Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, OH, USA.
Clin Orthop Relat Res. 2022 Aug 1;480(8):1504-1514. doi: 10.1097/CORR.0000000000002136. Epub 2022 Feb 7.
Staphylococcus aureus is a common organism implicated in prosthetic joint infection after THA and TKA, prompting preoperative culturing and decolonization to reduce infection rates. It is unknown whether colonization is associated with other noninfectious outcomes of THA or TKA.
QUESTIONS/PURPOSES: (1) What is the association between preoperative S. aureus colonization (methicillin-sensitive S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA]) and the noninfectious outcomes (discharge destination, length of stay, Hip/Knee Disability and Osteoarthritis Outcome Score [HOOS/KOOS] pain score, HOOS/KOOS physical function score, 90-day readmission, and 1-year reoperation) of THA and TKA? (2) What factors are associated with colonization with S. aureus ?
Between July 2015 and March 2019, 8078 patients underwent primary THA in a single healthcare system, and 17% (1382) were excluded because they were not tested preoperatively for S. aureus nasal colonization, leaving 6696 patients in the THA cohort. Between June 2015 and March 2019, 9434 patients underwent primary TKA, and 12% (1123) were excluded because they were not tested for S. aureus colonization preoperatively, leaving 8311 patients in the TKA cohort. The goal of the institution's standardized care pathways is to test all THA and TKA patients preoperatively for S. aureus nasal colonization; the reason the excluded patients were not tested could not be determined. Per institutional protocols, all patients were given chlorhexidine gluconate skin wipes to use on the day before and the day of surgery, and patients with positive S. aureus cultures were instructed to use mupirocin nasal ointment twice daily for 3 to 5 days preoperatively. Adherence to these interventions was not tracked, and patients were not rescreened to test for S. aureus control. The minimum follow-up time for each outcome and the percentage of the cohort lost for each was: for discharge destination, until discharge (0 patients lost); for length of stay, until discharge (0.06% [4 of 6696] lost in the THA group and 0.01% [1 of 8311] lost in the TKA group); for HOOS/KOOS pain score, 1 year (26% [1734 of 6696] lost in the THA group and 24% [2000 of 8311] lost in the TKA group); for HOOS/KOOS physical function, 1 year (33% [2193 of 6696] lost in the THA group and 28% [2334 of 8311] lost in the TKA group); for 90-day readmission, 90 days (0.06% [4 of 6696] lost in the THA group and 0.01% [1 of 8311] lost in the TKA group); and for 1-year reoperation, 1 year (30% [1984 of 6696] lost in the THA group and 30% [2475 of 8311] lost in the TKA group). Logistic regression models were constructed to test for associations between MSSA or MRSA and nonhome discharge, length of stay greater than 1 day, improvement in the HOOS/KOOS pain subscale (≥ the minimum clinically important difference), HOOS/KOOS physical function short form (≥ minimum clinically important difference), 90-day readmission, and 1-year reoperation. We adjusted for patient-related and hospital-related factors, such as patient age and hospital site. Variable significance was assessed using the likelihood ratio test with a significance level of p < 0.05. To assess factors associated with S. aureus colonization, we constructed a logistic regression model with the same risk factors.
Among the THA cohort, after controlling for potentially confounding variables such as patient age, smoking status, and BMI, S. aureus colonization was associated with length of stay greater than 1 day (MSSA: odds ratio 1.32 [95% CI 1.08 to 1.60]; MRSA: OR 1.88 [95% CI 1.24 to 2.85]; variable p < 0.001 by likelihood ratio test) but not the other outcomes of THA. Male sex (OR 1.26 [95% CI 1.09 to 1.45]; p = 0.001) and BMI (OR 1.02 for a one-unit increase over median BMI [95% CI 1.01 to 1.03]; p = 0.003) were patient-related factors associated with S. aureus colonization, whereas factors associated with a lower odds were older age (OR 0.99 [95% CI 0.98 to 0.99]; p < 0.001) and Black race compared with White race (OR 0.64 [95% CI 0.50 to 0.82]; p < 0.001). Among the TKA cohort, S. aureus colonization was associated with 90-day readmission (MSSA: OR 1.00 [95% CI 0.99 to 1.01]; MRSA: OR 1.01 [95% CI 1.00 to 1.01]; variable p = 0.007 by likelihood ratio test). Male sex (OR 1.19 [95% CI 1.05 to 1.34]; p = 0.006) was associated with S. aureus colonization, whereas factors associated with a lower odds of colonization were older age (OR 0.99 [95% CI 0.98 to 0.99]; p < 0.001), Veterans RAND-12 mental component score (OR 0.99 [95% CI 0.99 to 1.00]; p = 0.027), Black race compared with White race (OR 0.70 [95% CI 0.57 to 0.85]; p < 0.001), and being a former smoker (OR 0.86 [95% CI 0.75 to 0.97]; p = 0.016) or current smoker (OR 0.70 [95% CI 0.55 to 0.90]; p = 0.005) compared with those who never smoked.
After controlling for the variables we explored, S. aureus colonization was associated with increased length of stay after THA and 90-day readmission after TKA, despite preoperative decolonization. Given that there is little causal biological link between colonization and these outcomes, the association is likely confounded but may be a proxy for undetermined social or biological factors, which may alert the surgeon to pay increased attention to outcomes in patients who test positive. Further study of the association of S. aureus colonization and increased length of stay after THA and readmission after TKA may be warranted to determine what the confounding variables are, which may be best accomplished using large cohorts or registry data.
Level III, therapeutic study.
金黄色葡萄球菌是人工关节置换术后假体关节感染的常见病原体，促使术前培养和去定植以降低感染率。金黄色葡萄球菌定植是否与 THA 或 TKA 的其他非传染性结局有关尚不清楚。
问题/目的：（1）术前金黄色葡萄球菌定植（甲氧西林敏感金黄色葡萄球菌[MSSA]和耐甲氧西林金黄色葡萄球菌[MRSA]）与 THA 和 TKA 的非传染性结局（出院去向、住院时间、髋关节/膝关节残疾和骨关节炎结局评分[HOOS/KOOS]疼痛评分、HOOS/KOOS 躯体功能评分、90 天再入院和 1 年再手术）之间存在何种关联？（2）哪些因素与金黄色葡萄球菌定植有关？
2015 年 7 月至 2019 年 3 月，在一个单一的医疗保健系统中，8078 例患者接受了初次 THA，其中 17%（1382 例）因术前未检测到鼻金黄色葡萄球菌定植而被排除，6696 例患者纳入 THA 队列。2015 年 6 月至 2019 年 3 月，9434 例患者接受了初次 TKA，其中 12%（1123 例）因术前未检测到金黄色葡萄球菌定植而被排除，8311 例患者纳入 TKA 队列。该机构标准化护理途径的目标是对所有 THA 和 TKA 患者术前进行金黄色葡萄球菌鼻定植检测；排除这些患者的原因无法确定。按照机构方案，所有患者均在手术前一天和手术当天使用葡萄糖酸洗必泰皮肤擦拭剂，金黄色葡萄球菌培养阳性的患者被指示使用莫匹罗星鼻软膏每天两次，连续使用 3-5 天。未跟踪这些干预措施的依从性，也未对患者进行重新筛查以检测金黄色葡萄球菌的控制情况。每个结果的最小随访时间和每个队列的失访百分比为：出院去向，直到出院（无失访）；住院时间，直到出院（THA 组 0.06%[4/6696]失访，TKA 组 0.01%[1/8311]失访）；HOOS/KOOS 疼痛评分，1 年（THA 组 26%[1734/6696]失访，TKA 组 24%[2000/8311]失访）；HOOS/KOOS 躯体功能评分，1 年（THA 组 33%[2193/6696]失访，TKA 组 28%[2334/8311]失访）；90 天再入院，90 天（THA 组 0.06%[4/6696]失访，TKA 组 0.01%[1/8311]失访）；1 年再手术，1 年（THA 组 30%[1984/6696]失访，TKA 组 30%[2475/8311]失访）。构建 logistic 回归模型，以测试 MSSA 或 MRSA 与非家庭出院、住院时间超过 1 天、HOOS/KOOS 疼痛亚量表（≥最小临床重要差异）、HOOS/KOOS 躯体功能简表（≥最小临床重要差异）、90 天再入院和 1 年再手术的改善之间的关联。我们调整了患者相关和医院相关因素，如患者年龄和医院地点。使用似然比检验评估变量的显著性，显著性水平为 p < 0.05。为了评估金黄色葡萄球菌定植的相关因素，我们构建了一个具有相同风险因素的 logistic 回归模型。
在 THA 队列中，在控制了患者年龄、吸烟状况和 BMI 等潜在混杂因素后，金黄色葡萄球菌定植与住院时间超过 1 天有关（MSSA：比值比 1.32[95%CI 1.08 至 1.60]；MRSA：OR 1.88[95%CI 1.24 至 2.85]；变量的似然比检验 p<0.001），但与 THA 的其他结局无关。男性（OR 1.26[95%CI 1.09 至 1.45]；p=0.001）和 BMI（OR 1.02 为超过中位数 BMI 的单位增加[95%CI 1.01 至 1.03]；p=0.003）是与金黄色葡萄球菌定植相关的患者相关因素，而与定植可能性较低相关的因素是年龄较大（OR 0.99[95%CI 0.98 至 0.99]；p<0.001）和黑种人（OR 0.64[95%CI 0.50 至 0.82]；p<0.001）。在 TKA 队列中，金黄色葡萄球菌定植与 90 天再入院有关（MSSA：OR 1.00[95%CI 0.99 至 1.01]；MRSA：OR 1.01[95%CI 1.00 至 1.01]；变量的似然比检验 p=0.007）。男性（OR 1.19[95%CI 1.05 至 1.34]；p=0.006）与金黄色葡萄球菌定植有关，而与定植可能性较低相关的因素是年龄较大（OR 0.99[95%CI 0.98 至 0.99]；p<0.001）、退伍军人 RAND-12 心理成分评分（OR 0.99[95%CI 0.99 至 1.00]；p=0.027）、黑种人（OR 0.70[95%CI 0.57 至 0.85]；p<0.001）和曾经吸烟者（OR 0.86[95%CI 0.75 至 0.97]；p=0.016）或当前吸烟者（OR 0.70[95%CI 0.55 至 0.90]；p=0.005）与从不吸烟者相比。
在控制我们研究的变量后，金黄色葡萄球菌定植与 THA 后住院时间延长和 TKA 后 90 天再入院有关，尽管术前进行了去定植。鉴于金黄色葡萄球菌定植与这些结局之间几乎没有因果生物学联系，这种关联可能是混杂的，但可能是未确定的社会或生物学因素的一个指标，这可能提醒外科医生更加关注定植阳性患者的结局。进一步研究金黄色葡萄球菌定植与 THA 后住院时间延长和 TKA 后再入院的关联可能是必要的，以确定混杂因素是什么，这可能最好通过大型队列或登记数据来完成。
III 级，治疗性研究。
