Horse paces going down hill

I have a homebred 6 year old, so I know all of his history, who started switching from a walk to a pace going down hills last year. It did not seem to affect his ability to ride or drive. This spring it did, became increasingly difficult for him to perform, suspected stifles. Did a nuclear scan and it turned out to be his SI joint which was a surprise as he has done only light work. Injected the joint, some improvement but he still paces going down hill. Any ideas out there?

what has rehab been like?

What exactly was the issue with the SI? Damaged ligament(s)?

Work isn’t the only thing that injures horses. SIs can easily get injured from a hard stop in the pasture that causes the hind end to shoot forward.

After the injection he had a week of stall rest and then returned to pasture. We live in VT so nothing is flat but it is not steep or difficult. Started riding him at a walk with no issue on the flat. Improvement was shown in that he could do carrot stretches easily and I could handle his hind feet with no issues (he was unable to hold a hind foot up for more than a minute before). Also stifle issues are gone at the trot. Riding with little contact and doing basic moves. He continues to pace even in hand downhill if the grade is steeper than he can handle.

Should also mention we put him on a muscle relaxant for two weeks, no difference. 1.5cc of ace, no difference. No mention of ligament damage after the scan.

So WHAT was the injury/issue?

How long has he been in work since he came off the week of stall rest?

How long did you walk before moving to trot? How many weeks, how many minutes?

See below from the vet. He has been ridden and long lined several times a week at the walk for 15-20 minutes. Very little trotting, perhaps a minute or two. This done for 2 months after stall rest.

Soft Tissue Phase: No significant findings.

Bone Phase: Bilateral mild focal in distal-dorsal femur. Bilateral mild focal distal-lateral tarsi. Moderate-intense bilateral SI with marked asymmetry.

Radiographic Findings: Mild bilateral tarsal-metatarsal degenerative joint disease. Mild periosteal reaction in the bilateral lateral femoral trochlea.

Conclusions: Bazinga has multiple incrase bone activity, but the most serious and most likely cause of lameness is from the sacro-iliac joints. This joint disease can cause abnormal behavior and lameness issues.

Treatments: Both sacroiliac joints were injected with a combination of corticosteroids (Depo-Medrol), Neo-Predef, Amikacin, and Sarapin. This combination will decrease inflammation and pain associated with the sacroiliac joints. It may take up to 3-4 weeks for the full effect of the injections to be seen. These injections can be repeated no earlier then 4 months.

15-20 minutes of walking 3-4 times a week isn’t real rehab. It’s a good start, but it’s not a lot. Nearly every rehab from worse scenarios works up to 40-60 minutes of real walking (which is generally a lot more work than most people can do via ground driving, both intensity and duration), for at least a few weeks (and sometimes months for more major injuries) before starting in with trot work

Spend the winter walking. Walk and walk and walk some more. Start trotting in the Spring. That’s what I’d do

Have you ever seen a horse pace due to an SI injury?