Computed tomography evaluation of total knee arthroplasty implants position after two different surgical methods of implantation

PurposeThe objectives of this study were to determine the reliability of a novel method of measuring the rotational alignment of an anatomical tibial tray, the difference in the rotational alignment of the femoral and tibial component according to pure measured resection or blended technique with tensor, and, finally, the difference in terms of clinical results according to the two different methods.Patients and methodsWe performed a total of 60 consecutive TKAs: 30 according to pure measured resection and 30 according to blended technique with tensor (FuZion (R)). Clinical scores and CT scan were done at sixmonths to measure patient's outcome and prosthetic components rotation.ResultsThe method of measurement of tibial tray had high agreement between different radiological observers. Mean external rotation alignment of the femur was 2.7 degrees in standard group and 0.5 degrees in the FuZion (R) group. For all clinical indices, we observed a large and significant improvement at follow-up, better in blended technique group, but without a clear superiority, and no statistically significant difference was evident between the two groups. At follow-up, HSS was to 89.7 in the FuZion (R) group and 89.0 in the standard group, KSS (clinical) was 92.6 in and 91.3 respectively, and KSS (Functional) was 91.0 in the FuZion (R) group and 87.6 in the standard group.ConclusionsOur CT measurement method is reliable and reproducible. All patients operated with this personalized knee system design obtained excellent results; the customization of femoral rotation with a blended technique is, probably, the key to optimize the outcomes and achieve the state of forgotten knee.