Cybernetic Leg Prosthesis - IGN
Attaching a cybernetic prosthesis requires the Cybernetic Surgery feat (see page 83). Once attached, the cybernetic replacement performs as well as the original limb or extremity. Common cybernetic prosthetics include arms, hands, legs, feet, and various internal organs. In addition to the cost of the prosthesis, the recipient must also cover the cost of the surgery (see Table 8-9: Services and Expenses, page 141).
Cybernetic Arm Prosthesis - IGN
Because the Force is present in all living things, but not machines, creatures with cybernetic prosthetics take a -1 penalty on Use the Force checks for each prosthetic replacement (to a maximum penalty of -5).
Cybernetic prosthetic devices are unusual, but hardly rare. Luke Skywalker gains a cybernetic replacement for his right hand, lost in battle against Darth Vader-who, in turn, had much of his own body replaced with cybernetics years before.