Background: The use of robotic total knee arthroplasty has become increasingly prevalent. Proponents of robotic total knee arthroplasty tout its potential to not only improve outcomes, but also to reduce costs compared with traditional total knee arthroplasty. Despite its potential to deliver on the value proposition, whether robotic total knee arthroplasty has led to improved outcomes and cost savings within Medicare's Bundled Payment for Care Improvement initiative remains unexplored. Methods: Medicare beneficiaries who underwent total knee arthroplasty designated under Medicare severity diagnosis related group 469 or 470 in the year 2017 were identified using the 100% Medicare Inpatient Standard Analytic Files. Hospitals participating in the Bundled Payment for Care Improvement were identified using the Bundled Payment for Care Improvement analytic file. We calculated risk-adjusted, price-standardized payments for the surgical episode from admission through 90-days postdischarge. Outcomes, utilization, and spending were assessed relative to variation between robotic and traditional total knee arthroplasty. Results: Overall, 198,371 patients underwent total knee arthroplasty (traditional total knee arthroplasty: n = 194,020, 97.8% versus robotic total knee arthroplasty: n = 4,351, 2.2%). Among the 3,272 hospitals that performed total knee arthroplasty, only 300 (9.3%) performed robotic total knee arthroplasty. Among the 183 participating in the Bundled Payment for Care Improvement, only 40 (19%) hospitals performed robotic total knee arthroplasty. Risk-adjusted 90-day episode spending was $14,263 (95% confidence interval $14,231-$14,294) among patients who underwent traditional total knee arthroplasty versus $13,676 (95% confidence interval $13,467-$13,885) among patients who had robotic total knee arthroplasty. Patients who underwent robotic total knee arthroplasty had a shorter length of stay (traditional total knee arthroplasty: 2.3 days, 95% confidence interval: 2.3-2.3 versus robotic total knee arthroplasty: 1.9 days, 95% confidence interval: 1.9-2.0), as well as a lower incidence of complications (traditional total knee arthroplasty: 3.3%, 95% confidence interval: 3.2-3.3 versus robotic total knee arthroplasty: 2.7%, 95% confidence interval: 2.3-3.1). Of note, patients who underwent robotic total knee arthroplasty were less often discharged to a postacute care facility than patients who underwent traditional total knee arthroplasty (traditional total knee arthroplasty: 32.4%, 95% confidence interval: 32.3-32.5 versus robotic total knee arthroplasty: 16.8%, 95% confidence interval 16.1-17.6). Both Bundled Payment for Care Improvement and non-Bundled Payment for Care Improvement hospitals with greater than 50% robotic total knee arthroplasty utilization had lower spending per episode of care versus spending at hospitals with less than 50% robotic total knee arthroplasty utilization. Conclusion: Overall 90-day episode spending for robotic total knee arthroplasty was lower than traditional total knee arthroplasty (Delta $-587, 95% confidence interval: $-798 to $-375). The decrease in spending was attributable to shorter length of stay, fewer complications, as well as lower utilization of postacute care facility. The cost savings associated with robotic total knee arthroplasty was only realized when robotic total knee arthroplasty volume surpassed 50% of all total knee arthroplasty volume. Hospitals participating in the Bundled Payment for Care Improvement may experience cost-saving with increased utilization of robotic total knee arthroplasty. Published by Elsevier Inc.
