Can rotational alignment of total knee arthroplasty be measured on MRI?

BACKGROUND AND PURPOSE: The aim of this study was to investigate the potential of MRI to determine rotational alignment after TKA in comparison to the gold standard, CT. METHODS: Rotational alignment was measured in the transverse plane on CT and MR-images in 14 patients prior to TKA revision. Differences between CT and MRI measurements were analysed. RESULTS: There was a strong correlation between CT and MRI measurements for both the tibial (r = 0.929) and femoral (r = 0.942) components with a mean difference of 0.47 ± 1.3 and 0.13 ± 3.2 degrees, respectively. INTERPRETATION: Despite artefact formation, it can be concluded that the rotational alignment of metallic TKA components can be measured by MRI as accurately as by CT.