Hberrie, please go back and reread Annabel's and my initial posts. We weren't recommending a *regimen* of corticosteroid injections (though for a horse in his 20s that isn't an awful idea, for a young horse, yes, I think it's a bad idea.)
We were saying that an initial joint injection of corticosteriods to interrupt inflammation followed by supportive intramuscular injections of Adequan, Pentosan or similar drug was a reasonable treatment - big difference.
I even cautioned the OP to beware of people whose knee jerk reaction was "hock injections are bad!" and drew a careful distinction between the two types.
Finally, overuse of corticosteriods are widely believed to speed up the disintegration of *cartilage*' not muscle WHEN INJECTED INTRARTICULARLY. That has never been demonstrated in a study or clinical trial, but because of the mechanism of the drug, most practitioners accept it.