Department of Surgery and Cancer, Imperial College London, St Mary's Hospital, London, UK.
Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Division of Orthopaedics, Stockholm, Sweden.
Acta Orthop. 2021 Aug;92(4):419-423. doi: 10.1080/17453674.2021.1906082. Epub 2021 Apr 6.
Background and purpose - CT (computed tomography) based methods have lately been considered an alternative to radiostereometry (RSA) for assessing early implant migration. However, no study has directly compared the 2 methods in a clinical setting. We estimated the precision and effective radiation dose of a CT-based method and compared it with marker-based RSA in 10 patients with hip arthroplasty.Patients and methods - We included 10 patients who underwent total hip replacement with a cemented cup. CT and RSA double examinations were performed postoperatively, and precision and effective dose data were compared. The CT data was analyzed with CT micromotion analysis (CTMA) software both with and without the use of bone markers. The RSA images were analyzed with RSA software with the use of bone markers.Results - The precision of CTMA with bone markers was 0.10-0.16 mm in translation and 0.31°-0.37° in rotation. Without bone markers, the precision of CTMA was 0.10-0.16 mm in translation and 0.21°-0.31° in rotation. In comparison, the precision of RSA was 0.09-0.26 mm and 0.43°-1.69°. The mean CTMA and RSA effective dose was estimated at 0.2 mSv and 0.04 mSv, respectively.Interpretation - CTMA, with and without the use of bone markers, had a comparable precision to RSA. CT radiation doses were slightly higher than RSA doses but still at a considerably low effective dose.
背景与目的——最近，CT（计算机断层扫描）已被视为替代放射立体测量术（RSA）评估早期植入物迁移的方法。然而，尚无研究在临床环境中直接比较这两种方法。我们评估了一种基于 CT 的方法的精度和有效辐射剂量，并与 10 例髋关节置换患者的基于标记的 RSA 进行了比较。
患者与方法——我们纳入了 10 例接受骨水泥髋臼杯全髋关节置换的患者。术后进行 CT 和 RSA 双次检查，并比较了精度和有效剂量数据。使用 CT 微运动分析（CTMA）软件分析 CT 数据，同时使用和不使用骨标记物。使用 RSA 软件和骨标记物分析 RSA 图像。
结果——有骨标记物的 CTMA 精度在平移方向为 0.10-0.16mm，在旋转方向为 0.31°-0.37°。无骨标记物的 CTMA 精度在平移方向为 0.10-0.16mm，在旋转方向为 0.21°-0.31°。相比之下，RSA 的精度为 0.09-0.26mm 和 0.43°-1.69°。CTMA 和 RSA 的平均有效剂量估计分别为 0.2mSv 和 0.04mSv。
结论——有和无骨标记物的 CTMA 与 RSA 具有相当的精度。CT 辐射剂量略高于 RSA 剂量，但仍处于相当低的有效剂量水平。
