Horse Hoof Puncture Wounds
Why hoof punctures are emergencies, and steps you and your veterinarian can take to help your horse
Don’t pull the nail. This is a sentiment I’ll repeat. Because if you take away just one thing from reading this article, it’s that.
Hoof punctures are common and almost always emergencies (and, it seems, rarely does a horse’s sole find a horseshoe nail during normal business hours). Objects penetrating the hoof can introduce bacteria, causing infection within the foot and pastern. “Hoof punctures are one of those ‘It’s no big deal,’ or ‘It’s horribly devastating’ type of injuries,” says Cathy Lombardi, DVM, CVA, of the The Oaks Veterinary Clinic’s Equine and Farm Services, in Smithfield, Virginia.
In this article we’ll explain why you must treat hoof punctures with urgency, steps you can take prior to the veterinarian’s arrival, and what he or she can do for the horse.
What’s at Risk
Anatomically, the hoof is more complicated than meets the eye. While the third phalange, or the coffin bone, occupies most of the hoof capsule, many other structures reside here. “When a foreign object penetrates the hoof capsule, it may come into contact with the coffin bone, deep digital flexor tendon, navicular bone, navicular bursa, or even the coffin joint,” says Allie Catalino, DVM, veterinarian at the Equine Clinic at Oakencroft, in upstate New York. “These structures can be physically disrupted (fractured or torn) by the penetrating object as well as seeded with bacteria.
“The (coffin) bone is only 1.5 centimeters away from the visible external sole,” she continues. “At a similar depth, under the horse’s frog is the attachment of the deep digital flexor tendon to the coffin bone. The small navicular bone sits between the deep digital flexor tendon and the coffin bone at the horse’s heels and is surrounded by the navicular bursa, a synovial structure.”
Joints, bursas, and tendon sheaths are examples of synovial structures. They produce synovial fluid, which helps lubricate and support the neighboring bones and soft tissues. “When inflammation or infection is introduced into a synovial structure, the synovial fluid loses its viscosity and ability to lubricate, which can result in damage to underlying bone or soft tissue,” says Catalino. “With minimal blood supply to a synovial structure, infection is treated with aggressive intervention in the form of flushing surgically, followed by deposition of antibiotics within the structure.”
What To Do
Don’t pull the nail.
After calling your veterinarian, keep your horse in a stall or contained area, if possible. Your horse will likely be able to shift weight off the affected foot for the duration of time it takes for your veterinarian to arrive.
Don’t pull the nail.
Imaging is of the utmost importance in these scenarios. Veterinarians take radiographs of the affected hoof prior to removing the penetrating object. This allows them to visualize exactly what structures the object affects, which will also guide their treatment plan. If the horse needs surgical intervention at a referral hospital, the veterinarian can prep the foot for travel at this time.
Keep resisting the urge to pull the nail.
My trick to stabilize the affected hoof is to place two rolls of Vetrap on either side of the nail over the sole. I will then duct tape the rolls to the sole, allowing the horse to bear weight on them rather than risk pushing the nail further into the foot. This allows you to transport the horse safely, and veterinarians at the referral hospital will know the exact location of the tract in the hoof.
Location, Location, Location
The offending object’s point of entry can tell you a lot about the horse’s prognosis. Obviously, a thorough understanding of hoof anatomy is crucial. Most synovial structures are in the heel, whereas laminae and coffin bone fill most of the area in front of the frog.
“If you have to have a penetrating injury to the hoof, the best-case scenario is the object enters the sole close to the hoof wall and has a fairly straight trajectory,” says Lombardi. “The less deep it penetrates, the better.
“The worst place to see an object such as a nail enter is in the middle third of the frog,” she adds. “The depth that the nail has been driven into the foot determines how serious the problem may be. If it’s fairly short, like a 1-inch roofing tack, it may not be a big deal to treat. If it’s a long nail that penetrates straight in, and I determine it is likely to have penetrated a synovial structure, I’m talking to that owner about immediate referral to a hospital for aggressive care and possibly surgery.”
Your veterinarian’s plan depends on the penetrating object’s location. That’s why it is so, so important to leave the hoof alone until your veterinarian arrives.
“For a simple puncture, with no evidence of synovial involvement, my treatment is very similar to treatment of a hoof abscess,” says Lombardi. “After pulling the nail, I’ll have the owner soak the foot in Epsom salts and water for several days. I have them keep the foot bandaged and the horse in a clean and dry environment.”
Because horses are likely to encounter Clostridium tetani bacteria in their environment, your veterinarian might recommend a tetanus booster if your horse isn’t current on this core vaccination. Bacterial neurotoxins cause a progressive and severe condition, resulting in a neurologic gait, third eyelid protrusion, inability to chew, and hyperexcitability to stimuli. Advanced cases can result in respiratory distress, seizures, and death. It’s always easier to prevent tetanus than treat it.
Your veterinarian might prescribe non-steroidal anti-inflammatory drugs, such as phenylbutazone and flunixin meglumine, to alleviate the horse’s pain. These drugs work to reduce inflammation in the hoof caused by the penetrating wound and are very effective at making these horses more comfortable.
Depending on the case, your vet might also administer antibiotics either systemically or via regional limb perfusion.
“For cases where no synovial structures are involved, those horses recover quickly and fully,” says Lombardi. However, cases involving synovial structures need aggressive and urgent care, oftentimes at a specialty clinic. Early referral can give these horses the best prognoses.
Your horse stepped a nail, you didn’t pull it, and your veterinarian was able to come out right away. Radiographs revealed the nail penetrated the navicular bursa, and your veterinarian suggested referral. D. Michael Davis, DVM, MS, owner of New England Equine Medical and Surgical Center, in Dover, New Hampshire, explains what happens with these cases at a referral hospital.
“The goals are to explore the puncture wound or draining tract to its depth, most often creating an opening to allow better drainage,” says Davis. “If it’s known that a synovial structure is involved in the puncture or the tract leads to a synovial structure, then a plan should be made to lavage that space as well as open the puncture/draining tract.”
The purpose of the wound lavage is to clear the tract of bacteria to reduce the risk of infection. “This could be via needle through-and-through lavage or could be via arthroscopy and debridement, all depending on the severity and time to treatment.” Arthroscopy is a surgical procedure that involves lavage and debridement under general anesthesia through small incisions in the skin overlying the affected synovial structure. Vets typically reserve it for very severe puncture wounds.
Challenging cases might benefit from further imaging. Computed tomography, better known as CT scans, can be incredibly useful. “CT is far and away the most helpful to appreciate the 3D perspective of a penetrating wound or tract, as well as the potential ramifications it has on tissue (e.g., bony lysis, or destruction),” says Davis. “It can be extremely beneficial in (planning treatment for) long-term or difficult-to-resolve cases.”
Penetrating puncture wounds are never guarantees. While most can result in a simple subsolar abscess, those involving synovial structures can result in crippling osteoarthritic changes or even death.
Time is not on your side. “There is no doubt that any synovial structure infectious process is an emergency that calls for prompt action to drain, lavage, and debride,” says Davis. “More aggressive techniques (surgical vs. nonsurgical lavage) employed earlier than later can make a difference in overall case progression and prognosis.”
If ever confronted with a penetrating object into your horse’s hoof, it is an emergency. It cannot wait until the next morning. And do not pull the nail. Call your vet immediately for assessment and treatment. Your horse’s soundness—even his life—could very well depend on it.
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