I've been postponing cheilectomy surgery on both feet (for bone spurs in MTP joint as result of osteoarthritis) for some time because I'm afraid of how it will impact my dancing. My understanding of fusion in the MTP joint is that it removes all flexibility in the big toe joint, meaning your foot will pretty much have to stay flat, wearing heels is not an option, and you can no longer 'rise' onto the ball of your foot. I'm no doc; just read a lot (and take everything with a grain of salt). Have you asked your doc? If it's that important to you, I'd look for a doc who specializes in sports medicine, or even better, treating dancers. And get a second opinion. Try alternative treatments if you can (physical therapy can work miracles).
Wish you the best & hope you'll keep us posted on the outcome!