Fig. 6
![Fig. 6](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13018-018-1046-0/MediaObjects/13018_2018_1046_Fig6_HTML.png)
A typical case showing CT scan might be insensitive to detect screw loosening. a Anteroposterior X-ray showed radiolucent zone and double halo around the screw (black arrow) which indicate screw loosening. b Lateral X-ray showed that the same screw was pulled out (white arrow). c CT scan showed no gap around the same screw