I've had a Frankenboot (great verbiage!) three times now, flown twice with it, and so I look at it this way: Do I *want* responsibility for assisting other passengers in the event of an evac? (Answer to self: No! and hell No!)
From the perspective of the likelihood of involuntary re-seating, it's more important to take care of yourself and Frankenboot first. Call the airline and explain the situation -- get it in the PRN, if you can -- so you have the best possible chance for a fortuitous outcome, e.g. a bulkhead and/or aisle in E+ -- or an op-up to C or F.
I just flew AS F a few weeks ago with said monster appendage and am sad to report that that wasn't even an altogether comfortable experience (thanks, seatmate

). Imagine, as
MileageAddict suggests, that you involuntarily end up in a middle (anywhere) or in E-: You may not even be able to fly if you can't get your foot tucked in. Give it some thought. @:-)
Originally Posted by
UpperDeckJunkie
I'll be able to take it off and have it xrayed while going through security
Here's the
good news! You are not required to remove your little friend at the c/p. It is a medically necessary assistive device and you can go straight to secondary
sans backtalk. You'll be given a brief body wanding and swab of your boot and street shoe (can stay on as well, which you "need" for stability purposes). You'll remained seated for the swabbing and they'll bring your personal belongings to you. In a sense, it's almost better than an elite-line experience.
Sorry to hear about your tendon. I ripped my clean from the calf ~9 years ago. It hurt like a muthah!