Fig. 4.

Results of the twist testing for the 48-mm-diameter reaming; the additional screw fixation is effective, but it has little influence on the whole-cup fixation (a). For the 48.5- (b) and 49-mm-diameter (c) reaming, the shapes of the line graphs are different from those for the 48-mm-diameter reaming, indicating marked deterioration of the cup fixation. The cup fixation tends to increase with the increasing number of screws and the addition of screws to the outer side of the cup rather than the inner side