Early post-operative outcomes following robotic vs. manual total knee arthroplasty in low- vs. high-volume surgeons.

Introduction: Primary robotic total knee arthroplasty (TKA) is associated with favorable outcomes. To further understand robotic TKA learning curve, we evaluated early postoperative outcomes of robotics vs. manual TKA, based on surgeon experience. Methods: Patients (> 64 years) from the Medicare database, with primary, unilateral, elective TKA (“index”) from October 2015 to December 2019 were identified and categorized based on robotic vs. manual surgery, and surgeon experience: low-count surgeons had < 40 cases in the 12-months pre-index; medium-low, medium- high and high count surgeons had 41-80, 81-120 and 121-160 cases, respectively. The low-count robotic cohort (RC) was compared to the low, medium-low, medium-high, and high count manual cohort (MC) for the length of the hospital stay (LOS), and rates of home and skilled nursing facility (SNF) discharge. Descriptive statistics (means and proportion with 95% confidence intervals) were performed. Results: 296 low-count robotic cases were compared to 209,494 low-count manual and 252,905 medium-low, medium-high and high-count manual cases. The low-count RC had an average LOS of 2.03 days (95% confidence intervals (CI): 1.86-2.20) vs. 2.20 days (95%CI: 2.20-2.21) for the low-count MC. 82.4% patients (95%CI: 78.1%-86.8%) from the low-count RC were discharged home vs. 74.2% (95%CI: 74.0%-74.4%) in the low-count MC and 83.6% (95%CI: 83.3%-84.0%) in the high-count MC. Discharge to SNF affected 15.2% (95%CI: 11.1%-19.3%) in the low-count RC vs. 21.0% (95%CI: 20.9%-21.2%) and 15.2% (95%CI: 14.9%-15.4%) in the low-count and medium-high MC, respectively. Conclusion: Patients operated with robotic surgery by surgeons with low yearly volume had a LOS and probability of home discharge similar to that of patients operated with manual surgery by high-volume surgeons. Patients in the robotic group also had a lower rate of SNF discharge compared to the patients in the manual surgery group, with surgeons of similar experience.