Simultaneous Bilateral Total Knee Arthroplasty: A Cautionary Perspective on Fat Embolism Risk despite Technical Simplification

Sir, We read with interest the article by Wasfy et al. reporting outcomes of 120 simultaneous bilateral total knee arthroplasties (simBTKA) performed using patient-specific templating (PST) with unilateral tibial stems or revision implants.1 The authors demonstrated excellent functional improvement (mean Knee Society Score increase of 65.8 ± 10.2) and notably, no cases of fat embolism or pulmonary thromboembolism (PTE), despite addressing complex knee anatomy. This favourable safety profile was attributed to avoidance of intramedullary (IM) canal violation through PST-guided bone cuts.1 While we commend the authors for this technically demanding series, our institutional experience highlights the need for caution when interpreting embolic risk mitigation in simBTKA. At M. S. Ramaiah Memorial Hospital, Bengaluru, we reviewed 37 consecutive simBTKA procedures performed between 2020 and 2025 using standard primary implants without stems or revision components. Despite the ostensibly simpler surgical construct, 2 (5.4%) patients developed postoperative PTE, including 1 (2.7%) fatality. This contrasts sharply with the zero-incidence embolic events reported in the Egyptian cohort, despite their use of stems and revision implants Table 1.Table 1: Comparison of pulmonary thromboembolism and mortality rates between the Egyptian patient-specific templating cohort and the current Indian standard bilateral total knee arthroplasties seriesAlthough PST likely reduces IM canal pressurization, our experience suggests that embolic and cardiopulmonary risks are not entirely eliminated by avoidance of IM instrumentation alone. Fat embolism following simBTKA is well documented, with reported pulmonary or cerebral involvement ranging from 0.1% to 12% across varied surgical techniques.2,3 The underlying pathophysiology is multifactorial, involving marrow embolization, cement pressurization, systemic inflammatory response, and perioperative hemodynamic stress.2-4 Patient-related factors may further amplify risk, particularly in low- and middle-income country (LMIC) populations.4,5 Advanced age, obesity, osteoporotic bone, and the high prevalence of Vitamin D deficiency, reported in up to 70% to 90% of Indian patients with knee osteoarthritis, may predispose patients to greater marrow embolization and diminished cardiopulmonary reserve.6 These factors may partly explain the occurrence of life-threatening embolic events even in technically straightforward procedures. We congratulate the authors on their innovative approach and valuable contribution to LMIC arthroplasty literature. However, we believe that claims of complete embolic risk prevention through PST should be interpreted cautiously. Careful patient selection, meticulous intraoperative technique, vigilant cardiopulmonary monitoring, and robust postoperative surveillance remain essential safeguards in simBTKA, beyond instrumentation choices alone. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.