This is all second hand information so take it for what it's worth. I was talking to another wakeboarder from my lake about knee injuries (I am recovering from a torn ACL right now too), and he was talking about a rider he knew that had been riding for years without an ACL. He had torn it and couldn't afford the surgery, so eventually he just started riding without it. He wore a legit brace and said it wasn't a problem as long as he took care to ride wake to wake only, never into the flats, and always hit the downslope of the second wake. It sounds like it wasn't quite as strong but he was able to ride wake to wake without an ACL.
Also, the rider I was talking to has zero lateral meniscus in one knee (they took it completely out) and is 37 years old and is still doing w2w TS FS 720s, so that is inspiring to anyone with knee problems. He said they make a brace designed to remove impact on one of your two meniscii and transfer it to only the other, so he doesn't have any significant pain/problems with only 1 of his two meniscii in one knee.