Department of Orthopedic Surgery, University of Florida, Gainesville, FL.
J Arthroplasty. 2019 Jul;34(7):1446-1451. doi: 10.1016/j.arth.2019.03.019. Epub 2019 Mar 13.
Diagnosing persistent infection following staged treatment of prosthetic joint infection (PJI) is challenging. The alpha defensin (AD) test has been shown to be an accurate diagnostic test for the primary diagnosis PJI but has limited evaluation for use following a staged treatment of PJI. The goal of this study was to evaluate the diagnostic accuracy of AD testing following staged treatment of PJI before reimplantation surgery and to determine if negative AD test predicted success following reimplantation using Delphi Criteria at time of last follow-up.
Patients who underwent AD testing prior to reimplantation after staged treatment of PJI (n = 52) were reviewed. Preoperative data (AD result, synovial fluid [SF], C-reactive protein level [mg/L], SF culture, SF white blood cell count, % of polymorphonuclear lymphocytes, serum C-reactive protein/erythrocyte sedimentation rate) and intraoperative data (purulence and tissue culture) were reviewed and used to classify patients using 2018 Musculoskeletal Infectious Disease Society criteria for infection, which was then used as a gold standard test to calculate diagnostic accuracy. Chart review was used to determine if patients who underwent reimplantation surgery would go on to treatment failure as defined by Delphi Criteria.
The sensitivity and specificity of AD test result as compared with Musculoskeletal Infectious Disease Society criteria in diagnosing PJI was calculated to be 71% and 97.78%. Positive predictive value was calculated to be 83.3%, and negative predictive value was calculated to be 95.65%. Patients who underwent reimplantation (46/52 patients) all had negative AD test results, and 9/46 or 19.5% would have treatment failure as defined by the Delphi Criteria with an average follow-up of 588 days.
AD demonstrates high specificity and negative predictive value, with low sensitivity when utilized after staged treatment of PJI. Further investigation of this and other diagnostic tests following staged treatment of PJI is needed. Additionally, validated criteria used to identify persistent infection following staged treatment of PJI are required.
诊断人工关节感染（PJI）分期治疗后的持续性感染具有挑战性。α防御素（AD）检测已被证明是原发性 PJI 的准确诊断检测方法，但在 PJI 分期治疗后使用的评估有限。本研究的目的是评估 AD 检测在 PJI 分期治疗后再植入手术前的诊断准确性，并确定在最后一次随访时使用 Delphi 标准时，AD 检测阴性是否预测再植入后的成功。
对接受 PJI 分期治疗后再植入前进行 AD 检测的患者（n=52）进行回顾性分析。回顾术前数据（AD 结果、滑膜液[SF]、C-反应蛋白水平[mg/L]、SF 培养、SF 白细胞计数、多形核白细胞百分比、血清 C-反应蛋白/红细胞沉降率）和术中数据（脓液和组织培养），并使用 2018 年肌肉骨骼感染性疾病学会（Musculoskeletal Infectious Disease Society，MIS）感染标准对患者进行分类，然后将其作为金标准检测来计算诊断准确性。通过病历回顾确定接受再植入手术的患者是否会因 Delphi 标准定义的治疗失败而继续治疗。
与 MIS 标准相比，AD 检测结果诊断 PJI 的敏感性和特异性分别为 71%和 97.78%。阳性预测值为 83.3%，阴性预测值为 95.65%。接受再植入手术的患者（52 例中有 46 例）的 AD 检测结果均为阴性，根据 Delphi 标准，9/46 例（19.5%）患者会出现治疗失败，平均随访 588 天。
AD 在 PJI 分期治疗后使用时，特异性和阴性预测值高，敏感性低。需要进一步研究 PJI 分期治疗后使用 AD 及其他诊断检测的情况。此外，还需要确定用于识别 PJI 分期治疗后持续性感染的经过验证的标准。
