Zamanzadeh Ryan S, Seilern Und Aspang Jesse, Schwartz Andrew M, Martin J Ryan, Boissonneault Adam R, Wilson Jacob M
Emory University School of Medicine, Department of Orthopaedics, Atlanta, Georgia.
University of Iowa, Department of Orthopedics and Rehabilitation, Iowa City, Iowa.
J Arthroplasty. 2023 Feb;38(2):274-280. doi: 10.1016/j.arth.2022.08.038. Epub 2022 Sep 3.
Frailty is a well-established risk factor in patients undergoing total knee arthroplasty (TKA). How age modifies the impact of frailty on outcomes in these patients, however, remains unknown. In this study, we aimed to describe and evaluate the applicability of a novel risk stratification tool-the age-adjusted modified Frailty Index (aamFI)-in patients undergoing TKA.
A national database was queried for all patients undergoing primary TKA from 2015 to 2019. There were 271,271 patients who met inclusion criteria for this study. First, outcomes were compared between chronologically young and old frail patients. In accordance with previous studies, the 75th percentile of age of all included patients (73 years) was used as a binary cutoff. Then, frailty was classified using the novel aamFI, which constitutes the 5-item mFI with the addition of 1 point for patients ≥73 years. Multivariable logistic regressions were then used to investigate the relationship between aamFI and postoperative outcomes.
Frail patients ≥73 years had a higher incidence of complications compared to frail patients <73 years. There was a strong association between aamFI and complications. An aamFI of ≥3 (reference aamFI of 0) was associated with an increased odds of 30-day mortality (odds ratio [OR] 8.6, 95% CI 5.0-14.8), any complication (OR 3.1, 95% CI 2.9-3.3), deep vein thrombosis (OR 1.5, 95% CI 1.2-1.8), and nonhome discharge (OR 6.1, 95% CI 5.8-6.4; all P < .001).
Although frailty negatively influences outcomes following TKA in patients of all ages, chronologically old, frail patients are particularly vulnerable. The aamFI accounts for this and represents a simple, but powerful tool for stratifying risk in patients undergoing primary TKA.
衰弱是全膝关节置换术（TKA）患者中一个已明确的风险因素。然而，年龄如何改变衰弱对这些患者预后的影响仍不清楚。在本研究中，我们旨在描述和评估一种新型风险分层工具——年龄调整后的改良衰弱指数（aamFI）——在接受TKA患者中的适用性。
查询一个国家数据库中2015年至2019年所有接受初次TKA的患者。有271271名患者符合本研究的纳入标准。首先，比较按年龄顺序划分的年轻和年老衰弱患者的预后。根据先前的研究，将所有纳入患者年龄的第75百分位数（73岁）用作二元分界点。然后，使用新型aamFI对衰弱进行分类，该指数由5项mFI组成，对于年龄≥73岁的患者加1分。随后使用多变量逻辑回归研究aamFI与术后预后之间的关系。
与年龄<73岁的衰弱患者相比，年龄≥73岁的衰弱患者并发症发生率更高。aamFI与并发症之间存在密切关联。aamFI≥3（参考aamFI为0）与30天死亡率增加（优势比[OR]8.6，95%可信区间5.0 - 14.8）、任何并发症（OR 3.1，95%可信区间2.9 - 3.3）、深静脉血栓形成（OR 1.5，95%可信区间1.2 - 1.8）以及非家庭出院（OR 6.1，95%可信区间5.8 - 6.4；所有P < .001）相关。
尽管衰弱对所有年龄段患者TKA后的预后有负面影响，但按年龄顺序划分的年老衰弱患者尤其脆弱。aamFI考虑到了这一点，是一种简单但强大的工具，可用于对接受初次TKA的患者进行风险分层。
