Stanford University Department of Orthopaedic Surgery, Stanford, CA, USA.
University of Hawaii John A. Burns School of Medicine, Honolulu, HI, USA.
Clin Orthop Relat Res. 2023 Oct 1;481(10):1917-1925. doi: 10.1097/CORR.0000000000002659. Epub 2023 Apr 21.
Most orthopaedic surgeons refuse to perform arthroplasty on patients with morbid obesity, citing the higher rate of postoperative complications. However, that recommendation does not account for the relationship of operative time (which is often longer in patients with obesity) to obesity-related arthroplasty outcomes, such as readmission, reoperation, and postoperative complications. If operative time is associated with these obesity-related outcomes, it should be accounted for and addressed to properly assess the risk of patients with obesity undergoing THA.
QUESTIONS/PURPOSES: We therefore asked: (1) Is the increased risk seen in overweight and obese patients, compared with patients in a normal BMI class, associated with increased operative time? (2) Is increased operative time independent of BMI class a risk factor for readmission, reoperation, and postoperative medical complications? (3) Does operative time modify the direction or strength of obesity-related adverse outcomes?
This retrospective, comparative study examined 247,108 patients who underwent THA between January 2014 and December 2020 in the National Surgical Quality Improvement Project (NSQIP). Of those, emergency cases (1% [2404]), bilateral procedures (1% [1605]), missing and/or null data (1% [3280]), extreme BMI and operative time outliers (1% [2032]), and patients with comorbidities that are not typical of an elective procedure, such as disseminated cancer, open wounds, sepsis, and ventilator dependence (1% [2726]), were excluded, leaving 95% (235,061) of elective, unilateral THA cases for analysis. The NSQIP was selected due to its inclusion of operative time, which is not found in any other national database. BMI was subdivided into underweight, normal weight, overweight, Class I obesity, Class II obesity, and Class III obesity. Of the patients with a normal weight, 69% (30,932 of 44,556) were female and 36% (16,032 of 44,556) had at least one comorbidity, with a mean operative time of 86 ± 32 minutes and a mean age of 68 ± 12 years. Patients with obesity tend to be younger, male, more likely to have preoperative comorbidities, with longer operative times. Multivariable logistic regression models examined the effects of obesity on 30-day readmission, reoperation, and medical complications, while adjusting for age, sex, race, smoking status, and number of preoperative comorbidities. After we repeated this analysis after adjusting for operative time, an interaction model was conducted to test whether operative time changes the direction or strength of the association of BMI class and adverse outcomes. Adjusted odds ratios (AOR) and 95% confidence intervals (CIs) were calculated, and the interaction effects were plotted.
A comparison of patients with Class III obesity to patients with normal weight showed that the odds of readmission went from 45% (AOR 1.45 [95% CI 1.32 to 1.59]; p < 0.001) to 27% after adjusting for operative time (AOR 1.27 [95% CI 1.01 to 1.62]; p = 0.04), the odds of reoperation went from 93% (AOR 1.93 [95% CI 1.72 to 2.17]; p < 0.001) to 81% after adjusting for operative time (AOR 1.81 [95% CI 1.61 to 2.04]; p < 0.001), and the odds of a postoperative complication went from 96% (AOR 1.96 [95% CI 1.58 to 2.43]; p < 0.001) to 84% after adjusting for operative time (AOR 1.84 [95% CI 1.48 to 2.28]; p < 0.001). Each 15-minute increase in operative time was associated with a 7% increase in the odds of a readmission (AOR 1.07 [95% CI 1.06 to 1.08]; p < 0.001), a 10% increase in the odds of a reoperation (AOR 1.10 [95% CI 1.09 to 1.12]; p < 0.001), and 10% increase in the odds of a postoperative complication (AOR 1.10 [95% CI 1.08 to 1.13]; p < 0.001). There was a positive interaction effect of operative time and BMI for readmission and reoperation, which suggests that longer operations accentuate the risk that patients with obesity have for readmission and reoperation.
Operative time is likely a proxy for surgical complexity and contributes modestly to the adverse outcomes previously attributed to obesity alone. Hence, focusing on modulating the accentuated risk associated with lengthened operative times rather than obesity is imperative to increasing the accessibility and safety of THA. Surgeons may do this with specific surgical techniques, training, and practice. Future studies looking at THA outcomes related to obesity should consider the association with operative time to focus on independent associations with obesity to facilitate more equitable access.
Level III, therapeutic study.
大多数骨科医生拒绝为病态肥胖患者进行关节置换手术，理由是术后并发症发生率较高。然而，这种建议并未考虑手术时间（肥胖患者的手术时间往往更长）与肥胖相关关节置换手术结果（如再入院、再次手术和术后并发症）之间的关系。如果手术时间与这些肥胖相关结果相关，那么就应该考虑到这一点，并加以解决，以正确评估肥胖患者接受全髋关节置换术的风险。
问题/目的：因此，我们提出了以下问题：（1）与正常 BMI 类别的患者相比，超重和肥胖患者的风险增加是否与手术时间延长有关？（2）手术时间是否独立于 BMI 类别是再入院、再次手术和术后医疗并发症的危险因素？（3）手术时间是否会改变肥胖相关不良结果的方向或强度？
这项回顾性、比较性研究检查了 2014 年 1 月至 2020 年 12 月期间在国家手术质量改进计划（NSQIP）中接受全髋关节置换术的 247,108 名患者。其中，急诊病例（1%[2404]）、双侧手术（1%[1605]）、缺失和/或无效数据（1%[3280]）、极端 BMI 和手术时间异常值（1%[2032]）以及患有非典型择期手术的合并症的患者（如弥散性癌症、开放性伤口、败血症和呼吸机依赖）（1%[2726]）被排除在外，95%（235,061）的择期单侧全髋关节置换术病例被用于分析。选择 NSQIP 是因为它包含手术时间，这在任何其他国家数据库中都找不到。BMI 被细分为体重不足、正常体重、超重、I 类肥胖、II 类肥胖和 III 类肥胖。在正常体重的患者中，69%（30,932 例/44,556 例）为女性，36%（16,032 例/44,556 例）有至少一种合并症，平均手术时间为 86 ± 32 分钟，平均年龄为 68 ± 12 岁。肥胖患者往往更年轻、男性，术前合并症更多，手术时间更长。多变量逻辑回归模型检查了肥胖对 30 天再入院、再次手术和医疗并发症的影响，同时调整了年龄、性别、种族、吸烟状况和术前合并症的数量。在调整手术时间后，我们重复了该分析，并进行了交互模型测试，以检验手术时间是否会改变 BMI 类别和不良结果之间的关联方向或强度。计算了调整后的优势比（AOR）和 95%置信区间（CI），并绘制了交互效应。
与正常体重患者相比，III 类肥胖患者的再入院率从 45%（AOR 1.45[95%CI 1.32-1.59]；p < 0.001）变为调整手术时间后的 27%（AOR 1.27[95%CI 1.01-1.62]；p = 0.04），再次手术率从 93%（AOR 1.93[95%CI 1.72-2.17]；p < 0.001）变为调整手术时间后的 81%（AOR 1.81[95%CI 1.61-2.04]；p < 0.001），术后并发症发生率从 96%（AOR 1.96[95%CI 1.58-2.43]；p < 0.001）变为调整手术时间后的 84%（AOR 1.84[95%CI 1.48-2.28]；p < 0.001）。手术时间每增加 15 分钟，再入院的几率增加 7%（AOR 1.07[95%CI 1.06-1.08]；p < 0.001），再次手术的几率增加 10%（AOR 1.10[95%CI 1.09-1.12]；p < 0.001），术后并发症的几率增加 10%（AOR 1.10[95%CI 1.08-1.13]；p < 0.001）。手术时间和 BMI 对再入院和再次手术有正交互作用，这表明手术时间延长会增加肥胖患者再入院和再次手术的风险。
手术时间可能是手术复杂性的一个指标，并对单独归因于肥胖的不良结果产生适度影响。因此，关注与手术时间相关的风险放大，而不是肥胖，对于提高全髋关节置换术的可及性和安全性至关重要。外科医生可以通过特定的手术技术、培训和实践来做到这一点。未来研究应考虑与肥胖相关的全髋关节置换术结果，同时考虑与手术时间的关联，以关注肥胖的独立关联，从而促进更公平地获得手术。
III 级，治疗性研究。
