Midterm outcomes of electromagnetic computer-assisted navigation in minimally invasive total knee arthroplasty

Background: A combination of two emerging technologies, computer-assisted navigation and minimally invasive surgery, in total knee arthroplasty has gained increasing interests from orthopedic surgeons around the world. To date, there has never been any midterm study for clinical and radiographic outcomes from using an electromagnetic computer-assisted navigation system. In this study, we aimed to systematically compare clinical and radiographic outcomes of minimally invasive surgery in total knee arthroplasty (MIS-TKA) performed with and without electromagnetic computer-assisted navigation at immediate and midterm follow-ups. Methods: A total of 151 patients (160 knees) who underwent MIS-TKA were randomized to be operated with electromagnetic computer-assisted navigation (group I: 75 patients, 80 knees) or without the navigation (group II: 76 patients, 80 knees). The clinical and radiographic outcomes of immediate, 6-week postoperative follow-up and average 6.1-year follow-up were compared. Results: On immediate, 6-week postoperative follow-up, clinical and radiographic outcomes did not reveal any difference between the two groups except for the fact that the operative time was longer in the navigation group. On 6.1-year follow-up, a total of 58 patients (63 knees) from group I and 58 patients (61 knees) from group II were reevaluated. There were no significant differences in clinical and radiographic loosening and in complications between the two groups. Conclusion: In this study, no significant differences of clinical and radiographic outcomes were found for immediate and midterm follow-ups of MIS-TKA performed with and without electromagnetic computer-assisted navigation except for the additional operating time in the navigation group.