Scoliosis preventing me from joining the army?

Hey, I recently discovered at the doctor's that I might have scoliosis. I know that to a certain degree that it could disqualify me from joining the army. I'm signing a Ranger contract, and it has always been my dream to join. I'm 6'2 and athletic, I play basketball and run cross country. I'm done growing, so what could doctor's do to fix my spine? And how hard is a medical waiver to come by if my scoliosis is over 20 degrees?