(a) Antero-posterior pelvis radiograph of a 75-year-old woman with severe bilateral hip osteoarthritis. During the right THA surgery, the acetabular cavity was reamed to 47 mm. A monobloc acetabular component of 48 mm was implanted with a DM polyethylene head of 41 mm (28 mm metal head). A polished tapered stem was cemented. (b) Post-operative anteroposterior pelvis radiograph.