Department of Orthopaedic Surgery, IDIBELL, Hospital Universitari de Bellvitge, Feixa Llarga s/n. 08907, L'Hospitalet de Llobregat, Barcelona, Spain.
J Infect. 2011 Jul;63(1):23-31. doi: 10.1016/j.jinf.2011.04.014. Epub 2011 May 19.
Antibiotic-loaded spacers may improve antimicrobial efficacy in two-stage revision of prosthetic joint infections, but they may also interfere in the course of infection. This prospective study of prosthetic joint infections managed with two-stage revision and antibiotic-loaded spacers (2004-09) analyzes case outcomes and proposes a second-stage culture interpretation scheme.
Second-stage infection was diagnosed upon second-stage cultures (synovial membranes, joint fluid, spacers), as either superinfection (≥2 samples, new organism) or persistence (≥1 samples, previously isolated organism). Isolated positive antibiotic-loaded spacers cultures were considered as colonizations.
Of 42 patients, two had two prosthetic infections (n = 44): 25 knees, 19 hips. Spacers contained gentamicin (33), vancomycin (10) and aztreonam (1). Three patients (7%) with wound healing impairment required debridement and spacer exchange. The remainder underwent second-stage surgery as planned: 34 (77%) new arthroplasties, five arthrodeses, one resection arthroplasty and one permanent spacer. Of 18 cases (44%) with ≥1 positive sample, only four (10%) were second-stage infections. Fourteen antibiotic-loaded spacers cultures (34%) were positive. Four new prostheses (9%) supervened further infections: one by the organism isolated in the spacer, three by new bacteria.
The findings of second-stage cultures show that the surgical site is frequently non-sterile at reimplantation. Isolated positive antibiotic-loaded spacer cultures usually have no clinical consequences, but together with tissue cultures they help to diagnose second-stage infections when clinical signs are absent.
抗生素载药 spacer 可提高二期翻修治疗假体关节感染的抗菌疗效，但也可能影响感染进程。本前瞻性研究分析了采用二期翻修和抗生素载药 spacer 治疗假体关节感染（2004-09 年）的病例结局，并提出了二期培养物解读方案。
二期感染根据二期培养物（滑膜、关节液、 spacer）诊断，分为再感染（≥2 个样本，新病原体）或持续感染（≥1 个样本，先前分离的病原体）。分离出的阳性抗生素载药 spacer 培养物被认为是定植。
42 例患者中有 2 例发生 2 次假体感染（n=44）：25 例膝关节，19 例髋关节。 spacer 中含庆大霉素（33 例）、万古霉素（10 例）和氨曲南（1 例）。3 例（7%）存在伤口愈合不良的患者需清创和 spacer 更换。其余患者按计划行二期手术：34 例（77%）行新关节置换术，5 例行关节融合术，1 例行切除关节成形术，1 例行永久 spacer。18 例（44%）≥1 个样本阳性的患者中，仅有 4 例（10%）为二期感染。14 例抗生素载药 spacer 培养物（34%）阳性。4 例新假体（9%）发生进一步感染：1 例由 spacer 中分离的病原体引起，3 例由新细菌引起。
二期培养物的结果显示，再植入时手术部位常为非无菌状态。孤立的阳性抗生素载药 spacer 培养物通常无临床后果，但结合组织培养物，当临床症状不明显时，有助于诊断二期感染。
