Sarcopenia is an Independent Risk Factor for Postoperative Blood Transfusion in Total Knee Arthroplasty: A Retrospective, Propensity Score-Matched Cohort Study
Abstract Background: Sarcopenia, an age-related loss of skeletal muscle mass and function, is correlated with adverse outcomes after some surgeries. This study examined the incidence and characteristics of sarcopenic patients undergoing primary total knee arthroplasty (TKA), and identified sarcopenia as an independent risk factor for postoperative TKA complications.Methods: A retrospective cohort study examined 452 patients who underwent TKA. The skeletal muscle index (SMI) was obtained via bioelectrical impedance analysis (BIA), along with demographics, the Charlson Comorbidity Index, and medication, laboratory and operative data for 2018–2021. Patients were categorized into non-sarcopenia (n = 417) and sarcopenia (n = 35) groups using the SMI cut-off suggested by the Asian Working Group for Sarcopenia 2019 (males, < 7.0 kg/m2; females, < 5.7 kg/m2). Three postoperative complications were analyzed: blood transfusion, delirium, and acute kidney injury (AKI). Baseline characteristics were propensity score-matched to address potential bias and confounding factors.Results: The incidence of sarcopenia in primary TKA was 7.7% (35/452). The sarcopenia group had a lower preoperative hemoglobin (12.18±1.20 vs. 13.04±1.73 g/dL, p=0.004) and total protein (6.73±0.42 vs. 7.06±0.44 mg/dL, p=0.001). Propensity scoring matching and logistic regression showed that more patients in the sarcopenia group received postoperative blood transfusions (OR = 6.60, 95% CI: 1.57–45.5, p=0.021); there was no significant difference in AKI or delirium. Univariate receiver operating characteristic curve analysis of the propensity-matched group, to determine the predictive value of SMI for postoperative transfusion, gave an AUC of 0.797 (0.633–0.96) and SMI cut-off of 5.6 kg/m2.Conclusions: Sarcopenia determined by BIA was an independent risk factor for postoperative transfusion in TKA. Multifrequency BIA can serve as a screening tool for sarcopenia. Orthopedic surgeons should be aware of this, as it could influence the decision-making process or treatment plan of patients with sarcopenia undergoing primary TKA.Level of evidence: III, retrospective cohort study
