J. George, E. M. Nageeb, G. L. Curtis, A. K. Klika, W. K. Barsoum, M. A. Mont, C. A. Higuera, Department of Orthopedic Surgery, Cleveland Clinic, Cleveland, OH, USA S. M. Navale, Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, USA.
Clin Orthop Relat Res. 2018 Oct;476(10):1951-1960. doi: 10.1007/s11999.0000000000000166.
Above-knee amputation (AKA) is a morbid procedure and is performed for a number of conditions. Although AKA is usually performed for dysvascular disease, trauma, and malignancy, AKA is also considered in patients who have failed multiple salvage attempts at treating periprosthetic joint infection (PJI) of TKA. Although aggressive measures are being taken to treat PJI, the huge volume of TKAs might result in a large number of AKAs being performed for PJI in the United States. However, the national trends in the incidence of AKAs from different etiologies and the relative contribution of different etiologies to AKA are yet to be studied.
QUESTIONS/PURPOSES: (1) What are the temporal trends in the incidence of AKAs (from all causes) in the US population from 1998 to 2013? (2) What are the temporal trends in the incidence of AKAs by etiology (dysvascular disease, trauma, malignancy, and PJI)? (3) What are the temporal trends in the relative contribution of different etiologies to AKA?
Using the Nationwide Inpatient Sample (NIS) from 1998 to 2013, AKAs were identified using International Classification of Diseases, 9 Revision (ICD-9) procedure code 84.17. The NIS database is the largest all-payer database in the United States containing information on approximately 20% of all the hospital admissions in the country. As a result of its sampling design, it allows for estimation of procedural volumes at the national level. All AKAs were grouped into one of the following five etiologies in a sequential manner using ICD-9 diagnosis codes: malignancy, PJI, trauma, dysvascular disease (peripheral vascular disease, diabetic, or a combination), and others. All of the numbers were converted to national estimates using sampling weights provided by the NIS, and the national incidence of AKAs resulting from various etiologies was calculated using the US population as the denominator. Poisson and linear regression analyses were used to analyze the annual trends.
From 1998 to 2013, the incidence of AKAs decreased by 47% from 174 to 92 AKAs per 1 million adults (incidence rate ratio [IRR]; change in the number of AKAs per 1 million adults per year; 0.96; 95% confidence interval [CI], 0.96-0.96; p < 0.001). The incidence of AKAs resulting from PJI increased by 263% (IRR, 1.07; 95% CI, 1.06-1.07; p < 0.001). An increase was also observed for AKAs from malignancy (IRR, 1.01; 95% CI, 1.00-1.02; p = 0.007), although to a smaller extent. AKAs from dysvascular causes (IRR, 0.96; 95% CI, 0.95-0.96; p < 0.001) and other etiologies (IRR, 0.97; 95% CI, 0.96-0.97; p < 0.001) decreased. There was no change in the incidence of AKAs related to trauma (IRR, 1.00; 95% CI, 0.99-1.00; p = 0.088). The proportion of AKAs resulting from PJI increased by 589% from 1998 to 2013 (coefficient = 0.18; 95% CI, 0.15-0.22; p < 0.001). The proportion of AKAs resulting from dysvascular causes decreased (coefficient = 0.18; 95% CI, 0.15-0.22; p < 0.001), whereas that resulting from malignancy (coefficient = 0.04; 95% CI, 0.03-0.05; p < 0.001) and trauma (coefficient = 0.13; 95% CI, 0.09-0.18; p < 0.001) increased.
The incidence of AKAs has decreased in the United States. AKAs related to dysvascular disease and other etiologies such as trauma and malignancy have either substantially decreased or remained fairly constant, whereas that resulting from PJI more than tripled. Given the increased resource utilization associated with limb loss, the results of this study suggest that national efforts to reduce disability should prioritize PJI. Further studies are required to evaluate the risk factors for AKA from PJI and to formulate better strategies to manage PJI.
Level III, therapeutic study.
膝上截肢（AKA）是一种病态的手术，适用于多种疾病。尽管 AKA 通常是为血管疾病、创伤和恶性肿瘤而进行的，但对于患有多种治疗人工关节感染（PJI）的翻修术失败的患者，也会考虑进行 AKA。尽管正在采取积极措施来治疗 PJI，但大量的 TKA 可能导致美国有大量的 PJI 患者需要进行 AKA。然而，不同病因的 AKA 的发病率的全国趋势以及不同病因对 AKA 的相对贡献尚未得到研究。
问题/目的：（1）1998 年至 2013 年，美国人群中所有原因导致的 AKA 的发病率有何时间趋势？（2）血管疾病、创伤、恶性肿瘤和 PJI 等不同病因导致的 AKA 的发病率有何时间趋势？（3）不同病因对 AKA 的相对贡献有何时间趋势？
使用 1998 年至 2013 年的全国住院患者样本（NIS），使用国际疾病分类，第 9 版（ICD-9）手术代码 84.17 识别 AKA。NIS 数据库是美国最大的所有支付者数据库，包含全国约 20%的住院患者信息。由于其抽样设计，它允许在全国范围内估计手术量。所有的 AKA 都按照 ICD-9 诊断代码，依次归入以下五种病因之一：恶性肿瘤、PJI、创伤、血管疾病（外周血管疾病、糖尿病或两者的组合）和其他。所有数字均使用 NIS 提供的抽样权重转换为国家估计数，并用美国人口作为分母计算出各种病因导致的 AKA 的全国发病率。使用泊松和线性回归分析来分析年度趋势。
1998 年至 2013 年，AKA 的发病率从每 100 万成年人 174 例下降到 92 例，下降了 47%（发病率比[IRR]；每年每 100 万成年人 AKA 数量的变化；0.96；95%置信区间[CI]，0.96-0.96；p < 0.001）。由 PJI 引起的 AKA 的发病率增加了 263%（IRR，1.07；95%CI，1.06-1.07；p < 0.001）。恶性肿瘤引起的 AKA 也有所增加（IRR，1.01；95%CI，1.00-1.02；p = 0.007），尽管程度较小。血管疾病引起的 AKA（IRR，0.96；95%CI，0.95-0.96；p < 0.001）和其他病因引起的 AKA（IRR，0.97；95%CI，0.96-0.97；p < 0.001）的发病率均有所下降。创伤引起的 AKA 的发病率没有变化（IRR，1.00；95%CI，0.99-1.00；p = 0.088）。由 PJI 引起的 AKA 的比例从 1998 年到 2013 年增加了 589%（系数=0.18；95%CI，0.15-0.22；p < 0.001）。血管疾病引起的 AKA 的比例下降（系数=0.18；95%CI，0.15-0.22；p < 0.001），而恶性肿瘤引起的 AKA 的比例（系数=0.04；95%CI，0.03-0.05；p < 0.001）和创伤引起的 AKA 的比例（系数=0.13；95%CI，0.09-0.18；p < 0.001）有所增加。
AKA 的发病率在美国已经下降。与血管疾病和创伤、恶性肿瘤等其他病因相关的 AKA 要么大幅减少，要么保持相当稳定，而由 PJI 引起的 AKA 则增加了两倍多。鉴于与肢体丧失相关的资源利用增加，本研究结果表明，国家减少残疾的努力应优先考虑 PJI。需要进一步研究来评估 PJI 导致的 AKA 的风险因素，并制定更好的策略来管理 PJI。
III 级，治疗性研究。
