treatments for stifle problem?

[Cyndi Craig <cyndi.craig@chron.com>]

need some input from the collective wisdom of you vets out there.

i have a 10-year old gelding i have been doing LD with for about 2
years. he's completed 8 rides just fine, our conditioning program is
doing its job, and was contemplating trying a 50 later this year. time
is my limiting factor, since i compete seriously in open dressage with
my other horse.

this horse has a solid dressage base, in that that is ALL he did prior
to starting LD, and i still use the same principles when riding him LD
as i did dressage..(i have owned him since he was a weanling).

ok. here is the problem. the past few weeks i've noticed he has 
cross-cantered on the right lead several times when out on the
trail...more than normal.. this is something he has done every once in a
while his entire life (he does not have a really great balanced canter,
naturally)....he is stiffer to the right, despite the life-long
suppling...then, the past week or so, 2-3 times out on the trail at a
canter, his right hind felt like it just went out from under him..and he
hopped on three legs until i got him stopped..walked a bit..then he was
fine.

i took him to my vet, and his opinion was his stifle is locking up
briefly, causing these periods. he shows absolutely no clinical lameness
whatsoever.

my vet gave him a shot of legend, hoping that would help the sliding
part of the stifle keep from getting hung up..but then i have been told
by someone else, that that will have no effect on that at all.

due to an unrelated accident, i haven't been able to ride him except
once since he got the legend (10 days ago) so i don't know if it worked
or not...

i guess my question is, how would you treat this? i have heard
everything from clipping one of the ligaments in the stifle joint (after
x-raying first) to doing internal blister with iodine...

my first course of action would be to increase his suppling and
strengthening exericises on that side..canter departs to the right,
etc...but i had pretty much been doing this kind of stuff before and it
didn't PREVENT this from happening...

just looking for ideas on plan "B"...

thanks

cyndi craig and muscatyr
donerail farm
alvin, tx