Originally Posted by
ATLAviator
...Most importiant is to minimize degrees of flexion of my knee...
...wonder if longer crankshaft will irritate knees more.
Of course the longer crank
ARM would irritate your knees more.
Get whatever bike you want, but have very short cranks installed. Aim for the shortest you could find, 150 mm are commercially available, and the forum inmate AnthnyG could advise you on obtaining even shorter ones.
In case you can't get the bike with short cranks from get-go, and aim to replace the cranks later on, the type of the bottom bracket becomes a consideration, and it's safer to ensure that it's a square taper in English thread.