The other important question..."how do you feel on it, especially on longer rides?" Without going overboard, I'll pass on some opinions that may help you out. First off, since you just had surgery, proper recovery is paramount, re-injuring may not hit you while you are young, but years down the road you could be in for some bad issues, so that said, fit is incredibly important. I would highly recommend scheduling a professional fitting session with a reputable shop. If they give you any hard time about your "big box" bike, well just get the fitting and say your goodbyes. Also, you may want to let your surgeon know what your up to and see what he/she says. Other stuff would include not pushing huge gears, in other words, keep your cadence kinda high, this will also help to keep from bulking out your legs when it is time to go back to running (that is if you don't get completely addicted to riding...which happens here from time to time I'm told
) Again, these are just opinions on what you
could do...I'm coming from many years as a framebuilder and professional mechanic,
but I don't know you, have never seen you and have only some experience with post-surgical situations, it's pretty much impossible to do any kind of fitting over a forum post. At any rate, hope you enjoy riding as much as we do!! Welcome!