You Can Become A Hind-End Lameness Sleuth

Jerry is a 16.2-hand, substantially built Thoroughbred/Hanoverian cross gelding. He was broken at three but had basically been a pasture ornament since age four until he was placed for sale at age seven. When his new owner tried him, Jerry did a lot of head tossing and was reluctant to pick up a canter. However, she thought he had potential and he passed the vet exam with a comment that his stifles were weak.

The goal for Jerry was dressage, but the plan was to put him into general conditioning work for a year and then evaluate his suitability.

He was worked 30 to 45 minutes/day, six days a week, including walking some hills. While he was described as nicely active in a gait once he got rolling, his transitions were a problem, particularly canter transitions. Over the first two months, he showed improvement but would have episodes every few days where his hind end would slip out from under him for no apparent reason.

One day Jerry came in from turnout with mud all over his hindquarters. He was lame within an hour. The vet on call felt it was hocks, treated him with Adequan and recommended a course of phenylbutazone. Jerry was obviously better the next day but was primarily walked for two weeks. On re-examination by the regular vet it was felt his hocks were OK, but he was back sore.

After another week, the vet then decided Jerry’s back was OK, but his right hock was in question again. A Raytek thermography reading (see June 2001) showed the right hock was sometimes up to 5?° warmer than the left, indicating possible inflammation. The horse continued in regular light work, with topical DMSO and hock-magnet boots.

Over the next few weeks, he became more resistant to canter transitions and started shying, bolting and bucking — all new evasions. In addition, the slipping-out-behind problem became much more consistent and frequent.

At this point, with the approval of her vet, the owner contacted another veterinarian who was also a respected chiropractor. This vet found Jerry “sore all over” and suspected some malalignments in the sacral area. She suggested a neurological exam with a work up for EPM and cervical instability/wobbler was in order. Both possibilities were horrible, and the new owner was devastated.

Front vs. Hind
Similar scenarios to Jerry’s story play out every day, leaving both owners and vets frustrated. Nothing causes more consternation or generates a wider range of possible diagnoses than a hind-end problem.

Lameness in the front limbs is easier. It’s usually at or below the knee, and there’s usually enough swelling/heat to find the area. Plus, flexion tests on the front joints are easy to perform and nerve blocks generally confirm foot problems.

In addition, a horse with a front-leg lameness will typically compensate for it, shifting weight to the opposite front leg — and to a lesser degree opposite hind — more quickly. He’ll lighten the load by raising his head and neck higher as that leg prepares to contact the ground, even turning his head and neck toward the opposite side. This creates a visible limp at even moderate pain levels. With lesser degrees of pain, an experienced rider can feel the difference in how the horse lands on one side compared to the other.

Hind-end problems, on the other hand, are more likely to involve the hock or higher. Swelling and heat are more difficult to note in the hind end, and it’s incredibly difficult to do a flexion test for the hock that doesn’t also involve the stifle — not to mention the hip, pelvis and back.

In the front, pain is usually greatest when the sore limb bears the most weight — we look for head bobs and “hopping” up front, knowing to expect it when the sore foot hits the ground. It’s not that simple behind.

Pain in hind-end problems is caused by weight bearing, of course, but it can also be activated when the ligaments stretch and joint surfaces compress, as the horse actively pushes off with the sore leg. The most painful phase may also occur as the joint goes through its range of motion, rather than as it bears weight. This can make the source quite difficult to pinpoint.

If a horse is off in the front because of tendon/suspensory problems, bucked shins or inflamed splints, the diagnosis is usually clear and easily confirmed. Knee problems produce pretty characteristic gait changes, and that diagnosis can be nailed down by a combination of tests and an examination. In a nutshell, it’s unusual for a horse to be treated for a front-end problem without a solid diagnosis. Not so for the hind end.

Local nerve blocks or intra-articular anesthesia can be used for hock or stifle diagnostics, but they’re usually not done as they’re technically more difficult and often don’t completely block the joint. Many vets believe that if you’re going to enter a hock or a stifle, you might as well put something therapeutic in there, such as a steroid or hyaluronic acid. While there’s some logic here, it’s really shooting in the dark.

Hock X-rays can be easily done on the farm, but they can be tough to interpret.Degenerative/arthritic changes are common in active horses and don’t necessarily cause pain.

Getting good-quality stifle X-rays on the farm with a big horse is tougher. You may only be able to do a lateral view, which doesn’t really give you complete information.

Radiographs of the pelvis, hips and spine are out of the question without putting the horse on his back under general anesthesia. Other diagnostic options require access to a full-service clinic (see sidebar).

Diagnosis Through Treatment
Given these limitations, it’s not surprising that many horses end up being treated by a “try this and see if it works” approach, just as Jerry was.

Jerry had a chiropractic treatment and was only walked or longed the following week, a week his owner spent with the prospect of EPM hanging over her head. However, a detailed exam and observation on the longe line at all gaits in both directions led the regular vet to conclude it was a stifle problem.

Jerry’s stifles were injected with hyaluronic acid (HA), and he was doing great for the next few days of walking, longeing and the first ride, then he did a little backsliding. At this point, devil’s claw and oral joint nutraceuticals were added. He also started a course of injectable N-acetyl-D-glucosamine. He continued in work obviously improved but still doing some toe scuffing behind.

Jerry had another session with the veterinarian-chiropractor, which the owner felt was pivitol. His back shoes were pulled and the toes rolled, which helped the scuffing, and longer pasture time could be added to his schedule. Jerry has returned to work and is gaining condition steadily.

What Should You Do’
Jerry’s story isn’t a treatment blueprint for every horse with a hind-end problem, but there are lessons to be learned. Jerry’s owner was a determined, experienced horsewoman who acted as an educated liaison between several qualified professionals. She correctly started with her own vet and, with his approval, involved a veterinarian-chiropractor and her farrier in her horse’s diagnosis and therapy.

She wisely realized rehab was as important as any drug and was willing to give the horse a chance to work through the ordeal with sane, regular work, generous turnout time and an approach to trimming/shoeing that helped the horse move comfortably.

Jerry probably was sore in more than one location, which complicated the picture and final diagnosis. However, by maximizing her resources, Jerry’s owner foun d the right combination of therapies and put the horse on the road to recovery.

Also With This Article
Click here to view ”Hind-End Smarts.”
Click here to view ”Diagnostic Options.”
Click here to view ”Is It Neurological’”