http://stablemanagement.com/article/the-hock-question
The Hock Question
Nov 06, 2011
Sometimes it starts with a strange sign: Not wanting to perform
a flying lead change, sudden laziness, difficulty engaging the hind
end, not wanting to be tacked up, and any general cranky
behavior in a previously content horse. As the trainer it’s your
job to help your client figure out why the horse has had a sudden
change of heart. Often, after talking to a vet, hock issues are
suspected, and hock injections are a possible solution.
The hock is a very complex joint, and it’s not always easy to
identify it as the source of the problem. Veterinarians need to
take information from as many areas as possible. Dr. Chris
Kawcak DMV, PhD, associate professor at Colorado State
University, believes there are many trainers out there who can
“feel a problem” in the hind end. “Trainers can play a big part in
figuring out where a horse is sore,” he says. Dr. Steve Kloepfer
DMV of Alpine Equine Services in Longmont, Colo., agrees that
“information from trainers and riders is helpful” in distinguishing
where to look for the source of the problem.
The signs of sore hocks can be as vague as ‘poor performance’ or
‘strange habits under saddle.’ There’s a lot of gray area,” says
Kloepfer. Other times the signs are much more disruptive, such
as bucking, refusing to jump, bolting or charging jumps, which,
Kloepfer adds, “can be a way of running away from the pain.”
Often, sore hocks show up as horses “not performing up to their
potential. When it becomes consistent and impedes the horse’s
ability to work,” says Kawcak, that’s a common sign of hock pain.
Still, there are much more methodical and exhaustive ways of
discerning whether the hock is the culprit. Being thorough is
paramount to a proper diagnosis. Simple flexion tests are not
going to give you enough information.
Dr. Lisa A. Fortier, DVM, PhD, Diplomate ACVS at Cornell
University, strongly recommends a “full lameness exam,”
including flexion tests to help pinpoint the limb or limbs in
question, as well as “blocking the joints with a local anesthetic”
to further pinpoint the problematic joint. Fortier also finds
radiographs and MRIs to be helpful tools in discovering what is
going on inside a joint.
The Culprit: Arthritis
What we are really talking about when confronted with joint pain
is arthritis, which is very common in performance horses. As
Kloepfer puts it, “arthritis is chronic ‘wear and tear’ disease.
Constant work prevents the body from having time to heal the
joint before developing the arthritis.”
The hock joint has to deal with constant friction and strain, or
“long term, low-grade trauma due to exercise,” as Kawcak puts
it. Due to the “low-grade trauma,” the joint becomes irritated
and the joint capsule becomes inflamed. That inflammation is
what causes the pain.
The Injection Solution
Once the hock problem is diagnosed, hock injections are
frequently the solution. When a veterinarian injects horses’
hocks, the injection typically consists of a steroid and HA
(Hyaluronic Acid). HA is naturally found in the synovial fluid
inside the joint capsule, and it plays a role in maintaining the
viscosity of the fluid, which keeps the joint functioning smoothly.
Both the steroid and HA will act as anti-inflammatories; taking
away the inflammation takes away the pain. Both can also “stop
or slow down the cyclical process of arthritis,” Fortier says.
Kloepfer adds, “HA can stimulate the synovial membrane and
synovial fluid, as well as act as a barrier protectant” inside the
joint capsule.
How well do hock injections work? Kawcak holds that “if
diagnosed appropriately, hock injections are very effective, and
the prognosis is excellent.” Kloepfer agrees, saying that “on a
performance horse with suspicion of problematic hocks, if they
have never been injected and are in work, almost 100 percent
benefit,” in one way or another.
In evaluating the success rate of hock injections, it’s important to
look at the horse’s workload. The first set of injections for a
grand prix-level dressage horse will most likely not last as long
as they would for a horse who is asked to perform considerably
less demanding work. A harder-working horse may require more
constant assessment, and possibly more frequent injections,
Kawcak says. The long-term success of hock injections greatly
depends on the expectations placed on the horse.
Hock injections are not a panacea. “There are cases where
injecting the hocks will not work,” Kloepfer says. “The hocks may
only be part of the problem.
They are usually the most critical point of pain in the hind end,
but your average horse is sore in more than one place. Sore, not
necessarily lame.”
He advises that it is important to prepare clients for a “long
haul.” Injecting the hocks may be only the first part of “unmuddying the waters,” as he put it. Kawcak has found in working
on cutting horses that, once the hocks have been treated, the
suspensory tendon would sometimes show up as a secondary
problem.
Fortier and Kawcak both have found that a sore back can occur in
conjunction with sore hocks. Horses typically compensate for
pain in one area by over-using another part of their bodies, and
the back is one of the parts that can become stressed. Kawcak
has had good results using a chiropractor after the hocks have
been injected; this gives the chiropractor a better chance of
being effective in unlocking the back and pelvis.
Kawcak has also observed that jumpers and eventers with sore
hocks will compensate by bearing more weight on their front
ends, which can in turn make front joints sore as well. Where this
is the case, the original lameness exam may not show the frontend lameness, because it was less severe than in the hind end.
However once the hind end is comfortable, front end lameness
can suddenly become visible. Fortunately, fixing the sore hocks
can provide much-needed relief to other parts of the body.
One other caution: Hock injections may make little difference in
rare cases where the bone loss or bone changes are too severe
for any treatment to make a difference.
The Recovery Period
Now that the horse has had the injections, and all is hopeful, how
about going back to work? Fortier recommends active rest, such
as turnout, for a couple days, “to make sure there is no infection
in the injection site, then back to mild exercise such as long and
low stretching work.” She discourages stall rest, as it can create
more stiffness.
Kawcak and Kloepfer agree: both feel it is important to keep the
horse moving. Kawcak advises three days of rest, and for horses
who live in stalls to be “hand walked for at least 15 minutes twice
a day for all three days.” He also says that it is important to
monitor the horse when going back to work, to “start slowly and
see what you get.”
Kloepfer tailors the rest to what was actually injected into the
joint and how much time he feels is adequate to start the healing
process. When he injects HA by itself, his protocol calls for three
days rest. If a short-acting steroid is used with the HA, then he
prefers four days rest. If a long acting steroid is used, the rest
period stretches to two weeks. In this last instance, Kloepfer
encourages riding at the walk after the first three days to keep
the horse moving.
The time it may take to identify and treat a horse with hock pain
may seem tedious, but the payoff is a happy, pain-free horse
that can return to being the working athlete he was born to be.
And that makes it all worthwhile. Kloepfer lays it out very simply
when he says, “there are probably hundreds of thousands of
owners who, had they known all the horse needed was a joint
injection, wouldn’t have gotten rid of the horse.” Don’t be one of
them!
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