You mentioned scar tissue affecting his gait.
I did this for a filly that could only bend her leg half way and couldn't touch her elbow and it worked great. It was like a brick wall was stopping it from bending.
Scar tissue is like a big knotted tight mess (internal tissue) so what I did was massage with my thumb deeper and deeper each day to break it up.( all over the area that was injured) then I would put obsorbine on or might have rubbed that in first, can't remember. She was back to normal in less than a month.
My vet told me that, and it worked like a charm.