Precision of navigated and conventional open-wedge high tibial osteotomy in a cadaver study

Abstract

High tibial osteotomy (HTO) is an established treatment option for isolated medial osteoarthritis in young and active patients. One important factor for success of this procedure is the degree of correction of the weight-bearing line. Computer-assisted navigation systems are believed to improve the precision of axis correction through intraoperative real-time monitoring. This study investigates the precision of correction of the weight-bearing line in open-wedge HTO with and without a navigation system. Nineteen legs of well-preserved human cadaver were randomly assigned to navigated (n = 10) or conventional (n = 9) HTO. In order to achieve a sufficient amount of correction in all legs the weight-bearing line was aimed at 80 percent of the width of the tibial plateau. The mean deviation of the weight-bearing line from the desired 80 percent was 1 percent in the navigated and 8.6 percent in the conventional operated legs (p = 0.002). The weight-bearing line of all navigated but only 5 of the 9 conventional operated legs was within a +/- 5 percent tolerance level (p = 0.33). Navigated open-wedge HTO achieved better correction of the weight-bearing line than the conventional method in human cadaver legs. Future studies have to prove this advantage in a clinical setting and it's effect on patient outcome.

Figure 1

Intraoperative fluoroscopic control of the leg alignment with the use of a calibrated grid with lead-impregnated reference lines: a) determination of the hip center, b) determination of the ankle center, c) open-wedge osteotomy fixed with the HTO Position spacer plate.

Figure 2

Pre- and postoperative measurement of the leg alignment with the navigation system.

Figure 3

Distribution of the postoperative weight-bearing line (aimed at 80% of the tibial plateau width, medial edge 0%, lateral edge 100%) in navigated and conventional operated legs. Dotted lines indicate a ± 5% tolerance level.