Removal of Well-Fixed Cementless Acetabular Components in Revision Total Hip Arthroplasty

The Zimmer Explant Acetabular Cup Removal System (Warsaw, Indiana) has been touted as a superior method for removing well-fixed cementless acetabular components while minimizing bone loss; however, no comparative data support this. This study compares bone loss following the removal of well-fixed acetabular components with Aufranc gouges and with the Explant System. A review of 623 revision total hip arthroplasties (THAs) at the authors' institution between 2002 and 2013 identified cases involving the revision of well-fixed cementless hemispherical acetabular components for any reason except infection. Twenty-four cases using Aufranc gouges and 27 cases using the Explant System were included. The following surrogates for bone loss were used: (1) the difference between the initial acetabular component outer diameter (OD) and the final reamer OD; (2) the difference between the initial acetabular component OD and the new acetabular component OD; and (3) the use of impaction bone grafting. A 2-tailed Wilcoxon-Mann-Whitney test was used to assess the difference in bone loss between the 2 groups. The use of bone grafting was compared between the groups with the chi-square test. The median differences between the initial acetabular component and the final reamer (P=.004), as well as between the initial and new acetabular components (P=.002), were 2 mm less with the Explant System. Hips in the Aufranc group were more likely to have bone grafting (54% vs 26%; P=.04). These results suggest less bone loss when removing well-fixed acetabular components with the Zimmer Explant System compared with Aufranc gouges.