How many years after a tendon release for c. palsy would you have to do it again because it tightened?

I could help you: In patient with spastic kind of cerebral palsy, the muscles are spastic all the time. When a surgery done to release the muscles tightness, we usually use brace to hold the joint in the corrected position to prevent the muscles from going back the old position. Also we do continuous physical therapy to prevent this from happing.If thing did not go right we have to release the muscle again.Thank.