Monday, April 07, 2008

Quarter Crack Repair: Why Hoof-Impaired Athletes Like "Big Brown" Need Expert Care

Click on the "play" button to see a closeup video of a quarter crack and the initial stages of the repair process typically undertaken on a horse that needs to stay in training. This video is by Ian McKinlay of New Jersey, the quarter crack expert consulted for Big Brown's hoof problem. The horse in this video is NOT Big Brown and this horse's problem is not identical to Big Brown's!

A freakishly fast young Thoroughbred named "Big Brown" won the Florida Derby last week in spite of having "quarter cracks", or wall separations, in both front feet. The "cracks" were immobilized and he was wearing specially-adapted glue-on shoes (more on them later). From the email queries coming in, it seems that a lot of people are not really sure what a quarter crack is and what it means to a horse...especially a horse who hopes to win the Kentucky Derby three weeks from now.

First of all, please understand that a quarter crack is a specific injury to a foot, but that, at the racetrack, people often refer to multiple problems as quarter cracks. There are also bar fractures, heel cracks, subsolar abscesses that affect the wall, and other problems that are repaired with patches or glues and, in backstretch lingo, are called "quarter cracks".

This article refers only to the explicit condition of an actual crack in the inside quarter of the hoof wall. It is a common problem for racing Standardbreds and Thoroughbreds.

A quarter crack is literally a fracture of the hoof wall through the area of the hoof known as "the quarter", a point where, more or less, the geography of the hoof wall completes its arc around the toe, and the heel region begins. Sometimes you can see where angles of the hoof tubules change between the heel area and the radial part of the hoof. Some farriers refer to toe quarter, "the" quarter, and heel quarter as regions of the hoof wall.

Obviously, the regions of the hoof are much more delineated on a larger foot,and much more visible on a white foot.

Horses usually get quarter cracks in the medial (inside) hoof wall, as opposed to the outside wall. This is generally believed to be because of the shear forces of the horse's weight from above that is either abnormally high on the inside hoof wall, or because the foot is misshapen or weakened (known as "medial-lateral imbalance"). Conformation, improper shoeing, neglect and poor quality hoof walls are some of the causes of quarter cracks but experts say that they are often surprised when relatively normal hooves develop quarter cracks, possibly as a result of training or running over hard ground or changing gait so that suddenly more of the horse's weight loads the inside wall.

In simplest terms, a quarter crack is like a split fingernail that goes right up through the cuticle. Ouch! Now, imagine standing and bearing weight on that cracked nail. And then imagine running on it. And Big Brown has two of these cracks, although they are both in the healing process.

This, of course, is a vast over-simplification of one of the most complex disorders that can affect a hoof, and is meant only as an explanation for people outside the hoofcare field who are asking for more information about what quarter cracks are.

To answer one question: No! Cracks are not like musical notes, there are no half or eighth hoof cracks, that I know about, anyway! (Great question!)

Dr. David Hood of the Hoof Project, in his great little book "Building the Equine Hoof", offers a simple explanation: "Deep cracks occur when loads placed on the wall are greater than the structural strength of the wall. Inadequate blood flow, lack of balanced nutrition, or improper cornification can lead to a weaker wall prone to cracking."

The goal of crack "repair" is not to heal the crack but to immobilize it so that new growth can begin. A very serious crack will damage the top of the wall at the hairline, called "the coronet" (crown of the hoof). This is the area where new growth starts, and scar tissue in the coronet will prevent normal growth. Sometimes the wall that grows down from the cracked hoof is a different consistency and the zone is always in danger of a repeat fracture.

You'll notice on the video how soft the hoof wall is on this Thoroughbred, particularly in the detached heel area.

There's no doubt that these young Thoroughbreds have thin walls and that they are prone to these cracks. It's also pretty amazing how they heal.

As nasty as a quarter crack looks, an expert patch job can keep a horse running. And winning. One of the most famous crack repairs was on Kentucky Derby winner Ferdinand back in 1987 when he ran by Alysheba to win the Breeders Cup. Ferdinand's crack was patched by California horseshoer Buzz Fermin. The great Standardbred Nihilator was known to have raced wearing "mushroom" shoes, which remove pressure from the heel area.

NOTE: This is not a "how-to" video. The hoof walls on these horses are incredibly thin and the skill that it takes to properly drill through the wall without damaging live tissue is critical as is the exact amount of pressure used when lacing. Ian has been doing this for as long as I can remember and his skill is remarkable. Don't try this at home.

Click here to read about an interview with Big Brown's trainer, Richard Dutrow, about the colt's hoof problems, shoes, and consulting farriers.

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