About a year and a half ago I bought a 4 yr old horse who had been lightly started under saddle with the intention to finish and be my show horse. He was an absolute dream of a young horse: dead quiet, willing personality, a little on the lazy side, and naturally balanced/ talented. We had about 6 wonderful months of working with him slowly on the flat. To answer your questions beforehand, he was not being pushed at all: ridden very lightly 3-4 times a week, ground work on the off days, and all day turnout in a large paddock. About 6 months in we started noticing a very slight hitch in his right hind and the trot. I immediately had the vet out who did a few flexions & nerve blocks, which were inconclusive, and he suggested I give him some time off given his age. After three months off just being turned out and non-strenuous groundwork, the hitch had become more pronounced and he could no longer hold a canter behind either direction (under saddle or on the lunge line). To add to it, he had become insanely SPOOKY. Not just your green horse gawkiness but he would go into full panic over nothing. I then brought him up to a well respected University which did a full 8 hrs of lameness exams, x rays, ultrasounds and flexions with no result. I took him home and started him on a two week cycle of bute and a loading dose of pentosan (per the vets suggestion) which had no impact on the mystery lameness. Iāve brought him to two more vets, had his teeth done, consulted with a nutritionist, had him chiroād, acupuncture, neuro exam (which was slightly suggestive). He has also tested negative for Lyme, EPM, Vitamin E deficiency, and vision problems. Heās an absolute sweetheart and you can tell something is just wrong with him but I have hit my limit both emotionally and financially and I do not know what else to do. Any suggestions would be helpful.
Since I had something very similar with my guy, did you x-ray his back? Aries had kissing spines, and his only symptom was a general weakness in the back in, and that hitch (his was on the left). Drugs did nothing, his back chiroād just fine. Finally had to break down and do a bone scan to find it.
Something to consider.
did you xray his neck? could be spinal cord impingement in the neck
Oh no, that sounds heartbreaking.
Youāve clearly done your homework on this horse and you still have no concrete diagnosis. Iām sure lots of people will chime in with possibilities, but it sounds like youāve been incredibly thorough. You also have to consider ā if you do manage to get a diagnosis ā what are the realistic chances that it will be something that is treatable?
At this point, if he were mine, I would be looking to pull his shoes & turn him out for 6-12mths. If no improvement, then I would euth.
Iām sorry youāre going through this ā jingles for the best possible outcome for you both.
Worsening during rest and lack of response to the bute trial make me think itās neurological. Iād x-ray the spine and put him on Marquis for 30 days. IMHOā¦ we either donāt have the EPM test quite right, or Marquis cures something else that we donāt know how to test for. Iāve seen several horses with borderline titers, e.g. 1/500, respond to treatment.
sounds like a wobbler.
Also recommend a bone scan
This. Iād also look at the neck.
To me, having experienced similar at the same age, this sounds like a stifle issue - a combination of slight catching with upward patellar fixation- and then secondary soreness caused by this. How you describe this- the hitch, worse with time off, spooky- just screams UPF to me. It doesnāt show up on any x-ray or u/s and if the horse is not doing a full, complete catch, many vets dismiss this possibility. It can also make horses spooky because they donāt know whatās happening or when it will happen.
I would obviously investigate further but focus in on the stifles a bit more. Lots of other good suggestions too. A bone scan could help or show nothingā¦itās so hard to figure this stuff out and often takes a long time and lots of cash flow.
btw, I ended up retiring my guy at 6. He will b 8 soon. Heās hanging out at my daughter in lawās family farm about 2 hours away. I wish it could have turned out differently, but I found a new show horse and still maintain ownership of him which is important to me. I do wish you the best.
Another vote for neck given all the things that have not worked and the spookiness. A clientās horse has also had some hind end issues going on for months. He is older so there were some things found, but treatments havenāt really worked. His main lingering issue is having trouble holding leads. This was a h/j horse with no cantering problems previously. Just imaged his neck today and there are some significant changes: osteoarthritis, enlarged facets and effusion. 
Having been in your shoes also with a talented youngster, please take a look at the neck and back. It might be treatable.
Depending on the breed, you might also look into PSSM.
Wobblers (compression of the spinal cord in the neck) also wont show up with any nerve blocks or traditional ways to identify pain. Its not pain causing it, its blockage of the signals getting to the hind end. I had one and he couldnt maintain canter in the hind end, backed up funny and dragged the toes square on the hind feet.
Ive seen others with different symptoms tho too.
OP ā I think itās important to remember that itās your horse and your decision how much you spend and how far you pursue this. You have gone above and beyond what many owners would do ā you and +4 different vets have ruled out most common & some less common issues. Itās ok to try 1 or 2 or 5 more things. Itās ok to try 0 more things.
COTH is great for ideas and support and suggestions (and I love the Horse Care forum because of this huge knowledge base). But sometimes I think it means that you feel obliged to keep going down the rabbit hole of the lame horse. Iāve done this myself in the past ā āthis next thing might be it!ā ā and I wouldnāt do it again.
Good luck with whatever you decide
He sounds like a really nice boy with a great brain. I highlighted things above that stood out for me. What breed is he? The first thing that stood out is ālazyā and heās only 4. Lazy is a little odd for a baby. Depending on his breed, a muscle or metabolic disorder is possible. Then came all the other things that popped out at me. After all this, did anyone ever test his selenium? I see Vitamin E was tested, but no mention of selenium. These two are often tested together. If you havenāt tested selenium, before you do anything else, test SE.
This all makes me wonder about his diet. What exactly did he eat before you got him and what all are you feeding him now? Any vitamins? Did you do a PPE and any x-rays? Do you know if heās ever slipped while being ridden or out in turnout?
I second looking into PSSM , especially type 2.
He sounds a lot like my gelding with a stifle issue. Your list of symptoms is basically what I was dealing with as well. He had the stifle ligament splitting procedure done and heās back to full work. You could try a course of Estrone injections to see if that helps - my guy had a very positive reaction to estrone but it wasnāt quite enough to get him over the issue. I would not hesitate to have the ligament splitting procedure done - it was about $500 and he was off for about two weeks with turnout. Good luck!!
Is he a large young horse? Had he grown during that 6 months or at the end of the 6 month working period? Did the vets notice any weakness in the stifle? How lame is he? Do you have any video?
What jumped out at me is slight hitch and then worse with time off. That sounds like upward fixation of the patella or at least partial, maybe even some minor damage to stifle ligamentsā¦happened to my horse and vet prescribed a very specific exercise program before he would even consider injecting and then was so pleased with our progress he injected only hyaluronic acid.
I wouldnāt say that lazy is necessarily odd for a 4 year old depending on the horse. My big warm blood gelding was a quiet, calm, saint until he turned 5 1/2.
Also, spooking might be his way of telling you he is sore. They have different ways to let us know.
Good luck.
This was my same thought. Looking into a mechanical stifle issue like UPF will not cost much so itās something to consider.
Thank you for all your input, it is much appreciated. I know that I have done about as much as I can do, but this post was intended to make sure I cover all bases before making a final decision on what do with him. Iām new to the forum and not sure how to post individual replies to your comments. This will have to serve as an overall reply:
He is a quarter horse, so the laziness is a bit expected, but that also means he could be a potential candidate for pssm (although both sides are 5 panel NN). I just sent a hair sample to equiseq to get it tested for pssm type 2 but I wonāt know the results for a bit. As far as UFP, I have mentioned it to my vets but they have all seemed pretty dismissive of it given what they have seen. I forgot to mention we have injected the SI and Stifles and had no response, but UFP is not something Iām completely ruling out. I donāt believe we have tested for selenium so that may be something to look into and should be a simple blood test. Lastly, I think that looking into the neck and/or kissing spine is a good suggestion as we have not taken a deep look into the spine yet.
My options are really to do the bone scan as a last and final diagnostic and go from there depending on the prognosis or send him home to the Midwest to go live out in a pasture with my retired boys. I currently live outside of NYC, so unfortunately it is a bit cost prohibitive to keep a horse here that doesnāt have a job, even if boarded in a pasture or layup facility.
@BMan022815 I would do neck x-rays before bone scan. Itās cheaper and Iāve heard it can be done on farm. My horse has the following similar traits/symptoms and is going for neck x-rays tomorrow:
-young
-large (not sure if yours is)
-QH (well, half paint)
-lazy
-hind end lameness, although on and off
-stifles suspected but not improved
-nothing else obvious
-slightly suggestive neuro exam (my horse had multiple neuro exams and what I have learned is different vets have different opinions on what to grade a horse. where one vet saw āslownessā, another saw 1-2 neuro. IMO if it is affecting your horses gait and/or training it may be more than just minor)
