What technique do you use to get the boot on. Most people do it wrong, they just pull the tounge foward. Thats the wrong way to do it, you want to instead use the tounge to open the top of the boot. To do this you want to pull the tounge to the side not forward.
Certainly though for a bad ankle it will be well worth getting some good footbeds, so prob your best bet will be to take your current set up to thebest bootfitter you can find, and have them see if everything is working as it should. They can also show you the correct way to put your boots on.