Acetabular cement mantles and component position: are we achieving "ideal" results?

Radiographs of 100 primary cemented total hip arthroplasties were studied. Acetabular component positioning and cement mantles were assessed with respect to implant type, grade of surgeon, and operated side. Seventy-eight percent of the components were eccentrically placed, with increasing cement mantle thickness from zone 1 to zone 3. Concentricity occurred in only 13% of the Charnley Ogee and in 28% of the IP Lubinus components. The Charnley Ogee was more superiorly placed than the IP Lubinus (P < .001). Surgical grade affected neither cement mantle thickness nor opening angle. In vitro studies ideally recommend concentric placement of the acetabular component. This appears difficult to achieve consistently in vivo in most patients using the components in this study.