Rogers B A, Middleton F R, Shearwood-Porter N, Kinch S, Roques A, Bradley N W, Browne M
Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1XS.
J Bone Joint Surg Br. 2011 Jul;93(7):914-20. doi: 10.1302/0301-620X.93B7.25890.
Two-stage revision surgery for infected total knee replacement offers the highest rate of success for the elimination of infection. The use of articulating antibiotic-laden cement spacers during the first stage to eradicate infection also allows protection of the soft tissues against excessive scarring and stiffness. We have investigated the effect of cyclical loading of cement spacers on the elution of antibiotics. Femoral and tibial spacers containing vancomycin at a constant concentration and tobramycin of varying concentrations were studied in vitro. The specimens were immersed and loaded cyclically to 250 N, with a flexion excursion of 45°, for 35 000 cycles. The buffered solution was sampled at set intervals and the antibiotic concentration was established so that the elution could be calculated. Unloaded samples were used as a control group for statistical comparison. The elution of tobramycin increased proportionately with its concentration in cement and was significantly higher at all sampling times from five minutes to 1680 minutes in loaded components compared with the control group (p = 0.021 and p = 0.003, respectively). A similar trend was observed with elution of vancomycin, but this failed to reach statistical significance at five, 1320 and 1560 minutes (p = 0.0508, p = 0.067 and p = 0.347, respectively). However, cyclically loaded and control components showed an increased elution of vancomycin with increasing tobramycin concentration in the specimens, despite all components having the same vancomycin concentration. The concentration of tobramycin influences both tobramycin and vancomycin elution from bone cement. Cyclical loading of the cement spacers enhanced the elution of vancomycin and tobramycin.
感染性全膝关节置换的两阶段翻修手术在消除感染方面成功率最高。在第一阶段使用含抗生素的活动型骨水泥间隔物根除感染，还能保护软组织避免过度瘢痕形成和僵硬。我们研究了骨水泥间隔物的循环加载对抗生素洗脱的影响。体外研究了含恒定浓度万古霉素和不同浓度妥布霉素的股骨和胫骨间隔物。将标本浸入并循环加载至250 N，屈曲角度为45°，循环35000次。在设定的时间间隔采集缓冲溶液样本并测定抗生素浓度，以便计算洗脱量。未加载的样本用作对照组进行统计学比较。妥布霉素的洗脱量随其在骨水泥中的浓度成比例增加，与对照组相比，加载组件在5分钟至1680分钟的所有采样时间洗脱量均显著更高（分别为p = 0.021和p = 0.003）。万古霉素的洗脱也观察到类似趋势，但在5分钟、1320分钟和1560分钟时未达到统计学显著性（分别为p = 0.0508、p = 0.067和p = 0.347）。然而，尽管所有组件的万古霉素浓度相同，但随着标本中妥布霉素浓度的增加，循环加载组件和对照组件的万古霉素洗脱量均增加。妥布霉素的浓度影响骨水泥中妥布霉素和万古霉素的洗脱。骨水泥间隔物的循环加载增强了万古霉素和妥布霉素的洗脱。
