Can Robotic Assistance Overcome the Challenges of Obesity in Aseptic Revision Total Knee Arthroplasty? A Preliminary Report

Background: Obesity is a known risk factor in orthopaedic surgery, but its effect on outcomes in robotic-assisted revision total knee arthroplasty (rarTKA) is still uncharted. This study examines the association between body mass index (BMI) and key perioperative and early postoperative outcomes in aseptic rarTKA. Methods: This retrospective, observational study analyzed 55 patients who underwent off-label aseptic rarTKA using the Stryker Mako system at a single academic center between 2020 and 2025, excluding patients with infection-related revision indications. The cohort was stratified into high and low BMI groups using the median BMI of 34.1 kg/m². Outcomes included operative time, length of stay (LOS), postoperative range of motion (ROM), and 30-/90-day readmission rates. Results: There were no statistically significant differences between the high BMI (n=28) and low BMI (n=27) groups in operative time (175 vs 176 minutes; p=0.898), LOS (31.71 vs 30.22 hours; p=0.779), 2-week postoperative ROM (107.5° vs 102.5°; p=0.474), or 30/90-day readmission rates (17.9% vs 7.4%, p=0.449 and 14.3% vs 7.4%, p=0.700, respectively). Conclusion: In this study, elevated BMI was not associated with inferior perioperative or early postoperative outcomes in aseptic rarTKA patients. These preliminary observations highlight the potential of robotic technology to mitigate the technical challenges associated with obesity in complex revision cases. However, this study is severely limited in power and only assesses short-term outcomes. Larger prospective studies are needed to validate this conclusion, especially in comparison to manual rTKA.