An acetabular impactor aids a surgeon in controlling the installation of an acetabular cup prosthesis having a central, female aperture. The impactor includes an impactor head, housing and a locking mechanism. The housing is attached to the impactor head, the housing enclosing a drive train having, at a far end, a prosthesis engaging thread, and at the opposite end, a handle which facilitates turning of the drive train by the operator. The locking mechanism is associated with the housing which selectively locks the drive train, and thus the prosthesis, in position. The opposite end of the drive train has a latch device which enables quick removal from the housing for cleaning and sterilization.