Interlocking acetabular fixation screws having a threaded shaft for threading into cancellous bone and a tapered threaded head for threading into tapered threaded screw holes in a reverse hip acetabular cup. The reverse hip acetabular cup has a central stem and the threaded screw holes are drilled at an angle that allows drilling of the bone of the acetabular cavity, placement of the screws and tightening of the screws without touching the central stem and without interference from the central stem.
