I would assume (perhaps incorrectly) that any substitution that works the muscles in close to the same way would not be something you could do either: lat pulldowns, pull-ups or chin-ups (pullovers are more akin to those moves than to rowing moves). Another move that works the muscles in a similar plane is stability ball pull-ins (also maybe no doable): get on knees--or if you're advanced, on toes--in a plank position with forearms on a stability ball. Move the arms forward and back, pulling with the lats on the way back. You (not you personally, maybe, because of the limitations, but maybe?) can also do a more advanced version, one arm at a time. Get into side plank position with one arm on the ball and push out and pull in, really emphasizing the lats on the way in.
For variety, you could do a wide row (not sure of the exact name, but you do a lat row with elbows out, a bit lower then straight out from the shoulders, rather than back by the sides).