Nguyen Natalie, Marinier Michael C, Mouser Bryan, Tappa Victoria C, Rupe Marshall, Elkins Jacob M
University of Iowa, Carver College of Medicine.
Department of Orthopedics and Rehabilitation, University of Iowa, Iowa City, IA USA.
J Electr Bioimpedance. 2025 Mar 25;16(1):35-42. doi: 10.2478/joeb-2025-0005. eCollection 2025 Jan.
Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common procedures that improve mobility but carry a risk of postoperative complications, particularly in patients with obesity. Body Mass Index (BMI) is traditionally used for risk assessment but does not account for muscle mass or fat distribution. Bioelectrical impedance analysis (BIA) provides a more detailed body composition evaluation. This study investigates the association between BIA-derived metrics and postoperative complications in TKA and THA, hypothesizing that these metrics are superior predictors compared to BMI.
A retrospective cohort study was performed on 567 adult patients who underwent primary THA or TKA from January 2020 to December 2023. The data collected included demographic characteristics, comorbidities, preoperative laboratory values, preoperative BIA measurements and postoperative complications. Multivariate logistic regression models were developed to identify independent predictors of postoperative complications. Receiver operating characteristic (ROC) curves assessed the predictive accuracy of BIA-metrics models compared to BMI model.
In a cohort of 567 patients (55.7% female, median age 66), no significant difference in BMI was found between the complication and non-complication groups. However, the complication group had a higher ECW/TBW ratio (0.396 vs. 0.393, p = 0.011), higher ECW/ICW ratio (0.657 vs. 0.647, p = 0.012), and a lower phase angle (4.65 vs. 4.80, p = 0.039). Multivariate logistic regression analysis revealed that higher standardized ECW/TBW (OR 1.65, 95% CI 1.17-2.31, p = 0.004) and ECW/ICW z-scores (OR 1.61, 95% CI 1.15-2.23, p = 0.005) were associated with increased odds of postoperative complications, while a lower phase angle was protective (OR 0.58, 95% CI 0.37-0.91, p = 0.018). ROC analysis showed moderate predictive accuracy for ECW/TBW (AUC 0.71, 95% CI 0.62-0.79), ECW/ICW (AUC 0.70, 95% CI 0.62-0.79), and phase angle (AUC 0.69, 95% CI 0.60-0.79). In contrast, BMI was not significantly associated with complications, and BMI model demonstrated inferior predictive accuracy (AUC 0.61).
ECW/TBW, ECW/ICW and phase angle are associated with postoperative complications in patients undergoing primary TKA or THA. These metrics provide better predictive accuracy than BMI enhancing preoperative risk stratification.
全膝关节置换术（TKA）和全髋关节置换术（THA）是常见的手术，可改善关节活动能力，但存在术后并发症风险，尤其是肥胖患者。传统上使用体重指数（BMI）进行风险评估，但未考虑肌肉量或脂肪分布情况。生物电阻抗分析（BIA）可提供更详细的身体成分评估。本研究调查了BIA得出的指标与TKA和THA术后并发症之间的关联，假设这些指标相比BMI是更好的预测指标。
对2020年1月至2023年12月期间接受初次THA或TKA的567例成年患者进行了一项回顾性队列研究。收集的数据包括人口统计学特征、合并症、术前实验室检查值、术前BIA测量值和术后并发症情况。建立多变量逻辑回归模型以确定术后并发症的独立预测因素。通过受试者工作特征（ROC）曲线评估BIA指标模型与BMI模型相比的预测准确性。
在567例患者队列中（女性占55.7%，中位年龄66岁），并发症组和非并发症组之间的BMI无显著差异。然而，并发症组的细胞外液/总体液（ECW/TBW）比值更高（0.396对0.393，p = 0.011），细胞外液/细胞内液（ECW/ICW）比值更高（0.657对0.647，p = 0.012），且相位角更低（4.65对4.80，p = 0.039）。多变量逻辑回归分析显示，标准化ECW/TBW升高（比值比[OR]1.65，95%置信区间[CI]1.17 - 2.31，p = 0.004）和ECW/ICW z评分升高（OR 1.61，95% CI 1.15 - 2.23，p = 0.005）与术后并发症发生几率增加相关，而较低的相位角具有保护作用（OR 0.58，95% CI 0.37 - 0.91，p = 0.018）。ROC分析显示，ECW/TBW（曲线下面积[AUC]0.71，95% CI 0.62 - 0.79）、ECW/ICW（AUC 0.70，95% CI 0.62 - 0.79）和相位角（AUC 0.69，95% CI 0.60 - 0.79）具有中等预测准确性。相比之下，BMI与并发症无显著关联，且BMI模型的预测准确性较差（AUC 0.61）。
ECW/TBW、ECW/ICW和相位角与接受初次TKA或THA患者的术后并发症相关。这些指标比BMI具有更好的预测准确性，有助于加强术前风险分层。
