Improved accuracy of a novel fluoroscopy-based robotically assisted THA system compared to manual THA.

Abstract

Accurate acetabular cup position remains a persistent challenge in total hip arthroplasty (THA). Studies investigating the early outcomes of robotic-assisted THA (RA-THA) systems have shown improved cup placement compared to manual THA (mTHA) approaches, however, contemporary robotic platforms are reliant on pre-operative CT imaging. The goal of this study was to analyze the accuracy of a novel, fluoroscopy-based RA-THA system compared to an unassisted mTHA approach and determine the effect of the robotic system on operative time. We performed a retrospective cohort analysis on a consecutive series of 198 patients who received mTHA and RA-THA between March 2021 and July 2022. The primary outcome of interest was the accuracy of acetabular component placement, defined by average cup inclination and anteversion. Secondary outcomes included the proportion of acetabular cups positioned within the Lewinnek safe zone, operative time, and overall room time. The RA-THA group demonstrated significantly higher accuracy of acetabular anteversion to target compared to the manual group (18.5 vs. 21.7˚; p < 0.001), and had a significantly greater proportion of acetabular cups placed within the Lewinnek safe zone (81.6 vs. 59.0%; p < 0.001). The RA-THA cohort had longer operative times compared to mTHA group (39.0 vs. 35.3min; p = 0.003), but no difference was seen in total operating room time (101.2 vs. 101.2min; p = 0.982). This study demonstrates that the use of a novel, fluoroscopy-based, pin-less THA robotic platform increased the accuracy of acetabular cup placement, including a 22.6% improvement in safe zone placement, compared to mTHA approach, with no increase in overall case time.