Orthopaedic Department, Kristiansund Hospital, Møre and Romsdal Hospital Trust, Kristiansund; Faculty of Medicine and Health Sciences, Department of Neuromedicine and Movement Science (INB), NTNU Norwegian University of Science and Technology.
Division of Orthopaedic Surgery, Oslo University Hospital Ullevål, Oslo; Faculty of Medicine, University of Oslo, Oslo.
Acta Orthop. 2023 Oct 31;94:550-544. doi: 10.2340/17453674.2023.24022.
Radiostereometric analysis (RSA) is the gold standard for evaluation of migration of implants. CT-RSA has been shown to have precision at the level of RSA in hip, shoulder, and knee joint replacements. We aimed to assess the impact of dose reduction on precision of CT-RSA on tibial implants, comparing it with previously published data on precision of standard dose CT-RSA on tibial implants.
We performed a total knee arthroplasty on a porcine knee cadaver, and subsequent CT-RSA with low effective doses (0.02 mSv). We compared the results with previously published CT-RSA data with standard (0.08 mSv) dose. The primary outcome variable was the difference in precision of the maximum total translation (MTT). Secondary variables included ratios of variances and standard deviations, and precision of peripheral point translations, center-of-mass translations, and rotations. A difference of more than 0.1 mm in precision was defined as clinically relevant. Our hypothesis was that precisions of low and standard CT-RSA doses were equal.
Low dose (mean 0.07, 95% confidence interval [CI] 0.06-0.08) and standard dose CT-RSA (0.08, CI 0.07-0.09) achieve similar precision, with difference in precision of MTT of 0.01, CI 0.00-0.02 mm. The F-statistic (0.99, CI 0.63-1.55) and sdtest (1.05, CI 0.43-2.58) also supported this.
We conclude that the precision of low dose CT-RSA for tibial implants on a porcine cadaver is equal to standard dose CT-RSA. However, these findings should be confirmed in clinical trials.
放射立体测量分析（RSA）是评估植入物迁移的金标准。CT-RSA 已被证明在髋关节、肩关节和膝关节置换方面具有与 RSA 相当的精度。我们旨在评估剂量降低对胫骨植入物 CT-RSA 精度的影响，并将其与之前发表的胫骨植入物标准剂量 CT-RSA 精度数据进行比较。
我们对猪膝关节尸体进行了全膝关节置换术，随后进行了低有效剂量（0.02 mSv）的 CT-RSA。我们将结果与之前发表的具有标准剂量（0.08 mSv）的 CT-RSA 数据进行了比较。主要观察变量是最大总平移（MTT）精度的差异。次要变量包括方差比和标准差，以及外周点平移、质心平移和旋转的精度。精度差异超过 0.1mm 被定义为具有临床意义。我们的假设是低剂量和标准剂量 CT-RSA 的精度相等。
低剂量（平均值 0.07，95%置信区间 [CI] 0.06-0.08）和标准剂量 CT-RSA（0.08，CI 0.07-0.09）达到相似的精度，MTT 精度差异为 0.01mm，CI 0.00-0.02mm。F 统计量（0.99，CI 0.63-1.55）和 sdtest（1.05，CI 0.43-2.58）也支持这一结果。
我们得出结论，猪尸体上胫骨植入物的低剂量 CT-RSA 精度与标准剂量 CT-RSA 相等。然而，这些发现应该在临床试验中得到证实。
