Updated on 09/18/2011 1:04AM

After surgery, concern is infection

Sabina Louise Pierce/Univ. of Pennsylvania
This photo of an X-ray of Barbaro's right hind leg reveals the extent of his injuries. Surgeons used 23 screws and a locking compression plate to repair the damage that the Derby winner suffered during the Preakness Stakes last Saturday.

LEXINGTON, Ky. - Barbaro has survived the major surgery to repair his shattered right hind leg, and the sight of him contentedly eating hay in his hospital stall has been a comfort to his fans. But he still has a long way to go, and his life is not yet out of danger, veterinarians said.

Repairing Barbaro's fractures required surgeon Dr. Dean Richardson to insert 23 screws, usually made of titanium or stainless steel, and attach a locking compression plate to the bone.

Now Barbaro's veterinary team will focus on preventing laminitis, a stress-related hoof disease, and any infection around the surgical site and inside the leg. Either condition could prove fatal.

Horses often develop laminitis by shifting weight from an injured leg onto the opposite leg, which can then overload the healthy leg and cause laminitis, or founder, from the added stress. The risk of infection can be increased in a lengthy, complicated surgery of the kind Barbaro underwent Sunday. Bruised skin from the initial injury also can contribute to infection. Bone and joint infections are notoriously difficult to clean out.

"Any time you make an incision, you have the risk of infection, especially using as many implants as that," said Dr. Dwayne Rodgerson, a surgeon at Hagyard Equine Medical Institute in Lexington. "The horse will be treated aggressively with systemic antibiotics, and he's presently in a cast. Wounds typically heal a little better in casts."

Barbaro's injuries were especially complex. He sustained three basic fractures: a shattered long pastern bone, a condylar fracture of the cannon bone, and a sesamoid fracture. The surgeon's primary goal in the face of such catastrophic injuries is to stabilize the fetlock joint, and as quickly as possible.

"The biggest thing is getting the thing put together," said Dr. C. Wayne McIlwraith of Colorado State University's Equine Orthopedic Research Center. "Ideally, you want to be as quick as possible. The less you have it open, the less chance you've got of other complications. But obviously this was a very, very difficult fracture."

"You're trying to get a stable column of bone from the top of the cannon bone right down to the foot," Rodgerson said. "Your goal is to get that stable column so that the horse can stand up and balance himself. Unlike a human being given six to eight weeks off, you can't do that with a horse."

A major factor in the surgery, Rodgerson said, is how much bone there is to work with.

"In this particular case, they had very little bone to work with in the pastern," he said.

The locking compression plate, a relatively new device, is especially important to Barbaro's recovery.

"The plate itself hasn't been used in the equine-surgery world very much," Rodgerson said. "The University of Pennsylvania is one of the first to do the research on that plate and show the advantages over the traditional bone plates we have. This plate has the advantage of being used when you don't have much bone or good bone, and, in this case, where the bone was broken into so many pieces, it allows for more stable fixation than you'd get with a traditional bone plate."

But the risk remains that the stabilization devices will not hold in a case where the bone has been shattered into, according to Barbaro's surgeon Dr. Richardson, "20-plus pieces."

"That's a concern: Will the fixation break down over time?" said Rodgerson. "So they'll follow him along and probably X-ray him quite frequently over the next couple of months."

If the support devices allow Barbaro to keep weight on all four feet, they will also aid in staving off laminitis.

"It's better that it's a hind leg than a front leg," said McIlwraith, adding that horses carry 65 percent of their weight on their front legs. "But you still have to worry about laminitis. You like for the horse to bear weight on the injured leg as soon as he can. That's always our biggest worry, and it can happen very quickly."

Another secondary concern is stress-related systemic illness such as colitis.

"He'll be monitored carefully for that to make sure his fluids are in balance," said McIlwraith.

If Barbaro survives the ordeal, the good news is that there should be few long-term effects on breeding soundness or arthritis, though he may always have what veterinarians term "a gait deficit."

"If his fracture heals and he's got a fused hind fetlock and he doesn't get bad laminitis in the other foot, he'll be okay for breeding," said McIlwraith. "Obviously, there are a couple of ifs there."