Condylar fractures—the number one fracture affecting racing Thoroughbreds
Condylar fractures are a large part of practice at Hogan Equine at Fair Winds Farm in Cream Ridge, N.J. Owner Patty Hogan, VMD, Dipl. ACVS, repairs about 50 condylar fractures a year. "It's the most common fracture we see in Thoroughbred racehorses," she says.
A couple of weeks before, Harbinger, winner of the 2010 King George VI and Queen Elizabeth Stakes at Ascot, England, was retired after sustaining a similar condylar fracture. Bone scans also revealed that Kentucky Derby winner Super Saver showed marked activity in all four cannon bones, with a major condylar bruise on the left front fetlock, according to a statement from Larry Bramlage, DVM, MS, Dipl. ACVS, Rood & Riddle Equine Hospital, Lexington, Ky."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.
"I think these fractures will always be part of our racing scene," Nixon says. "The more you train and race these horses, the more they seem to get microfractures that predispose them to more complete and even catastrophic fractures. I wish we could detect microfractures better before they propagate," says Nixon. "The problem with this fracture is that there are areas that have accumulated stress within the fetlock joint and the metacarpal condyles, primarily along the palmar surfaces."
This particular area is predisposed to a subsequent propagating fracture. As a horse is trained more and runs more races, a change occurs in the way the bone structure is oriented. It is not a common fracture in 2-year-olds but is quite common in 3-year-old horses and older. "Bone scan and MRI may help us pick up the early changes that later lead to more complete fracture," Nixon says.
Data from these diagnostic studies are still being accumulated, but the eventual hope is that these noninvasive studies done without general anesthesia will provide enough warning of impending fracture that training can be tapered to allow recovery. "At this stage, we can't say with complete confidence that a fracture is inevitable, but as MRI becomes more available and more precise, it may well be our best tool for limiting complete condylar fracture," Nixon says.