Department of Orthopedic Surgery and Traumatology, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Department of Infectious Diseases, Hospital Clinic, University of Barcelona, Barcelona, Spain.
Arch Orthop Trauma Surg. 2022 Oct;142(10):2489-2495. doi: 10.1007/s00402-021-03868-2. Epub 2021 Mar 25.
It remains unclear whether rheumatoid arthritis might be a cause of false positive of the histology for the diagnosis of prosthetic joint infection. Our aim was to evaluate the usefulness of the histology for the diagnosis of infection during hip and knee prosthesis revision in patients with rheumatoid arthritis.
All patients with the diagnosis of rheumatoid arthritis (RA) undergoing hip or knee revision surgery (total or partial) were retrospectively reviewed. Positive histology was considered when ≥ 5 neutrophils per high-power field (400×) were found in at least five separate microscopic fields. Patients who presented ≥ 2 positive cultures for the same microorganism or the presence of fistula were considered as "true positives".
Thirty-two hip (n = 12) and knee (n = 20) revision procedures were performed. Sensitivity, specificity, positive and negative predictive value of the histology were 50%, 78.6%, 25% and 91.7%, respectively. Six out of the eight patients presenting with positive histology had negative cultures (75.0% of false positives).
Our results suggest that, in the context of RA, negative histological results have a very high negative predictive value. RA poses false positive histology results for the diagnosis of infection during hip and knee revision when conventional cultures are used for diagnosis of infection.
类风湿关节炎是否可能是假体关节感染组织学诊断假阳性的原因尚不清楚。我们的目的是评估组织学在类风湿关节炎患者髋关节和膝关节假体翻修时用于感染诊断的有用性。
回顾性分析所有诊断为类风湿关节炎（RA）并接受髋关节或膝关节翻修手术（全髋或全膝关节置换术）的患者。如果至少 5 个单独的显微镜视野中每高倍视野（400×）发现 ≥ 5 个中性粒细胞，则认为组织学呈阳性。如果患者呈现出相同微生物的 ≥ 2 次阳性培养或存在瘘管，则认为是“真正的阳性”。
共进行了 32 例髋关节（n = 12）和膝关节（n = 20）翻修手术。组织学的敏感性、特异性、阳性预测值和阴性预测值分别为 50%、78.6%、25%和 91.7%。8 例组织学阳性的患者中有 6 例培养结果为阴性（75.0%的假阳性）。
我们的研究结果表明，在 RA 背景下，阴性组织学结果具有非常高的阴性预测值。当使用常规培养物诊断感染时，RA 会导致髋关节和膝关节翻修时的感染组织学诊断出现假阳性结果。
