Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA.
Bone Joint J. 2020 Jun;102-B(6_Supple_A):163-169. doi: 10.1302/0301-620X.102B6.BJJ-2019-1639.R1.
The aim of this study was to determine if the local delivery of vancomycin and tobramycin in primary total knee arthroplasty (TKA) can achieve intra-articular concentrations exceeding the minimum inhibitory concentration thresholds for bacteria causing acute prosthetic joint infection (PJI).
Using a retrospective single-institution database of all primary TKAs performed between January 1 2014 and May 7 2019, we identified patients with acute PJI that were managed surgically within 90 days of the initial procedure. The organisms from positive cultures obtained at the time of revision were tested for susceptibility to gentamicin, tobramycin, and vancomycin. A prospective study was then performed to determine the intra-articular antibiotic concentration on postoperative day one after primary TKA using one of five local antibiotic delivery strategies with tobramycin and/or vancomycin mixed into the polymethylmethacrylate (PMMA) or vancomycin powder.
A total of 19 patients with acute PJI after TKA were identified and 29 unique bacterial isolates were recovered. The mean time to revision was 37 days (6 to 84). Nine isolates (31%) were resistant to gentamicin, ten (34%) were resistant to tobramycin, and seven (24%) were resistant to vancomycin. Excluding one , which was resistant to all three antibiotics, all isolates resistant to tobramycin or gentamicin were susceptible to vancomycin and vice versa. Overall, 2.4 g of tobramycin hand-mixed into 80 g of PMMA and 1 g of intra-articular vancomycin powder consistently achieved concentrations above the minimum inhibitory concentrations of susceptible organisms.
One-third of bacteria causing acute PJI after primary TKA were resistant to the aminoglycosides commonly mixed into PMMA, and one-quarter were resistant to vancomycin. With one exception, all bacteria resistant to tobramycin were susceptible to vancomycin and vice versa. Based on these results, the optimal cover for organisms causing most cases of acute PJI after TKA can be achieved with a combination of tobramycin mixed in antibiotic cement, and vancomycin powder. Cite this article: 2020;102-B(6 Supple A):163-169.
本研究旨在确定在初次全膝关节置换术（TKA）中局部给予万古霉素和妥布霉素是否可以达到关节内浓度，超过引起急性人工关节感染（PJI）的细菌的最低抑菌浓度阈值。
我们使用 2014 年 1 月 1 日至 2019 年 5 月 7 日期间在一家机构进行的所有初次 TKA 的回顾性单机构数据库，确定了在初次手术后 90 天内接受手术治疗的急性 PJI 患者。在翻修时获得的阳性培养物中的细菌对庆大霉素、妥布霉素和万古霉素的敏感性进行了测试。然后进行了一项前瞻性研究，以确定在初次 TKA 后第 1 天使用五种局部抗生素递送策略之一（将妥布霉素和/或万古霉素混合到聚甲基丙烯酸甲酯（PMMA）或万古霉素粉末中）后的关节内抗生素浓度。
共确定了 19 例初次 TKA 后发生的急性 PJI 患者，共分离出 29 种独特的细菌分离株。平均翻修时间为 37 天（6 至 84 天）。9 种分离株（31%）对庆大霉素耐药，10 种（34%）对妥布霉素耐药，7 种（24%）对万古霉素耐药。排除一种对所有三种抗生素均耐药的分离株，所有对妥布霉素或庆大霉素耐药的分离株均对万古霉素敏感，反之亦然。总的来说，将 2.4 克妥布霉素手动混合到 80 克 PMMA 中和 1 克关节内万古霉素粉末中始终可以达到敏感生物体的最低抑菌浓度以上的浓度。
初次 TKA 后引起急性 PJI 的三分之一细菌对通常混合到 PMMA 中的氨基糖苷类药物耐药，四分之一对万古霉素耐药。除一个例外，所有对妥布霉素耐药的细菌对万古霉素敏感，反之亦然。基于这些结果，对初次 TKA 后大多数急性 PJI 引起的细菌，可通过妥布霉素混合抗生素水泥与万古霉素粉末联合应用来实现最佳覆盖。
2020；102-B（6 增刊 A）：163-169.
