Newman Jared M, George Jaiben, Klika Alison K, Hatem Stephen F, Barsoum Wael K, Trevor North W, Higuera Carlos A
Department of Orthopaedic Surgery, Cleveland Clinic, A41, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
Department of Radiology, Cleveland Clinic, Cleveland, OH, USA.
Clin Orthop Relat Res. 2017 Jan;475(1):204-211. doi: 10.1007/s11999-016-5093-8. Epub 2016 Sep 26.
Periprosthetic joint infection is a serious complication after THA and commonly is treated with a two-stage revision. Antibiotic-eluting cement spacers are placed for local delivery of antibiotics. Aspirations may be performed before the second-stage reimplantation for identification of persistent infection. However, limited data exist regarding the diagnostic parameters of synovial fluid aspiration with or without saline lavage from a hip with an antibiotic-loaded cement spacer.
QUESTIONS/PURPOSES: We asked: (1) For hips with antibiotic cement spacers, does saline lavage influence the diagnostic validity of aspirations? (2) What is the diagnostic accuracy of preoperative aspirations performed on hips with antibiotic cement spacers using the Musculoskeletal Infection Society (MSIS) criteria, stratified by saline and nonlavage? (3) For hips with antibiotic spacers, what are the optimal thresholds for synovial fluid white blood cell (WBC) count and polymorphonuclear neutrophil (PMN) percentage for diagnosing infections?
One hundred seventy-four hips (155 patients) with antibiotic-eluting cement spacers inserted between October 2012 and July 2015 were reviewed. Of these, 98 hips (80 patients) met the inclusion criteria and were included in the analysis (77 nonlavage, 21 saline lavage aspirations). Laboratory data from the aspiration and preoperative workup and intraoperative details were collected. Infection status of each hip procedure was determined based on a modified MSIS criteria using serologic, histologic, and intraoperative findings (sinus tract communicating with the joint at surgery or two positive intraoperative periprosthetic cultures with the same organism or two of the three following criteria: elevated erythrocyte sedimentation rate [ESR] [> 30 mm/hour] and C-reactive protein [CRP] [> 10 mg/L], a single positive intraoperative periprosthetic tissue culture, or a positive histologic analysis of periprosthetic tissue [> 5 neutrophils per high power field]). The diagnostic parameters were calculated for the MSIS criteria thresholds for synovial fluid (ie, WBC count > 3000 cells/µL and PMN percentage > 80%). Optimal thresholds were calculated for the corrected synovial WBC count and PMN percentage with a receiver operating characteristic curve. Separate analyses were performed for the hips with successful aspirations (nonlavage group) and those with saline lavage aspirations.
The WBC count and PMN percentage were higher in hips with infection than in hips without infection when nonlavage aspirations were done (WBC count, 6680 cells/µL ± 6980 cells/µL vs 2001 ± 4825; mean difference, 4679; 95% CI, 923-8436; p = 0.015; PMN percentage, 83% ± 13% vs 44% ± 30%; mean difference, 39%; 95% CI, 39%-49%; p < 0.001) and the findings between infected and noninfected aspirations were not different when saline lavage aspirations were done (WBC count, 782 cells/µL ± 696 vs 307 cells/µL ± 343; mean difference, 475; 95% CI, -253 to 1203; p = 0.161; PMN percentage, 67% ± 15% vs 58% ± 28%; mean difference, 10%; 95% CI, -11% to 30%; p = 0.331). Aspirations performed without lavage yielded good diagnostic accuracy in all parameters (WBC count, 78% [95% CI, 70%-86%]; PMN percentage. 79% [95% CI, 70%-88%]; positive culture: 84% [95% CI, 81%-90%]; at least one of the above: 79% [95% CI, 70%-88%]); but in the saline lavage group, none had WBC counts above the threshold (diagnostic accuracies for WBC count, 0%; PMN percentage, 71% [95% CI, 62%-86%]; positive culture, 76% [95% CI, 76%-86%]; at least one: 71% [95% CI, 57%-91%]). Because saline lavage did not result in differences between aspirations from infected and noninfected hips, we calculated the optimal thresholds in the nonlavage group only; the optimal threshold for synovial WBC count was 1166 cells/µL and for synovial PMN the percentage was 68%, which corresponds to WBC count diagnostic accuracy of 78% (95% CI, 69%-87%) and PMN percentage accuracy of 78% (95% CI, 69%-87%).
Because the MSIS criteria thresholds resulted in suboptimal sensitivities owing to a higher number of false negatives, we recommend considering lower WBC count and PMN percentage thresholds for hip-spacer aspirations. Furthermore, the WBC count and PMN percentage results from aspirations performed with saline lavage are not reliable for treatment decisions.
Level III, diagnostic study.
人工关节周围感染是全髋关节置换术后的一种严重并发症，通常采用两阶段翻修术治疗。抗生素骨水泥间隔物用于局部抗生素递送。在二期再植入前可进行穿刺抽吸以确定是否存在持续性感染。然而，关于使用或不使用生理盐水冲洗带有抗生素负载骨水泥间隔物的髋关节滑膜液穿刺抽吸的诊断参数的数据有限。
问题/目的：我们提出以下问题：（1）对于带有抗生素骨水泥间隔物的髋关节，生理盐水冲洗是否会影响穿刺抽吸的诊断有效性？（2）使用肌肉骨骼感染学会（MSIS）标准，对带有抗生素骨水泥间隔物的髋关节进行术前穿刺抽吸的诊断准确性如何，按是否冲洗生理盐水分层？（3）对于带有抗生素间隔物的髋关节，用于诊断感染的滑膜液白细胞（WBC）计数和多形核中性粒细胞（PMN）百分比的最佳阈值是多少？
回顾了2012年10月至2015年7月期间插入抗生素骨水泥间隔物的174例髋关节（155例患者）。其中，98例髋关节（80例患者）符合纳入标准并纳入分析（77例未冲洗，21例生理盐水冲洗穿刺抽吸）。收集了穿刺抽吸和术前检查的实验室数据以及术中详细信息。根据改良的MSIS标准，使用血清学、组织学和术中发现（手术时窦道与关节相通或术中假体周围两次培养出相同微生物阳性，或以下三项标准中的两项：红细胞沉降率[ESR]升高[>30mm/小时]和C反应蛋白[CRP]升高[>10mg/L]、术中假体周围组织培养单次阳性、或假体周围组织组织学分析阳性[每高倍视野>5个中性粒细胞]）确定每个髋关节手术的感染状态。计算了MSIS标准滑膜液阈值（即WBC计数>3000个细胞/µL和PMN百分比>80%）的诊断参数。使用受试者工作特征曲线计算校正后的滑膜WBC计数和PMN百分比的最佳阈值。对穿刺抽吸成功的髋关节（未冲洗组）和进行生理盐水冲洗穿刺抽吸的髋关节分别进行分析。
未冲洗穿刺抽吸时，感染髋关节的WBC计数和PMN百分比高于未感染髋关节（WBC计数，6680个细胞/µL±6980个细胞/µL对2001±4825；平均差异，4679；95%CI，923 - 8436；p = 0.015；PMN百分比，83%±13%对44%±30%；平均差异，39%；95%CI，39% - 49%；p < 0.001），而进行生理盐水冲洗穿刺抽吸时，感染与未感染穿刺抽吸的结果无差异（WBC计数，782个细胞/µL±696对307个细胞/µL±343；平均差异，475；95%CI，-253至1203；p = 0.161；PMN百分比，67%±15%对58%±28%；平均差异，10%；95%CI，-11%至30%；p = 0.331）。未冲洗的穿刺抽吸在所有参数中均具有良好诊断准确性（WBC计数，78%[95%CI，70% - 86%]；PMN百分比，79%[95%CI，70% - 88%]；阳性培养：84%[95%CI，81% - 90%]；上述至少一项：79%[95%CI，70% - 88%]）；但在生理盐水冲洗组中，无WBC计数高于阈值的情况（WBC计数诊断准确性，0%；PMN百分比，71%[95%CI，62% - 86%]；阳性培养，76%[95%CI，76% - 86%]；至少一项：71%[95%CI，57% - 91%]）。由于生理盐水冲洗未导致感染与未感染髋关节穿刺抽吸结果出现差异，我们仅在未冲洗组中计算了最佳阈值；滑膜WBC计数的最佳阈值为1166个细胞/µL，滑膜PMN百分比为68%，这对应WBC计数诊断准确性为78%（95%CI，69% - 87%），PMN百分比准确性为78%（95%CI，69% - 87%）。
由于MSIS标准阈值因假阴性数量较多而导致敏感性欠佳，我们建议考虑降低髋关节间隔物穿刺抽吸的WBC计数和PMN百分比阈值。此外，生理盐水冲洗穿刺抽吸获得的WBC计数和PMN百分比结果对于治疗决策不可靠。
III级，诊断性研究。
