Total knee arthroplasty implanted with and without kinematic navigation

Between September 2000 and February 2002 we inserted 120 total knee arthroplasties. In 60 patients we used the standard technique, and in 60 patients we used the OrthoPilot navigation system. Postoperatively all patients had standing long radiographs of the lower extremity from the hip joint to the ankle. We considered the ideal value of the anatomic lateral tibiofemoral angle (LTFA) to be 174degrees. In the standard group the mean value of LTFA was 174.9degrees and in the navigation group 174.3degrees. A deviation between 0degrees and 2degrees from the ideal value was seen in 42 cases in the standard group and in 53 cases in the navigation group. In the standard group 18 cases had a deviation of more than 2.1degrees, whereas there were only seven cases in the navigation group with a deviation exceeding 2.1degrees. There were no complications related to the use of the navigation system. The system affords a possibility to place femoral and tibial components precisely with less axis deviation than with the conventional technique.