Is there an indication for simultaneous bilateral knee arthroplasty in morbidly obese patients? Should the patients’ request for simultaneous operation be considered?

PURPOSE: This study aimed to analyse the safety of simultaneous bilateral total knee arthroplasty (SBTKA) surgery by comparing morbidly obese (MO) patients with obese patients. METHODS: SBTKA was performed to 494 patients by a single surgeon in a single center between 2014–2020. The patients followed for a mean of 26 months. They were divided into two groups according to body mass index (BMI) as MO (BMI> 40 kg/m2, n = 65) and obese(O) (BMI = 30–39.9 kg/m2, n = 429 patients). The groups were compared in terms of wound healing problems (WHP), mobilization time (MT), operation time (OT), prosthesis infection, aseptic loosening (AL), early complications, revision, and length of hospitalization using univariate and multivariate logistic regression analyses. RESULTS: Logistic regression analysis revealed significant differences in the clinical outcomes and complications between MO and O patients. Parameters such as length of stay, OT, MT, WHP, debridement, medial retinaculum detachment (MRD) and AL, and short-term complications such as acute kidney injury (AKI), and pulmonary embolism (PE) incidence were significantly higher in the MO group. Among the MO patients, the clinical outcomes were worse than those among the O patients, and the complication incidence was higher. CONCLUSION: We do not find SBTKA surgery feasible in morbidly obese patients due to the high complication rate and unsatisfactory clinical outcomes. We suggest that the patient’s request to undergo SBTKA should not be taken into account, and that staged surgery be preferred.