Electromagnetic Navigation in TKA: A Help or Hinderance?

The value of using electromagnetic navigation in total knee arthroscopy remains a bit murky.

Between July 2007 and August 2010, Scottish and New Zealand researchers selected 200 patients scheduled for total knee arthroplasty (TKA) and randomly assigned them to undergo the procedure with either conventional instrumentation or an electromagnetic computer-assisted surgical technique; 101 patients were assigned to the navigated technique and 97 underwent TKA with the conventional approach. Ninety-two percent of knees from the navigated group and 85 percent of knees from the conventional group were implanted within 3 degrees of neutral mechanical alignment, according to the data. No differences between the two groups were noted with regard to preoperative parameters.

At the one-year follow-up, a blinded independent assessor evaluated patients, using a hand-held goniometer to determine range of motion, as well as the American Knee Society Score (AKSS) and Oxford Knee Score (OKS) to assess knee-specific measures. Additionally, SF-36 scores were used to measure patients’ general health. Implantation accuracy was determined using postoperative computed tomography scans.

The analysts observed a statistically significant difference between the groups in median tourniquet times, with 80 minutes recorded for the navigation group and 65 minutes recorded for the conventional group. Although there was a small but statistically significant difference in skin incision length of 1 centimeter, with longer incisions reported in the navigated group, no between-group differences were reported for mean drop in hemoglobin or length of hospital stay.

Between the two groups, researchers found no differences in AKSS and OKS scores, patient satisfaction, quality of life, length of stay, complication events or adverse events. There was only one deep infection in a patient within the conventional group, according to the data.