The guys are right, Chris, the Duallist could be a solution for you, but you would need to re-learn how to play bass drum.
The Duallist works by having the upstroke of your foot control the slave beater on the pedal. It can be very difficult to get notes to space evenly, and if you've been playing for a long time, you'll totally have to re-train your right foot and leg muscles to handle that pedal.
If your ankle is hurting from lack of ergonomics, I would suggest looking at this pedal, the Off-Set. A buddy of mine here in Pennsylvania makes them. They've been given outstanding reviews in Modern Drummer Magazine, and the action on the pedals are nice and light, so that may help. Here's the link:
http://pointtremolo.com/pdf/off-set_basspedal.pdf
(You will need Adobe Acrobat to open the file. Enjoy.)
Kevin
_________________
Me, My Story, and Pics Of My Drums:
http://www.saludacymbals.com/c/ksiegel.html
Proud to endorse Saluda Cymbals since 2006.
Howie is my homie. Word.