While its normal counterpart, Swordback Hold, increases chances of Open Wounds, Lance Guard increases chances of Deadly Strike. When combined with other equipment that increases Deadly Strike (e.g. Coldsteel Eye, Gore Rider or others), a physical fighter could have an extremely high chance of inflicting a Deadly Strike regularly, and dealing large amounts of damage.
However, besides its offensive bonus, Lance Guard is defensively lacking. It returns 47 damage back to attacking enemies, but in Nightmare and Hell difficulties, this is minimal. When combined with Lance Guard's Faster Hit Recovery, the returned damage can in fact be a way for a physical fighter to gain an upper hand if hit; an enemy will be too busy flinching from the returned damage after hitting the character to properly fight back.
Lance Guard, on a side note, gives a bonus to life as well. Although ideally by the time a character receives Lance Guard, they would already have a large enough Vitality, Lance Guard's bonus helps a little.
Required Level: 35
Required Strength: 65
Chance to Block: