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BUCKED SHINS STIMULATION
For bucked shins, stimulation of the periosteum increases the rate of remodeling of the cortex of the cannon bone by laying down new bone on its front surface. Eventually, the bone will gain strength and rigidity to prevent overflexion. One method of stimulation is shin scraping, which William Russell, D.V.M., a senior partner in Ocala’s Peterson & Smith Equine Hospital, uses to prevent shins from bucking. “It scars the periosteum down to the bone and irritates the bone enough to lay down more bone,” said Russell, whose focus is training and racehorse medicine. “So you are basically putting the horse through a stress cycle like you would if you were doing a breeze or two, and you’re strengthening the cannon bone that way.” Shin scraping must be done before any heat or swelling occurs, Russell said, or you have missed the window of opportunity. “A lot of people do it very early, usually right after the horse is broke,” he said. “Once the horse is broke and going to the track, they’ll scrape the shins and give the horse a couple of weeks off and then progress on with its training. It’s not 100% effective, but it’s significantly effective to prevent bucked shins.” A variation of shin scraping, the needle-scratch procedure, is a treatment—rather than a preventive—for bucked shins that has achieved good success. To perform the needle scratch procedure, the veterinarian clips and anesthetizes the shins. Then he sticks a 14gauge needle straight to the bone and scratches the periosteum. He does this about 100 times per shin in a pinfiring pattern. The veterinarian then applies an iodine (biozide) salve to the shins and covers them with gauze. The needle scratch procedure is unique in that the horse misses only five to seven days training, hardly enough time to lose significant conditioning, and aftercare is minimal because there is little soft tissue trauma. During the first five to seven days, the horse’s legs are rubbed with alcohol and bandaged. Exercise is limited to hand walking. Light training on the racetrack can resume with a gradual increase in intensity over the next three weeks. One month after the procedure, the horse is back up to speed. Continuing in training after bone stimulation is essential to encourage bone remodeling. Laying the horse off after the procedure defeats the purpose. CONSERVATIVE TREATMENT
Unless bucked shins causes a saucer fracture of the cannon bone, most veterinarians take a conservative approach to treatment. “I don’t do anything special, really,” said John Peloso, D.V.M., M.S., a board-certified surgeon and partner in the Equine Medical Center of Ocala. “We give the horse a lit56 THE FLORIDA HORSE • SEPTEMBER 2010
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tle Bute [phenylbutazone, an anti-inflammatory], tell the trainer not to go fast, but just to continue to gallop him for 30 days until the pain goes away. We feel like the training has gotten out of step with the bone’s ability to lay down more dense bone. We feel that if we slow down the training so that the remodeling process can catch up to the training, it [bucked shins] usually looks after itself.” Some owners and trainers might want to see the veterinarian doing more for the horse, but Peloso said intense treatment really is not necessary. “In the short term, when the horse is sore on day one, two, or three, I’m happy for him to be in a poultice, but the most important thing is the anti-inflammatory,” Peloso said. “I know that people push for us to do more, but I don’t think any more is necessary.” Peloso said serious cases of bucked shins that are associated with saucer fractures are rare. “If you had 100 horses that bucked their shins, I’d say saucer-fracture formation would be less than 5%, even if you continue to train them,” he said. Peloso said the most conservative approach is to take the horse out of training, but he believes that is the wrong approach. “We just slow down the training,” he said. “Keep galloping for 30 days, no speed work, and a little bit of Bute if they need it, and try again.” SHOCK-WAVE THERAPY
COURTESY EQUINE MEDICAL CENTER OF OCALA/DR. JOHN PELOSO
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One modern approach to bucked shins is shock-wave therapy. A very rapid pulse of pressure is focused on the shins to stimulate formation of new bone. Because shockwave therapy has an analgesic effect, it eases pain while encouraging healing. “If we treat them at the first sign of bucked shins, we might be able to prevent them from ever becoming sore,” said Scott McClure, D.V.M., Ph.D., head of equine surgery at Iowa State University who pioneered the use of shock-wave therapy in horses. “We lose too much time with a disease that is so well identified and well understood as bucked shins. Why are we still dealing with this problem in essentially every young horse that comes through training? With shockwave therapy, we wouldn’t have to lay all these horses off while they cripple along getting over bucked shins. “I think it is ideal for saucer fractures,” he commented. “It promotes healing across the fracture. The other way of treating saucer fractures is by drilling and screwing them, and there is a risk of cracking the cannon bone. With the shock-wave system, we‘re not worried about that.” With shock-wave therapy, McClure estimated layoff time still would be from two weeks for uncomplicated bucked shins to six weeks for more serious cases involving saucer fractures. ■
These scintigraphic images were collected using a gamma camera during a “bone scan.” The image at top identifies a normal cannon bone (shin), and the lower image identifies a horse with “bucked shins.” At the tip of the black arrow, there is a focal, moderate to intense increased radiopharmaceutical uptake, the trademark of “bucked shins.”