Fig. 2From: Three-dimensional technology assisted trabecular metal cup and augments positioning in revision total hip arthroplasty with complex acetabular defectsMeasurement with anteroposterior view of an X-ray. a measures the angle of anteversion, anteversion angle = arcsin (D1/D2); D1: short red line of the ellipse; D2: long blue line. b measures the angle of abduction. c shows the vertical and horizontal position of COR. A: vertical position of COR; B: horizontal position of CORBack to article page