Dealing with a Broken Foot (Coffin Bone Fractures)

When it comes to caring for your horses, you have a lot to think about--diet, training, exercise, and welfare. You don't have to tell us he's worth it (although you think twice on the days he snorts on your white shirt). But there is one part of caring for a horse that every owner dreads and most likely still experiences: Lameness. It can occur for a variety of reasons, including stone bruises, abscesses, improper shoeing...and so on. But a lesser known--and under-diagnosed--reasons for lameness can be one of the most devastating: Coffin bone fractures.

Who's at Risk?

Lance Bassage, VMD, of the University of Illinois College of Veterinary Medicine in Urbana, has seen his share of coffin bone fractures. The good news is that these fractures are not common, but some horses are more susceptible to them than others.

"They're most commonly seen in performance horses," he explains. "Racehorses, both Thoroughbreds and Standardbreds, are probably the most common (types of horses affected), but coffin bone fractures certainly occur in other performance horses that compete in barrel racing, steeplechasing, polo, or eventing, for example. These horses fracture their coffin bones during maximal exertion exercise."

If you're thinking you're out of the woods with your backyard horse you use mostly for trail rides, think again. Even non-performance horses can get coffin bone fractures during what Bassage calls "freak accidents," although it's not as likely to happen in your pleasure mount as it is in a high-performance horse. Freak accidents can be anything from a horse kicking the wall of the stall to one stepping on a rock out in the field. Although these cases are few and far between, Bassage recommends that owners become aware of the possibility, as coffin bone fractures are serious.

What Is a Coffin Bone Fracture?

There are seven different categories of coffin bone fractures. Some are more serious than others, and some are more prominent in particular horses or disciplines than others. But one thing's for certain, when it comes to coffin bone fractures, the ones that fracture into the joints are tough to treat.

Kevin Sherman, DVM, of the Brimfield Large Animal Clinic in Brimfield, Mass., has seen plenty of coffin bone fractures in his career. "We see quite a few racehorses that come through because they have injuries or joint problems," he explains. "The ones with coffin bone fractures involving the coffin joint will often be persistently lame. It's hard to get the cartilage to heal completely. Once there's cartilage damage, it's often permanent. Many times you're going to have perpetual pain."

While the constant pain can often be managed with medication, Sherman is skeptical about the long-term outcome. "With serious joint damage, the joint will never get completely better," he says.

If you're getting the impression that coffin bone fractures are a serious business, you're right. The good news is that these serious cases are few and far between, and there are things that can be done to heal the horse or make him comfortable and useful.

Warning Signs

Again, performance horses are most susceptible, but even foals can have coffin bone fractures. "For owners, the most telling sign is generally an immediate, acute onset of lameness," Bassage says. "As far as external signs, there may not be much more than that. There may not be any swelling, or in some cases, there will be swelling around the coronary band and the digital pulses will be increased."

For fractures that don't involve the joint, there might be no clinical signs. The hoof capsule acts as a cast, keeping the coffin bone stabilized until it can heal.

What's the Treatment?

Your lame horse has been diagnosed with a coffin bone fracture. Now what?

Ask the veterinarian. Your veterinarian will discuss the treatment options with you and what you need to do to ensure their success; follow his/her recommendations.

Have patience. "Healing time in coffin bone fractures, particularly ones that involve the joint, is slow," Bassage explains. "They take anywhere from six to eight months, and sometimes up to a year, depending on the age of the horse and location of the fracture on the bone."

Call the farrier. Most likely, treatment will include a bar shoe--a shoe with a metal piece extending across the width of the shoe at the heel with side clips around the entire foot. If the coffin bone fracture is accompanied by joint problems, a continuous rim shoe appears to be the shoe of choice.

"The idea is to prevent expansion of the hoof wall," says Bassage. Sherman agrees, saying, "The shoe keeps the foot from expanding and contracting, allowing you to keep everything still while it heals." In some cases, if the coffin joint remains painful with a regular shoe even after the fracture is healed, a bar shoe might be needed for the remainder of the horse's life.

Get the stall ready. With specialized shoeing comes stall confinement and/or restricted exercise for the horse. The horse will generally need to be restricted to a stall with minimal movement.

What Happens After Treatment?

Even after treatment, special shoeing, and confinement or limited exercise, there are still problems that can occur. For one, the horse might never fully return to his peak performance. Fewer than half of the horses with joint fractures return to soundness because of arthritis.

"Several factors contribute to the development of arthritis after a coffin bone fracture," Sherman explains. "Cartilage damage resulting in exposed underlying bone is a major factor. Misalignment of healing bone and cartilage is also important."

He says free-floating bits of cartilage and bone also play an important role in the development of permanent joint problems.

"It doesn't have anything to do with age. It has to do with trauma due to the fracture," says Sherman.

What is the Aftermath?

If it sounds like coffin bone fractures are all doom and gloom, they're not--at least not all of them.

Many horses with coffin bone fractures that don't involve the joint recover completely and can return to competition. For other horses, recovery might not be 100%, but the horses can still be used for light work, provided there isn't constant trauma to the foot. For a few horses, the prognosis is poor, and euthanasia might be needed.

"For some of the really bad joint fractures, it's going to be a dead-end deal," Sherman explains. "That's the benefit of getting the radiographs, so you'll know what the future will bring. If the horse isn't going to get better, you need to know so you can deal with it and learn how to live with a lame horse."

Neurectomy

If pain is still present after the coffin bone fracture has healed, a palmar digital neurectomy can decrease the pain from arthritis and in some cases resolve the lameness. If the lameness isn't cured once the fracture is healed, surgically cutting the nerves to the heel might allow the horse to continue performing. A nerve block on each heel nerve should be completed to check if the lameness is alleviated. If the nerve block works, the neurectomy might be an alternative treatment to provide relief from chronic lameness.

The neurectomy is not a cure, and the coffin joint disease can persist. However, with careful management, this procedure can often extend the usefulness and comfort of the horse.

Take-Home Message

Coffin bone fractures, while not common, are serious. They can affect your horse's performance, soundness, and quality of life--not to mention your time and pocketbook. But they can be treated. The best defense is education--and it certainly seems that a little know-how, along with your powers of observation and a trustworthy team of professionals, will help keep your horse sound.


WHAT DO THEY LOOK LIKE? Types of Coffin Bone Fractures

Lance Bassage, VMD, of the College of Veterinary Medicine at the University of Illinois in Urbana, says horse owners should know the types of coffin bone fractures that occur. There are seven, and each involves a different portion of the foot.

Type 1--"This involves the wing of the coffin bone," Bassage explains. "There's a medial and lateral (inside and outside) wing. It does not involve the joint surface."

Type 2--"This is probably the most common," Bassage says. "It involves a larger part of the bone, involving the wing and joint surface."

Type 3--"This is a fracture that virtually splits the bone right down the center," he says.

Type 4--"This involves an area on the coffin bone that is referred to as the extensor process," Bassage notes. "It involves the joint surface on the upper part of the coffin bone, where the extensor tendons attach to the foot."

Type 5--"This is referred to as a fracture that involves the main body (of the coffin bone), called a comminuted fracture," he says. "It refers to multiple fractures in the same bone."

Type 6--"Type 6 does not involve the joint surface," he says. "It involves a crescent-shaped chunk that cracks off of the bone at the toe. It is associated with a disease called pedal osteitis. Other horses in which they occur are those with laminitis when there is rotation of the coffin bone. So these owners are going to know about the lameness long before the fracture occurs."

Type 7--"Specifically occurring in foals, this type involves the solar margin, toward the heel or palmar or plantar process," he says. "They often occur without any signs and without the owner even noticing." These fractures occur during strenuous activity if the foal jumps and lands strangely.

So your horse has a fracture. What could this mean?

Prognosis for Type 1 fractures is good as long as the foot is stabilized properly and the horse is given sufficient time to heal. For the average horse with a Type 2 or 3 fracture, the healing time might be six months to one year. With Type 2 and 3 fractures (that involve the joint), approximately half (or less than half for Type 3) of competitive horses will return to full soundness after healing. Type 5 fracture prognosis is guarded to poor. For Types 4, 6, and 7 fractures, the prognosis is good; horses normally return to soundness.--Katherine Meitner

About the Author

Katherine J. Meitner

Katherine J. Meitner is a free-lance writer located in Milwaukee, Wis., and former associate editor of the American Farriers Journal. Her work has appeared in Western Horseman, Green Magazine, American Farriers Journal, and No-Till Farmer.

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