Impact of body mass index on robotic-assisted total knee arthroplasty outcomes: A retrospective cohort analysis.

Abstract

Obesity is a growing global health concern and a known risk factor in total knee arthroplasty (TKA). With an increasing number of obese patients requiring TKA, it is essential to understand how obesity influences clinical outcomes and complication rates. The objective of this study is to investigate the impact of obesity on clinical outcomes and complications in patients undergoing robotic-assisted TKA (RA-TKA). A retrospective cohort study was conducted on 216 patients aged ≥18 years who underwent RA-TKA between 2019 and 2023, with a minimum postoperative follow-up of one year. Patients were stratified into three body mass index (BMI) categories: <25, 25-29, and ≥30 ​kg/m². Demographic, intraoperative, and postoperative variables-including tourniquet use and time, implant type, hospital stay, and complications-were compared. Statistical analysis was performed (p < 0.05). Two hundred sixteen patients (91.5% follow-up rate) were evaluated at a mean of 34 months, postoperatively. No statistically significantly difference was found among the BMI groups in terms of age, sex, use of tourniquet, hospital stay, or use of stem implants. A statistically significant difference was observed only in the group of BMI <25 ​kg/m² regarding arthrofibrosis. When patients were grouped as a BMI <35 vs a BMI ​≥ ​35 ​kg/m², a higher complication rate was noted in the ≥35 ​kg/m² group (18.2% versus 7.2%), though the difference was not statistically significant (p ​= ​0.09). This study found that the difference was not statistically significant in the overall rate of postoperative complications among patients with obesity undergoing RA-TKA. However, a nonsignificant trend toward a higher complication rate was observed in patients with severe obesity (BMI ≥35 ​kg/m²). Interestingly, a statistically significant increase in arthrofibrosis was found in patients with BMI <25 ​kg/m², a finding that contrasts with the current literature. Level III.