Abstract
Background:
Conventional, extramedullary (EM) tibial alignment guides are only 65%–88% accurate in creating a tibial resection within 2° of perpendicular to the tibial mechanical axis in total knee arthroplasty (TKA). The purpose of this study was to compare the overall, tibial component alignment, and the surgeon's ability to achieve a specific, intraoperative goal for alignment between a portable, navigation system (KneeAlign™) and conventional, EM alignment guides.
Methods:
One hundred patients were enrolled in a prospective, randomized controlled study. Fifty patients received a TKA using the KneeAlign™ to perform the tibial resection, and 50 patients an EM alignment guide. Standing AP hip-to-ankle radiographs and lateral knee-to-ankle radiographs were obtained at the first, postoperative visit.
Results:
95.7% of tibial components in the KneeAlign™ cohort were within 2° of perpendicular to the tibial mechanical axis, versus 68.1% in the conventional cohort (p < 0.001). 95.0% of the tibial components in the KneeAlign™ cohort were within 2° of a 3° posterior slope, versus 72.1% in the conventional cohort (p = 0.007).
The absolute difference between the intraoperative goal (as recorded by the surgeon) and postoperative alignment for tibial component varus/valgus was 0.9° + 0.7° in the KneeAlign™cohort, versus 1.5° + 1.1° in the conventional cohort (p < 0.001). For posterior slope, the absolute difference was 0.9° + 1.2° in the KneeAlign™ cohort, versus 1.8° + 1.7° in the conventional cohort (p = 0.01).
Conclusions:
A portable, navigation system improves tibial component alignment, and the surgeon's ability to achieve a specific, intraoperative goal, when compared to conventional, EM alignment guides in TKA.
Level of Evidence: Level I, Prospective, randomized controlled study
