Lower Intraoperative and Immediate Postoperative Complications in Robotic Versus Conventional Primary Total Hip Arthroplasty: A Retrospective Cohort Analysis of Over 360,000 Patients.

PURPOSE: Although a trend of an improved alignment with robotic total hip arthroplasty (THA) over conventional methods has surfaced from recent series, it is unknown whether these results translate into meaningful enhancements in postoperative outcomes. To address this lack in the literature, we compared the perioperative morbidity and mortality with robotic and conventional THA in a large national cohort of 367,894 patients. We hypothesized that no significant differences would exist in the outcomes between the two groups.

METHODS: Records were extracted from 2016-2019 from the National Inpatient Sample (NIS) database Healthcare Cost and Utilization Project which is the largest in-patient database in the United States. From 367,894 THAs, robotics were employed for 7,863 patients. The remaining 360,031 conventional THAs served as controls. The two groups were compared for demographics, admission, and hospital stay details including costs, and mortality and morbidity data including medical and surgical complications. Descriptive statistics were used for demographic data while analytical statistics including t-tests, chi-squared tests, Fischer exact test, and Pearson chi-squared tests were used for perioperative outcomes. Statistical significance was set at p<0.005.

RESULTS: Demographic distributions between robotic and conventional THA groups displayed similar age and sex characteristics. Shorter mean lengths of stay (1.87 days) were seen in robotic THA versus conventional THA (2.33 days) while higher costs were noted for the former (mean $68,686.71 vs $66,840.39) (p<0.005). Low overall mortality (0.03% robotic, 0.09% conventional) was seen in both groups (p>0.005). Higher comparative incidences of anemia, acute renal failure, and pneumonia were seen in conventional THA (p<0.005) while no significant differences were noted for other complications including myocardial infarction, pulmonary embolism, deep vein thrombosis, and cardiac arrest (p>0.005). Among others, lower dislocation rates, mechanical complications, periprosthetic joint infection, and periprosthetic fractures were seen with robotic THA (p<0.005). Wound complications and superficial infection rates did not differ between the two groups (p>0.005).

CONCLUSIONS: Evidence has emerged from our results to support more routine adaptation of the robotic option of performing a THA. These can be based on lower local, systemic, and mechanical complications as demonstrated by the present study. Further evaluation of these results in follow-up would help establish the foothold of robotic surgery in total hip replacement in the modern context.