Ash,
If it's been that long for you then you have probably traveled down all the roads but I thought I'de throw it out anyway.

For the mouse operations you may HAVE to do, a palm type trackball like the Kensington Mouse Expert Pro removes the finger cupping that comes from a normal mouse and eliminates the wrist issue. I lay the butt of my palm on the ball and use more forearm movements. The buttons can be hit with small movements, almost no finger tendon use. the feature that enacts "Precision movement" elimnates the need to strain the hand to be pixel precise.

JFYI.
Burr