Luo T David, Jarvis D Landry, Yancey Hunter B, Zuskov Andrey, Tipton Shane C, Langfitt Maxwell K, Plate Johannes F
Department of Orthopaedic Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC 27157, USA.
Divison of Sports Medicine, Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC 27710, USA.
J Bone Jt Infect. 2020 Apr 22;5(3):118-124. doi: 10.7150/jbji.44815. eCollection 2020.
A synovial cell count greater than 50,000/mm is the threshold most commonly used to diagnose septic arthritis. This lab value may be nonspecific in the setting of crystalline arthropathy. The purpose of this study was to evaluate the accuracy of diagnosing septic arthritis using a synovial cell count cut-off of 50,000/mm in the setting of crystalline arthropathy. This was a retrospective review of joint aspirations performed between July 1, 2013 and June 30, 2016. Synovial fluid samples were evaluated for cell count, crystals, Gram stain, and culture. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the synovial markers were calculated. During the study period, 738 joint aspirations were sent for testing, of which 358 aspirations in 348 patients met inclusion criteria. There were 49 (13.7%) cases of culture-positive septic arthritis, and 47 patients underwent surgical irrigation and debridement. Gout and pseudogout crystals were present in 163 aspirates (45.5%). Three joints (0.8% overall rate) had concomitant crystalline arthropathy and septic arthritis, each of which had a synovial WBC ≥85,000/mm. Increasing the WBC count cutoff to 85,000/mm demonstrated a specificity of 100%, but a PPV of 12.0%. A cut-off of 85,000/mm may be more appropriate to diagnose concomitant septic arthritis and crystalline arthropathy. We recommend medical management and observation in patients with crystal-positive joint aspirations unless the synovial cell count is elevated above 85,000/mm. Prospective studies using this treatment guideline are needed to evaluate its validity and accuracy.
滑膜细胞计数大于50,000/mm³是诊断化脓性关节炎最常用的阈值。在结晶性关节病的情况下，该实验室值可能不具有特异性。本研究的目的是评估在结晶性关节病背景下，使用50,000/mm³的滑膜细胞计数临界值诊断化脓性关节炎的准确性。这是一项对2013年7月1日至2016年6月30日期间进行的关节穿刺术的回顾性研究。对滑膜液样本进行细胞计数、晶体、革兰氏染色和培养评估。计算滑膜标志物的敏感性、特异性、阳性预测值（PPV）和阴性预测值（NPV）。在研究期间，共送检738例关节穿刺术样本，其中348例患者的358例样本符合纳入标准。有49例（13.7%）培养阳性的化脓性关节炎病例，47例患者接受了手术冲洗和清创。163例样本（45.5%）中存在痛风和假性痛风晶体。三个关节（总体发生率0.8%）同时存在结晶性关节病和化脓性关节炎，每个关节的滑膜白细胞计数均≥85,000/mm³。将白细胞计数临界值提高到85,000/mm³时，特异性为100%，但阳性预测值为12.0%。85,000/mm³的临界值可能更适合诊断合并的化脓性关节炎和结晶性关节病。我们建议，对于晶体阳性的关节穿刺术患者，除非滑膜细胞计数升高至85,000/mm³以上，否则应进行药物治疗和观察。需要使用该治疗指南进行前瞻性研究，以评估其有效性和准确性。
