Index surgery and ninety day re-operation cost comparison of robotic-assisted versus manual total knee arthroplasty

This study looks to compare early costs of index surgery and re-operations of robotic-assisted total knee arthroplasties (rTKA) and manual total knee arthroplasty (mTKA) re-operations within 90 days.

The Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database was queried for patients undergoing rTKA and mTKA at our institution from January 1st, 2018, to March 31st, 2021. Primary outcomes were the day of surgery and overall encounter variable direct costs (VDC). Secondary outcomes included 90-day re-operations and costs.

One thousand two hundred seventy-six (21.2%) patients were in the rTKA cohort, while 4740 (78.8%) were in the mTKA cohort. When comparing rTKA to mTKA, rTKA had higher median total encounter costs (p < 0.001) and higher encounter VDC costs (p < 0.001). TKA had higher day of surgery total VDC (p < 0.001), VDC supplies (p < 0.001), and VDC of post-op recovery (p < 0.001). Multivariate linear regression showed no relationship with age, BMI, OR time, or LOS with cost for rTKA or mTKA.

Results from our study show that rTKA is associated with a higher index surgery costs, and no difference in 90-day re-operation costs. The main factor driving increased cost is supply cost, with other variables between too small in difference to make a significant financial impact. Future studies should focus on post-operative costs including readmission and episode of care costs and should consider cost to the payor as opposed to VDC. rTKA will become more common, and other institutions may need to take a closer financial look at this more novel instrumentation before adoption.

III, retrospective cohort.