Fig. 3From: The results of screw augmentation of acetabular cement spacers for the treatment of periprosthetic hip joint infectiona Immediately postoperative X-ray of first stage. V is the vertical distance from femoral head center to the horizontal reference line. H is the horizontal distance from femoral head center to the vertical reference line. b Last follow up X-ray before second stage operation. Vertical migration is V2-V1 and horizontal migration is H1-H2Back to article page