My friend had to have one of her shar-pei operted on when he was about 8 months old. His knee kept slipping out of place and he would go intermittently lame and you could see his back end was wasting over a couple of months, so they opened him up, deepened the groove and sutured it into place. He was kept to show and breed from, so she pet homed him and his new owner says he's smashing now with no signs of problems and a lovely muscular back end.
However, I'd get a crate and be very strict about no exercise if I were you because if he damages it, he'll be even worse off than if he's not operated on.
I'm a bit worried about operating on a dog who has so much skeletal growth left to do. I'm no expert, but surely this could cause more problems than it will cure? If possible, consult a specialist orthapedic vet before you go ahead.