ACCURACY OF AN ACCELEROMETER-BASED PORTABLE NAVIGATION SYSTEM IN TOTAL KNEE ARTHROPLASTY

INTRODUCTIONAn accelerometer-based portable navigation system (KneeAlign2, OrthAlign Inc., Aliso Viejo, CA) is expected to improve mechanical axis and component alignment compared to conventional instrumentation in total knee arthroplasty (TKA). However, past reports have evaluated its accuracy using only radiographic measurements. The purpose of this study was to analyze the accuracy of the KneeAlign2 system with radiography and more detailed three-dimensional (3D) CT.METHODSWe targeted 22 patients (24 knees) with severe osteoarthritis who underwent primary TKA using the KneeAlign2 system. Cemented, fixed-bearing, cruciate-retaining prostheses were implanted in all patients. We used postoperative standing-position full-length radiographic evaluation of the lower limbs to measure the hip-knee-ankle angle (HKA), frontal femoral component angle (FFC), and frontal tibial component angle (FTC). However, lower limb rotation and knee flexion could affect radiographic measurement of HKA and the component positio...