sides of joint. Total refers to both sides of the hip joint - are replaced often metal on one side (the ball) and a special plastic on the other side the cup. Partial is where only one side is replaced usually the ball.
Different. A half a hip replacement is called a hemi arthroplasty. It is typically used for fractures and replaces only the ball at the top of the femur. The hip socket is native. In a total hip replacement both the ball and the socket are replaced.