While HGH is pretty good for this purpose, I would not consider that option for the following reasons:
1. It is extremely hard to find real HGH, and mostly fakes are sold.
2. Real HGH costs a fortune, so you will have to pay quite a good buck for it.
3. It will take at least 4-6 months to start feeling the full force of its effects.
Instead, better use the following stack, which will get your knee in a brand new condition. I have used it for serious elbow problems, and it was the most effective thing ever.
1. Ostarine MK-2866 at 25 mgs ED for 12 weeks (it has been scientifically proven to considerably increase the recovery speed of joint injuries, as well as bones and suft tissues).
2. N2Joint RX - this supplement has a ton of different ingredients that are meant to heal and strengthen joints. Works like a charm.
3. Nutrabol MK-677 - it has effects that are very similar to HGH, but it starts acting much faster than HGH, and it is very easy to find the real one (get it at sarms1.com).