Back in October, my son fell when we were ice skating, and he broke his right arm. It started healing wrong and had to be re-broken to set it properly. He was casted in a full arm cast in wrist flexion. His arm was immobilized for more than two months, so when he got his cast removed, he could not get his wrist extended to neutral passively. He also had trouble closing his fingers into a fist. He did not want me to take any pictures of him using his hand right after the cast came off so I did not, and therefore I have no before and after comparison pictures.
My son’s arm was tender and sensitive after being in a cast for a long time, so he did not tolerate a lot of stretching at first. I started him out with stretching against the wall. I had him place both forearms against the wall so that his wrist would be in good alignment, and then I had him push into the wall and try to extend his wrist. With this stretching exercise, he could control how much pressure was being given to his joints.
I also had him wear a simple wrist splint (the kind that you can buy at any drug store) at night. The splint at night held his wrist in neutral and kept him from sleeping with his wrist in flexion. As his range increased, I bent the metal bar in the wrist splint to give it more wrist extension. This helped a lot because my son showed more wrist extension in the morning when he would take the splint off, and then did exercises in the warm water of the shower.
It took quite a few weeks to get active wrist extension past neutral, and then we could start working on strengthening.