A cup impactor (1, 1′；, 1″；) is provided, adapted to assist a surgeon in controlling implantation of a cup prosthesis (9). The impactor has an impactor body (8), a drive train assembly (71), an impactor nose (38), and a clamping handle (5). The impactor body (8) has on its proximal end, an impaction plate (7) connected thereto, and an impactor handle (6) formed thereon for handling by the surgeon and, on the distal end, an impactor cup support portion (8a) having a receiver recess (8b) therein. A drive train assembly (71) has a prosthesis engaging interface (11) at a distal end thereof, and a proximal end on which a positioning knob (2) is formed. The assembly (71) received and rotatably mounted in the receiver recess (8b) of the body (8) so as to expose the prosthesis engaging surface (11). An impactor nose (38) mounts on the distal end of the impactor body (8), through which the prosthesis engaging interface (11) extends. A clamping handle (5) pulls distal portion of the drive train assembly (71) and therefore any cup prosthesis (9) attached to the engaging interface (11) against the impactor nose (38) so as not to strain the proximal end of the drive train assembly (71).
