Trench Knife

The Trench Knife is a melee weapon that appears in the Operation: Anchorage DLC pack for Fallout 3.

Although used during the simulation, you can obtain it for use in the Capital Wasteland by retrieving it from the sealed armory in the Outcast Outpost after completing Operation: Anchorage. It can be repaired using standard Combat Knife.

The only real difference between this and the Combat Knife is that it has a spiked handle guard and a slightly longer blade.

Trivia

 * This is a weapon used when jumping into trenches for close quarters operations.