i remove all broken leaves from my swords. i read somewhere that leaving them can have an adverse effect on the plant as it starts to rot, but im not sure if thats true or not as ive not hung around to find out. cut it off from near the crown. i prune my swords now and then to promote new growth, and i have shoots coming off them. so theres definately no down side to pruning, except it can be a bit unsightly at first if you go over the top with the pruning. but since your only talking about cutting off the one leaf that should not be a problem.
hope this helps.