When Quarter Horse stallion Triple Vodka developed a septic coffin joint in 2021, Texas-based breeding farm Zerlotti Genetics had to terminate the multiple stakes winner's breeding season early. Despite top-notch care, the debilitating issue worsened over the course of the year, and eventually became so serious that only two options remained.
Either Triple Vodka would have to be euthanized, or he could be sent to Wyoming's Yellowstone Equine Hospital to meet Dr. Ted Vlahos.
Vlahos has become an industry pioneer in equine limb amputation and prosthetics, completing over 100 cases across four continents. Amputation is a last-ditch effort to preserve a horse's life, Vlahos explained, and he only performs the procedure under strict circumstances.
“Our premise is that we much prefer that a horse have four legs than three, but in cases where we can't save the leg, we are able to save the horse,” Vlahos said. “We deal with the most severely injured horses in the world. We get the worst of the worst, so we're eliminating that source of pain and disease.
“The procedure is well-tolerated by the horse and they can do very well, but it's not for everyone. We thoroughly interview clients to be sure they're fully committed, and that their horses are good candidates for it.”
Another consideration is whether laminitis has already progressed in the horse's supporting limb. Initially, Vlahos and his team avoided cases with any signs of support limb laminitis, but after 22 years of performing the procedure they have documented mild cases resolving after removal of the damaged limb and addition of a prosthetic.
Triple Vodka's easy-going demeanor made him an ideal candidate for the procedure, and the stallion was shipped to Wyoming in the fall of 2021.
Since Triple Vodka's issue was in the coffin joint within the hoof, his right front leg was amputated below the fetlock.
“In the case of the distal limb, we preserve the sesamoid bones so we have a bulbous end,” Vlahos explained. “We also don't want horses to walk on raw nerve endings on that stump, so we perform a neurectomy removing about three inches of nerve so they can't feel the stump. We also perform a tendon flap procedure, creating a thick pad of tendon at the end of the bone that is then covered with skin.”
Both the neurectomy and the tendon flap procedure are well-described in human medicine, a fact Vlahos certainly appreciates due to his incorporation of the expertise of human trauma surgeons into his practice. Vlahos hired Dr. Dale Larson, a cardiothoracic surgeon with experience in Vietnam, for three years as his assistant to learn about modalities that could be adapted to equine medicine, and he has worked with four other human surgeons to perfect his techniques.
Vlahos looks back to his early schooling at Ohio State as one of the motivating factors in pursuing amputation and prosthetics as an equine specialty.
“I had a pretty famous professor at the time who told us, 'Never be afraid to fail,'” said Vlahos. “That was Dr. Larry Bramlage, and he'd just published his first group of fetlock arthrodesis horses. I took that to heart and was fortunate to be trained by wonderful human surgeons who saw the worst of the worst in Vietnam. They helped me with my desire to advance our profession and help the horse successfully.”
Vlahos' mentor at Washington State, Dr. Barrie Grant, also performed several successful amputations on prominent equines, including a Thoroughbred stallion named Boitron. He had suffered a hauling accident that required a hind limb to be amputated, but his prosthesis allowed him to gallop in his paddock and breed like any other stallion.
Of course, the primary difference between equine and human amputation is that horses are required to be weight-bearing immediately after surgery. To solve this problem, Vlahos places two threaded pins in the distal third of the cannon bone and applies a transfixation cast – this allows the weight to be transferred to the pins instead of to the stump. A metal cup and strap system are utilized to reduce stress at the bone-pin interface when the horse pivots and turns.
The stump is checked for healing two to three weeks after the amputation, and the pins are removed approximately two weeks later to allow full loading of the horse's weight on the stump through the cast. A couple more weeks go by, and the construction of the prosthesis can begin.
It takes multiple fittings and tests to ensure proper alignment of the carbon fiber prosthesis, which opens and closes with straps much like a ski boot to attach to the horse's limb. The base is a titanium post and stainless steel footplate, with borium integrated into the bottom to increase traction.
The horse wears a standard human prosthetic sock, and the sock is initially changed every day, and later every two to three days, depending on the horse's individual needs. The end result is a healthy, happy horse capable of life as a pasture pet or breeding animal.
Triple Vodka returned to Texas with his new prosthesis in January, and was able to be collected approximately a month later.
This Quarter Horse stallion was suffering from a severe infection in his right front foot. Dr. Ted Vlahos was able to save his life by amputating the limb and fitting him for a special prosthesis. Read more here: https://t.co/BA4v0KHd43 pic.twitter.com/ZvzTi0z3Ji
— Paulick Report (@paulickreport) February 10, 2022
Of course, the horse's gait is altered by the procedure. Just like any horse with a fusion of a joint, other joints or parts of the body take up the load.
“Because they've lost range of motion, they appear stiff, mechanically, but they are comfortable,” said Vlahos. “The oldest horse we have right now is 15 years post-op, and he's a very comfortable horse… We expect the horses to not really have any difference in life expectancy.”
While Vlahos has not performed force plate analyses to determine the weight-bearing load on the supporting limb versus the amputated one, he notes that horses are able to pick up their good foot and fully weight bear on the prosthesis for farriery care.
Most equine amputations are performed at the fetlock level or below, but some have been performed at mid-cannon bone, and rarely at the mid-radius (above the knee or hock). In the latter case, the prosthesis immobilizes the joint and requires a strap system similar to that of a high amputation in humans.
“It's been a slow process to get it accepted, but the horses really do so well,” Vlahos said. “I'm pleased that other vets across the world are starting to recognize it as a viable option. When I'm helping other surgeons with the procedure, I routinely hear, 'Why haven't we been doing this before today?'”
In this video courtesy of the Yellowstone Equine Hospital, a hind-limb amputee tries out his new prosthetic for the first time: pic.twitter.com/kySgNFASUt
— Paulick Report (@paulickreport) February 10, 2022
