Fetlock arthrodesis boost survival rates
Lexington, Ky. - It is the most common fatal injury of the racing Thoroughbred - catastrophic injury to the fetlock, involving the distal cannon bone and/or the proximal sesamoid bones of the metacarpo/metatarsophalangeal joint, with a rupture of suspensory apparatus.
Lexington, Ky. — It is the most common fatal injury of the racing Thoroughbred — catastrophic injury to the fetlock, involving the distal cannon bone and/or the proximal sesamoid bones of the metacarpo/metatarsophalangeal joint, with a rupture of suspensory apparatus.
Photo 1: Chelokee, pre-op in the first-aid boot.
There are many traumatic and degenerative versions of fetlock damage, and Chelokee, a 4-year-old colt, suffered one of them during the Alysheba Stakes at Churchill Downs on May 2.
He was taken to Rood & Riddle Equine Hospital, where Larry Bramlage, DVM, MS, Dipl. ACVS, performed a fetlock arthrodesis to save him.
Chelokee's version of the injury involved destruction of all the supporting ligaments to the back of the fetlock and pastern joint.
Teuflesburg, a 2007 Kentucky Derby starter, suffered another version last October — comminuted fractures of both sesamoid bones behind the fetlock joint, destroying his ability to stand on the limb. Bramlage performed successful fetlock arthodesis on that horse as well.
Background of procedure
Bramlage started working on fetlock injury during his residency in the mid-1970s, just after the death of Triple Tiara winner Ruffian. "There are several different versions of the injury, but it's something that we didn't have a solution for at the time, and it was virtually always fatal to a horse," he says.
Photo 2: Chelokee, six weeks post-op.
After studying the mechanics of the fetlock joint and working with surgical approaches that would allow stabilization without added morbidity, in 1978 he handled the first clinical case, a mare that had ruptured the suspensory apparatus by pulling both sesamoids off the long pastern bone.
"Dr. Robert Copeland and Dr. Gary Lavin in Lexington called and asked, 'Have you got anything?'" Bramlage recalls. The mare started to get laminitis in the other foot while undergoing treatments available at the time. Bramlage and colleagues fused the ankle.
Photo 3: This X-ray, taken at presentation, shows Teuflesberg's comminuted sesamoid fractures. The limb is in a splint to prevent collapse of the fetlock.
The procedure itself worked, but wasn't early enough to save the other foot and the mare was lost to laminitis. Fetlock arthrodesis had shown promise earlier, when the team tried it on cadavers and research horses. They had performed it about 10 times, when Bramlage and Dr. Bill Reed were called upon to perform it on Noble Dancer after his injury at Belmont Park. The famous runner went on to a stallion career of 20-plus years before dying of infirmities at 25 or 26.
After several more successful surgeries, the procedure became known as a viable solution for fetlock injuries and for other joint issues such as degenerative arthritis (DA).
Photo 4: These final films were taken after the arthrodesis had healed at 10 weeks post surgery, just before Tueflesberg started unrestricted paddock exercise.
"We use it in other types of horses, other than racetrack-injured Thoroughbreds," says Bob Schneider, DVM, MS, Dipl. ACVS, a professor at Washington State University's College of Veterinary Medicine. "In fact, (one of) the last two horses I've done it on ... was an Arabian performance horse, a mare with degenerative arthritis. She lost the cartilage, and had bone-on-bone contact in the joint. So we fused her, to save her as a broodmare. I also fused a rescue horse with a bad degenerative rear fetlock. It was in chronic, unrelenting pain from a degenerative fetlock joint and now, after the procedure, is much more comfortable."
"Arthrodesis is an opportunity to circumvent many of the really bad problems of the fetlock joint, and the real benefit of it is (that) the horses are almost immediately pain-free," Bramlage explains. As soon as the pain of the incision and the surgical approach has passed, they begin bearing weight on the leg.
As aftercare improves, some horses do light exercise as soon as a month after surgery and are in the field as soon as three months.
"These horses post-surgery are very quickly pain-free," agrees Dean Richardson, Charles W. Raker professor of equine surgery and chief of large-animal surgery at the University of Pennsylvania School of Veterinary Medicine's New Bolton Center.
What Richardson usually tells his residents is that, right after the fusion, horses normally are sore for 24 to 48 hours. "But when a surgery is successful, most of those horses are sound within two days, comfortable, standing squarely," Richardson says.
"Contralateral laminitis probably is one of the most important problems that we have, as with any major orthopedic procedure. If they bear too much weight on the opposite limb, there is a chance of laminitis," he adds.
On the other hand, with fetlock fusions after the typical racetrack breakdown, if the surgery goes well and without complications, many horses become comfortable so quickly that laminitis in the opposite foot is not a major issue.
The goal is making sure the surgery allows the horse to stand squarely on the injured leg relatively quickly after the fusion.
"Even though laminitis is a big complication, the bigger complications usually are local infection, breakdown of the pastern region and other problems that aren't exactly associated with the surgical fusion," Richardson suggests. "If you have those problems, the horse doesn't become comfortable and laminitis in the opposite foot is more of a risk."
Tension band placement
The key to the procedure was the insertion of the tension band in the back of the joint. "You can't put the plate in the back of the joint where you would mechanically like to put it, because all of the injury that occurred there," Bramlage says. "The approach is difficult, and there's no real good place to attach it. And when the horse has a suspensory apparatus rupture, you're worried about blood supply. So if you do the surgery in the back of the joint, you add to that problem," he explains. "So we put the implant in the front and then go actually through the joint to insert a wire or, in the case of DA, you can use the horse's own ligaments by attaching his sesamoids, and that puts a support in the back of the joint, preventing the plate in front from cycling," Bramlage says.
"It's the same mechanical concept as extending a crane, where you see them put the joint at the end and another boom on the end of the crane and they run the cable up over this prop," Bramlage explains. "That's the exact analogy, mechanically, that we use to give stability in the back of the joint. It results in such a stable fixation that it's really pain-free."
A horse will have some pain to overcome from the original injury and some from the incision, but instead of taking weeks to get it back on the leg comfortably, it can be a matter of days, which protects the other foot from laminitis. "That's really what you need to have a chance at a successful recovery," says Bramlage.
There is no question that stabilizing the pastern, incorporating the pastern joint treatment into the arthrodesis of the fetlock joint, is part of managing certain types of traumatic breakdowns of the fetlock region. But it doesn't have to be done in every instance. "There are different ways of approaching that problem, including Bramlage's use of a cable technique to the back of the pastern joint," explains Richardson. "We've tried different techniques. It is an important point that the ones that need their pastern fused are a subset of the majority of fetlock breakdowns. The majority of them don't need that."
"I pretty much do it the way Bramlage does it," says Schneider. "I haven't really modified anything."
Perhaps the biggest change for the procedure is a new plate, a locking compression plate, where the screws not only go into the bone, but the head of the screw enters the plate. Because of that feature, screw heads and screw fatigue life is much longer.
"I do think the implant, the technique ... has continued to evolve, from a point where it was fairly high-risk to a more routine orthopedic surgery," Schneider suggests. "And it still has a higher rate of complication than some of the things that are done. But on the other hand, when it works well, it is definitely something that saves horses' lives."
Value of the procedure
Bramlage has taught the procedure in an internal-fixation course at Columbus, Ohio, every other year for 25 years, with the help of AO North America, sponsor of the laboratories. "I think most all of the surgeons in the country probably learned (it) in the AO course," says Bramlage.
"In the first group of horses we presented, the success rate of the primary treatment approached 70 percent," he says, "and for certain kinds of injuries, such as degenerative arthritis, it's as high as 80 percent. Our biggest problem is still laminitis. The ones we have difficulty with are those with the other foot already failing, although it (the procedure) will actually rescue some of those horses."
"What is still not completely understood by a lot of people in the industry is how successful the surgery can be in terms of taking a horse that has a painful, severely arthritic fetlock joint and making it very comfortable and capable of living essentially a normal life in terms of being breeding-sound," says Richardson. "It's really not that well understood out there how normal these horses can be after the fetlock is fused. It's a very important surgery in terms of being able to save horses' lives with major fetlock injuries."
"Regarding Chelokee, he's to the point now that he has his cast off and has been totally without external fixation for a month," Bramlage says. "He's starting his walking. His incisions are well-healed. So far his other foot shows no problem."
Chelokee is expected to be out of the hospital in a few weeks and ready for stud, retiring from racing with five career victories and earnings of $384,125.