Christ, people... I think this thread is going a
little off topic..... If I remember correctly, the original post was in essence about adding close-combat weapons to OFP. NOT about human anatomy.
ANYWAY, I know this has been attempted before, more than once. I'm not sure if anybody ever came up with a good hand-to-hand weapon, but I know somebody was working on a Katana at one point. And I saw a drill and a chainsaw at one site, but I dont' think they worked very well. What I would do is try searching the official forums a bit, and see what turns up; that's where I saw people working on this stuff before.
Now, as far as usefulness:
In standard OFP missions, a bayonette might be usefull at times. Mainly for close quarters fighting, like in an urban environment. I know there have been times where I have run out of ammo with an enemy really close to me, and it would have saved my life to be able to hit the spacebar and then run up and stab him. In those cases, pulling out your pistol just takes too long. Also, I think it would just be more fun to be able to charge a guy 10 meters away and stab him to death, rather than just shooting him. I tend to charge guys anyway, then just shoot them at point-blank
I don't think a knife would be very useful in standard ofp missions, though, since you would have to switch weapons, and it would be better just to pull out a pistol. However, in non-standard missions, a knife or sword would be great fun. Think about a zombie-killing mission, for example. Or how about an urban mission, where there is a gang-brawl in the streets. A big melee with chains and knives would be pretty cool. And, if anyone ever made a WWI or earlier mod, you would certainly run out of ammo quickly (and shoot slowly), so swords (and bayonettes especially) would be more useful. I don't think anyone will ever make a US civil-war mod, but if they did, swords and bayonets would be used as much as bullets!