Radiological Evaluation of OrthAlign—A Novel Handheld Navigation System used in Total Knee Replacement

BACKGROUND: The goal of this research is to determine how well OrthAlign, a novel portable navigation system for total knee replacement, helps surgeons make accurate incisions. When comparing OrthoAlign, a portable accelerometer-based technique, to the gold standard of extramedullary jigs, the results are promising. This study aimed to evaluate the accuracy of distal femoral and proximal tibial cuts in total knee arthroplasty. MATERIALS AND METHODS: This research analyzed data from a prospective cohort study. Participants in the study all had resections of the proximal tibia and distal femur using the OrthAlign portable navigations device. Total knee arthroplasty (TKA) patients throughout the same time period who used traditional medullary alignment jigs were included as a control group. Before and after surgery, full-length standing stitch radiographs of the patient’s lower limbs were acquired so that the alignment of their knees could be assessed. RESULTS AND CONCLUSIONS: In the mechanical alignment exam done following the surgery, the OrthAlign group performed substantially better than the control group, although the difference was not statistically significant. Patients treated with OrthoAlign had considerably improved alignment of the tibial components in the coronal plane compared to those treated manually. When comparing the OrthAlign cohort to the conventional cohort, average sagittal plane alignment of tibial components was significantly different. Yet, when comparing femoral alignment after surgery, neither the mechanical alignment nor the OrthAlign groups fared better. Furthermore, there was no statistically significant difference between the two groups when it comes to the occurrence of outliers with postoperative mechanical axis alignment >3 degrees or tibial alignment in the coronal plane >2 degrees. Compared to OrthAlign, conventional alignment methods resulted in a higher percentage of postoperative tibial alignment in the sagittal plane (greater than 2 degrees). Patients whose femurs were misaligned by more than 2 degrees after surgery favored the OrthAlign method, albeit this was not statistically different from the control group. There was a significant reduction in tourniquet time for patients using OrthoAlign compared to those using mechanical alignment devices.