Jump rope alot. Also do calf lifts. Plus if you have ankle weights you can put them on and lower your hoop a little and jump and try to get the rim. When it becomes easy put the hoop higher.
One thing is to keep jumping. lol.
Calf raises, squats with light weights, squats with dumbbells, and jump-roping.
At your height, dunking shouldn't be important, for the fact that, I'm positive, even when you can dunk, you won't be dunking over people in real games.
You'll be a PG, and need to run your team. Not try and be a highlight dunker.
Work on your speed, your shooting, quickness, and first-step, and your ball-handling.
Then, if you do grow, you'll have the fundamentals down, and you'll have good athleticism to dunk.
I think you'll grow some more, so don't worry about increasing your vertical.
Yeah, don't worry about dunking just yet.
BTW, I bet you got that knee injury from trying to jump to much, or too high, and you landed wrong, huh?
Focus on the fundamentals, work on your strengths, and round out your weaknesses, so, when you do grow, like I said, you'll be that much more of a better, valuable player.
Dunking isn't all that. I know a lot of people who are highlight reel dunkers, but they say dunking is boring after awhile. lol.
Well, I don't know what to tell you.
But, I did hear that jumping style plays apart in whether your vertical increases or not. Because if you jump wrong, you may not jump as high. If you jump a certain way, you'll explode up to the basket.