Hi Dee, I had two vets examine my horse and they both did flexion tests and then saw him under saddle. Then they palpated his stife, back and legs. He had fluid around the left stifle, which was the one that was giving out at the canter I may do x-rays at some time in order to see how far progressed the synvovitis is and if osteoarthritis has set in. It can be managed but it sure is a bummer. Had to cancel our last show due to his current issues. I already have a 24 yr old pasture puff and certainly do not need another one!
After going to the two vets, what treatment was recommended? If nothing else, start with a period of rest and bute for 5-7 days. There is a ‘bute test’ that can help differentiate between a loose stifle and joint related or soft tissue issues. If the horse responds to bute, it’s either joint or soft tissue, but not the loose stife/upward patellar fixation- that is a mechanical issue that does not respond to bute. So a trial of bute may help. My boy was better on bute, worse when off of it. Only an ultrasound can rule out soft tissue problems such as a sprain, strain or torn ligament. More than likely, the short strided is indicitive of stifle joint issues though. So perhaps ask to start Legend or Adequan and see if that provides any relief. If not, time to get the big guns out and go for x-rays, etc. I am hoping to starve off joint injections til spring, but I want him to comfortable working all winter too, so we will see!!
Good luck and keep us posted.