Precision of Robotic Guided Instrumentation for Acetabular Component Positioning

Robotic computerized instrumentation that guides bone preparation and cup implantation in total hip arthroplasty was studied. In 38 patients (43 hips) intraoperative cup inclination and anteversion were validated by postoperative CT scans. Planned inclination was 39.9 degrees +/- 0.8 degrees and with robotic instrumentation was 38.0 degrees +/- 1.6 degrees with no outliers of 5 degrees; on the postoperative CT scan there were 5 outliers (12%). Planned anteversion was 21.2 degrees +/- 2.4 degrees and intraoperatively was 20.7 degrees +/- 2.4 degrees with no outlier of 5 degrees; on the CT there were 7 outliers (16%). The center of rotation (COR) was superior by a mean 0.9 +/- 4.2 mm and medial by 2.7 +/- 2.9 mm. This robotic instrumentation achieved precision of inclination in 88%, anteversion in 84% and COR in 81.5%. (C) 2015 Elsevier Inc. All rights reserved.