Gravius Sascha, Gebhard M, Ackermann D, Büll U, Hermanns-Sachweh B, Mumme T
Orthopädie Klinik der Rheinisch-Westfälischen Technischen Hochschule Aachen, UK Aachen, Germany.
Nuklearmedizin. 2010;49(3):115-23. doi: 10.3413/nukmed-0278. Epub 2010 Apr 20.
The AIM of this prospective study was to identify a typical pattern for fluorodeoxyglucose (18F-FDG) uptake in positron emission tomography (PET) to differentiate aseptic loosening (tibial and / or femoral component) from prosthesis infection in painful knee prosthesis.
PATIENTS, METHODS: 20 patients with painful knee prosthesis underwent PET imaging to evaluate aseptic loosening / prosthesis infection of their knee prosthesis. The interface between bone and surrounding soft tissue or bone was divided into 3 segments each for both the femur and the tibia and in addition for 4 segments reflecting the surrounding periprosthetic soft tissue. FDG uptake in each of the segments was scored (0-3) by two independent observers. The final diagnosis was based on operative findings with subsequent microbiological culture and histological examination.
After surgical revision 6 femoral components and 5 tibial components were found to be loose and prosthetic infection was present in 9 prostheses. In 8 of 9 infected prostheses loosening of the femoral und tibial component occurred. There was no statistically significant correlation between the standardised uptake within each of the segments and the diagnosis of aseptic loosening or prosthesis infection. A differentiated qualitative and quantitative FDG-PET result interpretation divided into five categories was developed. Specificity / sensitivity / positive predictive value / negative predictive value were 93% / 83% / 83% / 93% for aseptic loosening of the femoral component, 87% / 80% / 67% / 93% for aseptic loosening of the tibial component and 82% / 89% / 80% / 90% for infection.
This pilot study shows that FDG-PET is a promising diagnostic tool for patients with painful knee prostheses. There is a good correlation between PET images and the intraoperative and pathology findings. Its clinical value, however, warrants further evaluation in a larger patient population.
本前瞻性研究的目的是确定正电子发射断层扫描（PET）中氟脱氧葡萄糖（18F-FDG）摄取的典型模式，以区分疼痛性膝关节假体中的无菌性松动（胫骨和/或股骨部件）与假体感染。
患者、方法：20例疼痛性膝关节假体患者接受PET成像，以评估其膝关节假体的无菌性松动/假体感染情况。股骨和胫骨的骨与周围软组织或骨之间的界面各分为3段，此外还分为反映假体周围软组织的4段。两名独立观察者对各段的FDG摄取情况进行评分（0-3分）。最终诊断基于手术结果以及随后的微生物培养和组织学检查。
手术翻修后发现6个股骨部件和5个胫骨部件存在无菌性松动，9个假体存在假体感染。9个感染假体中有8个同时存在股骨和胫骨部件的松动。各段标准化摄取情况与无菌性松动或假体感染的诊断之间无统计学显著相关性。制定了分为五类的FDG-PET结果定性和定量的差异化解读方法。股骨部件无菌性松动的特异性/敏感性/阳性预测值/阴性预测值分别为93%/83%/83%/93%，胫骨部件无菌性松动的分别为87%/80%/67%/93%，感染的分别为82%/89%/80%/90%。
这项初步研究表明，FDG-PET对于疼痛性膝关节假体患者是一种有前景的诊断工具。PET图像与术中及病理结果之间具有良好的相关性。然而，其临床价值仍需在更大规模的患者群体中进一步评估。
