Accuracy of Component Placement in Robotic-Assisted Total Hip Arthroplasty.

Robotic-assisted total hip arthroplasty (THA) is a recent platform introduced to decrease the risk of malpositioned components. The goals of this study were to determine whether intraoperative data on robotic-assisted THA acetabular component position accurately predict postoperative radiographic acetabular component position and to determine whether intraoperative data on robotic-assisted THA leg length and offset accurately predict postoperative radiographic leg length and offset data. In 146 patients, pre- and postoperative radiographs and intraoperative component measurements were reported for acetabular inclination, anteversion, leg length change, and offset change. Component position obtained by the robotic system and radiographic data were compared with subgroup analysis for the posterior and direct anterior approaches. The average difference between groups was 3.3°±3.1° for inclination, 2.9°±2.3° for anteversion, 3.0±2.3 mm for leg length change, and 4.0±3.1 mm for change in global offset. Correlation between the robotic system and postoperative radiographs was within 10° for 95.9% of cases for inclination and 99.3% for anteversion. Posterior approach correlation was within 10° for 97.1% of cases for inclination and 100% for anteversion. Anterior approach correlation was within 10° for 92.7% of cases for inclination and 97.6% for anteversion. Intraoperative data on component position obtained from the robotic system compared well with radiographic data on component position. Surgeons must remain vigilant to ensure outliers related to robotic system malfunction do not occur. [Orthopedics. 2016; 39(3):193-199.].