If Luke Skywalker hadn't lived so long ago, and so very far away, he might have gone to Touch Bionics for his replacement hand. The i-Limb is supposedly the world’s most advanced bionic hand. It works on the usual myoelectric system, which uses electrodes to detect electrical signals from muscles and translate them into movement, but Touch Bionics have brought some innovations to the game.
A problem with robotic hands is the lack of tactile feedback. The human hand can feel when it has a good grip. A bionic hand keeps going, and can crush delicate objects. The i-Limb hand has stall-detection, which tells the hand when it has exerted enough pressure. The hand is also modular, so that a doctor can "swap out fingers" in minutes instead of sending the whole unit in for repair. There is also the brilliantly named "Thumb Parking" function, which stops it getting tangled when dressing, for example.
Most amazing of all, though is how natural these things look. The photo above features an i-Limb hand. Can you tell which it is? Touch Bionics also offer the a plain plastic version, which they say is popular with military personnel. It's not quite Terminator 2 style, though; it has a thin plastic sheath to protect against dust and water and to provide grip. But it still looks a lot nicer than the traditional pirate's hook.