Sedation always scares me, and now I have to have Baka sedated so an infection in his paw can be cleaned out, so this really caught my eye.
Two thougts: When they are sedated their body is so relaxed that their bones and joints can shift.
Also, .... and this is for real, they can also be dropped or not handled correctly when they are out, thus creating injuries. Of course, probably no one will own up to this.
I don't know about any reactions of this nature to the drug. I would tend to think not, but you never know.
You might try some chiro adustments on top of supplements like MSM, Vit C, Glucosimine, etc. White Willow Bark could provided a band aid effect (aspirn like relief). Homeopathy might also help...with the Arthritis as a whole.