BACKGROUND The rates of obesity among patients undergoing total knee arthroplasty (TKA) have substantially increased. In addition, obesity is a well-established risk factor for complications after TKA. The purpose of this study was to analyze trends in body mass index (BMI) and complication risk among obese patients undergoing primary TKA treated at a single institution over 3 decades. METHODS Utilizing an institutional total joint registry, 13,919 primary TKAs performed to treat osteoarthritis between 1990 and 2019 were identified. Patients were stratified by BMI according to the World Health Organization (WHO) classification into 3 groups: non-obese (BMI, <30 kg/m 2 ), WHO Class-I and II obese (BMI, 30 to 39.9 kg/m 2 ), and WHO Class-III obese (BMI, ≥40 kg/m 2 ). Trends in BMI and survivorship free from reoperation, revision, and periprosthetic joint infection (PJI) were analyzed over time while controlling for age, sex, and the Charlson Comorbidity Index. RESULTS Over the study period, there was a 90% increase in the prevalence of Class-II obesity (13% to 25%) and a 300% increase in Class-III obesity (3% to 12%). Analysis of the entire cohort demonstrated a decrease in the 2-year risk of any reoperation, any revision, and PJI (p < 0.05 for all) with time. The risk decreased significantly over time for non-obese patients for any reoperation (p = 0.029) and any revision (p = 0.004) and for Class-III obese patients for any reoperation (p = 0.038) and any revision (p = 0.012), but it remained stable for Class-I and II obese patients. The risk of PJI decreased from 1990 to 2019 for non-obese patients (p = 0.005), but there were no significant changes in PJI risk for any obesity group. CONCLUSIONS Despite increasing rates of obesity among our patients who underwent TKA, we observed decreasing risks of reoperation, revision, and PJI over time. The risks of reoperation and revision declined among non-obese patients, remained stable for Class-I and II obese patients, and declined for Class-III obese patients. The PJI risk declined for non-obese patients over the study period, but no such decline occurred for any category of obesity. Despite the decreasing risks of reoperation and revision, further work is needed to improve PJI risk in obese patients. LEVEL OF EVIDENCE Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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接受初次全膝关节置换术的肥胖患者的结果：30 年的趋势。


背景 接受全膝关节置换术 （TKA） 的患者的肥胖率大幅增加。此外，肥胖是 TKA 后并发症的公认危险因素。本研究的目的是分析在过去 3 年中在单个机构接受原发性 TKA 治疗的肥胖患者的体重指数 （BMI） 和并发症风险的趋势。方法 利用机构总联合登记处，确定了 13,919 年至 1990 年间为治疗骨关节炎而进行的 2019 例主要 TKA。根据世界卫生组织 （WHO） 分类，按 BMI 将患者分为 3 组：非肥胖 （BMI，<30 kg/m 2 ）、WHO I 级和 II 级肥胖 （BMI，30 至 39.9 kg/m 2 ）和 WHO III 级肥胖 （BMI，≥40 kg/m 2 ）。在控制年龄、性别和 Charlson 合并症指数的同时，分析了 BMI 和无再次手术、翻修和假体周围关节感染 （PJI） 的存活率随时间的变化趋势。结果在研究期间，II 级肥胖的患病率增加了 90%（13% 至 25%），III 级肥胖的患病率增加了 300%（3% 至 12%）。对整个队列的分析表明，随着时间的推移，任何再次手术、任何翻修和 PJI 的 2 年风险降低 （p < 0.05）。随着时间的推移，非肥胖患者任何再次手术 （p = 0.029） 和任何翻修 （p = 0.004） 和 III 级肥胖患者任何再次手术 （p = 0.038） 和任何翻修 （p = 0.012） 的风险显着降低，但 I 级和 II 级肥胖患者保持稳定。从 1990 年到 2019 年，非肥胖患者患 PJI 的风险有所下降 （p = 0.005），但任何肥胖组的 PJI 风险都没有显着变化。 结论 尽管接受 TKA 的患者肥胖率增加，但我们观察到随着时间的推移，再次手术、翻修和 PJI 的风险降低。非肥胖患者再次手术和翻修的风险下降，I 级和 II 级肥胖患者保持稳定，III 级肥胖患者下降。在研究期间，非肥胖患者的 PJI 风险有所下降，但任何类型的肥胖均未发生这种下降。尽管再次手术和翻修的风险降低，但仍需要进一步的工作来改善肥胖患者的 PJI 风险。证据级别 治疗级别 III .有关证据级别的完整描述，请参阅作者说明。