It’s no more benign than a person having his
leg amputated.” In short: Removing any portion of
a horse’s limb and replacing it with a prosthesis
requires a significant commitment of money and
time and no small measure of personal fortitude.
There are ample opportunities for catastrophic
complications, and a horse with a prosthetic limb
can never be ridden. He can, however, maintain a
reasonably good quality of life.
By Joseph and
Carol Berke with
Christine Barakat
Likely candidates?
Horses who experience sudden catastrophic
injuries and those in the early stages of a chronic
condition are the best candidates for amputation
and prosthetic repair.
“A horse who suffers a sudden, serious breakdown is usually an athletic horse with nothing
else wrong with him,” Vlahos says. “He’s in pretty
good physical condition, aside from the injury itself, and typically, he has three other very good
legs.” Such a horse, according to Vlahos, usually
has the physical reserves to handle not only surgery, but the prolonged recovery period and adaptation to a new way of life. Ric Redden, DVM, of the
International Equine Podiatry Center in Versailles,
Kentucky, agrees: “An athlete that shatters his cannon bone, totally destroying the blood supply to
the lower limb, would be the perfect candidate
because his body and mind are quite healthy.”
In contrast, a horse who has lived for months or
years with laminitis or severe arthritis isn’t going
PHOTOS COURTESY, RIC REDDEN, DVM
T
he past two decades have seen remarkable
progress in equine orthopedics. Improvements in surgical techniques and equipment as well as breakthroughs in drug
therapy are preserving the lives of horses whose
leg injuries once might have been seen as so
severe that euthanasia was the only option. Yet
for all that can be done to repair and rehabilitate
equine limbs, some equine afflictions still
seem beyond the reach of medical treatment.
Aggressive arthritis can quickly cripple a oncehealthy athlete. A bone-eating infection can
destroy a joint in days. And laminitis remains a
baffling, painful and deadly condition. How can
horses so stricken ever return to comfortable and
relatively productive lives?
Largely through the efforts of a small group
of veterinary surgeons, amputation and prosthetic limbs are beginning to emerge as a reasonable option. “Horses can live quite happily with a
prosthetic limb for years and years, running, bucking, breeding and acting like a horse in every
way,” says Barrie Grant, DVM, of San Luis Rey
Equine Clinic in Bonsall, California. An equine
surgeon, Grant has performed more than 25
amputations, and one of his patients has had a
prosthetic limb for 20 years. “We’ve conquered
many of the problems we faced in the past and
continue to make breakthroughs,” he says. “In
fact, one of the biggest hurdles we still face is
convincing people that it can be done.”
Historically, horsemen have regarded amputation and prosthetic repair as extreme options of
last resort that, at best, offer only marginal success. It is commonly believed that a horse with an
amputated limb will develop laminitis in his opposite “good” leg—the result of its having to bear
more than its fair share of weight—or that he will
hobble pathetically for a few years, living a life that
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57
techniques
An evolving science
c
FOR MORE
INFORMATION:
To read an
account of an
earlier effort to fit
a horse with a
prosthetic limb,
go to “Boitron:
The Horse With
the ‘Bionic’ Leg,”
EQUUS 100.
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The equine limb is a marvel of engineering.
A column of bone, sinew and skin no larger
than six inches in diameter, it supports
thousands of pounds of force at high speed,
absorbing shock and adapting to footing that can
change in an instant. Replacing a horse’s leg
with a device that is equally versatile is not yet
possible, but prosthetists—the professionals
who make artificial limbs for people and animals—work to incorporate the latest technological advances into devices that do more than
simply offer support.
“The idea is to mimic the mechanics of the
leg as much as possible,” says Barrie Grant,
DVM, of San Luis Rey Equine Clinic in Bonsall,
California. “It’s important that a device be able to
bear the weight of the horse and have some
shock absorption, which cuts down on pressure
on the stump.” The more comfortable the prosthesis is, Grant continues, the more weight the
horse will put on it, meaning the less stress the
opposite limb will have to bear.
Virtually all of the prosthetists who work with
equine surgeons construct artificial limbs primarily for people. “The real advances in prosthetic limbs, such as spring-loaded devices, are
being made in the human field,” Grant explains.
“And a good prosthetist will try to incorporate
them into an equine device.”
The first step in creating an equine prosthesis is to make a cast or mold of the stump so that
a socket can be custom built. Fit is very important for the comfort of the horse and the health
of the stump. Most equine prostheses are made
from various combinations of carbon graphite,
fiberglass, stainless steel and various plastics.
They usually are suspended from the joint above
the amputation site and secured with straps
and/or harness systems.
Ted Vlahos, DVM, of Sheridan, Wyoming, has
worked with a local prosthetist to develop an
equine prosthesis that is intended to be more
comfortable for the horse and less complicated
for the owner to remove and replace. “Our boot
has clamps to hold it in place, much like a ski
boot,” Vlahos says. “We think it’s much easier
to work with.”
to be in the best physical condition. “In those
cases, the horse commonly has overused the good
limb; it’s been bearing more than its share of the
weight for a while,” Vlahos says.
Immediately after amputation that good leg is
under even more stress, which can have disastrous consequences. “When horses founder in the
opposite leg after amputation, it’s typically because that leg was already damaged from overuse,” Vlahos continues. “That’s one of the biggest
reasons why the decision to amputate needs to be
made sooner in the course of chronic conditions,
rather than later.
“Amputation is still a salvage procedure—
something you do when there is no other way to
save the horse. But waiting too long to reach that
decision can really reduce the odds of success.”
Vlahos adds that since surgeons have begun amputating limbs earlier in the progression of chronic conditions, the incidence of laminitis in the
opposite leg--one of the more common complications of the procedure--has dropped dramatically.
Several additional factors contribute to the
success of an amputation and prosthetic repair:
■ The location of the amputation: In general,
hind-limb amputations are less taxing for a horse
because his rear legs bear a smaller percentage of
his overall weight. In addition, the lower on the
leg an amputation is performed, the better the
likely outcome because more of the limb’s joints
remain intact. That makes it easier for the horse to
maintain his natural gait and to get up and down.
Amputations above the knee or hock currently
aren’t feasible. “But we will eventually get there,”
Redden says.
■ The horse’s breed and size: “The best
breeds for the procedure are the smaller, lighter
breeds,” says Gayle Trotter, DVM, an orthopedist
at Colorado State University. “The larger breeds
are more vulnerable to breakdown of the soft tissue in the support limb while they are adapting to
the prosthesis.”
■ The horse’s attitude: “Those who have longterm success with a prosthesis are able to adapt
quickly to rapidly changing situations and stimuli,” says Grant. For instance, periodically in the
months following surgery, the horse will be positioned in a hanging sling for cast changes and
prosthesis adjustments. He’ll also have to learn
how to lie down, stand up and move with a prosthetic limb. “Unfortunately, it’s tough to know how
a horse is going to adapt until you’re actually in
the situation,” says Grant.
■ The owner’s wherewithal: The initial surgery
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and hospital stay will cost between $10,000 and
$15,000 and the prosthesis will add another
$5,000. “Beyond the costs, there is an enormous
commitment of time that’s required,” says Vlahos.
“You will never sell this horse and he will require
hands-on care every day for the rest of his life.”
Perhaps Grant sums it up best: “If you’re not going
to go into it fully committed and prepared to see
it through for years and years—physically and
emotionally as well as financially—don’t do it at
all. It’s not fair to the horse.”
The details of surgery
Before an amputation is performed, the
horse must be medically stable, particularly in
the case of an acute injury. “I don’t think it’s a
great idea to rush [a prosthesis candidate] from
the racetrack to surgery, even if you know that’s
where you’ll end up,” says Grant. “It’s much
smarter to apply a cast and give the horse a day or
two to stabilize while you get yourself organized
for what lies ahead.”
Grant uses that time to condition the horse to
the sling that will become a critical part of the recovery process. With the injured limb stabilized in
a full-length splint or cast, the horse is lightly sedated and placed in the sling for one or two short
MODEL PATIENT:
Twelve years after
losing her hind hoof in
an accident, Josie is
“thriving on very little
maintenance, beyond
replacing her artificial
leg whenever she
wears one out,”
reports Ric Redden,
DVM. “She is turned
out full-time with other
horses and has been
since she got her very
first prosthetic.” Josie
is now wearing her
fourth artificial limb
(above), which Redden
describes as one of
his simpler designs.
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STATE OF THE ART:
After an amputation
was performed on a
Thoroughbred mare
named Callie, X-ray
images show that
the coffin bone has
been removed.
For protection and
comfort, frog tissue
was removed from
Callie’s remaining
hooves and grafted
onto her stump. The
frog tissue, which
eventually hardens,
continues to grow and
requires periodic
trimming just as it
would on a
normal hoof.
Supported by a sling,
Callie has her
prosthetic limb fitted.
The sling plays a
critical role in the
recuperation of an
equine amputee,
providing support
immediately after
surgery and later on in
the recovery period
when medical
treatment is necessary
or adjustments
are made to
the prosthesis.
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sessions. These practice runs not only accustom
the horse to the sling, says Grant, they provide
valuable insights into how accepting the patient
will be of the changes and stresses that lie ahead.
On the day of surgery, the horse is placed under general anesthesia and positioned on either
his side (lateral recumbency) or his back (dorsal
recumbency). To determine how much of the limb
will be removed, the surgeon examines radiographs of the area and visually inspects the tissues to determine which are healthy and which
are dead or dying. “You want to leave only perfectly healthy tissue and tissue that has ample blood
flow,” says Grant. Typically, he removes the leg an
inch or so above a damaged joint. For an injury
that is elsewhere on the lower leg, he amputates
an inch or so below the next highest joint to minimize stress on the remaining bone.
Prior to the amputation, the surgeon inserts
two metal pins in the bone near the site. Technically known as transfixation pins, they will transfer the horse’s weight around the surgical site to a
temporary prosthesis, allowing him to walk immediately after surgery without placing weight on the
healing stump. The pins are placed at a 30-degree
angle, a recent modification that has improved the
success rate of the procedure. “Pins used to be
placed in the bone parallel to the ground, and
fractures at the pin site during recovery from
anesthesia used to be a common complication,”
says Vlahos. But when surgeons began placing the
pins at an angle, the incidence of fractures
dropped dramatically. “There is simply less concentration of stress on the bone when the pins are
placed at 30-degree angles,” Vlahos explains.
With the pins in place, the amputation begins.
Typically, the surgeon first creates an elliptical or
semicircular flap of tissue on the fleshy back side
of the limb. This flap includes skin, subcutaneous
fat and tissue and, if it is healthy, the stump of the
flexor tendon. Later, this flap will be pulled over
the bone end and sutured to the front of the limb
to create a covering.
As the operation proceeds, the surgeon isolates
and severs nerves, using a cryosurgery probe to
freeze the endings, a technique that will minimize
pain following surgery. The suspensory ligament
is cut and then the bone. The end is smoothed and
rounded and covered with wax to reduce bleeding.
The next step involves the most recent—and
what some surgeons consider the most important—innovation in equine amputation: frog grafting and transplantation. Developed by Redden, the
technique involves taking healthy frog tissue from
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THE
REPLACEMENTS:
Grafted frog tissue does require periodic attention:
It grows just as it does on the hoof, so it must be
trimmed regularly to ensure the prosthesis’ fit.
Once the amputation is complete, the surgeon
applies a fiberglass cast that incorporates the temporary prosthesis attached to the transfixation
pins. The horse is then placed in the all-important
sling to recover from anesthesia. “Our biggest complication used to be fracture of the limb during
recovery,” says Vlahos. “However, we’ve all but
eliminated the incidence of that with angular pin
placement and sling recovery.” If all goes well, the
horse bears weight on the prosthesis immediately
following surgery and is able to walk comfortably.
“I’ve had experiences with horses who lived
with extremely painful conditions for months before amputation,” says Grant. “They wake up sore
after surgery, but the deep gnawing pain is gone
and you can almost see the relief on their faces.”
Initially, a horse who
has undergone
an amputation wears a
temporary prosthesis
until the stump heals.
Young horses,
however, may go
through several
temporary artificial
limbs as they grow
and develop.
When healing and/or
growth is complete,
the horse is fitted with
a permanent prosthesis
(below), the exact
design of which varies
from case to case.
COURTESY, TED VLAHOS, DVM (TOP)
Recovery and aftercare
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the patient and grafting it into the stump either at
the time of surgery or, in some cases, one or two
weeks afterward. As the frog tissue grows, it
forms what Redden describes as “a wonderful,
tough, resilient material” that protects the bottom
of the stump. Prior to frog grafting, the amount of
muscle and tissue that remained after surgery
wasn’t always sufficient to adequately shield the
bone end. The result was painful pressure and
trauma that eventually necessitated euthanasia.
Complete recovery from amputation surgery
can take anywhere from six months to a year,
during which time the horse likely will live at the
equine hospital for intensive care and management. The fiberglass cast and temporary prosthesis will be refitted at least once, and possibly
several times, as the stump heals. Each cast
change requires that the horse be sedated and
placed in a sling. The pins are removed once healing is well under way, which takes between eight
and 12 weeks. The horse then will bear weight
directly on the temporary prosthesis. In the best
cases, the horse is fitted for a permanent prosthesis three months after the pins are removed; six
months following surgery, he can be turned out in
a small enclosure with quiet companions.
During the recovery period, any number of complications can arise, from infections to stump pain
to pressure sores. Some horses, says Grant, never
learn how to lie down with an artificial limb. “If
you get a horse that won’t lie down, it can be a big
problem,” he says. “It puts a lot of stress on all the
limbs. I’d love to teach one to lie down on command before an amputation. I think that might
avoid some of those problems.” Vlahos says he
isn’t comfortable labeling a procedure a success
until a year has passed. “I think that if we can get a
horse through the first year without complications,
then there’s no reason to think he can’t live out his
life comfortably,” he says.
Once an amputee goes home, his daily care isn’t
complicated, but it does require extreme diligence
and commitment. Most prosthetic limbs have to be
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case study
To save a filly
c
When complications from a contracted
tendon destroyed the circulation in his 3week-old filly’s lower leg, Jim Perkins
thought all was lost. “The hoof just came
off and a few days later, the fetlock joint
fell away,” he says.
The Amarillo, Texas, horseman worked
to prevent the stump from becoming
infected. He also devised a crude prosthesis for the foal, using PVC pipe. “She was
getting around on the prosthesis, but I
could tell she was in pain,” Perkins says. “I
wanted to give her a chance, but I was
preparing to make the tough decision to
put her down.” The filly’s grandmother was
a champion cutting mare and both Perkins
and his wife had hoped that the youngster
someday would be an important addition
to their large breeding program. They
understood that their plans for her might
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never be realized, but their emotional attachment to her made it extremely difficult for
them to consider euthanasia. “To my wife and
myself, these horses are like children,”
Perkins says. “We brought her into this world,
so we feel it’s our responsibility to take care of
her while she’s here and do everything we can
to help and not give up.”
Then the Perkins’ daughter saw a televised
segment about veterinarian Ted Vlahos on
“Good Morning America” and immediately
called her father. Vlahos is one of a few surgeons in the United States who outfits horses
with prosthetic limbs. Within days, the filly
and her dam were on a trailer for the 900-mile
trip to Vlahos’ clinic in Sheridan, Wyoming.
Amputation wasn’t necessary, but Vlahos
performed skin and frog grafts to fashion a
protective stump, and he put pins in place to
support the filly’s bad leg on a temporary prosthetic while the grafts healed.
After surgery, the foal stood without pain
for the first time in her life, and within days
she was running and playing with her dam.
The filly was weaned at Vlahos’ clinic
when she was 5 months old and returned
home at 7 months. She was named
Dulces Vlahos, says Perkins, because
“When it was time to name her, Dr.
Vlahos had had her longer than we did.”
Now on her second prosthesis—she
will have several more made as she
grows—the filly lives a typically equine
existence on the Perkins’ ranch. “She is
turned out with other horses and can trot
and gallop and will even kick at you if she
puts her mind to it,” says Connie Perkins.
“She is just thriving.”
The Perkins know that Dulces will
never be a “normal” horse and will
always require special care. “I don’t have
a problem taking care of this little one
every day for the next 25 years,” says
Perkins, who has spent nearly $80,000 on
all the combined veterinary expenses for
Dulces and about $4,000 more for each
prosthetic limb. “There’s no question in
my mind that she is worth it.”
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removed daily or every other day so the
stump and its protective sock can be
cleaned. The stump also needs to be inspected for signs of trauma or pressure.
“You have to be vigilant and catch
things the minute they appear,” says
Vlahos. “It’s a daily commitment and
one you might not be comfortable leaving with anyone else. Vacations could
be difficult.”
Prosthetic devices typically require
padding at the stump, and most owners
quickly become skilled at choosing and
arranging the cushioning material,
says Grant. “We learn a lot from owners about padding,” he says. “They’ve
experimented and found what works
best for their horse.”
As for the other aspects of routine
management and care, not much will
change for a horse with a prosthetic
limb. He may require the use of a sling
to support his weight and aid his balance when he’s trimmed and shod.
Otherwise, “these horses can be turned
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out in a quiet herd,” says Grant. “They
can buck and play and act like a horse.”
They cannot, however, be ridden. “I
would never recommend that anyone
try to ride a horse with a prosthetic
limb,” says Vlahos. “That would be
unsafe for the horse and the rider.”
Most amputees are used for breeding,
although many surgeons recommend
artificial insemination whenever possible, to reduce the risk of injury.
he practitioners who perform
amputations and prosthetic
fittings are often reluctant to quote
percentages regarding success rates
and average life span following the
procedure. “Each case is so incredibly
different,” says Grant. “You really can’t
say that what happened with one
horse is going to happen with the
next—good or bad.”
More hard and fast scientific
answers may be available soon,
though, says Vlahos, who helped author
T
a large retrospective study with
“encouraging results.” The study has
been accepted by a veterinary journal
and is awaiting publication.
What is available now, however, is
an honest portrayal of what lies ahead
for the horse as well as his owner.
“I’m as enthusiastic as anyone about
the procedure,” says Vlahos. “It’s a
very, very useful and feasible option
that can save the life of a horse. But
there has to be a reality check. It won’t
work for every horse, there is plenty of
potential for complications and it is a
huge commitment for the rest of the
horse’s life that not every owner can,
or wants to, make.”
Nevertheless, the advances in
amputation technique and prosthetic
development now being made offer a
viable alternative and perhaps a new
source of hope to those who would give
just about anything to see a beloved
and severely injured horse romp in the
paddock once again.
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