CT-based migration analysis is more precise than radiostereometric analysis for tibial implants: a phantom study on a porcine cadaver

Abstract

Background and purpose: Radiostereometric analysis (RSA) is the gold standard for migration analysis, but computed tomography analysis methods (CTRSA) have shown comparable results in other joints. We attempted to validate precision for CT compared with RSA for a tibial implant.Material and methods: RSA and CT were performed on a porcine knee with a tibial implant. Marker-based RSA, model-based RSA (MBRSA), and CT scans from 2 different manufacturers were compared. CT analysis was performed by 2 raters for reliability evaluation.Results: 21 double examinations for precision measurements for RSA and CT-based Micromotion Analysis (CTMA) were analysed. Mean (95% confidence interval) precision data for maximum total point motion (MTPM) using marker-based RSA was 0.45 (0.19–0.70) and 0.58 (0.20–0.96) using MBRSA (F-statistic 0.44 [95% CI 0.18–1.1], p = 0.07). Precision data for total translation (TT) for CTMA was 0.08 (0.03–0.12) for the GE scanner and 0.11 (0.04–0.19) for the Siemens scanner (F-statistic 0.37 [0.15–0.91], p = 0.03). When comparing the aforementioned precision for both RSA methods with both CTMA analyses, CTMA was more precise (p < 0.001). The same pattern was seen for other translations and migrations. Mean effective radiation doses were 0.005 mSv (RSA) (0.0048–0.0050) and 0.08 mSv (CT) (0.078–0.080) (p < 0.001). Intra- and interrater reliability were 0.79 (0.75–0.82) and 0.77 (0.72–0.82), respectively.Conclusion: CTMA is more precise than RSA for migration analysis of a tibial implant, has overall good intra- and interrater reliability but higher effective radiation doses in a porcine cadaver.

Dose reduction does not impact the precision of CT-based RSA in tibial implants: a diagnostic accuracy study on precision in a porcine cadaver

“…This study shows that the precision data of MTT of the lowdose CT-RSA (mean 0.07, CI 0.06-0.08) are comparable with standard-dose CT-RSA (mean 0.08, CI 0.07-0.09) (Table , Figure 3) with an F-statistic of 0.99 (CI 0.63-1.55), P = 0.9 and a corresponding sdtest of 1.05 (CI 0.43-2.58), P = 0.9. The mean difference in precision was 0.01 (CI 0.00-0.02) standard dose CT-RSA on tibial implants [10].…”

“…Maximum total translation (MTT), segmental (COM) translation and rotation, and translation of peripheral points of standard dose (0.08 mSv), low dose (0.02 mSv) CT-RSA, and mean difference with CI. The standard dose CTA-RSA data has been published previously [10] (Table ). The precision and mean difference of precision for COM translations and rotations, and peripheral point translations are also given in the Table.…”

“…This is an equivalence study that adheres to the STARD and ARRIVE guidelines [10,[14][15]. For details of the methods and materials, please see our previously published paper on this topic [10].…”

“…This is an equivalence study that adheres to the STARD and ARRIVE guidelines [10,[14][15]. For details of the methods and materials, please see our previously published paper on this topic [10]. A NexGen CR size 4 (ZimmerBiomet, Warsaw, IN, USA) was inserted in a hind knee of a porcine cadaver (Figure 1).…”

“…The introduction of CT-RSA (CT-based RSA) represents a change of paradigm in the study of early implant loosening. In CT-RSA, we use CT scans and assess the migration of implants using a special software program, e.g., CT-based Micromotion Analysis (CTMA, Sectra AB, Linköping, Sweden) [8][9][10]. Instead of using computer-aided design (CAD) models, or reverse engineered models, as in model-based RSA (MBRSA) [11], models are created in the software based on the CT scans.…”