Comparative study of stability after total knee arthroplasties between navigation system and conventional techniques.

The aim of this study was to evaluate the stability of mediolateral laxity in extension and anteroposterior laxity in 90 degrees of flexion using stress radiographs, modified Hospital for Special Surgery scores, and range of motion of total knee arthroplasties (TKAs) performed using a navigation system (navigation-assisted group, 42 knees) after a minimum 1-year follow-up and to compare them with those of a conventional TKA (conventional group, 44 knees) using a gap technique. The mean medial laxities were 3.5 degrees in the navigation-assisted group and 4.0 degrees in the conventional group, and the mean lateral and anteroposterior laxities were 4.4 degrees and 4.2 degrees in 7.1 and 7.0 mm, respectively. These results showed no significant differences between the 2 groups. Thus, we concluded that there is no significant difference between navigation-based and conventional techniques in terms of TKA stability. In addition, no significant differences were found between the 2 groups in modified HSS scores or range of motion.