It won't hurt, in fact even if it doesn't help that one specific injury you'll notice an overall difference if you try the glucosimine/chondroitin supplements. I also have Wrigley (hip dysplasia) on Adequan once a month & that has helped tremendously.
However, stay off the aspirin. If he seems to be in severe pain, a baby aspirin once a day for 3 days is ok, but is NOT a long-term pain reliever. There are better canine drugs made for long term pain relief (Deramaax, Metacam, etc.) that help better without the side effects that aspirin can have. There's also a newer product out there that is shown to have even fewer side effects than the 2 I mentioned & we have a vet using it on her dog with great success (no diarrhea, etc.) so let me get the name of it for you as well.
As for the jumping, I think it's time to invest in a doggie ramp or doggie stairs for your pooch. Even on his good days he doesn't need to be jumping around on that leg.
I hope he gets to feeling better.