Hernandez N M, Taunton M J, Perry K I, Mara K C, Hanssen A D, Abdel M P
Mayo Clinic, 200 First Street S.W., Rochester, Minnesota 55905, USA.
Bone Joint J. 2017 Nov;99-B(11):1477-1481. doi: 10.1302/0301-620X.99B11.BJJ-2017-0195.R2.
Patients with flexion instability after total knee arthroplasty (TKA) often present with a recurrent effusion, which may be a haemarthrosis. While the radiographic factors contributing to flexion instability have been elucidated, the clinical diagnosis remains challenging. Our aim, in this study, was to determine the mean white cell count and differential profile in pre-operative aspirations of synovial fluid in a consecutive series of patients undergoing revision TKA for flexion instability.
Between 2000 and 2010, 60 patients undergoing aseptic revision TKA for flexion instability were identified. The results of the pre-operative aspiration of synovial fluid were available for 53 patients (88%). These patients were 1:2 matched to 106 patients who underwent aseptic TKA for indications other than flexion instability. The mean age of the patients at revision TKA was 65 years (44 to 82) and 55% were women. The mean follow-up was 4.3 years (2 to 10.2).
In the flexion instability group, the median total cell count was 312 cells/µL (interquartile range (IQR) 104 to 624), with a mean distribution of 45% macrophages (2% to 90%), 30% lymphocytes (1% to 69%), 18% neutrophils (0% to 80%), 0.5% eosinophils (0% to 6%) and 7% other cells (0% to 42%; mainly synovial cells). There was no significant difference in the median total cell count (p = 0.14) or mean distribution of macrophages (p = 0.42), lymphocytes (p = 0.38), neutrophils (p = 0.19) and eosinophils (p = 0.89) between the flexion instability and control groups. There was a significant difference in the percentage of bloody serosanguineous aspirations which was 58% in the flexion instability group and 18% in the control group (odds ratio = 6.5; p = 0.0001).
In the group of patients who underwent revision TKA for flexion instability, most had a mean cell count and differential similar to those who underwent revision for other aseptic indications. However, bloody serosanguineous aspirations were 6.5 times more common in those with flexion instability confirming that many of the recurrent effusions seen in this condition are haemarthroses. Cite this article: 2017;99-B:1477-81.
全膝关节置换术（TKA）后出现屈曲不稳定的患者常伴有反复积液，可能为关节积血。虽然导致屈曲不稳定的影像学因素已得到阐明，但临床诊断仍具有挑战性。在本研究中，我们的目的是确定一系列因屈曲不稳定而接受TKA翻修手术的患者术前滑膜液抽吸物中的平均白细胞计数及分类情况。
2000年至2010年间，确定了60例因屈曲不稳定而接受无菌性TKA翻修手术的患者。53例患者（88%）有术前滑膜液抽吸结果。这些患者与106例因非屈曲不稳定指征而接受无菌性TKA手术的患者按1:2进行匹配。TKA翻修手术时患者的平均年龄为65岁（44至82岁），55%为女性。平均随访时间为4.3年（2至10.2年）。
在屈曲不稳定组中，总细胞计数中位数为312个/μL（四分位间距（IQR）为104至624），平均分布为45%巨噬细胞（2%至90%）、30%淋巴细胞（1%至69%）、18%中性粒细胞（0%至80%）、0.5%嗜酸性粒细胞（0%至6%）和7%其他细胞（0%至42%；主要为滑膜细胞）。屈曲不稳定组与对照组在总细胞计数中位数（p = 0.14）或巨噬细胞（p = 0.42）、淋巴细胞（p = 0.38）、中性粒细胞（p = 0.19）和嗜酸性粒细胞（p = 0.89）的平均分布上无显著差异。血性浆液性抽吸物的百分比存在显著差异，屈曲不稳定组为58%，对照组为18%（优势比 = 6.5；p = 0.0001）。
在因屈曲不稳定而接受TKA翻修手术的患者组中，大多数患者的平均细胞计数及分类与因其他无菌指征而接受翻修手术的患者相似。然而，屈曲不稳定患者中血性浆液性抽吸物的发生率高6.5倍，这证实了在此种情况下所见的许多反复积液为关节积血。引用本文：2017;99 - B:1477 - 81。
