gms | German Medical Science

Objectives: The use of robotic systems in knee arthroplasty is increasing and allows precise implementation of 3-dimensionally planned patient-individual prosthesis positioning. In order to become a promising model for the future, surgical robots must also prove themselves from an economic point of view. In this analysis, economic data on total knee arthroplasty (TKA) implanted with a semi-active robotic assistant (MAKO Stryker) was compared to data from knee prostheses operated using a strictly manual method.

Methods: The cost of comparable procedures from robot-assisted (TKArobot) and manually performed (TKAmanual) operations from the years 2020 and 2021 at a maximum-care hospital were retrospectively analyzed. Case-related data on cost items such as material, prosthesis, laboratory tests, radiological diagnostics, consults, ward, OR and anaesthesia was collected based on documentation and billing data. Revenue structure was analyzed and compared. Length of hospital stay and adjusted Case Mix (aCM) information was collected.

Results and conclusion: The cohorts consisted of n(robot)=157 and n(manual)=279 patients. Length of hospital stay differed significantly by 1.02 d (robot 5.94 d vs. manual 6.96 d) in favor of the MAKO patients. In total costs were lower for TKArobot than for TKAmanual (-11.0%) and standard deviation differed by a factor of 2.6 (TKAmanual > TKArobot) implying a more consistent cost expectation for TKArobot. The cost factors blood products, material, OR and ward contributed significantly lower to TKArobot total intervention cost than in TKAmanual (TKArobot/manual: blood 0.36/1.15, material 19.96/23.3, ward 24.35/25.49% of total cost). TKAmanual average revenues were slightly higher than for TKArobot (1:1.08) but significantly influenced by a higher aCM (TKAmanual 1.78–5.57; TKArobot 1.31–1.82) and consequently correlated with intervention-related complications and extended treatment. Despite this fact, revenue-cost-ratio (revenue-cost/total revenue) was better in TKArobot (3.05%) versus TKAmanual (-0.07%).

The revenue-cost-ratio in favor of the MAKO intervention resulted from lower operation-related cost with similarly structured revenues from DRG, nursing budget, surcharges and discounts compared to the manual intervention. Higher revenues for TKAmanual were mainly based on surcharges and case mix adjustments but also related to higher case cost. Advantages and disadvantages of implantation with the MAKO robot should therefore be weighed considering the patient profile (CMI, comorbidities) and acquisition costs. Further research defining those patient profiles and cost-benefit ratio of robot-assisted TKA needs to be conducted.