besides the obvious inability to use two handed weapons, what are the other restrictions here? Can a medium or small shield be strapped to that forearm? Can spells still be cast?
Restrictions of a missing left hand
If you're a spellcaster, the supervising DM should have applied an appriopriate amount of spell failure. I'm actually not sure what our policy on shields is.
Small shields can be strapped to your forearm with the help of another.