A wrist support would help, but to truly eliminate the back-up ball, you must learn the proper release! A wrist support will help to stabilize your wrist, however, I would try the following:
Picture a clock and hold the ball with your thumb at 11 o'clock and your fingers at 5 o'clock. Maintain this hand position. Just as you are releasing the ball, rotate your fingers counter-clockwise and "shake hands with the pins". In other words, your fingers will now be at roughly 3-4 o'clock and your thumb will be at 9-10 o'clock.
This should give you a medium hook depending on your lane conditions.
It will take practice to eliminate the back-up ball so be patient!
