SI Joint or EPM?

I have a 16yo paint gelding with no history of lameness or injury. Starting in November he seemed stiff on the left side. He started repeatedly switching only his back feet to the wrong lead when cantering clockwise on the lunge line. He also wouldn’t extend his trot when working clockwise on the rail, breaking into a slow lope to take the corner instead of trotting. Everything in the other direction remained fine. He has a slight roach back and is very stiff when left in his stall for a day but otherwise muscles look great. No signs foot problems. He struggles up the barn ramp or small hills, taking smaller strides with his left-front/right-hind legs. He bobs his head more to the right when walking.

The vet X-rayed and diagnosed him with hock arthritis four days ago and injected both hocks but my boy doesn’t seem one bit better today. Based on everything I’ve read, my gut instinct is it’s the SI joint even though he didn’t seem overly bothered during flexions and when pushed in that area of his body. The repeated changing of legs behind on the right lead screams SI pain to me. But then the vet suggested starting with EPM testing instead.

What would you do? Anyone been faced with possible EPM versus SI joint pain before? Should I just start with the chiropractor first (he’s never been adjusted)??

I’ve finally learned what “worried sick” literally feels like. I just want my horse to be comfortable :cry:

I would give the hock injections more time, although you could do a blood test for EPM easily enough in the meantime. If the SI area is sore secondary to the hocks, it will take more than 4 days for things to calm down even if the hocks already are feeling better.

I had one tested for EPM in VA and he showed a 33% likelyhood of an active EMP problem via blood test. It’s not a “yeah, ya have or no ya don’t” test. I was told that a spinal test would be more accurate but I decided that it was cheaper to treat him like he had it vs getting the spinal done. :slight_smile: Same horse has a multitude of other issues, one of which is a looser than normal SI joint on the right side. Good luck, I hope it works out for you.

How long has he been hock sore? If he was overdue for hock injections, it’s likely the SI pain is secondary. It could take a couple weeks to several months to go away completely, depending on the severity. Is he sore to SI palpation?

We’re going through this right now with an eventer in our barn. Cross cantering and four beating to one direction, rests one leg constantly, SI sore to palpation, doesn’t like to extend. He just had his hocks injected a week ago (they were long overdue) and he is not yet 100%. It will likely take a few weeks at the very least for his SI issues to resolve.

4 days is not much time. I’d give it 2 weeks before making a decision on effectiveness. If you aren’t 100% happy, I’d do this:

  1. manual neurological tests
  2. pull blood for EPM test (the good one with percentages)

If those are both negative/low probability, I’d ultrasound the SI - then consider injecting and rehabbing.

Don’t overlook stifle(s), as sometimes problems there can cause that hind lead switching. Maybe take another look at them as well…Good luck on finding out and fixing the issue(s).

Thank you all!!! His symptoms have quickly evolved with a couple more days passing since the injections. The hocks have settled down and my boy is in a much better mood already. His symptoms seem to now be isolated to an even more obvious lack of flexibility in his right back leg and he’s coming up shorter at the walk. We had the stifles x-rayed before the hock injections and they were surprisingly sound. Today he also showed some tenderness in his hips for the first time. We see no obvious signs of EPM – no drooling, balance issues, or numbness. A trusted horse friend so there is no way it’s EPM after looking at him. I’m going to give him a couple more weeks for the injections to become effective and then have him adjusted by the chiropractor for the first time. If it’s still a dead end after a few adjustments, we’ll consider the SI ultrasound. Thank you all so much for your responses! I think (and hope) he just needed hock injections and adjusting.