Klett R, Steiner D, Laurich S, Bauer R, Kordelle J
Clinic of Nuclear Medicine, University Hospital Giessen and Marburg, Friedrichstrasse 25, Giessen, Germany.
Nuklearmedizin. 2008;47(4):163-6. doi: 10.3413/nukmed-0123.
In not infected knee prostheses bone scintigraphy is a possible method to diagnose mechanical loosening, and therefore, to affect treatment regimes in symptomatic patients. However, hitherto studies showed controversial results for the reliability of bone scintigraphy in diagnosing loosened knee prostheses by using asymptomatic control groups. Therefore, the AIM of our study was to optimize the interpretation procedure and to evaluate the accuracy using results from revision surgery as standard.
Retrospectively, we were able to examine the tibial component in 31 cemented prostheses. In this prostheses infection was excluded by histological or bacteriological examination during revision surgery. To quantify bone scintigraphy, we used medial and lateral tibial regions with a reference region from the contralateral femur.
To differentiate between loosened and intact prostheses we found a threshold of 5.0 for the maximum tibia to femur ratio of the both tibial regions and a threshold of 18% for the difference of the ratio of both tibial regions. Using these thresholds, values of 0.9, 1, 0.85, 1, and 0.94 were calculated for sensitivity, specificity, negative predictive value, positive predictive value, and accuracy, respectively. To get a sensitivity of 1, we found a lower threshold of 3.3 for the maximum tibia to femur ratio.
Quantitative bone scintigraphy appears to be a reliable diagnostic tool for aseptic loosening of knee prostheses with thresholds evaluated by revision surgery results being the golden standard.
在未感染的膝关节假体中，骨闪烁扫描是诊断机械性松动的一种可行方法，因此可用于影响有症状患者的治疗方案。然而，迄今为止，通过使用无症状对照组的研究显示，骨闪烁扫描在诊断松动膝关节假体的可靠性方面存在争议性结果。因此，我们研究的目的是优化解释程序，并以翻修手术结果作为标准来评估其准确性。
我们回顾性地检查了31个骨水泥固定假体的胫骨部件。在翻修手术期间，通过组织学或细菌学检查排除了这些假体的感染。为了量化骨闪烁扫描，我们使用胫骨内侧和外侧区域，并以对侧股骨作为参考区域。
为了区分松动和完整的假体，我们发现两个胫骨区域的最大胫骨与股骨比率的阈值为5.0，两个胫骨区域比率差异的阈值为18%。使用这些阈值，敏感性、特异性、阴性预测值、阳性预测值和准确性分别计算为0.9、1、0.85、1和0.94。为了获得1的敏感性，我们发现最大胫骨与股骨比率的较低阈值为3.3。
定量骨闪烁扫描似乎是诊断膝关节假体无菌性松动的可靠诊断工具，以翻修手术结果评估的阈值作为金标准。
