Accuracy of A Handheld Accelerometer-Based Navigation System for Femoral and Tibial Resection in Total Knee Arthroplasty

Restoration of mechanical axis in total knee arthroplasty (TKA) is correlated with improved implant survivorship. We assessed the accuracy and required surgical time using a hand-held accelerometer-based navigation system for TKA. Data collected on 53 patients included assembly, resection, and tourniquet times. Implant alignment and mechanical axis were measured on radiographs. Femoral alignment was 0.29o ± 2.2o varus. Tibial alignment was 0.09o ± 1.4o valgus. Postoperative mechanical axis was 0.2o ± 2.1o varus. Malalignment rates for the femur, tibia, and axis were 13%, 3.8%, and 17%, respectively. Average time for pinning and navigating was 3.6 minutes for the femur and 2.6 minutes for the tibia; mean tourniquet time was 62 minutes. This navigation system accurately re-established mechanical axis without increasing surgical time.