Advances in technology and experience have greatly improved orthopedic surgery techniques for equine fracture repair, said Dr. Dean W. Richardson, the Charles W. Raker Professor of Equine Surgery and Chief of Large Animal Surgery at Penn Vet’s New Bolton Center.
Both newer surgical hardware and major advances in imaging make it possible to successfully repair complex injuries that would have never even been attempted years ago.
Richardson discussed the latest in surgical techniques during the May First Tuesday Lecture, a monthly series offered free to the public on equine topics at New Bolton Center.
“Fracture repair involves getting the perfect balance of mechanics and biology,” Richardson said.
Richardson is one of the world’s foremost experts in equine orthopedic surgery. He received his DVM from The Ohio State University in 1979, completed a rotating internship and residency in large animal medicine and surgery at Penn Vet, and received postgraduate training in the Division of Rheumatology at Thomas Jefferson University.
Surgery is his clinical specialty and his research areas are large animal surgery, equine emergency surgery, and equine lower limb injury. He is board-certified by the American College of Veterinary Surgeons.
When repairing broken legs in a horse, it is important to do so quickly, to prevent the horse from developing laminitis, a very painful condition in which the coffin bone becomes detached from the hoof.
“We need to fix the fracture so well that the horse can stand up following the surgery and walk immediately,” he said. “We try to make fractures so stable, so quickly, that they don’t have time to develop laminitis.”
Improved metal fixation devices help make the repairs stable. Richardson described a “locking plate,” which is a major advance in the devices to repair equine leg bones. The head of the screw that attaches the bone tightens securely into the plate as well as the bone.
“These devices provide greater stability and far more options for placement, including techniques that involve smaller incisions,” he said.
Critically important is to have a fully equipped and strategically designed orthopedic surgical suite, like the one at New Bolton Center. “In order to do the sophisticated techniques needed to successfully repair complex injuries, the operating room and all of its contents need to be state-of-the-art,” he said.
A great advance is the use of computed tomography (CT) scans during orthopedic surgery to completely characterize the break. A CT scan combines a series of X-ray images taken from different angles, and using computer processing, creates cross-section images of the bones, blood vessels, and soft tissues. The surgeon can easily comprehend the complete three-dimensional configuration of the fracture.
Many repairs are now done with minimally invasive surgery, using a combination of the CT, intraoperative fluoroscopy (real-time X-ray), and arthroscopy. The entire procedure is performed through tiny incisions instead of surgically opening up the leg.
“I can’t see it directly, but I know where everything is through the CT scan,” Richardson said. “The surgeon must go through a precise series of steps to properly use a screw in bone. It isn’t quite like hanging a picture on the wall!”
Richardson is constantly striving to improve techniques.
“In our equine athletes, we need to seek perfection in the repair. I have to get the joint surfaces aligned perfectly or the horse will get arthritis,” he explained. “If it is a strong enough screw and in the right place, it will work.”
Repairs can even be made to fractures within the hoof, on tiny, but very important, bones. “It’s like putting a screw through the middle of a straw,” he said. “This is a very difficult surgery.”
During the lecture, Richardson gave examples of several challenging surgeries that were successful, including Animal Kingdom, a champion Thoroughbred who, in 2011, won in the Kentucky Derby and came in second in the Preakness, and then fractured his hock in a bad stumble during the Belmont. “This is a particularly difficult fracture,” Richardson said, showing the radiographs of the horse’s hock.
“This may look simple, but to put screws into a horse of this much value, under this much pressure is difficult,” he said. “If I make an error of just 2 or 3 millimeters in the wrong direction…he will become a breeding stallion…he’s not going to race again.”
The surgery performed by Richardson was successful, and Animal Kingdom went on to win the $10 million Dubai World Cup the following year. “Having this kind of technology makes this surgery so much easier,” Richardson said, describing the intraoperative CT scan.
“It’s really intimidating to perform this kind of surgery without this kind of technology, but fortunately we have it and know how to use it.”