I've been trying to use the IK bone constraint with my rigs as it makes animating much easier, however I find that when I apply the constraint, I get twisting in the mesh. I've tried remedying this by adjusting the pole angle, and although that does remove the twisting, my joint will no longer be bending at the right angle in comparison to the, say for example, Elbow.R.IK, etc... This problem has happened to all of my models that I've applied the constraint to. Thanks for the help]1
Without actually seeing the the .blend file. It sounds like a possible issue involving rotation/scale. One should always be sure to apply Rotation & Scale when done. ( Ctrl + A )
Sounds like your bone roll got twisted. to recalculate it hit CTRL + N and click one of the calculation methods. if you have a mesh with fingers or other bones that are not supposed to be alligned in a 90° angle, make sure to exclude them from your selection. also you probably have to readjust the pole angle.