Moments after he left the starting gate ArchArchArch stumbled and took a bad step. Then the jockey’s saddle slipped forward, leaving him perched on the horse’s neck. Then he got bumped hard.
Somewhere in the melee that is the start of the Kentucky Derby he sustained a condylar fracture to the left front. While the colt went through surgery successfully yesterday, his connections have chosen to retire him.
So, what is a condylar fracture?
A condylar fracture is the most common fracture seen in horse racing and it’s usually reasonably easy to repair. It is a fracture that occurs on the cannon bone at the distal (lower) end.
According to an article on http://www.bloodhorse.com, Broken legs aren’t death, The lateral condylar fracture usually runs from the front to the back of the leg and up the outside. It is repaired using screws and often a horse recovers fully and returns to the track. In one article I read they cite as an example a horse that had three separate condylar fractures over the course of its career, yet continued to race successfully.
Why do condylar fractures occur?
Condylar fractures generally are the end result of cumulative stresses on the bone, that can be triggered by a bad step. Footing also seems to play a role.
In an article on http://www.veterinarynews.com, Condylar fractures, the number one fracture facing racing thoroughbreds, anecdotal data suggests that polytrack (artificial) surfaces may lessen the risk and/or the severity of these injuries because the surface is more consistent. It is worth noting that Churchill Downs is a dirt track, so maybe it’s a possibility that ArchArchArch hit an irregular spot in the base when he got bumped.
“It’s hard to say if condylar fractures are becoming more frequent,” says Carter E. Judy, DVM, Dipl. ACVS, Alamo Pintado Equine Medical Center, Los Olivos, Calif. “At least in California, the type of fractures we’re seeing has changed a bit since the advent of artificial surfaces. We still see condylar fractures but to a much lesser degree, and we’re seeing a different configuration of the fracture type, with the fractures being shorter and thinner than they were previously. In my opinion, they tend not to be as severe as they were before.” Unfortunately, no hard numbers are available to track this potential trend.
According to Larry Bramlage, DVM, MS, Dipl. ACVS, Rood & Riddle Equine Hospital, Lexington, Ky,
“We’ve known for some time that this disease process occurs because of the repetitive trauma to the bottom of the cannon bone that a horse sustains while it’s training.”
He explains that as a horse’s training progresses, its skeleton adapts. Stress produces microfractures. In most cases, these fractures heal themselves as the bone remodels. In fact, the front cannon bones and tibias get bigger and stronger as the bones experience the microfracture/healing cycle. However, the presence of these microfractures also predisposes the horse to more severe fractures if the horse loads a vulnerable area unevenly — say, takes a bad step in a race like ArchArchArch.
“If the tibias get behind in this adaptation, the horses will develop a stress fracture,” Bramlage says. “If the cannon bones of the front legs get behind, the horses will get bucked shins or eventually a stress fracture if they carry on.”
“There are two kinds of vulnerabilities associated with that,” says Bramlage. “One is the original process of making that bone continually stronger in response to training, which can create a condylar fracture. The second vulnerability is the extreme density. If you change the bone away from normal porous or spongy cancellous bone to more dense bone, it becomes brittle, allowing fractures to propagate much more aggressively.
All horses have this process of damage and repair going on at all times. When studies have been done on horses that have a catastrophic fracture in one limb, vets often see small stress fractures in the contralateral limb or damage in the joint.
According to Patty Hogan, VMD, Dipl. ACVS and owner of Hogan Equine at Fair Winds Farm in Cream Ridge, N.J.,
“I found that when I looked in the back of the joint, in about 80 percent of the horses, there was concurrent cartilage erosion or injury of the lateral sesamoid bone—even in the simplest of fractures with no previous history of joint disease,” Hogan says. “So that tells me that there is some undue biomechanical stress on that joint. The cartilage is going to show evidence of that first, and then the bone is going break. It’s a combination of factors that contributes to the bone breaking.
I do think that condylar fractures are not single-event injuries but a stress accumulation-type of injury,” Hogan says. “The more science that we commit to this problem, the more we learn and realize that it’s true. It is rarely the ‘took-a-bad-step’ scenario. These horses have underlying disease that is going on in the bone, in particular the lateral condyle of the cannon bone. This compromised portion of the bone develops a fault line, and then it just breaks.”
As veterinarians have come to understand the causes of condrylar fractures there advice to trainers has evolved.
“In order to get out in front of the fracture outcome, we’ve been looking at scintigraphy and in some cases MRI,” Judy says. MRIs are being performed in some racehorses “that come up sore in their ankles.” Equine veterinarians are seeing tiny nondisplaced cracks right at the articular surface. “These tell us that something may be going on in the ankle, and we recommend backing off on those horses training a lot earlier than we might have in the past,” Judy says. “Those horses have not gone on to fracture those legs after we’ve given them a period of rest.”
For ArchArchArch, his injury means retirement to stud. He’s a horse that will be well taken care of for the rest of his life. But it makes you wonder if soon trainers will be using MRIs and bone scans to check their horses regularly for the presence of stress fractures and can avoid this type of catastrophic injury.