ligament with core lesion

[JCHobby]

Hi
My pony has a core lesion in the stifle ligament. Per the vet the lesion appears stable, but not reducing in size necessarily. Horse travels sounds and is gradually working up his strength and abilities. Still, I would hate to over stress and cause a catastrophic failure. What treatments/success has anyone here had with closing up and healing these long term lesions?

Thanks. Jill