Feb 232018

By Patty Wilber

Over the last month I had begun to notice a slight decrease in stride length and impulsion in Indy’s trot, but I kept trying to tell myself I was imagining it because she was going square (evenly on all four legs, no classical lameness), and we were just getting back into training after her bone chip surgery last July.

Photo of Indy by Janet

But last Wednesday, when I went to work cows, Indy declined to pick up her right lead readily and when she did, she kind of popped her head up to get into it instead of rounding up and driving from behind.   Ed Krauss also noticed that she was short striding with her left hind when I did get the lope. I could not feel that from on her, but I could see it in the round pen and when she would stop and roll back, we both commented that she didn’t want to drive off her left hind.

Talk about depressing. First because she was not right, and second because I ignored two clues–the shortened trot and the reluctance to lope off on the one lead.

So, I called Dr. Lane Dixon and he came out on Friday.  He thought she looked fine at the walk and trot, too, but also saw the short stride at the lope.  When he performed the flexion test, it took her two steps to go sound on the right hind but five steps on the left.

He X-rayed her hock and found that it looked really clean.  Whew!

He took a sample of her joint fluid and it was normal in color and consistency. Also good!

Next we decided to “inject her”.  It is common to hear horse owners say, “We had her injected.” This means stuff is injected into the joint.

So, a little on joints.  (You can click on the pictures below and get to their sites of origin, by the way.) Joints are where two bones come together or “articulate”.  Highly movable joints are called synovial or diarthrotic joints and all have a fibrous joint capsule, a synovial membrane that secretes slippery lubricating synovial fluid into the joint cavity, and cartilage on the ends of the bones to help protect them from each other when the joint is in motion. (In bone chip formation some of the cartilage inappropriately ossifies, forming the “chip”–even though they look more like beans–that protrudes into the joint cavity and can cause damage as the joint moves.)

A combination of an antibiotic (amikacin), a steroid (triamcinolone), and hyaluronic acid (a component of normal joint fluid) was injected through the fibrous capsule, past the synovial membrane and into the joint cavity.  The antibiotic was to stave off any infection that might occur as a result of penetrating the joint, the steroid is to reduce inflammation, and the HA is also supposed to have some anti-inflammatory properties, although, apparently, studies on it are conflicting.  According to this article, the effects of the steroid will persist for about three months. That article also had some depressing statistics on the lack of efficacy of joint injections that hopefully do not apply in our case.

Clearly, a horse’s hock does not look like the simplified synovial joint shown above.  It is a lot more complicated and is homologous to our ankle!

So, where the heck did the injection go? Well, apparently, there are four points of articulation in the hock that are common sites for injection.  In Indy’s case, it was the joint where the surgery occurred, the tibiotarsal joint.  

Of the four joints in the hock shown above, the top two are the most mobile.  The article that supplied the graphic above is a discussion on hock fusion, in case anyone is interested.  The top two joints actually communicate with each other, so the injection Indy got will decrease inflammation and relieve discomfort in both of those areas. These injections can be given every 6 to 12 months, but hopefully, we are dealing with a short-lived and not a chronic issue and will not need to do more.

In addition to the joint injection, she got an intramuscular shot of Ichon, the generic (and cheaper) version of Adequan. She will get 5cc’s every four days and then will get 5cc’s once a month.

Ichon is  polysulfated glycosaminoglycan (PSGAG) and it inhibits many of the enzymes (molecules that catalzye reactions) that degrade cartilage and hyaluronic acid in the joint according to Wikipedia. The PSGAG is easily absorbed and will reach the cartilage within two hours of administration. The idea is that it will help maintain the partially damaged (due to the bone chip issue) cartilage in her joint.

Lastly, I ordered an oral joint supplement called Cetyl M.  I chose this one because I knew the name of it and because it is one of the less expensive oral supplements.  This is the blurb on it:

“Advanced Cetyl M Joint Action Formula for horses is a powerful 5-way joint action supplement that attacks the problem at its source by regulating the immune system response to joint stress. Cetyl M is a potent, highly palatable granule for greater joint support with 5,500 mg of cetyl myristoleate, 3,000 mg of glucosamine-HCL, 3,000 mg of MSM, 1,000 mg of vitamin C, and more!”

Ok, so I did not do my due diligence on this product before I spent my money.  While it does say it is palatable, there is no information on absorbtion or efficacy of the various components.  In the course of looking up things for this blog, I did a bit of research and found a summary of studies that cited a paper that found cetyl myristoleate can aid in decreased joint pain in humans. They cited two papers showing MSM was even more beneficial than cetyl m.

Last Sunday, two days after the injection, we went to work cows.  We avoided loping because I was paranoid, but I noticed Indy wanted to trot out and her trot felt stronger and more driving. No cows this weekend as the truck is in the shop.

I seem to spend a lot of time crossing my fingers and hoping this horse pulls through her various bang ups.

Why stop now? Fingers crossed!